Is Waste Heat Recovery Required For Biogas Power Generation Units?

Is Waste Heat Recovery Required for Biogas Power Generation Units?

Biogas generator sets exhibit significant energy conversion losses, with their electrical output accounting for only 30%-40% of the total fuel energy. The remaining 60%-70% of energy is wasted as residual heat, primarily originating from two sources.

High-temperature flue gas residual heat: During operation, generators discharge flue gas at temperatures as high as 400-600°C, carrying substantial thermal energy.

Cylinder liner cooling water waste heat: Circulating cooling water at approximately 80-90°C is generated to cool the engine cylinder block, also containing recoverable thermal energy.

Recovering this waste heat can elevate overall energy utilization from 30%-40% to over 80%, significantly reducing energy waste.

The recovered waste heat can be flexibly utilized according to actual needs, with common applications falling into three categories:

Heating / Hot Water Supply: Utilizing waste heat for winter heating in farms, factories, or surrounding buildings, or providing hot water for domestic and industrial use, directly replacing traditional coal- or gas-fired boilers.

Aiding Biogas Production: In low-temperature environments, biogas digesters require maintaining an optimal temperature of approximately 35°C. Recovered waste heat can directly heat these digesters, enhancing biogas yield and stability.

Power Generation / Cooling: Steam generated by waste heat boilers drives turbines for secondary power generation. Alternatively, absorption chillers convert waste heat into cooling energy for workshop temperature control or refrigeration needs.