Process for producing liquid hydrocarbon
The invention relates to a continuous process for converting carbonaceous material contained in one or more feedstocks into a liquid hydrocarbon product, said feedstocks including the carbonaceous material being in a feed mixture including one or more fluids, said fluids including water and further liquid organic compounds at least partly produced by the process in a concentration of at least 1% by weight, where the process comprises converting at least part of the carbonaceous material by pressurizing the feed mixture to a pressure in the range 250-400 bar; heating the feed mixture to a temperature in the range 370-450° C., and maintaining said pressurized and heated feed mixture in the desired pressure and temperature ranges in a reaction zone for a predefined time; cooling the feed mixture to a temperature in the range 25-200° C. and expanding the feed mixture to a pressure in the range of 1-70 bar, thereby causing the carbonaceous material to be converted to a liquid hydrocarbon product and separating from the converted feed mixture a fraction comprising liquid hydrocarbon product.
1. A continuous process for converting one or more carbonaceous feedstocks into a liquid hydrocarbon product, the process comprising:
providing a feed mixture comprising said one or more carbonaceous feedstocks and water,
adding liquid organic compounds to the feed mixture, wherein the liquid organic compounds comprise at least 5% by weight of the feed mixture,
passing said feed mixture to a reaction zone,
converting at least part of the one or more carbonaceous feedstocks in the feed mixture into a liquid hydrocarbon product by:
pressurizing the feed mixture to a pressure in the range of 250-400 bar,
heating the feed mixture to a temperature in the range of 370-450° C., and
maintaining said pressurized and heated feed mixture in said pressure and temperature ranges in the reaction zone for a predefined time, thereby producing a converted feed mixture containing CO 2 ;
cooling the converted feed mixture to a temperature in the range of 100-200° C. to produce a cooled and converted feed mixture
depressurizing the cooled and converted feed mixture below the critical pressure of CO 2 by expanding the cooled and converted feed mixture to a pressure in the range of 1-70 bar, to produce an expanded and cooled converted feed mixture
separating the expanded and cooled converted feed mixture into a stream comprising the liquid hydrocarbon product and a water phase comprising at least part of the liquid organic compounds which are water phase liquid organic compounds; and
recovering at least part of the water phase liquid organic compounds from the water phase and adding at least part of the recovered water phase liquid organic compounds to the feed mixture.
2. The process according to claim 1 , wherein the liquid organic compounds comprise at least 10% by weight of the feed mixture.
3. The process according to claim 1 , where the feed mixture further contains at least one homogeneous catalyst comprising a compound of potassium and/or sodium in an amount of at least 0.5% by weight based on the dry weight of the one or more carbonaceous feedstocks in the feed mixture.
4. The process according to claim 1 , wherein the weight ratio of said liquid organic compounds to the dry weight of the one or more carbonaceous feedstocks in said feed mixture is in the range of 0.1 to 2.0.
5. The process according to claim 1 , wherein the pressure during said pressurizing step is in the range of 275 to 350 bar.
6. The process according to claim 1 , wherein the temperature during said heating step is in the range of 380 to 430° C.
7. The process according to claim 1 , wherein said pressurizing the feed mixture occurs prior to said heating the feed mixture.
8. The process according to claim 1 , further comprising measuring a pH during and/or after the conversion, and adding a base to the feed mixture when the measured pH is below 8.
9. The process according to claim 1 , wherein the heating of the feed mixture to 370-450° C. comprises heating the feed mixture at a rate of at least 50° C./min while the feed mixture is still in the temperature range of 140-300° C.
10. The process according to claim 1 , where the average flow velocity in pipes in the process and/or at the entry of the reaction zone is at least 0.2 m/s.
11. The process according to claim 1 , further comprising recovering additional substances from the water phase, wherein said recovery of additional substances is performed in one or more evaporators and one or more condensers, and wherein a first of said one or more evaporators is adapted to perform a vapor recompression technique and/or a thermal recompression technique.
12. The process according to claim 11 , wherein said additional substances being recovered comprise a homogeneous catalyst in the form of potassium and/or sodium, wherein at least part of said recovered substances is introduced into said feed mixture in a concentrated form.
13. The process according to claim 1 , wherein said step of cooling the converted feed mixture comprises cooling said converted feed mixture at the pressure used for pressurizing the feed mixture to a temperature in the range of 100-200° C. by heat exchange with the feed mixture passed to said reaction zone, and wherein said expanding the cooled feed mixture takes place in one of more steps, with at least one of said expansion steps comprising an expansion in a flash separator to a pressure in the range of 50 to 70 bar, thereby producing a gas phase and a liquid phase, and wherein the process further comprises:
(i) cooling the gas phase in a first condenser to a temperature in the range of 35 to 80° C. to produce a cooled gas phase; and
(ii) cooling the cooled gas phase to a temperature in the range of 12-30° C., thereby producing a condensate comprising liquid CO 2 .