Device and method for waste heat recovery based on control over outlet smoke temperature

Abstract

The invention relates to a device for waste heat recovery based on control over outlet smoke temperature. According to the device, a smoke adjusting baffle and a bypass flue are arranged in an original flue and a temperature sensor is arranged in the flue; the bypass flue is communicated with a smoke heat exchanger and the smoke heat exchanger is connected with a steam pocket; the steam pocket is communicated with an air heat exchanger in an air side flue through a saturated steam output pipe and the air heat exchanger is further communicated with the steam pocket through a condensate water input pipeline so that circulation can be formed; a condensate water circulation pump is arranged on the condensate water input pipeline; a liquid level sensor is arranged on the air heat exchanger; the steam pocket is provided with a steam pocket pressure sensor. The outlet smoke temperature is controlled by the adjusting baffle, smoke is shunted by the adjusting baffle, and therefore it is guaranteed that the temperature of the discharged smoke is stabilized at a set value; according to control over the steam pressure of the steam pocket, the backflow speed of condensate water is controlled to control the heat exchange area of a heat exchange system, and therefore control over the heat exchange power of the heat exchangers is achieved.

Description

technical field [0001] The invention relates to a waste heat recovery device and method, in particular to a waste heat recovery device and a waste heat recovery method based on outlet smoke temperature control. Background technique [0002] As an important and feasible waste treatment method, waste incineration power generation has broad market development prospects. Compared with the coal burning process of power stations, the waste incineration process has the characteristics of high fly ash content and low ash melting point. Therefore, in the combustion process Problems such as dust accumulation and slagging on the heat transfer surface are prone to occur. With the passage of operation time, the increase of dust accumulation in the flue will gradually reduce the heat transfer coefficient of the boiler, increase the thermal resistance, and increase the exhaust gas temperature. For example, due to the serious ash accumulation problem in a waste incineration power plant, the...

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Problems solved by technology

[0007] It can be seen that the control system using only one heat exchanger can no longer meet the control requirements of the above parameters. To maintain a relatively stable flue gas outlet temperature under different loads and flue temperature inlets, it is necessary to control the temperature of the flue gas at the outlet of the heat exchanger. The temperature controls the opening of the flue gas baffle, and then controls the heat transfer power on the flue gas side. At the same time, on the air side, the heat transfer power of the heat exchanger also needs to be controlled. The control strategy needs to ensure the matching of the heat absorption and release energy of the system.

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