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Properties and Chemical Composition of Typical CokerGas OilB. Hou a , Z. Cao a , W. Chen a & J. Han aa School of Petrochemical Engineering, Liaoning University of Petroleum and ChemicalTechnology, Liaoning, P.R. China

Available online: 22 Aug 2007

To cite this article: B. Hou, Z. Cao, W. Chen & J. Han (2007): Properties and Chemical Composition of Typical Coker Gas Oil,Petroleum Science and Technology, 25:8, 1013-1025

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Petroleum Science and Technology, 25:1013–1025, 2007

Copyright © Taylor & Francis Group, LLC

ISSN: 1091-6466 print/1532-2459 online

DOI: 10.1080/10916460600688897

Properties and Chemical Composition of Typical

Coker Gas Oil

B. Hou, Z. Cao, W. Chen, and J. Han

School of Petrochemical Engineering, Liaoning University of Petroleum and

Chemical Technology, Liaoning, P.R. China

Abstract: The coker gas oil from Daqing, Shengli, and Liaohe, which are three

famous oil fields in China, are studied. The properties, chemical composition, and

structural composition of coker gas oil from Daqing, Shengli, and Liaohe saturated

hydrocarbon are analyzed. The results show that nitrogen and sulfur content in Daqing

coker gas oil is the lowest, and saturated hydrocarbon content is the highest, and

Daqing coker gas oil is the most easily processed raw material, and Liaohe coker

gas oil mediates between two raw materials, but Shengli coker gas oil is the most

difficult to process. By comparing with vacuum gas oil and nitrogen, sulfur content

and carbon residue in the coker gas oils is higher and saturated hydrocarbon content

is lower. Shengli coker gas oil is a somewhat inferior raw material. The factor of

effecting on the processing and use of coker gas oil are analyzed, and the processing

ways of coker gas oil are put forward.

Keywords: chemical composition, coker gas oil, coking process, measures, process-

ing, property, structural composition

1. INTRODUCTION

Delayed coking is a very well-rounded process for vacuum residuum, and is

always used as a common method of deep process in recent years. Recently,

with quality of crude oil going from bad to worse, process ability of delayed

coking increased quickly. Currently, the processing ability of delayed coking

is more than 13 Mt/year in China, which occupies 7% of the processing

ability of crude oil. Coke chemical products from coking units contain 8–15%

coker gasoline, 26–36% coker diesel oil, and 20–30% coker gas oil (Fusheng,

1995). In addition, sulfide, nitride, aromatic hydrocarbon, and carbon residue

content in coker gas oil is higher. Coker gas oil also contains a large amount

Address correspondence to Wenyi Chen, Liaoning University of Petroleum and

Chemical Technology, Fushun 113001, P.R. China. E-mail: fycwy001@163.com

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1014 B. Hou et al.

of fine coke. Thus, coker gas oil is a kind of inferior raw material in a

direct processing method. It is usually used for feed in secondary operation

sets such as catalytic cracking in foreign countries. However, in inland, it

is restricted in processing for its poor hydroprocessing ability and shortage

of feed in secondary operation sets. Thus, a direct processing method is

usually adopted while the blending ratio of feed is limited (Scientific and

Technical Information Institute of Petrochemical Parent Company of China,

1992). Therefore, how to make good use of coker gas oil in order to improve

economic profits of refinery processing plants is an important issue. The

chemical composition, structural composition, and properties of coker gas oil

from Daqing, Shengli, and Liaohe, which are three famous oil fields in China,

are studied, which is an all-important practical significance of realism.

The chemical composition, structural composition, and properties of

coker gas oil from Daqing, Shengli, and Liaohe saturated hydrocarbon are

analyzed, studied, and compared in this article, and a reasonable project of

processing coker gas oil is presented in order to provide reference for scien-

tific research and produce units.

2. COMPOSITION AND PROPERTIES OF THREE COKER

GAS OIL

2.1. Properties of Three Coker Gas Oil

The properties of three coker gas oils are given in Table 1. From Table 1 we

can see that density and aniline points of three coker gas oils greatly vary.

Table 1. Property of the coker gas oil

Coker gas oil

Item Daqing Shengli Liaohe

Density (70ı) (g.cm�3) 0.8308 0.8831 0.8575

Aniline point/ı 94.7 76.4 82.2

Viscosity (50ı) (mm2 .s�1) 11.7 12.95 11.67

Molecular weight 330 368 365

Refractive index (70ı) 1.4647 1.4920 1.4972

Distillation range/ı 210–489 213–507 243–534

![C], % 86.75 87.41 86.61

![H], % 12.79 12.45 12.65

![S], % 0.20 0.81 0.26

![N], % 0.23 0.55 0.51

![Ni]/(�g.g�1 ) 0.06 0.23 0.79

![V]/(�g.g�1 ) 0.03 0.06 0.06

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Properties and Composition of Coker Gas Oil 1015

However, viscosity, molecular weight, and index of refraction of coker gas

oils from Daqing, Shengli, and Liaohe are rather approximate. The aniline

point in Daqing coker gas oil is 94.7ı, which is the highest among three

coker gas oils. The aniline point of Shengli coker gas oil is 76.4ı, which is

the lowest among the three coker gas oils, and that of Liaohe coker gas oil is

82.8ı, which mediates between two raw materials. Sulfur content in Daqing,

Shengli, and Liaohe coker gas oil is quite close. Sulfur content in Shengli

coker gas oil is 30% higher than Daqing and Liaohe. The varied range of

viscosity of the three coker gas oils is 11.67–12.95 mm2/s, molecular weight

is 330–368, and the index of refraction is 1.4647–1.4920. Nitrogen content

in Shengli and Liaohe coker gas oils is rather close (Shengli is 0.55% and

Liaohe is 0.51%). But nitrogen content in Daqing is only 50% of that of

Shengli and Liaohe. Carbon residue content in Daqing and Shengli coker gas

oils is rather close and is 90% lower than that of Liaohe. Vanadium content

in three coker gas oils is rather close. The varied range is 0.03–0.06 �g/g.

Discrepancy of nickel content is great. The order of nickel content of the three

coker gas oils is Liaohe > Shengli > Daqing. In addition, the data of the

distillation range of the three coker gas oils show that the heavy constituent

of Daqing coker gas oil is lower. Thus, the processing of Daqing coker gas

oil is easier than that of Shengli and Liaohe. Daqing coker gas oil as catalytic

feed is directly blended into feed. The blending ratio is less 20%) and effects

on product distribution and product quality are little (Cungui, Jingren, and

Zhu, 1993).

2.2. Content of Hydrocarbon of Three Coker Gas Oils

The data of content of hydrocarbon and group fractions of three coker gas

oils are given in Table 2 (Wenyi, Dezhi, Shixing, and Shujuan, 1997) and

Table 3 (Wenyi, 1997). From Table 2 we can see that the content of saturated

hydrocarbon in Daqing coker gas oil is highest, Shengli coker gas oil is the

lowest, and Liaohe coker gas oil mediates between two raw materials. From

Table 3 we can see that the order of content of paraffinic hydrocarbons and

Table 2. Content of five group fractions of coker gas oils

Coker gas oil

Content of group Daqing Shengli Liaohe

Saturated hydrocarbon 68.3 55.1 60.9

Light aromatics 7.9 13.6 5.2

Medium aromatics 4.2 8.8 6.5

Heavy aromatics 12.7 15.0 21.5

Resin 6.9 11.5 5.7

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1016 B. Hou et al.

Table 3. Content of hydrocarbon of coker gas oils (1H-NMR) %

Coker gas oil

Content of hydrocarbon Daqing Shengli Liaohe

Paraffintic hydrocarbon 35.1 20.8 27.5

Total naphthenone 32.3 33.1 33.9

Mononuclear naphthenone 17.7 7.8 10.9

Bicyclonaphthenone 8.0 8.1 8.4

Tricyclonaphthenone 3.3 11.2 6.9

Tetracyclonaphthenone 3.3 4.5 5.1

Pentanuclear naphthenone 0 1.5 2.6

Hexacyclic ring naphthenone 0 0.3 0

Total aromatic 26.7 33.3 30.1

Total mononuclear aromatics 7.9 4.6 3.2

Alkylbenzene 3.7 2.2 0.8

Naphthene base alkylbenzene 2.1 1.5 0.9

Bicyclonaphene base

alkylbenzene

2.1 0.9 1.5

Total bicyclic aromatics 7.4 4.4 3.6

Naphthalene group 1.9 0 0

Acenaphthene group C

diphenylene-oxide

2.2 2.8 1.5

Fluorene group 3.3 1.6 2.1

Total triaromatics 5.6 5.0 5.9

Phenanthrene group 3.4 3.1 3.1

Cycloalkane naphthene

phenanthrene group

2.2 1.9 2.8

Total tetranuclear 4.3 10.7 11.0

Pyrene group 3.1 5.7 5.9

Chrysene group 1.2 5.0 5.1

Total pentanuclear

aromatics

0.4 3.9 2.3

Pyrene group 0.4 3.9 2.3

Dibenzanthracene 0 0 0

Total thiophene 1.0 3.2 2.7

Benzothiophene 0.4 1.7 0.7

Dibenzothiophene 0.4 1.1 0.6

Thiophanthrene 0.2 0.4 0.4

Unappraisal aromatic 1.1 1.5 1.4

Resin 6.9 12.8 8.5

aromatic hydrocarbon in three coker gas oils is Daqing > Liaohe > Shengli.

The content of naphthenone of three coker gas oils is close in proximity.

Three coker gas oils contain no asphalt which is a common characteristic of

coker gas oils of China.

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Properties and Composition of Coker Gas Oil 1017

Table 4. The average structural parameters of coker gas oils

Coker gas oilThe average

structural parameters Daqing Shengli Liaohe

!(CA) 14.79 19.71 16.44

!(CN/, % 14.78 22.76 18.69

!(CP/, % 70.34 58.07 64.87

RA 1.24 1.40 1.17

RN 0.89 1.12 1.23

RT 2.13 2.51 2.28

2.3. The Average Structural Parameters of Coker Gas Oils

By using improved B-L method, the data of the average structured parameters

of coker gas oils are given in Table 4 (Wenyi and Yongmin, 1999).

These data show that the order of the aromatic carbon rate !(CA) of

these coker gas oils is Shengli > Liaohe > Daqing; !.CP/ C !.CN/ are

more than 70%. The total cycle number RT is 2.13–2.51 and aromatic cycle

number RA is 1. By comparison, the aromatic carbon rate and aromatic cycle

number of Shengli coker gas oil are higher than those of Daqing and Liaohe.

This shows that Shengli coker gas oil is a kind of inferior raw material.

3. PROPERTY AND COMPOSITION OF VACUUM GAS OIL

The data of property and composition of vacuum gas oil from Daqing,

Shengli, and Liaohe are given in Table 5. By comparing the data of prop-

erty and composition of the three coker gas oils in Tables 1–4, we can see

by comparing with vacuum gas oil, the property of coker gas oil which is

product of secondary operation, is different. The discrepancy follows:

1. Nitrogen content in coker gas oil is higher. Nitrogen content of Daqing

coker gas oil is about 3.2 times in comparison to its vacuum gas oil. The

nitrogen content of Shengli coker gas oil is about 3.9 times as compared

with that of its vacuum gas oil. Nitrogen content of Liaohe coker gas oil

is about 1.2 times as compared with that of its vacuum gas oil.

2. Saturated hydrocarbon (alkane C naphthenone) content in coker gas oil is

lower. Saturated hydrocarbon content of Daqing coker gas oil is 15.42%

lower than that of its vacuum gas oil. Saturated hydrocarbon content of

Shengli coker gas oil is 21.55 lower than that of its vacuum gas oil.

Saturated hydrocarbon content of Liaohe coker gas oil is 15.4% lower

than that of its vacuum gas oil.

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1018 B. Hou et al.

Table 5. Property and composition of vacuum gas oil

Coker gas oil

Property and composition Daqing Shengli Liaohe

Relative density (20ı) 0.816 0.902 0.919

Formula weight 361 383 370

! [carbon residue], % 0.15 0.27 0.95

![C], % 83.79 86.83 86.71

![H], % 15.67 12.29 12.70

![S], % 0.051 0.73 0.18

![N], % 0.072 0.14 0.41

Distillation range/ı 210–478 225–522 231–511

Content of group, %

Alkane C naphthenone 83.72 72.42 76.30

Mononuclear aromatics 7.50 12.03 7.21

Bicyclic aromatics 3.22 3.47 3.30

Polycyclic aromatic hydrocarbon 4.50 8.30 11.60

Resin 1.06 3.78 3.31

The average structural parameters

!.CA/, % 11.05 14.53 17.91

!.CN/, % 14.78 24.17 30.88

!.CP/, % 73.17 61.30 51.21

RA 0.51 0.58 0.96

RN 0.83 1.53 2.13

RT 1.34 2.11 3.09

3. Aromatic hydrocarbon content in coker gas oil is higher. Aromatic hydro-

carbon content of Daqing coker gas oil is 9.58% higher than that of its

vacuum gas oil. Aromatic hydrocarbon content of Shengli coker gas oil

is 13.87% higher than that of its vacuum gas oil. Aromatic hydrocarbon

content of Liaohe coker gas oil is 11.1% higher than that of its vacuum

gas oil.

4. Rinse content in coker gas oil is higher. Rinse content of Daqing coker

gas oil is 6.51 times as compared to that of its vacuum gas oil. Rinse

content of Shengli coker gas oil is 3.04 times as compared with that of

its vacuum gas oil. Rinse content of Liaohe coker gas oil is 1.78 times

as compared with that of its vacuum gas oil. The aromatic cycle number

is 2.13–2.51, which is comparable to vacuum gas oil. Subsequently, the

carbon residue and dry point of the three coker gas oils are close to those

of vacuum gas oil.

We can see that nitrogen, aromatic hydrocarbon, and resin content in

coker gas oils, which are products of secondary operations, are higher. There-

fore, coker gas oil is a kind of inferior raw material.

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Properties and Composition of Coker Gas Oil 1019

4. RESEARCHING A REASONABLE PROJECT ON THE

PROCESSING AND USE OF THREE COKER GAS OILS

4.1. The Factors of Effecting on the Processing and Use of Coker

Gas Oils

The main effecting factors in the processing and use of coker gas oils are

nitrogen, aromatic hydrocarbon, and resins content.

4.1.1. Nitride

The main effects of nitride are basic nitride (about 1/3 total nitrogen content),

which is absorbed in the acid active center of the catalyst and decreases the

activity of the catalyst in reaction process. The effects of basic nitrogen

on gasoline yield (C5–232ı) and conversion are given in Figures 1 and 2,

respectively.

Research shows (Tao, 1994) when nitrogen content in feed is increased,

conversion and gasoline yield are decreased. The TOPSOE Corporation (Mas-

sachusetts) states that when nitrogen content in feed is increased 100 �g/g,

conversion is decreased 0.3%–0.5%, gasoline volume loss and conversion is

about 1:1, and gasoline bromine value is increased 2–3 units. The Engelhard

Corporation (New Jersey) states that the total nitrogen content is no more

than 2,000 �g/g. When nitrogen content in feed is increased 100 �g/g, con-

version is decreased 0.7–0.9%. UNOCAL Corporation (California) research

states that most catalytic cracking units permit that basic nitrogen content is

Figure 1. Effects of basic nitrogen on gasoline yield.

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1020 B. Hou et al.

Figure 2. Effects of basic nitrogen on conversion.

no more than 1,000 �g/g. In foreign countries, hydrogen cracking units per-

mit that nitrogen content in feed is no more than 3,000 �g/g (induced four set

hydrogen cracking units permit nitrogen content is 670–2,100 �g/g). Thus,

nitrogen content in coker gas oil limits the blending refining ratio in catalytic

cracking and hydrogen cracking. Presently, the blending refining ratio in feeds

of catalytic cracking is 5–25%, the blending refining ratio of feed of hydro-

gen cracking is about 10%. Thus, the main problems on nitride in coker gas

oil are that conversion and light gasoline yield is decreased, coke-forming

content is increased, product quality is decreased, and the environment is

polluted.

4.1.2. Aromatic Hydrocarbon Content

Effects of aromatic hydrocarbon are polycyclic aromatic hydrocarbon in feed.

In general, when polycyclic aromatic hydrocarbon is increased, single pass

conversion and gasoline yield in catalytic cracking is decreased, and coke

yield is increased. Effects of aromatic hydrocarbon content of stock on the

distribution of the product are given in Table 6 (Tao, 1994).

4.1.3. Carbon Residue and Resins

Effects of carbon residue and resins are coke-forming content. The effects of

carbon residue and resins on the distribution of products are shown in Table 7

(Yongqing, 1995).

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Properties and Composition of Coker Gas Oil 1021

Table 6. Effects of aromatic hydrocarbon of catalytic cracking stock

Catalytic cracking stock

Composition of stock and

distribution of product

Polycyclic

aromatic

hydrocarbon-rich

stock

Mononuclear

aromatics

hydrocarbon-rich

stock

! (composition of stock), %

Paraffin 11.5 3.0

Naphthenone 15.5 14.0

Mononuclear aromatics hydrocarbon 0.4 42.4

>Bicyclic aromatic 73.0 40.6

Total aromatics 73.4 83.0

! (product distribution) (55% conversion), %

<C3 5.9 5.6

C4ı 6.7 8.0

C5-221ı 21.2 34.3

Coke 28.2 13.6

ıvolume fraction, %

Table 7. Effects of carbon residue and resins on distribution of product

StockContent of group fraction

and distribution of product VGO DAO DAO DAO

! (carbon residue), % 0.14 3.2 3.87 6.26

! (content of group fraction), % 69.8 70 28.7

Saturated hydrocarbon

Arene 23.6 39.4 40.6

Resins 6.6 13.6 30.7

! (distribution of product), %

Dry gasCliquefied gas 17.62 14.75 15.46 13.45

Gasoline 49.94 40.88 42.50 39.44

Light diesel oil 20.10 21.76 20.99 21.18

Masout 9.02 16.37 12.80 16.17

Coke 3.30 6.24 8.25 9.70

! (conversion), % 70.88 61.87 66.21 62.65

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1022 B. Hou et al.

4.2. Path of Processing and Using and Measures Adopted for

Three Coker Gas Oils

From Table 1, we can see that the nitrogen content of Daqing, Shengli, and

Liaohe coker gas oils is 2,300 �g/g, 5,500 �g/g, and 5,071 �g/g. These

data exceed the maximum limit permission (catalytic cracking <2,000 �g/g,

hydrogen cracking <670–2,100 �g/g in China) (Tao, 1994). The effects of

heavy aromatic hydrocarbon and resin content as compared, to masout and

residuum is not significant. Thus, coker gas oil needs dentrogenation processing

whether coker gas oil is used for feed in catalytic cracking or for feed in hy-

drocracking. The measures adopted for coker gas oil denitrogen are as follows:

1. Hydroprocessing: In foreign countries, coker gas oil is usually hydropro-

cessed for catalytic cracking feed. For instance, in the U.S. more than 50%

of feed for catalytic cracking is being hydroprocessed, and about 10% in

West Europe is done in the same way. It has been proven by practice that

coker gas oil after hydroprocessing, its contents of sulfur and nitrogen

are obviously decreased, PAH and residue carbon decreased, and the part

of heavy metal removed, which is better feed for cracking. In China, the

change of the main properties of the product is given in Table 8 when

coker gas oil after hydroprocessing by Shengli refinery processing plant

of Qilu Petrochemical Corporation (Shandong, China). Nitrogen content is

decreased from 0.51% to 0.18%, and the denitrification ratio is 64.7%. The

nitrogen content is reaching the limit which is no more than 2,000 �g/g. In

the meantime, carbon residue is decreased from 0.38% to 0.039%, resins

are decreased from 13.8% to 3.2%; these norms lead to straight-run wax

oil. But some norms such as density and sulfur content are better than

Table 8. Compared with vacuum gas oil and hydrogenation of coker gas oil

Property

Coker

gas oil

Refining

coker gas oil

Straight-run

wax oil

Relative density (20ı) 0.927 0.889 0.915

![S], % 0.75 0.01 0.71

![N], % 0.51 0.18 0.14

![Ni]/(�g.g�1 ) 0.20 0.11 0.50

![V]/(�g.g�1 ) 0.03 0.01 0.01

![carbon residue], % 0.38 0.04 0.27

![C], % 86.77 86.97

![H], % 11.96 12.84

! (content of group fraction), %

Saturated hydrocarbon 54.7 64.1 71.22

Arene 31.5 32.7 24.94

Resins 13.8 3.2 3.84

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Properties and Composition of Coker Gas Oil 1023

straight-run wax oil. The hydroprocessing coker gas oil is a somewhat

better catalytic cracking raw material. Fushun Research Institute of Petro-

chemicals (Liaoning, China) developed and adopted a FCT catalyst, under

the condition of hydrogen pressure at 6.4 MPa, 380ı and space velocity

1.0 h�1, treat coker gas oil of Nanjing and Changling pipe transport, the

nitrogen content of coker gas oil is decreased from 0.42 to 0.1%. The

rate of denitrogen access is 80%, the rate of deresination is 72–86%, and

the rate of carbon residue removal is 70–80% (Yan, Dengling, Guangwei,

and Minghai, 1995). Coker gas oil is a kind of high-grade raw material.

Liaohe coker gas oil is treated at the Jinxi (Liaoning, China) refinery plant,

under the condition of hydrogen pressure at 6.0–7.0 MPa, 370ı–400ı and

space velocity 1.0–1.5 h�1 treat, the nitrogen content is decreased from

0.5527% to 0.1824–0.3781%, the rate of denitrogen is 31.6–67.0%, the

rate of basic nitrogen removal is 20.5–71.8%, and the rate of sulfur re-

moval is 80.6–88.9%.

2. Solvent extraction: In the 1950s, it had been widely used to refine cracking

cycle oil and coker gas oil with a solvent extraction unit abroad. For ex-

ample, Nanjing Refinery of Jinling Petro Chemical Corporation (Jiangsu,

China), extractive refined coker gas oil with furfurol. Under the yield of re-

fining raffinate oil is 80%, with contents of nitrogen decreasing 1,000 �g/g,

which is better feed for catalytic cracking. Using a lubricating oil extract

phase to extract coker gas oil can greatly decrease the contents of basic

nitrogen and resins, and at the same time increase the yield of raffinate

oil (Yuzhang and Luo, 1996).

3. Using an effective anti-nitrogen catalyst: Basic nitrogen can greatly be

adsorbed at the acidic center of a crack catalyst, which decreases the cat-

alytic activity of catalyst. Therefore, the design and use of an anti-nitrogen-

cracking catalyst is the inexpensive and simple method for solving high

nitrogen contents of coker gas oil. Several aspects of an anti-nitrogen

catalyst should be considered (Zhemin, 1995): (1) the zeolite content of

a cracking catalyst is improved and the bit concentration is increased;

(2) The acid supporter is adopted; and (3) the cleaning agent of nitrogen

is introduced into cracking catalyst. The basic nitrogen of raw material is

absorbed in cleaning agents of nitrogen. Thus, the acid bit of zeolite of

a cracking catalyst is protected. Research show that under the condition

of the same microreactor activity, a molecular sieve catalyst with a high

density of acidic center is better for improving the activity of the catalyst;

existence of rare earth in a molecular sieve is beneficial for anti-nitrogen.

Using an acidic additive as a collecting agent to relieve the poison of

nitrogen is an important method. Presently, we use anti-nitrogen catalysts

such as RHZ-200, LC-7, CCC-1, and RHZ-300 on a commercial scale,

which creates good results. Coker/gas selectivity is therefore improved.

Thus, an anti-nitrogen catalyst is suitable for faulty raw material, espe-

cially when the nitrogen content of raw material is high, and the blending

refining ratio is improved.

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1024 B. Hou et al.

4. Denitrogen by complexation reaction: Using transition mental chloride

such as titanium tetrachloride, copper dichloride removes nitride of coker

gas oil (Xigong and Hong, 1996).

5. Use solid adsorbed to remove nitride: Fushun Petroleum Institute devel-

oped a method that uses A, B solid absorbers after being modified, un-

der mild conditions (temperature of 55ı–95ı, space velocity of 0.5 h�1–

3.0 h�1), the rate of removing basic nitrogen from Daqing coker gas oil

is 83.5%, and the absorber can be regenerated in solvent.

Moreover, coker gas oil is classified as light coker gas oil and heavy

coker gas oil. It is suggested that 15% heavy constituent is used for coking

oil. 85% light coker gas oil is catalyzed. It has been proven by the Shijia

Zhuang Refinery Plant (Hebei, China) that 20% light coker gas oil is blending

in catalytic unit; process of unit and total liquid yield is not greatly affected.

To summarize, coker gas oil is used for feed of catalytic cracking. Un-

der certain conditions, coker gas oil is added to vacuum gas oil, then is

hydroprocessed, or coker gas oil is hydroprocessed, and is then added to

catalytic raw material, which meets the limit of nitrogen content no more

than 2,000 �g/g of feed. The developing engineering process is simple and

convenient, and operation condition is moderate. Using a cheap absorber to

remove the basic nitrogen of coker gas oil is a good method for using coker

gas oil. Using organic acid, complexant to remove nitride is a simple and

convenient method. The development and use of an anti-nitrogen catalyst is

a reasonable processing method.

5. CONCLUSION

The order of content of paraffinic hydrocarbons and aromatic hydrocarbons

in three coker gas oils is Daqing > Liaohe > Shengli. The order of content of

resin and aromatic hydrocarbons is similar to that of paraffinic hydrocarbon.

The content of naphthenone of three coker gas oils is close. Three coker gas

oils contain no asphalt. The order of the aromatic carbon rate !(CA) of these

coker gas oils is Shengli > Liaohe > Daqing; !.CP/ C !.CN/ are more than

70%. The aromatic cycle number RA is 1 and the total cycle number RT is

2.13–2.51.

The viscosity, molecular weight, refractive index, and content of heavy

metal in three coker gas oils are rather similar. However, the contents of sul-

fur, nitrogen, and aniline point are greatly different. The contents of nitrogen,

sulfur, carbon residue, and heavy metal in Daqing coker gas oil are the lowest,

and the saturated hydrocarbon content is the highest. Thus, the processing

of Daqing coker gas oil is easier than that of Shengli and Liaohe. Daqing

coker gas oil as catalytic feed is directly blended into feed (blending ratio is

less than 25%). However, the contents of nitrogen, sulfur, aromatic hydrocar-

bons, and aromatic cycle numbers in Shemgli coker gas oil are the highest.

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Properties and Composition of Coker Gas Oil 1025

Thus, the processing of Shengli coker gas oil is harder than that of Daqing

and Liaohe.

The primary factors effecting the processing and use of coker gas oil

are that the content of nitrogen is high and saturated hydrocarbon content

is low. The content of aromatic hydrocarbon (alkane C naphthenone) is low

and the contents of aromatic hydrocarbon and resin are high. The measures

adopted include: hydroprocessing, solvent extraction, using effective anti-

nitrogen catalyst and denitrogen by complexation reaction.

REFERENCES

Chen, X., and Zhu, H. (1996). Petrochem. Tech. 3:10–15.

Chen, W. (1997). Petrol. Prec. and Petrochem. 28:52–57.

Chen, W., Zhao, D., Chen, S., Liu, S. (1997). J. Fu Shun Petrol. Inst. 17:

22–24.

Chen, W., and Liu, Y. (1999). Petrochem. Tech. 28:185–188.

Hou, F. (1995). Manual for Engineer of Petroleum Refining. Beijing: Petro-

leum Industry Press.

Huo, Y. (1995). Catal. Cracking 2:27–41.

Hou, Z. (1995). Changling Refining Sci. Tech. 2:19–23.

Mei, C. Liu, J., and Liu, P.-Z. (1993). Petrol. Proc. 24:9–13.

Scientific and Technical Information Institute of Petrochemical Parent Com-

pany of China. (1992). Developments of Petrochemicals 15:1–27.

Wang, Y., and Ding, L. (1996). Petrol. Proc. Petrochem. 27:18–23.

Zhang, T. (1994). Hydrogenation Tech. 4:45–65.

Zhao, Y., Wei, D., Cao, G., and Tong, M. (1995). J. Fushun Res. Inst.

Petrochem. 8:31–36.

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