Numerical simulation of nitrogen oxide formation in dust furnaces

Even though natural sources of air pollution account for over 50 % of sulphur compounds, 93 % of nitrogen oxide which are the most dangerous artificial anthropogenic sources of air pollution and primarily associated with the combustion of fossil fuel. Coal-fired thermal power plants and industrial fuel-burning plants that emit large quantities of nitrogen oxides (NО and NО2), solids (ash, dust, soot), as well as carbon oxides, aldehydes, organic acids into the atmosphere pollute the environment in majority. In the present work, a mathematical model and a scheme for calculating the formation of nitrogen oxide has been developed. Also, the dependence of the rate of release of fuel nitrogen from coal particles at the initial stage of gasification and content of volatiles has been obtained. The main regularities of the formation of NOx at the initial section of the flame in the ignition zone of the swirl burner flame during the combustion of Ekibastuz coal have been revealed. Modern environmental requirements for the modernization of existing and the creation of new heat and power facilities determine the exceptional relevance of the development of effective methods and constructions to reduce emissions of nitrogen oxides, sulfur oxides and ash to 200, 300, and 100 mg/nm3 at a=1.4. The dust consumption in all experiments was kept constant and amounted to 0.042 g/s, as well as with the results of calculating the thermal decomposition of the Ekibastuz coal dust, the recombination of atomic nitrogen into nitrogen molecules, and the kinetics of the formation of fuel nitric oxide. It was found that despite the presence of oxygen in Ekibastuz coal for gases Odaf=11.8 % in an inert atmosphere, nitrogen oxides are not formed

Comparative analysis of characteristics of liquid fuel combustion for various designs of oil-steam burners

The paper presents a comparative analysis of experimental data on combustion of liquid hydrocarbon fuels in the presence of superheated steam in two designs of the developed burners. By the example of diesel fuel burnt in a spray burner it is shown that lower values of nitrogen oxide contents in the exhaust gases are achieved in comparison with an evaporative burner. At that, the content of carbon monoxide in some regimes is lower for the evaporative burner. The regimes with the minimum content of toxic combustion products are found for both designs of the burners.

Study of Real-road Nitrogen Oxide Emissions of Non-road Vehicles

The exhaust gas pollutants of the non-road vehicles are harmful to the environment. Many non-road vehicles meet the requirements of the regulations in the laboratory. However, the real-road emissions of such vehicles are sometimes higher. Measuring the real-road emissions of non-road vehicles is very important. The real-road emissions are measured by on-Board Diagnostics (OBD), but there are some problems in the data stability of OBD. The NOx emissions of a bulldozer (a type of China IV non-road vehicle) based on both portable emission measurement system (PEMS) and OBD are studied in this article. Experiments contained three working processes: idle, driving, and operating. The nitrogen oxide (NOx) emissions during operating were highest. The NOx emission characteristics of the bulldozer from PEMS and OBD have the similar variation trends. But there are still some differences, including the NOx emission value and response time. The measurement principles and different sampling points between PEMS and OBD are the main factors. An effective data processing method is introduced to reduce the differences of between the data from PEMS and OBD. Briefly, the NOx emissions of the OBD and PEMS were highly consistent. The OBD is reliable and can be widely used in non-road vehicles.

Oscillating Combustion—Primary Measure to Reduce Nitrogen Oxide in a Grate Furnace–Experiments and Simulations

The emission from industries and the mobility sector is under strong legal regulations in many countries worldwide. In Germany, the amendment to the 17th BlmSchV (Federal pollution control ordinance), which has been in force for waste incineration plants since 2013, has given rise to a new limit for nitrogen oxides of 150 mg/m3 as the daily mean level from 2019 on. A similar focus is on biomass-fired plants. According to the MCP (medium combustion plant) guideline of the EU, as a consequence, existing plants are required to either increase their consumption of ammonia water for nitrogen oxide reduction (SNCR process) or back fit SCR catalysts as secondary measures, which is a costly procedure. This paper presents a novel two-stage process in which an oscillating supply of secondary air allows nitrogen oxides to be reduced by approx. 50% at a good burnout level, which may obviate the need for secondary measures. Besides experimental investigations in a fixed bed reactor, CFD simulations confirm a high potential for reduction of nitrogen oxides. Together with the company POLZENITH, this process is under development for scale-up in a biomass incineration plant as a next step.

Performance, Combustion and Emission Characteristics of a Common Rail Direct Injection Diesel Engine Fueled by Diesel/n-Amyl Alcohol Blends with Exhaust Gas Recirculation Technique

Biofuels are considered as one of the best viable and inexhaustible alternatives to conventional diesel fuel. Alcohols have become very important and popular in the present scenario due to their peculiar fuel properties and production nature. This study examines the effect of n-amyl alcohol and exhaust gas recirculation of 10% and 20% on various engine characteristics of Common Rail Direct Injection (CRDI) compression ignition engine. The proportion of n-amyl alcohol varies from 5% to 25% in 5% step (by volume). The obtained results show that diesel/n-amyl alcohol blends decrease the mean gas temperature and cylinder pressure, which is 1.88% and 4.25% less at 75% load for n-amyl alcohol (25%) with conventional diesel fuel. The duration of combustion has shown a hike of 4.66°CA for 25% n-amyl alcohol (at 75% load) compared to conventional diesel fuel. However, the cumulative heat release rate improved by 12.95% higher for 25% n-amyl alcohol at 75% load, the reason for the same is due to the extended delay in ignition. While n-amyl alcohol was used, the emission of nitrogen oxide emissions decreased considerably. However, the hydrocarbon (HC) (7-9%) and carbon monoxide (CO) (6-8%) emissions are increased due to inferior fuel properties like high latent heat evaporation of n-amyl alcohol. Compared with other blends, n-amyl alcohol (5%) produced results comparable to conventional diesel fuel, which is 3.6% higher in BSFC, 2.37 % higher BTE, and 33.33% higher CO emissions 18.18% more in HC emission, and 17.55% less NOx emission. Without further modification, we can use 25% n-amyl alcohol in the combustion ignition engines. From this evidence, we can summarize that n-amyl alcohol is a biofuel that is both renewable and sustainable, and also it considerably reduces harmful nitrogen oxide emissions. The performance, if needed, can be improved by changing the parameters of the engine.