•
PRODUCTION TAIL GAS TO FUEL
BY-PRODUCT HYOROGEN KeS TO SULFUR RECOVERY
RECYCLE COMPRESSORS
TAIL GAS TO VAPOR RECOVERY , AMINE WASH SYSTEM ATMOS. FRACTIONATOR HEATING OIL·
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VACUUM FRACTIONATOR
FLUXED ASPHALT FEED
Y W
Y TO FUEL OIL
ASPHALT HYDROGENATION UNIT
Humble Oil's n e w asphalt hydrogénation process uses cobalt molybdate-onalumina catalyst at 725° to 825° F. and 400 to 800 p.s.i.g., giving 2 0 to 7 0 % conversion of the asphalt feed into distillate fuel products
Cat Cracker Feed Stocks Humble researchers develop a commercially feasible process to upgrade asphalt residues with hydrogen
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More an d more, oil companies are scraping the bottom of the barrel to boost crud e yields. In effect, they're milking the refinery for all the cat cracker feed stocks they can get. Some have turned to thermal cracking, or coking, of vacuum crude residua. Others remove -asphalt from the residua with light hydrocarbon solvents, blend the asphalt with bunker fuel, and feed the deasphalted oil into their cat crackers. And more recently, Humble has developed a method of asphalt hydrogénation which upgrades this fraction into gasoline, light heating oil, and gas oil. "We have obtained conversions of 20 to 7 0 % in our Baytown pilot plant/* says R. L. Heinrich, "and the process looks commercially feasible." In a report last week to the I>ivision of Petroleum Chemistry, Heinrich said the Humble process uses a cobalt 4686
C&EN
SEPT.
24.
1956
molybdate catalyst at pressures of 400 to 8 0 0 p.s.i.g. Catalyst life and activity are good; the operation produces high, quality distillate products. Desulfurization, b e noted, accompanies asphalt conversion. A low-pressure hydrodesulfurizationhydroconversion process, according to Heinrich, has certain advantages over conventional processes for residuum conversion: • It produces stable products o f superior quality, low in sulfur content, with much higher yields of the more useful and valuable distillate products. • Produced in l o w yields, t h e residual fraction after mild hydrogénation is suitable for blending into bunker fuel oil. • Two-Way Advantage. "The return o n investment is most attractive when hydrogénation is carried to a ?QT>Vf*?*a-*
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rich. And this can b e accomplished under severe process conditions or by
the optional use of product recycle. But the 1000° F.-and-heavier bottoms product isn't acceptable for blending into a merchantable fuel oil. Oil companies, however, can burn this fraction for their own fuel needs around the refinery. You can go t h e other way, Heinrich indicated, and g e t a good bottoms product, with only a moderate conversion of 2 5 to 4 5 % . Mild hydrogénation shows a lesser, although reasonably attractive, monetary return. Most refiners will probably b e interested in the operation that produces a saleable fuel oil. Baytown researchers, Heinrich says, h a v e calculated an overall product credit of about 50 to 8 0 cents per barrel of asphalt feed, for certain o p erating conditions. And some refiners could get additional credits from conversion of by-product hydrogen sulfide into sulfur. As to processing conditions, Heinrich made certain important disclosures: • Hydrogénation is carried out at 7 2 5 ° to 825° F . , at total pressures of 4 0 0 to 8 0 0 p.s.i.g. • Feed rates vary from 0.5 to 2 volumes of liquid feed per hour per volume of catalyst. • The process requires 1500 to 4 5 0 0 standard cubic feet of hydrogen per barrel of feed. • Under properly selected conditions, t h e cobalt molybdate-on-alumina catalyst may b e used continuously without air regeneration for more than 5 0 0 hours—at conversion levels up to 6 0 % by volume of feed. • Hydrogen consumption which varies with the conversion level, is normally between 300 and 1000 standard cubic feet per barrel of feed. • General
Purpose
Pilot
Plant.
"The asphalt experiments were carried out in our general purpose hydrogénation pilot plant," said R. S. Manne of Humble Oil & Refining, in a related paper. This unit, h e explained, will process 0.5 to 3 barrels of oil per day. It is equipped to operate either with once-through or recycle gas—the gas c a n be commercial cylinder hydrogen or tail gas from a plant catalytic reformer. The product recovery section h a s a continuous vacuum flash tower (operating at controlled absolute pressures as low a s 2 mm. of mercury) so that researchers can recycle residuum w i t h a boiling point in excess of 1040° F. Humble's pilot plant, designed with emphasis on flexibility, will run 0.5 to 4 volumes of oil per hour per volume of catalyst, at pressures up to 8 0 0 p.s.i.g. and temperatures up to 850° F. Reoyole gas rates ,can b e varied from 0 to 6 0 0 0 standard cubic feet per barrel of oil charged. Approximately 1.25
chlorine caustic L soda
sulphuric acid
ammonia
soda ash
y o u c a n be o n our "pipe line' 9 Want t o smooth, out your chemical supply problems? T a p into the Olin Mathieson "pipe lines/* You'll see what our multi-plant production facilities can mean t o you. The effect of a number of producing points is to balance out local shortages and surpluses. In. one instance, a serious chlorine shortage on the Gulf of Mexico was relieved b y an excess in Canada. Each of the frve plants between shipped into the next plant supply area to the South, setting up a chain reaction which released the needed tonnage on the Gulf. Our combination of multi-plant facuities and an imaginative approach to the logistics of the chiemical industry can prove invaluable to you. Discuss it now with an Olin Mathieson representative or write the Chemicals Executive Office in Baltimore.
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MATHIESON O L I N
M A T H I E S O N
CHEMICALS
C H E M I C A L
INDUSTRIAL CHEMICALS
DIVISION
C O R P O R A T I O N ·
BALTIMORE
3, M D .
MATHIESON
4Î2H
INORGANIC CHEMICALS: Ammonia · Bicarbonate of Soda · Carbon Dioxide · Caustic Potash · Caustic Soda · Chlorine · Hydrazine and Derivatives · Hypochlorite Products · Muriatic Acid - Nitrate of Soda • Nitric Acid · Soda Âsh · Sodium Chlorite Products · Sulphate of Àiumina · Suiphur ^Processed) · Suipiiufic Aciu ORGANIC CHEMICALS: Ethylene Oxide - Ethylene Glycols · Polyethylene Glycols · Glycol Ether Solvents · Ethylene Dichloride · Dichloroethylether · Formaldehyde Methanol · Sodium Methylate · Hexamine · Ethylene Diamine · Polyamines · Ethanolamines · Trichlorobenzene · Polychlorobenzene · Trichlorophenol
SEPT.
2 4,
1956
C&EN
4687
PRODUCTION gallons of catalyst constitutes a charge to the 2-inch by 8-foot reactor. The oil preheat system is designed to allow considerable variation in holding time under almost any desired temperature pattern, permitting researchers to study thermal or catalytic processes. Various combination processes, such a mild catalytic hydrogénation with severe thermal preheat, can he carried out. The pilot plant has facilities for regenerating the catalyst in place and for determining the amount of carbon and sulfur removed from the catalyst. Humble's pilot plant, says Manne, will take anything from a light West Texas gas oil having a gravity of 35° API to a fluxed asphalt of 7.2° API gravity. • Fast Data Processing. Each yield period o n the pilot plant (normally 12 or 24 hours) is run through a complete, detailed material balance and component balance calculation. To minimize personnel requirements, the entire work-up has been programmed for IBM Type 650 computing equipment available in Humble's Accounting Department. All orifice meter and rotameter calibrations are programmed, as are temperature corrections for gravity and for gas saturation. Conversion factors, allowing for different units of various measurements, are included. Operators need only to record raw pilot plant readings onto forms for key punching. The calculation is divided into two parts: • A yield, material balance, and process conditions computation requiring only data which are immediately available. • A hydrogen balance, sulfur balance, a balance for each light hydrocarbon component of the gas streams, and yield data on various liquid fractions. To direct changes in operation, the first part can b e completed, if necessary, and made available to plant operators within an hour after completion of a run. The second part, dependent on gas analyses and distillation data, comes through later, pending completion of these tests. By programming options into the machine computation, it is possible to handle runs uniformly, regardless of how the pilot plant is operated, including a switch in orifice plates, changes in feed stocks, and the use of impure hydrogen as make-up. Each alternative requires changes in computation procedure, but these ~1
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use of the "logic" features of computer. 4688
C&EN
SEPT. 2 4,
the
1956
Reducing Caking Tendency Armour's fatty amine formulation keeps some gran ulated fertilizers free-flowing in pilot plant tests Caking during storage has tra ditionally been a most troubiesoioe and annoying pro clivity of chemical fertilizer. So hard can a fertilizer become that farmers often refer to an 80-lb. bag of caked fertilizer as a "tombstone," which they must break up with a sledge hammer to transfer its contents into the spreader. Even then, remaining agglomerates clog the spreader, pre venting even application as well as causing lost time during hectic spring planting. But to the fertilizer industry, caking has caused economic problems as well. During curing, a pile of fertilizer m a y become so hard that blasting is re quired before it can be bagged. It also prevents the industry from storing its products indefinitely and from realizing the advantages of conventional bulk handling equipment such as is used b y the grain industry. Many solutions to this problem have been tried—some with considerable suc cess. Perhaps the most far reaching has been the recent trend toward granu lating fertilizers. Granulation concen trates fertilizer into small particles of nearly uniform size ranging in diameter from 1 to 4 mm. With mixed goods, granulation prevents segregation cf compounds and reduces their tendency to cake or become sticky. The extent to which this process has spread in recent years was shown in a paper Walter Scholl of USDA presented before the Fertilizer and Soil Division of the ACS in Atlantic City. H e said that about 9% of the mixed ferrilizier sold in the U. S. during the year ending June 30, 1955, was in granulated form. The North Central region took about 37% of its mixed goods in granules. Farmers have shown willingness to pay a slight premium for a free-flowing product. However, granulation does not al ways produce an entirely free-flowing product. In the higher analysis prod ucts such as 12-12-12 (that is, 12% nitrogen, 12% phosphate, ano\ 12% potash), the ideal of a free-flowing fertilizer is still out of reach even with granulation. Its hygroscopic salts a b sorb moisture from the air, producing a set in the bag. To make it more freeflowing, mineral dusts have been used
ID
Granulated fertilizer coated with RD2461-F (left) is free-flowing versus uncoated, caked granules (right) to coat the pellet surface, but the 10 to 20 pounds of such materials needed per ton of fertilizer for effectiveness re duces the plant food content. Addi tional drying can do the job but it in creases capital investment if more equipment needs to be purchased or it reduces plant capacity if recycling through present equipment is used. It also means increased fuel costs. Armour Chemical Division now comes up with a formulation of a fatty amine, a solvent, and a spreading agent, which it says can do the job for 0.25 to 0.5 cents per 80-lb. bag of fertilizer. The fatty amines Armour workers find best contain 16 to 18 car bons per molecule. Mixtures of these compounds can also be used. An nouncing this product and discussing the research behind it in Atlantic City r Robert E . Baarson of Armour showed how in laboratory and pilot plant tests 0.1 lb. of this formulation per ton of 12-12-12 fertilizer increased the per centage of free-flowing material from 50% to 100%. The solvent, h e told C&KN, is a hydrocarbon, and the spreading agent is cationic. The fatty amine, h e said, coats the fertilizer granule with a hydrophobic layer, which either cuts down or elimi nates water absorption. H e believes that the amine group attaches directly to the granule, foraaing an amine phosphate and orienting t h e fatty, hy drophobic group outward. At levels higher than 0.5 lb. of formulation per ton, the percentage of free-flowing fertilizer will first decrease and then, upon addition of even more, increase again This, Baarson speculates, is due to formation of multiple layers, with the even numbered layers orienting
