Experimental and computational study and development of the bituminous coal entrained-flow air-blown gasifier for IGCC

In the paper the development of the advanced bituminous coal entrained-flow air- blown gasifier for the high power integrated gasification combined cycle is considered. The computational fluid dynamics technique is used as the basic development tool. The experiment on the pressurized entrained-flow gasifier was performed by "NPO CKTI" JSC for the thermochemical processes submodel verification. The kinetic constants for Kuznetsk bituminous coal (flame coal), obtained by thermal gravimetric analysis method, are used in the model. The calculation results obtained by the CFD model are in satisfactory agreements with experimental data. On the basis of the verified model the advanced gasifier structure was suggested which permits to increase the hydrogen content in the synthesis gas and consequently to improve the gas turbine efficiency. In order to meet the specified requirements vapor is added on the second stage of MHI type gasifier and heat necessary for air gasification is compensated by supplemental heating of the blasting air. © Published under licence by IOP Publishing Ltd.This work was financially supported by the Russian Science Foundation (project no. 14-19-00524)

Investigation of coal entrained-flow gasification in O 2 -CO 2 mixtures for oxy-fuel IGCC

Purpose of the study is to obtain fundamental knowledge about Kuznetsk bituminous coal entrained-flow gasification in O 2 -CO 2 mixtures for oxy-fuel IGCC. To achieve this purpose, it is necessary to carry out experimental and numerical studies. To obtain universal knowledge, "CKTI" single-stage gasifier with fuel consumption of 5-15 kg/h was chosen as an experimental installation. In order to identify the most interesting and informative experimental regimes, a number of computational studies have been carried out, whose results are given in the paper. A numerical (CFD) model has been developed, which includes all the submodels necessary for the study. Two series of numerical calculations were carried out. In the first series, the composition of the blast (O 2 = 0-100%, CO 2 = 0-100%) and the oxygen ratio were varied at constant consumption of coal and blast. In the second series, the composition of the blast (O 2 = 0-100%, CO 2 = 0-100%) and the coal consumption were varied at constant oxygen ratio and blast flow rate. The study allowed predicting and analyzing the temperature distribution and the syngas components content along the gasifier height with different CO 2 concentrations in the blast. © 2018 Institute of Physics Publishing. All rights reserved.Russian Foundation for Basic Research (RFBR

Numerical study of the carbon dioxide dissociation influence in oxygen entrained-flow gasifier

One of the energy technologies and resource saving in coal-based energy considered in this work. Namely, entrained-flow gasifier, as a key element of combined-cycle plants with gasification. Numerical modeling of the national plant «NPO CKTI» carried out using computational fluid dynamics (CFD) method. The research of the entrained-flow gasification of solid fuel process was carried out without regard to and with due regard to high-temperature dissociate carbon dioxide process. The researches results of carbon dioxide dissociation process influence in oxygen entrained flow gasifier were described.В работе рассмотрена одна из технологий энерго- и ресурсосбережения в угольной энергетике, а именно поточная газификация твёрдого топлива в газификаторе - ключевом элементе парогазовой установки с внутрицикловой газификацией. Произведено численное моделирование отечественной установки ООО «НПО ЦКТИ» с использованием метода вычислительной гидродинамики CFD. Выполнено исследования процесса поточной газификации твердого топлива без учета и с учетом процесса высокотемпературной диссоциации углекислого газа. Описаны результаты исследования влияния процесса диссоциации углекислого газа в поточном кислородном газификаторе

The numerical research and aerodynamic characteristics comparison of the pilot flow gasifiers

В работе рассмотрена одна из технологий энерго- и ресурсосбережения в угольной энергетике, а именно поточная газификация твёрдого топлива в газификаторе - ключевом элементе парогазовой установки с внутрицикловой газификацией. В докладе сравниваются аэродинамические особенности работы двух пилотных одноступенчатых кислородных газификаторов под давлением с сухой топливоподачей пылевидного твёрдого топлива. Одна из этих установок разработана концерном Siemens, а вторая НПО ЦКТИ. Численное моделирование работы агрегатов проведено с использованием метода вычислительной гидродинамики CFD. Для сокращения времени расчёта геометрия исследуемых газификаторов была упрощена до сегментов в 5 и 45 градусов, соответственно. Произведено исследование расчетной сетки для газификатора Siemens. Сравнение расчётных результатов показало влияние относительных длин камер газификации на расположения аэродинамических структур.One of the energy technologies and resource saving in coal-based energy considered in this work. Namely, flow gasifier, as a key element of combined-cycle plants with nutriciology gasification. In the report the aerodynamic features of the two pilot single-stage pressurized oxygen-blown dry-feed pulverized solid fuels gasifier are compared. One of these units developed by concern Siemens, and the second - NPO CKTI. Numerical modeling of the units carried out using computational fluid dynamics (CFD) method. Simplified segments gasifiers geometries of 5 and 45 degrees, respectively, are studied to reduce the calculation time. The study was conducted of the computational grid for the Siemens gasifier. Comparison of the calculated results showed the influence of the gasification chamber relative lengths on the aerodynamic structures location.Исследование выполнено в Уральском федеральном университете за счет гранта Российского научного фонда (проект №14-19-00524)

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

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)

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