Production of oil and high Btu gas from coal

#This application is related to my co-pending applications Ser. No. 268,201 filed June 30, 1972 now U.S. Pat. No. 3,823,084 and Ser. No. 412,026 filed Nov. 1, 1973.

#The present invention relates to the conversion of coal into liquid and gaseous hydrocarbon products by reacting hydrogen with the chemical substituents of coal in a closed, cyclic, high pressure system through which hydrogen is circulated. The only raw materials fed to the system are coal, oxygen and water. Hydrogen required for the hydrogenation is produced from the coal.

#My prior U.S. Pat. Nos. 3,030,297, issued Apr. 17, 1962, and 3,152,063, issued Oct. 6, 1964, disclose coal hydrogenation processes and set forth the general conditions of temperature, pressure and time under which coal can be hydrogenated to produce oil and gas. In the processes of these patents, reactions between coal and hydrogen were carried out in the presence or absence of catalysts. At higher temperatures, catalysts were found to have relatively small effect. Gases resulting from these reactions were largely hydrocarbons mixed with the hydrogen gas used to hydrogenate the coal. Generally the hydrocarbon gases were in a range from 5 to approximately 35 volume percent of the gaseous products. My U.S. Pat. No. 3,762,773, issued Oct. 2, 1973, discloses a method and apparatus for feeding finely divided solids such as coal, to a pressurized gas or gas-liquid-solid system without loss of gas pressure from the pressurized system.

#This invention is illustrated by the accompanying drawings, wherein:

#FIG. 1. A and 1B together represent a flow diagram of a coal hydrogenation system embodying the principles of the invention.

#FIG. 1C is a flow diagram of a modified form of that portion of the system shown in FIG. 1A.

#Referring to the flow diagram of FIGS. 1A and 1B, solid pulverized coal from a pressurized feeder vessel 1 or 2 is fed through line 3, line 5, and flow controller 4 into line 6. Preheated recycled hydrogen gas from the process flows through line 57 and joins the stream of coal in line 6. Recycled hydrogen gas which has not been preheated may be used to pressurize the coal feeders 1 and 2 through line 56 as shown.

#Fresh hydrogen in sufficient quantity to supply all of the hydrogen requirements for the process is produced in coal gasifier 7. One means of producing the hydrogen in gasifier 7 is as follows: coal from the pressurized feeding units 1 or 2 flows through line 9 to flow controller 8 and then through line 12 to coal gasifier 7, which is operated at the pressure of the closed cyclic system. The pressure in the system is generally within the range of from about 1000 to 5000 psi, with the pressure in the hydrogen recycle lines 56 and 57 being slightly higher than that in the gasification and hydrogenation units in order to ensure flow through the system. Steam at the required pressure is generated from waste heat from the gasification operation and is fed to the gasifier through line 10. Oxygen generated at systems pressure in an air separation plant (not shown) is fed to the gasifier through line 13. It is desirable to preheat this oxygen to about 1000.degree.F before it is fed to the gasifier.

#The gasifier is preferably a refractory lined high pressure steel vessel equipped with a jacket for water cooling. Reactions in the gasifier between coal, oxygen and steam generate largely hydrogen and carbon monoxide, along with a small amount of carbon dioxide. It is desirable to run the gasifier at high temperatures since this increases the speed of the reactions and especially the rate of steam decomposition. It also reduces the amount of carbon dioxide in the gas. Operating temperature in the gasifier should not be below 2000.degree.F and may be as high as 3000.degree.F.