R&D on Catalyst for Cracking of Heavy Oil

7/29/2019 R&D on Catalyst for Cracking of Heavy Oil

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2000.M2.1.3

R&D on Catalyst for Catalytic Cracking of Heavy Oil With High

Metal and High Residual Carbon Content

(High residual carbon catalytic cracking group)

Sodegaura No. 404 laboratoryToshio Ito, Motoo Tanaka, Tomoyuki Sumiyoshi, Yoshifumi Hiramatsu

1. Contents of Empirical Research

Special petroleum laws have been repealed; competition with overseas petroleum companies

has become fierce, and in order to beat the competition in the petroleum industry, stepped-up

efficiency at refineries and development of new technologies have become urgent necessities.

Greater efficiency and new technologies are also required at RFCC facilities. Attention is now

being focused on treatment of coarse feedstock (low-priced feedstock which could not be

treated up to the present) containing large amounts of residual carbon believed to be metals

and coke precursors, and on treatment of RFCC feedstock in which metals, residual carbon and

sulfur have increased in the course of continuous treatment over two years with direct

desulfurization units.

When useful FCC gasoline and LCO are obtained from this coarse RFCC feedstock, the

economy of RFCC equipment improves, the range of crude oil selection at refineries expands,

and international competitiveness is strengthened. It is suspected that in the future, crude oil

will be heavy and large quantities of coke will be produced, but in obtaining FCC gasoline and

LCO, the volume of CO2 discharged from RFCC equipment regenerator tower can be drastically

reduced by using catalyst that produces little coke. This approach would also contribute to the

prevention of global warming.

In light of these conditions, the objective of the present research is to develop an RFCC catalyst

which exhibits the following performance in the RFCC process when desulfurized heavy oil has

been passed through, and it is assumed that this oil is a mixture of Arabian heavy and Rutawi

containing 15ppm or more of metal and 5wt% or more of residual carbon.

FCC gasoline + LCO 64wt% or more

Coke 8wt% or below

Other objectives include greater operational efficiency in the RFCC process, reduced volumes

of CO2 generation, and countermeasures against global warming.

1.1 Search for and improvement of highly active catalysts

With RFCC catalyst, feedstock containing heavy fraction and large quantities of sulfur and

metals such as V or Ni must be processed so that the yield of FCC gasoline and LCO is 64wt%

or more and the coke yield is 8wt% or less. For this purpose, studies have been done on

globular alumina, which is believed to generate little coke, to be used as a substitute for the

conventional needle alumina, and catalyst comprised of globular alumina combined with

substances of different properties and ingredients have been trial-produced and examined.


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1.1.1 Evaluation of catalyst in which the volumes of globular alumina and zeolite were

increased

With the aim of improving catalytic reactivity, catalyst was fabricated in which the volumes of

both globular alumina and zeolite were increased, and catalyst reactions were evaluated.1.1.2 Evaluation of the activity of catalyst in which globular alumina are combined with

regular alumina

To improve catalytic reactivity even further, catalyst was fabricated in which globular alumina

was combined with regular alumina, and catalyst reactions were evaluated.

1.1.3 Impact of zeolite additive

With the aim of increasing the yield of FCC gasoline and LCO even further, the volume of

zeolite additive added to catalyst was increased over the conventional amounts, and catalyst

reactions were evaluated.

1.2 Investigation of the factors affecting catalyst activity

With the aim of attaining high yields of FCC gasoline and LCO, the relationships between

catalyst pore distribution, acid volume and catalytic activity were investigated. The

relationships between catalyst OH base, distribution of alumina in catalyst, and reaction results

were also investigated.

1.2.1 Investigation of catalytic pore distribution

In examining catalyst structure, the inter-relationships among the following were studied:

meso-pore (intermediate pore) positions, catalytic meso-pore and macro pore distributions,

which are believed to be effective in FCC gasoline and LCO production, pore capacity and

reactivity.

1.2.2 Investigation of catalyst acid volumeAmong catalysts yielding outstanding reaction results, the relationship between acid volume and

reaction results was investigated.

1.2.3 Investigation of catalyst OH base

The relationships between catalyst reaction results and OH base strength, which is related to

catalyst acid strength, were investigated.

1.3 Examination of catalyst industrial production methods

Industrial production methods were investigated in order to establish a method for production,

on industrial scale, of catalyst developed on the laboratory scale. In the investigation of

industrial production methods, attention was focused on catalyst composition and on uniformity

in catalyst structure during production testing and on stability during catalyst spray drying.Stability during the catalyst washing process was also considered.

1.4 Determination of catalyst practical performance

Metal resistance, hydrothermal resistance and wear resistance of manufactured and tested

catalyst were investigated in consideration of use of the catalyst in practical equipment.


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2. Results of empirical research and analysis thereof2.1 Search for and improvement of highly active catalyst

2.1.1 valuation of catalyst in which the volumes of globular alumina and zeolite were

increasedIn commercial catalyst , as shown in Figure 2.1-1, because there are few meso-pores, primary

cracked oil produced by cracking of heavy feedstock stagnates in the pores and coke is

generated. Consequently, in order to curtail coke formation and have FCC gasoline + LCO

produced, in the catalyst targeted for development, also shown in the Figure, it is important to

increase meso-pores of uniform size so that primary cracked oil, which can be produced by

cracking feedstock, can be quickly cracked into gasoline and LCO without stagnating in the

pores. As shown in Figure 2.1-2, these meso-pores produce uniform grains. This production

can take place because when grains agglutinate, cavities which can produce uniform grains

also become uniform.

Commercial catalystCoke

Macropore

Feedstock

Meso-pore

GasolinePrimary cracked oil

Development target catalyst

Meso-pore Primary cracked oil

GasolineFeedstock

LCO

Macropore

Figure 2.1-1 Comparative outline of pore structure of developmenttarget catalyst and commercial catalyst

Commercial catalyst

Silica Needle lumina

Non-uniformpores

Developmenttarget Catalyst

Development target catalyst

Silica Alumina Globular alumina

Meso-pore Uniform pore

Meso-pore Meso-pore

Figure 2.1-2 Outline of preparation of alumina having uniformmeso-pores

For this reason, catalyst manufacture takes place in which globular alumina containing uniform

grain size is used. Using I4-05 catalyst, developed in 1998, as a reference for comparison,

percentages of increases in globular alumina and zeolite are presented in Table 2.1-1.


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Table 2.1-1 Volumes of added globular alumina and zeolite

Item/ Catalyst I4-05 I4-10 I4-11 I4-12

Globular alumina (wt%) Standard +10 +7 +9

Zeolite (wt%) Standard +3 +5 +6

The activity of the newly prepared catalyst was evaluated by means of the microactivity test

(MAT). Prior to activity evaluation, vanadium and nickel were added to the catalyst, and it was

subjected to steaming and to pseudo-equilibrium treatment. The properties of the feedstock

used in activity evaluation are given in Table 2.1-2. The feedstock used satisfies the property

requirements ultimately targeted.

Table 2.1-2 Properties of feedstock used in evaluation of catalyst activity

Item/ Feedstock Reaction evaluation feedstock

Density (15%) 0.936

Sulfur component (wt%) 0.51

Residual carbon component (wt%) 5.9

Metal component (ppm) 15

The results of evaluation of catalyst reactions are shown in Figure 2.1-3. It was found that

when three times as much globular alumina, as opposed to zeolite, has been added to I4-10

catalyst, the final targets, namely FCC gasoline + LCO yield of 64wt% or more and coke yield of8wt% or less, are satisfied. It was also found that I4-10 catalyst yields better results that the

nventional I4-05 catalyst. The mechanism behind this pattern is believed to be as follows.

When the volume of globular alumina added to catalyst is increased, meso-pores (intermediate

pores) increase; and when the feedstock (heavy oil) undergoes adequate primary cracking in

the pores, the yields of FCC gasoline and LCO increased because the primary cracked oil,

produced in large volume in the meso-pores, is cracked smoothly with zeolite, which has been

increased.

The reason that the coke yield increases only slightly even though the FCC gasoline + LCO

yield has been increased is that the feedstock is cracked smoothly in the meso-pores, which

have increased, and primary cracked oil does not stagnate inside the pores.


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7065

60

55

+10 +15

Conversion rate (wt%)

+5-10 -5

50

FCCgasoline+LCO

(wt%)

Target value

64

10

8

6

4

+10 +15+5-10 -5

2

Coke

wt%

I4-10:I4-11:I4-12:I4-05

Target value

Standard


:

Standard

Figure 2.1-3 Evaluations of reactions with catalysts of increasedglobular alumina and zeolite

2.1.2 Evaluation of the activity of catalyst in which globular alumina are combined with

regular alumina

With the aim of further improving catalyst activity, studies were done on combinations of

globular alumina and regular alumina. Percentages of added globular alumina and regular

alumina are shown in Table 2.1-3.

Table 2.1-3 Percentages of globular alumina and regular alumina added to catalyst

Alumina type / catalyst Commercial catalyst I4-13 catalyst I4-14 catalyst

Globular alumina (wt%) 0 12 6

Regular alumina (wt%) Standard +5 +11

The results of evaluations of reactions are shown in Figure 2.1-4. It was found that as the

percentage of globular alumina increases, the yield of FCC gasoline + LCO escalates and the

coke yield declines. We see that when the volume of added globular alumina is 12wt%, the

target values are satisfied. One reason for this is ascribed to the fact that feedstock is cracked

smoothly by meso-pores, which are created by globular alumina, so that results are improved.

With large volumes of regular alumina, uniform meso-pores cannot be easily formed among

catalyst pores, the feedstock does not disseminate smoothly, and reaction results decline. And

when regular alumina is used, it is believed that because the pores are small, L acid in alumina

increases relatively, which results in overcracking by acid; coke yield escalates and the yield of

FCC gasoline + LCO drops to a low level.


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7065605

Standard +1 +15Conversion rate (wt%)

+5-10 - 550FCCgasoline+LCO

(wt%)

Target value

64

1 864

+1 +15Conversion rate (wt%)

+5- 10 -52

Coke(wt%)

: I4-13:I4-14Target value

Standard

Cmmercialcatalyst:

Figure 2.1-4 Evaluations of reactions with catalysts in which globularalumina and regular alumina are combined

2.1.3 Impact of zeolite additiveWith the aim of further increasing the yield of FCC gasoline and LCO, studies were undertaken

in which the volume of zeolite added to catalyst was increased over the conventional level.

Volumes of zeolite added to catalyst are presented in Table 2.1-4.

Table 2.1-4 Volumes of zeolite added to catalyst

Item / Catalyst name I4-13 catalyst I4-18 catalyst

Zeolite volume (wt%) Standard +10

The results of evaluations of catalyst reactions are given in Figure 2.1-5. We can see thatwhen the volume of zeolite added is increased 10wt%, the yield of FCC gasoline and LCO

drops and coke yield increases. Because zeolite has been increased 10wt%, FCC gasoline

and other light, primary products are overcracked. Concurrently, opportunities for direct

cracking of feedstock by zeolite increase because of the large volume of zeolite added to the

catalyst, the yield of FCC gasoline and LCO drops, and coke yield increases.

7 656055

+10 +15Conversion rate (wt%)

+5-550FCC

gaso

line+

LCO

(wt%)

Target value64

1210

6

+10 +15+5-10 -5

Co

ke

(wt%)

:I4-13:I4-18

Target value


Standard Standard

Figure 2.1-5 Impact of added zeolite volume on reaction results


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2.2.1 Investigation of catalytic pore distribution

The impact of pore distribution on the results of catalytic reactions was investigated. The pore

distribution of a typical developed catalyst is illustrated in Figure 2.2-1. It was found thatcatalysts having meso-pores, which are intermediate pores in the vicinity of 100, produce

favorable results.

10 100 1000 10000 100000Pore diameter ()

Logdifferential

porecapacity(ml/g)

Developed catalyst

Commercial catalyst

Figure 2.2-1 Pore distribution in developed catalyst

Table 2.2-1 shows the percentages of pore capacity in I4-10 catalyst, which produced the best

reaction results, and in catalysts on the market with pore sizes ranging from 40 ~ 400, 400 ~2000 and 2000 ~ 18000. As indicated under reaction results in section 2.1, it was found

that developed catalyst of high FCC gasoline + LCO yield had extensive meso-pore capacity

between 40 and 400.

Table 2.2-1 Distributions of pore diameter in developed catalyst and commercial catalyst

Pore capacity percentage/

Catalyst name

I4-05 catalyst I4-10 catalyst I4-13 catalyst Commercial

catalyst

40 400 (%) 26 33 29 21

400 2000 (%) 38 40 36 472000 18000 (%) 36 27 35 32

2.2.2 Investigation of catalyst acid volume

In order to investigate the factors behind catalytic activity, the acid volume of developed catalyst

was measured by ammonia adsorption heat, and the results are given in Figure 2.2-2. In light

of these results and the results of a search for and improvement of catalyst as discussed in

section 2.1, no clear relationship between acid volume and yield of FCC gasoline + LCO, or

coke yield, could be recognized. However, in view of the fact that the greatest volume of

adsorption heat is in the I4-10 catalyst, which produces the highest yield of FCC gasoline + LCO,

it is evident that acid must be added to catalyst to some extent in order to improve upon a yield

of 64wt% or more for FCC gasoline + LCO.


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0

20

40

60

80

100

120140

160

180

200

0 200 400 600 800 1000NH3 adsorption volume (10-6mol/ g)

NH3adsorptionheatvolum

e(kJ/mol

I4-05

I4-10

I4-13

CommercialCatalyst

Figure 2.2.2 Measurements of ammonia adsorption heat in catalyst

2.2.3 Investigation of catalyst OH base

Since it is suspected that numerous OH bases are included in catalysts that have large

quantities of solid acid, catalyst OH bases were determined by IR measurements.

Measurements of OH bases by IR in the I4-10 catalyst, which produced favorable results, are

presented in Figure 2.2-3. In the figure, a number of OH base peaks originating from solid acid

or water can be observed, and the peak near 3600 cm-1, which is believed to be a solid acid

OH base, is also high.

0.70.80.91

1.11.21.31.41.51.61.7

2800300032003400360038004000

Absorb

Wave number (cm-1)

Figure 2.2-3 Measurements of OH base by IR of I4-10 catalyst


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In addition to I4-10 catalyst, OH base measurements were taken for a number of other catalysts

of outstanding reactivity, and Table 2.2-2 presents the results of comparisons of peak strength

near 3600 cm-1. From these results, plus the results of evaluations of catalyst reactions, it was

learned that there is not much of a correlation between OH base strength and reaction results.It is suspected that pore distribution has a strong impact on reaction results. However, in view

of the fact that the OH base peak strength is highest for I4-10 catalyst, which produces the best

reaction results, although results are the same as measurements by ammonia adsorption heat

mentioned earlier, it was discovered that OH base, which is a solid acid, is required to some

extent in addition to pore distribution in order to improve still further the yield of FCC gasoline +

LCO.

Table 2.2-2 Strength of OH base in developed catalyst

I4-05 catalyst I4-10 catalyst I4-13 catalyst Commercial

catalystOH base strength (-) 0.115 0.156 0.028 0.135

2.2.4 Examination of alumina distribution in catalyst

An investigation was undertaken to discover how alumina becomes distributed in catalyst when

globular alumina has been added. Measurements by EPMA of alumina distribution in catalyst

revealed that large alumina clusters are distributed more widely in I4-10 catalyst to which

globular alumina has been added than in commercial catalyst. In catalyst of high reactivity, it is

suspected that large clusters of globular alumina are scattered widely and that pores effective in

reactions are formed.


Industrial production methods were investigated in order to establish a method for production,

on industrial scale, of catalyst developed on the laboratory scale. In the investigation of

industrial production methods, attention was focused on catalyst composition and on uniformity

in catalyst structure during production testing, and on stability during catalyst spray drying.

Stability during the catalyst washing process was also considered.

2.3.1 Examination of catalyst composition and catalyst structure

An investigation was made to determine if catalyst could be produced on an industrial scale

without problems and according to specifications. As a result of the catalyst search, I4-10

catalyst, which yielded the best results, was used as a basis in testing of catalyst production.

Catalyst specifications and the composition and property values of manufactured and tested

catalyst are shown in Table 2.3-1. The specifications and property values of this catalyst fall

within the permissible range of variance from specifications, and it was found that there were no

problems with catalyst composition or structural uniformity at the time of production testing.


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Table 2.3-1 Composition and properties of test produced catalyst

Specification Test produced catalyst

CompositionTiO2 (wt%) Standard +0.1

RE2O3 (wt%) Standard +0.2

Na2O (wt%) Standard -0.08

Al2O3 (wt%) Standard +1.5

Ignition loss (wt%) Standard -1.2

Physical property surface area (m2/g) Standard -4

Matrix surface area (m2/g) Standard -10

Zeolite surface area (m2/g) Standard +14

Apparent bulk density (g/ml) Standard +0.04

Pore capacity (g/ml) Standard +0.01Mean grain size ( m) Standard +2

2.3.2 Examination of catalyst bulk density and stability in grain size during spray drying

If conditions change during spray drying of catalyst, cavities are created in the catalyst and

catalyst grain sizes become disparate. When large cavities are produced in the catalyst and

grain sizes become disparate, the catalyst becomes weak in mechanical strength, and the flow

condition of catalyst in practical equipment becomes poor, which in turn adversely affects

reaction results. Accordingly, an investigation was made to ascertain the possibility of

production stable in terms of apparent bulk density and grain diameter. Temporal changes in

apparent bulk density and grain diameter of catalyst during catalyst test production are

presented in Table 2.3-2. At each stage of test production, changes were within permissiblelimits, and it was concluded that during spray drying, catalyst physical properties are stable and

there are no problems.

Table 2.3-2 Temporal changes in apparent bulk density and in grain diameter during

catalyst test production

Apparent bulk density (ml/g) 80 m or less (wt%)

Early term Standard StandardStandard Standard

Middle term Standard -0.01 Standard +1.4

Standard Standard -3.7

Late term Standard -0.02 Standard -0.5

Standard -0.02 Standard -1.9

2.3.3 Examination of stability during catalyst washing

Upon completion of spray drying of catalyst, the catalyst must be washed and poisonous

ingredients in catalyst, Na2O and SO4, must be removed. Unless such impurities are below a

threshold value, during catalyst application they will react with zeolite or matrix, which are active

ingredients, producing a drop in catalyst activity. For this reason, temporal changes in the

concentrations of these impurities during catalyst washing were investigated. The temporal

changes in Na2O and SO4 during washing are presented in Table 2.3-3. Throughout all

catalyst production testing, changes in both Na2O and SO4 were below the reference value, and

it was concluded that there are no problems in washing out the impurities.


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Table 2.3-3 Temporal changes in Na2O and SO4 during catalyst washing

Na2O (wt%) SO4 (wt%)

Early term Standard -0.05 Standard -0.19

Middle term Standard -0.08 Standard -0.23Late term Standard -0.05 Standard -0.17


Metal resistance, hydrothermal resistance and wear resistance of produced and tested catalyst

were investigated in consideration of use of the catalyst in practical equipment.

2.4.1 Metal resistance

When catalyst is used in practical equipment, V and Ni in feedstock accumulate on catalyst due

to catalyst reaction and reproduction, and the catalyst is gradually poisoned. When the metal

resistance of catalyst is low, the catalyst rapidly deteriorates and reaction output declines.

Accordingly, two types of catalyst were produced in which the quantities of V and Ni retained in

each were varied; the catalysts were then subjected to steaming and the metal resistance of

each was examined through evaluations of catalyst reactions. The results of evaluations of

metal resistance in test-produced catalyst are given in Figure 2.4-1.

These results indicated that the drop in reaction output, as opposed to V and Ni poisoning, was

slight in the test-produced catalyst, and that the metal resistance of the test-produced catalyst is

high in comparison to commercial catalyst.

+10

1,000 2,000 3,000 4,000 5,000

V + Ni (ppm)

Commercial catalyst

Test-produced catalyst

Standard

+20

Conversionrate(wt%

)

Standard

Standard

Figure 2.4-1 Metal resistance of test-produced catalyst

2.4.2 Hydrothermal resistance

In the regeneration tower of practical equipment, coke produced on catalyst by reactions is

burnt; the reproduction tower becomes high in temperature; hydrogen included in the coke is

burnt, and a vapor ambient is created. When the hydrothermal resistance of catalyst is low,

the catalyst structure is destroyed in a high-temperature, vapor ambient and surface area

declines, causing reactivity to drop so that targeted output can no longer be attained. For this

reason, hydrothermal resistance is required in catalyst so it can withstand a high-temperature

vapor ambient.


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In order to determine the hydrothermal resistance of the test-produced catalyst, the catalyst was

subjected to steaming at the high temperatures of 773C or 732C, and its reactivity was then

evaluated. The results of this evaluation are shown in Figure 2.4-2. It was found that the

hydrothermal resistance of the test-produced catalyst is superior to that of commercial catalyst,and that there are no problems.

Standard

+20

Conversionrate(wt%)

720 730 750 760 780

Treatment temperature (C)

740 770

Commercial catalyst

Test-produced catalyst

+10

Standard

Standard

Figure 2.4-2 Hydrothermal resistance of test-produced catalyst

2.4.3 Wear resistance

In the equipment, RFCC is circulated between the reaction tower and regeneration tower and

wear is produced by collisions between the catalyst and equipment and by collisions among

catalyst grains. When catalyst wear is extensive, large volumes of catalyst are introduced into

the equipment, which makes for poor economy. Accordingly, the wear resistance of the

test-produced catalyst was measured. To measure wear resistance, a fixed quantity of catalyst

was filled into a cylindrical container, air was introduced from the bottom of the container at

close to the speed of sound so that the catalyst grains would flow violently and collide; the

catalyst was thus pulverized into powder form and powder scattering from the top of the cylinder

was collected, and its volume measured. The results of this wear resistance test are presented

in Table 2.4-1.

It was found that the test-produced catalyst presents no problems in wear resistance, since the

scattered volume of test-produced catalyst was less than that of commercial catalyst.

Table 2.4-1 Measurements of wear resistance in test-produced catalyst

Test-produced catalyst Commercial catalystCatalyst scattering volume (wt%/30h) 3 4

3. Results of Empirical Research3.1 Search for and improvement of highly active catalyst

With the aim of increasing the yield of FCC gasoline + LCO and decreasing coke yield, various

studies were done on zeolite and globular alumina, which causes meso- pores (intermediatepores) to form in catalyst. As a result, it was found that at bench plant the developed catalyst

satisfied the target values of the present research.


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Various factors affecting catalyst activity, including catalyst pore distribution, acid volume, OH

base and alumina distribution, were investigated for the purpose of escalating catalyst reaction

output. It was discovered that favorable reaction results are obtained from catalyst havingmany meso-pores, that is, intermediate pores in the vicinity of 100. It was also found that

high yields of FCC gasoline + LCO are obtained from catalyst having a meso-pore capacity of

between 40 ~ 400. Another finding is that the catalysts producing favorable reaction results

are ones that have large clusters of alumina spread widely throughout which cause pores to

form that are effective in reactions.


Studies were done on catalyst composition and structure, on stability during spray drying and on

stability during washing, all items of concern in industrial manufacture of catalyst, and it was

found that there were no problems in any instance.


Studies were done, in practical terms, on the metal resistance, hydrothermal resistance and

wear resistance of developed catalyst, and it was found that in every instance, the results were

better than with commercial catalyst and that no problems were encountered.

4. Synopsis

In the present R&D on catalyst for catalytic cracking of heavy oil containing high levels of metal

and residual carbon, studies were done on catalyst manufacture on an industrial scale, and as a

result of evaluations of reactions, using bench equipment, it was found that catalytic

performance reached targeted values. To gain a more solid evaluation of developed catalyst inthe future, short-term evaluations will be made of applicability, using practical equipment, in

relation to catalyst stripability (removal of produced oil adhering to catalyst), which cannot be

evaluated easily with laboratory equipment, and catalyst service life.

In reference to final targets, the applicability of catalyst obtained in studies of industrial

manufacturing methods will be evaluated, the factors affecting activity will be investigated and

other steps will be taken to advance the development of catalysts.

Copyright 2000 Petroleum Energy Center all rights reserved.

Documents

R&D on Catalyst for Cracking of Heavy Oil