Biogas cold-drying booster system is usually installed after a digester or a double-membrane gas cabinet, so that the biogas is pressurized to a certain pressure (such as 10-20Kpa) and dehumidified to a certain humidity (such as 80%), and drives the biogas boiler, biogas torch or biogas generator to operate efficiently.

The biogas cold-drying booster system adopts a skid-mounted design, integrating functions such as drying and dehydration, filtration and decompression, frequency conversion boosting, safety protection, etc., making it convenient for installation and debugging.

Main Functions

Constant pressure automatic control function - increase the biogas pressure to a stable value

Dust removal function one: Reduce the content of dust and other organic impurities

Dehumidification function 1: Reduce the relative humidity of the gas to 70%

Stainless steel components with anti-corrosion treatment ensure the service life of the equipment

The main equipment is designed in a modular way, which is convenient for transportation, installation, maintenance and scale expansion

Condensation and Dehydration Process

The relative humidity of the biogas after desulfurization is saturated and cannot meet the requirements of 80% of the relative humidity of the intake air of the back-end generator set. Therefore, this project has set up a condensation and dehydration process.

This process mainly uses a soda and water heat exchanger combined with an air-cooled chiller to realize the full heat exchange of high-temperature biogas with the low-temperature refrigerant generated by the chiller after entering the soda and water heat exchanger. While the gas temperature decreases, the gaseous water condenses and precipitates, and the cooling biogas enters the downstream process; the heated refrigerant liquid returns to the chiller for refrigeration and recycling.

The soda heat exchanger uses a shell and tube structure, with biogas passing through the shell and refrigerant liquid passing through the pipe, and the gas-side resistance loss shall not exceed 2KPa. After the high-temperature biogas passes through the heat exchanger, the dew point temperature drops to about 15°C. The large amount of water vapor carried in the gas condenses and precipitates as the temperature decreases. A liquid water separator is integrated inside the heat exchanger, which can effectively separate the condensed liquid water and discharge it from the equipment.

The chiller uses an air-cooled intelligent all-in-one machine, which can automatically monitor the temperature of the supply and return water and the pressure on the water side.

This system uses a Roots fan as a pressurized and pressure-regulating device, which is mainly used to overcome the system resistance loss, provide sufficient power for the circulation of biogas in the system, and meet the inlet pressure requirements of the backend system.

On the basis of meeting the pressure-regulated operation of the rear-end gas system, this project comprehensively considers the flow resistance losses of various processing equipment, pipelines, valves, instruments, pipe fittings, etc. in the system. The boost capacity of the Roots fan is designed to be 30KPa, which is suitable for 11KW explosion-proof motors and inverters.

While the Roots fan presses the gas along the gas, the gas temperature increases accordingly, thereby effectively reducing the relative humidity of the gas and meeting the requirement of 80% of the system outlet relative humidity. As the main power conveying equipment inside the system, the Roots fan adopts two parallel sets, one is used and one is prepared to ensure that the system does not stop operating during maintenance and maintenance of a single device.

Gas Dehumidification and Gas Cooling in One Loop

The process gas is dehumidified according to the principle of condensation and drying. For this purpose, a water-cooled shell and tube heat exchanger is used. When the airflow cools, the moisture condenses and can then be removed from the process. If condensate water forms during cooling, it is collected in a condensate water collection container while the liquid level is monitored. The condensate pump discharges the condensate. After cooling, the gas can be selected through the defogging device. Up to 99% of the condensate droplets are captured by wire mesh bags (miles). All components in contact with the medium are made of high-quality stainless steel (316L or equivalent), which ensures a long service life of the system.