Catalytic process for liquefying coal

Claim 2

A process for liquefying coal at a hydrogen pressure above 3,100 psi comprising passing a feed coal-solvent slurry and hydrogen through a tubular preheater zone to heat the slurry to a maximum temperature of about 710° to about 800° F., passing effluent slurry from said preheater zone to a non-catalytic dissolver zone maintained at a hydrogen pressure above 3,100 psi and at a temperature at least 10° F. higher than the maximum temperature in the preheater zone in the range of about 800° to about 900° F., the residence time in the dissolver zone being longer than in the preheater zone, removing an effluent stream from said dissolver zone, passing said dissolver effluent stream without a distillation step and at a hydrogen pressure above 3,100 psi through a catalytic hydrogenation zone maintained at a temperature in the range of 700° to 825° F., removing a catalytic hydrogenation zone effluent stream and recovering a solvent boiling range fraction therefrom, and recycling said solvent fraction to form said feed coal-solvent slurry.

Claim 3

The process of claim 1 wherein the hydrogen pressure is above about 3,500 psi.

Claim 4

The process of claim 1 wherein the preheater zone maximum temperature is 750° to 790° F.

Claim 5

The process of claim 1 wherein said dissolver zone effluent stream is cooled by quenching with hydrogen.

Claim 6

The process of claim 1 wherein the dissolver zone temperature is at least 50° F. higher than the preheater zone temperature.

Claim 7

The process of claim 1 wherein the dissolver zone temperature is at least 100° F. higher than the preheater zone temperature.

Claim 8

A process for liquefying coal at a hydrogen pressure above 3,100 psi comprising passing a feed coal-solvent slurry and hydrogen through a tubular preheater zone to heat said slurry to a maximum temperature of about 710° to about 800° F., passing effluent slurry from said preheater zone to a non-catalytic dissolver zone maintained at a hydrogen pressure above 3,100 psi and at a temperature at least 10° F. higher than the maximum temperature in the preheater zone in the range of about 800° to about 900° F., the residence time in the dissolver zone being longer than the residence time in said preheater zone and being between about 5 and 60 minutes during which ash-containing slurry settles from supernatant liquid in said dissolver zone, removing said supernatant liquid from said dissolver zone, separately removing ash-containing slurry from said dissolver zone, passing said supernatant liquid without a distillation step and at a hydrogen pressure of at least 3,100 psi to a catalytic hydrogenation zone maintained at a temperature in the range of 700° to 825° F., removing a catalytic hydrogenation zone effluent stream and recovering a solvent boiling range fraction therefrom, and recycling said solvent fraction to form said feed coal-solvent slurry.

Claim 9

A process for liquefying coal at a hydrogen pressure above 3,100 psi comprising passing a feed coal-solvent slurry and hydrogen through a tubular preheater zone to heat said slurry to a maximum temperature of about 710° to about 800° F., passing effluent slurry from said preheater zone to a non-catalytic dissolver zone maintained at a hydrogen pressure above 3,100 psi and at a temperature at least 10° F. higher than the maximum temperature in the preheater zone in the range of about 800° to about 900° F., the residence time in the dissolver zone being longer than the residence time in said preheater zone and being between about 5 and 60 minutes during which ash-containing slurry settles from supernatant liquid in said dissolver zone, removing said supernatant liquid from said dissolver zone, separately removing ash-containing slurry from said dissolver zone, passing said supernatant liquid without a distillation step and at a hydrogen pressure of at least 3,100 psi to a catalytic hydrogenation zone maintained at a temperature in the range of 700° to 825° F., removing a catalytic hydrogenation zone effluent stream and recovering a solvent boiling range fraction therefrom, and recycling said solvent fraction to form said feed coal-solvent slurry.

Claim 10

The process of claim 7 wherein said ash-containing slurry is passed through a solids-liquid separator means.

Claim 11

The process of claim 7 wherein the residence time in said preheater zone is between about 2 and 20 minutes.

Claim 12

The process of claim 7 including a hydroclone operating in association with said dissolver zone to separate solids from liquid in said ash-containing slurry, and recycling separated liquid from said hydroclone to said dissolver zone.

Claim 13

The process of claim 7 wherein at least 4,000 SCF of hydrogen per ton of said feed coal are chemically consumed in said catalytic hydrogenation zone.

Claim 14

The process of claim 7 wherein the hydrogen pressure is at least 3,500 psi.

Claim 15

The process of claim 7 wherein the temperature in the dissolver zone is at least 50° F. higher than the temperature in the preheater zone.

Claim 16

The process of claim 7 wherein said supernatant liquid is cooled by quenching before being passed to said catalytic hydrogenation zone.

Claim 17

The process of claim 7 wherein the temperature in the dissolver zone is at least 100° F. higher than the temperature in the preheater zone.

Claim 18

The process of claim 1 wherein said dissolver effluent stream is passed to said catalytic hydrogenation zone without a solids removal step.

Claim 19

The process of claim 1 wherein the temperature in the catalytic hydrogenation zone is lower than in the dissolver zone.

Claim 20

The process of claim 1 wherein the liquid residence time in the catalytic hydrogenation zone is lower than in the dissolver zone.

Claim 21

The process of claim 7 wherein the temperature in the catalytic hydrogenation zone is lower than in the dissolver zone.

Claim 22

The process of claim 7 wherein the liquid residence time in the catalytic hydrogenation zone is lower than in the dissolver zone.