EMIT Technologies believes that education of its’ customers on emissions and compliance solutions is one of its’ primary goals in providing a quality customer experience. Because of this, EMIT has invested in the staff, equipment, and the development of training programs that will provide organizations a better understanding of the emissions hurdles they face and how to address them.
In order to reduce emissions, modern engines carefully control the amount of fuel they burn. They try to keep the air-to-fuel ratio very close to the “stoichiometric point”, which is the calculated ideal ratio of air to fuel. Theoretically, at this ratio, all of the fuel will be burned using all of the oxygen in the air. The stoichiometric ratio for Natural Gas is approximately 17.2:1, meaning that for each pound of Fuel (Natural Gas) 17.2 pounds of air will be burned. The fuel mixture actually varies from the ideal ratio quite a bit during load changes. Sometimes the mixture can be lean (an air-to-fuel ratio higher than 17.2), and other times the mixture can be rich (an air-to-fuel ratio lower than 17.2)
The emissions from the combustion of natural gas (CH4) consists of at least 17 intermediate chemical species that occur during the conversion to CO2 & H2O. These intermediate species are ideally formed and consumed in the combustion process. However, under non-ideal conditions, not all of the intermediates are consumed fully and thus are emitted in the exhaust of the engine.
The major intermediates that are emitted are: CO, NO, NO2 (collectively considered NOx), and VOC’s (including formaldehyde [HCHO]).
There are a number of chemical elements that are found in the exhaust from a natural gas fired engine. The main emissions are:
These primary emissions are mostly benign (although carbon dioxide emissions are believed to contribute to global warming). However, because the combustion process is never perfect, some smaller amounts of more harmful emissions are also produced in engines:
These are the three main regulated emissions, and also the ones that catalytic converters are designed to reduce.
Emissions are typically measured using the following:
There are estimated to be well over 20,000 natural gas engines over 100 hp operating in the United States. Below is a calculation of the emissions from just one of these engines that is uncontrolled over just one year.
100 HP Uncontrolled Engine Produces:
CO = 16.5 tons per year
NOx = 9.7 tons per year
HC = 7 tons per year
Total 33.2 tons per year
A typical dump truck has a capacity of approximately 25 tons. This single uncontrolled 100 hp unit can produce the equivalent of 1.3 dump truck loads of emissions per year.
EMIT Technologies in specifically focused on assisting companies in addressing their emissions from natural gas engines. EMIT’s emissions mitigation solutions include a full line of Air Fuel Ratio Controllers and Catalyst that will take the emissions from an engine and significantly reduce their impact on the environment.
100 HP Controlled Engine to 0.5 g/bhp-hr:
CO = .489 tons per year
NOx = .489 tons per year
HC = .25 tons per year
Total 1.228 tons per year
Exhaust Leaks – NSCR (Three Way) Catalytic converters require a constant oxygen content of 0.5% or less at the inlet to maintain efficient reduction across the catalyst. Excess oxygen content will prevent NOx from being reduced efficiently.
Emissions are regulated at a number of levels.
EMIT has provided links under Emissions Regulations to the federal regulations and to the agencies involved in establishing and monitoring compliance at a state level.