GB830960A - Improvements in the gasification of hydrocarbon-containing oils - Google Patents

Abstract

<PICT:0830960/III/1> <PICT:0830960/III/2> A gas containing gaseous hydrocarbons is produced by passing a hydrocarbon-containing oil and a hydrogen-containing gas under a pressure of at least 3 atmospheres through a bed of a particulate solid material maintained by the gas in the fluidized state and having a temperature of at least 500 DEG C. To produce town gas a heavy fuel oil is treated in a fluidized bed within a vessel 10, Fig. 1, to hydrogenate the more readily reactive constituents at 750 DEG C., the tar being recovered from the gases produced and hydrogenated at 900 DEG C. in a fluidized bed within vessel 11, the pressure being 50 atmospheres in both vessels. The oil is injected at 18 into an upriser 15 and is carried together with fluidized material from stand pipe 13, by the hydrogen-containing gas from line 16 into the vessel 10. The resulting gases pass into vessel 26 for completion of the hydrogenation and then through cooler 27 to condense tar, cooler 28 to condense benzole and washer 29 to remove hydrogen sulfide. Part of the gas is tapped off at 30 to form the hydrogenating gas. This is passed by a blower 37 through a vessel 38 to remove organic sulphur compounds for example by means of alkaline iron oxide at 220 DEG C. Steam and oxygen are then admitted at 39, 40 and the gaseous mixture decomposed in vessel 41 by means of a nickel catalyst at 900 DEG C. into hydrogen and carbon monoxide, the carbon monoxide being then converted by reaction with the excess of steam in vessel 42 and the carbon dioxide removed in a vessel 43. The hydrogenating gas is pre-heated to 350-400 DEG C. at 44 before being supplied to vessels 10, 11 and stand pipes 13, 22. The tar from cooler 27 is injected at 19 into the lower end of an upriser 20 together with solid particles from stand pipe 22 and hydrogenating gas. The gases from vessels 11, 22 are passed through a cooler 31 to remove tar, consisting mainly of crude naphthalene, a cooler 32, to remove benzole, and a hydrogen sulphide washer 33. The gas from washer 33 is mixed at 34 with the portion of the gas from washer 29 which is not used for producing the hydrogenating gas. The mixed gas in line 35 is diluted with nitrogen introduced from line 36 to provide the required town gas. In another embodiment, in which a hydrogen-rich gas is produced, Fig. 2, three fluidized beds 51, 52, 53 are maintained within a vessel 50. A crude petroleum oil is introduced into bed 52, the more reactive constituents being hydrogenated at about 800 DEG C. A light petroleum distillate is hydrogenated in bed 51 at about 700 DEG C. Tar from the beds 51, 52 is hydrogenated at about 900 DEG C. in bed 53. All the hydrogenations are carried out at 30 atmospheres pressure. The resulting gases are passed into cooler 55 in which the tar is condensed which is supplied to bed 53, a cooler 56 to remove benzole, and a hydrogen sulphide washer 57. Organic sulphur compounds are removed in vessel 58 and after the addition of steam at 59 the gaseous mixture is decomposed to form hydrogen and carbon monoxide at 900 DEG C. over a nickel catalyst in vessel 60 the gaseous mixture being pre-heated to 700 DEG C. in a pre-heater 63 by heat exchange with the hot gases leaving the catalyst tubes. 64 is a turbine in which the gases are expanded to five atmospheres. Carbon monoxide is converted with excess of steam by means of an iron-chromium catalyst at 300 DEG C. in vessel 65 into hydrogen. The carbon dioxide so formed is removed at 66, and the gas is cooled to atmosspheric temperature in a cooler 67. A part of the hydrogen-rich gas is withdrawn as product gas at 68 the remainder being passed through compressor 70, pre-heater 71, and line 74 to coils 79, 80 in beds 51, 52, and is discharged at 81 into the space beneath the lowermost bed 53. Coke particles used for the fluidized bed 53 are continuously withdrawn through pipe 76 and returned to bed 51 so that there is a continual downward movement of the particles through the series of beds. The product gas may have the following composition in percentages by volume, carbon dioxide 2.0, carbon monoxide 4.3, hydrogen 91.0, and methane 2.7. In a modification the hydrocarbon containing gas is reacted with oxygen or oxygen and steam at 30 atmosphers pressure instead of the gas being first expanded. In further forms the hydrogenating gas is obtained from a separate source for example water gas may be used.