Pre and Post-Combustion NOx Control For Biogas Engine With Microwave Energy
Reducing NOx Emissions with Microwave Energy Technology
CHA Corporation
Recipient
Sacramento, CA
Recipient Location
8th
Senate District
6th
Assembly District
$646,603
Amount Spent
Completed
Project Status
$646,604
Award Amount
$122,554
Co-funded Amount
PIR-13-006
Agreement Number
-
Project Term
Sacramento, CA
Site Location(s)
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Project Result
Conclusions include:
Sulfur removal system effectively destroyed hydrogen sulfide, and can destroy siloxanes.
HALO system effectively reduced NOx, although not economical to control NOx with HALO alone since that requires a large amount of hydrogen to meet emission standards.
Activated carbon effectively reduces NOx emissions and removes ammonia, SOx, and volatile organic compounds.
Microwave regeneration of activated carbon brings the post-combustion NOx control system costs below conventional emission controls.
The Issue
The hydrogen sulfide and siloxanes in biogas poison catalysts used in the post-combustion nitrogen oxide (NOx) control methods and cause engine damage. Without additional emission controls, the exhaust from engines running on biogas exceeds the amended Rule 1110.2 emission standards. Because of catalyst poisoning, the post-combustion NOx control methods such as selective catalytic reduction (SCR) require an expensive biogas treatment to remove impurities. As a result, there are no engine manufacturers or post-combustion emission control providers that provide guarantees for emission controls of biogas engines that meet the Rule 1110.2 and CARB 2007 NOx emission standards.
Project Innovation
This project developed and demonstrated an integrated microwave system that addresses the current inability of biogas engines to meet the amended Rule 1110.2 and CARB's 2007 NOx emission standards. It provides a new emission-prevention technology to significantly reduce NOx and sulfur oxides (SOx) emissions from biogas engines. The integrated pre- and post-combustion NOx emission control process consists of two systems: a hydrogen production system for pre-combustion NOx control and a removal system on the engine exhaust for NOx and other pollutants.
Project Benefits
The integrated microwave system provides an innovative emission control strategy that overcomes the barriers to meet the amended Rule 1110.2 and CARB 2007 NOx emission standards. The pre-combustion NOx control reduces the NOx emissions substantially. The post-combustion NOx control system reduces NOx emissions below 5 parts per million.

Affordability
The NOx removal cost with the conventional technology (selective catalytic reduction) is $24,500 per ton of NOx removed. The NOx removal cost for the integrated post-combustion NOx control with microwave reactivation is $9,200 per ton of NOx removed or 1.8 cents per kWh power produced.

Economic Development
The project helps produce renewable fuel that is less costly to the environment. The system developed by the project could also produce hydrogen from biogas which would create more economic opportunities by allowing use of fuel cells for power generation in place of reciprocating engines.

Environmental Sustainability
The project reduces NOx emissions significantly using pre-and post-combustion NOx control with microwave energy to meet Rule 1110.2 and CARB 2007 NOx emission standards. Furthermore, the project demonstrates that the microwave devices can remove hydrogen sulfide from biogas and produce hydrogen.
Key Project Members

Chang Cha
Subrecipients

Sacramento Municipal Utility District

Clean World Partners, LLC

Match Partners

Sacramento Municipal Utility District

CHA Corporation
