Hydrous Ethanol Reforming for Reducing NOx Emissions from Diesel Engines

University of Minnesota/William Northrop

The University of Minnesota (UMN) has demonstrated a dual-fuel hydrous ethanol injection system for use on existing diesel engines that can replace up to 40% diesel fuel use by energy with ethanol. We have also demonstrated that 180 proof hydrous ethanol production can save 10% in plant natural gas usage and reduce net plant water use up to 6%.

The primary motivations for developing a viable hydrous ethanol dual-fuel system are to expand the market for ethanol to diesel-powered applications and to reduce pollutant emissions from diesel engines. One key market driver for dual fuel systems is to use them as an alternative to add-on catalytic aftertreatment systems for off-highway engines meeting the California Air Resources Board (CARB) Diesel Risk Reduction Plan verification levels for in-use engines. However, based on our evaluation of existing aftermarket dual-fuel systems including our own, injecting ethanol into the intake of a diesel engine does not reduce nitrogen oxide emissions (NOx) compared to diesel only operation. This is due to chemistry in the engine cylinder that enhances conversion of NO to NO2 from excess ethanol in fuel-lean areas.

The primary goal of this project is to develop an aftermarket hydrous ethanol reforming system that would meet CARB in-use standards for both particulate matter (PM) and NOx, an achievement that has not been achieved by any dual-fuel ethanol systems to date.