Affected unit means an engine meeting the applicability criteria of this section.
Cap means the total amount of NOX emissions, in tons per day on a 30-day rolling average basis, that is collectively allowed from all of the affected units covered by a Facility-Wide Averaging Plan and is calculated as the sum each affected unit's NOX emissions at the emissions limit applicable to such unit under paragraph (c) of this section, converted to tons per day in accordance with paragraph (d)(3) of this section.
Emergency engine means any stationary reciprocating internal combustion engine (RICE) that meets all of the criteria in paragraphs (i) and (ii) of this definition. All emergency stationary RICE must comply with the requirements specified in paragraph (b)(1) of this section in order to be considered emergency engines. If the engine does not comply with the requirements specified in paragraph (b)(1), it is not considered an emergency engine under this section.
Facility means all of the pollutant-emitting activities which belong to the same industrial grouping, are located on one or more contiguous or adjacent properties, and are under the control of the same person (or persons under common control). Pollutant-emitting activities shall be considered as part of the same industrial grouping if they belong to the same "Major Group" (i.e., which have the same first two digit code as described in the Standard Industrial Classification Manual, 1987). For purposes of this section, a facility may not extend beyond the 20 states identified in § 52.40(b)(2) .
Four stroke means any type of engine which completes the power cycle in two crankshaft revolutions, with intake and compression strokes in the first revolution and power and exhaust strokes in the second revolution.
ISO conditions means 288 Kelvin (15 °C), 60 percent relative humidity, and 101.3 kilopascals pressure.
Lean burn means any two-stroke or four-stroke spark ignited reciprocating internal combustion engine that does not meet the definition of a rich burn engine.
Local Distribution Companies (LDCs) are companies that own or operate distribution pipelines, but not interstate pipelines or intrastate pipelines, that physically deliver natural gas to end users and that are within a single state that are regulated as separate operating companies by State public utility commissions or that operate as independent municipally-owned distribution systems. LDCs do not include pipelines (both interstate and intrastate) delivering natural gas directly to major industrial users and farm taps upstream of the local distribution company inlet.
Local Distribution Company (LDC) custody transfer station means a metering station where the LDC receives a natural gas supply from an upstream supplier, which may be an interstate transmission pipeline or a local natural gas producer, for delivery to customers through the LDC's intrastate transmission or distribution lines.
Nameplate rating means the manufacturer's maximum design capacity in horsepower (hp) at the installation site conditions. Starting from the completion of any physical change in the engine resulting in an increase in the maximum output (in hp) that the engine is capable of producing on a steady state basis and during continuous operation, such increased maximum output shall be as specified by the person conducting the physical change.
Natural gas means a fluid mixture of hydrocarbons (e.g., methane, ethane, or propane) or non-hydrocarbons, composed of at least 70 percent methane by volume or that has a gross calorific value between 35 and 41 megajoules (MJ) per dry standard cubic meter (950 and 1,100 Btu per dry standard cubic foot), that maintains a gaseous state under ISO conditions. Natural gas does not include the following gaseous fuels: Landfill gas, digester gas, refinery gas, sour gas, blast furnace gas, coal-derived gas, producer gas, coke oven gas, or any gaseous fuel produced in a process which might result in highly variable CO2 content or heating value.
Natural gas-fired means that greater than or equal to 90% of the engine's heat input, excluding recirculated or recuperated exhaust heat, is derived from the combustion of natural gas.
Natural gas processing plant means any processing site engaged in the extraction of natural gas liquids from field gas, fractionation of mixed natural gas liquids to natural gas products, or both. A Joule-Thompson valve, a dew point depression valve, or an isolated or standalone Joule-Thompson skid is not a natural gas processing plant.
Natural gas production facility means all equipment at a single stationary source directly associated with one or more natural gas wells upstream of the natural gas processing plant. This equipment includes, but is not limited to, equipment used for storage, separation, treating, dehydration, artificial lift, combustion, compression, pumping, metering, monitoring, and flowline.
Operating day means a 24-hour period beginning at 12:00 midnight during which any fuel is combusted at any time in the engine.
Pipeline transportation of natural gas means the movement of natural gas through an interconnected network of compressors and pipeline components, including the compressor and pipeline network used to transport the natural gas from processing plants over a distance (intrastate or interstate) to and from storage facilities, to large natural gas end-users, and prior to delivery to a "local distribution company custody transfer station" (as defined in this section) of an LDC that provides the natural gas to end-users. Pipeline transportation of natural gas does not include natural gas production facilities, natural gas processing plants, or the portion of a compressor and pipeline network that is upstream of a natural gas processing plant.
Reciprocating internal combustion engine (RICE) means a reciprocating engine in which power, produced by heat and/or pressure that is developed in the engine combustion chambers by the burning of a mixture of air and fuel, is subsequently converted to mechanical work.
Rich burn means any four-stroke spark ignited reciprocating internal combustion engine where the manufacturer's recommended operating air/fuel ratio divided by the stoichiometric air/fuel ratio at full load conditions is less than or equal to 1.1. Internal combustion engines originally manufactured as rich burn engines but modified with passive emissions control technology for nitrogen oxides (NOX) (such as pre-combustion chambers) will be considered lean burn engines. Existing affected unit where there are no manufacturer's recommendations regarding air/fuel ratio will be considered rich burn engines if the excess oxygen content of the exhaust at full load conditions is less than or equal to 2 percent.
Spark ignition means a reciprocating internal combustion engine utilizing a spark plug (or other sparking device) to ignite the air/fuel mixture and with operating characteristics significantly similar to the theoretical Otto combustion cycle.
Stoichiometric means the theoretical air-to-fuel ratio required for complete combustion.
Two stroke means a type of reciprocating internal combustion engine which completes the power cycle in a single crankshaft revolution by combining the intake and compression operations into one stroke (one-half revolution) and the power and exhaust operations into a second stroke. This system requires auxiliary exhaust scavenging of the combustion products and inherently runs lean (excess of air) of stoichiometry.
Equation 1 to Paragraph (d)(3)
Where:
Hi = the average daily operating hours based on the highest consecutive 30-day period during the ozone season of the two most recent years preceding the emissions averaging year (hours).
i = each affected unit included in the Cap.
N = number of affected units.
DC = the engine manufacturer's design maximum capacity in horsepower (hp) at the installation site conditions.
Rli = the emissions limit for each affected unit from paragraph (c) of this section (grams/hp-hr).
Equation 2 to Paragraph (f)(6)
Where:
Hai = the consecutive 30-day rolling average daily operating hours for the preceding 30 operating days during ozone season (hours).
i = each affected unit.
N = number of affected units.
DC = the engine manufacturer's maximum design capacity in horsepower (hp) at the installation site conditions.
Rai = the actual emissions rate for each affected unit based on the most recent performance test results, (grams/hp-hr).
40 C.F.R. §52.41