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Show Page 4 The American Gilsonite Co. operation is the first privately-financeplant in the United States to manufacture conventional petroleum products from sources. In addition, the plant includes several unique processing features. It will be the first coking plant to perform the complete coking operation at a single site, for American Gilsonite will both produce and calcine the coke here. It is believed that all other refineries ship their green coke to another point for calcining (the final curing operation),. The plant, one of the larger delayed coking units in the country, will make a product of exceptional purity and one which should have ready markets in metallurgical refining and in specialty carbon fields. The name delayed coker is derived from the fact that the plant is designed to delay the formation of coke until it reaches the coke drums. This is a kind of thermal cracking: I.e., cracking the Gilsonite into its light raw gasoline component, and its heavy coke component. Cracking takes place in the coker furnace and the coke is deposited in the coke drums. The plant will convert Gilsonite mined at Company holdings in eastern Utah into high grade coke, with high octane gasoline as an The gasoline important will be sold locally in western , d non-petroleu- m Colorado. The Gilsonite will be delivered to the refinery in water by means of the pipeline starting at and ending at GilUtah Bonanza, 70-mi- le sonite, Colorado. Before 'the- Gilsonite can be fed to the delayed coking unit, it must be separated from the pipeline water. This is accomplished by injecting a small amount of oil into the pipeline upstream from its discharge point at the refinery. Gilsonite has an affinity for oil which causes the small particles to agglomerate and, since Gilsonite is hydrophobic, it can be - separated from the water by straightforward filtering or centrifuging operations. Fart of the dewatered material is delivered to a stockpile which will be maintained at approximately 20,000 tons as a reserve to be used for plant feed whenever necessary. The balance of the dewatered material which has arrived via the pipeline will be delivered to a melting tank where it will be heated to approximately 450F, well above its melting point, by means of heat supplied from hot recycle oil produced in the delayed coker. ' Other recycle streams in addition to the stream being used to melt the Gilsonite are returned to the process in combination with the melted Gilsonite. The combined feed to the plant, consisting of 7,700 barrels of recycle and 3,850 barrels of melted Gilsonite 11,550 barrels per is pumped into a direct day fired horizontal updraft heater operating at 910F. The output from this heater discharges into a coke drum, Here, the liquid separates from the vapor, coke is formed and precipitates out of the liquid. Coke is continually forming and when the coke reaches a level distance within a from the top of the coke drum, the drum is taken off stream and the outlet from the direct fired heater is switched into a clean drum and the cqking process con. pre-determin- tinues. July 20. 1956 The Western Mineral Surrey, Salt Lake City. Utah In hydraulic decoking, a high pressure stream of water (2,200 psi) cuts the coke out of the coke drums. The high pressure jetting apparatus is suspended from der ricks mounted on top of the coke drums. These are similar to oil derricks and are nearly 200 feet high about the height of a building. The Jets are moved up and down through the coke drums to cut out the coke. The mixture of water and coke flows through the bottom opening into a car containing a crushing mechanism which breaks the larger lumps of coke down into pieces approximately three inches in cross section. These pieces, plus coke fines and water, fall into a sluice and then to a specially designed pump which moves them to a decanting tank. During the coke removing operation, this decanter tank is closed at the bottom and the water and fines overflow into a clarifier. When all the coke is removed from the coke drum, the water is drained from the decanter and the coke is loaded from the bottom of the decanter into a conveyor to coke storage. The fines collecting in the center portion of the clarifier are pumped into the decanter during the draining operation. The water is reused for the next operation. The formation of the coke in 16-sto- ry , the drum consumes part of the output from the heater. The remaining part, consisting of vapors and gas, passes through the drum and into the fractionator. Here various vapors are separated and condensed to form liquids. Some become the recycle streams. One liquid, a gas oil fraction, is withdrawn and charged to a thermal cracking heater furnace. In this heater, the charge is heated to, and held at, a cracking temperature of 985aF. After cracking, both the temperature and pressure are reduced and the vapor-liquimixture reenters the fractionating column where it is separated into gas, gasoline, recycle stock and cracked tar. d g This tar contains fractions which are part of the overall coke production when recycled through the delayed coking section. Therefore, the only products from the, fractionator are gas and gasoline. This yapor mixture of gas and gasoline flows from the fractionator as a product, is condensed andor cooled and flows to a separator where it separates into wet gas and unstabilized gasoline. coke-formin- top-of-colu- low-pressu- re .. . A portion of the gasoline is densed to supply sufficient returned to the column as retemperaflux for ture control. The- wet gas is compressed, the gasoline is pumped from the separator and these two intermediate products are mixed, cooled and enter the high pressure separator (115 psi) where the gas and unstabilized gasoline are separated. The gas flows to an absorber where a lean absorption oil fraction from the fractionator absorbs fractions. any desired The effluent gas from the. absorber flows to the plant gas fuel system. The rich absorption oil flows back to the fractionator where the light fractions are vaporized and recycled to the separating absorption stabilization top-of-colu- - low-boilin- g system. The unstabilized 'gasoline ti is pumped from the separator. Is by heat exchange and then passes into the stabilizer, where hot stabilized gasoline of vapor pressure is produced. This end product flows through heat exchange, is cooled and moves to temporary storage for final processing. The stabilizer overhead vapor is partially con high-pressur- pre-heat- e ed pre-determin- ed . sta- bilizer reflux. The uncondensed., ' gas flows from the reflux drum and is recycled through the light ends recovery system. The catalytic reformer consists' of three separate but re- lated processes and constitutes the most comple operation in the refinery, although standard for the industry. The first section of the reformer generates hydrogen which is pumped into the raw gasoline being supplied from the delayed coker to the second section of the catalytic reformer. The hydrogen combines with the nitrogen compounds in the raw gasoline converting them to amonia which can easily be removed as a gas. from the gasoline. The nitrogen compounds must be removed from the raw gasoline, or they would destroy the. catalyst in the third section of the catalytic reformer. The raw material is converted into finished gasoline in the third section of the catalytic reformer. Here propane and butane are also produced which are returned to the hydrogen generation section to make hydrogen . See COKING FR0CESS Page 6 . |
