A heating and supplementary combustion system for power plant boilers under low-load operation

Abstract

The invention discloses a temperature rising afterburning system for utility boiler operating at a low load. The temperature rising afterburning system comprises a high temperature superheater, a high temperature reheater and an afterburner, wherein the afterburner comprises an afterburning nozzle, a thermal decomposition chamber, a smoke pipeline, a pulverized coal feed pipeline, a circulating pipeline and a shade gas-solid separator; the thermal decomposition chamber is communicated with the smoke pipeline, the pulverized coal feed pipeline and the circulating pipeline respectively; the shade gas-solid separator is mounted in a pipeline at the upper part of the circulating pipeline and connected with the circulating pipeline and the afterburning nozzle respectively; the afterburning nozzle is connected onto the top end of the shade gas-solid separator and mounted between the high temperature superheater and the high temperature reheater both in a horizontal flue of the boiler in an inserting manner; pulverized coal brought into by primary air of a powder feeding system and smoke from the hearth of the boiler pass through the pulverized coal feed pipeline and the smoke pipeline respectively and then are mixed in the thermal decomposition chamber, solid-gas separation is performed on the mixed product in the shade gas-solid separator, and the gas is delivered to the afterburning nozzle for burning support. The temperature rising afterburning system for the utility boiler operating at low load is simple in structure, stable in operation, excellent in safety and high in operating efficiency.

Description

technical field [0001] The invention relates to equipment in a power generation system of a thermal power plant, in particular to a heating supplementary combustion system under low-load operation of a power plant boiler. Background technique [0002] In order to improve thermal economy, modern large-scale thermal power units often use intermediate reheating systems. These units have become the absolute main force in my country's major power grids. However, according to statistics, a large part of the boiler reheater temperature adjustment devices cannot be used normally, which means that the reheat steam temperature of a large number of boilers cannot reach the design value, and the coal consumption of some units has increased by 2-5 grams / KWh . [0003] The reheat steam temperature is affected by various operating factors of the boiler, such as changes in boiler load, feed water temperature, fuel properties, combustion conditions, and cleanliness of the heating surface. ...

AI Technical Summary

Problems solved by technology

However, according to statistics, a large part of the boiler reheater temperature adjustment devices cannot be used normally, which means that the reheat steam temperature of a large number of boilers cannot reach the design value, and the coal consumption of some units has increased by 2-5 grams / KWh

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