Development of the Method for Predicting and Calculating the Operation of Sorption Systems for Cleaning the Generator Gas based on Dolomite Use. Part II

At present, instead of a direct combustion of solid fuel, its thermochemical conversion is exten-sively used to produce a generator gas. The use of this technology is connected with the need for gas purification. One of the promising and widely spread sorbents for the purification of the generator gas is dolomite, whose particles compose the active component of the bed filters. Forecasting the technological characteristics of the functioning of the bed filters of a various de-sign is an extremely urgent task. The objective of the study is to develop a method for forecast-ing and calculating the operation of sorption systems for purification of the generator gas based on dolomite. It is achieved by constructing and verifying a mathematical model of the function-ing of the bed sorption filter with a radial-axial flow pattern of the generator gas through the do-lomite filling. The Markov chains theory of a mathematical apparatus is used to design the one-dimensional mathematical model of the process with discrete space and time. The main recurrent balance ratio is formed at each calculation step taking into account the current characteristics of the process, which makes the model nonlinear. The significance of the research is that an approach to the problem of increasing the reliability of the description and reliability of forecasting technological processes in a bed filter was proposed based on the construction of mathematical models of these processes, in which the filter is considered as a system with distributed characteristics, and the calculation was based on local exchange potentials between particles and gas.

Development of the Method for Forecasting and Calculating the Operation of Sorption Systems for Purifying the Generator Gas Based on Dolomite Use. Part I

A trend towards energy diversification creates the expansion of small energy facilities that involve the production of solid fuel generator gas, rather than its direct combustion. The economic indicators of such facilities significantly depend on the efficiency of the generator gas purification. A promising sorbent for the purification of the generator gas is dolomite. When working as a sorbent, dolomite particles usually form a layer, through which the generator gas that is heating them is filtered. The objective of the study is to determine kinetic parameters of the thermal decomposition of dolomite, depending on the size of the sample. It was achieved using the thermogravimetric study of the thermal decomposition of single dolomite particles under static conditions at various temperatures. The most significant scientific result was that a dependence of the kinetic parameters of the gross reaction on the size of the initial particle is revealed, and a regression equation was proposed for its quantitative assessment. In addition, since the heat treatment process of the material was fairly long lasting, and the sizes of the particles allowed them to be referred to thermally thin bodies, it was inferred that the effect of a grain size on the reaction kinetics should be explained through the description of the evacuation process of gaseous reaction products from the material. The significance of the results of the study lies in the fact that a particle size must be considered as a factor that affects the progress of the technological process, which increases the reliability of the calculation of sorption-catalytic systems based on the use of dolomite.

Gas flow control in rocket engines

In the new conditions of application of launch vehicle boosters, space tugs, etc., modern rocket engines often do not satisfy the current stringent requirements. This calls for fundamental research into processes in rocket engines for improving their efficiency. In this regard, for the past 5 years, the Department of Thermogas Dynamics of Power Plants of the Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine has conducted research on gas flow control in rocket engines to improve their efficiency and functionality. Mechanisms of flow perturbation in the nozzle of a rocket engine by liquid injection and a solid obstacle were investigated. A mathematical model of supersonic flow perturbation by local liquid injection was refined, and new solutions for increasing the energy release rate of the liquid were developed. A numerical simulation of a gas flow perturbed by a solid obstacle in the nozzle of a rocket engine made it possible to verify the known (mostly experimental) results and to reveal new perturbation features. In particular, a significant increase in the efficiency of flow perturbation by an obstacle in the transonic region was shown up, and some dependences involving the distribution of the perturbed pressure on the nozzle wall, which had been considered universal, were refined. The possibility of increasing the efficiency of use of the generator gas picked downstream of the turbine of a liquid-propellant rocket engine was investigated, and the advantages of a new scheme of gas injection into the supersonic part of the nozzle, which provides both nozzle wall cooling by the generator gas and the production of lateral control forces, were substantiated. A new concept of rocket engine thrust vector control was developed: a combination of a mechanical and a gas-dynamic system. It was shown that such a thrust vector control system allows one to increase the efficiency and reliability of the space rocket stage flight control system. A new liquid-propellant rocket engine scheme was developed to control both the thrust amount and the thrust vector direction in all planes of rocket stage flight stabilization. New approaches to the process organization in auxiliary elements of rocket engines on the basis of detonation propellant combustion were developed to increase the rocket engine performance.

Improvement of Gas Generator Technology for Energy Processing of Agricultural Waste

The article discusses the issues of increasing the energy efficiency of processing agricultural waste in a gas generator. The main goal of this technological process is the production of gas fuel from agricultural waste. This fuel is generator gas. The energy value or calorific value of the generator gas depends on the elementary composition of the solid fuel being processed (straw, animal droppings, peat, wood, carbon-containing industrial waste, etc.) and also on the conditions under which chemical reactions take place in the gas generator. In order to improve the gas generator technology, some innovative technical solutions have been proposed. The solutions are related to controlling the supply of the oxidizer (atmospheric air) to the reaction zone of the gas generator, to recuperate the thermal energy of the gas generator and the combined combustion engine of the power plant for the needs of the gasification process. The solutions are also related to the use of compensation and accumulation systems for supplying the consumer with generator gas and to the spatial positioning of the gas generator housing. The control mode of the oxidizer supply to the reaction zone of the gas generator was also investigated. The analysis of the experimental material allows us to draw a conclusion about the positive effect of control modes on the energy value of the generator gas at non-nominal consumption of generator gas by the consumer. This is a consequence of the optimization of the flow speed of the oxidant from the blowing nozzles of the gas generator. According to the tests of the chemical composition of generator gas in gas generator, depending on the number of electromagnetic valves operating, the largest CO content (approx. 17%) was with five valves, CO2 (approx. 5%) with the lower number of valves, and the O2 was with the highest number of valves. The pressure gauge (discharge in gas generator) was the biggest, according to the lower number of valves. The biggest gas consumption was approx. 6 m3/h.

The Effect of Generator Gas Purity on Heat Rate

This document is designed to explain all aspects of losses associated with operation of a Hydrogen cooled generator when less than pure (100%) Hydrogen is the cooling gas. It will also give a formula which allows the user to calculate the financial impact for the utility when operating at lower purities.

ENERGY EFFICIENCY OF BIOMASS GAS GENERATOR STOVES WITH PERIPHERICAL AND CENTRAL GASES BURNING

This paper is devoted to research and improvement of biomass gas generator stoves. Experience in outdoors application of the gas generator stoves showed a need to stabilize the burning of the generator gas. In previous works, investigations in operation of the gas generator stoves were carried out analogically to that of gas-fired household stoves in the mode of water heating in pot. Stoves operation in the mode of food cooking, which characterized byy other conditions of heat exchange, was not examined. The purpose of work is to investigate the influence of the organization of generator gas and air reaction with protection against atmospheric impacts on the energy efficiency of the gas generator stove in modes, which consistent with the stove usage for water heating for household needs and food boiling. To stabilize the gas generator stove operation, it was proposed to perform the mixing of generator gas with air and their reaction in the combustion chamber with the release of combustion products through the narrowed central opening. Comparison of two stove modifications was made — the first without combustion chamber, named as stove with peripheral burning, in which burning of combustible gas occurs near the air nozzles evenly spaced on the top of reactor; the second stove modification — with a combustion chamber, named as a stove with central burning, in which the combustible gas is more uniformly blended with the air, and burning occurs at center of the combustion chamber. Such an approach protects the combustion zone from atmospheric influences. The methodology of the research consisted in determining the energy efficiency coefficient of the gas generator stove with wood pellets burning at different approaches to the organization of generator gas and air mixing and reacting, as well as clarification of influence of stove application for water heating and water heating with prolonged boiling on stove’s energy efficiency. Experimentally find out, what stove with combustion chamber having central combustion and protection of flame from atmospheric influences in water heating mode had increased efficiency up to 29.6 % compared to 25.1 % for the stove with peripheral burning. The average useful heat productivity of stoves both with the peripheral and central combustion was near the same 1.2 kW. Application of gas generator stove for water heating with its prolonged boiling (cooking mode) led to a decrease in efficiency, for the stove with central burning efficiency decreased from 29.6 % to 21.9 %. Ref. 9, Fig. 1, Tab. 3.