Hydroliquefaction of Coal

FIG. 1 is a simplified schematic flow diagram of an embodiment of the present invention; and

FIG. 2 is a top cross-sectional view of a reactor to illustrate a form of the partitions.

It is to be understood that the embodiment is only schematically shown, and various equipment, such as pumps, heat exchangers and the like have been omitted for simplifying the description of the embodiment. The use of such equipment at suitable places is well within the scope of those skilled in the art from the teachings herein.

Referring now to the drawing, coal in line 10 and a suitable pasting solvent in line 11, generally recovered from the hydroliquefaction product, are introduced into a slurry tank 12 to disperse the coal in the pasting solvent. A slurry of coal in pasting solvent is withdrawn from tank 12 through line 13, combined with recycle in line 14, as hereinafter described, and the combined stream in line 15 is introduced into the first of three hydroliquefaction reactors 16, 17 and 18, respectively. Heated hydrogen in line 19 is also introduced into the first of the three hydroliquefaction reactors 16, 17 and 18.

Each of the hydroliquefaction reactors 16, 17 and 18 includes at least two parallel expanded or ebullated beds of hydroliquefaction catalyst, each of which is designed and operated to provide for upward flow of hydrogen and coal dispersed in solvent through the bed as a stream having a cross-sectional flow area through the catalyst bed of no greater than 255 square inches, and a Peclet Number of at least 3. As shown in FIG. 2, such parallel beds in reactors 16, 17 and 18 are formed by a honeycomb shaped partition 41, which as particularly shown defines 19 parallel beds. It is to be understood that more or less parallel beds could be employed and/or the parallel beds could be formed by other than honeycomb shaped partitions. Reactors 16, 17 and 18 are operated without any internal recycle. Thus, as hereinabove described, the length of each of the catalyst beds in each of the reactors as well as the liquid and gas superficial velocities are coordinated with the stream cross-sectional flow area through each of the catalyst beds in each of the reactors to provide a Peclet Number of at least 3. The hydroliquefaction reactors 16, 17 and 18 are operated at the temperatures and pressures hereinabove described to effect hydroliquefaction of the coal, and in addition, hydrodesulfurization and hydrodenitrification thereof. The coal dispersed in the pasting solvent is passed in parallel flow streams through the catalyst beds in reactor 16, the combined effluent from reactor 16 is passed in parallel flow streams through the catalyst beds in reactor 17, and the combined effluent from reactor 17 is passed in parallel flow streams through the beds in reactor 18.

Hydroliquefaction effluent, withdrawn from reactor 18 through line 21, is introduced into a gas-liquid separator 22 to recover a portion of the liquid product in line 23, with the remaining portion of the effluent in line 24 being passed through a suitable cooler 25 and introduced into a second separator 26 to recover further liquid product through line 27. The net hydroliquefaction product is recovered through line 28 for further treatment, as known in the art.

Recycle product is recovered through line 14, and as hereinabove noted, the recycle in line 14 is primarily for the purpose of providing sufficient liquid in the hydroliquefaction reactors 16, 17 and 18 to maintain the catalyst as expanded beds. The recycle amounts are limited as hereinabove described.

Gas is recovered from separator 26 through line 31 and a portion thereof is purged through line 32. The remaining portion is compressed in compressor 33, combined with make-up hydrogen in line 34 and the combined stream passed through a suitable heater 35 to provide heated hydrogen to the hydroliquefaction through line 19.

The hereinabove described embodiment is only illustrative of the present invention, and as a result, such an embodiment may be modified within the spirit and the scope of the present invention. Thus, the hydroliquefaction may be effected in more or less than three zones, as particularly described. Similarly, product recovery may be effected other than as particularly described.

These and other modifications should be apparent to those skilled in the art from the teachings herein.

The invention will be further described with respect to the following Example; however, the scope of the invention is not to be limited thereby:

The following is illustrative of a reaction system and conditions for practising the present invention. The system includes three reactors in series using cobalt molybdate supported on alumina as catalyst. The system is suitable for hydroliquefaction of Illinois No. 6 coal, as a representative example. Each of the reactors has the following characteristics and is operated at the following conditions:

The present invention is particularly advantageous in that there is provided improved selectivity to liquid product which increases overall hydrogen efficiency. As a result, the present process is more economic than the hydroliquefaction processes previously employed in the art. In addition, such increased hydrogen efficiency may be obtained in reactors having total cross-sectional areas suitable for commercial applications.

Thus, by proceeding in accordance with the invention it is possible to achieve a 90% or greater conversion of moisture ash free (MAF) coal with hydrogen consumptions of 2-4 lbs. hydrogen per 100 lbs. coal, as compared to previous hydrogen consumptions in excess of 4%, and in most cases in excess of 4.5%.

These and other advantages sould be apparent to those skilled in the art from the teachings herein.

Numerous modifications and variations of the present invention are possible in light of the above teachings and, therefore, within the scope of the appended claims, the invention may be practised otherwise than as particularly described.