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Distillate production in Queensland: Refinery operations and economics
Energy Vol. II. No. 3, PD. 245-251. Printed in Great Britain.
0360-5442/86 $3.00 t .MJ 0 1986 Pergamon Press Ltd
1986
DISTILLATE REFINERY
PRODUCTION IN QUEENSLAND: OPERATIONS AND ECONOMICS
F. K. MAK and R. B. NEWELL Department of Chemical Engineering, University of Queensland, St. Lucia. Qld. 4067 (Received 8 January 1985; receivedfor publication 17 April 1985)
Abstract-To meet increasing demand for distillate, the refiner has to commit capital to provide incremental capacity or new processing facilities, especially in hydrocracking, delayed coking and visbreaking. The incremental cost of distillate production has heen determined in terms of the increase in total cost or in crude oil usage per tonne of extra distillate. We use a model of the oil-refining and transportation sectors to arrive at the optimal selection of capital investment, refinery configuration, crude slate and vehicle fleet.
INTRODUCTION
We present the findings of a study on distillate production in the Queensland refining sector. The study has been prompted by problems perceived in distillate production to meet future requirements. If national demand continues to grow as forecast, there will be a serious shortfall, which the present national aggregate refinery will fail to meet. In the State of Queensland, the problems of distillate production are serious, since a current shortfall exists and Queensland is the place where major development projects will place the distillate demand growth rate above the national distillate average. A significant proportion of the current demand for distillate in Queensland is met by import from southern refineries. A report by the National Energy Advisory Committee’ predicted that the demand would increase at more than 3%/annum for the next 5-10 yrs. Distillate is used for industrial and transport purposes, The portion of current demand associated with automobile transport is only about 10%. We consider the increase in distillate demand to be mainly due to nonautomobile usage. The response of the Queensland refining sector to meeting a set of product and transportation demands is quantified by using a model of the integrated refining-transportation sector. The type of process units and capacity called on-stream are examined, especially heavy-end processing units like the visbreaker and delayed coker to maxim& distillate production. The economics of capital investment, incremental costs and the optimal slate of transport-fuels are obtained. METHOD
OF INVESTIGATION
The process units available in the Queensland oil-refining sector are listed in Table 1. Consumptions of the various refinery products are given in Table 2, these being extracted from the 1980-81 AIP publications. ’ The base distillate demand of 3.38 kilotonnes/day was increased in the range 50-300% and up to the feasibility limits of the optimisation. The automobile distillate portion was separated from the demand but its quantity was determined, as with the other two transport fuels (gasoline and automotive lpg), by optimisation. The RON/MON values for the regular and premium grades are 98/87 and 89/82, respectively, while the lead level in both was set at 0.53 g/l maximum. The model is free to select the optimal feed from the crudes available to the Queensland refining sector, shown in Table 3 with assumed 1980 prices. A price of zero was assigned to high-sulphur fuel oil, for simplicity of the exercise. A dummy cost of $70/tonne for inplant hydrogen was also used. It is recognised that the hydrogen cost affects the selection of refinery configuration and thus the total costs of production. The following are the new process units made available to the model: hydrotreater, hydrocracker, isomeriser, deasphalter, delayed coker and visbreaker. Table 4 lists the cases selected for study, according to the constraints placed on unit availability and capacity. The hydrotreater upgrades the naphtha and catcracker feed, as distinct from the desulphuriser which treats the light gas oils for product blending. 245
F. K. MAK and R. B. NEWELL
246
Table 1. Process unit and capacity. Unit
Capaciry Kt/d
Crude Unit
12.30
Vacuum distiller
9.30
Catcracker
4.86
Alkylator
0.75
Desulphuriser
1.17
Low pressure reformer
1.07 I I
High pressure reformer
1.96
Table 2. Consumption of refinery products. Consumption Kt/day
Product
Non-automotive lpg
0.19
KeIYXt?lIl?
0.06
Avtur
0.71
Non-automobile distillate
3.25
fuel oils (industrial + low sulphw fuel oils)
2.45
high sulphur fuel oil (bunker)
0.36
industrial diesel
0.13
Table 3. Crude oil and assumed prices.
r Type
Price, S/kt (1980)
Gippsland Arab light Minds Attaka
170.9 162.8 176.3 201.2
Table 4. Cases studied.
I
-1 Case
A:
Existing process units
Case
B:
Existing process units + capacity increment
Case
c:
Existing
process
units + new units + capacity
increment
~
Case
D:
Existing process units + hydrocracker + capacity increment
Case
E:
Existing process units + hydrocracker + isomeriser + capacity increment
Case f:
I
Existing process units + hydrocracker + delayed coker + capacity increment 1
Distillate production in Queensland
241
RESULTS
General observations of unit behaviour For Case A, the existing refining sector was not able to produce the base demand of distillate. This result corresponds to the current situation in which distillate is imported from the southern states. For Case B, Fig. 1 shows the required capacity at different levels of distillate production. By allowing capacity increment to the existing units, a distillate production up to 190% increase of current demand is achieved. The following units required uprate: crude unit (by 70%), desulphuriser (by 30%) and low-pressure reformer (by 20%). The catcracker, alkylation and vacuum units were found to be adequate. The required capacity for the hydrotreater was determined. For Case C, Fig. 2 shows that distillate production up to 370% increase of current demand was achieved when the new units, viz. hydrocracker, isomer&r, delayed coker and visbreaker were installed, and existing units were allowed to assume incremental capacity. While the crude unit consistently called for capacity increase, the low-pressure reformer and desulphuriser required significant uprate at around the maximum distillate production mark. The hydrocracker came on-line from around the 50% distillate increase point, the delayed coker from the 150% point, while the visbreaker and isomeriser were required at the upper limit of distillate production. Capacities for the new units were determined. In all cases, the alkylation unit and catcracker were shut down at high distillate production levels. Identical results were obtained for the D and E cases (see Fig. 3). This was not unexpected since the two differed only by an isomeriser that was found to be unnecessary. A distillate production up to 340% increase over current demand was achieved. For Case
DISTILLATE PRODUCTION
INCREASE -
% CURRENT DEMAND Fig. I.Required
Nomenclature for Figs. 1-4 CU crude unit DS LR AY CC I-K HT DC IS
desulphuriser low pressure reformer alkylation unit catcracker hydrocracker hydrotreater delayed coker isomer&r
capacity of process units (Case B)
F. K.
248
MAKand R. B. NEWELL
240 220 200 180 L; 160 ,” u” 140 5 lJ&120 f L 100
”
50 100 I.58 MO 250 300 39 4oI DISTILLATE PRODUCTION INCREASE % CURRENT DEMAND
Fig. 2. Required capacity of process units (Case C)..
F, a maximum distillate production of 340% increase was obtained, with the delayed coker operating from around the 150% distillate increase point (see Fig. 4). General observation of product compositions
For Case B, more light overheads (C2, C3, C4), naphtha, light gas oils and kerosene are produced as the crude unit steps up capacity. These form the main components of the
DISTILLATE PRODUCTION INCREASE X CURRENT DEMAND
Fig. 3. Required capacity of process units (Cases D and E).
Distillate production in Queensland
249
2oc 18C
HT
_-
4c 2c C DISTILLATE PRODUCTION INCREASE X CURRENT DENAND
Fig. 4. Required capacity of process units (Case F).
distillate (kerosene, light gas oils), refinery fuel (C2, C3, C4) and gasoline (C4, naphtha). In the gasoline, the C4, naphtha and reformate are used in increasing amounts to substitute for catcracked gasolines as the catcracker turns down at high distillate production. The fuel oils, i.e. industrial and high-sulphur fuel oils also change from predominantly catcracked products (cycle oils, slurry oils) to blends of long and short residues. For Case C, the crude unit and hydrocracker produce increasing amounts of light overheads, kerosene, light gas oils and naphtha. As the catcracker reduces capacity, its products, such as cycle and slurry oils and catcracked gasolines are replaced by the products from the crude unit and hydrocracker. With the delayed coker and visbreaker on-line, more light and heavy gas oils are produced together with residuals and coke for blending in distillate, fuel oils and refinery fuel. For the other intermediate cases, the variation in product compositions is similar to the situations described. General observations of transport-fuel slate
The three transport-fuels are gasoline (premium and regular grades), automotive lpg and distillate. Their fuel efficiencies are specified for the cars/wagons, utilities/vans, rigid trucks and articulated trucks. The model was required to produce the optimal transport-fuel slate to meet the specified VKT (vehicle-km travelled) demands shown in Table 5. Results of all Table 5. Transportation demands. Vehicle
Class
and motor cycles Cars, wa@zms Utilities
and vans
35.26 x 1P6 9.43 x 1c6 4.52 x 106
Rigid trucks Articulated
VKT, km/day
trucks
1.77 x lc16
250
F. K. MAK and R. B. NEWELL
GASOLINES 35
b?
30
+ 3 .
9 w 5
10 AUTOMOTIVE
0
PRODUCTION
400
300
200
100 DISTILLATE
LPG
INCREASE
- % CURRENT
DEMAND
Fig. 5. Relative yields of gasolines and automotive Ipg in the transport-fuel slate.
cases showed that the optimal slate excludes automotive distillate, which observation is understandable in a competitive distillate situation. Premium and regular gasolines are used in most cases for all classes of vehicles although at high distillate production, regular substitutes for premium. Automotive lpg is used for only cars and wagons, but not at high distillate production. Figure 5 shows the yields of total gasoline and automotive lpg making
C
I
100 DISTILLATE
200 PRODUCTION
% CURRENT
300 INCREASE
DISTILLATE -
DEMAND
Fig. 6. Incremental cost of distillate production.
PRODUCTION x CURRENT
INCREASE
-
DEMAND
Fig. 7. Incremental crude oil usage in distillate production.
251
Distillate production in Queensland Table 6. Economics of distillate production. Max. increase in distillate production % current demand
27.2
T---
Increase existing
capacity unirs
of
190
Incremental $11 dl;ti:late 300
Costs t Crude t distillate 3.2
153.5
Irxrease capacity existing units + hydracracker
of
2.3
i79.2
Increase capacity existing units + hvdrocracker + d.
of
;.
407.5
Increase
existing new units
3
coke1
capacity of units + all
up the optimal slates in the cases considered. Thus, in order to meet the VKT demands at increased distillate production, more crudes have to be processed by the refinery. Economics
Figures 6 and 7 show the incremental cost and crude oil usage with distillate production in the various cases. The economics are summarised in Table 6. Thus, the incremental costs range from $260-300/tonne, made up largely of crude oil purchases that amounted to over 90% of the total cost. The most attractive option appears to be uprating of existing units with an investment of $27 X 106.Addition of a hydrocracker increases the capital requirement to $153 X 106. Installation of a delayed coker does not raise distillate production or incremental cost. The corresponding incremental crude oil usage ranges from 3.2-2.3 tonnes/ tonne of distillate. Marginal improvement in the economics is gained by installing further units, viz. a visbreaker and isomeriser. The capital rises to $407 X 106. It is seen that while a visbreaker can achieve a further 30% increase in distillate production in the uprated refinery, the corresponding incremental cost is relatively high at $1800/tonne of distillate. In a separate study on distillate by the Department of National Development and Energy,3 marginal costs in terms of crude/volume of middle distillate for “hydroskimming and conversion refineries” ranged from 2.2-3.2, according to whether Gippsland or Arabian light crude was used. On a weight basis, the equivalent values are about 2.1-3.0 tonnes crude oil/tonne distillate. Thus, these figures are in close agreement with ours. However, no comparison could be made on refinery operations as these were not divulged in the official report. REFERENCES I. National Energy Advisory Council (NEAC), “Petroleum Products-Demand
and Supply Trends in Australia.” Report No. 18, Canberra, Australia, (1982). 2. Australian Institute of Petroleum (AIP) Ltd., “Oil and Australia-the figures Behind the Facts.” Melbourne. Victoria, Australia, (198 1). 3. Department of National Development and Energy, “Oil Refining Technology in Australia-Status and Outlook.” Australian Government Publishing Service, Canberra, Australia (1982).
0360-5442/86 $3.00 t .MJ 0 1986 Pergamon Press Ltd
1986
DISTILLATE REFINERY
PRODUCTION IN QUEENSLAND: OPERATIONS AND ECONOMICS
F. K. MAK and R. B. NEWELL Department of Chemical Engineering, University of Queensland, St. Lucia. Qld. 4067 (Received 8 January 1985; receivedfor publication 17 April 1985)
Abstract-To meet increasing demand for distillate, the refiner has to commit capital to provide incremental capacity or new processing facilities, especially in hydrocracking, delayed coking and visbreaking. The incremental cost of distillate production has heen determined in terms of the increase in total cost or in crude oil usage per tonne of extra distillate. We use a model of the oil-refining and transportation sectors to arrive at the optimal selection of capital investment, refinery configuration, crude slate and vehicle fleet.
INTRODUCTION
We present the findings of a study on distillate production in the Queensland refining sector. The study has been prompted by problems perceived in distillate production to meet future requirements. If national demand continues to grow as forecast, there will be a serious shortfall, which the present national aggregate refinery will fail to meet. In the State of Queensland, the problems of distillate production are serious, since a current shortfall exists and Queensland is the place where major development projects will place the distillate demand growth rate above the national distillate average. A significant proportion of the current demand for distillate in Queensland is met by import from southern refineries. A report by the National Energy Advisory Committee’ predicted that the demand would increase at more than 3%/annum for the next 5-10 yrs. Distillate is used for industrial and transport purposes, The portion of current demand associated with automobile transport is only about 10%. We consider the increase in distillate demand to be mainly due to nonautomobile usage. The response of the Queensland refining sector to meeting a set of product and transportation demands is quantified by using a model of the integrated refining-transportation sector. The type of process units and capacity called on-stream are examined, especially heavy-end processing units like the visbreaker and delayed coker to maxim& distillate production. The economics of capital investment, incremental costs and the optimal slate of transport-fuels are obtained. METHOD
OF INVESTIGATION
The process units available in the Queensland oil-refining sector are listed in Table 1. Consumptions of the various refinery products are given in Table 2, these being extracted from the 1980-81 AIP publications. ’ The base distillate demand of 3.38 kilotonnes/day was increased in the range 50-300% and up to the feasibility limits of the optimisation. The automobile distillate portion was separated from the demand but its quantity was determined, as with the other two transport fuels (gasoline and automotive lpg), by optimisation. The RON/MON values for the regular and premium grades are 98/87 and 89/82, respectively, while the lead level in both was set at 0.53 g/l maximum. The model is free to select the optimal feed from the crudes available to the Queensland refining sector, shown in Table 3 with assumed 1980 prices. A price of zero was assigned to high-sulphur fuel oil, for simplicity of the exercise. A dummy cost of $70/tonne for inplant hydrogen was also used. It is recognised that the hydrogen cost affects the selection of refinery configuration and thus the total costs of production. The following are the new process units made available to the model: hydrotreater, hydrocracker, isomeriser, deasphalter, delayed coker and visbreaker. Table 4 lists the cases selected for study, according to the constraints placed on unit availability and capacity. The hydrotreater upgrades the naphtha and catcracker feed, as distinct from the desulphuriser which treats the light gas oils for product blending. 245
F. K. MAK and R. B. NEWELL
246
Table 1. Process unit and capacity. Unit
Capaciry Kt/d
Crude Unit
12.30
Vacuum distiller
9.30
Catcracker
4.86
Alkylator
0.75
Desulphuriser
1.17
Low pressure reformer
1.07 I I
High pressure reformer
1.96
Table 2. Consumption of refinery products. Consumption Kt/day
Product
Non-automotive lpg
0.19
KeIYXt?lIl?
0.06
Avtur
0.71
Non-automobile distillate
3.25
fuel oils (industrial + low sulphw fuel oils)
2.45
high sulphur fuel oil (bunker)
0.36
industrial diesel
0.13
Table 3. Crude oil and assumed prices.
r Type
Price, S/kt (1980)
Gippsland Arab light Minds Attaka
170.9 162.8 176.3 201.2
Table 4. Cases studied.
I
-1 Case
A:
Existing process units
Case
B:
Existing process units + capacity increment
Case
c:
Existing
process
units + new units + capacity
increment
~
Case
D:
Existing process units + hydrocracker + capacity increment
Case
E:
Existing process units + hydrocracker + isomeriser + capacity increment
Case f:
I
Existing process units + hydrocracker + delayed coker + capacity increment 1
Distillate production in Queensland
241
RESULTS
General observations of unit behaviour For Case A, the existing refining sector was not able to produce the base demand of distillate. This result corresponds to the current situation in which distillate is imported from the southern states. For Case B, Fig. 1 shows the required capacity at different levels of distillate production. By allowing capacity increment to the existing units, a distillate production up to 190% increase of current demand is achieved. The following units required uprate: crude unit (by 70%), desulphuriser (by 30%) and low-pressure reformer (by 20%). The catcracker, alkylation and vacuum units were found to be adequate. The required capacity for the hydrotreater was determined. For Case C, Fig. 2 shows that distillate production up to 370% increase of current demand was achieved when the new units, viz. hydrocracker, isomer&r, delayed coker and visbreaker were installed, and existing units were allowed to assume incremental capacity. While the crude unit consistently called for capacity increase, the low-pressure reformer and desulphuriser required significant uprate at around the maximum distillate production mark. The hydrocracker came on-line from around the 50% distillate increase point, the delayed coker from the 150% point, while the visbreaker and isomeriser were required at the upper limit of distillate production. Capacities for the new units were determined. In all cases, the alkylation unit and catcracker were shut down at high distillate production levels. Identical results were obtained for the D and E cases (see Fig. 3). This was not unexpected since the two differed only by an isomeriser that was found to be unnecessary. A distillate production up to 340% increase over current demand was achieved. For Case
DISTILLATE PRODUCTION
INCREASE -
% CURRENT DEMAND Fig. I.Required
Nomenclature for Figs. 1-4 CU crude unit DS LR AY CC I-K HT DC IS
desulphuriser low pressure reformer alkylation unit catcracker hydrocracker hydrotreater delayed coker isomer&r
capacity of process units (Case B)
F. K.
248
MAKand R. B. NEWELL
240 220 200 180 L; 160 ,” u” 140 5 lJ&120 f L 100
”
50 100 I.58 MO 250 300 39 4oI DISTILLATE PRODUCTION INCREASE % CURRENT DEMAND
Fig. 2. Required capacity of process units (Case C)..
F, a maximum distillate production of 340% increase was obtained, with the delayed coker operating from around the 150% distillate increase point (see Fig. 4). General observation of product compositions
For Case B, more light overheads (C2, C3, C4), naphtha, light gas oils and kerosene are produced as the crude unit steps up capacity. These form the main components of the
DISTILLATE PRODUCTION INCREASE X CURRENT DEMAND
Fig. 3. Required capacity of process units (Cases D and E).
Distillate production in Queensland
249
2oc 18C
HT
_-
4c 2c C DISTILLATE PRODUCTION INCREASE X CURRENT DENAND
Fig. 4. Required capacity of process units (Case F).
distillate (kerosene, light gas oils), refinery fuel (C2, C3, C4) and gasoline (C4, naphtha). In the gasoline, the C4, naphtha and reformate are used in increasing amounts to substitute for catcracked gasolines as the catcracker turns down at high distillate production. The fuel oils, i.e. industrial and high-sulphur fuel oils also change from predominantly catcracked products (cycle oils, slurry oils) to blends of long and short residues. For Case C, the crude unit and hydrocracker produce increasing amounts of light overheads, kerosene, light gas oils and naphtha. As the catcracker reduces capacity, its products, such as cycle and slurry oils and catcracked gasolines are replaced by the products from the crude unit and hydrocracker. With the delayed coker and visbreaker on-line, more light and heavy gas oils are produced together with residuals and coke for blending in distillate, fuel oils and refinery fuel. For the other intermediate cases, the variation in product compositions is similar to the situations described. General observations of transport-fuel slate
The three transport-fuels are gasoline (premium and regular grades), automotive lpg and distillate. Their fuel efficiencies are specified for the cars/wagons, utilities/vans, rigid trucks and articulated trucks. The model was required to produce the optimal transport-fuel slate to meet the specified VKT (vehicle-km travelled) demands shown in Table 5. Results of all Table 5. Transportation demands. Vehicle
Class
and motor cycles Cars, wa@zms Utilities
and vans
35.26 x 1P6 9.43 x 1c6 4.52 x 106
Rigid trucks Articulated
VKT, km/day
trucks
1.77 x lc16
250
F. K. MAK and R. B. NEWELL
GASOLINES 35
b?
30
+ 3 .
9 w 5
10 AUTOMOTIVE
0
PRODUCTION
400
300
200
100 DISTILLATE
LPG
INCREASE
- % CURRENT
DEMAND
Fig. 5. Relative yields of gasolines and automotive Ipg in the transport-fuel slate.
cases showed that the optimal slate excludes automotive distillate, which observation is understandable in a competitive distillate situation. Premium and regular gasolines are used in most cases for all classes of vehicles although at high distillate production, regular substitutes for premium. Automotive lpg is used for only cars and wagons, but not at high distillate production. Figure 5 shows the yields of total gasoline and automotive lpg making
C
I
100 DISTILLATE
200 PRODUCTION
% CURRENT
300 INCREASE
DISTILLATE -
DEMAND
Fig. 6. Incremental cost of distillate production.
PRODUCTION x CURRENT
INCREASE
-
DEMAND
Fig. 7. Incremental crude oil usage in distillate production.
251
Distillate production in Queensland Table 6. Economics of distillate production. Max. increase in distillate production % current demand
27.2
T---
Increase existing
capacity unirs
of
190
Incremental $11 dl;ti:late 300
Costs t Crude t distillate 3.2
153.5
Irxrease capacity existing units + hydracracker
of
2.3
i79.2
Increase capacity existing units + hvdrocracker + d.
of
;.
407.5
Increase
existing new units
3
coke1
capacity of units + all
up the optimal slates in the cases considered. Thus, in order to meet the VKT demands at increased distillate production, more crudes have to be processed by the refinery. Economics
Figures 6 and 7 show the incremental cost and crude oil usage with distillate production in the various cases. The economics are summarised in Table 6. Thus, the incremental costs range from $260-300/tonne, made up largely of crude oil purchases that amounted to over 90% of the total cost. The most attractive option appears to be uprating of existing units with an investment of $27 X 106.Addition of a hydrocracker increases the capital requirement to $153 X 106. Installation of a delayed coker does not raise distillate production or incremental cost. The corresponding incremental crude oil usage ranges from 3.2-2.3 tonnes/ tonne of distillate. Marginal improvement in the economics is gained by installing further units, viz. a visbreaker and isomeriser. The capital rises to $407 X 106. It is seen that while a visbreaker can achieve a further 30% increase in distillate production in the uprated refinery, the corresponding incremental cost is relatively high at $1800/tonne of distillate. In a separate study on distillate by the Department of National Development and Energy,3 marginal costs in terms of crude/volume of middle distillate for “hydroskimming and conversion refineries” ranged from 2.2-3.2, according to whether Gippsland or Arabian light crude was used. On a weight basis, the equivalent values are about 2.1-3.0 tonnes crude oil/tonne distillate. Thus, these figures are in close agreement with ours. However, no comparison could be made on refinery operations as these were not divulged in the official report. REFERENCES I. National Energy Advisory Council (NEAC), “Petroleum Products-Demand
and Supply Trends in Australia.” Report No. 18, Canberra, Australia, (1982). 2. Australian Institute of Petroleum (AIP) Ltd., “Oil and Australia-the figures Behind the Facts.” Melbourne. Victoria, Australia, (198 1). 3. Department of National Development and Energy, “Oil Refining Technology in Australia-Status and Outlook.” Australian Government Publishing Service, Canberra, Australia (1982).