China 10000 Nm3 D Biogas Upgrading Plant to Natural Gas

Project informations:
10000 Nm3/d Biogas upgrading Plant
Location: Yifeng, Jimo City, Shangdong Province, China;
Decarburization techonology: membrane separation in containerized canopy
CNG application: for nearby household
After two-stage desulphurization processes, then go through our GasDec system for carbon removal, biogas could be upgraded to make CNG, for vehicle or going into national pipeline network.
The gas quality after upgrading as below:
ItemQuality IndexCommentsHigh thermal
value MJ/m3>31.4In the specific geographical area for vehicle driving, under the highest operation pressure, the water dew point shouldn't be higher than -13 degree.C; When lowest ambient temperature lower than -8 degree.C, the water dew point should be 5 degree.C lower than the lowest temperature.CO2%≤3.0Total Sulfurmg/Nm3≤200H2Smg/Nm3≤15O2%≤0.5Comments: The above data is subject to clients' actual requirements.
The Flowchart of biogas upgrading system
Procedures of our biogas upgrading system

1, Biogas GenerationBiogas is generated in anaerobic reactor and stored in gas holder in low pressure. Boosted by biogas blower, biogas is delivered to wet desulphurization tower;

2, Wet DesulphurizationWet chemical desulphurization technology is mainly structured as a single tower. Chemicals adopted is Na2CO3 with addition of catalysts (oxygen carrier). Chemicals is dissolved in the water, contact rightabout with biogas in the tower. More than 95% hydrogen sulfide, a small amount of carbon dioxide and other acidic substances can be absorbed by the liquid.
The pregnant solution (the liquid) would be boosted by pump to a special groove, sprayed and oxidized by means of air suction for regeneration. Meanwhile elemental sulfur is precipitated out of the liquid, to be recycled for sale.

3, Dry DesulphurizationDry chemical desulphurization technology is for the purpose of fine desulphurization, mainly structured as double towers, can be used alternately or operated in parallel or in series. Chemicals adopted is usually ferric oxide. Hydrogen Sulfide is converted to solid sulfide.

4, Gas CleaningThe gas is boosted by biogas compressor, then after procedures of cooling, water and impurities removal, to be delivered to decarburization unit.

5, Biogas DecarburizationThe decarburization technology we adopt is chemical absorption. Chemical solution contacts with biogas rightabout in the absorption tower, to absorb carbon dioxide till its content lower than 3%.
The upgraded gas is discharged from top of absorption tower, to be cooled by cooler and cleaned by separator for the removal of condensate water and chemical solution. Then gas is delivered to compressor.
The pregnant solution (the liquid) returns to the regeneration tower. The precipitation of carbon dioxide is achieved through steam stripping. The precipitated carbon dioxide gets through cooler and separator, can be discharged into atmosphere directly. The barren solution from the bottom of regeneration tower is pumped through automatic flow monitoring pipeline into absorption tower for circulatory use.
This is our GasDec system.

1, NG CompressorThe gas after decarburization procedure we can call it natural gas now. Its pressure rises to 22MPa or other pressure levels by natural gas compressor.

2, NG CleaningThe compressed natural gas would be dried and cleaned further by automatic NG drier. The working principle of drier is pressure swing absorption, taking 4A molecular sieve as absorbent.

3, CNG MeteringCNG metering device is required when gas is for sale. Measuring method we usually adopt mass measurement. Eg. The mass flowmeter of our project in Henan Province of China is Emerson CNG050, accuracy could reach 0.5 magnitude. Gas is filled into CNG tank lorry through gas dispenser machine, to be delivered to standard CNG station (or Primary CNG station) as fuel for vehicle.
Main equipment list of our upgrading system
No.ItemCommentsBiogas Desulphurization System1Wet Desulphurization Tower 2Groove,Pregnant Solution 3Groove,Barren Solution 4 Groove,regeneration 5Separator 6Dry Desulphurization Tower 7Regeneration Pump 8Pump,Desulphurization 9Pump,Sulfur Foam 10Biogas Blower 11Electrical Monitoring 12Alarming System Biogas Decarburization System1Pump,barren Solution 2Decarburization TowerMethane Recovery: ≥99%,
Gas quality satisfies GB18047-2000 standard3On-line Analyzer 4On-site control box 5PLC System 6Operator Station 7On-line UPS 8Automatic flowmeter 9Motorized Valve 10Pressure Transmitter 11On-site Pressure Gauge 12On-site Temperature Gauge 13Liquid level Gauge 14Frequency Converter 15Filter 16Storage Tank 17Underground Groove 18Underwater Pump 19Biogas Compressor 20Power Distribution CabinetAssembling UnitCNG Compressing, drying and metering Unit1CNG Compressor 2Dryer 3Gas Dispenser Machine Circulatory Cooling Water Unit1Circulatory water system