Gas heaters of pressure reduction stations in the gas company are one of the important sources of air pollutants, which emits large amounts of polluting gases daily through the chimney of these heaters, due to the existence of more than 2000 heaters in CGS stations, today at the level Gas companies have implemented many projects to optimize and reduce environmental pollutants. In the direction of optimization, a project was carried out regarding the modification of the structure of the heaters in Zanjan gas company, and this research project led to a reduction in consumption and as a result, a reduction in the emission of pollutants and greenhouse gases. The new heater installed in the pressure reduction station of shahr Khorram darre and comparing the results with the measured values of the traditional heaters in the station and their compliance with the existing standards has been done. Experimental studies show a decrease in the value by 32% and a decrease of 22.3%. The percentage of emission as well as a decrease of 28.9% in the amount of gas produced and a decrease in the amount of 16.7% and subsequently a decrease of 20.3%.

Introduction
Today, environmental pollution is one of the major problems of societies, especially industrial societies. Carbon dioxide compounds, carbon monoxide and nitrogen compounds are among the main pollutants of the environment. In addition to affecting the surrounding ecosystem, these pollutants also have a great impact on the physical and mental health of people. On the other hand, the importance of fossil fuel combustion for energy production in industry, vehicles and household use is not hidden from anyone, more than 90% of the energy consumed in the world and nearly 100% of the energy consumed in Iran is obtained from the combustion of fossil fuels. The ever-increasing increase in energy consumption, the limited and rapid reduction of fossil fuel resources, and the environmental problems of these fuels have caused the design of "clean" combustion devices with high efficiency to be the focus of many researchers and designers. Ninety percent of fossil fuel consumed in the country today In domestic, commercial and industrial sectors, natural gas is natural gas. Natural gas is mostly composed of methane and small amounts of heavier hydrocarbons such as ethane, propane, butane, pentane, etc. In some cases, natural gas contains small amounts of hydrogen, carbon dioxide, nitrogen, oxygen, sulfur compounds, and water. The heating value of natural gas depends on the percentage of hydrocarbons and inert gases in it. City gate pressure reduction stations (CGS) are located at the entrance of cities to reduce the high pressure of gas flowing from the refinery to consumption points. In these stations, the gas pressure is reduced to the desired value by pressure relief valves. By reducing the pressure of natural gas in the pressure reduction stations, its temperature decreases, which can lead to freezing and formation of hydrates and blockage of gas in the pressure relief valves. Therefore, to prevent the phenomenon of dehydratation, the temperature of the gas must be increased before reducing the pressure. The increase in temperature in the stations is done by reducing the pressure by heaters. There are different types of gas station heaters, the most common types of heaters used in the gas industry are linear heaters. Due to the high fuel consumption and low efficiency Heaters, as well as the ever-increasing price of energy and non-compliance with energy consumption standards and environmental standards, today the optimization of these heaters has been the focus of Iran's National Gas Company, and measures have been taken to optimize and reduce consumption by gas companies. Province has taken place. These optimizations in order to reduce consumption and reduce greenhouse gases are one of the most important environmental issues that humanity is facing today. Global warming and climate change. The main reason for this issue is the emission of greenhouse gases that result from the combustion of fossil fuels. The formation of various environmental conventions also shows the importance of the issue. The Kyoto Protocol is one of the most important global agreements on climate change, which was formed in order to reduce the emission of greenhouse gases, which is considered the main cause of global warming in recent decades. This protocol obliges only developed countries to reduce greenhouse gas emissions and has exempted developing countries at its time. Also, based on the Paris Agreement, which was signed by the heads of 195 countries of the world, it was determined that greenhouse gas and pollutant emissions due to The serious threat to the planet should be limited even more. Iran has pledged to reduce its greenhouse gas production by 4% by 2030, and by 8% if the sanctions against Iran are completely lifted.

Methodology
In this study, different volume concentration values of gases coming out of the new and traditional heating chimney, including in the heating chimney outlet, were measured in the flow rates of heated gas passing through the station in amounts of 5, 8, and 10,000 cubic meters per hour.MRU OPTIMA 7 device is used to measure the exhaust gases of chimneys, which is equipped with an internal gas analyzer and reads the exhaust gases with an electrochemical method, which has the ability and sensors to measure parameters such as oxygen percentage, reference oxygen, carbon dioxide amount. Carbon monoxide, nitrogen monoxide, nitrogen dioxide, nitrogen oxides, sulfur dioxide, hydrocarbons, hydrogen sulfide, ambient temperature has net combustion efficiency, gross combustion efficiency and Landa coefficient. It was done at three different flow rates for the new and traditional heaters. Sampling time was done for one hour at a constant flow rate when the burners were turned on. The probe of the device was placed in the sampling location and after stabilizing the temperature (decrease fluctuations), the amount of gas output read by the device was recorded.

Conclusion
In this research, the experimental investigation of the pollutants coming out of the new heater installed in the gas pressure reduction station and the comparison of its results with the traditional heater have been done. According to the results obtained by implementing this project at the level of the country's pressure reduction stations, approximately 171,500 cubic meters are saved in the use of heaters during the peak days of gas consumption in winter, and subsequently, the emission of polluting gases is also reduced. It has been shown that there is a decrease in the amount of 32% and a decrease of 22.3% in gas emissions and a decrease of 28.9% in the amount of gas produced, as well as a decrease in the amount of 16.7% and subsequently a decrease in the amount of 20.3%. According to the potential Included in this plan, in addition to saving millions of cubic meters of natural gas per year in the use of heaters, environmental indicators due to the reduction of pollutant emissions are also improved.