Chemistry and Technology of Fuels and Oils, Vol. 30, Nos. 7-8, 1994

SELECTION OF RAW MATERIAL FOR BASIC ORGANIC SYNTHESIS O. P. Lykov

UDC 665.71(075.8) + 665.612.004.14 + 622.276

The most important conditions for growth in processes of basic 0aeavy) organic synthesis (HOS) are a suitable supply of raw material and its proper utilization. The type and quality of raw material determine to a great degree not only the technology but also the economic and ecological parameters of these processes, as well as the product quality. In the petrochemical industry, feedstock costs average about 70%. The norms established for the consumption of raw material per unit of end-product are very high. In the production of synthetic rubbers and polyethylene, for example, the raw material consumption is 3 tonnes/tonne, and for nylon-6 the consumption is 7.4 tonnes/tonne. In the cost structure for HOS products, raw material accounts for 60-70%, fuel and energy 10%, labor costs 5 %, amortization deductions 3-4 %, and other costs 1223%. In the light of the foregoing discussion, it can be seen that the selection of a raw material base is extremely critical in terms of long-term future growth of HOS, particularly since a period of 10-15 years may elapse between the time the first laboratory results are obtained and the actual date of completion of plant construction and the initial output of product. What are the potential sources of organic raw material that are available for HOS processes in the world and in Russia in particular? There are only four such sources: crude oil, including gas condensate; natural and associated petroleum gases; coal and oil shales; and plant biomass. What sort of criteria should be imposed on the selection of raw material with a view to satisfying not only current demands but also long-term future demands? Obviously, the basic criteria are the resources of the particular type of raw material (so as to ensure reliable output of HOS products) and the cost of the raw material. Other factors that must be taken into account are the world trends in evolution of the raw material base and evolution of existing technologies, the quantities and variety of HOS products, and ecological problems. The selection of raw material for HOS must be based on a systems approach so as to obtain a coordinated solution of an entire group of tasks. We are well justified in rejecting certain obsolete predictions of a number of scientists to the effect that the next 50-100 years will witness the exhaustion of nearly all of the known resources of oil and gas and that the worldwide economic growth will come to a halt in the next few decades. According to modern views, the world production of mineral raw materials, in the long term, will not be limited by natural resources. The supply situation on the most important types of organic raw materials (oil, gas, and coal) is considerably better today than in the years immediately after the second world war. Thanks to technological improvements and measures to conserve energy and materials, including the use of secondary material resources, a trend has been noted toward a relative decrease (and in some countries an absolute decrease) of the consumption of organic mineral raw materials. However, from the standpoint of the more distant future prospects, resources (including potential resources) of the so-called nonrenewable sources -- oil, gas, and coal -- will not only be limited, but will also differ greatly in terms of volumes. Therefore, any determination of the production volumes for these raw materials should consider the demand of future generations, from the standpoint of not only economic and social considerations, but also likes and dislikes. The prices for mineral raw materials are a primary concern of the countries importing a given type of raw material, and also the exporting countries, at least up to the time when exhaustion of the deposits is threatened. However, prices for mineral raw materials and energy resources on the world market change so rapidly that any long-term predictions are highly questionable. A rather reliable reference point for cost and price projections may be found in the theory of rent for mineral production and the costing and pricing of organic fossil fuels based, on the one hand, on the expenses involved in mineral I. M. Gubkin State Academy of Oil and Gas (GANG). Translated from Khimiya i Tekhnologiya Topliv i Masel, Nos. 7-8, pp. 7-12, July-August, 1994. 302

0009-3092/94/0708-0302512.50 9

Plenum Publishing Corporation

TABLE 1 V t

Consumption of gas Year 1985 1990 1995 20oo

% of total billion m3 volumeof consumption 522 607 688 755

29,7 29,2 29,6 29,7

~,. Naturat gas

synthesis gas

Processing of | " synthesisgas ]

[ methanol

Processingof methartol

Plasmopyrolysis

i

Processing of acety- I lone-containing gas l

!

f k

i

Chemicalproducts: olefins, alcohols, glycols, a r o ~ hydrocarbons, acids, anhydrides,etc.

J

Fig. 1. Scheme for processing dry natural gas into HOS products production from the poorest deposits and the profitability and, on the other hand, on the costs for iarge-scale production of alternative materials or energy. In view of the growth trend in the world economy, it must be recognized that the era of inexpensive organic mineral raw materials (oil, gas, coal) is rapidly fading into the past. The demands of HOS for raw materials depend primarily on the type of raw material (as will be shown below), and. also on the results of scientific and engineering progress. Only a careful selection among newly created technologies, plus support for material and energy economic production, wilt make it possible to adapt gradually to new conditions of raw material pricing. In long-term predictions of the demands of society for specific types of products of organic synthesis, serious difficulties are encountered, particularly in Russia. The starting point should probably be the assumption of steady growth of demand for the particular product during the course of an extended period. Quite likely there is no universal solution of this problem that is valid for differetlt countries and regions of the world. Today, crude oil is the basic source of raw material for HOS. The worldwide proved reserves of crude oil in 1993 were calculated as 137 billion tonnes; the worldwide oil production volume in 1992 was 3 billion tomles, remaining at the 1991 level. According to estimates of the lEA, the worldwide demand for crude oil will increase by about ! % per year [1]. Thus, we can note a worldwide economic trend toward stabilization of the production and consumption of crude oil. In the CIS countries, oil production has dropped by 70 million tonnes each year, with most of this decrease (66 million tonnes) attributed to a decline of production in Russia. However, this fact cannot be taken as evidence of any long-term trend. For exmlaple, in the USA in 1991, oil production declined by 14 million tonnes. In the USSR during the period 1950-1980, the oil production (with gas condensate) increased by a factor of more than 15; at the end of the 1980s, however, production dropped off sharply, amounting to 624 million tonnes in 1988 and only 425 million tormes in 1992 for the same geographical area. The declining trend in Russian oil production is obvious: 517 million tonnes in 1990, 461 in 1991, 390 in 1992, and 338.5 in I993. To all appearances, almost 12% of the oil reserves have been extracted, and it should be expected that within 20-25 years the oil reserves will have been reduced by 30-35 % [2].

303

Natural gas

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~=~

Fig. 2. Scheme for processing natural gas into HOS products. In all recent years, the oil supply on the world market has exceeded the demand. In 1992, the average world price of crude, including delivery to the consumer, dropped by almost $1.00 per barrel (159 liters); the price for Dubai crude, which is similar in quality to Russian crude, was $16.50 per barrel; and the price for high-quality, low-sulfur North Sea crude was $18.00 per barrel. The prices for liquid petroleum products dropped simultaneously. World cooperation is still lacking in regard to crudes of the North, Norwegian, and Barents Seas, and also in a number of difficultly accessible districts where the oil production costs are extremely high. These costs, plus normal profit, represent the lower limit of world oil prices. The upper limit is established by the cost of large-scale, profitable production of synthetic liquid fuel (SLF) from coal and oil shales. Today, the ratio between the upper and lower limits of price is 4.4-2.4. The high values of this upper limit on prices are determined by the large capital investment required to produce SLF. It must be recognized that the era of inexpensive, readily available fuel in Russia has ended, probably forever. The worldwide consumption of crude oil as a raw material for HOS (relative to total production volume) was 6% in 1976, and 10-12% in 1985. The crude oil consumption in HOS is predicted to reach 20% in the year 2000. It will be noted that this trend toward increasing consumption of crude oil for this purpose is quite stable. In the CIS, more than 80% of the total volume of hydrocarbon feedstocks for HOS is obtained from petroleum refineries. The feedstock volume required to meet the needs of petrochemical production is relatively small, amounting to about 5% of the total volume of crude oil processed; however, this volume is made up of the most valuable straight-run naphtha, kerosene, and diesel fuel fractions, as well as LPG, propane-propylene and butane-butylene fractions, and aromatic hydrocarbons [3]. It should also be noted that the energy costs in the petrochemical industry are greater than the raw material costs. On the average, for every tonne of raw material, 1.37 tonnes of equivalent fuel (TEF) are consumed in the form of steam and fuel, and 0.18 TEF in the form of electrical energy. The total petroleum equivalents in the manufacture of the most important petrochemical products are as follows (in tonnes/tonne): styrene 6.8, isoprene 8.5, polyethylene 3.9. Summarizing, let us note that under the conditions existing in Russia, we should strive to minimize the consumption of crude oil as a raw material and energy source in HOS. The quantity of oil allotted for this purpose will depend on the degree 304

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Fig. 3. Scheme for processing associated oilfield gas into HOS products. to which petrochemical production technology is improved and perfected. It is already clear that energy-intensive, !owselectivity processes in petroleum refining and petrochemical production are becoming unprofitable, and they must give way to a new generation of technologies. There is considerable leeway for economizing on petroleum feedstocks in a number of petrochemical processes, as the selectivities of the existing processes are very low - for example, 50 % in the production of synthetic fatty acids, 70% for ethylene oxide, and 80% for phenol by the cumene method. Worldwide and domestic experience shows that the demand for liquid hydrocarbons will inevitably increase in the future, both for the production of motor fuels and for petrochemical production. In view of the declining volumes of oil production and refining in Russia, it should be recognized that any expectation of expanding the raw material resources for HOS through crude oil processing is hardly realistic. Resolution of this problem will require a search for other sources of feedstocks. Coal and oil shale occupy an important place among the alternate sources of feedstocks. Coal-tar chemistry continues to supply various HOS feedstocks: lower olefins from coke-oven gas, aromatic hydrocarbons from coal tar, synthesis gas, acetylene, and other raw materials. Serious efforts are being made in Russia toward the replacement of petroleum by coal as a source of HOS raw materials. The worldwide reserves of coal are considerably greater than the reserves of oil and gas. The coal reserves available for commercial mining are equivalent to 480 billion tonnes of crude oil; the total reserves of oil and gas are equivalent to only 270 billion tonnes. Coal is the most promising organic mineral in Russia. Coal reserves in the former USSR were estimated at approximately 7 trillion tolmes, explored reserves at approximately 300 billion tonnes. At the present rate of coal mining, the explored reserves alone will last for 150-200 years. The production of coal in Russia in 1992 was 328 million tonnes. However, a declining trend has been observed in recent years; the production dropped by 84 million tonnes in 1990-1992, and was expected to drop in 1993 by 40-45 million tonnes. The competitive situation between HOS products based on coal or petroleum depends on the ratio of prices for crude oil and coal. The average European price for 1 tonne of coal is 28-30 dollars. Today and also in the immediate future, processes of coal-tar chemical synthesis are not competitive with petrochemical processes, owing to the extremely large amounts of coal required to obtain basic products (monomers). For example, calculations have shown that in order to obtain 45 million tonnes of ethylene (worldwide average production volume), 1.35 305

TABLE 2

Product

Manufacturing technology

Prorated costs (%) for product manufacture from crude oil { from natural gas

Ethylene Propylene Aromatic hydrocarbons

Pyrolysis Recovery from refinery propane-propylene fraction Propane dehydrogenation Catalytic reforming Aromatization of C3- C5 hydrocarbons

100 100 100 -

1

80-94 86 82

TABLE 3 Hydrogen production method Conversion of plant biomass with water Conversion of carbon (coke) with steam Conversion of natural gas (methane) with steam

. . . .ylela Ii Consumption o f - - ] Process h yurogen tempera- kg/lO0 ' heat per hydrogen kg ture, ~ molecule, kJ / 500-700 15 105,0 1000-1200

17

151,2

600-800

50

63,0

billion tormes of coal would be required - approximately the entire world production of coal (outside the USSR) in the 1980s. The cost of work to realize such a program is estimated at 550 billion dollars. There are two possible paths to be taken in HOS based on carbon monoxide and hydrogen. The first of these is the production of paraffinic hydrocarbons that are then used to synthesize alcohols, nitrogen derivatives, and halogen derivatives. The second path is the direct conversion of synthesis gas or methanol into HOS products. It should be kept in view that SLF production and hydrocarbon production are closely interrelated when they are produced from carbon monoxide and hydrogen, the same as when obtained from petroleum raw materials. The possibilities of synthesizing a broad range of paraffinic hydrocarbons on the basis of synthesis gas obtained from coal are limited primarily by the high cost of this gas and by ecological problems in coal processing, as well as the relatively narrow possibilities of oxosynthesis processes in HOS technology. Advances in the synthesis of hydrocarbons from carbon monoxide and hydrogen may open up new paths in this direction. A similar situation is observed in the production of SLF from coal. In various countries, a second generation of this process technology has appeared. In the USA, Japan, and the FRG, such processes are being worked out in pilot-plant units. Large-scale commercial production of SLF has been set up in South Africa, where it supplies up to 50% of the total fuel consumed. However, any large-scale organization of SLF production from coal has been held back by the relatively low price of crude oil, and also by the need for mining and processing large volumes of coal for this purpose. In the future, therefore, at least up to the year 2000, these technologies will not be widely employed. For the production of only 100 million tonnes of SLF, about 500 million tonnes of coal are required, a quantity that is commensurate with the total production of coal in the USA, for example. The productivity of labor in oil production, even under extreme conditions, is considerably higher than that in coal mining. For the production of 25,000 tonnes/day of crude oil from the North Sea fields in the 1980s, 40-50 man-days were required; for the production of only 5,500 tonnes/day of SLF from coal, 74 man-days were required. The costs for the production of SLF from coal are 3-4 times those for production from natural gas. Moreover, coal mining and particularly coal processing create serious ecological problems, casting doubt on the advisability and feasibility of large-scale chemical processing of coal. Only a substantial reduction of costs for coal gasification in the future could make synthesis gas more readily available for organic syntheses. Rail transport of coal is far more expensive than pipeline transport of oil and gas. Thus, even in the relatively long-term view, coal cannot compete seriously with oil as a raw material for HOS. Here, of course, we cannot dispute the value of coal as a source of energy, particularly in districts of Russia that do not have any 306

developed system of pipeline transport of oil and gas, although even in this field of application the share of coal had dropped to 20% by the early 1990s. Recent years have witnessed a continuous increase in the importance of the role of natural gas as a raw material for HOS. The total world proved reserves of natural gas amounted to 122,315.8 billion m3 in 1990 and 136,145.5 billion m 3 in 1992 [4]; about 38% of these reserves are located on territory of the former USSR. The potential resources of natural gas in the CIS amount to 268 trillion m 3, the largest in the world. Explored reserves of gas account for 54.4 trillion m 3, or about half of the world reserves. Thus, the gas industry has a reliable raw material base. The worldwide volume of natural gas processing and consumption in 1990 was 2080 billion m3. The total extraction of organic fuel in the USSR in 1990 was approximately 1750 million tonnes in crude oil equivalent; natural gas accounted for slightly less than half of the production of primary energy resources. The more than fourfold increase of gas production in the USSR during the last two decades is evidence of stable growth. During all the years of development of gas deposits, about 10 trillion m 3 of gas has been produced, or 4% of the potential reserves. The production of natural gas in Russia in 1992 remained at the 1991 level, 640.4 billion m 3. The explored reserves of gas are adequate to support the present level of production for 60-70 years. Calculations indicate a possible and necessary increase of gas production to 1000-1100 billion m 3 per year at the juncture of the 20th and 21th centuries, with a subsequent increase to 1230 billion m 3. The specific capital investment for gas production is less than one-fourth that for coal production [2]. Therefore, the prospects for long-term, continuously increasing use of natural gas in Russia, including its use as raw material for HOS, are extremely encouraging. In the concepts of the energy policy approved by the Russian government for the next decade, priority is given to natural gas over other sources of energy. However, consideration should be given to file need for mastering ecologically acceptable technologies in the production and transportation of gas. Most of the giant gas fields (on the Yamal Peninsula, in tundra districts, and on she!ves of the Arctic) are far away from the primary centers of consumption; this requires a continuation of the construction of cross-country gas transmission lines, with all of their costly infrastructure, ha high-risk ecological regions, thus demanding major investment and considerable time to open up these deposits. Gas prices on the world market are considerably lower than oil prices. However, the high cost of transportation and distribution of natural gas has a slight but definite adverse effect on its competitiveness with other sources of raw materials. The prospects for competition of natural gas at the interindustry level as a possible raw material for HOS appear to be extremely promising. The fraction of natural gas used in worldwide HOS has remained practically constant during recent years, although the absolute volume has increased steadily (Table 1) [5]. In the USSR, this fraction was considerably lower, although a growth tendency was also noted [6]: 5.4% in 1965, 7.4% in 1975, 7.6% in 1985, and 8.6% in 1990. The total consumption of natural gas as raw material for HOS in Russia amounts to 8 % of the gas production volume. However, this level cannot be considered as adequate. Of the 840 billion m 3 of gas produced in the USSR in 1990, somewhat less than 10 % was subjected to processing, even though according to certain estimates [3], the volume of processed gas, mainly ethane-containing gas, should increase to 150 billion rn3 by the year 2000. The processing of such a quantity of natural gas, together with 75 billion m 3 of associated oilfield gas, 35 million tonnes of gas condensate, and 4 million tonnes of unstabilized naphtha, will make it possible to obtain 6.3 million tonnes of ethane, 8 million tonnes of LPG (C3 - C 4 fraction), and 0.12 million tonnes of isopentane -- products that can be used to obtain very nearly the entire range of petrochemical intermediates and monomers. In Fig. 1 we show a scheme for the possible directions of HOS from dry natural gas [3]. Natural gas with an ethane content greater than 3 % by volume (such as is produced in many fields) is best processed cryogenically to obtain ethane, propane, butane, and isobutane. A scheme for possible directions in processing natural gas that is rich in ethane, propane, and butane (wet gas) into HOS products is shown in Fig. 2. Analogous directions in the processing of associated oilfield gas are shown in Fig. 3. The gas produced from many of the explored fields in Russia contains components that are valuable in terms of further processing: 44.7 % of the reserves contain ethane, 50 % gas condensate, and 15.8 % hydrogen sulfide. Evaluations indicate that almost all of the products obtained from crude oil can be produced from gas; i.e., in practically all large-scale syntheses, feedstocks derived from crude oil can be replaced by gas. Even today, the consumption of natural gas as a raw material for the chemical industry is greater than its consumption in all other directions. By 2000 it will probably increase by 233 billion m 3 in comparison with 1985. Most of the natural gas 307

supplied for chemical processing is used in the production of hydrogen, acetylene, and synthesis gas, with subsequent production of methanol, ammonia, products of oxosynthesis, etc. It is still important to compare the unit costs in HOS production from crude oil-derived hydrocarbons and natural gas. In Table 2 we show prorated costs (%) for large-scale production of petrochemical intermediates [7]. It will be seen that production of the most important HOS monomers from natural gas is more efficient than from products of petroleum refining. Biomass may become another source of raw material for HOS. For the entire planet -- on land and in bodies of water - - 150-200 billion tonnes (dry weight) of biomass are formed annually; approximately the same quantity is decomposed as a result of various oxidative processes. Of the biomass that is formed each year, no more than 10% is utilized by the human race. If we could succeed in utilizing only one-tenth of the biomass that is decomposed in nature, this would be equivalent to 6-8 billion tonnes of crude oil, more than twice the present level of oil production. In terms of energy equivalent, the annual renewability of forests of commercial species is greater than 50 billion tonnes, of which less than 1 billion tonnes are utilized. Apart from biomass, consideration should be given to the use of industrial and domestic wastes. In the USA, for example, wastes from the forest products industry and low-value wood amount to about 110 million totmes of equivalent fuel annually, or 75 million tonnes of crude oil. It is especially important that biomass is a renewable source of raw material, There are numerous examples of large-scale HOS based on biomass. In Brazil, about 7 billion liters of ethanol are produced annually from plant materials. The volume of ethanol production from biomass solely as a high-octane component of motor fuels is estimated at 7-8 million tonnes/yr. From the ethanol obtained in this manner, in units with capacities up to 100,000 tonnes/yr, one of the basic monomers of HOS is obtained, namely ethylene. In Table 3 we have listed the characteristics of certain existing and prospective methods for hydrogen production [8]. It can be seen that hydrogen from renewable sources of raw material (biomass) may become an extremely promising raw material for commercial hydrocarbon synthesis. Synthesis gas obtained from biomass may play a significant role in solving the raw material problem in the commercial production of organic products, particularly methanol and acetic acid. Process technologies for many syntheses based on biomass are quite well known, but the product cost is often an order of magnitude greater than for their "petrochemical analogs," owing to difficulties in biomass harvesting, preparation for processing, and transportation. In the present stage, for example, hydrogen from biomass is best produced in mobile units in the areas in which the biomass is accumulated. In general, it is difficult to organize any large-scale production based on biomass. Moreover, biomass has extremely important ecological functions in nature, and hence the utilization of biomass is the most attractive for countries with large land areas, On the basis of all of the discussion in this article, we can suggest that the HOS raw material base should be expanded by including natural and associated gas. Such a change in orientation of the raw material supply for HOS should stabilize or even reduce the quantity of hydrocarbon feedstocks furnished to petrochemical combines from refineries. Such a conclusion is based on the following constant factors: An increase of demand for HOS products. A significant decline of accessible, low-cost resources and a drop of the actual crude oil production volumes. The existence of huge reserves of gaseous hydrocarbons in our country, with infrastructure either existing or being created for production and distribution of these hydrocarbons. Worldwide developments, either completed or in progress, for commercial chemical processing of natural gas and associated oilfield gas. Such a transition can probably be accomplished in two stages: up to the year 2000, extensive utilization of compressed and liquefied natural gases, ethane, and C 3 - C 4 fractions, as well as methanol, obtained from natural gas; after 2000, manufacture of HOS products directly from methane. Such a transition will require significant capital investment, structural reorganization, and modernization of a major part of the production facilities.

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.

2.

308

Yu. P. Kopylov et al., Neftekhimiya, 30, No. 30, 361 (1990). A. F. Andreev et al., Current Economic Problems of the Oil and Gas Industry [in Russian], GANG ira. Gubkina, Moscow (1992).

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O. B. Braginskii and t~. B. Shlikhter, "Prospects for chemical processing of natural gas and associated oilfield gas," Ser. Neftekhim. Slantsepererab. (TsNIITt~neftekhim, Moscow), No. 6 (1991). Neff' Gaz Neftekhirn. Rubezh., No. 8, 9 (1990). Gas World Int., 195, No. 4853, 6 (1990). L. D. Utkin, "Economic efficiency of improvement of structure in gas consumption," Ser. l~kon. Uprav. Gazovo Promst. (VNIII~gazprom, Moscow) (1987), p. 10. ~ O. B. Braginskii et al., Gazov. Promst., No. 11, 4 (1989). Ya. M. Paushkin, Yu. M. Zhorov, A. L. Lapidus, et al., Dokl. Akad. Nauk SSSR, 298, No. 2, 374 (1988).

309