Circulating fluidized bed combustion method for adjusting superheated steam temperature

Abstract

A circulating fluidized bed combustion method for enhancing heat exchange of a hearth heated surface is provided; a circulating fluidized bed includes a circulating fluidized bed hearth, a gas-solid separator and a return feeder which are connected successively and form a circulation loop, and the circulating fluidized bed comprises a tail flue communicating with a gas outlet of the gas-solid separator; the tail flue is internally provided with a tail heated surface. The method comprises the steps: (1) adding a fuel and combustion wind to the hearth, making only 80-95% of the flue combusted in the circulation loop, so as to increase the hearth particle concentration, and controlling the hearth combustion temperature to be 950-1100 DEG C; and (2) introducing additional combustion wind to the tail flue from the upstream of the tail heated surface, making the excess air coefficient of the tail flue to be in a range of 1.05-1.30, and allowing incompletely-combusted combustible components to be completely combusted. The invention also relates to a circulating fluidized bed combustion device for enhancing heat exchange of the hearth heated surface.

Description

technical field [0001] The embodiments of the present invention relate to a circulating fluidized bed combustion method, especially a method for regulating the temperature of superheated steam of a circulating fluidized bed boiler. Background technique [0002] During boiler operation, due to changes in fuel characteristics, feed water temperature, boiler load, etc., changes in superheated steam temperature are inevitable. In order to ensure the safety and economy of the boiler itself and related equipment, it must be adjusted to obtain a stable steam temperature. [0003] The method of adjusting the temperature of superheated steam used on the boiler can be divided into steam side adjustment and flue gas side adjustment. [0004] Steam side adjustment mainly includes water spray cooling and surface cooling. Water spray desuperheating is to spray desuperheating water directly into steam to reduce the temperature of superheated steam. This kind of desuperheater has simple s...

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Problems solved by technology

The flue gas baffle adjustment is to divide the tail flue into two parts, and use the opening of the baffle to change the flue gas flow in the flue, thereby changing the heat absorption of the superheater; but the baffle is large and heavy, and the baffle The opening does not have a linear relationship with the change of steam temperature, the effective opening range is narrow, and it is easy to burn out when working in an area with high smoke temperature

Flue gas recirculation is to send low-temperature flue gas into the furnace through the recirculation fan, and change the heat absorption ratio of the boiler radiation and convection heating surfaces to adjust the steam temperature; Increased losses, affecting boiler efficiency

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