Abstract
The important control parameter for the combustion of gaseous fuels is the maintenance of the gas-air ratio, which is provided by taking into account the stoichiometric coefficient of the gaseous fuel. During combustion of the mixed gas, the ratio of components in the gas mixture is not controlled, or the stoichiometric factor is not constant, the maintaining of optimal gas - air ratio is quite difficult. In addition, the combustion of gas is affected by uncontrolled air leaks in the working space where a combustion process takes place. The use of a control search engine makes it possible to determine the optimal gas-air ratio during the continuous search, but the operation of such systems should not affect the safety of the process. The two subsystems, the stabilization subsystem and the search engine, are considered in the paper. Each of the subsystems is a separate control circuit that works sequentially. The switching of operation from one system to another is carried out according to the condition, which is formed using the method proposed in the work. In case of intensive temperature condition changes and corresponding gas flow changes, control should be carried out by using the stabilizing subsystem and, upon reaching the parameters of the controlled process of the predetermined zone, it will be switched to the optimization subsystem, which searches for the most efficient gas-air ratio for the current condition determined by the thermal effect from combustion. The use of the energy-saving mixed gas combustion control system under consideration in a single methodical furnace with the capacity of 110 tonnes/h made it possible to reduce conventional fuel costs by 12.4 tonnes/day.
Keywords
Mixed gas, calorific value, air flow coefficient, fuel combustion, energy saving, dual-loop control, extremum control.
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