TECHNOLOGY o
RGANIC
CHEMICALS
have
always
been derived from carbonaceous fuels. This may seem like another w a y of saying that raw products for organic chemicals are combustible. But the relationship is not casual. Technologies of manufacture of organic chemicals { m o s t ^ c h e m i c a l s ** from^pegejtetaonJ JWMK and fuels have always been and will ^ ^ e j ^ t h o s e \fromJJfopcl y p r p d u ^ l o n ^ b f ^ continue intertwined. The reason is fefproducts -offering " unique^cKemicalj of that most tonnage chemicals are byL^portuniHes^^l . \ W & ! ^ ^ * ^ products of tonnage fuel preparation. Conspicuous exceptions have been ferf f^-2M C h e m i c a l s ^ f r o m ^ d r y ^ n a t u r a l ^ g a mentation processes. .will contract" rather t h a n e x p a n d . * ^ ^ The first coke ovens in the U. S. were operated primarily for chemicals. > t C^?^ Synthetic^gas w i l l ^ b e t l a r g e l y ^ b ^ Later chemicals became by-products .^prp^^ formed during pyrolysis carried out 2? c o n t e n t >Jt w i l l b e tsuita6le|^bnly?"forL V | l o c a l - u s e . E x c e p t i o n isjjgas>feom^iow|> primarily for making charcoal or coke. As demands increased for specific r^temperatareF^^ \>:which c o u l d c b e ^ 6 r a n s V 6 r t ^ ^ e c o n b i m ^ chemicals, ways were found to increase yields and control varieties of products. Processes of pyrolysis came to have l!^V4;/Fischer-Trbpsch Kcbnversibii^fJbfJ dual aims or were again directed priK c p a l V w i l l b e g i n f tb>« s u p p l y * ^ b e f o r e J marily toward chemical production. ^ v l 9 7 0 ) substalntial^a^mountejirf ethykfne%j Processes of synthesis were devised to r Tiahd p t h e r l a l i p h a t i c s , . buC'production f6f} give flexibility and scope to chemicals ImotofJvfuelJtby -, this* : prfeess ^will^be, manufacture. But fuels continue as raw minor. * products for organic chemicals. Petrochemicals on a substantial scale came relatively late upon the scene p^ch^icalsji-wi^ when processes of synthesis were well advanced. Pyrolysis (and incomplete combustion) of petroleum hydrocarttg~ 6.£,Coal* Kydrogenation5wjII Tnoti/pro^ bons leads to formation of materials, I f v i d e ^ s u b s t a n t i a l f a m o u n t s ;^6f - IiPG^'asI such as unsaturates and carbon monr starting - p o i n t JFof aliphatics. } - \ oxide, convenient starting points for chemicals manufacture. Abundant and 7. A r o m a t i c s production- ftom petrpV cheap, petroleum hydrocarbons are imAJ l e u m w i l l t (decline, portant sources of chemicals. / ^ 8 . G a s * f f o m ^ l o w ; . temperature c a r r . Chemical consumption is so low bonization::of /coallmay^^beXabundant* compared with fuel consumption that r^aiid t r a n s p o r t a b l e i b y J p i p e l i n e ; : c but it might seem unnecessary to consider *^' 5 ! wiU j no¥be^as%bpd-a^ourc» of chemi-;| availability and cost of combustibles ideals* as ^petroleum'refinery, g a s . / ' {f*%&\ as raw products for chemicals. The >;, ^ 9 : ? T a f ;frdni - ;lowJ'temperatureJycar^|: cheapest raw products for chemicals > b o n i z a t i o n < o t * { c b a l s h o u l d ; p r o v i d e d are usually by-products of fuel conver%i rcheap a n d a b u n d a n t tar acids; P ^ S t sion processes rather than primary fuels. Abundance and costs of byi l :10. O i l 'shale'Twill ^not , b e * v i m p o r t a n t products are somewhat related to abundance and costs of primary fuels. 9 as a b y - p r o d u c t s o u r c e of p r e s e n t ^ b n i n a g e organics, ^ b u t * -may ^become j i n i ^ Continued acceleration of rate of portant i n fields not^yett d e v e l o p e d ; i 2 growth of the petrochemical industry will ultimately depend upon relative .;A 11., E t h a n e \ f r o n i ^ n a t u r a l ^ g a s r n a n u | abundance and nature of fuel preparaf a c t u r e w i l l b e c o m e increasingly^im? tion processes. Selection of alternative p p r t a n t , for p e b p c h e n i i c a l s X ^ ^ ' l ^ H ' ^ methods of synthesis must b e con*^7 12. JLPG w i l i f c o n t i n u e ^ t o } b e f avail-3 . a b l e , at^least^'untn'^TO^gin^sifficienA^ trolled, in part at least, by competitive , q u a n t i t y f petroleum products. He has recently devoted considerable study to production, use, and economic aspects of national and international fuel resources. H e promoted the first American manufacture of many chemicals, including diphenylamine, lanolin, and synthetic alcohols from petroleum. The present method of large scale chlorination of petroleum hydrocarbons is another of his many contributions to the chemical industry.
V O L U M E
3 2,
NO.
29
JULY
19,
1954
hydrogenation is the production of a b normally large proportions of liquefied petroleum gas ( L P G ) . If an a p p r e ciable proportion of liquid fuel w e r e prepared by coal hydrogenation, t h e present LPG problem of over-abundance would be seriously intensified. But such fears of surplus on the p a r t of the fuel industry and hopes of a b u n d ance on the part of the chemical i n d u s try are not at all likely to materialize because of the improbability of industrial utilization of coal hydrogenation for fuel manufacture on a large scale. Low Temperature Carbonization Offers Superior Thermal Yield
T h e low temperature carbonization, process may well b e the most important of all coal-conversion processes b e cause of its superior thermal yield a n d cost, and the rapid increase of demand, in the U . S. for electric power. C h a r from low temperature carbonization is an acceptable boiler fuel for p r o duction of steam electric power generation. But whatever form the process might take, heat, requirements a r e likely to be such that considerable product-gas will b e available for c h e m i cals manufacture. Its suitability for chemicals will, of course, depend u p o n its composition. From conventional low temperature carbonization the gas contains a lower concentration of olefins than gas from cracking of petroleum. If the process were carried out in the presence of hydrogen (to raise liquid yields) t h e olefin content would not b e improved. W e must assume that gas from l o w temperature carbonization of coal will not be able to compete with petroleum refinery gas as a source of ethylene a n d other olefins. It may b e useful b e cause of its abundance if other b e t t e r sources should b e in short supply. Gas from low temperature carbonization of coal usually contains h y d r o g e n and carbon monoxide in favorable ratio for synthesis. T h e latter may run a s high as 7% of the gas. Future technology may point t h e way toward utilization of such dilute mixtures for c h e m i cal synthesis. The most natural source of certain tar acids would be low temperature tar. If low temperature carbonization should b e practiced on a large scale, it would be necessary to "plow u n d e r " such acids by conversion to liquid fuel. Destructive hydrogenation of low temperature tar to make liquid fuel would give rise to formation of gas somewhat comparable with that from petroleum cracking—competitive for chemicals—but the volume would b e relatively low. 2879
TECHNOLOGY
PRODUCTION OF L.P.G. FROM NATURAL AND REFINERY GASES
ESS SiSIP
pm
wm ^-300
H
mm
mm
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Ell
Figure 2 Shale Oil Can Be Processed For Fuels or Chemicals
Processing of oil shale is similar to processing of coal in t h a t yields a n d kinds of chemical intermediates d e p e n d on the objective of processing—whether for fuels or for chemicals. Oil shale can be processed (high temperature gas entrainment) to make a b u n d a n t ethylene, other olefins, and aromatics, but when t h e primary objective is balanced production of economical liquid fuels, t h e gas will b e low in olefins and frequently diluted with carbon dioxide and air. In other words, most of t h e gas produced as a b y product of oil-shale fuel manufacture will be less desirable for chemicals than gas from petroleum cracking or from low temperature carbonization of coal, and m o r e of it will b e used to supply heat for processing. O n e or t w o oil shale processing plants may b e built for the specific purpose of supplementing, at slightly higher cost, by-product production of chemical intermediates plus manufacture of intermediates from conventional fuel by-products. LPG Production D e r i v e d From Refinery Gas
Largely
T h e petroleum refining and natural gas industries have been contending 2880
for some time with growing ratios of L P G to motor fuel and to dry gas. This circumstance has grown largely out of m o r e widespread application of more efficient processes for liquid recovery. F i g u r e 2 shows the trend with R. C. Alden's projection for 1960 and my tentative extrapolation to 1970. This is of interest because of the usefulness of L P G constituents as starting points for chemical manufacture and as chargi n g stock t o pyrolysis for production of concentrated olefins. More than half t h e ethylene currently produced is m a d e in this way, and extension of ethylene manufacture depends to a considerable extent upon this growing supply of low cost raw product. Most of present L P G production is derived from refinery gas. Some of it is incidental to separation of gasoline from natural gas. Based on our total p r o v e d reserve of natural gas, our total potential reserve of natural L P G should b e around 8 billion barrels. Based on o u r proved oil reserves, our total p o tential reserve of manufactured L P G should be about 3 billion barrels. T h e s u m of t h e two—11 billion barrels—is e n o u g h t o make substantial amounts of chemicals over t h e next century. But the problem is not simple. T h e only L P G now recovered is t h a t for which use has been developed. This C H E M I C A L
amounts to a minor part of that p o tentially available. Some L P G is recovered because it is definitely required. A n example is normal b u t a n e used as an almost essential constituent ( 6 % ) of motor fuel. On the other h a n d , some L P G is recovered from natural gas to make the gas suitable for pipeline transportation. In the first case b u t a n e would b e used in motor fuel even if its cost of recovery w e r e m u c h higher. In t h e second case L P G ( a n d natural gasoline) would b e removed from pipeline gas even if it h a d no more than gaseous fuel value. T h u s , the value of L P G is related to markets r a t h e r than to cost of recovery. T h e L P G not recovered for use is largely b u r n e d as gaseous fuel—in refineries, in flares, a n d as a minor constituent of natural gas. Increasing amounts are being p u m p e d back into the earth with the idea of possible recovery later on w h e n market d e m a n d is greater. In modern recovery of natural gasoline and L P G from natural gas, some ethane-rich streams are encountered. E t h a n e canot b e used as liquid fuel b u t it is a suitable charging stock for pyrolysis t o make ethylene. T h e basic fuel value of e t h a n e is determined b y the value of natural gas it can replace. I n the long run, ethane should b e cheaper than propane or butanes as raw p r o d uct for ethylene manufacture. Refining of P e t r o l e u m Supplies 2 5 % of Ethylene Production
Only about a quarter of the ethylene now being manufactured comes from refinery gas. And yet only about a fifth of t h e ethylene in U. S. production of refinery gas is now being recovered for chemicals manufacture. T h e reason is economic. Unless ethylene is present in very large volumes of gas in sufficiently high concentration and without the complication of some minor contaminants, it may cost more to separate it than to manufacture ethylene b y pyrolysis of ethane, propane, or b u t a n e . This is only because these saturated hydrocarbons can sometimes b e obtained at low cost—ethane as a by-product of ethylene fractionation or as a by-product of separation of natural gas liquids from natural gas, a n d the other hydrocarbons in the form of L P G . E t h a n e as a fuel has only the value of dry natural gas which it can replace, a n d the value of L P G depends on t h e markets that h a v e been developed for this volatile liquid. Refinery capacity will probably increase a t about t h e same rate as d o mestic crude production plus crude imports. T h e sum of the two should cont i n u e to increase at about the present A N D
ENGINEERING
NEWS
WATER-SOLUBLE AMINE PRODUCTS WORTH TRYING
ΑΝΤΙ-STRIPPING AGENT—Hercules RADA added to cut-back asphalts improves adhesion to wet siliceous aggregate and helps prevent subsequent stripping by water.
4f§^k Many new opportunities for product imKL provements are offered by Hercules' group / I of water-soluble rosin amine derivatives. Most important of these is RAD A (Rosin Amine D Acetate), a water-soluble acetate salt. Dispersible in hydrocarbons and alcohol, RADA is a cationic surface active agent that adsorbs strongly on cellulosic and siliceous materials. Readily available in either solution or paste form, this acetic acid salt of Hercules' Rosin Amine D suggests a wide scope of applications.
WETTING AGENT—As an aid in textile processing, the watersoluble amine products have shown their usefulness as wetting agents.
The water-soluble Polyrad® group, ethylene oxide members of the Hercules' rosin amine family, has also indicated its usefulness in various products. Collectively, RADA and the water-soluble Polyrad chemicals exhibit properties of value in bacteri cides, fungicides, corrosion inhibitors, as well as anti-stripping agents for cutback asphalt, wet ting agents in textile processing, flotation agents, and emulsifiers—to mention just a few. To learn more about the versatile Rosin Amine D family, write us for further information on the oil-soluble, water-soluble, and acid-soluble types. Naval Stores Department
HERCULES 982
POWDER
WATER TREATMENT—Several amine derivatives are useful in control of bacteria and fungi in cooling towers and in sec ondary recovery operations.
COMPANY
Market Street, Wilmington 99, Delaivare
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VOLUME
3 2, N O .
29»
·
» .JULY
19,
1954
FLOTATION AGENT—Rosin Amine D Acetate has been suc cessfully employed i n the flotation treatment of certain ores and minerals.
S881
TECHNOLOGY rate, at least until 1960, but should eventually begin to taper off. As soon as it becomes apparent that the peak of petroleum availability is imminent, investments i n refinery additions will be made with a different set of circumstances in mind. Here are a few of them: 1. Refineries will turn more and more to conversion of domestic and imported residual oils to distillate fuels. This will involve some form of hydrogénation. T h e gas produced will not be a good source of ethylene. 2. Conversion of shale oil and coal tar will involve equipment similar to that for conversion of residual, and will not provide a good source of ethylene. 3 . Much is being done by automotive research to make very high octane fuels less necessary for efficient operation of automotive engines. The successful outcome of this work will be particularly important after 1960 because refinery losses are proportional to some function of octane number. But ethylene production also is proportional to some function of octane number. If less emphasis should eventually be placed on heavy cracking, ethylene will be somewhat less abundant per barrel of motor fuel. 4. The ratio of distillate fuel to gasoline is rising. Relatively less of the dis-
tillate fuel will be cracked. So the prospects are for somewhat less ethylene per barrel of crude. 5. The trend has been toward replacement of groups of smaller cracking units with single large units. The trend should continue beyond the present period of abundance of cheap charge-stock because minimal operating costs will b e even more important then than now. By providing large volumes of gas of reasonably uniform composition, the installation of large units should improve opportunities for ethylene recovery. Cracking Refinery Gas Ethane for Ethylene
6. Better methods of recovering ethylene are being developed. T h e economic threshold of profitability will undoubtedly move toward somewhat lower ethylene concentration. This should increase ethylene recovery from refinery gas. From such considerations it may be inferred that while ethylene recovery from refinery gas should some day become lower per barrel of liquid fuel, it should not change very much, one way or the other, per barrel of petroleum. Improvements in recovery may about off-set the effects of lower average tem-
Figure 3
mmMmmmmm t6
illtonsspf/pounds;
ESTIMATED TOTAL ETHYLENE REQUIREMENTS . >
m 54:
m m
PRODUCTION OF ETHYLENE BY SEPARATION FROM REFINERY GAS
m Π.940.· 2882
!
1?5G;
fêjM CHEMICAL
peratures of pyrolysis (higher thermal yields in refining of petroleum). Present recovery of ethylene from refinery gas in the U. S. (not including ethylene increments from pyrolysis of ethane and other refinery gas constituents) amounts to about 0.06 lb. per barrel of domestic crude production plus crude imports. Figure 3 assumes that this factor remains constant, and is based on estimated production curves presented in 1953 before the second American Power Conference. Estimated total ethylene requirements are also shown to indicate the way in which we shall have to depend more and more on sources other than refinery gas and on conversion of refinery gas constituents. Larger proportions of the ethylene component of refinery gas could b e segregated but probably at uncompetitive cost. In Figure 3 consumption of ethylene in 1950 and earlier is a matter of record. Consumption in 1962 was estimated by W . E. Kuhn and J. W . Hutcheson of the Texas Co. b y adding up expected ethylene requirements for ethylene-derived cher ?als. I have simply drawn a straight line between 1950 and 1962 and have extended the line to 1970. Present production of ethylene by cracking of refinery gas ethane is minor but increasing amounts can be expected from this source as ethylene fractionation operations increase in unit size. The practical limit may be about the same order of magnitude as production of ethylene b y fractionation, but t o the extent that refinery gas is used as a chemical raw product instead of as a refinery fuel it must b e replaced b y another fuel—usually natural gas. The value of refinery gas components will reflect the rising value of natural gas. I have gone into some detail about ethylene because it is not only the most important present derivative of refinery gas but also rather typical of aliphatic chemical intermediates. But about a third of all our aromatic production now comes from petroleum. I believe the only justification of benzene production from petroleum is that expansion of market demand has preceded commercial development of coal hydrogénation for chemicals. Because of relatively low yields and high costs I would expect petroleum benzene to b e a limited development that will become unimportant when coal-benzene is n o longer merely a by-product of steel manufacture. T h e same principle should apply, though in lesser degree, to petroleum toluene, which, however, should have a longer life because yields are relatively good. AND
ENGINEERING
NEWS
