Master of Science / Department of Mechanical and Nuclear Engineering / Kirby S. Chapman / In the natural gas production industry, recent legislation has mandated new emission
regulations for low horsepower reciprocating internal combustion engines. One method to
achieve compliance of the new regulations is the use of non-selective catalytic reduction. Nonselective
catalytic reduction utilizes a three-way catalyst and an air-to-fuel ratio controller to
oxidize carbon monoxide and unburned fuel while reducing oxides of nitrogen. Testing of a
non-selective catalytic reduction system was preformed on a typical exploration and production
engine, a Compressco GasJack. To fully test the unit, exhaust gas samples were taken with an
ECOM gas analyzer both before and after the catalyst over typical engine speeds and powers.
By sampling the exhaust gas concentration before and after the catalyst, the catalyst efficiency or
percent reduction in exhaust gas specific concentrations were calculated. Additionally by testing
throughout the engine's typical operation range, conditions under which the non-selective
catalyst reduction system fails were determined. After testing, it was found that the three-way
catalyst was effective at reducing oxides of nitrogen by 98% at all speeds and power conditions.
Carbon monoxide was reduced by 90% under all conditions except for maximum speed and
power. At maximum speed and power, the conversion efficiency for carbon monoxide was
recorded as low as 32%. One reason for the low conversion efficiency at maximum speed and
power was that the oxygen concentration entering the catalyst was not sufficient to oxidize the
carbon monoxide to carbon dioxide. These results indicate the three-way catalyst was effective
at reducing emissions when the controller correctly maintained the pre-catalyst oxygen
concentration. However, the controller was unable to maintain engine operation at the ideal airto-
fuel ratio at all test conditions. The controller failed to keep the pre-catalyst oxygen
concentration in the correct range because the oxygen sensor was not accurate and consistent in
its output. Future work on the development of a more robust oxygen sensor is recommended.
| Identifer | oai:union.ndltd.org:KSU/oai:krex.k-state.edu:2097/742 |
| Date | January 1900 |
| Creators | Wolfram, Kyle Martin |
| Publisher | Kansas State University |
| Source Sets | K-State Research Exchange |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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