Method for extracting biochemical products obtained from a process of hydrothermal carbonization of biomass

Abstract

The invention relates to a method for extracting biochemical products obtained from a process of hydrothermal carbonization of biomass, which includes feeding an aqueous mixture of biomass from a preheating tube for the aqueous mixture of biomass to a vertical reactor with a predetermined level of floatation and an area for accumulation of steam and gases in the upper part thereof, wherein said method for extracting biochemical products is characterized in that it includes (a) heating the aqueous mixture of biomass to, or above, evaporation temperature in said vertical reactor and/or in a previous stage of preheating the aqueous mixture of biomass, increasing the generation of stream and/or gases at the predetermined flotation level of the vertical reactor, (b) extracting the steam and/or gases generated in the previous stage and accumulated in the upper part of the vertical reactor, and (c) cooling the gases and/or condensing the steam extracted in the previous stage at different levels of temperature and pressure. The invention likewise relates to the biochemical product obtainable from said method, as well as to a system for implementing said method.

Claims

1. A method for extracting biochemical products during a process of hydrothermal carbonization of biomass, comprising feeding an aqueous mixture of biomass from a preheating tube to a vertical reactor with a defined level of flotation and an area for the accumulation of steam and gases in its upper portion, wherein said method for extracting biochemical products comprises: (a) Heating the aqueous mixture of biomass up to or over an evaporation temperature of the biomass in the vertical reactor by means of a direct injection of at least one saturated overheated steam and/or of hot gases into the vertical reactor itself, below the defined level of flotation of the aqueous mixture of biomass to increase the generation of steam and/or gases at the set level of flotation of the vertical reactor and to release and form biochemical products; (b) Extracting the biochemical products alongside the steam and/or gases generated in the previous stage, which accumulated in the upper portion of the vertical reactor during a monomerization stage of the hydrothermal carbonization of biomass process; (c) Cooling the gases and/or condensing the steam extracted in the previous stage at differing temperature and pressure levels; and (d) Separating the biochemical products from the cooled gases and/or the condensed steam generated in step c).

2. The method, according to claim 1, wherein the vertical reactor is a vertical reverse flow reactor comprising an ascent tube inside the vertical reverse flow reactor, wherein the monomerization of the aqueous mixture of biomass is started in the ascent tube.

3. The method, according to claim 1, further comprising an additional preheating stage of the aqueous mixture of biomass which takes place in a preheating tube, by means of the circulation of a heat carrying fluid through a jacket located in the external portion of said preheating tube, by means of the direct injection of at least one saturated or overheated steam into said preheating tube, by means of the direct injection of hot gases into said preheating tube or by means of any combination thereof.

4. The method, according to claim 2, wherein said heating of the aqueous mixture of biomass takes place by means of the direct injection of at least one saturated or overheated steam and/or hot gases into the ascent tube of the vertical reverse flow reactor.

5. The method, according to claim 1, comprising an additional pressure and temperature regulation stage of the steam and/or gases with the biochemical products in a pressure regulation deposit.

6. The method, according to claim 1, wherein the condensation of steam takes place in at least one piece of condensation equipment and/or a jacket of a preheating tube located before the vertical reactor.

7. The method, according to claim 1, wherein separation of the biochemical products from the cooled gases and condensed steam is carried out by a separation technique selected from the group consisting of decanting, extraction, distillation, filtration, centrifugation, and any combination thereof.

8. The method, according to claim 7, wherein at least a part or all of the separated condensed products are chemically evaluated and/or driven to at least one condensed product deposit and from there, fed back into the vertical reactor.

9. The method, according to claim 1, further comprising an additional step of producing liquid fuels by means of catalytic transformation using the biochemical product produced by said method.

10. The method, according to claim 1, further comprising an additional step of producing liquid fuels by means of a hydrogenation process using the biochemical product produced by said method.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a diagram of the process, object of the present invention. Please find a list of the references used in this figure below:

(2) 1. Storage hopper.

(3) 2. Mixture of biomass, process water and catalyst.

(4) 3. Compression pump.

(5) 4. Gate valve.

(6) 5. Preheating tube.

(7) 6. Hot fluid.

(8) 7. Vertical reverse flow reactor.

(9) 8. Ascent tube.

(10) 9. Monomerization area.

(11) 10. Gas and water vapor area.

(12) 11. Polymerization area.

(13) 12. Maturity area.

(14) 13. Pressure regulation deposit.

(15) 14. Regulation valve.

(16) 15. Regulation valve.

(17) 16. Piece of cooling equipment.

(18) 17. Decompression valve.

(19) 18. Flash deposit.

(20) 19. Decompression valve.

(21) 20. Heat exchanger.

(22) 21. Condensed products deposit.

(23) 22. Final product.

(24) 23. Steam boiler.

(25) 24. Regulation valve.

(26) 25. System for injecting steam into the reactor.

(27) 26. Piece of (biochemical substance) separation equipment.

(28) 27. Evaporation device.

(29) 28. Valve.

(30) Flows:

(31) A. Coolant fluid I

(32) B. Coolant fluid II

(33) C. Heat flow I

(34) D. Heat flow II

PREFERRED EMBODIMENT OF THE INVENTION

(35) Below, a particular embodiment of the object of the present invention is set out by way of a non-limiting example, as represented in FIG. 1. This figure is based on the hydrothermal carbonization of biomass process, as described in patent ES2339320. As can be seen in the figure, the process begins in the storage hopper (1), from where a biomass mixture leaves towards the compression pump (3) wherein it is compressed to a pressure of at least 13 bars, which is the pressure of the reactor plus the pressure required to conquer the counter pressure created in the course of the preheating tube (5) and the ascent tube (8). It is then transported along the length of the preheating tube (5), until a temperature of around 180 C. is reached. Following this heating stage, the mixture is fed into the vertical reverse flow reactor (7), which is 6 m long with a 1 m diameter, via the ascent tube (8), which is 20 cm in diameter and occupies 60% of the height of the reactor.

(36) Then, should the reactor have a cold start, vapor is injected at a temperature of around 195 C., through the lower portion of the same, both through the ascent tube (8) and through the maturity area (12), until the temperature and pressure needed for the process are obtained, therefore beginning the monomerization stage. At the same time, owing to the natural break down of the biomass itself, gases begin to be got rid of, for example methane or CO.sub.2, which rise up the inside of the ascent tube (8) until they accumulate in the high portion of the reactor (10). From there, they are evacuated, alongside the saturated steam, towards a pressure regulation deposit (13).

(37) Meanwhile, once they reach the output of the ascent tube (11), the products resulting from the first monomerization stage start the second, polymerization stage, during which they are transformed into a kind of resin or pre-carbon state. Furthermore, during this stage, since it is an exothermic stage by nature, it will be necessary to contribute a certain amount of process water in order to successfully keep the operating temperature stable, at around 191 C., as well as to ensure a constant volume in the reactor. This provision of condensed products is made via the valve (14) and comes from the pressure regulation deposit (13).

(38) Once 3 hours have passed, the solid components are dense enough to be able to start their descent towards the maturity area (12), where they will remain for 8 hours or more, until their thermal activity is reduced to practically zero.

(39) In additional, an evaporation device (27) is available, in which part of the product of the reaction coming from the maturity stage (12) is heated and evaporated in such a way that the gasses generated are reintroduced into the vertical reverse flow reactor (7) via the valve (28) and the steam injection system to the reactor (25). This evaporation device (27) in turn comprises an external heat supply system (c) which serves to keep the temperature constant.

(40) Once the carbonization process has come to an end, the carbonized biomass mixture and process water enter into the piece of cooling equipment (16), where their temperature is reduced to around 90 C. Finally, once cooled, the mixture is extracted via the decompression valves (17) and (19), passing through the intermediate flash deposit (18), thereby producing a product composed by a liquid stage and by solid carbonized biomass particles.

(41) In order to maximize the recovery of biochemical products produced during the monomerization stage of the process, the steams and gases generated and accumulated in the high portion of the reactor (10) are directed directly from the reverse flow reactor (7) towards the pressure regulation deposit (13). In turn, the gases originating from this pressure regulation deposit (13) are sent to the heat exchanger (20) or to the preheating tube (5), which act as pieces of condensation equipment to accelerate the condensation of the steam. In this case, the pressure regulation deposit (13) is located parallel to said piece of condensation equipment, and on occasion, may remain without steam transfer.

(42) After having obtained the condensed steam products and biochemical products (comprising oils, etc.), said condensed product is driven to pieces of separation equipment (26), such as pieces of decantation, extraction, distillation, centrifugation and filtration equipment, etc., where the oils and biochemical products are separated and the swept gasses are extracted. Once the biochemical products have been separated, the condensed product remnants, comprising a mixture of different acids and water, may be chemically evaluated and/or driven to at least one condensed product deposit (21) and from there, they may be fed back into the process.