CN102021055B - Anaerobic biological desulfurization method and device for methane - Google Patents

Abstract

The invention relates to a biogas desulfurization purification method and device. The content of the invention includes: introducing waste water or treated effluent containing oxides such as NO ₃ ^- , NO ₂ ^- , Fe3 ⁺ into the desulfurization tower from the spray liquid inlet (3), and evenly spraying on the elastic filler ( 7) on. The biogas enters the desulfurization tower through the biogas inlet (1) at the bottom of the desulfurization tower, is evenly distributed by the porous gas distribution plate (5), and alternately passes through the plastic air balls (6) attached with microorganisms and the elastic packing (7). Plastic air balloons (6) and elastic fillers (7) are alternately arranged. Desulfurization microorganisms attach to plastic air balloons (6) and elastic fillers (7) or are blocked by fillers in the reaction solution, and convert hydrogen sulfide into elemental sulfur or sulfuric acid with NO ₃ ^- , NO ₂ ^- , Fe3 ⁺ as electron acceptors Salt, to achieve the purpose of biogas desulfurization. After desulfurization, the biogas is discharged from the biogas outlet (2) at the top of the tower. The desulfurized spray liquid enters the bottom of the desulfurization tower and is discharged through the spray liquid outlet (4). The height of the vertical pipe connecting the spray liquid outlet (4) and the bottom of the tower should be about 2 times of the biogas pressure (water column).

Description

Biogas anaerobic biological desulfurization method and device

technical field

The invention relates to a gas separation and purification technology, in particular to a biogas anaerobic biological desulfurization method and device, which are suitable for livestock and poultry breeding waste, high-concentration industrial organic wastewater, residual sludge from urban sewage plants, crop straw and organic waste, etc. The desulfurization and purification treatment of biogas produced by anaerobic digestion biogas project is also suitable for the desulfurization of landfill gas or natural gas.

Background technique

Raw materials for biogas fermentation, such as livestock and poultry waste, high-concentration industrial organic wastewater, residual sludge from urban sewage plants, crop straw, and organic waste, are all biomass materials, which contain a considerable amount of organic or inorganic sulfur. During the process, it is converted into hydrogen sulfide, which is discharged with the biogas. Therefore, the biogas contains a certain amount of hydrogen sulfide. Hydrogen sulfide not only has a strong corrosive effect on combustion power equipment and metal pipes, but also causes deterioration of lubricating oil and accelerates engine wear. After the biogas is burned, hydrogen sulfide will be converted into sulfur oxides (SO _x ) and released into the air, causing air pollution. Hydrogen sulfide also has extremely strong acute toxicity. When the content of hydrogen sulfide reaches 0.6mg/L, it can cause death within 0.5-1 hour, and when the content is 1.2-2.8mg/L, it can cause death immediately. Therefore, in order to achieve the goals of safe utilization and environmental protection, artificial desulfurization of biogas must be carried out before use.

At present, there are mainly physical and chemical methods (including dry desulfurization and wet desulfurization) and biological methods for the removal of hydrogen sulfide from biogas. In physical and chemical methods, dry desulfurization is to use powder or granular desulfurizers (such as: iron-based, zinc-based, copper-based, calcium-based compounds, composite metal oxides and alkaline solids, molecular sieves, activated carbon, etc.) to remove hydrogen sulfide. The wet desulfurization method mainly uses liquid adsorbents (such as: arsenic-based compounds, iron chelates, ferric chloride, naphthoquinone, anthraquinone disulfonate, dinuclear phthalocyanine cobalt sulfonic acid, alkaline solution, etc.) to remove hydrogen sulfide. The desulfurization process of the physical and chemical method is basically to adsorb hydrogen sulfide on an adsorbent or a desulfurizer or react with hydrogen sulfide to form sulfide, and then use oxygen as an electron acceptor to oxidize hydrogen sulfide (sulfide) into elemental sulfur, so that the adsorbent or desulfurization agent regeneration. Due to the shortcomings of physical and chemical desulfurization methods, such as high energy consumption, high treatment costs, and difficult sludge disposal, biological desulfurization has received great attention in recent years, and photosynthetic bacteria and colorless sulfur bacteria desulfurization have been studied more.

Photosynthetic bacteria desulfurization is under anaerobic light conditions, photosynthetic bacteria use H ₂ S as hydrogen donor to reduce CO ₂ to synthesize bacterial cells, and H ₂ S is oxidized to elemental sulfur S ⁰ or further oxidized to sulfuric acid. Photosynthetic bacteria need a lot of radiant energy in the process of sulfur conversion. At the same time, after generating sulfur particles, the wastewater will become turbid and the light transmittance will be greatly reduced, thereby affecting the desulfurization efficiency. Therefore, photosynthetic bacteria desulfurization is greatly restricted.

Colorless sulfur bacteria can oxidize hydrogen sulfide to generate elemental or sulfuric acid, and obtain energy from the oxidation process, so as to achieve the purpose of desulfurization. Colorless sulfur bacteria can release the metabolite sulfur particles outside the cell during the metabolic process, and can achieve the purpose of desulfurization in the state of aerobic and oxygen concentration is the rate-limiting factor of biochemical reaction or the sulfide load is high. Compared with photosynthetic bacterial desulfurization, colorless sulfur bacterial desulfurization has more advantages, has been studied more deeply, and has been applied in engineering. Colorless sulfur bacterial desulfurization is essentially the same as physical and chemical desulfurization. It needs to provide oxygen as an electron acceptor, so it needs to consume energy to supply oxygen (air), but the supply of oxygen (air) is not easy to control, and oxygen remains in the biogas Easy to cause explosion hazard.

Contents of the invention

The present invention is a biogas anaerobic biological desulfurization method and device, using waste water containing oxides such as NO ₃ ^- , NO ₂ ^- , Fe ³⁺ , or waste water containing oxides such as NO ₃ ^- , NO ₂ ^- , Fe ³⁺ The effluent from the aerobic biological treatment project, oxidation pond, and constructed wetland is used as the desulfurization spray liquid for biological desulfurization. With NO ₃ ^- , NO ₂ ^- , Fe ³⁺ as electron acceptors and H ₂ S in biogas as electron donor, the biochemical reaction is carried out under the action of microorganisms to achieve the purpose of removing hydrogen sulfide. The main technical problems to be solved include: overcoming the problems of high operating costs of chemical desulfurization and labor-intensive replacement of desulfurizing agents, and solving the problems of difficult control of oxygen supply in aerobic biological desulfurization and danger caused by excessive oxygen.

Novelty of the present invention and beneficial effect are manifested in the following aspects:

(1) Biological desulfurization does not need to supply oxygen (air), avoiding the danger caused by excessive supply of oxygen;

(2) Avoiding the reduction of the calorific value of the biogas caused by the increase of the air content in the biogas;

(3) Reduced the energy consumption of blast;

(4) Good controllability, stable operation, good desulfurization effect, hydrogen sulfide removal efficiency can reach more than 95%;

(5) The operating cost is low, saving more than 80% compared with physical and chemical desulfurization, and saving more than 30% compared with aerobic biological desulfurization.

Description of drawings

Fig. 1 is a structural representation of the design of the present invention, wherein:

1-biogas inlet, 2-biogas outlet, 3-spray liquid inlet, 4-spray liquid outlet, 5-porous gas distribution plate, 6-spherical packing, 7-elastic packing, 8-spray nozzle.

Detailed ways

The present invention is further described in conjunction with drawings and embodiments.

Example 1. Referring to Fig. 1, the biogas anaerobic biological desulfurization device of the present invention is a vertical packed tower. The biogas inlet 1 and the biogas outlet 2 are respectively arranged at the top and the bottom of the tower. Plastic air balls 6 with a high specific surface area of φ25-50mm and elastic packings 7 are placed in the tower. The two types of packings are placed alternately. . A spray nozzle 8 is arranged above the top layer of packing, and is connected with the spray liquid inlet 3 . The spray liquid outlet 4 is located in the middle and upper part of the outer side of the tower and communicates with the bottom of the tower to ensure that a desulfurization liquid section with a height of 30-50 cm is formed in the tower. The height of the vertical pipe connecting the bottom of the tower and the spray liquid outlet 4 is about 2 times of the biogas pressure (water column).

Implementation steps of the present invention are as follows:

(1) Wastewater containing oxides such as NO ₃ ^- , NO ₂ ^- , Fe ³⁺ , or aerobic biological treatment projects, oxidation ponds, constructed wetlands containing oxides such as NO ₃ ^- , NO ₂ ^- , Fe ³⁺ The effluent is introduced into the desulfurization tower from the spray liquid inlet 3, and evenly sprayed on the elastic packing 7 through the spray nozzle 8.

(2) The biogas enters the desulfurization tower through the biogas inlet 1 at the bottom of the desulfurization tower, and after being evenly distributed through the porous gas distribution plate 5, alternately passes through the plastic air balls 6 attached with microorganisms and the elastic packing 7, and then passes through the biogas outlet 2 at the top of the tower discharge.

(3) The plastic air balloons 6 and the elastic fillers 7 are arranged alternately, which is beneficial to the uniform distribution of biogas and desulfurization liquid, avoids short flow, and saves the cost.

(4) Cultivate and domesticate desulfurization microorganisms in the desulfurization tower 9 with NO ₃ ^- , NO ₂ ^- , Fe ³⁺ as electron acceptors and H ₂ S in biogas as electron donors, and the desulfurization microorganisms attach to the plastic air balloon 6 and The elastic filler 7 is blocked in the reaction liquid by the filler, and the hydrogen sulfide is converted into elemental sulfur or sulfate, so as to achieve the purpose of biogas desulfurization.

(5) The desulfurized spray liquid enters the bottom of the desulfurization tower and is discharged through the spray liquid outlet 4. The spray liquid outlet 4 is located in the middle and upper part of the outer side of the tower and communicates with the bottom of the tower to ensure that a desulfurization liquid section with a height of 30-50 cm is formed in the tower. . The height of the vertical pipe connecting the bottom of the tower and the spray liquid outlet 4 should be about 2 times of the biogas pressure (water column), so as to ensure that the biogas will not escape from the spray liquid outlet 4.

(6) According to the concentration of NO ₃ ^- , NO ₂ ^- , Fe ³⁺ in the spray liquid and the content of hydrogen sulfide in the biogas, adjust the gas-liquid ratio of the biogas desulfurization process by adjusting the flow rate or spray time of the spray liquid to ensure the desulfurization effect.

Claims (5)

1. a biogas desulfurization refining plant, it is the thionizer of a band biogas import (1) and methane outlet (2), in tower, alternately place the plastics air balls (6) and elastic filler (7) of φ 25～50mm, the filler top of the Ta Nei the superiors arranges spray nozzle (8), and be connected with spray liquid import (3), spray liquid outlet (4) is positioned at outside tower middle and upper part and communicates with tower bottom, it is characterized in that: in thionizer, cultivate domestication with NO ₃ ^-, NO ₂ ^-, Fe ³⁺for electron acceptor(EA), with the H in biogas ₂s is electron donor desulfurization microorganism, desulfurization microorganic adhesion goes up or is barred from reaction solution by filler in plastics air balls (6) and elastic filler (7), hydrogen sulfide in methane is changed into elemental sulfur or vitriol, reach the object of biogas desulfurization.

2. biogas desulfurization refining plant according to claim 1, is characterized in that: contain oxide compound NO ₃ ^-, NO ₂ ^-, Fe ³⁺waste water or process water outlet from spray liquid import (3) introduce thionizer, be evenly sprayed in elastic filler (7) by spray nozzle (8).

3. biogas desulfurization refining plant according to claim 1, it is characterized in that: biogas enters thionizer by the biogas import (1) of thionizer bottom, after porous air distribution plate (5) is uniformly distributed, alternately, through the plastics air balls (6) and elastic filler (7) that are attached with microorganism, after desulfurization, biogas is discharged from the methane outlet (2) of top of tower.

4. according to biogas desulfurization refining plant described in claim 1 or 3, it is characterized in that: plastics air balls (6) and alternately layout of elastic filler (7), plastics air balls (6) and elastic filler (7) are for adhering to, stop desulfurization microorganism and water distribution uniformity gas distribution.

5. biogas desulfurization refining plant according to claim 1, it is characterized in that: the spray liquid after desulfurization enters thionizer bottom, export (4) by spray liquid and discharge, connect spray liquid outlet (4) and should be with the vertical tube height of tower bottom biogas pressure represents height 2 times of left and right with water column form.

Images