Biogas Purification System

Biogas purification technology, processes and equipment are important links in the process of biogas utilization, aiming to improve the purity and availability of biogas to meet the needs of different fields.

The biogas purification method includes the processes of pressurization, filtration, biological desulfurization, deoxygenation, absorption, dehydration, compression and canning, and its implementation equipment includes a fan for conveying biogas, a first filter, a biological desulfurization tank, a deoxygenation device, a first compressor for increasing the air pressure in the flow channel, a buffer tank, a packing tower for absorbing carbon dioxide and hydrogen sulfide, a cold dryer, a fixed bed dehydration device, a second compressor for compressing the purified biogas, and a purified gas storage tank, which are connected in sequence.

Biogas purification technology and process mainly include three categories: chemical absorption, physical purification and biological removal.

Chemical absorption principle: chemical absorbents are used to react chemically with impurities in biogas to remove impurities.

Physical purification principle: different components are separated by using the different adsorption forces of adsorbents on different gases under different pressure conditions.

Biological purification principle: impurities in biogas are removed by the metabolism of microorganisms.

Common methods: biological desulfurization, biological decarbonization, etc. By cultivating specific microbial populations, they react with impurities in biogas to remove impurities.

The general biological desulfurization process in the form of biological filter bed and biological trickling filter is prone to blockage of elemental sulfur. The biological desulfurization process provided by our company can effectively avoid the above situation and is a very stable and reliable process.

The biological desulfurization process can be divided into three units:

① desulfurization washing unit;

② washing liquid biological regeneration (reuse) unit;

③ elemental sulfur separation unit.

Desulfurization washing: Alkaline biological washing liquid is sprayed from the top of the washing tower and countercurrently contacts with the sulfur-containing compound (mainly H₂S) gas source entering from the bottom of the washing tower. Since the regenerated biological washing liquid contains polythionate substances with desulfurization catalytic effect, H₂S can be absorbed efficiently and removed very cleanly.

Biological regeneration reactor: The rich liquid containing sulfide flows into the biological regeneration reactor from the bottom of the washing tower. Through the biological treatment of desulfurization microorganisms, the biological washing liquid is regenerated and alkalinity is restored. Then it is pumped into the first unit washing part for repeated use.

Elemental sulfur separation: Elemental sulfur is separated from the biological desulfurization system in the form of particle precipitation from the elemental sulfur separator, and the clear liquid after separation is returned to the biological regeneration reactor. The biological desulfurization process, ideally, does not produce pollution.

Biogas purification equipment mainly includes desulfurization equipment, dehydration equipment, fine filtration equipment and control system.

(1) Scrubber

Due to the characteristics of alkaline scrubbing liquid, the material of the scrubber is FRP (glass fiber reinforced plastic). Number of scrubbers: 1; size: ø1400mm*17500mm(H);

Related facilities in the tower include: internal filling material, nozzle, scrubber pipe, filling material support, water distributor, defoaming spray device, defoamer, etc.

Auxiliary facilities include: foundation and H steel working platform.

(2) Regeneration reactor

After the washing liquid absorbs hydrogen sulfide in the washing tower, the absorbed hydrogen sulfide is converted into elemental sulfur by controlling the oxidation process in the biological regeneration reactor. The indicators to be controlled in the reactor during the treatment process are: pH, temperature, redox potential, and conductivity.

Therefore, in the process from the washing tower to the biological regeneration reactor, it is necessary to supplement: water and alkali lost in the process of gas carrying out and discharging elemental sulfur, nutrients required by organisms, and a certain amount of oxygen (isolated from the gas source) to maintain the redox potential.

The design size of the biological regeneration reactor is: ø3800*6000mm (H) 1 unit;

Material: FRP, auxiliary facilities include: aerator, degassing tank, defoaming spray device, etc.

(3) Plate heat exchanger

Due to climate change and the release of biological metabolic energy, the temperature inside the bioregeneration reactor may exceed the temperature that the bacteria can withstand. A plate heat exchanger is required to cool the washing liquid.

(4) Sedimentator

The function of the elemental sulfur precipitator is to separate elemental sulfur and maintain the sulfur balance of the washing liquid.

The elemental sulfur precipitator is made of FRP; it is equipped with a jacketed sedimentation area, guide plate, internal pipe fittings, etc.

(5) Washing pump

The circulating spray pump for biological washing liquid: material: pump housing/impeller s316;

(6) Aeration fan (Roots blower)

The conveying equipment selects Roots blower for biogas pressurization, which is used to fill a small amount of oxygen into the bioregeneration reactor. It is automatically controlled by PLC. There are 2 fans, one for use and one for backup.

(7) Others

Required configuration: 2 nutrient solution metering pumps; 2 supplementary alkali metering pumps; 2 sulfur sludge pumps (1 for use and 1 for backup) (pneumatic diaphragm pumps);

1 measuring pump for use and 1 for backup, 2 in total; all automatically controlled by PLC.

Function of dehydration equipment: remove water vapor from biogas and improve the calorific value and stability of biogas.

Common types: condenser, drying tower, etc.

Function of fine filtration equipment: remove tiny particles and impurities from biogas and further improve the purity of biogas.

Common types: fine filter, filter, etc.

Features: fine filtration equipment usually uses high-efficiency filter materials, which can effectively remove impurities and particles in biogas.

Function of control system: monitor and adjust the operating status of the entire biogas purification system to ensure safe and stable operation of the system.

Composition: including sensors, controllers, actuators, etc.

The entire biogas treatment system is controlled by PLC. The PLC control system uses Siemens s7-1500 series. The operation station controls the biogas treatment process in real time and collects field data through SCADA. The main parameters such as temperature, flow, pressure, liquid level, conductivity, reduction potential, etc., also monitor, display and control the status of the measured equipment (such as regeneration reactor, motor, etc.).

Each device can be remotely controlled, and the process parameters can be set through corresponding operations. The above-mentioned measuring instruments and running equipment can also be controlled on site. At the same time, the process operation data collection and recording are realized, which is convenient for operators to analyze the system operation status in real time.

Mixing equipment: used for mixing and homogenizing raw materials, mainly divided into two categories, paddle mixer and submersible mixer.

Screen machine: used to remove large debris in the raw materials to prevent clogging of subsequent equipment.

Feed pump: used to lift the raw materials to the subsequent construction facilities to ensure the smooth transportation of raw materials.

Biogas steam boiler: used for heating and heat preservation treatment of biogas projects to ensure long-term normal gas production of biogas projects.

Solid-liquid separator: used to dehydrate and concentrate biogas residues to reduce the volume and weight of biogas residues.

 

Biogas purification technology is mainly used in agricultural waste treatment, industrial wastewater and urban sewage treatment, livestock and poultry farms, agricultural and sideline product processing, biogas power stations, landfills and other scenarios. It not only helps to achieve sustainable use of energy and reduce dependence on fossil fuels, but also protects the environment and promotes the resource utilization of waste.

 

Hot Tags: biogas purification system, China biogas purification system manufacturers, suppliers, factory, 350KW Natural Gas Generator Set, Natural Gas Purification System, emission control catalysts, exhaust aftertreatment system, biogas generator set, 1000 Kw Natural Gas Generator