Decrease In NOx Emissions Research Articles

A comprehensive organic nitrate chemistry: insights into the lifetime of atmospheric organic nitrates

Abstract. Organic nitrate chemistry is the primary control over the lifetime of nitrogen oxides (NOx) in rural and remote continental locations. As NOx emissions decrease, organic nitrate chemistry becomes increasingly important to urban air quality. However, the lifetime of individual organic nitrates and the reactions that lead to their production and removal remain relatively poorly constrained, causing organic nitrates to be poorly represented by models. Guided by recent laboratory and field studies, we developed a detailed gas-phase chemical mechanism representing most of the important individual organic nitrates. We use this mechanism within the Weather Research and Forecasting (WRF) model coupled with Chemistry (WRF-Chem) to describe the role of organic nitrates in nitrogen oxide chemistry and in comparisons to observations. We find the daytime lifetime of total organic nitrates with respect to all loss mechanisms to be 2.6 h in the model. This is consistent with analyses of observations at a rural site in central Alabama during the Southern Oxidant and Aerosol Study (SOAS) in summer 2013. The lifetime of the first-generation organic nitrates is ∼2 h versus the 3.2 h lifetime of secondary nitrates produced by oxidation of the first-generation nitrates. The different generations are subject to different losses, with dry deposition to the surface being the dominant loss process for the second-generation organic nitrates and chemical loss being dominant for the first-generation organic nitrates. Removal by hydrolysis is found to be responsible for the loss of ∼30 % of the total organic nitrate pool.

Multi-objective optimization of diesel engine performance and emissions fueled with diesel-biodiesel-fusel oil blends using response surface method.

The interest in research on alcohol-based biofuels is on the rise. Fusel oil is a long-chain alcohol and a by-product of bioethanol synthesis. This study analyzed the effects of blended levels of fusel oil and biodiesel in diesel fuel on the performance and exhaust emissions of a single-cylinder diesel engine. The effects of input parameters (i.e., fusel oil content (%), biodiesel content (%), engine speed (rpm), and engine load (%), each at five levels) on response parameters (i.e., power, torque, fuel consumption, and emission factors, namely NOX, UHC, CO, and CO2) were investigated. Different levels were used for analyzing fusel oil (0, 5, 10, 15, and 20%), biodiesel (0, 5, 10, 15, and 20%), engine load (0, 25, 50, 75, and 100%), and engine speed (1400, 1700, 2000, 2300, and 2600rpm). Response surface method (RSM) was employed to maximize engine performance and minimize exhaust emissions. A blend of D90F5 B5 (5% fusel oil, 5% biodiesel, and 90% petro-diesel) and engine speed of 2026rpm at load 46% were predicted to be an optimal value. Using a 72% desirability function, optimum results for torque (14.2Nm), power (3.37kW), and brake-specific fuel consumption (356.9g/kWh) were also obtained from RSM. Based on the optimized inputs, the optimized values of different output pollutants were 0.14 vol.% for CO, 1.62 vol.% for CO2, 23.7ppm for UHC, and 85.17ppm for NOX. The result illustrated that use of fusel oil decreased NOX emissions up to 20%, while UHC and CO emissions increased up to 32% and 22%, respectively. In addition, the use of fusel oil content (up to 10%) in the blended fuels improved the engine power by 5.6%.

Comparative studies on combustion, performance and emission characteristics of a two-wheeler with gasoline and 30% ethanol-gasoline blend using chassis dynamometer

Mid-level ethanol-gasoline blends such as E30 offers significant advantages in terms of higher octane number, desirable Reid vapor pressure and water tolerance characteristics compared to lower blends. An experimental study was undertaken on a motorcycle with commercial gasoline (E0) and 30% ethanol blended gasoline (E30) using a chassis dynamometer. Combustion, performance and emissions characteristics were investigated under steady state (wide-open throttle – WOT) and transient (Indian driving cycle – IDC) operating conditions. In the WOT test, carbon monoxide and hydrocarbon emissions decreased however oxides of nitrogen (NOx) increased with E30 compared to E0. The specific fuel consumption was higher with E30 but vehicle power decreased. Combustion analysis showed an increased combustion duration and delay in heat release rate with E30. The peak combustion pressure and maximum rate of pressure rise were also lower. Mass emission studies over IDC test show a decrease in CO and NOx emissions with E30 while hydrocarbon emission increased marginally. The notable point emerged from the study is that the operating conditions and change in air-fuel mixture regime impact the performance and emissions of two-wheeler significantly. The present work provides useful information for designing a dedicated spark ignition engine suitable for mid-level ethanol blends.

Experimental Study on Combustion Adjustment for Dense-dilute Burning through Swirling Burner with Variable Flaring Angle

A swirling burner with adjustable inner secondary air flaring angle is proposed and a laboratory-scale opposed-firing furnace is built. The effects of burner flaring angle on dense-dilute low-NOx burning are experimentally studied. The temperature distributions along the depth and height direction of furnace are emphatically illustrated. NOx emission and char burnout are compared and discussed. Experiment results indicate that under the dense-dilute burning conditions, variation of burner inner secondary air flaring promotes ignition conditions. Under different conditions of dense-dilute ratio, variation of burner flaring angle can help decreasing NOx emission and improving char burnout. Finally the optimum flaring angle of swirling burner under different dense-dilute ratios is summarized in the form of curves, which could provide reference for exquisite and novel combustion adjustment.

A novel fuel containing glycerol triacetate additive, biodiesel and diesel blends to improve dual-fuelled diesel engines performance and exhaust emissions

Declining petroleum sources and increasing demands for energy and emissions characteristics of fossil fuels combustion lead investigations to clean, available and low-cost energy resources. Dual-fuelled diesel engine by NG as main fuel and biodiesel blend as pilot fuel can be an appreciate idea to reduce engine emissions and using renewable source of fuel. The main aim of present study is to use the blend of glycerol triacetate (GT) additive and biodiesel to reduce emissions and to improve fuel cost of dual-fuelled diesel engine by natural gas as main fuel. Tests performed on dual fueled, constant speed (1500 rpm) diesel engine by two levels of biodiesels (B5, B20) with three levels of GT additives (3%, 5%, 7%) and neat diesel fuel as pilot fuel and four levels of pilot fuel to gaseous fuel (20%, 30%, 40%, 50%). Based on results, using B5A3 as pilot fuel decreased NOx emission by 24% in pilot-to-gaseous (P/G) fuel ratio of 50%. Using B20A3 as pilot fuel significantly reduced PM emission, such that in P/G ratio of 20% it was 85% lower than that of diesel as pilot fuel. CO emission was found to be 72% lower than that of diesel as pilot fuel in case of using B5A7 as pilot fuel in P/G ratio of 20%. Using B5 as pilot fuel in P/G ratio of 20% reduced CO2 emission by about 8% compared to that of diesel as pilot fuel. UHC emission had been increased slightly using biodiesel and GT additive rather than diesel pilot fuel. It was also observed that in the P/G ratio of 40% using B5 fuel, the GP cost was 0.22 $/kWh which is about 15% lower than that for diesel pilot fuel.

Effect of fuel injection strategies on the performance of the common rail diesel injection (CRDI) engine powered by biofuel

ABSTRACT The effects of fuel injection strategies on the characteristics of common rail diesel injection engine using mahua methyl ester (MME20) blend have been investigated. Fuel injection strategies such as fuel pressure and split injection have been implemented on a test engine. When MME20 was used as the fuel on mechanical injection at an injection pressure of 22 MPa, specific fuel consumption and NOx emission were found to be increased and brake thermal efficiency (BTE) decreased. In the first phase, in order to optimise the utilisation of the mahua methyl ester blend, fuel injection pressure was increased from 20 to 50 MPa with an increment of 10 MPa. The experimental observation reveals that high fuel injection pressure (50 MPa) exhibits higher BTE and better combustion characteristics when compared with decremented injection pressures. HC, CO and smoke level decreased with an increase in injection pressure due to better-atomised spray and mixture formation. In the second phase, implementation of spilt injection 5% MME20 as pilot injection at 5°, 10° and 15° CA before main injection was identified with the decrease of HC, CO, NOx and smoke emission with marginal sacrifice of BTE compared with diesel fuel.

Experimental study on combustion, flame and NOX emission of pulverized coal preheated by a preheating burner

Experimental researches on combustion characteristics of pulverized Ningdong bitumite preheated by a preheating burner were carried out in a 0.2 MW coal preheating combustion test rig, and the effects of preheating temperature, secondary air equivalence ratio and the positions of tertiary air nozzles on combustion, flame and NOX emissions of preheated fuels were studied. The results showed that the 0.2 MW coal preheating combustion test rig can operate stably and the combustion efficiency can be higher than 97% while the NOX emissions are lower than 100 mg/Nm3. With the increase of preheating temperature, NOX emissions increase, and the combustion efficiency does not change obviously. With the increase of secondary air equivalence ratio, the combustion efficiency increases, and NOX emissions increase as well. With the increase of the distance between the tertiary air nozzle and the preheated fuel nozzle, NOX emissions decrease, and the combustion efficiency decreases as well. The flame characteristic is not sensitive to preheating temperature, but closely related to the air distribution of down-fired combustor. With reasonable air supply positions, flameless combustion can be realized.

Thermoenvironomic evaluation of simple, intercooled, STIG, and ISTIG cycles

Low-technology cycle modifications available for improving gas turbine performance are still largely unexploited. Among those proven modifications, steam injection is found to be the most effective in boosting both the output capacity and thermal efficiency while reducing NOx emissions. It further improves part load performance under varying ambient conditions. Intercooling is another low-technology modification which can improve performance of simple and steam injected gas turbine cycles. Because of the uncertainties relating to an efficiency comparison of steam injected and simple cycle designs, the decision as to whether it is worthwhile to give more emphasis to steam injected cycles should be made on grounds other than efficiency alone. Therefore, this study comparatively evaluates simple, intercooled, steam injected (STIG), and intercooled steam injected (ISTIG) gas turbine cycles from the points of efficiency, network output, economics, and pollutant emissions using an advanced validated thermoenvironomic model. Optimum cycle parameters are investigated. Economic feasibility of steam injection and intercooling on simple and intercooled cycles are evaluated using an updated plant cost data. Total and environmental costs as well as profit of the plant owner are estimated for varying fuel costs and varying cycle parameters such as pressure, steam injection, and equivalence ratio. Results of our analysis based on the characteristic cycle parameters show that network output increases up to 22.2% and 14% respectively, when steam injection is implemented on simple and intercooled gas turbine cycles which correspond to up to 6.7% and 4.4% decrease in specific fuel consumption. Steam injection decreases NOx emissions of simple and intercooled cycles up to 67.2% and 65.2% respectively, and provides up to approximately 126.3% increase in net profit of intercooled cycle at the expense of an increase in total cost by 3.3%.

Effects of various split injection strategies on combustion and emissions characteristics in a single-cylinder diesel engine

The purpose of this study is to investigate combustion and exhaust emissions characteristics by applying various split-injection strategies in order to determine the optimal injection that improves fuel efficiency and reduces exhaust emissions, compared with single-injection combustion. The split-injection strategies, such as the change of injection pressure, injection timing, and injection interval, were applied to single-cylinder diesel engine.From the analysis of the experimental results, it was revealed that, when the injection pressure was increased without changing the injection timing in split injection, indicated mean effective pressure (IMEP) and brake mean effective pressure (BMEP) decreased and brake specific fuel consumption (BSFC) deteriorated, owing to the increase of dwell duration. The increase of injection interval induced deterioration of BSFC and caused an increase in NOx and HC emissions with significant reduction in CO and soot emissions. On the other hand, the retardation of injection timing with a fixed injection interval caused an improvement of the BSFC, and a decrease in NOx, CO, and HC emissions. However, soot emission increased. According to the analysis, a short injection interval and injection timing around top dead center (TDC), with not too high injection pressure, improve the BSFC and emission characteristics in split-injection diesel combustion.

Full-Scale Demonstration of Enzyme-Treated Coal Combustion for Improved Energy Efficiency and Reduced Air Pollution

The application of a new biochemical combustion technology, using a nanoenzyme (3EC) product, was studied in a 450 MW power plant. The enzyme changes the structure of the coal during the treatment process. The boiler performance and amount of air pollution were measured and analyzed. There was a clear decrease in the slagging observed on the heat-exchanger tubes. This is attributed to the formation of a softer, more porous iron-containing aluminosilicate slag structure. As a result, the slag does not cling to the heat-exchange tubes as tightly. Burning the enzyme-treated coal resulted in a decrease in NOx emissions by 16.72–21.43% during the entire test period and a decrease in SO2 emissions by 5.42–7.31% during the 85% load condition compared to emissions from the raw coal tests. In addition, sub-micrometer particles and mercury distribution were also influenced by the enzyme.

The Impact of Predried Lignite Cofiring With Hard Coal in an Industrial Scale Pulverized Coal Fired Boiler

The paper presents the experimental and numerical study on the behavior and performance of an industrial scale boiler during combustion of pulverized bituminous coal with various shares of predried lignite. The experimental measurements were carried out on a boiler WP120 located in CHP, Opole, Poland. Tests on the boiler were performed during low load operation and the lignite share reached over to 36% by mass. The predried lignite, kept in dedicated separate bunkers, was mixed with bituminous coal just before the coal mills. Computational fluid dynamic (CFD) simulation of a cofiring scenario of lignite with hard coal was also performed. Site measurements have proven that cofiring of a predried lignite is not detrimental to the boiler in terms of its overall efficiency, when compared with a corresponding reference case, with 100% of hard coal. Experiments demonstrated an improvement in the grindability that can be achieved during co-milling of lignite and hard coal in the same mill, for both wet and dry lignite. Moreover, performed tests delivered empirical evidence of the potential of lignite to decrease NOx emissions during cofiring, for both wet and dry lignite. Results of efficiency calculations and temperature measurements in the combustion chamber confirmed the need to predry lignite before cofiring. Performed measurements of temperature distribution in the combustion chamber confirmed trend that could be seen in the results of CFD. CFD simulations were performed for predried lignite and demonstrated flow patterns in the combustion chamber of the boiler, which could prove useful in case of any further improvements in the firing system. CFD simulations reached satisfactory agreement with the site measurements in terms of the prediction of emissions.

Modeling NH4NO3 Over the San Joaquin Valley During the 2013 DISCOVER-AQ Campaign.

The San Joaquin Valley (SJV) of California experiences high concentrations of particulate matter NH4NO3 during episodes of meteorological stagnation in winter. A rich data set of observations related to NH4NO3 formation was acquired during multiple periods of elevated NH4NO3 during the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field campaign in SJV in January and February 2013. Here NH4NO3 is simulated during the SJV DISCOVER-AQ study period with the Community Multiscale Air Quality (CMAQ) model, diagnostic model evaluation is performed using the DISCOVER-AQ data set, and integrated reaction rate analysis is used to quantify HNO3 production rates. Simulated NO3- generally agrees well with routine monitoring of 24-hr average NO3-, but comparisons with hourly average NO3- measurements in Fresno revealed differences at higher time resolution. Predictions of gas-particle partitioning of total nitrate (HNO3 + NO3-) and NHx (NH3 + NH4+) generally agree well with measurements in Fresno, although partitioning of total nitrate to HNO3 is sometimes overestimated at low relative humidity in afternoon. Gas-particle partitioning results indicate that NH4NO3 formation is limited by HNO3 availability in both the model and ambient. NH3 mixing ratios are underestimated, particularly in areas with large agricultural activity, and additional work on the spatial allocation of NH3 emissions is warranted. During a period of elevated NH4NO3, the model predicted that the OH + NO2 pathway contributed 46% to total HNO3production in SJV and the N2O5 heterogeneous hydrolysis pathway contributed 54%. The relative importance of the OH + NO2 pathway for HNO3 production is predicted to increase as NOx emissions decrease.

NOx emission of biodiesel compared to diesel: Higher or lower?

A little decrease in NOx emission of biodiesel compared to diesel is observed at low loads under low and medium engine speeds. An overall experimental investigation on NOx emission based on combustion characteristics of biodiesel has been carried out. Negative effects of high viscosity and distillation temperature on the spray quality and homogeneity of air fuel mixture are clear at low loads under low and medium speeds. Brake thermal efficiency (BTE) and combustion temperature of biodiesel are lower than those of diesel, resulting in a lower level of NOx emission. With the increase of load, in-cylinder thermal condition and the injection pressure are improved, and with the increase of speed, air swirl movement is strengthened. Oxygenated biodiesel produces more reactive radicals than diesel, and these radicals will surely accelerate the combustion speed, improves the intensity of diffusion combustion, shortens the combustion duration and increase the BTE. Consequently, the diffusion combustion temperature, especially the peak combustion temperature of biodiesel is higher than that of diesel. On the whole, NOx emission of biodiesel is higher than that of diesel in most cases, except in the condition of low loads under low and medium speeds.

Role of fuel additives on reduction of NOX emission from a diesel engine powered by camphor oil biofuel.

The present study intends to explore the effect of the addition of fuel additives with camphor oil (CMO) on the characteristics of a twin-cylinder compression ignition (CI) engine. The lower viscosity and boiling point of CMO when compared to diesel could improve the fuel atomization, evaporation, and air/fuel mixing process. However, thelower cetane index of CMO limits its use as a drop in fuel for diesel in CI engine. In general, NOX emission increases for less viscous and low cetane (LVLC) fuels due to pronounced premixed combustion phase. To improve the ignition characteristics and decrease NOX emissions, fuel additives such as diglyme (DGE)-a cetane enhancer, cumene (CU)-an antioxidant, and eugenol (EU) and acetone (A)-bio-additives, are added 10% by volume with CMO. The engine used for the experimentation is a twin-cylinder tractor engine that runs at a constant speed of 1500rpm. The engine was operated with diesel initially to attain warm-up condition, which facilitates the operation of neat CMO. At full load condition, brake thermal efficiency (BTE) for CMO is higher (29.6%) than that of diesel (28.1%), while NOX emission is increased by 9.4%. With DGE10 (10% DGE + 90% CMO), the ignition characteristics of CMO are improved and BTE is increased to 31.7% at full load condition. With EU10 (10% EU + 90% CMO) and A10 (10% A + 90% CMO), NOX emission is decreased by 24.6 and 17.8% when compared to diesel, while BTE is comparable to diesel. While HC and CO emission decreased for DGE10 and CU10, they increased for EU10 and A10 when compared to baseline diesel and CMO.

Numerical and experimental investigations of the effects of the second injection timing and alcohol-gasoline fuel blends on combustion and emissions of an HCCI-DI engine

In this study, experimental and numerical investigations of a homogeneous charge compression ignition (HCCI) combustion engine were performed using alcohol-gasoline fuel blends and two-stage direct injection (TSDI) strategy. A diesel engine was modified to operate as an electronically controlled HCCI-DI engine. TSDI strategy was applied by fixing the first injection timing in intake stroke and varying the second injection timing close to the compression top dead center (TDC). The selected fuels were pure gasoline and four different blends of ethanol and methanol with gasoline, namely E10, E20, M10 and M20. The effects of the second injection timing and alcohol-gasoline fuel blends on the HCCI combustion and emissions were investigated at constant engine speed and high equivalence ratio for the same energy input. CFD simulations were performed using AVL Fire code and CFD results were compared with the experimental results of the HCCI-DI engine. Cylinder gas pressure, rate of heat release (ROHR), maximum cylinder gas temperature, CO and NOx emissions were investigated numerically. Visual information about the in-cylinder temperature distribution and NOx emissions were provided from images taken from the CFD model. It can be understood from both experimental and CFD studies that combustion phase can be most effectively controlled by changing the second fuel injection timing for all fuel blends. Adding alcohol to gasoline helped to decrease NOx emissions while keeping the maximum cylinder gas pressure stable compared to pure gasoline.

Parametric Computational Studies to Decrease NO x Emissions in Combustion of an Ideal Fuel Air Mixture with Management of Several Stabilization Zones1

The present article is the first of a series of articles concerned with computational studies on optimization of the process of combustion of a fuel air mixture with temperatures of the gases at the exit from the combustion chamber of around 1600°C where the emission requirements are satisfied. Results of calculations of the combustion of an ideally mixed fuel air mixture in a combustion chamber of typical design possessing several flame stabilization zones formed by swirling of the flows of two swirl nozzles and sudden expansion of the flow in the space of a flue tube are presented. The influence of the position and form of the flame, the concentration and the different variants in which the fuel air mixture is fed into the combustion chamber, the input temperature, preheating in the combustion chamber, swirling of the flow, occupation time, and the pressure and mass of the recirculated flow on the formation of nitric oxides and the completeness of combustion is investigated. Dependences of NO x emission on different influencing factors are obtained. Using the results obtained we are able to estimate the minimally possible level of nitric oxide emissions attainable with a standard optimized design of single-zone combustion of an ideally mixed fuel air mixture. A further decrease in NO x emissions is possible through the creation of two or more sequential zones of fuel afterburning in a depleted oxygen-based oxidant. The form and position of the front of the flame and the completeness and length of combustion of the fuel as a function of the above factors, enabled by varying the design of the combustion chamber while maintaining stable and complete combustion of the fuel, are investigated.

Remote sensing of methane and nitrous oxide fluxes from waste incineration

Incomplete combustion processes lead to the formation of many gaseous byproducts that can be challenging to monitor in flue gas released via chimneys. This study presents ground-based remote sensing approaches to make greenhouse gas (GHG) flux measurements of methane (CH4) and nitrous oxide (N2O) from a waste incineration chimney at distances of 150–200 m. The study found emission of N2O (corresponding to 30–40 t yr−1), which is a consequence of adding the reduction agent urea to decrease NOX emissions due to NOX regulation; a procedure that instead increases N2O emissions (which is approximately 300 times more potent as a GHG than CO2 on a 100-year time scale). CH4 emissions of 7–11 t yr−1 was also detected from the studied chimney despite the usage of a high incineration temperature. For this particular plant, local knowledge is high and emission estimates at corresponding levels have been reported previously. However, emissions of CH4 are often not included in GHG emission inventories for waste incineration. This study highlights the importance of monitoring combustion processes, and shows the possibility of surveying CH4 and N2O emissions from waste incineration at distances of several hundred meters.

Simultaneous Application of Exhaust Gas Recirculation and Non-Constant Injection Rates to Reduce NOx and Soot Emissions in Diesel Engines

A combination of EGR and variation of injection rate has been used to keep both NOx and soot emissions at an acceptable level. To do so, a two-dimensional multi-zone phenomenological diesel engine combustion model has been developed. The model consists of several sub-models for spray development, fuel atomization, evaporation, combustion, and emission formation. The fuel spray is divided into several small packets called zones, and consequently, the equations for conservation of mass and energy are solved for each individual zone at each time step, from which the cylinder temperature and pressure are calculated. Additionally, the formation of emissions is tracked as soon as the combustion starts. Moreover, parallel processing programming techniques have been utilized, which reduce the computational time of the model considerably, making it a fast and reliable tool for combustion simulation. Using the model, different rates of EGR are applied, which as expected shows a noticeable decrease in NOx emissions. Thanks to the modular design of the model, injection profile can be changed easily. Instead of using a constant rate injection, three different injection patterns are used. First, an upward step profile is used, in which fuel is initially injected with a lower and then with a higher rate. After that, a downward step profile was applied, which injects the fuel first with a lower and then a higher rate. Finally, a combination of the above profiles is used, i.e., the fuel is injected initially at a low rate, and then, the injection rate is increased, and finally decreased again. It is shown that use of EGR with a combined injection pattern at the same time can keep the NOx and soot emissions of the diesel engine at an acceptable level.

Experimental analysis of the influence of coolant and oil temperature on combustion and emissions in an automotive diesel engine

Since many trips are of short duration and include a cold start, automotive engines run quite often without having reached their nominal temperature. This is known to have some major drawbacks, such as increased fuel consumption and higher emissions due to lower efficiency of after-treatment devices, but detailed description of these various effects is seldom presented in the literature. In this article, experiments were conducted on an automotive diesel engine by varying independently the coolant and oil temperatures between 30 °C and 90 °C. Three different operating conditions (low, mid and full load) were studied. The experimental set-up is briefly described as well as the uncertainty of the associated measurements and the development of analytic tools. Then, the evolution of volumetric efficiency, energy share, combustion heat release and exhaust emissions (NOx, particulate matter, CO, unburned hydrocarbons) are described in detail and analysed. Several strategies were considered, including some corrections used in the standard engine control unit to compensate for the low coolant temperature. Some effects of the coolant and oil temperature reduction were clear: increase in friction losses, volumetric efficiency and ignition delay and decrease in NOx emissions. On the contrary, the evolution of brake thermal efficiency, particulate matter, CO and unburned hydrocarbon emission depended on the operating point.

The study on decreasing of nitrogen oxides emission carried out on DKVR 10-13 industrial heating boilers

Nitrogen oxides are considered to be much more toxic than, for example, carbon monoxide. For this reason, the Authors developed and implemented a method for decrease of NOX emission into the atmosphere from DKVR 10-13 boilers. As an effective method for boilers propose injection of steam into the combustion zone. After series of experimental studies an optimal design of the head for steam injection was developed, according to the proprietary technology. The injector head was kept unchanged while the spraying end caps were modified (Fig. 2). Three levels of possible impact of emissions from boiler on the atmosphere pollution were taken into account during studies. After the analysis, it was assumed that the level of the real maximum emission should be taken as the reference level in relation to which the decrease of NOX emission should be determined. The results obtained by the Authors calculated into mass emission and as objective values of nitrogen oxides concentration calculated into α = 1 (Figures 3 and 4). Realization of the study plan, assumed by the Authors, allowed to determine the optimal parameters of the NOx emission decrease method, assuming the expected 30% level of emission decrease at a limited consumption of injected.