Anaerobic digestion device for distillation wastewater in straw ethanol preparation

Abstract

The utility model discloses an anaerobic digestion device for distillation wastewater in straw ethanol preparation, and belongs to the technical field of wastewater treatment. The system comprises an acidification phase reactor, a sedimentation tank and a methanogenesis phase reactor. According to the anaerobic digestion device for distillation wastewater in straw ethanol preparation, micro-ventilation of the acidizing phase reactor is realized through the air compressor, gas circulation in the acidizing phase reactor is realized through the gas circulating pump, in-situ desulfurization is carried out through coupling of micro-ventilation and gas circulation of the acidizing phase reactor, H2S in produced gas is oxidized into S elementary substance, and the yield of the distilled wastewater is improved. The sludge entering the acidification phase reactor is precipitated, so that inhibition of H2S on acidification phase microorganisms can be avoided, and organic matters in the wastewater are converted into volatile fatty acids; meanwhile, sulfur-containing sludge in an acidizing phase does not enter a subsequent methanogenesis phase, so that H2S inhibition in a methane fermentation process can be reduced, and the wastewater treatment efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of wastewater treatment, in particular to an anaerobic digestion device for distillation wastewater in the preparation of straw ethanol. Background Art

[0002] The production of biofuels and bio-based chemicals using lignocellulosic biomass such as agricultural straw as raw materials can solve the problems of high carbon emissions and environmental pollution caused by the consumption of fossil resources. At present, fermentable sugars are obtained from straw by pretreatment / hydrolysis, and then further converted into biofuels and bio-based chemicals. Among them, the preparation of fermentable sugars based on sulfuric acid-assisted pretreatment / hydrolysis is a relatively common method. However, after the product of this process is distilled, a large amount of high COD and high sulfur distillation wastewater will be generated to be treated.

[0003] Generally speaking, these high-sulfur wastewaters are first treated by anaerobic digestion to produce biogas and then further treated. Under anaerobic conditions, sulfate-reducing bacteria convert sulfate into sulfide (H2S). However, H2S can penetrate the cell membrane and cause inactivation of microbial-related functional enzymes and proteins, and is particularly toxic to sensitive methanogenic archaea, thereby inhibiting the degradation of organic matter and sulfate, causing the anaerobic digestion system to collapse. On the other hand, organic matter in distillation wastewater is very easy to acidify, and traditional anaerobic digestion reactions are difficult to effectively treat such wastewater. Innovative processes are urgently needed to effectively treat distillation wastewater in the preparation of straw ethanol. Utility Model Content

[0004] The utility model aims to provide an anaerobic digestion device for distillation wastewater in the preparation of straw ethanol, so as to solve the problem of difficulty in treating the existing distillation wastewater with high COD and high sulfur content in the preparation of straw ethanol.

[0005] The technical solution of the utility model to solve the above technical problems is as follows:

[0006] The utility model provides an anaerobic digestion device for distillation wastewater in the preparation of straw ethanol, comprising:

[0007] An acidification phase reactor, wherein the acidification phase reactor is used to produce acid from distilled wastewater; a gas circulation pump is connected to the top gas outlet of the acidification phase reactor and the bottom liquid inlet of the acidification phase reactor through a pipeline, and an air compressor is connected to the pipeline of the gas circulation pump; an ORP monitor and a pH detector are installed at the top detection port of the acidification phase reactor;

[0008] a sedimentation tank for performing sedimentation treatment on the treated wastewater from the acidification phase reactor; and

[0009] A methanogenic phase reactor is used to carry out a methanogenic reaction on the upper layer liquid from the sedimentation tank.

[0010] Furthermore, in the anaerobic digestion device for distilled wastewater in the preparation of straw ethanol, the bottom of the acidification phase reactor is filled with fermentation sludge; an agitator is provided at the upper end of the acidification phase reactor; a water distributor is provided at the lower end of the acidification phase reactor, and the water inlet of the water distributor is connected to the bottom water inlet of the acidification phase reactor.

[0011] Furthermore, in the anaerobic digestion device for distillation wastewater in the preparation of straw ethanol, the water distributor includes: a water distribution pipe, and a plurality of water distribution holes are arranged along the circumference of the water distribution pipe.

[0012] Furthermore, in the anaerobic digestion device for distillation wastewater in the preparation of straw ethanol, the side wall water inlet of the sedimentation tank is connected to the side wall liquid outlet of the acidification phase reactor through a pipeline, the side wall water outlet of the sedimentation tank is connected to the bottom water inlet of the methanogenic phase reactor, and the bottom sludge outlet of the sedimentation tank is connected to the bottom inlet of the acidification phase reactor.

[0013] Furthermore, in the anaerobic digestion device for distilling wastewater in the preparation of straw ethanol, the anaerobic digestion device also includes an output gas storage tank, and the air inlet of the output gas storage tank is respectively connected to the output gas outlet of the acidification phase reactor and the output gas outlet of the methanogenic phase reactor through pipelines.

[0014] Furthermore, in the anaerobic digestion device for distillation wastewater in the preparation of straw ethanol, an oxygen content monitoring port for monitoring the oxygen content in the output gas is provided on the connecting pipeline between the acidification phase reactor and the output gas storage tank.

[0015] Furthermore, in the anaerobic digestion device for distillation wastewater in the preparation of straw ethanol, the acidification phase reactor is connected to a pH regulator tank via a pipeline.

[0016] Furthermore, in the anaerobic digestion device for distilled wastewater in the preparation of straw ethanol, the acidification phase reactor is provided with a first controller, and the first controller is communicatively connected with the air compressor and the oxygen content monitoring port respectively.

[0017] Furthermore, in the anaerobic digestion device for distilled wastewater in the preparation of straw ethanol, the acidification phase reactor is provided with a second controller, and the second controller is respectively communicatively connected with the pH detector and the pH regulator tank.

[0018] Furthermore, in the anaerobic digestion device for distillation wastewater in the preparation of straw ethanol, the methanogenic phase reactor includes: a UASB reactor or an IC reactor.

[0019] The utility model has the following beneficial effects:

[0020] 1. The anaerobic digestion device for distillation wastewater in the preparation of straw ethanol provided by the utility model realizes micro-ventilation of the acidification phase reactor through an air compressor, and the air flow rate of the air introduced is 5mL / L / min~15mL / L / min. At the same time, the gas circulation in the acidification phase reactor is realized by a gas circulation pump. The acidification phase reactor couples micro-ventilation and gas circulation to carry out in-situ desulfurization, and the H2S in the output gas is oxidized into S element and enters the sludge precipitation in the acidification phase reactor, which can avoid the inhibition of H2S on the acidification phase microorganisms and convert the organic matter in the wastewater into volatile fatty acids; at the same time, the sulfur-containing sludge in the acidification phase does not enter the subsequent methanogenic phase, so the H2S inhibition in the methane fermentation process can be reduced, thereby improving the wastewater treatment efficiency.

[0021] 2. The anaerobic digestion device for distilled wastewater in the preparation of straw ethanol provided by the utility model uses an ORP monitor to monitor the redox potential of the liquid in the acidification phase reactor, realizes automatic adjustment of the flow rate of air supplied into the reactor, and more effectively reduces the inhibition of H2S on acidification and methanogenesis, thereby promoting the efficiency of methane fermentation; a pH detector is used to detect the pH value of the liquid in the acidification phase reactor to avoid excessive acidification of the methanogenesis phase, resulting in an imbalance between acidogenesis and methanogenesis and reaction failure. In addition, the oxygen content in the output gas is detected through the oxygen content monitoring port to determine whether to stop supplying air. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the embodiments of the present utility model, constitute a part of this application, and do not constitute a limitation of the embodiments of the present utility model. In the drawings:

[0023] Figure 1 It is a schematic structural diagram of the anaerobic digestion device for distillation wastewater in the preparation of straw ethanol in the utility model.

[0024] Marks and corresponding parts names in the attached drawings:

[0025] In the figure: 10-acidification phase reactor, 11-gas circulation pump, 12-air compressor, 13-ORP monitor, 14-pH detector, 15-mixer, 16-water distributor, 161-water distribution pipe, 162-water distribution hole, 17-oxygen content monitoring port, 18-pH regulator tank, 20-sedimentation tank, 30-methane production phase reactor, 40-output gas storage tank, 51-first controller, 52-second controller. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example

[0029] Please refer to Figure 1 The utility model provides an anaerobic digestion device for distillation wastewater in the preparation of straw ethanol, comprising: an acidification phase reactor 10, a sedimentation tank 20 and a methanogenic phase reactor 30 connected in sequence. The distillation wastewater from the preparation of straw ethanol first undergoes an acidogenic reaction in the acidification phase reactor, and the COD in the distillation waste liquid undergoes an acidogenic reaction in the acidification phase to be converted into volatile fatty acids, and an output gas containing hydrogen, methane and carbon dioxide is generated. The treated liquid obtained from the acidification phase reactor is precipitated in a sedimentation tank, and the upper layer of liquid is separated and sent to the methanogenic phase reactor for methanogenic reaction.

[0030] The top gas outlet of the acidification phase reactor 10 and the bottom liquid inlet of the acidification phase reactor are connected to a gas circulation pump 11 through a pipeline, and an air compressor 12 is connected to the pipeline of the gas circulation pump. In the utility model, the acidification phase reactor is micro-ventilated by an air compressor, and the air flow rate of the air introduced is 5mL / L / min to 15mL / L / min. At the same time, the gas circulation in the acidification phase reactor is realized by the gas circulation pump. The acidification phase reactor couples micro-ventilation and gas circulation to perform in-situ desulfurization, and the H2S in the output gas is oxidized into S elemental substance and enters the sludge precipitation in the acidification phase reactor, which can avoid the inhibition of H2S on the acidification phase microorganisms and convert the organic matter in the wastewater into volatile fatty acids; at the same time, the sulfur-containing sludge in the acidification phase does not enter the subsequent methanogenic phase, so the H2S inhibition in the methane fermentation process can be reduced, thereby improving the wastewater treatment efficiency. The top detection port of the acidification phase reactor is equipped with an ORP monitor 13 and a pH detector 14. The ORP monitor is used to monitor the redox potential of the liquid in the acidification phase reactor, and the pH detector is used to detect the pH value of the liquid in the acidification phase reactor to control the appropriate reaction conditions and determine whether to continue to introduce air or whether to adjust the pH value. The critical value monitored by the ORP monitor is -200mv. When the redox potential is greater than or equal to -200mv, the air supply is stopped; the pH value critical value of the pH detector is 5, which can automatically adjust the flow rate of the air supplied to the reactor, more effectively reduce the inhibition of H2S on acidification and methanogenesis, thereby promoting the efficiency of methane fermentation. When the pH value is less than or equal to 5, the pH value needs to be adjusted to avoid excessive acidification of the methanogenic phase, which causes an imbalance between acidogenesis and methanogenesis and leads to reaction failure.

[0031] In some feasible schemes, the bottom of the acidification phase reactor is filled with fermentation sludge, and the fermentation sludge can be the effluent of mesophilic methane fermentation of sludge. The upper end of the acidification phase reactor is provided with a stirrer 15, which is used for stirring during the acid production reaction to improve the reaction efficiency. The lower end of the acidification phase reactor is provided with a water distributor 16, and the water inlet of the water distributor is connected to the bottom water inlet of the acidification phase reactor. The method of distributing water from the bottom is adopted to increase the contact rate between the distilled wastewater and the fermentation sludge and improve the fermentation efficiency.

[0032] In some feasible schemes, the water distributor includes: a water distribution pipe 161, a plurality of water distribution holes 162 are arranged along the circumference of the water distribution pipe, and the water distribution pipe is arranged in the sludge in the acidification phase reactor. The tubular water distribution is used to increase the contact area between the distilled wastewater and the sludge, thereby improving the fermentation efficiency.

[0033] In some feasible schemes, an oxygen content monitoring port 17 for monitoring the oxygen content in the output gas is provided on the connecting pipeline between the acidification phase reactor and the output gas storage tank. The oxygen content in the output gas is detected to determine whether to continue to introduce air. The critical value of the oxygen content monitoring port is 1%. When the oxygen content is greater than or equal to 1%, the air supply is stopped.

[0034] In some feasible schemes, the acidification phase reactor is connected to a pH regulator tank 18 via a pipeline. In this embodiment, the pH regulator tank stores 2 mol / L NaOH solution, which is added to the acidification phase reactor to adjust the pH value to ensure that the pH value is maintained above 5.0.

[0035] In some feasible schemes, the acidification phase reactor is provided with a first controller 51, which is respectively connected to the air compressor and the oxygen content monitoring port. In this embodiment, the first controller is used to determine the start or stop of the air compressor based on the oxygen content detected by the oxygen content monitoring port.

[0036] In some feasible schemes, the acidification phase reactor is provided with a second controller 52, and the second controller is respectively connected to the pH detector and the pH adjuster tank in communication. In this embodiment, the second controller is used to determine whether the pH adjuster tank is opened or closed according to the pH value detected by the pH detector.

[0037] The sedimentation tank 20 is used for sedimentation treatment of the treated wastewater from the acidification phase reactor.

[0038] The side wall water inlet of the sedimentation tank is connected to the side wall liquid outlet of the acidification phase reactor through a pipeline, the side wall water outlet of the sedimentation tank is connected to the bottom water inlet of the methanogenic phase reactor, the bottom sludge outlet of the sedimentation tank is connected to the bottom inlet of the acidification phase reactor, and the sludge in the sedimentation tank is returned to the acidification phase reactor to supplement the sludge concentration for recycling.

[0039] The methanogenic phase reactor 30 is used to carry out a methanogenic reaction on the upper layer liquid from the sedimentation tank.

[0040] The seed sludge of the methanogenic phase is granular sludge from organic wastewater treatment. The upper layer liquid from the sedimentation tank undergoes a methanogenic reaction in a methanogenic phase reactor. The methanogenic phase reactor includes: a UASB reactor or an IC reactor.

[0041] In some feasible schemes, the anaerobic digestion device also includes an output gas storage tank 40, and the gas inlet of the output gas storage tank is connected to the output gas outlet of the acidification phase reactor and the output gas outlet of the methanogenic phase reactor through pipelines. The distilled wastewater undergoes an acidogenic reaction in the acidification phase reactor, and the generated gas is discharged from the output gas outlet of the acidification phase reactor and sent to the output gas storage tank through a pipeline for storage. The supernatant undergoes a methanogenic reaction in the methanogenic phase reactor, and the generated gas is discharged from the output gas outlet of the methanogenic phase reactor and sent to the output gas storage tank through a pipeline for storage.

[0042] Based on the anaerobic digestion device for distillation wastewater in the preparation of straw ethanol provided by the utility model, an anaerobic digestion method is carried out, and the steps are as follows:

[0043] Step S1: sending the distillation wastewater in the preparation of straw ethanol into the acidification phase, and carrying out acid production reaction under the conditions of air introduction and gas circulation in the acidification phase;

[0044] Step S2: Precipitating and stratifying the pretreated wastewater after the acid-generating reaction;

[0045] Step S3: taking the upper clear liquid in the pretreated wastewater after sedimentation and stratification, and sending it to the methanogenic phase for methanogenic reaction.

[0046] The acidification phase is coupled with micro-ventilation (the air flow rate is 5mL / L / min~15mL / L / min) and gas circulation to produce in-situ desulfurization. The H2S in the output gas is oxidized into elemental S and enters the sludge for precipitation, which can avoid the inhibition of H2S on the acidification phase microorganisms and convert the organic matter in the wastewater into volatile fatty acids. At the same time, the sulfur-containing sludge in the acidification phase does not enter the subsequent methanogenic phase, thereby reducing the H2S inhibition in the methane fermentation process.

[0047] The COD in the distillation waste liquid undergoes an acidification reaction in the acidification phase and is converted into volatile fatty acids, and produces output gas containing oxygen, hydrogen, methane, and carbon dioxide, providing an easily usable substrate for biogas production in the subsequent methanogenic phase, thereby avoiding excessive acidification of the methanogenic phase, resulting in an imbalance between acidogenesis and methanogenesis and leading to reaction failure.

[0048] By controlling the redox potential of the liquid in the acidification phase at -300mv to -200mv, the flow rate of air supplied to the reactor can be automatically adjusted based on this, which can more effectively reduce the inhibition of H2S on acidification and methanogenesis, thereby promoting the efficiency of methane fermentation.

[0049] Furthermore, the temperature for acid production is 35°C to 37°C, which may be 35°C, 35.3°C, 35.5°C, 35.7°C, 36°C, 36.3°C, 36.5°C, 36.7°C, 37°C, etc.; or 53°C to 55°C, which may be 53°C, 53.3°C, 53.5°C, 53.7°C, 54°C, 54.3°C, 54.5°C, 54.7°C, 55°C, etc., but is not limited to the listed values, and other values ​​not listed within the range are equally applicable.

[0050] Further, the acid-generating reaction comprises:

[0051] The flow rate of the introduced air is 5 mL / L / min to 15 mL / L / min, and can be 5 mL / L / min, 7 mL / L / min, 10 mL / L / min, 11 mL / L / min, 12 mL / L / min, 13 mL / L / min, 14 mL / L / min, 15 mL / L / min, etc., but is not limited to the listed values, and other values ​​not listed within the range are equally applicable.

[0052] The flow rate of gas circulation in the acidifying phase is 0.5L / L / min to 4L / L / min, and can be 0.5L / L / min, 0.7L / L / min, 1L / L / min, 1.5L / L / min, 2L / L / min, 2.5L / L / min, 3L / L / min, 3.5L / L / min, 4L / L / min, etc., but is not limited to the listed values, and other values ​​not listed within the range are equally applicable.

[0053] And / or, the stirring speed is 60 rpm to 100 rpm, and can be 60 rpm, 65 rpm, 70 rpm, 75 rpm, 80 rpm, 85 rpm, 90 rpm, 95 rpm, 100 rpm, etc., but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0054] And / or, the liquid circulation volume is 50L / L / d to 100L / L / d, and can be 50L / L / d, 55L / L / d, 60L / L / d, 67L / L / d, 75L / L / d, 85L / L / d, 95L / L / d, 100L / L / d, etc., but is not limited to the listed values, and other unlisted values ​​within the range are equally applicable.

[0055] and / or, the acidification treatment adopts a daily loading and unloading method;

[0056] And / or, the hydraulic retention time is 1 day to 4 days, and can be 1 day, 2 days, 3 days, 4 days, etc., but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0057] Furthermore, the acid-generating reaction also includes: the redox potential of the liquid in the acidified phase is -300mv to -200mv, which can be -300mv, -290mv, -280mv, -270mv, -260mv, -250mv, -240mv, -230mv, -220mv, -210mv, -200mv, etc., but is not limited to the listed values, and other values ​​not listed in this range are also applicable.

[0058] And / or, the pH value of the liquid in the acidified phase is 5-12.

[0059] Furthermore, in the anaerobic digestion method, the determination of stopping the continued introduction of air is:

[0060] When the redox potential of the liquid in the acidified phase is greater than or equal to -200mv;

[0061] and / or, when the oxygen content in the output gas of the acidification phase is greater than or equal to 1%.

[0062] Furthermore, the sedimentation time of the pretreated wastewater is 60 min to 120 min, which can be 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, etc., but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0063] Furthermore, the liquid supply flow rate of the supernatant entering the methanogenic phase of 0.05L / L / d to 0.1L / L / d can be 0.05L / L / d, 0.06L / L / d, 0.07L / L / d, 0.08L / L / d, 0.09L / L / d, 0.1L / L / d, etc., but is not limited to the listed values, and other unlisted values ​​within the range are equally applicable.

[0064] It should be noted that the unit is mL / L / min, which represents the fluid volume per minute within a unit length (mL).

[0065] Unit: L / L / min, represents the fluid volume per unit length (L) per minute.

[0066] Unit: L / L / d, represents the fluid volume per unit length (L) per day.

[0067] Examples

[0068] The acidification phase reaction used a completely stirred tank (CSTR) reactor (total volume and effective volume were 1.0 L and 0.8 L, respectively). The methanogenic phase used an IC reactor or a UASB reactor (total volume and effective volume were 1.0 L and 0.8 L, respectively).

[0069] A complete stirring reactor (CSTR) used in the acidification phase, an IC reactor or a UASB reactor used in the acidification phase are combined as a two-phase reactor, and a complete stirring reactor (CSTR) used in the acidification phase is used as a single reactor for acidification reaction. In the complete stirring reactor (CSTR), the gas from the acidification phase is pumped into the water storage bottle through a gas circulation pump (1.0L / L / min), and the gas after water washing returns to the reactor for the next cycle. While the gas is circulating, a trace amount of air (10ml / L / min) is supplied to the gas path. The reactor temperature is maintained at 37°C, the stirring speed is 80rpm, the hydraulic retention time is 2 days, the liquid circulation volume is 90L / L / d, and the redox potential of the liquid is -250mv.

[0070] The distilled wastewater treated in the completely stirred tank (CSTR) reactor is precipitated for 80 minutes, and the supernatant enters the IC reactor or UASB reactor at a liquid supply rate of 0.1L / L / d for methanogenesis, which usually takes 10 days.

[0071] Take the distillation wastewater in the preparation of straw ethanol as an example. The COD concentration in the wastewater is 6290 mg / L, SO4 2- The concentration was 2300 mg / L. The wastewater was treated by anaerobic digestion using the two-phase configuration reactor (coupled micro-ventilation + gas circulation system) in the test example. The reactor achieved stable operation for 90 days, with the COD removal efficiency fluctuating in the range of about 90-92.7%, and the stable methane yield was 301 ml / g-COD.

[0072] The above specific implementation methods further illustrate the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above are only specific implementation methods of the utility model and are not used to limit the protection scope of the utility model. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. An anaerobic digestion device for distillation wastewater in straw ethanol production, characterized in that: include: An acidification phase reactor, wherein the acidification phase reactor is used to produce acid from distilled wastewater; a gas circulation pump is connected to the top gas outlet of the acidification phase reactor and the bottom liquid inlet of the acidification phase reactor through a pipeline, and an air compressor is connected to the pipeline of the gas circulation pump; an ORP monitor and a pH detector are installed at the top detection port of the acidification phase reactor; a sedimentation tank, the sedimentation tank being used for sedimentation treatment of the treated wastewater from the acidification phase reactor; and The methanogenic phase reactor is used for carrying out a methanogenic reaction on the upper layer liquid from the sedimentation tank.

2. The anaerobic digestion device for distilled wastewater in straw ethanol preparation according to claim 1, characterized in that: The bottom of the acidification phase reactor is filled with fermented sludge; the upper end of the acidification phase reactor is provided with a stirrer; the lower end of the acidification phase reactor is provided with a water distributor, and the water inlet of the water distributor is connected to the bottom water inlet of the acidification phase reactor.

3. The anaerobic digestion device for distilled wastewater in straw ethanol preparation according to claim 2, characterized in that: The water distributor comprises a water distribution pipe, and a plurality of water distribution holes are arranged along the circumference of the water distribution pipe.

4. The anaerobic digestion device for distilled wastewater in straw ethanol preparation according to claim 1, characterized in that: The side wall water inlet of the sedimentation tank is connected to the side wall liquid outlet of the acidification phase reactor through a pipeline, the side wall water outlet of the sedimentation tank is connected to the bottom water inlet of the methanogenic phase reactor, and the bottom sludge outlet of the sedimentation tank is connected to the bottom inlet of the acidification phase reactor.

5. The anaerobic digestion device for distillation wastewater in straw ethanol preparation according to claim 1, characterized in that: The anaerobic digestion device further comprises an output gas storage tank, the gas inlet of which is respectively connected to the output gas outlet of the acidification phase reactor and the output gas outlet of the methanogenic phase reactor through pipelines.

6. The anaerobic digestion device for distillation wastewater in straw ethanol preparation according to claim 5, characterized in that: An oxygen content monitoring port for monitoring the oxygen content in the output gas is provided on the connecting pipeline between the acidification phase reactor and the output gas storage tank.

7. The anaerobic digestion device for distillation wastewater in straw ethanol production according to claim 1, characterized in that: The acidification phase reactor is connected to a pH regulator tank via a pipeline.

8. The anaerobic digestion device for distillation wastewater in straw ethanol preparation according to claim 6, characterized in that: The acidification phase reactor is provided with a first controller, and the first controller is respectively connected to the air compressor and the oxygen content monitoring port for communication.

9. The anaerobic digestion device for distillation wastewater in straw ethanol production according to claim 7, characterized in that: The acidification phase reactor is provided with a second controller, and the second controller is respectively connected to the pH detector and the pH regulator tank for communication.

10. The anaerobic digestion device for distillation wastewater in straw ethanol production according to claim 1, characterized in that: The methanogenic phase reactor includes: a UASB reactor or an IC reactor.

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