LOW CARBON DIOXIDE FOOTPRINT PROCESS FOR COAL LIQUEFACTION
A method for producing hydrocarbons is provided, which comprises (a) subjecting a coal feedstock to mechanical activation ( 203 ) in a liquid medium, thereby obtaining a mixture of solubilized asphaltenes; and (b) at least partial cracking ( 207 ) the resulting mixture in a supersonic nozzle reactor, thereby obtaining hydrocarbon products derived from the asphaltenes.
1 . A method for producing hydrocarbons, comprising:
subjecting a coal feedstock to mechanical activation in a first liquid medium containing covalently bound oxygen, thereby obtaining a mixture of solubilized asphaltenes; and
cracking the asphaltenes in a nozzle reactor, thereby obtaining hydrocarbon products derived from the asphaltenes.
2 . The method of claim 1 , wherein the liquid medium comprises an alcohol.
3 . The method of claim 2 , wherein the alcohol is a primary alcohol.
4 . The method of claim 1 , wherein the liquid medium comprises methanol.
5 . The method of claim 1 , wherein the liquid medium comprises an ether.
6 . The method of claim 1 , wherein the liquid medium comprises dimethyl ether.
7 . The method of claim 1 , wherein the liquid medium comprises a methyl carbonate.
8 . The method of claim 1 , wherein the liquid medium comprises a di-methyl carbonate
9 . The method of claim 1 , wherein the liquid medium in an iteration of the method is a portion of the hydrocarbon products generated by a previous iteration of the method.
10 . The method of claim 1 wherein, prior to mechanical activation, the coal feedstock is subjected to an ash removal process.
11 . The method of claim 10 , wherein the ash removal process comprises grinding the coal feedstock.
12 . The method of claim 11 , wherein grinding the coal feedstock produces a ground product having an average particle size within the range of about 1 to about 10 mm.
13 . The method of claim 11 , wherein the ash removal process further comprises subjecting the ground coal feedstock to mineral flotation.
14 . The method of claim 1 , wherein mechanical activation of the coal feedstock generates a mixture comprising asphaltenes and inorganic materials, and further comprising subjecting the mixture to a separation procedure which produces an organic phase rich in asphaltene and an inorganic phase rich in ash.
15 . The method of claim 1 , wherein subjecting the mixture to a separation procedure involves treating the mixture in a centrifuge.
16 . The method of claim 15 , wherein the supernatant obtained from the centrifuge is rich in asphaltenes.
17 . The method of claim 1 , wherein cracking the asphaltenes comprises:
injecting a pressurized stream of cracking material through a cracking material injector and into a reaction chamber of a nozzle reactor; and
injecting a feed material comprising the solubilized asphaltenes into the reaction chamber adjacent to the cracking material injector and transverse to the pressurized stream of cracking material entering the reaction chamber.
18 . The feed material cracking method of claim 18 , wherein the cracking material injector includes a converging/diverging passage.
19 . The method of claim 18 , wherein injecting a pressurized stream of cracking material comprises:
passing the cracking material through the converging/diverging passage; and
accelerating the cracking material to supersonic speed within the cracking material injector.
20 . The method of claim 17 , wherein the feed material is injected into the reaction chamber annularly around the pressurized stream of cracking material.
21 . The method of claim 18 , wherein the feed material is injected into the reaction chamber annularly around the pressurized stream of cracking material.
22 . The method of claim 19 , wherein the feed material is injected into the reaction chamber annularly around the pressurized stream of cracking material.
23 . The method of claim 17 , wherein the cracking material is a cracking gas.
24 . The method of claim 22 , wherein the cracking material is a cracking gas.
25 . The feed material cracking method of claim 17 , wherein the cracking gas comprises steam.
26 . The feed material cracking method of claim 17 , wherein the cracking gas comprises methane.
27 . The feed material cracking method of claim 17 , wherein the cracking gas comprises hydrogen.
28 . A method for cracking coal asphaltenes, comprising:
mechanically activating a coal feedstock in a liquid medium comprising a material which generates hydrogen in situ under a set of cracking conditions; and
cracking the mechanically activated coal feedstock under said cracking conditions.
29 . The method of claim 28 , wherein the material generates hydrogen radicals under said cracking conditions.
30 . The method of claim 28 , wherein the cracking conditions involve exposure of the material to steam.
31 . The method of claim 28 , wherein the cracking conditions involve cracking the asphaltenes in a nozzle reactor.
32 . The method of claim 31 , wherein the nozzle reactor is a supersonic nozzle reactor.
33 . The method of claim 28 , wherein the cracking conditions involve accelerating the asphaltenes to a speed within the range of Mach 1 to Mach 10.
34 . The method of claim 28 , wherein the cracking conditions involve accelerating the asphaltenes to a speed within the range of Mach 2 to Mach 8.
35 . The method of claim 28 , wherein the cracking conditions involve accelerating the asphaltenes to a speed within the range of Mach 4 to Mach 6.
36 . The method of claim 28 , wherein the mechanically activated feedstock absorbs a portion of the material.
37 . A method for cracking coal asphaltenes in a nozzle reactor under a set of reactor conditions, comprising:
providing a nozzle reactor having first and second reactant inlets;
injecting an activated coal feedstock into the first inlet; and
injecting a material into the second inlet which generates hydrogen in situ under said reactor conditions.
38 . The method of claim 37 , wherein the material generates hydrogen radicals in situ under said reactor conditions.
39 . The method of claim 37 , wherein the material is methanol.
40 . The method of claim 39 , wherein the methanol is mixed with steam prior to being injected into the second inlet.
41 . A system for obtaining hydrocarbon liquids from a coal feedstock, comprising:
a grinding mill which mechanically activates the coal feedstock by grinding it in a liquid medium; and
a supersonic nozzle reactor which cracks the activated coal feedstock to generate hydrocarbon liquids.
42 . The system of claim 41 , further comprising:
a separator which separates the ash content from the asphaltene content of the coal feedstock.
43 . The system of claim 41 , wherein the liquid medium comprises an alcohol.
44 . The system of claim 41 , wherein the liquid medium comprises methanol.