Hydrocarbon processing hydrogen sulfide removal

The delayed coking feed stream of residual oils from various upstream processes is first introduced to a fractionating tower where residual lighter materials are drawn off and the heavy ends are condensed. The heavy ends are removed and heated in a furnace to about 900 to 1,000 F and then fed to an insulated vessel called a coke drum where the coke is formed. When the coke drum is filled with product, the feed is switched to an empty parallel drum. Hot vapors from the coke drums, containing cracked lighter hydrocarbon products, hydrogen sulfide, and ammonia, are fed back to the fractionator where they can be treated in the sour gas treatment system or drawn off as intermediate products. 

Most sulfur compounds can be removed from petroleum streams through hydrotreatment processes, where hydrogen sulfide is produced and the corresponding hydrocarbon released. Hydrogen sulfide is then absorbed in a suitable absorbent and recovered as sulfur (Chapter 4). 

Fig. 15.16. Fluid coking (Flexicoking)—Exxon Research and Engineering Co. Includes reactor (1), scrubber (2), heater (3), gasifier (4), coke fines removal (5), and hydrogen sulfide removal (6). (Hydrocarbon Processing, 69, no. 11, p. 106, Nov. 1990 copyright 1990 by Gulf Publishing Co. and used by permission of the copyright owner.)...

Conversion Processes. Most of the adsorption and absorption processes remove hydrogen sulfide from sour gas streams thus producing both a sweetened product stream and an enriched hydrogen sulfide stream. In addition to the hydrogen sulfide, this latter stream can contain other co-absorbed species, potentially including carbon dioxide, hydrocarbons, and other sulfur compounds. Conversion processes treat the hydrogen sulfide stream to recover the sulfur as a salable product. 

Hiperion A process for removing hydrogen sulfide and organic sulfur compounds from hydrocarbons. Similar to the Takahax process but using a solution of chelated iron and naphthaquinone. The elemental sulfur produced is removed by filtration. Licensed by Ultrasystems, CA. 

Minex A process for removing hydrogen sulfide and carbon dioxide from gases and light hydrocarbon streams in oil refineries. Developed by the Merichem Company, Houston, TX. 

Sepasolv MPE [Methyl isopropyl ester] A variation on the Selexol process, using the methyl isopropyl ethers of polyethylene glycol as the solvent. Developed by BASF. Four commercial plants were operating in 1985, removing hydrogen sulfide from natural gas. Wolfer, W., Hydrocarbon Process., 1982,61(11), 193. 

Thiolex A process for removing hydrogen sulfide from a light hydrocarbon liquid by extraction with aqueous sodium hydroxide passed through a bundle of hollow fibers immersed in it. Developed by the Merichem Company, Houston, TX. In 1991, 52 units were operating. Variations are known as Thiolex/Regen and Thiolex/Regen/Mericat. See also Mericat. 

Since the Claus process by itself removes only about 90% of the hydrogen sulfide in the gas stream, the Beavon process (Speight, 1993, p. 268), SCOT (Shell Claus Off-Gas Treating) process (Speight, 1993, p. 316 Hydrocarbon Processing,... 

Figure 6 Hydrotreating process. Hydrogen reacts with hydrocarbon feed to remove sulfur from the stream. The formed hydrogen sulfide is steam-stripped from the product. (From Ref. 2.)...

---