Chemistry and Technology of Fuels and Oils, Vol. 32. No. 4, 1996

CURRENT PROBLEMS

REFINERY H Y D R O C A R B O N GASES: R E S O U R C E S AND UTILIZATION

Yu. P. Kopylov, L. I. Vstavskaya, and A. M. Mazgarov

UDC 665.65.002.23

More than five years have passed since the last publication on this subject [1]. With the breakup of the USSR and disruption of traditional relationships, the available resources of light hydrocarbon feedstocks in Russian refineries have been greatly curtailed. The volume of crude oil processing is declining steadily: In 1994, it dropped 38.2 million tons [metric tons] from the 1993 level. Decreases were experienced in practically all refineries, but were particularly acute at the AOOTs [opentype joint stock companies] Ryazan Petroleum Refinery, Omsk Petroleum Refinery, Kreking (in Saratov), and others.* Reductions were also experienced in the volume of petroleum feedstocks charged to secondary processes, with the exception of cat cracking and isomerization. In 1994 at the Omsk refinery, as a part of the KT-1 complex, a cat cracker with a charging capacity of 2 million tons per year went on-line. All of these changes were adequately reflected in the resources of hydrocarbon gases (Table 1), which in 1994 were lower than in 1993 by 1.3 million tons, or 11.7%. The same as in the previous years, the relative amount of gases and "refluxes"t in primary crude oil distillation and naphtha redistillation (constituting half of the total resources of gas) that was taken for further processing remained at a low level (63.8 %); the volume of wet gas directed to further processing amounted to 26.5 %. In accordance with the established fuel balance, 1.8 million tons of wet straight-run gas was used as fuel. Almost all of the gas from catalytic reforming is processed in stabilization sections, in which refluxes are recovered. The average yield of reflux in catalytic reforming in the naphtha upgrading mode is 2.5%, and in the aromatics recovery mode 4%. In most refineries, the absorption-stabilization sections of these units generally operate under nonoptimal conditions, and the takeoff of C 3 and C 4 hydrocarbons with the stabilizer head is low. A considerable part of these hydrocarbons remains in the naphtha and is lost during storage by evaporation. It has been shown [2] that with optimization of the operation of a fractionating absorber in the L-35-11/300 units at the Ryazan and Tuapse ref'meries, the yield of stabilizer head is 3.6-3.1%, with a propane content up to 70% by weight. Gases from distillate hydrotreating, hydrocracking, and toluene hydrodealkylation, with the exception of the hydrogen sulfide, are completely used as process fuel in all refineries. The resources of olefin-containing gases from thermal cracking, cat cracking, and coking were 1.7 million tons in 1994, which was 0.2 million tons lower than in 1993. The average yield of reflux in cat crackers of the 1A/1M, GK-3, and 43-103 types was 7.6%; the yields of wet gas in 43-102 and G-43-107 units were 11.5% and 20.5%, respectively. In 1994, 94.3 % of the wet gas from cat cracking and 100% of the reflux was taken for further processing. Of the wet gas from thermal cracking, 51.5% was processed; the remainder (89.5 thousand tons), mainly from 15/5 type sections, was used as fuel. These gases were completely utilized in further processing in the AO [joint stock company] Novo-Ufa Petroleum Refmery and the AOOTs LUKoil-Permnefteorgsintez and Omsk Petroleum Refinery. Coker gases are used entirely as process fuel in almost all refineries, with the exception of LUKoil-Permnefteorgsintez, where 26.9 thousand tons of this gas are directed to the gas fractionation unit (GFU). Hydrogen sulfide from treatment of coker gases is subjected to further processing. Of the total resources of gases and refluxes from these processes, which in 1994 amounted to 9.8 million tons, 6.8 tons (69.4%) was subjected to fractionation, including gas fractionation, compression, *According to data reported by the refineries for 1993 and 1994. tRussian word reflyuksy; exact meaning in present context unknown--Translator. All-Russian Scientific-Research Institute of Hydrocarbon Feedstocks (VNIIUS). Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 4, pp. 19-20, July-August, 1996. 0009-3092/96/3204-0175515.00 9

Plenum Publishing Corporation

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TABLE I Resources, 1000 tons Hydrocarbon gases

i i

1993

For all refineries of the Russian Federation inc!uding pnmary crude oil distillation and naphtha redistillation

1994

increase (+) or decreases ( - ) in 1994 - 1326,8

11159,8

9833,0

5599,5

4847,1

-752,4

catalytic reforming

2328,6

2067,8

-261,8

distillate hydrotreating thermal cracking cat cracking

1125,7 384,9 1285,2

1038,3 263,2 1304,1

-87,4 - 121,7 + 18,9

266.6 84,3 29,3

167.5 98, i 1,1

-99.1 + 13,8 -26,2

15,6 6,4 -

10.2 5,9 3,8

6,4

2, 1

-5.4 -0.5 +3.8 - 4,3

cokmg.

]somerlzation demethylation of toluene Parex process obtained from outside isobutane from ~as processing plants butene-isobutylene fraction from synthetic rubber plants

TABLE 2 Resources of hydrocarbon gases, 1000 tons directed to fractionation subject to (percentage relative to total fractionation total subject to fractionation ts listed in ~arentheses)

Refinery or plant

Joint stock companies Ufa Petroleum Refinery Novo-Ufa Petroleum Refinery Ufaneftekhim Salavamefteorgsintez Novokuibyshevsk Petroleum Refinery

268,1 542,2 618,2

191,4 353.3 367,1

86,1 (45,0) 293,9 (83,2) 312.6 (85,1)

605,2

443.6

428,6 (96,6l

Syzran Petroleum Refinery

384,6 361,9

287,7 245.0

172,2 (59,9) 190,4 (77,7)

Angarsk Petrochemical Company Achinsk Petroleum Refinery NORSI Nizhnekamskneftekhim

854,8

719,3

403,1 (56,0)

414,6 710,8 20,3

330,0 527,8 20,3

323,1 (97.9) 265.6 (50,3) 0 (0)

175,0 170,7 51,9

108,7 (62,1) 15,8 (9,3) 0 (0)

Open-type joint stock companies Kuibyshev Petroleum Refinery LUKoiI-Volgogradneftepererabotka Komsomol'sk Petroleum Refinery Krasnodarnefteorgsintez Moscow Petroleum Refinery Yaroslavnefteorgsintez Orsknefteorgsintez LUKoiI-Permnefteorgsintez Ryazan Petroleum Refinery Kreking (city of Saratov) Tuapse Petroleum Refinery Ukhta Petroleum Refinerv Khabarovsk Petroleum Refinery Kirishinefteorgsintez Omsk Petroleum Refinery

328,1 302,4 54,0 68,1

47.5

592,5 433,3 463,2

418,2 329,8 228,8 276,4

357,6 309.5 124,9 239,6

455.0

299,2

231,7 (77,4)

94,3 61,7 101,4

37,0 32,9 78,5

3,7 (10,0) 12.9 (39,2) 0 (0)

140,2 590.7 1088,5

129,1 401,1 676,1

129,1 (100) 363,9 (90,7) 553,3 (81,8)

258,9

21.0 (44,2)

(85,5) (93,9) (54,6) (86,7)

Note. No data for Groznefteorgsintez Production Association.

domestic needs, and petrochemistry; also, 4.9 million tons (72.4%) was directed to central gas fractionation units. The resources of gases and their utilization in each refinery in 1994 are listed in Table 2. A number of refineries make maximum use of gas resources. Among them are the Khabarovsk ref'mery 100%, Achinsk refinery 97.9 %, Yaroslavnefteorgsintez 93.9 %, Salavatnefteorgsintez 96.6 %, and Kirishinefteorgsintez 90.7 %. As before, the level of utilization of gases at the Kreking AOOT was low (10%), as was also the case for LUKoil-Volgogradneftepererabotka (9.3%) and a number of other refineries; this reflects a lack of capacity for gas processing. In the petroleum refineries of Russia, 29 gas fractionation units are operating (gas fractionation units and absorption/gas fractionation units) with a total charging capacity of 9.0 million tons/yr, including 12 units for processing saturated feeds, 13 176

units for processing unsaturated feeds, and 4 two-section units. It should be noted that 75% of these units are obsolete and in poor condition. The capacity of gas fractionation units for processing saturated gases is 50% utilized, that for unsaturated gases 43%. The low level of capacity utilization can be attributed to the shortage of feed. The best gas fractionation units in terms of recovery and purity of hydrocarbon products are those operating at the Omsk refinery, Kirishinefteorgsintez, the Achinsk refinery (as a section of the LK-6u unit), and the Moscow refinery (as a section of the G-43-107 cat cracker). The total LPG production in refineries of the Russian Federation in 1994 was 2 million tons, i.e., 0.2 million tons lower than in 1993. The output of refluxes for central gas fractionation units also dropped, amounting to 615.2 thousand tons in 1994. The volume of total commercial production of LPG in the refineries in 1994 was 1.28 million tons, which was 18% tower than in 1993. The production of alkylate as a high-octane component of gasoline is decreasing from year to year, owing to the retirement of worn-out and obsolete equipment. In 1994, alkylate production was 178.6 thousand tons, or 28.4 thousand tons lower than in 1993, During the last 27 years, no new alkylation unit has been constructed. As a result of endless discussions of the makeup of processes for an alkylation unit formerly proposed for construction in the city of Ufa [3], plus the lack of investment capital at the present time, a situation has been created in which a butane-butene fraction produced in a modern cat cracker in amounts greater than 100 thousand tons/yr is being underutilized. The construction of a new alkylation unit in this district has been put back to 1999; the existing unit is overloaded. The first units for the production of methyl ten-butyl ether (MTBE) in domestic refineries, with a capacity of 40 thousand tons/yr, were put into service in 1995 as a section of a G-43-107 cat cracker at the Ufa refinery and as a part of the KT-1 complex at the Omsk refinery. It should be noted that synthetic rubber plants in the cities of Nizhnekamsk, Volzhsk, Tol'yatti, and Chaikovsk were already producing MTBE as a high-octane oxygen-containing component of gasoline. In all of the developed countries, the production of high-octane components of gasoline is at a high level. The world production of alkylate in 1989 was 51 million tons; by the end of the century, it will have increased by a factor of 5 [4]. The MTBE production capacity will increase from 10 million tons in 1991 to 22.6 million tons in 1996. Production of MTBE from cat-cracker isobutene is increasing from 1.9 million tons in 1991 to 5.1 million tons in 1996 [5]. Although gas processing facilities do not have any influence on the depth to which crude oil is processed, modernization of existing capacity and the construction of new capacity are needed in order to increase the output of high-octane addition agents for gasoline and for the commercial production of LPG. Presently unutilized reserves of refinery gas are available. The market for LPG has expanded as a result of its use as automotive fuel. As far back as 1987, a standard for this product was developed, GOST 27578-87. A Russian governmental commission has been established to regulate the utilization of natural and liquefied gas as motor fuel, under the direction of the R. Vyakhirev, Chairman of the Board, Gazprom Russian Joint Stock Company.

REFERENCES l.

2. .

4. 5.

Yu. P. Kopylov, L. I. Vstavskaya, A. M. Mazgarov, et al., Neflekhimiya, 30, No. 3, 361-375 (1990). Yu. P. Kopylov, V. A. Alekseev, and R. A. Khaliullin, in: Improvement of Desulfurization Processesfor Hydrocarbon Feedstocks and Gas Fractionation Processes [in Russian], TsNIITI~neftekhim, Moscow (1980), pp. 52-57. "Construction news," Neff' Gaz Neflekhim. Rubezhom, No. 10, 93 (1991) G. Shapo et al., Neff' Gaz Neflekhim. Rubezhom, No. 7, 106-110 (1993). I. Ya. Larina, l~kspr.-Inform. Pererab. Nefii Neftekhimiya, No. 11, 18-21 (1993).

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