System for high-grade recycling waste heat of smoke discharged from boiler of power station

Abstract

The invention discloses a system for high-grade recycling waste heat of smoke discharged from a boiler of a power station, belonging to the technical field of energy saving. A secondary heat exchanger for smoke waste heat recovery and a primary heat exchanger for smoke waste heat recovery are installed on a flue is sequence along the moving direction of smoke, a primary heat exchanger for air preheating is installed on a connecting duct between an air blower and an air preheater, and the primary heat exchanger for air preheating, the primary heat exchanger for smoke waste heat recovery and a primary circulating water pump form a closed water circulation loop. In the system, the smoke temperature at an outlet of the air preheater is increased by increasing the air temperature at an inlet of the air preheater, and higher smoke waster heat recovery temperature can be obtained; the waste heat can be used for heating feed water, and the high-grade recycling of the smoke waste heat can be realized.

Description

(1) Technical field [0001] The invention belongs to the technical field of energy saving, and in particular relates to a high-grade waste heat recycling system of a power plant boiler. (2) Background technology [0002] The optimum flue gas temperature in the desulfurization process of power plant boilers is 80-90°C, but due to various reasons, the exhaust gas temperature of power plant boilers is currently at 120-150°C, which cannot be further reduced. Therefore, in order to obtain better desulfurization As a result, the temperature of the flue gas must be lowered before entering the desulfurization system. In this way, there is a large amount of high-grade energy loss, and it also increases the power consumption of the plant. [0003] Regarding how to recover the heat energy contained in the flue gas, there are currently mature flue gas waste heat recovery heat exchangers, but they are not satisfactory in terms of utilizing the waste heat of the flue gas. Many patents hav...

AI Technical Summary

Problems solved by technology

[0004] Since the working ability of the low-pressure heater’s extraction is already very low, after the waste heat of the flue gas enters the thermal system of the steam turbine by replacing part of the low-pressure heater’s extraction to heat the condensed water, most of the energy will be lost to the environment in the form of cold abyss loss. Comprehensive utilization efficiency is low

For external heat supply, limited by heat load and heat supply parameters, it is difficult to find suitable heat users and the heat load is stable and continuous all year round

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