Landfill gas, or LFG, comes from decomposing solid waste. Often considered a foul-smelling hazard and source of air pollution, it can also be captured, refined, and reused for energy production. Shell and tube heat exchangers are critical throughout the processing stages that convert LFG to fuels and other energy sources.
Keep reading to learn more about landfill gas, how it can be reused to benefit the environment, and the role shell and tube heat exchangers play in the process.
What Is Landfill Gas?
When trash is added to a landfill, it decomposes over time. Initially, decomposition is aerobic (i.e., in the presence of oxygen); however, after several months, the decomposition becomes anaerobic (i.e., without oxygen). This anaerobic decomposition results in LFG.
LFG is composed of many different gases, but primarily methane and carbon dioxide, approximately 45-60% and 40-60% respectively. It also contains small amounts of carbon monoxide, hydrogen, sulfides, ammonia, oxygen, nitrogen, and nonmethane organic compounds, including vinyl chloride, benzene, and trichloroethylene.
Is Landfill Gas a Renewable Energy Source?
As a byproduct of decomposition, LFG is naturally released into the surrounding environment, generating odors and air pollution. Instead of allowing the gas to escape, many landfills recapture or extract it for processing. This converts it into fuel that can be used directly for medium-BTU applications or used to power turbines to generate electricity. It can also be further processed for use as vehicle fuel or added to gas pipelines.
LFG also stands out among renewable resources like wind and solar because it is constantly being produced. While wind speeds vary and the sun sets each night, trash never stops decomposing and generating LFG.
According to the EPA, landfill gas offers many environmental benefits:
- It is a renewable and safe energy resource.
- It reduces reliance on using other polluting forms of energy.
- It reduces air pollution and other risks to health and the community.
The EPA also notes several economic advantages of LFG:
- LFG is a ubiquitous and consistent local resource and recycling it is cost-effective.
- Reusing LFG can generate economic advantages for the local community.
- LFG energy projects can create local jobs.
- Landfill energy sources have the potential to attract businesses to the area.
Landfill Gas Coolers, Heat Exchangers, from Enerquip
How Shell and Tube Heat Exchangers Assist in Recycling and Recovering LFG
LFG recovery and processing involves many steps. Shell and tube heat exchangers are an important part of the process.
LFG Collection and Processing
- Collection. Escaping LFG is collected through a network of pipes and wells.
- Processing. Moisture is removed from the LFG so that siloxane and sulfur can be removed to create fuel for electricity production or medium-BTU applications.
- Advanced processing. Removing carbon dioxide, nitrogen, oxygen, and VOCs creates fuel for vehicles or to be added to gas pipelines.
The Role of Shell and Tube Heat Exchangers
- Cooling and Condensation. Shell and tube heat exchangers help cool raw LFG, condensing the moisture to separate it. This prevents corrosion of equipment due to moisture.
- Heating for Siloxane Removal. Shell and tube heat exchangers heat LFG to separate siloxanes. This protects downstream equipment and improves gas quality.
- Heat Recovery. Shell and tube heat exchangers help recover heat from combusting purified LFG. The recovered heat can be reused in other processes to improve efficiency.
Energy Production
- Fuel for Engines or Turbines. Purified LFG can be used to power turbines or reciprocating engines to generate electricity. Heat exchangers assist in maintaining ideal operating temperatures.
Environmental Benefits
- Reduced Emissions. Heat exchangers assist in efficient cooling and purification of landfill gas, reducing harmful emissions.
- Energy Efficiency. Incorporating heat exchangers allows for the recovery and use of waste heat.
Challenges and Considerations
- Corrosion and Fouling. Heat exchangers require protection from corrosion and fouling from gas impurities.
- Maintenance. Regular maintenance is required for efficiency and optimal performance in extreme operating conditions.
Heat Exchangers From Enerquip for Landfill Gas Applications
As the world moves towards renewable energy sources, biofuels like LFG are an ideal solution for powering equipment that generates electricity and in other applications. Shell and tube heat exchangers are a critical part of the LFG capture and refining process.
Enerquip’s high-quality equipment helps you meet landfill gas renewable energy demands. Contact us or request a quote to get started.