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In-Use Efficiency of Oxidation and Three-Way Catalysts Used in High-Horsepower Dual Fuel and Dedicated Natural Gas Engines
Journal Article
03-11-03-0026
ISSN: 1946-3936, e-ISSN: 1946-3944
Sector:
Topic:
Citation:
Johnson, D., Darzi, M., Clark, N., Nix, A. et al., "In-Use Efficiency of Oxidation and Three-Way Catalysts Used in High-Horsepower Dual Fuel and Dedicated Natural Gas Engines," SAE Int. J. Engines 11(3):383-398, 2018, https://doi.org/10.4271/03-11-03-0026.
Language:
English
Abstract:
Directional drilling rigs and hydraulic stimulation equipment typically use
diesel fueled compression ignition (CI) engines. The majority of these engines
are compliant with US Environmental Protection Agency (EPA) Tier 2 standards. To
reduce fuel costs, industry is investing in dual fuel (DF) and dedicated natural
gas (DNG) engines. DF engines use diesel oxidation catalysts (DOCs) to reduce CO
and NMHC emissions. DNG engines may be either lean-burn or rich-burn and the
latter uses three-way catalysts (TWC) to reduce CO, NMHC, and NOx
emissions. This research presents in-use catalyst efficiency data collected pre-
and post-catalyst for three DF engines and two DNG engines. One DF engine was
converted earlier and did not include a DOC. Data were collected from six Tier 2
engines, two CI drilling engines converted to operate as DF, two CI hydraulic
fracturing engines converted to operate as DF, and two SI DNG drilling engines.
DF engines with DOCs were able to reduce CO and NMHC during DF operation by
>90 and >50%, respectively. The DOCs did not reduce methane and
NOx emissions. One DNG catalyst did not effectively reduce
emissions. Properly functioning DNG engines and TWCs decreased engine out CO,
NMHC, and NOx emissions all by >90%. It is important to note that
DOCs could be added to Tier 2 diesel engines regardless of combustion mode to
reduce engine out NMHC and CO emissions. DNG engines offered the lowest
NOx emissions, which could be important in certain air districts.
Research should focus on improved oxidation of methane emissions from DF engines
to realize any benefit of reduced of GHG emissions.