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CHAPTER 1: INTRODUCTION
When talking about the petrochemical industry, most of the people will first imagine about
the production of the car fuel, plastic products or even the cooking gas. However, the industry isindeed more than that. Various types of products can be derived from the raw fossil fuels,
depending on the projects that the producers are working on.
RAPID with its full name Refinery and Petrochemical Integrated Development is the
focus on this Design Feasibility Study report. In this report, RAPID major production components
are the proposed refinery with refining capacity of 150,000 barrels-per-day sour crude oil and
acrylonitrile production plant with an annual production of approximately 120,000 tons per
annum.
1.1 SOUR CRUDE OIL
Basrah sour crude oil from Middle East (Iraq) is being chosen as the main raw material for
the process production. The term sour is used due to its high content of impurity sulphur, and
thus it needs to be refined into sweet crude oil before it can proceeds to the next process. Based on
statistic, Iraqs oil exports rise to an average of 2.565 million barrels per day in August, 2012
from 2.516 million barrels per day in July, 2012. This is recorded to be the highest level in three
decades (according to Reuters).[1] Figure 1.1 shows the present and the forecast crude oil
production of some oil producer country such as Iraq, Brazil, Canada, Nigeria and Russia.
Figure 1.1: The current and expected statistics for the capacity of crude oil producers. [2]
As can be seen, the expected producing rate of crude oil for Iraq is positive in the next 10
years. This is due to theIraqs government proactive plans, such as securing license for several
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existing oil field. This intends on expanding the production capacity of the crude oil on its fullest
potential.[2] Therefore, sour crude oil is imported from Basrah, Iraq (Middle East) to be the
feedstock of the refinery plant in this RAPID design project.
1.2 ACRYLONITRILE
Acrylonitrile is chosen as the final product for this RAPID design project. Basically, the
primary uses for acrylonitrile are the chemical intermediate in acrylic fibres, ABS (acrylonitrile-
butadiene-styrene), SAN (styrene-acrylonitrile), NBR (nitrile-butadiene-rubber), acrylamide
(manufacture of various polymers) and adipronitrile (used to make Nylon 6,6). This is due to its
extensive commercial and industrial applications as tough, durable synthetic rubbers and
engineering plastics.[3, 4] The percentage of the applications of acrylonitrile is presented in a pie
chart as shown in figure 1.2.
Figure 1.2: The percentage uses of acrylonitrile.[4]
In addition, acrylonitrile is also used in manufacturing of polyacrylonitrile (PAN) for
acrylic fibre, this is used in apparel, household furnishings, industrial markets and applications.
Besides, acrylonitrile is the chemical intermediates to synthesis various antioxidants,
pharmaceuticals, dyes and surface-active.
In the year of 2007, global demand on acrylonitrile reaches the highest peak but it was
decreased by about 13% in 2008, which was resulted by the global economic downturn. However,
Fibres52%
ABS and SANS15%
Acrylamide, Adipronitrile
15%
Other uses18%
Applications of Acrylonitrile
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in the beginning of the year 2009, the global demand recovered at an average annual rate of 5%.
The bulk growth of acrylonitrile demand is taking place in Asia, and it is driven by the constant
development of the electrical appliances and also the automotive industries. The bar chart below
depicts the global acrylonitrile consumption for the year 2011 for various countries.[5]
Figure 1.3: The percentage uses of Acrylonitrile consumption according to region in 2011. [5]
As can be seen, the highest demand comes from China and other parts of Asia. It is
positive news for the plant project, as the targeted market for the plant product is Malaysia, China,
India and also Indonesia.
1.3 REFERENCES
[1] Lee, J., Iraqi Oil Exports Hit New Highs. (2012). Retrieved 8 October 2012, fromhttp://www.iraq-businessnews.com/tag/somo/
[2] Purvin, G.H.,Crude Demand to increase, Feed Quality Changes in store. (2010). Retrieved 8October 2012, from http://www.ogj.com/articles/print/volume-108/issue-46/processing/crude-demand-to-increase-feed-quality.html
[3] Tech., I., Acryonitrile properties. (2012). Retrieved 8 October 2012, fromhttp://www.ineostechnologies.com/83-process.htm
[4] Europe, A.o.P.P.i., Acrylonitrile usage and properties. (2012). Retrieved 8 October 2012,from http://www.petrochemistry.net/acrylonitrile.html
[5] Chemical, IHS., Acrylonitrile . (2012). Retrieved 8 October 2012, fromhttp://www.ihs.com/products/chemical/planning/ceh/acrylonitrile.aspx
0
5
10
1520
25
30
35
40
China Other Asia WesternEurope
North America Japan Others
Percentage of World Acrylonitrile Consumptionin 2011
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CHAPTER 2: FEEDSTOCK
2.1 SELECTION OF CRUDE OIL PRODUCER
By referring to the world oil reserved graph as shown in figure 2.1, the largest oil- producing exporter is in the Middle East as every country in the middle east are an oil-rich and the
term Middle East and oil -rich ar e often taken together as synonym. Iraq, one of the countries
in the Middle East is selected to be the best option for the oil supplier. Table 2.1 is the break, by
table ranking Middle Easts oil -rich countries according to known oil reserves.[1]
Figure 2.1: World Oil Reserves by Region in 2007 [1] .
Table 2.1: The Middle East's Oil Producer. [1]
Rank Country Reserves
(billions of barrels) 1 Saudi Arabia 262.3
2 Iran 136.3
3 Iraq 115
4 Kuwait 101
5 United Arab Emirates 97.8
6 Libya 41.5
Africa9%
Asia & Oceana3%
NorthAmerica
16%
Central & SouthAmerica
8%Europe
1%Eurasia7%
Middle East56%
World Oil Reserves by Region
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2.1.1 Supporting Facts and Reasoning
The source of crude oil is obtained directly from Basra Oil, Iraq which is located in the
Middle East. Basra (34.4 API and 2.10% sulphur)[2] is high-grade oils, the light and average
sulphur content most similar to the Arab Light grade from Saudi Arabia. Even though Iraq is in3rd rank, it has highest reserve life (proven reserves/annual production) of all oil producers. It has
vast and relatively undeveloped oil resources. Iraq also has a large south-western desert territory
that has not yet been fully explored and is estimated to contain up to 100 billion barrels of
additional oil reserves[3]. Saudi Arabia which is in the 1st rank is not chosen as the oil supplier due
to some speculation that Saudi consumption of oil would outstrip production and they could
importing oil instead of exporting it[4]. Hence, to avoid such problem in the future for oil supplier,
Basra Oil, Iraq is chosen over Saudi Arabia.
Table 2.2: The distillation yields (% wt) of Basra Oil, Iraq. [5]
Distilation Yields (% wt) Basra Oil
C1 to C4 1.6
Naphtha (C5 to 149 C) 14.4
Kerosene (149 C to 232 C) 12.5
Gas oil (232 C to 342 C) 17.1
Atmospheric Residue (342 C +) 54.5
According to BP Statistical Review of World Energy, June 2011, Iraq is the world 3rd
largest oil reserve capacity country, with 115 billion barrels of oil reserve. On December 11 2009,
Iraq Oil Minister Hussain al-Shahristani confirm the trade agreement between Iraq and
Malaysias state-run oil company, Petronas together with European oil giant, Shell, where
both companies has won the rights to develop Iraqs giant Majnoon oil field, an almost 13
billion barrel behemoth. The trade agreement last for 20 years and approved by Iraqs
cabinet. Hence, the feedstock availability is stable and reliable for the future coming years.
2.2 MARKET SURVEY ON FEEDSTOCK FOR ACRYLONITRILE
This section will determine which type of feedstock is more feasible option for this new
acrylonitrile plant. The major hydrocarbon sources used in producing propylene are Methane,
Ethane, Butanes which is obtained primarily from natural gas processing plants and Naphtha and
Gas Oil which are obtained from petroleum refineries.
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Figure 2.2: Feedstock for Olefins Production in Year 1992.[1]
Figure 2.3: Feedstock for Olefins Production in Year 2012 [2]
Relatively small amount of propylene is produced when natural gas is used as the
feedstock while a comparatively significant amount of propylene is produced when crude oil is
used[6]
. Naphtha which is produced from crude oil through refinery process shows highest percentage among the five feedstocks as shown in Figure 2.2 and Figure 2.3. It is decided to
choose Basra Oil from Iraq as the crude oil supplier and the facts and reasoning as stated before.
2.2.1 Naphtha
Naphtha is used as the feedstock for fluid catalytic cracking process to produce the co-
products which are propylene, ethylene and butadiene. In general, there are two types of naphtha
which are light naphtha and heavy naphtha. Light naphtha consists of molecules with 5 to 6
carbon atoms whereas heavy naphtha consists of molecules with 6 to 12 carbons.
Naphtha50%
Others2%
Ethane26%
Propane11%
Butane4%
Gas Oil7%
1992
Naphtha52%
Others1%
Ethane23%
Propane12%
Butane5%
Gas Oil7%
2012
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2.2.2 Comparison of Light and Heavy Naphtha
Table 2.3 below summarized the comparison between Light Naphtha and Heavy Naphtha.
Table 2.3: Comparison between Light and Heavy Naphtha as feedstock.
From the comparison, when the major products desired are olefins, light naphtha will be
the favoured feedstock whereas heavy naphtha are used as feed in plants that desired to produce
aromatic products. Heavy naphtha requires that the cracking furnaces be operated at relative
higher temperatures compared to light naphtha feed in order to obtain the same yield percentage.
Light Naphtha was chosen over heavy naphtha as it yields more olefins and required less stringent
furnace operating conditions and has a lower rate of coking.
2.3 CONCLUSION
In a nutshell, Light Naphtha is the best option rather than heavy naphtha as our feedstock
due to reason as below:
a) Higher yield of olefins.
b) Lower coking rate.
c) Less stringent furnace operating conditions.
The feedstock Basra Oil will be shipped from Iraq, Middle East to the proposed plant location,
Pengerang Port, Johor.
Factors Light Naphtha Heavy NaphthaParaffin content High Less and contain more
aromatic compound.
Approximate Boiling
Range, oC
25-90 85-190
Major product Olefins products Aromatic products
Cracking temperature Require less than heavy
naphtha.
Require high operating
temperature of crackingfurnace.
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2.4 REFERENCES
[1] Wang, S. and E. Ariyanto,Competitive adsorption of malachite green and Pb ions on natural
zeolite. Journal of Colloid and Interface Science, 2007.314 (1): p. 25-31.[2] Brown, J. Quality Or Quantity . (2011). Retrieved 5 December, 2012, from
http://www.oilslick.com/commentary/?id=2332&type=1. [3] Avery, C., Iraqi Oil Industry . (2010).[4] Aluwaisheg, A.A.,Will Saudi Arabia become an oil importer by 2030 , in Arab News . (2012).[5] BP, L.I.O. Basra Light . (2012). Retrieved 5 December, 2012, from
http://www.bp.com/extendedsectiongenericarticle.do?categoryId=9035920&contentId=7066556.
[6] Gazette, S. Demand driven by packaging, automotive sectors Retrieved 8 December 2012,
fromhttp://www.gulfinthemedia.com/index.php?m=economics&id=536655&lim=180&lang=en&t blpost=2010_10&PHPSESSID=8.
http://www.oilslick.com/commentary/?id=2332&type=1http://www.bp.com/extendedsectiongenericarticle.do?categoryId=9035920&contentId=7066556http://www.bp.com/extendedsectiongenericarticle.do?categoryId=9035920&contentId=7066556http://www.gulfinthemedia.com/index.php?m=economics&id=536655&lim=180&lang=en&tblpost=2010_10&PHPSESSID=8http://www.gulfinthemedia.com/index.php?m=economics&id=536655&lim=180&lang=en&tblpost=2010_10&PHPSESSID=8http://www.gulfinthemedia.com/index.php?m=economics&id=536655&lim=180&lang=en&tblpost=2010_10&PHPSESSID=8http://www.gulfinthemedia.com/index.php?m=economics&id=536655&lim=180&lang=en&tblpost=2010_10&PHPSESSID=8http://www.bp.com/extendedsectiongenericarticle.do?categoryId=9035920&contentId=7066556http://www.bp.com/extendedsectiongenericarticle.do?categoryId=9035920&contentId=7066556http://www.oilslick.com/commentary/?id=2332&type=1 -
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CHAPTER 3: PRODUCTS AND CO-PRODUCT 3.1 MARKET SURVEY
This market survey will only focus on the Asia region, which including 4 major markets
such as Malaysia, China, India and last but not least Indonesia. Figure 3.1 shows the potential
demand of Asia is huge especially from year 2013 to year 2018.
Figure 3.1a: The Production and Demand of Acrylonitrile in Various Regions in year 2013[9] .
Figure 3.1b: The Production and Demand of Acrylonitrile in Various Regions in year 2018[9] .
From Figure 3.2a and Figure 3.2b, there is huge potential in Asias acrylonitrile demand
market, where China and India are determined to be stable net importers of acrylonitrile. The
capacity demanded is always higher than the production rate. This shows that China and India,
which has 35 % world population (2.3 billion out of 7 billion) are indeed a huge goldmine for
acrylonitrile market.
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Figure 3.1 c: The Acrylonitrile Capacity Utilisation in China [9] .
Figure 3.1 d: The Acrylonitrile Capacity Utilisation in India [9] .
Table 3.1 shows the planned addition of acrylonitrile capacity in the Asia for the future five years.
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Table 3.1: Planned Additions of Acrylonitrile Capacity [9] .
From Table 3.1, it can be deduced the regional total capacity of acrylonitrile is only 2603
000 tons, which is far more less than the minimum capacity needed, 3000 000 tons shown isFigure 3.1a. Moreover, BP CHEMICALS estimates that global acrylonitrile demand will grow by
3% per year, helped largely by China. This would require an extra 150 000 tonne of supply
annually [2] .Furthermore, according to Asahi Kasei Chemicals, acrylonitrile demand in Asia
region is forecast to grow at 5% constantly[1] .Hence, it can be concluded that selling acrylonitrile
to Asia Region was economically feasible in this modern times. Such a conclusion was supported
by Mr Yee Nai Tuck, Senior Deputy Director of Malaysian Investment Development Authority
(MIDA) on 27th October 2012 during his seminar talk at Chemical Engineering Department of
University Malaya. (It is left to the reader to decide the reliability of his opinion)
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3.2 CO-PRODUCT HYDROGEN CYANIDE
Direct production accounts for about 70% of the total capacity and the balance is derivedas co-product material from acrylonitrile production. The following pie chart shows world
consumption of hydrogen cyanide:
Figure 3.2 World Consumption of Hydrogen Cyanide. [2]
Between 2005 and 2009, total consumption of hydrogen cyanide in the United States,
Western Europe and Japan increased by about 2% per year. Global consumption is expected to
increase at an average rate of around 1 2% per year from 2009 through 2019, assisted by
increased demand for nutritional additives and higher demand market from Asia countries,especially China and India, although the increased consumption in Western Europe was offset by
reductions in Japan (due to nuclear meltdown incidents in Fukushima, it affects the world
petrochemical market) and stagnation in the United States resulting from reduced demand for
adiponitrile[2].
The major end uses for hydrogen cyanide include adiponitrile and sodium cyanide. Due to
its toxicity, hydrogen cyanide is usually consumed at its site of production. In March
2012, PETRONAS and BASFhave entered into a Heads of Agreement (HOA) for the RAPID.
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Under the terms of theHOA , the partners have agreed to form a joint venture (BASF 60%;
PETRONAS 40%) to develop, construct and operate production facilities for several
petrochemical products, and one of product goes to adiponitrile. Hence, the by-product hydrogen
cyanide will be sold to BASF plant for further processing into adipontrile.3.3 CO-PRODUCT ACETONITRILE
Acetonitrile is a co-product in the manufacture of acrylonitrile by ammoxidation of
propylene at a rate of about 2 3% of acrylonitrile production. The following pie chart shows
world consumption of acetonitrile:
Figure 3.3 World Consumption of Acetonitrile. [2]
Consumption of acetonitrile in the pharmaceutical and analytical industries has
experienced solid growth. The pharmaceutical industry is the largest end use for acetonitrile. It is
estimated that approximately half of China's consumption of acetonitrile is for the production of
vitamin B1, half of which is then exported worldwide. The use of acetonitrile in pharmaceutical products for diseases has grown rapidly in recent years, boosted by improved living standards in
industrialized countries. Consumption of acetonitrile for pharmaceuticals will continue to grow
during the next five years, which is from year 2011 to 2016.
World consumption is forecast to continue to grow at a rate of about 5% per year over the
next five years. The highest growth rate (about 8 9% per year) is expected for China and India,
because of the increasing production of engineered drugs, generic pharmaceuticals and pesticidesin these countries. In Europe (including Switzerland) and in the United States, the annual growth
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rate for 2010 2015 is estimated at 2%. Hence, the separation of acetonitrile from the main final
product will be an economic feasible and profitable plan, besides that focusing only on the main
product, acrylonitrile.
3.4 DESCRIPTION OF SOURCE AND DEMAND COUNTRIES .
Over the world there are vast producers of acrylonitrile specifically from Europe, Asia,
America and Middle East. The proposed plant of this acrylonitrile plant will focus more on the
demand countries like China, Indian, Malaysia and Indonesia and some of theAsias producers
are Japan, South Korea, Taiwan and Thailand.
3.4.1 China [3]
China is the largest acrylonitrile producer in Asia region with higher number of producers
such Anqing Petrochemical, Daqing Refining & Chemical ,Fushun Petrochemical Co, Jilin
Petrochemicals Ltd (JLPL), Lanzhou Petrochemical Corp, Maoming Petrochemical Corp
(MPCC) (Shenzhen SE), Ningbo Shunze Rubber Co, Qilu Petrochemical Co Ltd and Sinopec
Corp. Acrylonitrile prices have been climbing up and this force to China increase the production
over the years and focusing more on the concerned issues regarding the development of
acrylonitrile and its by product. They also promote and encourage producers, traders and
downstream customers to exchange info and ideas regarding the strong development of
acrylonitrile. In the 9th China International Acrylonitrile Forum on8th March 2012, China has
revealed their new import trade of raw material from South Korea, Taiwan and Japan will hike up
in order to fulfil with their demand of acrylonitrile in the country and creating over opportunity to
expand globally. China is subjected to remain one of the market importers with 20% market
dependency for the coming 5 years.
3.4.2 India [4] India has starting steps for acrylonitrile but from Acrylonitrile Industry Outlook in India to
2016, they had capacity forecast to be increase and their market trends will be the new
development for acrylonitrile. Reliance Industries Ltd is the major acrylonitrile producer in India
and their market size was comparably small, with 50,000 tons (refer Table 3.1) acrylonitrile per
annum. However, India require an import demand of 1650,000 tons (refer figure 3.1b)
acrylonitrile per annum in 2013 even with its current expansion plan, moreover with statistic
support that their import demand will keep hiking up with 4% per annum. India has begun with
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their new benchmark where they proposed to have new market entry and market expansion within
2016.
3.4.3 Japan[5]
Japans Acrylonitrile industry has a consistent plant capacity growth and major of its
product were exported. Their trading amount of acrylonitrile to other part of Asia country leads
the growth of acrylonitrile in Japan. Current acrylonitrile producer in Japan are Asahi Kasei Corp,
Dia-Nitrix Co Ltd, Showa Denko KK (Shoden) and Sumitomo Chemical Co Ltd. They had a
dynamic strength from year 2000 and predicted that the strength in acrylonitrile production will
goes on till 2016 in Asia region. However, due to nuclear meltdown incidents in Fukushima on
year 2011, it affects the world petrochemical market and reductions in production of acrylonitrile
in Japan. Japan has in fact intends to reduce its acrylonitrile production by 5-7 % over the next 5
years due to saturation of demand in Japan[8] .This will no doubt that shortage of acrylonitrile will
happen in Asia due to strong demand dominated by China and India. With the introduction of our
plant, we can get a piece of cake in both countries.
3.4.4 Malaysia [6]
Malaysia has quite availability of hydrocarbon feedstock from oil and gas and the
acrylonitrile production in Malaysia is in the form of acrylonitrile-butadiene (ABS). There are
futures developments in the country where a petrochemical zone will be build and the
acrylonitrile production will be enhance. Malaysia has the investment contribution and technology
development where the acrylonitrile production can be enhance according to Industrial Master
Plan (IMP) 2006-2020. The new petrochemical zone in Malaysia is targeting to develop new
product and expand the manufacturing with the growth of the market size globally.
3.5 PRODUCT PRICING
Based on the Figure 3.5 below, the acrylonitrile price globally has its own trend and
mostly on every first quarter of each year it shows a good hike up and steady increase, and the
following of the year there are drop in the price trend and hike up again. The price trend was most
affected by weather factor and transportation. First quarter of the year seem the best weather
conditions and less transportation problem faced by the producer to deliver the product, so it
creates a higher prices trend with higher trade demand. In some circumstances, when the
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delivering of product challenge by the weather factor and transportation, the price goes down as
the demand of trade go slow on this period due to the risk of undeliverable material.
The price of acrylonitrile in year 2011 is higher than year 2012, this is due to the demandremain sluggish in Europe and United States.
Figure 3.4: Global Acrylonitrile Price Trend. [7]
3.6 CONCLUSIONFrom the reviewing of the market survey up to date, its stated clearly that production of
acrylonitrile in the Malaysia can shoot up the market over the Asian countries as the demand as
continual increment over year. The proposed acrylonitrile plant has production capacity of
120,000 tons per year which are wide enough to cover the demand supply. Based on the brighter
demand of acrylonitrile in Asia and its global market price as tend be an increment of 4%
annually gives the best financial outcome thus as schedules the acrylonitrile plant will be
commissioned within 2015 to 2016 in Malaysia.
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3.7 REFERENCES
[1] BP considers SEA acrylonitrile plant. Retrieved 31 October 2012, fromhttp://www.icis.com/Articles/2004/06/18/590273/bp-considers-sea-acrylonitrile-plant.html
[2] Chemical Insight and Forecasting: IHS Chemical. Retrieved 31 October 2012, from
http://www.ihs.com/products/chemical/planning/ceh/hydrogen-cyanide.aspx [3] 7th China International Acrylonitrile & Acrylic Fiber Forum. Retrieved 31 October 2012,
from http://www.fibre2fashion.com/news/fibre news/news details. aspx? news_id=81764.[4] Acrylonitrile Industry Outlook in India to 2016 Market Size, Company Share, Price Trends,
Capacity Forecasts of All Active and Planned Plants. Retrieved 31 October 2012, fromhttp://www.researchandmarkets.com/reports/2228353/acrylonitrile_industry _outlook_in_india_to_2016.
[5] Acrylonitrile Industry Outlook in Japan to 2016 - Market Size, Company Share, Price Trends,Capacity Forecasts of All Active and Planned Plants. Retrieved 31 October 2012, from
http://www.marketresearch.com/GlobalData-v3648/Acrylonitrile-Outlook-Japan-Size-Company-7126611. [6] The Malaysian Petrochemical Industry. Retrieved 31 October 2012, from
http://www.malaysia.ahk.de/fileadmin/ahk_malaysia/Market_reports/The_Malaysian_Petrochemical_Industry.pdf
[7] Global Indepth Acrylonitrile Analysis. Retrieved 31 October 2012, fromhttp://www.yarnsandfibers.com.
[8] Newswire, P. Acrylonitrile Global Market to 2020 - Household appliances and electronicssector to drive Acrylonitrile Butadiene Styrene (ABS) growth, polymeric applications propelPolyacrylonitrile demand from Asia-Pacific. (2012). Retrieved 8 December 2012, fromhttp://finance.yahoo.com/news/acrylonitrile-global-market-2020-household-123900271.html
[9] PCI , A.L.,. 2009
http://www.icis.com/Articles/2004/06/18/590273/bp-considers-sea-acrylonitrile-plant.htmlhttp://www.icis.com/Articles/2004/06/18/590273/bp-considers-sea-acrylonitrile-plant.htmlhttp://www.researchandmarkets.com/reports/2228353/acrylonitrile_industry%20_outlook_in_india_to_2016http://www.researchandmarkets.com/reports/2228353/acrylonitrile_industry%20_outlook_in_india_to_2016http://www.researchandmarkets.com/reports/2228353/acrylonitrile_industry%20_outlook_in_india_to_2016http://www.marketresearch.com/GlobalData-v3648/Acrylonitrile-Outlook-Japan-Size-Company-7126611http://www.marketresearch.com/GlobalData-v3648/Acrylonitrile-Outlook-Japan-Size-Company-7126611http://www.marketresearch.com/GlobalData-v3648/Acrylonitrile-Outlook-Japan-Size-Company-7126611http://www.malaysia.ahk.de/fileadmin/ahk_malaysia/Market_reports/The_Malaysian_Petrochemical_Industry.pdfhttp://www.malaysia.ahk.de/fileadmin/ahk_malaysia/Market_reports/The_Malaysian_Petrochemical_Industry.pdfhttp://www.malaysia.ahk.de/fileadmin/ahk_malaysia/Market_reports/The_Malaysian_Petrochemical_Industry.pdfhttp://www.yarnsandfibers.com/http://www.yarnsandfibers.com/http://finance.yahoo.com/news/acrylonitrile-global-market-2020-household-123900271.htmlhttp://finance.yahoo.com/news/acrylonitrile-global-market-2020-household-123900271.htmlhttp://finance.yahoo.com/news/acrylonitrile-global-market-2020-household-123900271.htmlhttp://www.yarnsandfibers.com/http://www.malaysia.ahk.de/fileadmin/ahk_malaysia/Market_reports/The_Malaysian_Petrochemical_Industry.pdfhttp://www.malaysia.ahk.de/fileadmin/ahk_malaysia/Market_reports/The_Malaysian_Petrochemical_Industry.pdfhttp://www.marketresearch.com/GlobalData-v3648/Acrylonitrile-Outlook-Japan-Size-Company-7126611http://www.marketresearch.com/GlobalData-v3648/Acrylonitrile-Outlook-Japan-Size-Company-7126611http://www.researchandmarkets.com/reports/2228353/acrylonitrile_industry%20_outlook_in_india_to_2016http://www.researchandmarkets.com/reports/2228353/acrylonitrile_industry%20_outlook_in_india_to_2016http://www.icis.com/Articles/2004/06/18/590273/bp-considers-sea-acrylonitrile-plant.html -
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CHAPTER 4 TECHNOLOGY PROCESS ROUTES
There are plenty of process routes available for the cracking process to produce olefin
such as propylene; also to produce acrylonitrile. In this chapter, discussion on the steam cracking
and fluid catalytic cracking is performed in section 4.1, whereas section 4.2 is the comparison onthe propylene ammoxidation and propane ammoxidation.
4.1 PROPYLENE PRODUCTION
For the production of propylene from the light naphtha feedstock after the hydro-treating
plant, the common cracking processes are steam cracking and fluid catalytic cracking.
Cracking processes carry out chemical reactions that fracture or crack the large, high-
boiling hydrocarbon molecules into smaller and lighter molecules, which are suitable for further
processing. There are several cracking unit such as steam cracking, fluid catalytic cracking and
hydrocracking.[1] However, two primary interest cracking units will be discussed further in this
report which is steam cracking unit and fluid catalytic cracking unit.
4.1.1 Steam Cracking
Steam cracking is mainly afree radical reaction which generates C2 components. There
is no catalyst needed in the steam cracking process. Without the presence of the catalyst, high
reaction temperature is thus required, which is at 750-850C [2]. Besides, propylene content of C3
stream is about 50%.[3]
4.1.2 Fluid Catalytic Cracking (FCC)
The catalytic cracking is where -scission occurs under the existence of catalyst cracking
through carbocation intermediate.[4] Carbocation is longer lived and more selective than free
radical.[4]
High yields of C3, C4 olefins can be obtained such that propylene content of C3 streamis about 70%.[3]
Catalytic cracking breaks complex hydrocarbons into simpler molecules in order to
increase the quality and quantity of lighter , more desirable products and decrease the
amount of residuals . Use of a catalyst in the cracking reactionincreases the yield of improved-
quality products under much less severe operating conditions than in thermal cracking, for
example reaction temperature in the range of 454.44-510C [5] The catalysts used are typically
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solid materials (zeolite, aluminium hydrosilicate, treated bentonite clay, fullers earth, bauxite,
and silica-aluminium) that come in the form of powders or beads.[5]
On the other hands, the good sides, bad sides and the solutions of the drawback are discussed
in the Table 2 below.
Table 4.1: Comparison of the good sides and bad sides of the steam cracking and catalytic
cracking processes.
STEAM CRACKING CATALYTIC CRACKING ADVANTAGES
High yield with high temperature inthe cracking furnaces.[2]
Produces high-octane gasoline and fueloils. [4]
The process is stable, flexible andunder control both for liquid and gasfeeds. [2]
Reduce formation of olefinic hydrocarbons, which form gum deposits ingasoline.[1]
Proper control valve performance infurnace improves the accuracy ofthroughput control to the plant performance.[2]
Produce hydrocarbons with high anti-knock properties . [1]
Better selectivity .Effect of the catalyst, which promotesisomerisation and dehydrocyclization
reactions .[4]
Reduce formation of methane and C2 hydrocarbon gases in favour of C3 and C4 hydrocarbons used in LPG.[1]
DISADVANTAGESFurnace is operated at very hightemperature and pressure compared toFCC.
Nitrogen compounds are readily adsorbedon the catalyst acid sites and causedeactivation .[4]
Lower yield of propylene. Polycyclic aromatics and asphaltenescontribute strongly to coke formation . Itrequires regeneration of the catalyst.[4] Coke formation on catalyst is substantiallyreduces its activity and producesgasolinesof lower quality . [4]
SOLUTIONSFeedstocks are often pretreated todecrease the metallic and asphaltenecontents. [4] Hydrotreatment , solvent extraction and propane deasphalting are important
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treatment processes.Modification of the composition andmicroporous structure ofcatalyst or addingmetals like Sb, Bi or Sn or Sb-Sn
combination.[4]
4.1.3 Decision Making
Accordingly, with regards to increasing propylene production, it is more advantages to
have a catalytic cracking-type reaction than a steam cracking type reaction.[6] Based on the table
2, FCC is advantageous than steam cracking. The main reason is that FCC gives high yield of
propylene which is the desired feedstock for acrylonitrile production. By using appropriate
catalyst, lower operating temperature and pressure are required compared with steam cracking.
Although coking deposition on the catalyst may decrease the catalytic activity, but there is
regenerator installed to regenerate the catalyst and remove the coke.
4.1.4 References[1] An introduction to petroleum refining and the production of ultra low sulphur gasoline and
diesel fuel. The international council on clean transportation. Retrieved 9 October 2012, fromwww. Mathproinc.com
[2]Steam cracking furnaces. Retrieved 28 September 2012, fromhttp://valveproducts.metso.com/neles/ApplicationReports/2722_Petrochemical/2722_01_08en.pdf
[3]PERP Program- Propylene. Retrieved 9 October 2012, fromhttp://www.chemsystems.com/about/cs/news/items/PERP%200607_3_Propylene.cfm
[4] S. Matar & L.F. Hatch. (1994). Provides quick and easy access to hundreds of reactions, processes and products. Chemistry of petrochemical processes. Second eds. United States ofAmerica: Gulf Publishing Company.
[5] Cracking. The Encyclopedia of Earth. Retrieved 28 September 2012, fromhttp://www.eoearth.org/article/Cracking
[6] Kitaminato-machi, Wakamatsu-ku & Kitakyushu-shi. More Propylene in FCC Units. CatalystResearch Center. JGC Catalysts and Chemicals Ltd.
http://valveproducts.metso.com/neles/ApplicationReports/2722_Petrochemical/2722_01_08en.pdfhttp://valveproducts.metso.com/neles/ApplicationReports/2722_Petrochemical/2722_01_08en.pdfhttp://valveproducts.metso.com/neles/ApplicationReports/2722_Petrochemical/2722_01_08en.pdfhttp://www.chemsystems.com/about/cs/news/items/PERP%200607_3_Propylene.cfmhttp://www.chemsystems.com/about/cs/news/items/PERP%200607_3_Propylene.cfmhttp://www.eoearth.org/article/Crackinghttp://www.eoearth.org/article/Crackinghttp://www.eoearth.org/article/Crackinghttp://www.chemsystems.com/about/cs/news/items/PERP%200607_3_Propylene.cfmhttp://valveproducts.metso.com/neles/ApplicationReports/2722_Petrochemical/2722_01_08en.pdfhttp://valveproducts.metso.com/neles/ApplicationReports/2722_Petrochemical/2722_01_08en.pdf -
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4.2 ACRYLONITRILE PRODUCTION
4.2.1 Propylene Ammoxidation
Propylene ammoxidation is a process in which mixtures of propylene, ammonia, and
oxygen are converted in the presence of a catalyst, with acrylonitrile as its primary product. It isalso known as ammonoxidation oroxyamination.[1]
The catalyst selected for propylene ammoxidation should be multifunctional and possesses redox
properties. Among commonly employed catalyst contains molybdenum or antimonium oxides
mixed with transition metals, such as Ferum, Nickel, Copper and Vanadium, and activated by
alkali and rare earth elements.[2] Table 4.2 below summarized the advantages and disadvantages
of propylene ammoxidation.
Table 4.2 : Advantages and disadvantages of propylene ammoxidation.
Advantages Disadvantages
1. The reaction rate is higher.[2] 1. Raw material price much expensive than propane. (50% of differences).[3]
2. Less cost required in operation becausethere is no need for excess ammonia andH2SO4 that is required for ammonianeutralization.
2. Productivity levels are comparable tothose obtained with propane.[3]
3. Lower capital cost for wastewaterdisposal.
3.The co-products formation, such asacetonitrile (ACN) and hydrogencyanide (HCN) are minimized, whichwould have a high value in the chemicalmarket.[3]
4. Adsorption rate of propylene is 10 times bigger than propane.
4. Risk of propylene shortage due to itsincreasing consumption and worldwidedemand of nitriles and other derived products.[3]
5. The reaction conditions to activate C-H bond in propylene are less energydemanding, thus has a positive effect onselectivity.[2]
6. Alkene activation is easy and does notrequires severe operating conditions, because they have a high reactivity.[3]
7. Does not necessarily needs a very active,selective and stable catalysts.[3]
8. Products are generally more stable thanreactants, and they are not easily
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decomposed during the reaction, thus preventing the formation of undesirableoxygenated C and N compounds.[3]
4.2. 2 Propane AmmoxidationProduction of acrylonitrile by propane ammoxidation is a conventional process. By this
reaction route, maximum yield and selectivity of 60 to 80 and 40%-50%[4] can be obtained.
Propane ammoxidation has a high-conversion (>90%) propane reaction with a yield of 60%
acrylonitrile with the aid of mixed metal oxide catalyst which are environmental friendly. Below
are the advantages and disadvantage as shown in table 4.3.
Table 4.3: Advantages and disadvantages of propane ammoxidation.Advantages Disadvantages1. Propane costs were lower than
propylene( 30% less than propylene price).[5]
1. By using propane, need higher costs forexcess ammonia and H2SO4 required forammonia neutralization.
2. Capital savings (decrease productioncosts by 20%).[6] 2.
Higher capital for waste-water disposal.
3. Productivity levels comparable to
those obtained with propylene.
3. Alkane activation(limiting step) leaddifficult and requires severe operating
conditions and very active, selective andstable catalysts.
4. Operation temperatures not higherthan 500C.
4. Products are less stable than reactants andthey can be easily decomposed during thereaction leading to the formation ofundesirable oxygenated C and Ncompounds. [7]
5. Maximize co-products formation,such as acetonitrile (ACN) andhydrogen cyanide (HCN) - high valuein the chemical market.
5. The adsorption rate of propane is near 10times smaller than that of propylene.[7]
6. The reaction conditions to activate the C-H bond in propane are more energydemanding, which has a negative effecton selectivity.
7. The low activity of propane has also ledto the use of gas-phase additives (e.g.,H2S or CH3Br) as radical generators(environmental concerns do not makethis option attractive).
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4.2.3 Decision Making
In summary, the process route selection should be done according to feasibility in term of
economic, environment and also technical. By having this as consideration, propylene
ammoxidation is the most convenient because the technicality of practicing it has a worldwideacceptance over acrylonitrile producer. Propylene ammoxidation with the best catalyst are able to
yields 80-82% of acrylonitrile and the reaction rate is high enough to achieve almost total per-
pass conversion at ratios of reactants close to stoichiometry. Economic wise, this process route
has advantages on the saving operational cost which minimize wastewater treatment and enhance
by the value added of the by products produced. Some processes upset were also faced due to
inappropriate catalyst consumption and need more sophisticated handling of catalyst. By having
greener and economic choice, propylene ammoxidation is the right option for the production of
the acrylonitrile.
4.2.4 References
[1] Dictionary, T.F., Ammoxidation. (2003). Retrieved on 12 November, fromhttp://encyclopedia2.thefreedictionary.com/ammoxidation
[2] Florea, M., Silvy,R. P, Grange, P., Inuence of the reaction conditions on the activity properties of vanadium aluminiumoxynitride propane ammoxidation catalyst. (2003).Retrieved on 12 November, from http://144.206.159.178/ft/53/202391/14404315.pdf
[3] Florea, M., Silvy,R.P, Grange P., Vanadium Based Catalysts for Propane ammoxidationreaction. (2008). Retrieved on 12 November, fromhttp://gwchimie.math.unibuc.ro/anunivch/20051/AUBCh2005XIV14956.pdf
[4] Bowswell., C, (1999.The technology Frontier: Alkane Activation Chemical Market Reporter,20.
[5] Kinetics and reaction network in propane ammoxidation to acrylonitrile on vanadium-antimony-aluminum based mixed oxides.Research Article. Publication Date: January 1992
[6] Grasselli, R. K. In Handbook in Catalysis; Ertl, et al., Eds.; Wiley-VCH: Weinheim, Germany,
1997; Vol. V, p 2302.[7] Bowker, M.; Bicknell, C. R.; Kerwin, P. Appl. Catal., A( 1997).PropaneAmmoxidationTechnology. Journal of Chem , 159 136-205.
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CHAPTER 5: PROCESS DESCRIPTION
This report is about RAPID project, which mean the integration processes of the refinery
to the end petrochemical product will be covered. In this report, the production of acrylonitrile
from sour crude oil will be discussed. The processes are covered four important plants, which areRefinery Unit, Hydro-treating Unit, Fluid Catalytic Cracking (FCC) unit and Acrylonitrile
Production Unit. Detail process description of the four plants will be delivered with their specific
operating conditions. The simulation of the process for the four plants has been performed in
Aspen Plus and detailed Process Flow Diagram has been drawn by using Microsoft Visio 2010.
5.1 PLANT UNIT 1: REFINERY PROCESS DESCRIPTION
5.1.1 IntroductionSour crude oil, which is Basra oil from Iraq is chosen as raw material for refinery plant.
As sour crude oil contains thousands of complex components and contaminants, a refinery plant is
usually the heart of well-integrated RAPID project with extensive downstream processes as well.
The typical refinery plant is made up of 500-900 acres with more than over 500 pieces of
equipments and tools, such as reactors, stripping column, atmospheric distillation column,
desalter, pump, compressor and accumulator. This section will cover the process flow of the
proposed 150,000 barrels per day (bpd) of sour crude oil.
5.1.2 Crude oil (Feedstock) Storage and Inventory
As discussed in the section 2.1,the Basra oil feedstock availability is stable and reliable
for the future coming years.It has been decided that a feedstock inventory of 45 days will be
sufficient to counter market fluctuation of feedstock supply. This translates to an additional figure
of 1331,325 metric tons of crude oil stored onsite (or 13.4% of the annual feedstock required).
The amount of inventory should be reviewed and adjusted at the end of each operating year as a
representation of the markets supply volatility. As a point, a smaller inventory is favorable as it
reduces the overall operating risk of the plant. However, this must be balanced out with the
reliability of continuous production.
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5.1.3 Process Description
(1) Desalting Section
As the raw crude oil arriving contains quite a bit of water and salt, it is normally sent for
salt removing first, in a piece of equipment called a desalter. Raw sour crude oil usually containssignificant amount of water, inorganic salts, suspended solids, and water-soluble trace metals. In
refining process, the first step is to reduce these contaminants by desalting (dehydration) so that
corrosion, plugging, and fouling of equipment can be avoided and also to prevent poisoning the
catalysts in the processing units.
Sodium, calcium and magnesium chlorides (NaCl, CaCl2 and MgCl2) are frequently
found in crude oil. Presence of these compounds in crude oil can cause several problems in the
refining processes, this is because all those salts are hydrolysable at temperatures above 120
0
C.Upon hydrolysis, the chlorides get converted into hydrochloric acid, which will find its way to the
distillation column's overhead where it will corrode the overhead condensers. A good performing
desalter can remove about 90% of the salt in raw crude.
Intense mixing takes place over a mixing valve and (optionally) as static mixer. The
desalter, a large liquid full vessel, uses an electric field to separate the crude from the water
droplets. It operates best at 120 - 1500C, hence it is conveniently placed before the preheat train.
Desalting units remove contaminants from crude oil by washing water. After the oil is washed andmixed, demulsifying chemicals are added and then the electrostatic fields are used to break the
emulsion. About 2 7% wash water is added to the oil as an extraction agent. Desalter effluent is a
combination of many things such as: brine washing water used for removing salt, sand and mud
washing water jet used at periodic intervals, connate water produced from the reservoir with crude
oil. Desalters wastewater contains oil, demulsifier, and oxygen scavenger [2].
(2) Pre-Flashing Section
Downstream the desalter, crude is firstly heated up a piece of equipment, named as 'pre-
flash vessel', at about 170C -200 C, and pressure about 2 - 5 barg, where the vapours are
separated from the remaining liquid. Vapours are directly sent to the atmospheric distillation
column, and by doing so, the hydraulic load on the remainder of the crude preheats train and
furnace is reduced, resulting in smaller piping and pumps required.
Just upstream the pre-flash vessel, a small caustic stream is mixed with the crude, in order
to neutralize any hydrochloric acid formed by hydrolysis. The sodium chloride formed will leave
the atmospheric distillation column via the bottom residue stream. The dosing rate of caustic is
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adjusted based on chloride measurements in the overhead vessel, which is typically around 10 -
20 ppm [3].
(3) Heat Exchanger Network (HEN) & FurnaceAfter being heated up by pre-flash vessel, the crude needs to be heated up more before
entering the atmospheric distillation column and this is done at first in a series of heat exchangers
where heat is taken from other process streams which require cooling before being sent to
rundown. Heat is also exchanged against condensing streams from the main column. Typically,
the crude will be heated up in this way up to a temperature of 200C - 280 C[3], before entering a
furnace.
At about 200 C - 280 C, the crude enters the furnace where it is heated up further to
about 330 C-370 C. The furnace outlet stream is sent directly to the atmospheric distillation
column. Here, it is separated into a number of fractions, each having a particular boiling range.
(4) Physical Separation: Atmospheric Distillation Unit (ADU)
Distillation is the crucial step in the processing of crude oil and it takes place in a tall steel
tower called a atmospheric distillation column. The inside of the column is divided at intervals by
horizontal trays. The column is kept very hot at the bottom (but as different hydrocarbons boil at
different temperatures, the temperature gradually reduces towards the top, so that each tray is a
little cooler than the one below. The column is designed to be insulated in order to minimize heat
loss to the environment, hence energy saving can be achieved.
Most of the fractions in the crude oil vaporize and rise up the column through perforations
in the trays, losing heat as they rise. When each fraction reaches the tray where the temperature is
just below its own boiling point, it condenses and changes back into liquid phase. A continuous
liquid phase is flowing by gravity through 'downcomers' from tray to tray downwards. In this way,
the different fractions are gradually separated from each other on the trays of the fractionationcolumn. The heaviest fractions condense on the lower trays and the lighter fractions condense on
the trays higher up in the column. At different elevations in the column, with special trays called
draw-off trays, fractions can be drawn out on gravity through pipes, for further processing in the
refinery.
At top of the column, vapours leave through a pipe and are routed to an overhead
condenser, typically cooled by air fin-fans. At the outlet of the overhead condensers, at
temperature about 400C, a mixture of gas, and liquid naphtha exists, which is falling into an
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overhead accumulator. Gases are routed to a compressor for further recovery of LPG (C3/C4),
while the light naphtha is pumped to a hydrotreating unit for sulfur removal.
An atmospheric distillation column needs a flow of condensing liquid downwards in order
to provide a driving force for separation between light and heavy fractions. At the top of thecolumn this liquid flow is provided by pumping a stream back from the overhead accumulator
into the column. Unfortunately, a lot of the heat provided by the furnace to vaporise hydrocarbons
is lost against ambient air in the overhead fin-fan coolers. A clever way of preventing this heat
lost of condensing hydrocarbons is done via the circulating refluxes of the column. In a
circulating reflux, a hot side draw-off from the column is pumped through a series of heat
exchangers, where the stream is cooled down. The cool stream is sent back into the column at a
higher elevation, where it is been brought in contact with hotter rising vapours. This provides an
internal condensing mechanism inside the column, in a similar way as the top reflux does which is
sent back from the overhead accumulator. The main objective of a circulating reflux therefore is
to recover heat from condensing vapours. An atmospheric distillation column will have several
(typically three) of such refluxes[3], each providing sufficient liquid flow down the corresponding
section of the column. An additional advantage of having circulating refluxes is that it will reduce
the vapour load when going upwards in the column. This provided the opportunity to have a
smaller column diameter for top sections of the tower. Such a reduction in diameter is called a
'swage'.
The lightest side draw-off from the atmospheric distillation column is a fraction called
kerosene, boiling in the range 160 - 2800C, which falls down through a pipe into a smaller
column called 'side-stripper'. The purpose of the side stripper is to remove very light
hydrocarbons by using steam injection or an external heater called 'reboiler'. The stripping steam
rate is controlled such as to meet the flashpoint specification of the product. Similarly to the
atmospheric column, the side stripper has fractionating trays for providing contact between
vapour and liquid. The vapours produced from the top of the side stripper are routed back via pipe
into the fractionating column[3].
The second and third (optional) side draw-offs from the main fractionating column are
gasoil fractions, boiling in the range 200 - 4000C, which are ultimately used for blending the final
diesel product. Similar as with the kerosene product, the gasoil fractions (light and heavy gasoil)
are first sent to a side stripper before being routed to further treating units.
At the bottom of the atmospheric distillation column, a heavy and black coloured fraction
called residue is drawn off. In order to strip all light hydrocarbons from this fraction properly, the
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bottom section of the column is equipped with a set of stripping trays, which are operated by
injecting some stripping steam (1 - 3% on bottom product) into the bottom of the column. The
atmospheric residue will further send to vacuum distillation column to undergo separation and
purification.
*Vacuum distillation process will be excluded in our plant due to time constraints and non-
related to our final product- Acrylonitrile.
5.1.4 REFERENCES
[1] Wall Street Journal, W.Shell & Petronas To Start Drilling At Iraq Majnoon Oil Field In July .
(2012). Retrieved 30 October 2012, from http://articlesofinterest-kelley.blogspot.com/2011/03/iraq-oil-shell-to-start-drilling-at.html. [2] Pak, A., Mohammadi, Toraj,Wastewater treatment of desalting units. Desalination, 2008.
222 (1 3): p. 249-254.[3] Haslego, C., Refinery-Process-Description. The Chemical Engineer's Resources
5.2 PLANT UNIT 2: HYDRO-TREATING PROCESS DESCRIPTION
5.2.1 Introduction
Hydrodesulphurization unit in the plant are responsible for the removal of sulphur as primary target and also other contaminants such nitrogen, heavy metals, saturated olefins and
potential of aromatics from light naphtha. Sulphur needed to be removing through
hydrodesulphurization because it can lead of corrosion of metal and upset the processes of the raw
material ahead. The light naphtha is feed at 20170 kg/hr through the hydrodesulphurization unit
with initial sulphur content about 0.05% and produces desulphurized light naphtha with sulphur
content less than 5ppmw. The sulphur are removed and captured as hydrogen sulphide.
5.2.2 Process Description
(1) Pre-Heater and Furnace [1][2][3]
The light naphtha from the refinery is then combined with the hydrogen stream (recycle
hydrogen and hydrogen feed) in excess to optimize the desulfurization process. The resulting
liquid-gas mixture is preheated through heat exchanger which has it hot stream of reactor outlet
stream. The stream is then passed through furnace and further heated to a temperature of 598.15 K.
http://articlesofinterest-kelley.blogspot.com/2011/03/iraq-oil-shell-to-start-drilling-at.htmlhttp://articlesofinterest-kelley.blogspot.com/2011/03/iraq-oil-shell-to-start-drilling-at.htmlhttp://articlesofinterest-kelley.blogspot.com/2011/03/iraq-oil-shell-to-start-drilling-at.htmlhttp://articlesofinterest-kelley.blogspot.com/2011/03/iraq-oil-shell-to-start-drilling-at.htmlhttp://articlesofinterest-kelley.blogspot.com/2011/03/iraq-oil-shell-to-start-drilling-at.html -
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(2) Hydrodesulfurization Reactor [4][5]
Hydrodesulfurization process is carried out by a fixed bed reactor with the aid of catalyst
of cobalt/nickel-molybedenum. The heated stream is passed through the reactor and hydro
treating process begins to happen when hydrogen form saturated compound, namely hydrogensulphide by reacting with unsaturated hydrocarbon. The catalyst bed in the reactor is capable to
remove trace of metals and other heavy solids through their packing. This process is described by
this reaction:
Hydrocarbon-S + H2 Hydrocarbon + H 2S
This process has a high conversion of hydrogen sulphide at about 90%. The reactor runs at
temperature of 598.15 K and pressure of 2026.5 kPa to ensure the partial pressure of hydrogen are
sufficient to desulfurize the light naphtha. Due exothermic reaction in the reactor, it lead to a hot
product stream and partially cooled by flowing through heat exchanger.
(3) Naphtha Stripper [6][7]
The purpose of introducing stripping unit is to remove the desulphurized naphtha from the
excess hydrogen and hydrogen sulphide. The operating temperature of the stripper is affected on
the bubble point of desulphurized naphtha. The partially cooled product stream from the reactor is
further cool in the cooler to a temperature of 328.15 K .The reduce in temperature lead the
condensation of desulfurized naphtha thus the sour gasses are removed by providing heat through
the steam reboiler at 474.15K. The condenses reflux at 323.15K where desulphurized naphtha
form liquid and remove to bottom to further process at fluid catalytic cracking unit. The vapour
form are primarily sour gasses are removed as top product of the stripper
(4) Amine Absorber [8]
The amine treating unit removes carbon dioxide (process gas) and hydrogen sulfide from
the sour gas and also remove trace amount of hydrocarbon. The amine (methyl-diethanolamine-MDEA) is regenerate and recycled in this treating unit. MDEA has a low absorption of carbon
dioxide and high absorption of hydrogen sulfide, this encourage a complete absorption of
hydrogen sulfide from sour gas.
The feed sour gas stream from the stripper enters the bottom of amine absorber, while the cooled
lean amine entered the top of the absorber. The feed sour gas flows upward counter-current to the
lean amine solution. Rich amine solution with acid gases leaves the bottom of absorber at elevated
temperature, due to exothermic absorption reaction.From the top of the absorber, the hydrogen is
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removed as sweet gas and then compressed through compressor as a recycle stream where it
combine with hydrogen make up stream.
(5) Amine Surge DrumThe rich amine stream from the bottom of amine absorber then further to amine surge
drums and allow separation of hydrocarbon from the amine solution. This surge drum serves as an
separation for the hydrocarbon where flare system were attached for safety reason. The
hydrocarbon that has been removed from the rich amine stream might be in vapour or liquid phase.
The liquid phase are remove with a flow rate less than 10kg/hr and vapour are passed through to
flare system where it will be burnt out.
(6) Amine Regenerator [9]
The amine solution is regenerate and striping of hydrogen sulfide and carbon dioxide takes
place. Amine regenerator reboiler supply heat to strip hydrogen sulfide and carbon dioxide from
the rich amine by using steam as heating medium. The rich amine stream from the amine surge
drum is passing through heat exchanger to be preheated before being feed into amine regenerator.
The heat supply by the reboiler steam lead to partial pressure of hydrogen sulphide in the amine
drop and enhance the driving force of the hydrogen sulphide gasses move away from the amine.
Hydrogen sulphide (acid gasses) vapour leaving the top of the amine generator is cooled in the
overhead condenser. The mixture of gasses and condensed liquid stream is passed through reflux
accumulator. The accumulator separates the uncondensed gas (acid gas) and trace amount of
water will be removed. Condensate (lean amine) is pump back to the amine regenerator through
reflux pumps. The lean amine from the amine regenerator is cooled in the heat exchanger and
further cooled in the cooler before entering the absorber. Amine make-up stream available for the
quick recover of amine for the case of loses happen in the amine regenerator.[1]
5.2.3 References
[1] Law D. (August, 1994)."New MDEA Design in Gas Plant Improves Sweetening, ReducesCO2," Oil & Gas Journal, Vol. 92, (No35), p. 83.
[2]Distillation Process for Light Gas Oil Hydrodesulfurization., ChemicalEngineeringandProcessing , 43(2004), pp1309-1326.
[3] Hou, W., SU, H., HU, Y., CHU, J., Modeling, Simulation and Optimization of aWholeIndustrial Catalytic Naphtha Reforming Process on Aspen Plus Platform.,Chinese Journal ofChemical engineering, Volume 14, Issue 5, October 2006,Pages 584-591.
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[4] Revamp of NHT&Platformer Unit., Tehran North Refinery, Process Data Book,Volume 1,October 2003, AxensCompany.
[5] Breivik, R., Egebjerg, R.: Novel Coker Naphtha Hydrotreating Technology, ERTC 12thAnnual Meeting, Barcelona, 19 November, 2007.
[6] A.Lengyel, S.Magyar, J.Hancsk. Upgrading of Delayed Coker Light Naphtha in a Crude oilRefinery, Petroleun& Coal Journal, Vol.51(2) p.80-90(2009).[7] S.Sadighi, S.R.S.Mohaddecy, O.Ghabouli, M.Bahmani.Revamp Of Naphtha Hydrotreating
Process In An Iranian Refinery, Petroleun& Coal Journal, Vol.51(1) p.45-50(2009).[8] Abry, R.G.F., and M.S. Dupart, "Amine Plant Troubleshooting and Optimization,"
Hydrocarbon Processing, Vol.74, (No. 4), p. 41 (April, 1995).[9] Bullin, J.A., J.C., Polasek, and J.W. Holmes, "Optimization of New and Existing Amine Gas
Sweetening Plants by Computer Simulation," Proceedings of the 60th GPA AnnualConvention, p. 142 (1981).
5.3PLANT UNIT 3: FLUID CATALYTIC CRACKING (FCC) PROCESS DESCRIPTION
5.3.1 Introduction
Fluid Catalytic Cracking (FCC) has been chosen instead steam cracking because it is ableto produce more gasoline with higher octane and less heavy fuel oils and light gases. In this process plant, high yield of propylene is achieved by using the SAPO-11 catalyst in the crackingreaction, not only that, operating condition of the reactor also been lowered. The high yield of propylene is favourable as it is the feedstock for the acrylonitrile production. There are basicallythree main unit for the FCC plant, which is reactor-regenerator unit, gas membrane separation unitand distillation column purification unit.
5.3.2 Process Description
(1) Feedstocks to the Reactor (R-02)
There are two streams fed into the reactor (R-02) for undergoing the cracking reaction.The main stream, which is the light naphtha came from the hydro-treating plant and one recyclestream came out from the final distillation column which contains the 99.9% purity of butane.
(a) The light naphtha from hydro-treating plant is the desulphurized light naphtha, whichconsisting the eight components with a negligible small amount of sulphur (less than0.5ppmw). The list of the components of light naphtha and its mole fraction percentage isshown in Table 1 below.
Table 5.1: Light naphtha composition from the hydro-treating plant. [1]
Components Mole fraction (%)n-Pentane 18.71iso-Pentane 9.82n-Hexane 17.05iso-Hexane 19.39
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Cyclopentane 6.45Methylcyclopentane 13.27Cyclohexane 9.44Benzene 5.87Total 100.00
The light naphtha stream (Stream Number 58) has the mass flow rate of about 18,358 kg/hr at474.15 K and 1013.25 kPa. Since the reactor operates at 872 K and 340 kPa, the light naphthastream (58) is passing through a turbine (P-12) to drive the relieved pressure to achieve thestream (82) at 360 kPa. The power generated is sent to the power regeneration plant thatcould be used in this FCC plant. After that, stream (83) gains the heat up to 673.15 K throughthe heat exchanger (Hx-08). The stream (83) is now at 673.15 K and 360 kPa in gas phase.
(b) Recycle stream came out from the final distillation column which contains the 99.9%purity of butene.The bottom stream (99) of the final distillation column contains 99.9% purity of butane at
285.4 K and 200 kPa. The stream (99) passes through a pump (P-16) to increase the pressureto 360 kPa. Then, stream (100) passes through a heat exchanger (Hx-09) to gain heat up to500 K. However, it (stream 101) is not yet satisfies the requirement operating temperature ofthe reactor. Thus, another back-up boiler (B-01) is used to heat up the stream (102) up to 872K and it is in gas phase.
Both the stream (83) and (102) are the light naphtha and butene streams respectively, are
being mixed in a mixer (M-02) and fed into the riser of the reactor (R-02).(2) Reactor (R-02)
2.1 Riser, Riser Termination Device (RTD) and Cyclone
The light naphtha (83) and recycle butene (102) are fed into the riser together with acontrolled amount of regenerated catalyst. At the same time, the hot generated catalyst vaporizesthe feed, hence thecracking process begins . The endothermic reaction takes place in the riserwith the residence time of 2-10s at 872 K and 340 kPa. [2] The resultant vapors carry the catalystupward through the riser. At the top of the riser, the desired cracking reactions are completed, andthe catalyst is quickly separated from the hydrocarbon vapors to minimize secondary reactions.There is a riser termination device (RTD) used to turn the catalyst direction downward .Besides, a cyclone separation unit is installed at the upper part of the reactor and it is used toseparate the catalyst from the vapor product.
2.2 Stripping Section and Baffles
In additional, the catalyst-hydrocarbon mixture flows back in the disengaging zone.Stripping steam is injected into the bottom of the reactor where there is astripper section .Stripping stream, at a rate of2 kg to 5 kg per 1000 kg circulate catalyst is primarily used toremove the entrained hydrocarbons between catalyst particles. The stream used has superficial
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velocity of 0.75 ft/sec (0.23 m/sec).[3] The oil is removed from the catalyst with the help ofsome baffles installed in the stripper. After that, thespent catalyst is sent to the regenerator through a standpipe.
(3) Regenerator (RG-01)
3.1 Coke Formation and Catalyst Regeneration
The coke deposited on the spent catalyst which is produced in the cracking reaction,isburned off in the regenerator at 943.15 K and 700 kPa by introducing excess air to ensure theefficient combustion of coke. The spent catalyst entering the regenerator contains between0.4 wt%and 2.5 wt% coke , depending on the quality of the feedstock. Components of coke are carbon,hydrogen and trace amounts of sulfur and nitrogen. This burn according to the following reactions:[3]
C + O2 COCO + O2 CO2 C + O2 CO2 H2 + O2 H2OS + xO SOx N + xO NOx
Air provides oxygen for the combustion of coke and is supplied by one or more air blowers. The air blower provides sufficient air velocity and pressure to maintain the catalyst bedin a fluid state. The air enters the regenerator through an air distributor located near the bottom ofthe vessel. The air distributor is important in achieving efficient and reliable catalyst regeneration.During regeneration, the coke level on the catalyst is typically reduced to 0.05%.[3]
3.2 Two-Stage Cyclones
There is a high efficiency two-stage cyclones separator used to separate the remainingcatalyst from the hot flue gas. After that, thehot flue gas produced will be exiting at the top ofthe regenerator. The hot flue gas contains carbon dioxide, carbon monoxide, water and excess airat the regenerator temperature. Therefore, thehot flue gases are sent to the power recovery unitto produce superheated steam.
3.3 Standpipe/ Slide Valve
From the regenerator, the regenerated catalyst flows down a transfer line which is aregenerator standpipe. The standpipe provides the necessary pressure to circulate thecatalyst around the FCC unit. A slide valve is used to regulate the flow rate of the regeneratedcatalyst to the riser. Its main function isto supply enough catalyst to heat the feed and achievethe desired reactor temperature . The regenerated catalyst flow is mainly controlled byadjusting the pressure differential between the reactor and regenerator.
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(4) MFI Zeolite Membrane (Remove H 2)
The vapor stream (89) is produced from the catalytic cracking reaction which containingthe around 77% of propylene, 5% of ethylene, 14% of butene and 2% of hydrogen. This stream isfurther purified by using MFI zeolite membrane and subsequently two distillation columns inorder to get the highest purity of propylene. The operating conditions for theMFI (Mordeniteframework inverted) zeolite membrane is at 773.15 K and 168 kPa. [5] Therefore, stream (89)which is at 872 K and 340 kPa needs to be cooled down and reduced pressure to achieve thedesired temperature and pressure. The pump (P-14) is used to relief the unwanted pressure and theheat exchanger (Hx-09) is used to exchange the unwanted heat to another stream. The pressurerelieved is used to drive a turbine for the power generation network that could be used in this FCC plant.
Based on few literature reviews,Dong J. et. al. has concluded that at high temperatures
(500
C or 773.15 K), the MFI zeolite membrane becomes permselective for hydrocarbon overhydrogen. [5] Besides, Pan M. et. al. has concluded that the secondary-grown MFI zeolitemembrane prepared with template is impermeable to C3 and C4 hydrocarbons.[6] Based on SigmaAldrich, the crtical diameter of the molecules of hydrogen, propylene, ethylene and butene are 2.4, 5 , 4.2 and 5.1 respectively. Obviously, the molecule size for hydrogen is smaller thanall the propylene, ethylene and butene molecules. Therefore, an assumption is made, saying thatabout 99.9% of hydrogen is being permeated through the MFI zeolite membrane over the propylene, ethylene and butene. The stream (92) contains the99.9% purity of hydrogen sent tohydrotreating plant for the process use. All the propylene, ethylene and butene are sent for further purification unit.
(5) Distillation Column I (Remove Ethylene)
The retentate, stream (93) is sent for further purification by using two distillation columns.Before that, stream (93) passes through pump (P-15) to increase pressure from 168 kPa to 1800kPa. Then, stream (94) passes through heat exchanger (Hx-08) to be removed the heat and cooleddown to 298.15 K. Stream (95) enters the first distillation column at the 8th feed stage. Theoperating condition of the first distillation column (D-02) is tabulated in the Table 3 below. Theupper stream (96) comes out with 99.6% purity of ethylene at 245.3K and 1800 kPa in gas phase,which is then stored and sold. The bottom stream (97) comes out from the D-02 will then entersanother distillation column to achieve the desire purity of the desired product, which is propylene.
Table 5.2: Requirement conditions of the first distillation column (D-02).
Distillation Column1 (D-02) Number of stages 56
Feed stage 8Reflux ratio 0.99
Distillate to feed mole ratio 0.242Condenser type Partial
Condenser Pressure 18 barReboiler Pressure 12 bar
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(6) Distillation Column II (Remove Butene)
Stream (97) enters the second distillation column (D-03) at the 8th feed stage. Theoperating condition of the second distillation column (D-03) is tabulated in the Table 4 below.The upper stream (98) comes out with the desired product of97.6% purity of propylene at 289.5K and 850 kPa. Whereas, the bottom stream (99) contains 99.9% purity of butene at 285.4 K and200 kPa, which is then recycled back to the reactor (R-02) for further cracking reaction intosmaller hydrocarbon.
Table 5.3: Requirement conditions of the second distillation column (D-03).
Distillation Column2 (D-03) Number of stages 35
Feed stage 8Reflux ratio 0.6
Distillate to feed mole ratio 0.867Condenser type Partial
Condenser Pressure 8.5 barReboiler Pressure 2 bar
5.3.3 Catalytic Cracking Reaction
The fluid catalytic cracking takes place on the heterogeneous catalyst and it is realized in thesorbed phase, where the acid sites, on the catalyst surface, assist in the formation of and determine
the type of reactions undergone by ionic intermediary species, carbonium ions.[16]
Figure 2 belowshows the reaction routes of carbonium ion in n-Paraffin catalytic cracking.[17]
Figure 5.1: The reaction routes of carbonium ion in n-Paraffin catalytic cracking. [17]
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Lets consider the cracking of normal paraffin. In the first step of reaction, the intermediate product, carbonium ion is formed. According to modern theories, acidic sites of the Bronsted(*H+) or the Lewis (*) type, which is strongly deficient in electrons, may stabilize one of the
hydrogens of the paraffin molecule in the form of hydride ion (H-
), with the formation of thecomplementary carbonium ion from the hydrocarbon:[16]
Since C-H bond is covalent, its ionization is, on energy considerations, not favored and can onlytake place on very efficient acidic sites. The carbonium ion, once formed on the catalyst surface,may react in various ways. [16]
The Primary Cracking Reaction is the heterolytic cleavage of the C-C bond, located in position to the positive charge, withformation of an olefin and a new carbonium ion: [16]
The primary carbonium ion form is very unstable and undergoes an internal rearrangement bymigration of a hydrogen atom(hydride transfer) , with formation of a more stablesecondary oreven tertiary carbonium ion: [16]
It may happen alsoisomerization of the carbon chain according to the reactions:[16]
Alternatively, they may extract a hydride ion from a molecule in the feed and produce a paraffinand a new carbonium ion: [16]
By referring to the journal written byWang F. et. al. that had been published in theChemical Engineering and Processing 49 (2010) 51-58, there are about 38 reaction involve in thecracking process.[15] However, assumption is made for the simplification of the FCC process inthis RAPID plant. The reactions involve in the FCC process in this plant are:
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No. Reaction Equations1 Light nathpha xC3H6 + yC2H4 + zC4H8 +
wH2 2 C2H6 C2H4 + H2 3 C2H4 + H2 C2H6 4 C2H2+ CH4 C3H6 5 C2H4 + C2H6 + C3H6 + CH4 6 C3H8 C3H6+ H2 7 C3H6 + H2 C3H8 8 C3H8 C2H4 + CH4 9 C3H8+ C2H4 C2H6 + C3H6 10 C3H4 + H2 C3H6 11 C4H6 + H2 C4H8
5.3.4 Justification of Catalyst Used(1) SAPO-11 Catalyst [used in the Reactor (R-02)]
The silicoaluminophosphates (SAPO) molecular sieve has a network of AlO4, SiO4 andPO4 tetrahedra linked by oxygen atoms. The negative charge in the network is balanced by theinclusion of exchangeable protons or cations such as alkali or alkaline earth metal ions. Theinterstitial spaces or channels which are formed by the crystalline network enable SAPOs to beused as molecular sieves in separation processes and in catalysis.[13]
In accordance to Advanced Chemicals Supplier Material [14], SAPO-11 has a linearformula (SiO 2)x (Al 2O 3)y (P 2O 5)z . The technical parameters have been shown in the table 5 below.
Table 5.4: Technical parameters of SAPO-11 by the ACS Material. [14]
Appearance White PowderSpecific Surface Area (m /g) 180Pore Volume (cm /g) 0.16SiO2 (%) ~ 6Al2O3 (%) ~ 48
P2O5 (%) 0.2
There are few patents writing about the using of SAPO catalyst to increase the propylene production. According toChen. T.J. et. al. (U.S. Pat. No. 6,429,348 B1) , they have come out a patent about the invention of usingsilicoaluminophosphates (SAPO) catalyst under catalyticcracking conditions for converting an olefinic hydrocarbon feedstock to propylene. The catalysthas enhanced stability as used when treated with a rare earth metal or metals in a concentrationeffective to provide a catalyst whichexhibits a higher conversion of a hydrocarbon feedstockto propylene than an equal quantity of an untreated sample of the same catalyst under the same
conditions.[13]
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Since there is large volume of production of olefins, small improvements in operatingefficiency translate into significant profits, catalyst play an important role in more selectiveconversion of hydrocarbons to olefins. Non-zeolite molecular sieves such assilicoaluminophosphates (SAPO) catalyst including those describe inU.S. Pat. No. 4,440,871
also provided excellent catalysts for cracking to selectively produce light hydrocarbons andolefins.
Chen. T.J. et. al. (U.S. Pat. No. 6,429,348 B1) has done the experiment to compare the performance of catalyst in the catalytic cracking reaction between the ZSM-5 and SAPO-11.Results have proven thatSAPO-11 produced significantly more propylene and less ethyleneand butene than ZSM-5 catalyst. SAPO-11 was found to be very selective for propylene withpropylene selectivity of 64% and low production of both ethylene and butene. Theconversion of using SAPO-11 is 89.8. [13]
In addition, the most preferably catalytic cracking conditions are in the temperaturerange of 500 C-650 C (773.15 K-923.15 K). Pressure in the contact zone may be from 0.1atm-30 atm (10.13 kPa-3039.75 kPa), and preferably 1-3 atm (101.33 kPa-303.98 kPa). [13]
(2) MFI (Mordenite framework inverted) Zeolite [used in the Gas Membrane (G-01)]
Zeolite is crystalline microporous aluminosilicate materials with a regular threedimensional pore structure, which arethermal and chemical stabilities . Therefore, it is suitableto be used in this plant, as the high temperature required in the gas membrane separation, which is773.15 K. The MFI zeolite has the pore size 0.55 nm and adsorption properties favorable for theseparation of such gases.[5]
MFI type zeolite membranes have verygood permeation and separation properties. Due to their molecular sieve function, zeolite membranes can principally discriminate thecomponents of gaseous or liquid mixtures dependent on their molecular size. [9] Characterization of zeolite membranes is of great importance and among various techniques, gas permeation is anon destructive characterization techniques that allow the separation capability
and the molecular transport phenomena. Moreover, the study has shown that good separation performances of high quality MFI-zeolite membranes through a standard reliable andreproducible characterization procedure using hydrocarbonaceous mixtures at high temperatures.[12]
Zeolite is widely used in varioushydrocarbon processing operations. [10] Besides, it isalso used at industrial scale for gas separations, for example in the field of gas treatment, refiningand petrochemistry.[12]
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5.3.5 REFERENCES
[1]Light naphtha composition. Retrieve 30 September 2012, fromhttp://www.ripi.ir/index.php?option=content&task=view&id=65 [2]Fahim M.A., Alsahhaf T.A & Elkilani A. (2009). Fundamentals of petroleum refining. 1st ed.
Elsevier Science; UK.[3]Sadeghbeigi R. (2000). Fluid Catalytic Cracking Handbook. Design, operation and
troubleshooting of FCC facilities. 2nd ed. Butterworth-Heinemann; United States of America.[4]Hemler C.L. & Smith L.F. Handbook of Petroleum Refining Processes. Chapter 3.3 UOP Fluid
Catalytic Cracking Process.[5]Dong J.H., Lin Y.S. & Liu W. Multicomponent hydrogen/ hydrocarbon separation by MFI-
Type zeolite membranes.[6]Pan M. & Lin Y.S. Template-free secondary growth synthesis of MFI type zeolite membranes.
Microporous and mesoporous material 43 (2001) 319-327.[7]Eldridge R. B. Olefin/ paraffin separation technology: a review. Ind. Eng. Chem. Res. 1993, 32,
2208-2212. Phillips Petroleum Company, Bartlesville, Oklahoma.[8]Coleman S.T., Sawyer G.A. & Bridges R.S. et. al. Production of 1-butene and propylene from
ethylene. United States patent, Pub. No. US 20120095275A1.[9] Masuda T., Fukumoto N. & Kitamura M. et. al. Modification of pore size of MFI-type zeolite
by catalytic cracking of silane and application to preparation of H2 separating zeolitemembrane. Microporous and mesoporous materials 48 (2001) 239-245.
[10]Kang Li. (2007) Ceramic membranes for separation and reaction. John Wiley & Sons, Ltd:UK.
[11]Keady G.S., Puerto J. & Garbouchian B. Cat cracker gas plant process for increased olefinsrecovery. United States patent, Pub. No. US 20010044565A1.
[12]Chau C., Sicard M. & Terrasse P. et. al. Highly selective MFI-zeolite membranes forhydrocarbon separations.
[13]Chen T. J., Davis S.M & Martens L.R.M et. al. Method for selectively producing propylene by catalytically cracking an olefinic hydrocarbon feedstock.
[14]Sapo-11. Advanced Chemicals Supplier Material. Retrieve 14 November 2012, from
http://www.acsmaterial.com/product.asp?CID=70&ID=78 [15]Wang F., Xu Y.Y & Ren J. et. al. Experimental investigation and modeling of steam crackingof Fischer-Tropsch naphtha for light olefins. Chemical engineering and processing 49 (2010)51-58.
[16]Decroocq D. Catalytic Cracking of Heavy Petroleum Fractions.[17]Ishihara A., Inui K., Hashimoto T. & Nasu H. Preparation of hierarchical and Y zeolite -
containing mesoporous silica-aluminas and their properties for catalytic cracking of n-dodecane. Journal of Catalyst 295 (2012) 81-90.
[18]Molecular Sieves. Retrieve 1 December 2012, fromhttp://chem.chem.rochester.edu/~nvd/molecularsieves.html
http://www.ripi.ir/index.php?option=content&task=view&id=65http://www.ripi.ir/index.php?option=content&task=view&id=65http://www.acsmaterial.com/product.asp?CID=70&ID=78http://www.acsmaterial.com/product.asp?CID=70&ID=78http://www.acsmaterial.com/product.asp?CID=70&ID=78http://www.ripi.ir/index.php?option=content&task=view&id=65 -
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5.4 PLANT UNIT 4: ACRYLONITRILE PRODUCTION PROCESS DESCRIPTION
5.4.1 Introduction
Acrylonitrile (ACN) is one of the leading chemicals with a worldwide production of about
5.5 million tonnes in 2012, with total acrylonitrile demand in 2018 is forecast at 6.516 million
tonnes[4]. In this project the target plant capacity is 120 000 ton/yr, corresponding to a reactor
production of 272.29 kmol/h or 14 448.68 kg/h acrylonitrile pol