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[en] A multidimensional simulation of Auxiliary Gas Injection (AGI) for late cycle oxygen enrichment was exercised to assess the merits of AGI for reducing the emissions of soot from heavy duty diesel engines while not adversely affecting the NO(sub x) emissions of the engine. Here, AGI is the controlled enhancement of mixing within the diesel engine combustion chamber by high speed jets of air or another gas. The engine simulated was a Caterpillar 3401 engine. For a particular operating condition of this engine, the simulated soot emissions of the engine were reduced by 80% while not significantly affecting the engine-out NO(sub x) emissions compared to the engine operating without AGI. The effects of AGI duration, timing, and orientation are studied to confirm the window of opportunity for realizing lower engine-out soot while not increasing engine out NO(sub x) through controlled enhancement of in-cylinder mixing. These studies have shown that this window occurs during the late combustion cycle, from 20 to 60 crank angle degrees after top-dead-center. During this time, the combustion chamber temperatures are sufficiently high that soot oxidation increases in response in increased mixing, but the temperature is low enough that NO(sub x) reactions are quenched. The effect of the oxygen composition of the injected air is studied for the range of compositions between 21% and 30% oxygen by volume. This is the range of oxygen enrichment that is practical to produce from an air separation membrane. Simulations showed that this level of oxygen enrichment is insufficient to provide an additional benefit by either increasing the level of soot oxidation or prolonging the window of opportunity for increasing soot oxidation through enhanced mixing
[en] Enthalpies of burning and production of four carborane-containing acetylene peroxides are determined. Methods are used, allowing for incomplete burning of boron-organic compounds. Rectilinear dependences between heat and completeness of burning by carbon, according to which enthalpies under 100% substance burning are calculated, are ascertained
[en] An approach for analysis of the combustion products is suggested on the base of the following assumptions: The system is in thermodynamic equilibrium; No significant dissociation with producing of free N, O, H or, NO, OH takes place at the temperature in the camera and in the same time the temperature is high enough that no significant amount of hydrocarbons (CH4, CH2) are presented; The combustion products consist of gaseous phase. The method is used for calculations of the theoretical temperature of the combustion process for the steam generator P-62 of the 'Maritsa-Iztok 3' TPP. The suggested approach for analysis of the theoretical temperature can be used for the development of a mathematical model of the combustion process at air lack
[en] Combustion modes with a subsurface maximum temperature may occur in the burning of homogeneous energetic materials, such as solid propellants and explosives. In this paper, we analyzed the stability of a stationary combustion wave with a temperature maximum in the condensed phase. We showed that the boundary of stability corresponds to the merging of a stable and unstable solution while the combustion waves with a subsurface temperature maximum can be unsteady only. A dimensionless criterion of the transition to a pulsating mode, which is equal to the ratio of two times: the time of the adiabatic thermal explosion of the subsurface reactive layer and the time of substance depletion due to the combustion front motion, is given. The possible role of a thermal explosion of hotspots in the heated layer during the transition to a hotspot-pulsating combustion mode is discussed.
Research and development of methods and technologies for CO2 capture in fossil fuel power plants and storage in geological formations in the Czech Republic, stage E2: Methods of and technologies for CO2 capture from flue gas and a draft conceptual design of 2 selected variants of a CO2 capture system for a Czech coal fired power plant unit. Final report for Stage 2. Revision 0
[en] The following topics are summarised: Aim and scope of Stage 2. List of research reports developed within Stage 2. Stage 2.1: Methods of and technologies for post-combustion CO2 capture from the flue gas. Status of research and development worldwide. Stage 2.2: Oxyfuel method and technology. Status of research and development worldwide. Stage 2.3: Selection of a chemical absorption based method for post-combustion CO2 separation; and Stage 2.4: Conceptual proposals for a technological solution for the selected chemical absorption based method and for application of the oxyfuel method. (P.A.)
Research and development of methods and technologies for CO2 capture in fossil fuel power plants and storage in geological formations in the Czech Republic, stage E1: Analysis of combustion of O2. Effect of the fuel properties, combustion method and technologies on the flue gas properties. Impacts on the technology of the unit. Final report for Stage 1. Revision 0
[en] The aim of this stage was to examine the properties of the combustion gases in various combustion modes for postulated Czech fuels and to examine the behaviour with respect to heat transfer and requirements for the material; formulate basic conceptual principles for the combustion system and specifically for the boiler with respect to combustion using O2 and mixtures of O2 with recirculated combustion gases; analyse the options and evaluate the optimum O2 use process; and assess the feasible approaches to CO2 purification and compression. Each sub-stage is analysed separately and the UJV reports dealing with the particular sub-stages are identified. (P.A.)
[en] To understand an application of oxygen-enriched incineration (OEI) technology on burnable waste treatment, paper wastes such as copy paper and cleaning paper were burned in OEI process, composed of oxygen/LPG feed system, oxygen-enriched combustion chamber, quencher, filter system, induced fan, water removal condensing system, stack, and off-gas recycle system. The OEI with only pure oxygen reduced off-gas production up to 1 to 3.5 and CO concentration below a half compared to air combustion, while not showing a significant difference in total production of nitrogen oxides
[en] Theoretical analysis was made on the composition and thermodynamic parameters of combustion products of 2,2'-bis(bicyclo[2.2.1]heptane) in oxygen in a wide range of temperatures and pressures. 2,2'-Bis(bicyclo[2.2.1]heptane) can potentially be used as a fuel component in combustion chambers of liquid rocket engines for the first-stage launch vehicles. The average molar mass of approximately 26 amu., obtained for products formed in combustion of 2,2'-bis(bicyclo[2.2.1]heptane) in oxygen is close to similar values for methane in oxygen, whereas its density is more than twice the density of liquid methane. This circumstance makes it possible to hope that the mass of storage tanks can be made smaller if 2,2'-bis(bicyclo[2.2.1]heptane) is used for rockets, compared with the mass of storage tanks containing an equivalent amount of methane. The results obtained can be used to calculate nozzle profiles and combustion chamber parameters of a liquid jet propulsion engines.