We have, in the course of our reportage concerning Coal conversion and Carbon Dioxide recycling technologies, made note of several facts about the known processes for turning those two raw materials into valuable hydrocarbons.
One fact is that some primary processes for transforming either or both of them into other products results in the formation, the deposition on catalyst surfaces, of carbon, or carbonaceous, residues.
The same is true, by the way, of long-practiced techniques for the refining of crude petroleum, and the oil industry has developed efficient technologies for the further conversion of "resids" or petroleum refinery "coke" - essentially carbon deposits - into liquid hydrocarbons.
In any case, the oil industry knows how to convert Carbon, no matter where it comes from, into hydrocarbons, using Steam to provide the Hydrogen; and, that's what this Exxon technology is all about.
As in many Big Oil technologies which can be applied to Coal, use of that offensive four-letter word is avoided as much as possible.
Lest you have any doubts that the technology disclosed herein is applicable to Coal, however, we present, as a foreword, the one passage where it is specified, which will be repeated in our fuller excerpts:
"14. The process of claim 1 wherein said carbonaceous chargestock comprises coal."
The "carbonaceous chargestock", which can be hydrogenated with Steam, can be a lot of other things, too, as should be apparent in our excerpts from:
"United States Patent 4,331,529 - Fluid Coking and Gasification Process
Date: May, 1982
Inventor: Merlan Lambert, et. al., TX and NJ
Assignee: Exxon Research & Engineering Company, NJ
Abstract: An integrated fluid coking and gasification process is provided in which a portion of the coke is gasified in a first gasification zone in the presence of an oxygen-containing gas to produce a hot gas and hot coke. A portion of the resulting hot coke is gasified in a second gasification zone in the presence of steam to produce a gas comprising hydrogen and carbon monoxide, which is suitable, after conventional shift and clean up, for use as synthesis gas.
Claims: An integrated coking and gasification process comprising the steps of:
(a) reacting a carbonaceous chargestock in a coking zone containing a bed of fluidized solids maintained at fluid coking conditions to produce a vapor phase product, including normally liquid hydrocarbons, and coke, said coke depositing on said fluidized solids;
(b) introducing a portion of said solids with the coke deposit thereon to a first fluid bed gasification zone maintained at gasification conditions;
(c) reacting said portion of solids in said first gasification zone with an oxygen-containing gas to produce a first gaseous stream and partially gasified coke and supplying heat from said first gasification zone to said coking zone;
(d) introducing a portion of said partially gasified coke from said first gasification zone to a second fluid bed gasification zone maintained at gasification conditions, said partially gasified coke supplying heat to said second gasification zone;
(e) reacting said portion of partially gasified coke in said second gasification zone with a gas comprising steam in the absence of added oxygen-containing gas to produce a second gaseous stream wherein said second gaseous stream has a higher heating value than the heating value of said first gaseous stream, and
(f) recycling a portion of said partially gasified coke from said second gasification zone to said first gasification zone.
(a) reacting a carbonaceous chargestock in a coking zone containing a bed of fluidized solids maintained at fluid coking conditions to produce a vapor phase product, including normally liquid hydrocarbons, and coke, said coke depositing on said fluidized solids;
(b) introducing a portion of said solids with the coke deposit thereon to a first fluid bed gasification zone maintained at gasification conditions;
(c) reacting said portion of solids in said first gasification zone with an oxygen-containing gas to produce a first gaseous stream and partially gasified coke and supplying heat from said first gasification zone to said coking zone;
(d) introducing a portion of said partially gasified coke from said first gasification zone to a second fluid bed gasification zone maintained at gasification conditions, said partially gasified coke supplying heat to said second gasification zone;
(e) reacting said portion of partially gasified coke in said second gasification zone with a gas comprising steam in the absence of added oxygen-containing gas to produce a second gaseous stream wherein said second gaseous stream has a higher heating value than the heating value of said first gaseous stream, and
(f) recycling a portion of said partially gasified coke from said second gasification zone to said first gasification zone.
13. The process of claim 1 wherein said carbonaceous chargestock comprises a hydrocarbonaceous oil.
14. The process of claim 1 wherein said carbonaceous chargestock comprises coal.
14. The process of claim 1 wherein said carbonaceous chargestock comprises coal.
Summary: (There) is provided ... an integrated coking and gasification process comprising the steps of: (a) reacting a carbonaceous chargestock in a coking zone ... to produce a vapor phase product, including normally liquid hydrocarbons, and coke ... ; (b) introducing a portion of said solids with the coke deposit thereon to a first fluid bed gasification zone maintained at gasification conditions; (c) reacting said portion of solids in said first gasification zone with an oxygen-containing gas to produce a first gaseous stream and partially gasified coke; (d) introducing a portion of said partially gasified coke from said first gasification zone to a second fluid bed gasification zone maintained at gasification conditions; (e) reacting said portion of partially gasified coke in said second gasification zone with a gas comprising steam to produce a second gaseous stream ... ."
----------
In essence, and in one aspect, this technology proposes a straightforward initial thermal gasification of Coal, to derive a first cut of: "a vapor phase product, including normally liquid hydrocarbons".
The remaining carbonaceous "solids" from the "first gasification zone" are then forwarded to a "second gasification zone" where they are reacted with "steam to produce a second gaseous stream".
That "second gaseous stream", fully-hydrogenated by reaction with Steam, would then, like the initial product from the "first gasification zone" be "suitable ... for use as synthesis gas".
Synthesis gas, to be tedious, can then be passed over Fischer-Tropsch, for instance, and generically related, catalysts; and, thus converted into "normally liquid hydrocarbons".
Note, too, in confirmation of other, related Coal conversion technologies we have reported, that heat is generated as one function of the process, which can then be recycled to help drive other steps in the total system, as in: "said partially gasified coke supplying heat to said second gasification zone".
Thermal efficiencies are thus achieved; and, in essence, as in other expositions of similar technology we have recorded for you, all of the energy needed to convert Coal into "normally liquid hydrocarbons" can be derived from Coal.
Again, Coal is mentioned only once on the full Disclosure, but Coal, as being representative of Carbon, is really what it is all about.
We can, as herein, convert it, thoroughly and completely, into "synthesis gas" and "liquid hydrocarbons".