A device for treating organic waste to produce hydrogen, organic acid and biochar

Abstract

The present invention belongs to the technical field of organic waste resource utilization, and particularly relates to a device for treating organic waste to jointly produce hydrogen, organic acid and biochar, the device comprising a liquid storage tank, a dry fermentation reactor, a heating furnace and a fractionating tower; the dry fermentation reactor comprising a sprayer, a leachate collection area, an agitator, a sieve plate, an air outlet, a feed pipe and a sealing cover; the present invention has a mutually independent fermentation acid and hydrogen production area and a residue pyrolysis area, and the two processes are carried out separately to achieve full resource utilization of organic waste, inhibit methanogens by controlling the temperature of the reflux liquid, thereby avoiding the generation of methane gas during the fermentation process, increasing the output of products such as organic acid and hydrogen, and achieving continuous inoculation of acid-producing bacteria in anaerobic fermentation reactions; at the same time, the circulation of liquid in the environmental control system reduces water consumption compared to traditional anaerobic fermentation devices, thereby improving the economic efficiency of equipment operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic waste resource utilization, and in particular relates to a device for treating organic waste to jointly produce hydrogen, organic acid and biochar. Background Art

[0002] Anaerobic fermentation technology has been successfully applied to the energy and resource conversion of various organic wastes. Unlike conventional anaerobic fermentation, which primarily produces methane, anaerobic fermentation produces acid and hydrogen under the action of acid-producing bacteria. First, acid-producing bacteria ferment the monomers of the hydrolyzate into acetic acid, propionic acid, butyric acid, alcohols, hydrogen, carbon dioxide, and other solvents. Propionic acid, butyric acid, alcohols, and carbon dioxide are then further converted to acetic acid via either a proton reduction acetyl pathway or a homoacetyl pathway. Typically, acetic acid, propionic acid, and butyric acid are the primary organic acid products of anaerobic fermentation of organic waste. Current research indicates that anaerobic fermentation not only produces organic acids with greater potential for application than conventional anaerobic fermentation, but also reduces water consumption during the fermentation process, increases the added value of the fermentation products, and significantly improves the economic efficiency of the fermentation process. Furthermore, anaerobic fermentation systems are capable of withstanding higher organic loadings.

[0003] Chinese patent CN107083401A discloses a method for resource utilization of agricultural organic waste, converting the products of anaerobic dry fermentation into methane, ethanol, and lignin. Chinese patent CN105861306A discloses a solid-liquid two-stage anaerobic fermentation apparatus and method. By efficiently coupling a solid acid-producing fermentation reactor with a liquid methanogenic reactor (effectively matching their effective volume and quantity), this achieves a balance between acid-producing and methanogenic fermentation, improving biogas production efficiency.

[0004] Chinese patent CN104357487A discloses a method for efficiently producing biogas through mesophilic anaerobic dry fermentation of agricultural waste. This method addresses the issues of long fermentation times, low gas production, and acidification associated with separate anaerobic fermentation of individual materials. It significantly increases the system's buffering capacity, reduces the inhibitory effects of excessive concentrations of ammonia nitrogen or other inhibitors, broadens the selection of fermentation feedstocks, and enhances the treatment of organic solid waste.

[0005] Chinese patent CN1047064A discloses a method for producing activated carbon from the waste residue of citric acid fermentation from dried potatoes. This method, which utilizes the waste from citric acid fermentation from dried potatoes to produce activated carbon, opens up a new raw material for the production of activated carbon, reduces production costs, and fundamentally addresses the environmental pollution problem posed by the waste residue from citric acid fermentation from dried potatoes, transforming waste into valuable resources with significant economic and social benefits.

[0006] Based on existing research and the technologies and processes described in patents, anaerobic fermentation of organic waste currently primarily utilizes a medium-temperature, continuously stirred wet anaerobic process. This process presents challenges such as complex pretreatment, low load tolerance, scum formation, high water consumption, difficulty in handling both sludge and liquid biogas, and a prolonged fermentation reaction cycle. Furthermore, the methane produced as the primary product is of low value, resulting in poor economic viability. Summary of the Invention

[0007] The purpose of the present invention is to provide a device for treating organic waste to jointly produce hydrogen, organic acid and biochar. The device addresses the shortcomings of the existing technology and completes the anaerobic fermentation hydrogen and acid production processes of organic waste and the product separation and biochar production processes in the same device, thereby realizing efficient integration of anaerobic fermentation of organic waste and product separation.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] An apparatus for treating organic waste to co-produce hydrogen, organic acid, and biochar, the apparatus comprising a liquid storage tank 1, a dry fermentation reactor 2, a heating furnace 6, and a fractionating tower 8;

[0010] The dry fermentation reactor 2 includes a sprayer 3, a leachate collection area 4, an agitator 11, a sieve plate 12, an air outlet 16, a feed pipe 17 and a sealing cover 20;

[0011] The dry fermentation reactor 2 is provided with a sealing cover 20 at the material inlet, a sprayer 3 connected to the liquid outlet pipe 15 and an outlet 16 connected to the gas collection device on the top, an agitator 11 is provided inside, and a leachate collection area 4 is provided below. A feed pipe 17 connected to the heating furnace 6 is provided on the side opposite to the material inlet; a screw push rod is provided in the feed pipe 17; a sieve plate 12 is provided on the top of the leachate collection area 4, and the bottom is connected to the liquid inlet pipe 14;

[0012] The liquid storage tank 1 is arranged on the side of the dry fermentation reactor 2, and the interior of the liquid storage tank 1 is divided into a liquid storage area and a pipeline area by the inner wall. The liquid storage tank 1 is provided with an opening connected to the liquid inlet pipe 14 through a valve 19; the liquid storage area is used to store buffer and water, and the pipeline area is used to place the liquid inlet pipe-liquid storage tank section pipeline; a pump 18 is provided at the bottom of the storage area; the pump 18 is connected to the leachate collection area 4 and the liquid storage area in the horizontal direction through the liquid inlet pipe 14, and is connected to the heat exchange pipe 9 in the vertical direction through the liquid inlet pipe 14, so as to exchange heat between the liquid in the pipe and the fractionation tower 8;

[0013] The heating furnace 6 is provided between the dry fermentation reactor 2 and the fractionation tower 8. The bottom of the heating furnace 6 is provided with a fuel storage and combustion area 5, the furnace wall is provided with a pH control system 7, and the upper part is provided with a steam outlet connected to the fractionation tower 8;

[0014] The distillation tower 8 is provided with an organic acid collection area 13 in the tower body, a first outlet connected to the steam outlet of the heating furnace 6 and a second outlet connected to the upper end of the reboiler 10 are provided in the middle and lower part of the tower wall, a third outlet connected to the reflux pipe of the reboiler 10 is provided at the bottom of the tower, and a fourth outlet for exhaust gas discharge is provided at the top of the tower. A heat exchange tube 9 is wound around the outside of the tower wall and connected to the liquid inlet pipe 14 and the liquid outlet pipe 15.

[0015] The dry fermentation reactor 2 is a plug flow reactor.

[0016] The sludge inoculated with organic waste in the dry fermentation reactor 2 is heated at above 70° C. to remove methanogens.

[0017] The heating temperature of the heating furnace 6 is 200-300°C.

[0018] The inorganic acids used in the pH control system 7 are phosphoric acid, sulfuric acid and hydrochloric acid. The pH of the fermentation product needs to be adjusted to 2-3 before heating in the heating furnace 6.

[0019] The fractionation tower 8 is a plate tower.

[0020] The reboiler 10 is set at a temperature of 150-180°C.

[0021] The liquid outlet pipe 15 is provided with a pH monitoring system and a temperature monitoring system.

[0022] In the equipment for co-producing hydrogen, organic acid and biochar, except for the heat exchange pipe 9 and the feed pipe 17, the outer walls of other pipes are provided with insulation layers to reduce heat loss.

[0023] The solid content of the organic waste is 15-50%.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1) The equipment for treating organic waste to produce hydrogen, organic acid and biochar of the present invention has independent fermentation, acid and hydrogen production zones and residue pyrolysis zones. By carrying out the two processes separately, the full resource utilization of organic waste is achieved.

[0026] 2) The device for treating organic waste to co-produce hydrogen, organic acid and biochar of the present invention suppresses methanogens by controlling the temperature of the reflux liquid, thereby avoiding the production of methane gas during the fermentation process and increasing the output of products such as organic acid and hydrogen.

[0027] 3) The equipment for treating organic waste to co-produce hydrogen, organic acid and biochar of the present invention controls the temperature and pH of the fermentation reaction through an environmental control system, thereby ensuring the efficient progress of the fermentation reaction and improving the energy utilization rate of the equipment.

[0028] 4) The device for treating organic waste for the co-production of hydrogen, organic acid, and biochar of the present invention achieves continuous inoculation of acid-producing bacteria in the anaerobic fermentation reaction by spraying the reflux liquid in the liquid outlet pipe; at the same time, the circulation of the liquid in the environmental control system reduces water consumption compared to traditional anaerobic fermentation devices, thereby improving the economic efficiency of the equipment operation.

[0029] 5) The equipment for treating organic waste to co-produce hydrogen, organic acid and biochar of the present invention is provided with a distillation tower to separate the organic acid and an outlet to collect the hydrogen. At the same time, the biochar can be directly taken out from the heating furnace, realizing the integrated conversion of organic waste into organic acid, hydrogen and biochar, greatly improving the waste recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic cross-sectional view of the equipment for treating organic waste and co-producing hydrogen, organic acid and biochar according to the present invention.

[0031] The accompanying drawings are as follows:

[0032] 1. Liquid storage tank 2. Dry fermentation reactor

[0033] 3. Sprinkler 4. Leachate collection area

[0034] 5. Fuel storage and combustion area 6. Heating furnace

[0035] 7. pH control system 8. Fractionation tower

[0036] 9. Heat exchange tube 10. Reboiler

[0037] 11. Agitator 12. Screen plate

[0038] 13. Organic acid collection area 14. Liquid inlet pipe

[0039] 15. Liquid outlet 16. Air outlet

[0040] 17. Feed pipe 18. Pump

[0041] 19. Valve 20. Sealing cover DETAILED DESCRIPTION

[0042] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0043] like Figure 1 As shown, an apparatus for treating organic waste and co-producing hydrogen, organic acid and biochar comprises a liquid storage tank 1, a dry fermentation reactor 2, a heating furnace 6 and a fractionating tower 8.

[0044] The dry fermentation reactor 2 includes a sprayer 3 , a leachate collection area 4 , an agitator 11 , a sieve plate 12 , an air outlet 16 , a feed pipe 17 and a sealing cover 20 .

[0045] The dry fermentation reactor 2 is equipped with a sealing cover 20 at the material inlet, a sprayer 3 connected to a liquid outlet pipe 15, and a gas outlet 16 connected to a gas collection device at the top. An agitator 11 is located inside the reactor, and a leachate collection area 4 is located below. A feed pipe 17 connected to a heating furnace 6 is located on the side opposite the material inlet. A screw push rod is installed in the feed pipe 17. The leachate collection area 4 has a sieve plate 12 at the top and a liquid inlet pipe 14 at the bottom.

[0046] The liquid storage tank 1 is arranged on the side of the dry fermentation reactor 2. The interior of the liquid storage tank 1 is divided into a liquid storage area and a pipeline area by the inner wall, and an opening is provided to connect to the liquid inlet pipe 14 through a valve 19. The liquid storage area is used to store buffer and water, and the pipeline area is used to place the liquid inlet pipe-liquid storage tank section pipeline. A pump 18 is provided at the bottom of the placement area. The pump 18 is connected to the leachate collection area 4 and the liquid storage area in the horizontal direction through the liquid inlet pipe 14, and is connected to the heat exchange pipe 9 in the vertical direction through the liquid inlet pipe 14 to exchange heat between the liquid in the pipe and the distillation tower 8.

[0047] The heating furnace 6 is arranged between the dry fermentation reactor 2 and the fractionation tower 8. The bottom of the heating furnace 6 is provided with a fuel storage and combustion area 5, the furnace wall is provided with a pH control system 7, and the upper part is provided with a steam outlet connected to the fractionation tower 8.

[0048] The distillation tower 8 is provided with an organic acid collection area 13 in the tower body, a first outlet connected to the steam outlet of the heating furnace 6 and a second outlet connected to the upper end of the reboiler 10 are provided in the middle and lower part of the tower wall, a third outlet connected to the reflux pipe of the reboiler 10 is provided at the bottom of the tower, and a fourth outlet for exhaust gas discharge is provided at the top of the tower. A heat exchange tube 9 is wound around the outside of the tower wall and connected to the liquid inlet pipe 14 and the liquid outlet pipe 15.

[0049] The dry fermentation reactor 2 is a plug flow reactor. The sludge inoculated with organic waste in the dry fermentation reactor 2 should be heated above 70° C. to remove methanogens.

[0050] The heating temperature of the heating furnace 6 is 200-300°C.

[0051] The inorganic acid used in the pH control system 7 can be phosphoric acid, sulfuric acid and hydrochloric acid. The pH of the fermentation product needs to be adjusted to 2-3 before heating in the heating furnace 6.

[0052] The fractionation tower 8 is a plate tower.

[0053] The reboiler 10 is set at a temperature of 150-180°C.

[0054] The sieve plate 12 is used to carry the material and separate the leachate, and the mesh size depends on the size of the solid material particles in the material.

[0055] The organic acid collection area 13 is used to collect products such as acetic acid and butyric acid. The location and number of the organic acid collection area 13 depend on the final operating conditions of the equipment.

[0056] The liquid outlet pipe 15 is provided with a pH monitoring system and a temperature monitoring system.

[0057] The gas outlet 16 is used for collecting hydrogen.

[0058] In the equipment for co-producing hydrogen, organic acid and biochar, except for the heat exchange pipe 9 and the feed pipe 17, the outer walls of other pipes are provided with insulation layers to reduce heat loss.

[0059] The solid content of the organic waste is 15-50%.

[0060] The working process of the equipment for treating organic waste and co-producing hydrogen, organic acid and biochar is as follows:

[0061] 1. Initial operation of the equipment (generally the first batch of organic waste treatment)

[0062] Before processing the first batch of organic waste, the inoculated sludge is heated at a temperature above 70° C. to remove methanogens, and the treated inoculated sludge is inoculated into the dry fermentation reactor 2 .

[0063] 1.1. Organic Acid and Hydrogen Production Process: The first batch of organic waste is added through the material inlet of dry fermentation reactor 2. The sealing cover 20 is closed, and the agitator 11 is turned on. Dry fermentation reactor 2 begins fermenting the organic waste using the hydrolyzing, organic acid- and hydrogen-producing microorganisms inoculated with the sludge. The leachate produced during the fermentation process flows through the sieve plate 12 into the leachate collection area 4, then through the inlet pipe 14 into the piping area of ​​the liquid storage tank 1. Valve 19 is adjusted to allow the buffer and water in the liquid storage area to flow into the inlet pipe 14, where they merge with the leachate and are pumped by pump 18 to the heat exchange tube 9. The liquid in the heat exchange tube 9 flows through the wall of fractionation tower 8 and into the outlet pipe 15. Pump 18 and valve 19 are regulated to maintain a near-neutral pH and a flow rate within the equipment's set range. Sprinkler 3 is then turned on to spray the organic waste in dry fermentation reactor 2, completing the equipment's liquid phase cycle. This batch fermentation process lasts 4-7 days and is performed at room temperature. Fermentation produces hydrogen and liquid products, including organic acid salts.

[0064] The generated hydrogen is collected through the gas outlet 16 .

[0065] A small portion of the generated liquid phase product passes through the sieve plate 12 and enters the leachate collection area 4 .

[0066] 1.2. Biochar Production Process: After the fermentation time reaches the set time, the screw push rod in the feed pipe 17 is activated to deliver the fermentation product to the heating furnace 6. The pH control system in the heating furnace 6 adjusts the pH of the fermentation product to 2-3, at which point the organic acids in the fermentation product are in a free state. The heating furnace 6 is then started and heated to 200-300°C to evaporate the organic acids. Simultaneously, the fermentation product is pyrolyzed to produce biochar.

[0067] The generated organic acid vapor enters the fractionation tower 8 through the steam outlet and the first outlet at the lower middle portion of the wall of the fractionation tower 8 .

[0068] The produced biochar is taken out from the heating furnace 6 .

[0069] 1.3 Organic Acid Fractionation Process: The temperature of reboiler 10 is set at 150-180°C. Organic acid vapor enters fractionation tower 8 from the lower-middle portion. The heavy components liquefy and sink, entering reboiler 10 through the third opening at the bottom of the tower. The heavy components vaporize in reboiler 10 and enter fractionation tower 8 through the second opening in the lower-middle portion of the tower wall, repeating the cycle.

[0070] The fractionated products are collected in the organic acid collection zone 13. The fractionated products include acetic acid, propionic acid, butyric acid and the like.

[0071] 2. Subsequent operation of the equipment (generally refers to the subsequent treatment of organic waste)

[0072] After the first batch of organic waste fermentation products is delivered to heating furnace 6, the second batch of organic waste is added through the material inlet of dry fermentation reactor 2. Sealing cover 20 is closed, and pump 18 and valve 19 are adjusted to ensure that the pH of the reflux liquid in outlet pipe 15 is near neutral and the temperature and flow rate are within the equipment settings. Dry fermentation reactor 2 then continues fermenting the organic waste. This batch fermentation process lasts 2-3 days at a temperature of 35-85°C. Product collection is the same as in step 1 above.

[0073] 3. The treatment process for subsequent batches of organic waste is the same as step 2 above.

Claims

1. An apparatus for treating organic waste to produce hydrogen, organic acid, and biochar, characterized by: The equipment comprises a liquid storage tank (1), a dry fermentation reactor (2), a heating furnace (6) and a fractionating tower (8); The dry fermentation reactor (2) includes a sprayer (3), a leachate collection area (4), a stirrer (11), a sieve plate (12), an air outlet (16), a feed pipe (17) and a sealing cover (20); The dry fermentation reactor (2) is provided with a sealing cover (20) at the material inlet, a sprayer (3) connected to the liquid outlet pipe (15) and a gas outlet (16) connected to the gas collection device at the top, a stirrer (11) is provided inside, a leachate collection area (4) is provided below, and a feed pipe (17) connected to the heating furnace (6) is provided on the side opposite to the material inlet; a screw push rod is provided in the feed pipe (17); a sieve plate (12) is provided on the top of the leachate collection area (4), and the bottom is connected to the liquid inlet pipe (14); The liquid storage tank (1) is arranged on the side of the dry fermentation reactor (2), and the interior of the liquid storage tank (1) is divided into a liquid storage area and a pipeline area by the inner wall, and is provided with an opening connected to the liquid inlet pipe (14) through a valve (19); the liquid storage area is used to store buffer solution and water, and the pipeline area is used to place the liquid inlet pipe-liquid storage tank section pipeline; a pump (18) is provided at the bottom of the placement area; the pump (18) is connected to the leachate collection area (4) and the liquid storage area in the horizontal direction through the liquid inlet pipe (14), and is connected to the heat exchange pipe (9) in the vertical direction through the liquid inlet pipe (14), so as to exchange heat between the liquid in the pipe and the fractionation tower (8); The heating furnace (6) is arranged between the dry fermentation reactor (2) and the fractionation tower (8), the bottom of the heating furnace (6) is provided with a fuel storage and combustion area (5), the furnace wall is provided with a pH control system (7), and the upper part is provided with a steam outlet connected to the fractionation tower (8); The fractionation tower (8) is provided with an organic acid collection area (13) on its tower body, a first outlet communicating with the steam outlet of the heating furnace (6) and a second outlet communicating with the upper end of the reboiler (10) are provided at the middle and lower part of the tower wall, a third outlet communicating with the reflux pipe of the reboiler (10) is provided at the bottom of the tower, a fourth outlet for exhaust gas discharge is provided at the top of the tower, and a heat exchange pipe (9) is wound around the outside of the tower wall and communicated with the liquid inlet pipe (14) and the liquid outlet pipe (15); The dry fermentation reactor (2) is a plug flow reactor; The sludge inoculated with organic waste in the dry fermentation reactor (2) is heated at a temperature above 70° C. to remove methanogens.

2. The device for treating organic waste to co-produce hydrogen, organic acid and biochar according to claim 1, characterized in that: The heating temperature of the heating furnace (6) is 200-300°C.

3. The device for treating organic waste to co-produce hydrogen, organic acid and biochar according to claim 1, characterized in that: The inorganic acids used in the pH control system (7) are phosphoric acid, sulfuric acid and hydrochloric acid. The pH of the fermentation product needs to be adjusted to 2-3 before heating in the heating furnace (6).

4. The device for treating organic waste to co-produce hydrogen, organic acid and biochar according to claim 1, characterized in that: The fractionation tower (8) is a plate tower.

5. The device for treating organic waste to co-produce hydrogen, organic acid and biochar according to claim 1, characterized in that: The reboiler (10) is set at a temperature of 150-180°C.

6. The device for treating organic waste to co-produce hydrogen, organic acid and biochar according to claim 1, characterized in that: The liquid outlet pipe (15) is provided with a pH monitoring system and a temperature monitoring system.

7. The device for treating organic waste to co-produce hydrogen, organic acid and biochar according to claim 1, characterized in that: In the equipment for co-producing hydrogen, organic acid and biochar, except for the heat exchange pipe (9) and the feed pipe (17), the outer walls of other pipes are provided with a thermal insulation layer to reduce heat loss.

8. The device for treating organic waste to co-produce hydrogen, organic acid and biochar according to claim 1, characterized in that: The solid content of the organic waste is 15-50%.

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