Method for improving thermodynamic cycling quality of waste sinter heat power generation system

Abstract

The invention relates to the technical field of waste heat power generation, in particular to a method for improving the thermodynamic cycling quality of a waste sinter heat power generation system. The method comprises the following steps of: coupling the thermodynamic cycle of waste sinter heat power generation with the thermodynamic cycle of conventional blast furnace gas power generation, using a waste heat boiler as an external economizer of a blast furnace gas boiler; mixing saturated water generated by the waste heat boiler with hot water generated by an internal economizer of the blast furnace gas boiler and directly delivering the mixed water to a steam manifold of the blast furnace gas boiler; performing evaporation and superheating on the mixed water in the blast furnace gas boiler and allowing the mixed water to enter a steam turbine to apply work; and dividing the discharged smoke of the waste heat boiler into two parts, wherein one part is recycled as waste gas and is returned to a fan of a sinter cooler, while the other part enters the blast furnace gas boiler to support the combustion of fuels. The method utilizes the thermodynamic cycle of thermal power generation to develop the thermodynamic cycle of the waste heat power generation, solves the problems of poor stability and low thermo-electric conversion efficiency in the prior low-temperature waste sinter heat power generation system, and greatly improves the thermodynamic cycling quality of the waste heat power generation.

Description

Technical field: [0001] The invention relates to a method for improving the thermal cycle quality of a sintering waste heat power generation system, in particular to a method for improving the thermal cycle quality of a sintering waste heat power generation system by coupling the sintering waste heat power generation system with a conventional blast furnace gas power generation system. Background technique: [0002] At present, the known sintering waste heat power generation systems all adopt the thermodynamic cycle mode of pure low-temperature waste heat power generation. The pure low-temperature waste heat power generation system uses sintering waste gas as a single heat source to heat water into steam to drive the steam turbine to do work. Due to the characteristics of low temperature and large fluctuation of sintering waste heat, compared with the thermal cycle of conventional thermal power generation system, the quality of thermal cycle of sintering pure low-temperature ...

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Problems solved by technology

[0007](2) The main steam pressure is low

[0011] According to the basic principles of engineering thermodynamics, the level of steam parameters is the main factor determining the efficiency of thermal cycle. Since the main and auxiliary steam parameters of sintered pure low-temperature waste heat power generation system are very low, the basic Rankine cycle efficiency of its thermal cycle is only 25%-30 %, because the reduction of steam parameters can simultaneously lead to an increase in the irreversible loss rate of steam in the process of steam work in the steam turbine, the actual cycle efficiency of sintering pure low-temperature waste heat power generation thermodynamic cycle is only 20%-25%, which is 15% lower than the actual cycle efficiency of thermal power generation system %about

[0012] (2) The utilization rate of sintering waste heat is low for sintering pure low-temperature waste heat power generation thermodynamic cycle

[0013] In the known sintering waste heat power generation system, the temperature of the exhaust gas entering the waste heat boiler is generally 310°C-350°C (considering the heat dissipation of the flue), and the exhaust gas temperature of the waste heat boiler is generally about 160°C. Enter the thermodynamic cycle, so the utilization rate of the thermal cycle for sintering waste heat is only 45-60%

[0014] (3) The thermodynamic cycle stability of sintered pure low-temperature waste heat power generation is poor

As we all know, the design of the sintering waste heat power generation system is designed according to the average parameters of the exhaust gas. When the fluctuation range of the exhaust gas parameters exceeds a certain value, the fluctuation range of the main steam parameters of the waste heat boiler will exceed the allowable value of the steam turbine, which will affect the safety of the generator set, resulting in Abnormal shutdown, when the fluctuation of auxiliary steam parameters exceeds a certain value, it will affect the normal steam intake of the steam turbine, and in severe cases, the steam intake system will fail

The operation practice of the sintering waste heat power generation system shows that the shutdown rate of the sintering pure low temperature waste heat power generation system, especially the high failure rate of the supplementary steam system is the main problem facing the current sintering pure low temperature waste heat power generation technology

[0016]According to the above discussion, the actual cycle efficiency of sintering low-temperature waste heat power generation system is about 20%-25%, and the utilization rate of sintering waste heat is about 45-60%. It can be seen that the theoretical comprehensive thermoelectric conversion efficiency of the sintering waste heat power generation system is generally not more than 18%. Considering the shutdown rate of the sintering waste heat power generation system in actual operation and the high failure rate of the supplementary steam system, the actual comprehensive thermoelectricity efficiency of the sintering pure low-temperature waste heat power generation system is The conversion efficiency will also decrease. Therefore, the known thermal cycle quality of the sintering waste heat power generation system is poor. To improve the economy of the sintering waste heat power generation system, the quality of the thermal cycle must be improved

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