Development of advanced air-blown entrained-flow two-stage bituminous coal IGCC gasifier

Integrated gasification combined cycle (IGCC) technology has two main advantages: high efficiency, and low levels of harmful emissions. Key element of IGCC is gasifier, which converts solid fuel into a combustible synthesis gas. One of the most promising gasifiers is air-blown entrained-flow two-stage bituminous coal gasifier developed by Mitsubishi Heavy Industries (MHI). The most obvious way to develop advanced gasifier is improvement of commercial-scale 1700 t/d MHI gasifier using the computational fluid dynamics (CFD) method. Modernization of commercial-scale 1700 t/d MHI gasifier is made by changing the regime parameters in order to improve its cold gas efficiency (CGE) and environmental performance, namely H2/CO ratio. The first change is supply of high temperature (900°C) steam in gasifier second stage. And the second change is additional heating of blast air to 900°C. © The authors, published by EDP Sciences, 2017.This work was carried out at the Ural Federal University and Science Foundation (project no. 14-19-00524).financially supported by the Russia

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

The development of a high temperature air heating unit based on the external combustion for integrated gasification combined cycle

The use of heat exchangers in which the working fluid before it enters the gas turbine is warmed up due to the combustion of fuel or other external energy source still is of interest due to the method advantages: the cleanliness of the working fluid; the ability of using cheap low-grade fuels, solar or nuclear energy; the possibility of usage of the closed gas turbine cycle with gases as a working medium, that having favorable thermodynamic properties in comparison with air (helium, CO2, etc.). However, the desired gas turbine inlet temperature - up to 1,700°C currently not possible to provide even with the use of ceramic heat exchangers. Therefore, this technology is now being considered for solid-fuel micro gas turbines operating at temperatures 900-1100°C, or for reducing the need for fuel gas of integrated gasification combined cycle (IGCC) by the means of preheating of cyclic air as well as it is considered for solar gas turbines and gas turbines on the basis of high temperature gas cooled reactors. The authors have developed a metal recuperative air heater based on external combustion of coal for 500 MW IGCC power plant, the development of IGCC is determined by the Energy strategy of Russia for the period up to 2030. In the article the thermal characteristics of the heating of pressurized air, the possible options for the configuration of the heater, heat-resistant materials suitable for its production and the results of the feasibility calculations are considered. In conclusion the design that allows to significantly reduce the specific capital and operating costs for the heater compared to the classic one is proposed. © Published under licence by IOP Publishing Ltd.This work was carried out at the Ural Federal University and financially supported by the Russian Science Foundation (project number 14-19-00524).Comsol;GazEcos;Interenergo;Russian Foundation for Basic Researc

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)

Production of nanoporous sorbents by partial steam-air conversion of charcoal

An effective sorbent is activated carbon having a developed nanoporous structure with an average pore diameter about 2-4 nm. Perspective method of activated carbon production is the partial steam conversion of the coal bed in boiler furnaces of power plants. The additional thermal energy is produced by burning the syngas. The aim of this work is to study the co-production of activated carbon and syngas by partial steam-air conversion of charcoal. Due to the presence of oxygen in the flow, intensification of conversion occurs. In the laboratory bed reactor, the mass loss curves and the syngas composition were obtained at temperatures of 800°C and 900°C. Two zones with different reaction mechanisms were identified on the height of the bed. The reactions between carbon and steam shift toward hydrogen formation in the oxygen zone. The dependence of the porous structure of the activated carbon on the conversion degree of the raw material is obtained. The maximum of micropores is formed at a conversion degree of 0.5. The material and energy balance of the partial conversion in the laboratory reactor was estimated. © 2018 Institute of Physics Publishing. All rights reserved.Russian Foundation for Basic Research (RFBR

Analytical modeling of hot gas clean up reactor

Thermal sustainability of zinc oxide was studied. Experiments were conducted in atmosphere of syngas components. Thermogravimetrical analysis was used as the main method of investigation. Zinc oxide based sorbents were tested in methane, hydrogen, carbon and hydrogen sulphide atmospheres. Experimental data has shown intensification of reactions between zinc oxide and methane, hydrogen and carbon in temperature range from 650 to 800 °C and zinc evaporation and sorbent chemical destruction. Experiments did not reveal significant change of rate constant of reaction between zinc oxide and hydrogen sulphide. Ten probable reactions were numerically analysed. Equilibrium constants were calculated for all ten reactions. The temperature influence on equilibrium constants were calculated. Some elements of hot gas clean up desulfurization unit simulation model were also presented. Experimental rate constants for both four reactions were used in the model. Outlet gas composition and efficiency factor were calculated. Sorbent mass flow was determined. Recommended temperature range was identified. © 2018 Institute of Physics Publishing. All rights reserved.Russian Foundation for Basic Research (RFBR

Technical and economical evaluation of a high-temperature air heater intended for integrated gasification combined cycle unit

In this paper the costs of creating a high-temperature air heater intended for the integrated gasification combined cycle unit developed by the authors are estimated and are compared with a steam boiler. The results can be used not only in the further development of the integrated gasification combined cycle plant under consideration, but also be interesting to specialists involved in the development of various high-temperature heat exchangers. © 2020 Institute of Physics Publishing. All rights reserved.The study was financially supported by the Russian Foundation for Basic Research (No. 14-08-01226)

Selecting the design of a high-temperature air heater for integrated gasification combined cycle

High temperature heat exchangers are needed in various energy technologies to increase their efficiency. The article is devoted to the optimization of the design of a high-temperature air heater used in the integrated gasification combined cycle plant, developed in Ural Federal University. In the air heater, air with a pressure of 2 MPa after the cycle compressor is heated by coal combustion to a temperature of 900°C before it is fed into the combustion chamber of a gas turbine. The air heater is developed as a pulverized coal fired boiler with air heating in tubular radiation-convection heating surfaces. The authors propose a new design of a high-temperature air heater, which allows reducing the cost of the expensive high-temperature part of the unit 1.8 times compared with the previous design. A computer simulation of the boiler section is carried out to verify the proposed design solutions. © Published under licence by IOP Publishing Ltd