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A
SEMINAR REPORT
ON
Sources and characteristics ofPollutants in
Petroleum and petrochemical industries
Submitted By
j.raju 07H61A0818
Departmentof Chemical Engineering
COLLEGE OF ENGINEERINGHYDERABAD
2007-2011
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CERTIFICATE
This is certify that the report entitled Sources and characteristics of
Pollutants in Petroleum and petrochemical industries is beingsubmitted by J.RAJU ( 07H61A0818) .In partial fulfillment for the
award of the B.Tech (chemical) from C.V.S.R COLLEGE OF
ENGINEERING affiliated to JNTU, HYDERABAD is a record of
bonified work carried out under our guidance and supervision duringthe academic year 2010-2011.
(Dr. M. Bhagvanth Rao)
Professor& Director
(HOD Chemical Engineering Dept)
CONTENTS
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ABSTRACT
DEFINITION
CLASSIFICATION
EXPLANATION
SOURCES AND CHARACTERISTICS
EFFECTS ON ENVIRONMENT
CONTROL TECHNIQUES
CONCLISION
REFERENCES
ABSTRACT:-
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The source and characteristic of pollutants in petrolium and
petro chemical indusssssssss
Classification of pollutants:-
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Pollutants
Primary pollutants secondary pollutants
1. Primary pollutants:
These pollutants emitted directly from identifiable sources.
Primary emissions include particulate matter, sulphur compounds, organic
compounds, nitrogen compounds, carbon compounds, halogen compounds, radio
active compounds etc.
2. Secondary pollutants:
These pollutants produce in the air by interaction among to or from primary
pollutants or by reaction with normal atmosphere constituents.
These pollutants are formed by interaction between various primary pollutants
and/or normal constituents of air.
Examples of these pollutants are formation of sulphuric acid mist, smoke etc.
POLLUTANTS FROM PETROLEUM AND PETROCHEMICAL
INDUSTRIES:
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1. Air pollutants:
Major air pollutants that may be emitted from refining operations are
1. Sulfur compounds
2. Hydrocarbons
3. Nitrogen oxides
4. Particulates including smoke
5. Carbon monoxide
Other emissions
1. Aldehydes
2. Ammonia
3. Odors
Petroleum refineries differ in the type of processing schemes employed, type of
units used in a given processing scheme, the type of crude or crude processed,
varieties of end products, location, source of power, utilities requirements and
operating and housekeeping practices.
All these factors have a bearing in varying degrees on the quantities of emissions
from each refinery. Consequently it is desirable to undertake individual refinery
measurements or calculations to estimate factors for this purpose.
A survey of gaseous emissions from petroleum refineries is given in table below
POLLUTANTS EMISSION
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S.NO TON/DYY
1
Carbon monoxide 13
2
Hydrocarbons 7
3
Aldehydes, organic acids 1
4
Sulphur dioxide 5
5
Nitrogen oxides 4
1. Sulphur compound:
Sulphur dioxide constitutes the maximum proportion of sulphur compound emitted
from refineries.
The main sources of sulphur dioxide are fuel combustion which are emitted from
combustion operations, such as fires heaters, boilers and catalytic cracking
regenerators and from sulphur dioxide extraction plants.
Any organic sulphur contained in a fuel is oxidized to sulphur dioxide or sulphur
trioxide during combustion. Normally about 97% of the fuel sulphur to sulphur
trioxide during combustion. Eventually however considerably more of the sulphur
dioxide is oxidized to sulphur trioxide in the ambient air, ultimately forming sulphate
particulates.
The amount of sulphur dioxide emission depends upon the type and amount of fuel
burnt and its sulphur content.
Emissions of oxides of sulphur are expressed in terms of sulphur dioxide knowing the
quantity of fuel used based either on flow meter reaching or actual tank gauges, and
the sulphur content of the fuel from actual laboratory analysis, the emissions of
sulphur dioxide may be easily calculated. Actual monitoring of stack gases on such
cases may not n[be necessary.
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Refinery flares incinerators and decoking operations are other minor sources.
Other sulphur components emitted from refineries hydrogen sulphide, sulphur trioxide
and mercaptants from treatment processes. However, these emissions are in from
evaporation of leaks and vent losses from storage facilities.
2. Hydrocarbons:
The emissions of hydrocarbons result mainly from evaporation of light oil during
storage and handling of crude and petroleum products and from leaks.
Sources of hydrocarbon emission include loading facilities, sampling, sampling,
storage tanks, and waste water separators. The extent of these emissions depends upon
design maintenance and operating practice.
These emissions cannot be directly measured except in the case of unburnt
hydrocarbons released during combustion operations. These may be measured by
direct stack monitoring.
The major sources of hydrocarbon emission however, are evaporation losses from
storage tanks and from oil separators. These losses can only be estimated by
empherical formulae based on extensive testing and experience.
3. Oxides of nitrogen:
Combustion of fuel in fired heaters and boilers and internal combustion engines used
to drive compressors and electric generators are the main sources of nitrogen oxides
are also released from catalytic cracking regenerators and from co boilers.
Combustion of fossil fuels produces nitrogen oxides partly from the combination of
atmospheric nitrogen with excess oxygen in the furnace atmosphere, and partly from
combination of nitrogen oxides is mainly dependent on the flame temperature. The
residence time at this temperature and the excess air present in the flame.
4. Particulates:
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The major sources of emission of particulates in the petroleum refineries are catalytic
cracking regenerators.
The minor sources include internal combustion engines used to drive compressors and
electrical generators and incinerators.
Incomplete combustion in furnaces and boilers also generates carbon monoxide
emissions.
The only significant source of carbon monoxide is the catalytic cracking regenerator.
When co boiler is not employed. No emissions of carbon monoxide are released.
When co boilers does not exist the emissions can be accurately calculated based on
stock gas analysis for carbon monoxide content and the quantity of air used for
regeneration, which is measured and controlled.
5. Carbon monoxide:
The only significant source of carbon monoxide in refineries is the catalytic cracking
regenerators. This, however is eliminated in units a CO boiler.
The minor sources include internal combustion engines used to drive compressors and
electric generators and incinerators. Incomplete combustion in furnaces and boiler and
also in generates CO emissions.
The only significant source of CO is the catalytic cracking regenerator when CO
boiler is not employed. No emissions of CO or released when CO boilers are used.
Where CO boilers do not exist the emissions can be accurately calculated based on
stock gas analysis for CO content and the quantity of air used for regeneration which
is measured and controlled.
11. Effects of Air pollutants on the environment:
1. Reduction in visibility
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2. Damage to the material
3. Damage to vegetarian
4. Physiological effects on man and animals
5. Physiological effects
3. AIR POLLUTANTS CONTROL TECHNIQUES AND OPTIONS:
The control of air pollution is an expensive and complex problem because the
character and quantity of refinery atmospheric emissions vary greatly from
refinery to refinery.
Refinery air pollution control techniques exist which should permit refineries to
operate in any community without constituting a serious air pollution problem. A
realistic control strategy, size of the installation, cost benefits, commercial and
possibility of creating other disposal problems.
The majority of refinery emissions occur during combustion in providing power
and heat for processing operators. These include combustion of fuel in boilers for
steam generation combustion of fuel in fired heaters and combustion of carbon
during regeneration of cracking catalysts.
1. CONTROL OF EMISSIONS FROM REFINERY PROCESS GASES:
Minimize sox emission either through desulfurization of fuels to the extent feasible
or by directing the use of high sulfur fuels to units equipped with so x emission
controls.
Nearly all refineries process generates gases which generally contain hydrogen
sulphide or other low molecular weight sulphur compounds. These gases are
normally used as fuel in fired heaters and reboilers.
The most common procedure for removal of hydrogen sulphide and light
mercaptants involves scrubbing the gases with an solution. Solvent such as
aqueous amine solution. The amine solution extracts the hydrogen sulphide and id
then regenerated by stripping hydrogen sulphide with heat and/or steam. The
regenerated solution is reused for further absorption. The hydrogen sulphide
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recovered from this process can be converted to either sulphuric acid or elemental
sulphur.
Prevention and control of pollution in petroleum:
Petroleum refineries are complex plants, and the combination and
sequence of processes is usually very specific to the characteristics of
the raw materials (crude oil) and the products. Specific pollution
prevention or source reduction measures in these areas should be
designed into the plant and targeted by management of operating
plants.
Reduction of air emissions:
1. Minimize losses from storage tank and product transfer areas by
methods such as vapor recovery systems and double seals.
2. Minimize SOx emissions either through desulfurization of fuels, to
the extent feasible, or by directing the use of high-sulfur fuels to
units equipped with SOx emissions controls.
3. Recover sulfur from tail gases in high-efficiency sulfur units.
4. Recover non silica-based (i.e., metallic) catalysts and reduce
particulate emissions.
5. Use low-NOx burners to reduce nitrogen oxide emissions.
6. Avoid and limit fugitive emissions by proper process design and
maintenance.
7. Keep fuel usage to a minimum.
Elimination or Reduction of pollutants:
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1. Consider reformate and other octane boosters instead of tetraethyl
lead and other organic lead compounds for octane boosting.
2. Use non-chrome-based inhibitors in cooling water, where
inhibitors are needed.
2. WATER POLLUTANTS:
Water pollution due to discharge of industrial wastes has already become a serious
problem in certain areas of the country. The current practices adopted for the
disposal of industrial wastes in the country include discharge into public sewers,
rivers or sea through creeks and estuaries and on land.
Water is used in petroleum refineries for a variety of purposes. Since water does
not enter into the final product, it can be expected that 80-90% of the water
supplied to the refinery comes out as waste water. The characteristics of waste
water from petroleum refineries in India and their pollutant. It indicates that large
volumes of waste water are being discharged containing a variety of objectionable
and toxic organic and inorganic substances. If these waste water are not treated to
the desired degree, the pollutants reach the water course and bring out a number of
chances in the quality of the receiving water, which ultimately render the water
unsafe for aquatic life and for domestic and industrial use.
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]CHARACTERISTICS OF WASTE WATER AND POLLUTANTS/TOIX
CONSTITUENTS:
SI NO Effluents characteristics VALUE Pollution/toxic constituents
1 Flow, l/kg oil 1.5 1. free oil(2000-3000 mg/l)
2 pH 6.8-7.2 2. emulsified oil(80-120
mg/oil)
3 Suspended solids, mg/l 200-400 3.H2S & RSH (10-220)
4 BOD, mg/l 100-300 4. Phenols (12-30 mg/l)
5 COD , mg/l ------ 5. Ammonia andchromium if cooling
water is mixed with
process water.
6 BOD/COD ------
7 BOD load, gm/unit product 0.3
TYPES OF WATER POLLUTION:
1. PHYSICAL POLLUTION
2. CHEMICAL POLLUTION
3. PHYSIOLOGICAL POLLUTION
4. BIOLOGICAL POLLUTION
1. PHYSICAL POLLUTION:
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This is due to temperature, turbidity, suspended matter. Color, foam and
froth and radioactivity
Waters with higher temperature are usually encountered from thermal power
stations, cooling systems, etc. A mere rise of temperature by a few degreescentigrade decreases the solubility of oxygen in water and this can affect the
receiving stream in two ways. It will increase the biological activity vis--vis
decrease the dissolved oxygen (DO) content and secondly, it will make the fish
migrate to other areas because of low DO and higher temperature. Because of
this, tolerance limits for temperature are prescribed for waste water for
discharge into inland surfaces waters.
Color in general considered as aesthetic pollutant. Color can be associated with
natural as well as artificial substances. Color can reduce photosynthetic activity.
2. CHEMICAL POLLUTION:
This can be due to inorganic and organic chemicals. Inorganic chemicals
include acids, alkalies, heavy metals, soluble salts or inert insoluble substances.
Inorganic acceleration corrosion of metals destroys cotton textiles, kill aquatic
organisms and burn or irritate the skin of animals and humans. When pH of the
water is below 5, the damage is greater. Both acids and alkalies can be toxic to
all aquatic organisms and thus inhibit self purification in streams.
Waste containing free chlorine, chloramines, ammonia, soluble sulphides and
salts of metals such as arsenic, cadmium, chromium, copper, lead, mercury,
nickel, selenium etc. are also highly toxic. These are toxic to fish and also to
humans.
Some of the metals accumulate in ecosystems and reach man and animals.
Soluble salts commonly found in streams include chlorides, sulphates and
bicarbonates of sodium, potassium, calcium, magnesium, iron and manganese.
Sources of oil pollution are from waste waters discharged from ships and oil
tankers, oil refineries, industrial plants handling oil and grease, lubrication of
machinery, metal reduction works, petroleum production spills and wastes.
3. PHYSIOLOGICAL POLLUTION:
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Taste and odour constitute physiological pollution. Several industrial wastes
contain chemicals which impart characteristic and unpleasant taste to water.
Salts of iron and manganese, chlorine, hydrogen sulphide, phenols, can be cited
as examples. Water pollution by industrial wastes containing taste-producing
substances may damage the value of fisheries.
4. BIOLOGICAL POLLUTION:
It is a result of discharge of waste water containing pathogenic forms of
bacteria, fungi, algae, viruses, protozoa and halminthic parasites.
This type of pollution is often a secondary result due to contamination by
sewage or industrial wastes. The diseases related to biological pollution are
cholera, typhoid, dysentery, gastroenteritis, and polio-myelitis.
CONTROL OF WATER POLLUTION:
The uses of water can be categorized as drinking, cooling, boiler feed, direct
processing, sanitary and fire protection. The effluent waste originated can be
classified under:
a. Water free from oil
b. Sanitary sewage
c. Process effluents.
The water free from oil includes storm water from oil free catchment areas,
water treatment plant effluent, boiler blown down etc. The process effluents are
basically oily waters originating from different sources, such as drainage from
pump houses, blow down from cooling systems, desalter water, overhead
condensate water from process units, spent caustic etc.
For effective treatment of the effluent water, the streams are segregated throughseparate drainage systems and treated accordingly. The effluent treatment is
usually divided into three categories, i.e., primary, secondary and tertiary
1. PRIMARY TREATMENT METHODS:
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This treatment consists of oil removal in two stages by physical methods.
Various physical methods are available and these can be classified as baffling,
floatation, skimming, stripping, stripping and extraction.
The first stage of oil removal is done in small pond or basin where majorportion of oil is removed by using baffling, floatation and skimming methods.
The second stage of oil removal is mainly API(American petrol institute)
separators or other gravity separators, where the remaining oil is removed as a
rule should not be omitted as it lessens the oil load on API or gravity separators
and helps in the efficient removal of oil.
2. SECONDARY TREATMENT METHODS:
These methods can be classified as follows:
a. Chemical method
b. Biological method
The main purpose of chemical method is to remove emulsified oil with addition
of flocculating agents and also to remove suspended solids and toxic substances
and thereby condition of effluents for further treatment by biological method.
Biological treatment aims at the removal of all oxidizable and organic matterfrom the waste water. This method of treating waste water employs the use of:
1. Activated sludge process. Conventional and modified
2. Trickling filters
3. Oxidation ponds
4. Aerated lagoons
The activated sludge process is an aerobic biological treatment process. The
conventional process consists of an aeration tank followed by a sedimentation
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tank. In this process high concentrations of newly grown and recycled microbial
biomass are suspended uniformly throughout holding tank to which raw
wastewaters are added.
The tricking filter is a packed media covered with biological slime throughwhich water is percolated.
The treatment of waste water is oxidation ponds provide biological oxidation
and sedimentation similar to that occurring in lakes. Its maintain attraction is
the low cost of construction and operation, but it requires more space and
considerably long detention periods.
The aerated lagoon is smaller, deeper oxidation pond equipped with mechanical
aerators or diffused air units. The addition of oxygen enables the aerated lagoon
to have a higher concentration of microbes than the oxidation pond. The
retention time in aerated lagoons is usually shorter, between 3 and10 day.
3. TERTIARY TREATMENT METHODS:
This treatment has been limited to activated carbon filteration process and
ozonation which are effective in removal of the taste and odour and organics
from biologically treated waste waters. The treated water which satisfy the
relevant tolerance limits are finally disposed by controlled dilution into the
neighbouring stream, river or sea.
SUSPENDED SOLIDS:
Suspended solids causing turbidity tend to reduce light penetration. This may or
may not be beneficial depending upon circumstances and water. For instance
turbidity caused by suspended silt and clay retards algal growth and when this
water is used for drinking.
PH :
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The hydrogen ion concentration of a raw-water source for domestic water is
important as it affects taste, corrosivity, efficiency of chlorination, treatment
processes such as coagulation and industrial applications.
TEMPERATURE:
The increase of stream temperature due to mixing of waste waters causes
undesirable stream conditions such as decreased oxygen capacity, increased
oxygen demand, anaerobic zones and purification of sludge deposits. The
toxicity of many substances is intensified as the temperature rises.
BIOCHEMICAL OXYGEN DEMAND:
In itself, BOD is not a pollutant and exercises no direct harm. However, BOD
does exert an indirect effect by depressing the dissolved oxygen content to
levels that are inimical to fish life and other beneficial uses. BOD effect can be
overcome by reaeration, dilution and/ or photosynthetic effect.
OIL AND GREASE:
Oil in inland surface waters may interfere with gas exchange, coat bodies of
birds and fish and exert a direct toxic action on some organisms as a result of
water soluble components. Oil in water bodies used as a source of domestic
water supply has the following deleterious effects.
a. Hazard to the health of consumers.
b. Production of unpleasant tastes and odours
c. Presence of turbidity, films involving aesthetic problems.
d. Increased difficulty of water treatment.
PHENOLIC COMPOUNDS:
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In water for domestic use harmful concentrations of phenol are much higher
than taste considerations would allow. The concentration of Phenolic
compounds is limited to 0.001 mg/l in drinking water because of tastes resulting
from the action of chlorine on such waters.
CHEMICAL OXYGEN DEMAND (COD):
The determination of COD provides a measure of the oxygen equivalent of that
portion of the organic matter in a simple that is susceptible to oxidation by
strong chemical oxidant. It is important, rapidly measured parameters for
stream and industrial waste studies and for the control of treatment plants with
certain wastes containing toxic substances. The test may be the only method for
determining the organic load. Where wastes contain only readily available
organic bacterial food and no toxic matter, the results can be used toapproximate the ultimate carbonaceous BOD values.
This method however fails in the absence of a catalyst to include some organic
compounds, such as acetic acid which are biologically available to the stream
organism, while including some biological compounds, such as cellulose, which
are not a part of the immediate biochemical load.
Total dissolved solids (TDS). TDS in irrigation water has direct physical effect
in prevention of water uptake by plants (osmotic effect); hence the need torestrict the TDS in irrigation water. Moreover indirect through changes in soil
structure, permeability and aeration also occurs.
BORON:
Although traces of boron are essential for growth of all plants, more than 0.5
mg/l will be injurious to certain plants, like citrus fruits, plums, apples etc.
crops such as potatoes, tomatoes, wheat etc. can tolerate boron up to 2.0 mg/l.
111. SLUDGE TREATMENT AND DISPOSAL:
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Sludge is the suspension of solids in process waters and aqueous wastes.
Sludges produced includes:
1. Crude tank bottoms
2. Slop oil emulsion sludge
3. Cooling tower sludge
4. Lube oil filter cake
5. Heat exchanger bundle cleaning sludge
Sludge is to be prepared and treated for environmentally sound disposal. The
oil content is high. This oil needs to be separated and recirculated. Various
hazardous constituents are needed to be removed ex. Polychlorinatedbiphenyls (PCB).
SLUDGE CHARACTERISTICS:
Sludge must be characterized for pathogenicity, toxicity and various rheological
properties. Sludges need to be tested for pathogenicity. The pathogens organisms
of most concern are some bacteria, viruses, protozoans and parasites, such as
Taenia saginata, potato cyst nematodes and Ascaris. Besides pathogenicity, sludes
need to be tested for toxicity. A range of testes are available for specifictoxicological effects.
SLUDGE CONDITIONING:
Sludge conditioning may be used to increase solids concentration, improve
recovery or reduce thickening time. This can be achieved by chemical addition or
thermal treatment.
CHEMICAL CONDITIONING:
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It involves the use of either inorganic or organic chemicals. The most commonly
used inorganic chemicals for conditioning sludges include lime, ferrous and ferric
sulphates, ferric chloride and alum. Organic polyelectrolytes have been used in
sludge conditioning. These fall into three classes: non organic, anionic and
cationic. The chosen polyelectrolyte should have a charge opposite to that on thesludge particles.
THERMAL CONDITIONING:
The primary function of thermal sludge conditioning is to improve dewaterability.
The advantages of this process include reduced solids quantity, low or very low
specific filtration resistance, sterilization and enhanced activated sludge digestion.
The disadvantages include complex equipment arrangements, including high
pressure and temperature vessels, a serious potential for corrosion, relatively highenergy requirements, potentially severe odour problems, and the production of a
sidestream waste.
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CONCLUSION:
REFERENCES:
Alberini, Anna and Alan Krupnick (2000). Cost-of-Illness and WTP Estimates of the
Benefits of Improved Air Quality: Evidence from Taiwan,Land Economics 76(1).
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Asch, P. and Joseph, J. S. (1978). Some Evidence on the Distribution of Air Quality,
Land Economics, 54, 279-297.
Brainard, J. S., Jones, A.P., Bateman, I. J. and Andrew A. Lovett (2004). Modelling
Environmental Equity: Exposure to Environmental Urban Noise Pollution in
Birmingham, UK, CSERGE, Working Paper EDM 03-04, University of EastAnglia, Norwich (http://www.uea.ac.uk/env/cserge/ pub/wp/
edm/edm_2003_04.pdf)
Brajer, Victor, and Jane V. Hall, (1992). Recent Evidence on the Distribution of Air
Pollution Effects, Contemporary Economic Policy, 10(2): 63-71
Brooks, N. and Rajiv Sethi (1997). The Distribution of Pollution: Community
Characteristics and Exposure to Air Toxics,Journal of Environmental Economicsand Management, 32: 233-250.
Central Pollution Control Board (2001). Parivesh: Newsletter, Ministry of
Environment and Forests, Delhi.
_____(2002). Toxic Air Pollutants,Parivesh: Newsletter, Ministry of Environmentand Forests, Delhi.
Cropper, M.L., Simon, N.B., Alberini, A., Arora, S., Sharma, P.K. (1997). The
Health Benefits of Air Pollution Control in Delhi, American Journal of
Agricultural Economics , 79: 1625-1629.
CSE (1997) Death is in the Air, Down to Earth, Center for Science and
Environment.
Dave, J. M. (2001). Air Quality Management - Dr. Nilay Chaudhury MemorialLecture, Central Pollution Control Board, Delhi.
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