Optimization of Fluidization State of a Circulating Fluidized Bed Boiler for Economical Operation

Xuemin Liu,Junfu Lyu,Hairui Yang

doi:10.3390/en13020376

Xuemin Liu, Junfu Lyu + Show 1 more

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https://doi.org/10.3390/en13020376

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Abstract

To reduce the auxiliary power consumption and improve the reliability of large-scale circulating fluidized bed (CFB) boilers, we developed energy-saving CFB combustion technology based on the fluidization state re-specification. A calculation model of coal comminution energy consumption was used to analyze the change in comminution energy consumption, and a 1D CFB combustion model was modified to predict the operation parameters under the fluidization state optimization conditions. With a CFB boiler of 480 t/h, the effect of fluidization state optimization on the economical operation was analyzed using the above two models. We found that combustion efficiency presents a nonmonotonic trend with the change in the bed pressure drop and feeding coal size. There are an optimal bed pressure drop and a corresponding feeding coal size distribution, under which the net coal consumption is the lowest. Low bed pressure drop operation achieved by reducing the coal particle size is not beneficial to SO2 and NOx emission control, and the pollutant control cost increases. The effect of fluidization state optimization on the gross cost of power supply can be calculated, and the optimal bed pressure drop can be obtained.

Highlights

Introductioncirculating fluidized bed (CFB) boilers have shown deficiencies, such as high auxiliary power consumption and wear-related problems
With the advantages of fuel flexibility, a wide range of load adjustment and low cost for emission control, the circulating fluidized bed (CFB) boiler has been widely commercialized in recent years.CFB boilers have shown deficiencies, such as high auxiliary power consumption and wear-related problems
Fluidization state re-specification in CFB boilers was proposed, namely flow pattern reconstruction [1,2]. It means that CFB boilers can be operated under a relatively low bed pressure drop by reducing the quantity of ineffective bed materials [3]

Summary

Introduction

CFB boilers have shown deficiencies, such as high auxiliary power consumption and wear-related problems. To solve these problems, fluidization state re-specification in CFB boilers was proposed, namely flow pattern reconstruction [1,2]. Fluidization state re-specification in CFB boilers was proposed, namely flow pattern reconstruction [1,2] It means that CFB boilers can be operated under a relatively low bed pressure drop by reducing the quantity of ineffective bed materials [3]. The aim of this work is to analyze the optimization of fluidization state for the economical operation of CFB boilers

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Conclusion