Oxides of nitrogen from coal-fired power stations are considered to be major pollutants, and there is increasing concern for regulating air quality and offsetting the emissions generated from the use of energy. Reburning is an in-furnace, combustion control technology for NOx reduction. Another environmental issue that needs to be addressed is the rapidly growing feedlot industry in the United States. The production of biomass from one or more animal species is in excess of what can safely be applied to farmland in accordance with nutrient management plans and stockpiled waste poses economic and environmental liabilities. In the present study, the feasibility of using biomass as a reburn fuel in existing coal-fired power plants is considered. It is expected to utilize biomass as a low-cost, substitute fuel and an agent to control emission. The successful development of this technology will create environment-friendly, low cost fuel source for the power industry, provide means for an alternate method of disposal of biomass, and generate a possible revenue source for feedlot operators. In the present study, the effect of coal, cattle manure or feedlot biomass, and blends of biomass with coal on the ability to reduce NOx were investigated in the Texas A&M University 29.31 kW (100,000 Btu/h) reburning facility. The facility used a mixture of propane and ammonia to generate the 600 ppm NOx in the primary zone. The reburn fuel was injected using air. The stoichiometry tested were 1.00 to 1.20 in the reburn zone. Two types of injectors, circular jet and fan spray injectors, which produce different types of mixing within the reburn zone, were studied to find their effect on NOx emissions reduction. The flat spray injector performed better in all cases. With the injection of biomass as reburn fuel with circular jet injector the maximum NOx reduction was 29.9 % and with flat spray injector was 62.2 %. The mixing time was estimated in model set up as 936 and 407 ms. The maximum NOx reduction observed with coal was 14.4 % and with biomass it was 62.2 % and the reduction with blends lay between that of coal and biomass.

Oxides of nitrogen from coal-fired power stations are considered to be major pollutants, and there is increasing concern for regulating air quality and offsetting the emissions generated from the use of energy. Reburning is an in-furnace, combustion control technology for NOx reduction. Another environmental issue that needs to be addressed is the rapidly growing feedlot industry in the United States. The production of biomass from one or more animal species is in excess of what can safely be applied to farmland in accordance with nutrient management plans and stockpiled waste poses economic and environmental liabilities. In the present study, the feasibility of using biomass as a reburn fuel in existing coal-fired power plants is considered. It is expected to utilize biomass as a low-cost, substitute fuel and an agent to control emission. The successful development of this technology will create environment-friendly, low cost fuel source for the power industry, provide means for an alternate method of disposal of biomass, and generate a possible revenue source for feedlot operators. In the present study, the effect of coal, cattle manure or feedlot biomass, and blends of biomass with coal on the ability to reduce NOx were investigated in the Texas A&M University 29.31 kW (100,000 Btu/h) reburning facility. The facility used a mixture of propane and ammonia to generate the 600 ppm NOx in the primary zone. The reburn fuel was injected using air. The stoichiometry tested were 1.00 to 1.20 in the reburn zone. Two types of injectors, circular jet and fan spray injectors, which produce different types of mixing within the reburn zone, were studied to find their effect on NOx emissions reduction. The flat spray injector performed better in all cases. With the injection of biomass as reburn fuel with circular jet injector the maximum NOx reduction was 29.9 % and with flat spray injector was 62.2 %. The mixing time was estimated in model set up as 936 and 407 ms. The maximum NOx reduction observed with coal was 14.4 % and with biomass it was 62.2 % and the reduction with blends lay between that of coal and biomass.

One major aspect of environmental pollution affecting human life and climate is air pollution. The harmful pollutants in the air include mostly hydrocarbons, carbon monoxide, carbon dioxide, nitrogen oxides as well as soot and other particulate matter. These pollutants result in several damaging effects on environment and living beings which include acid rain, photochemical smog, global warming and various health hazards in human beings even cancer. Major contribution of these pollutants is from man-made sources such as industrial and automotive emissions that employ fossil fuels. In our country, diesel constitutes more than 40% of the fossil fuel consumption. Studies show that diesel engine emissions contribute to 80% of nitrogen oxides amongst other air pollutants. In the context of stringent emission regulations being implemented all over the world, exhaust emission control, in general and nitrogen oxide emission in particular, is gaining significant importance. A review of recent literature indicates the significance and popularity of electrical discharge based non thermal plasma for exhaust cleaning applications in general, and NOx cleaning in particular. While the existing pre-combustion and catalyst based post-combustion nitrogen oxides (NOx) abatement techniques have inherent disadvantages owing to short shelf life, saturated engine modifications, cost concerns etc., the electrical discharge based non- thermal plasma techniques offer certain advantages in terms of cost and life factors. Several non-thermal plasma techniques viz., pulsed plasma, surface plasma, dielectric barrier discharge plasma etc., have been studied under different laboratory conditions. Interestingly, due to the high oxidizing environment that prevails in the discharge plasma zone, complete reduction of NOx by the plasma alone is becoming a challenging task. This has led the researchers to utilize additional processing techniques in cascade with discharge plasma. This additional gas cleaning technique may involve the use of adsorbents, catalysts or some other secondary treatment for eliminating the nitrogen oxides produced due to oxidizing reactions in the plasma chamber. One such additive can be an adsorbent, which can be commercially obtained or prepared from industrial wastes. In this thesis the adsorption properties of two industrial wastes were explored for the first time in conjunction with discharge plasma. The synergistic effect of plasma combined with an adsorbent shows promising results in NOx removal thus offering an effective solution to two environmental issues namely air pollution and open waste dumping. While the plasma, generally, refers to direct plasma treatment of exhaust, it can also be used for generation of ozone in a separate reactor which can subsequently be injected into the exhaust stream resulting in indirect plasma treatment. The current work focuses on both direct and indirect dielectric barrier discharge plasma treatment for NOx reduction in diesel engine exhaust cascaded with either oyster shells, a mariculture waste or lignite ash from lignite coal fired plant. Instead of conventional petro-diesel, biodiesel produced from the seeds of pongamia pinnata is used as the fuel. This biofuel, on one hand, causes considerable reduction in volatile organic compounds, particulate matter, soot, oil mist etc., but on the other hand may have higher concentrations of nitrogen oxides, an aspect that has motivated us to take up the research work envisaged in this thesis. It was observed in the laboratory environment that for a given power, both direct and indirect plasma treatments have resulted in NOx removal to the tune of 85 to 95% when cascaded with the adsorbents studied.

The aim of this thesis is the proposal of a coal mill system and a combustion chamber for the boiler PK 4S situated in Košice CHP station with regard to transition to the new fuel. This proposal is focused on the elimination of NOx emissions. The calculation is based on required parameters of the boiler and declared characteristic of the new fuel. The proposal of the coal mill system includes three roller mills working in closed circuit with direct blowing. One of the mills serves as a reserve in case of failure. Dimensions of the dry bottom combustion chamber are proposed considering the applied primary measures to reduce NOx emissions so that the temperature at the end of the furnace would not be higher than maximal allowed temperature 1200 °C.

The subject of this study is the effect of in-cylinder selective non-catalytic reduction (SNCR) of NOx emissions in diesel exhaust gas by means of direct injection of aqueous urea ((NH2)2CO) into the combustion chamber. A single cylinder diesel test engine was modified to accept an electronically controlled secondary common rail injection system to deliver the aqueous urea directly into the cylinder during engine operation. Direct in-cylinder injection was chosen in order to ensure precise delivery of the reducing agent without the risk of any premature reactions taking place. Unlike direct in-cylinder injection of neat water, aqueous urea also works as a reducing agent by breaking down into ammonia (NH3) and Cyanuric Acid ((HOCN)3). These compounds serve as the primary reducing agents in the NOx reduction mechanism explored here. The main reducing agent, aqueous urea, was admixed with glycerol (C3H8O3) in an 80-20 ratio, by weight, to function as a lubricant for the secondary injector. The aqueous urea injection timing and duration is critical to the reduction of NOx emissions due to the dependence of SNCR NOx reduction on critical factors such as temperature, pressure, reducing agent to NOx ratio, Oxygen and radical content, residence time and NH3 slip. From scoping engine tests at loads of 40 percent and 80 percent at 1500 rpm, an aqueous urea injection strategy was developed. The final injection strategy chosen was four molar ratios, 4.0, 2.0, 1.0 and 0.5 with five varying injection timings of 60, 20, 10, 0, and -30 degrees after top dead center (ATDC). In addition to the base line and aqueous urea tests, water injection and an 80-20 water-glycerol solution reduction agent tests were also conducted to compare the effects of said additives as well. The comparison of baseline and SNCR operation was expected to show that the urea acted as a reducing agent, lowering NOx emissions up to 100% (based on exhaust stream studies) in the diesel exhaust gas without the aid of a catalyst. The data collected from the engine tests showed that the aqueous urea-glycerol solution secondary had no effect on the reduction of NOx and even resulted in an increase of up to 5% in some tests. This was due to the low average in-cylinder temperature as well as a short residence time, prohibiting the reduction reaction from taking place. The neat water and water-glycerol solution secondary injection was found to have a reduction effect of up to 59% on NOx production in the emissions due to the evaporative cooling effect and increased heat capacity of the water.