CN110804454B - Method for recycling wood vinegar - Google Patents

Method for recycling wood vinegar Download PDF

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CN110804454B
CN110804454B CN201911215842.8A CN201911215842A CN110804454B CN 110804454 B CN110804454 B CN 110804454B CN 201911215842 A CN201911215842 A CN 201911215842A CN 110804454 B CN110804454 B CN 110804454B
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carbon
anaerobic
electrolysis
wood vinegar
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CN110804454A (en
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李岩
华栋梁
范庆文
许海朋
赵玉晓
陈雷
赵保峰
金付强
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Energy Research Institute of Shandong Academy of Sciences
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10C—WORKING-UP PITCH, ASPHALT, BITUMEN, TAR; PYROLIGNEOUS ACID
    • C10C5/00—Production of pyroligneous acid distillation of wood, dry distillation of organic waste
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
    • C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
    • C10L3/10—Working-up natural gas or synthetic natural gas
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E50/00—Technologies for the production of fuel of non-fossil origin
    • Y02E50/10—Biofuels, e.g. bio-diesel
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E50/00—Technologies for the production of fuel of non-fossil origin
    • Y02E50/30—Fuel from waste, e.g. synthetic alcohol or diesel

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  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Materials Engineering (AREA)
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  • Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)
  • Preparation Of Compounds By Using Micro-Organisms (AREA)

Abstract

A method for recycling pyroligneous liquor comprises the following steps: (1) preparing wood vinegar; (2) pre-separating and removing oil; (3) diluting; (4) electrolyzing wood vinegar with three-dimensional iron carbon; (5) anaerobic fermentation methane production comprises anaerobic granular sludge domestication and an upflow anaerobic sludge bed as a methane production reaction device, wherein the domesticated anaerobic granular sludge is placed in the methane production reaction device, and the domesticated anaerobic granular sludge accounts for about half of the total volume of the methane production reaction device after being added and placed still; and (3) adjusting the pH of the upper liquid part to 7.0 after electrolysis, then feeding the upper liquid part into UASB (upflow anaerobic sludge blanket), and generating acetic acid, hydrogen and carbon dioxide by organic matters in a methanogenic reactor under the action of acid-producing bacteria, and then converting the acetic acid, the hydrogen and the carbon dioxide into methane by the methanogenic bacteria.

Description

Method for recycling wood vinegar
Technical Field
The invention relates to a technology for utilizing wood vinegar, in particular to a method for recycling wood vinegar.
Background
The pyroligneous liquor is an organic liquid component obtained by condensing, recovering and separating gas generated in the biomass pyrolysis carbonization process. The components are complex, mainly acid, phenol, nitrogen-containing hybrid compounds, ketone and aldehyde organic matters, and also contain partial alcohol, ester, amine substances and the like. According to the functional characteristics of the components, the wood vinegar is mainly used as a plant growth promoter, a bacteriostatic agent, compost, a feed additive, a food additive and the like at present, the development of the wood vinegar utilization way has important significance for improving the added value of the wood vinegar, and relevant reports of preparing biogas by the wood vinegar are not found through consulting documents, patents and other data.
Disclosure of Invention
The invention aims to provide high-efficiency humanization of wood vinegarThe method is used for preparing the biogas by intensively treating the pyroligneous liquor wastewater by combining a three-dimensional iron-carbon electrolysis technology and anaerobic fermentation. Aiming at the characteristic of complex components in the pyroligneous liquor, the three-dimensional iron-carbon electrolysis technology is adopted to decompose toxic substances such as phenols, pyridines and the like, the technology mainly adopts granular activated carbon with large specific surface area and zero-valent iron as granular electrodes, can provide more active reaction sites to improve the mass transfer rate, and micro electrolytic cells formed by a plurality of granular electrodes are uniformly dispersed in a reaction system through aeration and stirring actions to accelerate the degradation of the toxic substances. The main principle is the anodic generation of Fe2+，Fe3+And H generated at the cathode2O2The organic matter is oxidized by direct or indirect means. The biochemical utilization of the treated pyroligneous liquor is obviously improved, and the methane yield can be obviously improved under the action of anaerobic microorganisms.
In order to realize the purpose, the invention adopts the technical scheme that: a method for recycling pyroligneous liquor comprises the following steps:
(1) preparation of pyroligneous liquor
The peanut shells are used as raw materials, flue gas generated in the production of biomass carbon by the thermal cracking method is condensed to collect flue gas condensate of 100-450 ℃, and the flue gas condensate is stood for later use.
(2) Pre-separating and removing oil.
The pyroligneous liquor was kept in a refrigerator at 4 ℃ for 24 hours, and the upper oily matter was separated and removed. The concentration of acetic acid in the separated water phase is 53000 mg/L, COD is 110000 mg COD/L, and pH is 3.5.
(3) And (6) diluting.
Diluting the wood vinegar liquid to different concentrations (4000 mg COD/L, 6000 mg COD/L and 8000 mg COD/L), inspecting the methane production condition of the wood vinegar liquid under different concentrations, determining the gas production inhibition effect and corresponding concentration according to the fermentation result, and taking the concentration as the research object of the electrolysis experiment.
(4) Three-dimensional iron-carbon electrolysis treatment of wood vinegar.
The three-dimensional electrolysis system selects a stainless steel electrode as an anode material, a graphite electrode as a cathode material and wooden columnar activated carbon and iron powder as diffusion electrodes. The direct current voltage stabilizer provides a stable direct current power supply for the electrolysis system. Adding the wood vinegar with the concentration inhibited in the step (2) into a reaction tank, controlling the electrolysis degree by controlling parameters such as voltage, electrolysis time, iron-carbon ratio and the like when treating the wood vinegar by using a three-dimensional iron-carbon electrolysis technology, wherein the voltage range is 0-20V, the treatment time is 30-120min, the iron-carbon addition amount is 80-120 g/L, and the iron-carbon ratio is 1:2 to 2: 1. after the pretreatment of the electrolysis system, standing to remove the active carbon and the residual iron powder, and taking the upper liquid for later use.
(5) Anaerobic fermentation for producing methane
a, anaerobic granular sludge domestication: the inoculum was anaerobic granular sludge with a total solid matter content of 9.92% and volatile solid matter content of 72.5%. In order to better improve the utilization capacity of the anaerobic granular sludge to organic acid, the prepared acetic acid solution is adopted to domesticate the anaerobic granular sludge to obtain acid-producing bacteria and methanogenic bacteria with higher reaction activity.
b, adopting an up-flow anaerobic sludge bed (UASB) as a methanogenesis reaction device, placing the domesticated anaerobic granular sludge into the methanogenesis reaction device, and standing the domesticated anaerobic granular sludge to be about half of the total volume of the methanogenesis reaction device. And (3) electrolyzing the upper layer liquid part to mainly obtain short carbon chain organic acids such as acetic acid, propionic acid, butyric acid and the like and generated small molecular organic matters, adjusting the pH of the liquid to 7.0, then feeding the liquid into UASB (upflow anaerobic sludge blanket), and generating acetic acid, hydrogen and carbon dioxide by the organic matters in a methane-generating reaction device under the action of acid-producing bacteria, and then converting the acetic acid, the hydrogen and the carbon dioxide into methane by the methane-producing bacteria.
The method is particularly characterized in that effluent water in the methanogenesis reaction device is used for adjusting and diluting the pyroligneous liquor, and the concentration of organic matters in the pyroligneous liquor is changed through dilution, so that the UASB feeding load is adjusted.
The anaerobic granular sludge domestication is characterized in that the sludge is domesticated by adopting a prepared acetic acid solution, and the formula is as follows: sodium acetate is used as carbon source (2000 mg COD/L), and NH is respectively used as nitrogen source and phosphorus source4Cl and KH2PO4Provided that the COD is N: P =200:5:1, and the other trace element formulations are as shown in the table below. Other nutrient elements (mg/L) for domesticating the granular sludge are added according to the proportion of 1 mL/g COD trace elements.
Figure 100002_DEST_PATH_IMAGE001
The diameter of the wooden columnar activated carbon is 1.5 mm, the packing density is less than or equal to 550 g/L, and the iodine value is more than or equal to 600 mg/g. The grain sizes of the high-purity iron powder with different specifications are 40 meshes, 100 meshes and 200 meshes respectively.
The invention has the beneficial effects that: (1) the utilization value of the existing wood vinegar is low, methane is not found in the wood vinegar through direct anaerobic fermentation without treatment, and the inhibition or toxicity effect of partial organic matters in the wood vinegar on microorganisms is proved. According to the invention, the three-dimensional iron-carbon electrolysis technology is coupled with anaerobic fermentation to carry out energy utilization on the wood vinegar liquid, so that clean gas fuel-methane can be obtained, and the application approach is widened while the existing application value of the wood vinegar liquid is obviously improved. (2) The COD removal rate is only 11%, the biodegradability of the waste water is improved by utilizing a substrate directional regulation and control technology, and the energy contained in the pyroligneous liquor is effectively recovered. (3) The upper layer liquid obtained by standing after three-dimensional electrolytic treatment contains Fe2+And a small amount of suspended C powder, Fe3+The active carbon has a promoting effect on the activity of methanogens, can be used as a carrier for directly transferring electrons between inoculations to improve the conversion efficiency and the gas production rate of acid, and in addition, the adsorption performance of the active carbon can act on a small amount of residual toxic substances to reduce the negative effect on microorganisms, and compared with a control group which is not subjected to electrolysis treatment, the gas production rate can be improved by 110 percent at most. (4) After the pyroligneous is treated by three-dimensional iron-carbon electrolysis, the pH value is increased from initial 3.5 to about 6.5, and compared with the direct fermentation of the pyroligneous, the alkali amount required by the initial pH adjustment in the anaerobic fermentation process can be reduced. (5) The UASB-treated pyroligneous liquor can be used as dilution water to reduce the addition of external water and to perform secondary treatment on the organic matter which is not completely degradedAnd (3) treating to improve the degradation degree and the gas production rate of the substrate.
Detailed Description
Example 1: the anaerobic fermentation experiment of the pyroligneous liquor with different concentrations comprises the following steps:
(1) preparation of pyroligneous liquor
The peanut shell is used as a raw material, smoke generated after biochar production through 550 ℃ thermal cracking is condensed, 100-450 ℃ smoke condensate is collected, and the condensate is stood for later use.
(2) Pre-separating and removing oil.
The pyroligneous liquor was kept in a refrigerator at 4 ℃ for 24 hours, and the upper oily matter was separated and removed. The pyroligneous liquor for experiments is a condensed liquid phase product of peanut shell pyrolysis gas of a certain chemical plant, and mainly contains acetic acid, propionic acid, butyric acid, phenol, pyridine and the like. Wherein the concentration of acetic acid is 53000 mg/L, and COD is 110000 mg/L.
(3) And (6) diluting.
Due to the high concentration of acetic acid in the wood vinegar liquid and the existence of toxic substances, the direct anaerobic fermentation fails to produce gas due to the high load and the inhibition effect, so the wood vinegar liquid needs to be diluted. The concentration of the pyroligneous liquor was diluted to 4000 mg COD/L, 6000 mg COD/L and 8000 mg COD/L, respectively, by adding water.
(4) And (5) anaerobic fermentation.
400 mL of pyroligneous liquor with different concentrations are put into an anaerobic reaction bottle. 140 g of granular sludge is inoculated into the anaerobic bottle to ensure that the anaerobic reaction system is more than 20 g VS/L. Adding trace elements according to the COD concentration of the solution, and respectively adding NH to the nitrogen source and the phosphorus source4Cl and K2HPO4The additive is added according to the mass ratio of COD to N to P =200 to 5 to 1. The pH was adjusted to around 7 with NaOH. Blowing off the top space with nitrogen for 3min, adding rubber pad, sealing to ensure a sealed anaerobic environment in the reaction bottle, fermenting at constant temperature in a 38 ℃ water bath, and shaking once every 5h to make the substrate and granular sludge uniformly contact. Biogas is collected daily and the volume and composition of the gas is measured and the pH in the batch reactor is monitored to ensure a suitable pH range.
As a result, the wood vinegar concentration is 4000 mg COD/L, 6000 mg COD/L and 8000 mg COD/L, the cumulative methane yield is 127.1 mL/gCOD, 109.6 mL/gCOD and 34.9 mL/gCOD respectively, and the inhibition effect is obvious under the concentration condition.
Example 2: a method for recycling pyroligneous liquor comprises the following steps:
(1) preparation of pyroligneous liquor
Peanut shells are used as raw materials, smoke generated after biochar is produced by condensing through thermal cracking at 550 ℃, smoke condensate at the temperature of 100-450 ℃ is collected, and standing is carried out to obtain a water phase for later use.
(2) Pre-separating and removing oil.
The pyroligneous liquor for experiments is a water-phase product obtained by condensing pyrolysis gas of peanut shells, and mainly contains organic matters such as acetic acid, propionic acid, butyric acid, phenol, pyridine and the like. The pyroligneous liquor was kept in a refrigerator at 4 ℃ for 24 hours, and the upper oily matter was separated and removed. The concentration of acetic acid in the separated water phase is 53000 mg/L, COD is 110000 mg COD/L, and pH is 3.5.
(3) And (6) diluting.
The gas production of the wood vinegar liquid under different concentration conditions in example 1 was inhibited to different degrees in the range studied, so that the wood vinegar liquid with the lowest concentration of 4000 mg COD/L was selected as the subject of the electrolytic treatment, and the change of the gas production after the treatment was examined.
(4) Three-dimensional iron-carbon electrolysis treatment of wood vinegar.
Adding the pyroligneous diluted to 4000 mg COD/L into a reaction tank, and adding uniformly mixed wood columnar activated carbon and iron powder into the reaction tank to serve as a particle electrode. The iron-carbon filler is added at 100 g/L, Fe/C =1: 2. The particle sizes of the iron powder for experiments are 40 meshes, 100 meshes and 200 meshes respectively. The anode material is a stainless steel electrode, and the cathode material is a graphite electrode. The direct current voltage stabilizer provides a stable direct current power supply for the electrolysis system. Adding 4000 mg COD/L of pyroligneous liquor into a reaction tank, controlling the voltage to be 5V, and electrolyzing the pyroligneous liquor wastewater for 60 min. After pretreatment by an electrolysis system, standing to remove the active carbon and the residual iron powder, and taking the upper liquid for later use.
The diameter of the wooden columnar activated carbon is 1.5 mm, the packing density is less than or equal to 550 g/L, and the iodine value is more than or equal to 600 mg/g. The grain sizes of the high-purity iron powder with different specifications are 40 meshes, 100 meshes and 200 meshes respectively.
(5) Anaerobic fermentation is carried out to produce methane.
a, anaerobic granular sludge domestication:
in order to better improve the utilization capacity of the granular sludge to organic acid, the prepared acetic acid solution is adopted to acclimate the sludge, and the formula is as follows: sodium acetate is used as carbon source (2000 mg COD/L), and NH is respectively used as nitrogen source and phosphorus source4Cl and KH2PO4Provided that the COD is N: P =200:5:1, and the other trace element formulations are as shown in the table below.
Other nutrient elements (mg/L) for domesticating the granular sludge are added according to the proportion of 1 mL/g COD trace elements.
Figure 674984DEST_PATH_IMAGE001
And b, diluting the liquid in the upper layer of the step (3) to a proper load, adjusting the pH value of the liquid, then feeding the diluted liquid into an Upflow Anaerobic Sludge Blanket (UASB) of a methanogenesis reaction device, and allowing the organic acid such as propionic acid and butyric acid in the methanogenesis reaction device to generate acetic acid, hydrogen and carbon dioxide under the action of acid-producing bacteria and then converting the acetic acid, hydrogen and carbon dioxide into methane by the methanogenesis bacteria.
In the step (4), the inoculum adopts anaerobic granular sludge, the total solid matter content of the anaerobic granular sludge is 9.92%, and the volatile solid matter content of the anaerobic granular sludge is 72.5%.
In the step (4), the concentration of organic matters in the pyroligneous liquor is changed by dilution, so that the feed load of the UASB is adjusted.
In the step (4), the pH value of the pyroligneous liquor is required to be adjusted to 7.0 to meet the requirement of pH value before entering UASB after three-dimensional iron-carbon electrolysis.
The effluent water in the methanogenesis reaction device is used for adjusting and diluting the pyroligneous liquor.
After the pretreatment of iron powder (40 meshes, 100 meshes and 200 meshes) with different particle sizes by a three-dimensional electrolysis technology, the cumulative methane yield respectively reaches 173.1 mL/gCOD, 183.1 mL/g COD and 214.7 mL/g COD, which are respectively improved by 36.2%, 43.3% and 70.5% compared with the control group without electrolysis treatment when the load is 4000 mg COD/L in example 1.
Example 3: the same parts of this embodiment as embodiment 2 will not be described again, but the differences are: comparison of gas evolution under different Filler amount electrolytic conditions
The operating conditions of micro-electrolysis in example 2 were changed to 80 g/L filler and 100 mesh iron powder. The rest of the operation was the same as in example 2, and the result showed that the methane yield reached 163.5 mL/g COD.
Example 4: the same parts of this embodiment as embodiment 2 will not be described again, but the differences are: comparison of gas evolution under different Filler amount electrolytic conditions
The operating conditions of micro-electrolysis in example 2 were changed to an amount of filler added of 120 g/L and a mesh number of iron powder of 100 mesh. The rest of the operation was the same as in example 2, and the result showed that the methane yield reached 159.7 mL/g COD.
Example 5: the same parts of this embodiment as embodiment 2 will not be described again, but the differences are: comparison of gas evolution under different Fe/C ratio electrolysis conditions
The operating conditions for the microelectrolysis in example 2 were changed to Fe: c =1:1, and the mesh number of the iron powder is 100 meshes. The rest of the operation was the same as in example 2, and the result showed that the methane yield reached 163.6 mL/g COD.
Example 6: the same parts of this embodiment as embodiment 2 will not be described again, but the differences are: comparison of gas evolution under different Fe/C ratio electrolysis conditions
The operating conditions for the microelectrolysis in example 2 were changed to Fe: c =2:1, and the mesh number of the iron powder is 100 meshes. The rest of the operation was the same as in example 2, and the result showed that the methane yield was only 141.8 mL/g COD.
Example 7: the same parts of this embodiment as embodiment 2 will not be described again, but the differences are: comparison of gas evolution under different Voltage Electrolysis conditions
The operating conditions of the micro-electrolysis in example 2 were changed to a voltage of 3V, and the number of iron powder was 100 mesh. The remaining operating conditions were the same as in example 2. The results showed that the methane yield was 156.6 mL/g COD.
Example 8: the same parts of this embodiment as embodiment 2 will not be described again, but the differences are: comparison of gas evolution under different Voltage Electrolysis conditions
The operating conditions of the micro-electrolysis in example 2 were changed to a voltage of 10V, and the number of iron powder was 100 mesh. The remaining operating conditions were the same as in example 2. The results showed that the methane yield was 178.7 mL/g COD.
Example 9: the same parts of this embodiment as embodiment 2 will not be described again, but the differences are: comparison of gas evolution under different Voltage Electrolysis conditions
The operating conditions of the micro-electrolysis in example 2 were changed to a voltage of 20V, and the number of iron powder was 100 mesh. The remaining operating conditions were the same as in example 2, and the results showed a methane yield of 150.4 mL/g COD, which was a 51.4% reduction compared to example 2.
Example 10: the same parts of this embodiment as embodiment 2 will not be described again, but the differences are: comparison of gas evolution at different electrolysis times
The micro-electrolysis operation condition in the example 2 is changed into micro-electrolysis treatment time of 30 min, and the mesh number of the iron powder is 100 meshes. The rest of the operation was the same as in example 2, and the result showed that the methane yield was 267.4 mL/g COD.
Example 11: the same parts of this embodiment as embodiment 2 will not be described again, but the differences are: comparison of gas evolution at different electrolysis times
The micro-electrolysis operation condition in the example 2 is changed into the micro-electrolysis treatment time of 90 min, and the mesh number of the iron powder is 100 meshes. The rest of the operation was the same as in example 2, and the results showed that the yield of methane was as high as 163.1 mL/g COD.
Example 12: the same parts of this embodiment as embodiment 2 will not be described again, but the differences are: comparison of gas evolution at different electrolysis times
The three-dimensional electrolysis operation condition in example 2 was changed to 120min, and the mesh number of iron powder was 100 mesh. The rest of the operation was the same as in example 2, and the result showed that the methane yield was 149.6 mL/g COD,
from examples 2-12, it can be seen that the methane yield exhibited different results under different electrolysis conditions, because under certain conditions, the degradation degree of large and small molecular substances was high, and more substances were converted into carbon dioxide and water, in which case the methane yield was low, and by adjusting the appropriate electrolysis parameters, the degradation degree of substances could be effectively controlled, thereby increasing the methane yield.
Example 13: the same parts of this embodiment as embodiment 2 will not be described again, but the differences are: experiment of promoting effect of Fe and C on anaerobic fermentation
The particle size of the iron powder is selected to be 100 meshes, and the rest of the electrolysis and fermentation operation steps are the same as those of the example 2, and the difference is that: the liquid obtained after the three-dimensional electrolytic pretreatment in the embodiment 2 is subjected to carbon removal and iron removal treatment, and the method comprises the following specific steps: (1) the insoluble carbon was removed by centrifugation at 10000 rpm. (2) The precipitate was removed by centrifugation after adjusting the pH to 10. The fermentation gas production result shows that the accumulated methane yield is 147.8 mL/g COD, which is reduced by 19.3% compared with the same condition of 100-mesh iron powder electrolytic treatment in the example 2.
Example 14: the three-dimensional iron-carbon electrolysis technology improves the pH value of the solution.
(1) The procedure of example 2 (1) and (2) was followed.
(2) Three-dimensional iron-carbon electrolysis wood vinegar.
Uniformly mixed wood columnar activated carbon and iron powder are added into the reaction tank to be used as diffusion electrodes. The filler is added according to 100 g/L, and the Fe/C ratio is 1: 2. The anode material is a stainless steel electrode, and the cathode material is a graphite electrode. Adding the diluted wood vinegar to be treated into a reaction tank, and electrolyzing the wood vinegar wastewater by adopting 3V voltage for 60 min. After pretreatment by an electrolysis system, standing to remove the activated carbon and the residual iron powder, taking the upper layer liquid, measuring the pH value, and increasing the pH value of the solution to 6.56 after electrolysis.
Example 15: comparison of three-dimensional iron-carbon Electrolysis techniques
Through literature research, under the optimal condition, the COD removal rate reaches 72.3 percent in the berberine waste water treated by the three-dimensional electrode-iron carbon micro-electrolysis combined process, most of COD is removed, and the degradation degree of macromolecular substances is not controlled. If the phenolic compounds and pyridine compounds in the pyroligneous liquor are completely degraded, the final product is CO2And H2O, COD meetingThe COD removal rate before and after electrolysis is only 11% under the conditions that the voltage is 3V, the filler is 100 g/L, Fe/C is 1:2 and the electrolysis time is 60 min through the implementation of controllable three-dimensional electrolysis, the treatment effect is greatly different from that in the literature, the removal rate can indicate that macromolecular substances are not fully degraded, the degradation degree is effectively controlled, the methane yield can reach 267.4 mL/g COD at the highest from the aspect of gas production rate, and the loss of substances caused by electrolysis is less.

Claims (4)

1. A method for recycling pyroligneous acid is characterized by comprising the following steps:
(1) preparing wood vinegar;
taking peanut shells as raw materials, condensing the flue gas produced by biomass carbon by a thermal cracking method, collecting 100-450 ℃ flue gas condensate, and standing for later use;
(2) pre-separating and removing oil;
putting the wood vinegar liquid in a refrigerator at 4 ℃ for 24 hours, and separating to remove the upper oily matter; the concentration of acetic acid in the separated water phase is 53000 mg/L, COD is 110000 mg COD/L, and pH is 3.5;
(3) diluting;
diluting the wood vinegar to different concentrations of 4000 mg COD/L, 6000 mg COD/L and 8000 mg COD/L, inspecting the methane production condition of the wood vinegar under different concentrations, determining the gas production inhibition effect and corresponding concentration according to the fermentation result, and taking the concentration as the research object of the electrolysis experiment;
(4) electrolyzing wood vinegar with three-dimensional iron carbon;
the three-dimensional electrolysis system selects a stainless steel electrode as an anode material, a graphite electrode as a cathode material, and wooden columnar activated carbon and iron powder as diffusion electrodes; the direct current voltage stabilizer provides a stable direct current power supply for the electrolysis system; adding the diluted pyroligneous liquor to be treated into a reaction tank, controlling the electrolysis degree by controlling the voltage, the electrolysis time and the iron-carbon ratio when treating the pyroligneous liquor by the three-dimensional iron-carbon electrolysis technology, wherein the voltage range is 0-20V, the treatment time is 30-120min, the iron-carbon addition is 80-120 g/L, and the iron-carbon ratio is 1:2 to 2: 1; after pretreatment of an electrolysis system, standing to remove active carbon and residual iron powder, and taking upper-layer liquid for later use;
(5) anaerobic fermentation for producing methane
a, anaerobic granular sludge domestication: the inoculum adopts anaerobic granular sludge, the total solid matter content of which is 9.92 percent, and the volatile solid matter content of which is 72.5 percent; in order to better improve the utilization capacity of the anaerobic granular sludge to organic acid, the anaerobic granular sludge is acclimated by adopting an acetic acid solution to obtain acid-producing bacteria and methanogenic bacteria;
b, taking an upflow anaerobic sludge blanket as a methanogenesis reaction device, placing the domesticated anaerobic granular sludge into the methanogenesis reaction device, and standing the domesticated anaerobic granular sludge to be about half of the total volume of the methanogenesis reaction device; and (3) adjusting the pH of the liquid to 7.0 after the liquid part at the upper layer is electrolyzed, then feeding the liquid into an upflow anaerobic sludge bed, and generating acetic acid, hydrogen and carbon dioxide by organic matters in a methanogenic reaction device under the action of acid-producing bacteria, and then converting the acetic acid, the hydrogen and the carbon dioxide into methane by the methanogenic bacteria.
2. The method of claim 1, wherein effluent from the upflow anaerobic sludge blanket is used to condition dilute wood vinegar.
3. The method for recycling pyroligneous acid as claimed in claim 1, wherein the formulation of the acetic acid solution in the step a of acclimatizing the anaerobic granular sludge in the step (5) is as follows: sodium acetate is used as a carbon source, the adding amount is 2000 mg COD/L, and NH is respectively used as a nitrogen source and a phosphorus source4Cl and KH2PO4Provided that the COD is N: P =200:5:1, and the other trace element formulas are shown in the table below; the other nutrient elements for domesticating the granular sludge are composed of mg/L, and the adding proportion is 1 mL/g COD microelement;
Figure DEST_PATH_IMAGE001
。
4. the method for recycling pyroligneous liquor according to claim 1, wherein the diameter of the woody columnar activated carbon is 1.5 mm, the packing density is 550 g/L or less, and the iodine value is 600 mg/g or more.
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CN109052578A (en) * 2018-08-22 2018-12-21 江南大学 A kind of preparation method of modified electrode and its method for continuous flow bioelectricity Fenton system processing waste water
CN110295201A (en) * 2019-06-26 2019-10-01 山东省科学院能源研究所 The method that ligno-cellulose hydrolysate prepares biogas
CN110350226A (en) * 2019-08-06 2019-10-18 农业农村部规划设计研究院 A kind of microorganism electrolysis cell and its method for handling wood vinegar
CN110451611A (en) * 2019-08-18 2019-11-15 深圳市世清环保科技有限公司 Composite three-dimensional electrolysis unit

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EP1005881A1 (en) * 1998-11-30 2000-06-07 Canon Kabushiki Kaisha Method and apparatus for decomposing halogenated aliphatic hydrocarbon compounds or aromatic compounds
CN101955280A (en) * 2010-08-13 2011-01-26 南京赛佳环保实业有限公司 Technology for processing high-concentration organic wastewater in composite electrochemical method
KR20130064173A (en) * 2011-12-08 2013-06-18 정이성 System for treating organic wastewater having high nitrogen content
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