In landfills, biodegradable waste generates variable levels of landfill gas throughout its decomposition process. The usable landfill gas—i.e., the one suitable for powering combustion operations—generally ranges around 50% methane by volume. As such, landfills that produce low calorific volume (low-CV) gas—i.e., gas with less than 50% (typically 30% or lower) methane by volume—are less likely to run effectively and efficiently. Two of the factors that affect whether a landfill produces low-CV gas are the quality (i.e., the methane content) and the quantity (the flow/volume collected) of the extracted gas.
The following article addresses the latter point—i.e., landfills with low flow/volume landfill gas collection rates. While this condition significantly reduces the energy efficiency of the landfill, the proper landfill gas management plan can minimize the severity of the effect.
The Importance of Conserving Power When Gas Flow Is Low
As indicated above, low gas flow significantly affects a landfill’s overall efficiency and effectiveness. As such, handling the issue properly if and when it occurs is critical. In addition to identifying and resolving the cause of low flow (e.g., inadequate levels of overall waste or biodegradable compounds), it is important to conserve power until an appropriate solution is implemented.
One potential solution for conserving power in low gas flow situations is integrating variable frequency drives (VFDs) in the landfill’s motorized systems. These devices allow the systems to change speeds to accommodate more efficient and effective power consumption requirements. However, they are expensive, especially when used in medium-voltage and high-horsepower systems.
Power-Saving Solutions for Low Gas Flow Situations at GEC
At Glauber Equipment Corporation (GEC), we specialize in fluid and air flow equipment and systems. For the biogas and landfill markets, we provide gas separation and compression solutions, including blowers, compressors, and dehydration units, all of which serve a critical role in the waste decomposition and gas production processes.
The compression stages of the processes rely on compressors. For these operations, we supply between two to four units, all of which are engineered to shut off in low flow conditions to conserve energy. For example, if the flow drops to 75% the normal operating conditions, one of four compressors may shut off to balance flow output with power input. Another advantage of this design is that repair and maintenance can be performed without halting production completely.