The Use of Mechanically Activated Micronized Coal in Thermal Power Engineering

Coal is one of the main energy resources and development of new promising technologies on its basis is certainly topical. This article discusses the use of new technology of gas and fuel oil replacement by mechanically activated micronized coal in power engineering: ignition and stabilization of pulverized coal flame combustion, as well as gasification of micronized coal in the flow. The new technology coal combustion with two stages of grinding is suggested. Optimization of the scheme of two-stage combustion is calculated. The first experimental data on the combustion process are obtained. The first demonstration tests on gas and heavy oil replacement by micronized coal during boiler ignition were carried out in the real power boiler with the capacity of 320 tons of steam per hour

Investigation of hydrodynamic features in two-stage steam-air-blown entrained-flow gasifier

The goal of the work is to study the hydrodynamics features of media movement in IT SB RAS two-stage steam-air-blown entrained-flow gasifier. Analysis of the data obtained using the verified CFD model based on the results of the experiments showed that the conversion process in the mode proceeds in three phases, the localization of which depends on the input mode and design parameters. According to the results of CFD modeling, the injection of relatively cold, weakly superheated steam axial jet into second phases creates hydrodynamic, structural and temperature heterogeneity, which decreases markedly in the third phases. The supplied steam at the second phase performs mainly the functions of a cooler, causing a decrease in the temperature of the reaction mixture and a decrease in the rate of gasification reactions. © 2019 IOP Publishing Ltd.The work was supported by Act 211 02.A03.21.0006

The Effect Of Steam On Air Gasification Of Mechanically Activated Coal In A Flow Reactor

A combined steam-gas plant with in-cycle steam gasification of coal and hot gas purification is considered as a promising technology for increasing the efficiency of energy production with simultaneous reduction in environmental impact. To in-tensify steam-air gasification, mechanical activation of fuel is used; it consists in high-stress grinding in a mill-disintegrator. The supply of steam to the gasifier allows an increase in reactivity of fuel, suppression of sorbent decomposition in the unit of hot desulfurization, reduction in the steam load on the shift reactor, increase in useful external work of gas turbine expansion, reduction in nitrogen oxide formation, and general increase in the efficiency and ecological compatibil-ity of energy generation. On the other hand, a significant amount of steam can deteriorate the heat balance and efficiency of the gasifier. In this work, the influ-ence of the steam/fuel ratio on steam-air gasification of mechanically activated Kuznetsk coal in a flow reactor was studied experimentally. The excess air coeffi-cient was maintained constant and equal to 0.51, which corresponded to a temper-ature at the reactor outlet of about 1100 °C. When steam was supplied, the fuel and air-flow rates were adjusted to ensure a constant gas-dynamic regime. To evaluate the obtained regimes, the heat and material balances were compiled. A positive effect of steam on characteristics of the gasification process was revealed. For the studied coal, the maximum degree of coal conversion and the calorific value of synthesis gas are achieved with a steam/fuel ratio of about 0.4 kg/kg. © 2021 Society of Thermal Engineers of Serbia.Published by the Vinča Institute of Nuclear Sciences, Belgrade, Serbia.This is an open access article distributed under the CC BY-NC-ND 4.0 terms and conditionsResearch results modernization of the experimental stand were obtained within the framework of the state assignment for the IT SB RAS, research results coal gasification was funded by Russian Foundation for Basic Research (project No. 19-38-50071, project No. 18-29-24028)

Effect of steam supply to the air-blown gasifier on hot syngas desulphurization

The IGCC technology serves to efficiently produce thermal and electrical energy with minimal impact on the environment. In operating IGCC, wet desulphurization is used at temperatures below 200°C. The use of hot desulphurization at temperatures around 500°C will significantly improve IGCC efficiency. The preferred sorbent for hot gas cleaning is ZnO. At temperature of 450-500°C, ZnO begins decomposing because of reactions with syngas components (primarily hydrogen). Steam impedes reaction of ZnO with H2 and increases ZnO thermal stability. Syngas H2/H2O ratio is determined by gasifier operation mode. The purpose of this work is to determine maximum temperature of hot gas cleaning depending on condition of ZnO-sorbent thermal stability and steam-air-blown mechanically activated coal gasifier operation mode. To determine the effect of steam supply to syngas composition, experiments were performed on entrained-flow gasifier (1 MW). Experimental results were processed using thermodynamic analysis to determine idealized syngas composition and CFD-modeling to determine real experiment process parameters. Syngas H2O content was determined by CFD-modeling results. Study of ZnO-sorbent thermal stability depending on H2 concentration and syngas H2/H2O ratio was performed by TGA. As a result of experimentally confirmed thermodynamic calculations, ZnO-sorbent thermal stability was found to increase to 815°C due to steam dilution. © Published under licence by IOP Publishing Ltd.The work was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0006

Investigation of multistage air-steam-blown entrained-flow coal gasification

The aim of the work is using an experimental-computational method to study the process of air-steam-blown entrained-flow gasification of coal with multistage air supply. To achieve this aim, the experiment was conducted on a plant consisting of a swirler into which coal and air are supplied, and a reaction chamber into which steam and multistage air are supplied; the experiment was numerically simulated using a validated CFD model; and the process under study was analysed using the obtained experimental and calculated data. The conducted experimental and computational studies of air-steam-blown gasification allowed determining the effect of steam supply and multistage air supply on the features of the gasification process. Steam injection lowers the temperature of the gas mixture and increases the concentration of hydrogen due to the hydrogasification reaction. The air supply to the reaction chamber increases the temperature of the mixture due to the burning of part of the syngas, while the syngas heating value is reduced by an appropriate amount. The maximum concentration of the syngas combustible components (and hence syngas heating value) is observed before the second point of air supply to the reaction chamber. © Published under licence by IOP Publishing Ltd.Experimental studies, development and using of CFD model were performed within the frames of the grant of the Russian Science Foundation (project No. 19-79-00147) (E.B. Butakov, N.A. Abaimov)

INVESTIGATION OF AIR-STEAM-BLOWN TWO-STAGE ENTRAINED-FLOW MECHANICALLY ACTIVATED COAL GASIFICATION

The aim of this study is to determine the effect of steam supply to entrained-flow gasifier of advanced fuel - mechanically activated coal on gasifier operation parameters. Experimental and numerical studies of steam-air-blown gasification of mechanically activated coal made it possible to find dependence of syngas composition and heating value on air stoichiometric factor and steam flow rate. Features of controlling mechanisms of mechanically activated coal gasification are specified.Работа частично выполнена при финансовой поддержке РФФИ, грант № 16-38-50188 (Абаимов Н.А., Бурдуков А.П.)

EXPERIMENTAL AND NUMERICAL STUDIES OF ENTRAINED-FLOW HIGH-TEMPERATURE STEAM-AIR-BLOWN COAL GASIFICATION

The paper considers a method for increasing the energy efficiency of coal power plants using coal gasification technology. The entrained-flow hightemperature steam-air-blown coal gasification in an experimental laboratory gasifier is studied. Using CFD-method the processes taking place in a laboratory unit are investigated.В работе рассмотрен способ повышения энергоэффективности угольных электростанций с использованием технологии газификации угля. Проанализирован процесс поточной высокотемпературной паровоздушной газификации угля в экспериментальном лабораторном газификаторе. С помощью CFD метода исследованы процессы, происходящие в лабораторной установке.Работа выполнена при финансовой поддержке РФФИ, грант № 16-38-5018