Performance improvement of a Circulating Fluidized Bed Boiler through flow modifications in Primary Air Supply System

Xiaozhou Liu, Guangyu Zhu, Yu Zhang, Taimoor Asim, Rakesh Mishra

Research output: Contribution to journalArticle

Abstract

The primary air supply system is a key component of a Circulating Fluidized Bed (CFB) boiler. The uniformity of air flow through the primary air supply system is important for highly efficient operation of the CFB boiler. Non-uniform air flow distribution within the primary air supply system can affect the boiler's combustion adversely, resulting in higher energy consumptions. An effective measure to solve this problem is to install an air flow modifier in the primary air supply system. Thus, extensive numerical investigations have been carried out to design a suitable air flow modifier in order to improve operational efficiency of the CFB boiler. It has been shown that inhomogeneity in the air flow velocity, at a control cross-section of the wind-box, reduces from 65.79% to 21.25% when flow modifier is used. In order to validate the numerical results, visual and velocity distribution uniformity experiments have been conducted under five different test conditions. For this purpose, a small-scale model of a 220t/hr CFB boiler has been used. The experimental results substantiate the numerical predictions. Moreover, the same methodology has been implemented to a full-scale 220t/hr CFB boiler. The hot test results depict that the thermal efficiency of the boiler has increased from 85.71% to 88.34% when tested with an air flow modifier in place, which is equivalent to a saving of 5,000 tons of coal per year. The economic benefits of this energy-saving technology have been shown to be very significant, clearly demonstrating the effectiveness of the air flow modifier.
Original languageEnglish
Pages (from-to)29-43
Number of pages15
JournalInternational Journal of COMADEM
Volume22
Issue number4
Publication statusPublished - 18 Nov 2019

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Fluidized beds
Boilers
Air
Performance improvement
Air flow
Coal
Velocity distribution
Flow velocity
Energy conservation
Energy utilization
Economics

Cite this

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title = "Performance improvement of a Circulating Fluidized Bed Boiler through flow modifications in Primary Air Supply System",
abstract = "The primary air supply system is a key component of a Circulating Fluidized Bed (CFB) boiler. The uniformity of air flow through the primary air supply system is important for highly efficient operation of the CFB boiler. Non-uniform air flow distribution within the primary air supply system can affect the boiler's combustion adversely, resulting in higher energy consumptions. An effective measure to solve this problem is to install an air flow modifier in the primary air supply system. Thus, extensive numerical investigations have been carried out to design a suitable air flow modifier in order to improve operational efficiency of the CFB boiler. It has been shown that inhomogeneity in the air flow velocity, at a control cross-section of the wind-box, reduces from 65.79{\%} to 21.25{\%} when flow modifier is used. In order to validate the numerical results, visual and velocity distribution uniformity experiments have been conducted under five different test conditions. For this purpose, a small-scale model of a 220t/hr CFB boiler has been used. The experimental results substantiate the numerical predictions. Moreover, the same methodology has been implemented to a full-scale 220t/hr CFB boiler. The hot test results depict that the thermal efficiency of the boiler has increased from 85.71{\%} to 88.34{\%} when tested with an air flow modifier in place, which is equivalent to a saving of 5,000 tons of coal per year. The economic benefits of this energy-saving technology have been shown to be very significant, clearly demonstrating the effectiveness of the air flow modifier.",
keywords = "Circulating Fluidized Bed (CFB), Computational Fluid Dynamics (CFD), Cold test, Error analysis, Primary Air Supply System, Air Flow Modifier",
author = "Xiaozhou Liu and Guangyu Zhu and Yu Zhang and Taimoor Asim and Rakesh Mishra",
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Performance improvement of a Circulating Fluidized Bed Boiler through flow modifications in Primary Air Supply System. / Liu, Xiaozhou; Zhu, Guangyu ; Zhang, Yu; Asim, Taimoor; Mishra, Rakesh.

In: International Journal of COMADEM, Vol. 22, No. 4, 18.11.2019, p. 29-43.

Research output: Contribution to journalArticle

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T1 - Performance improvement of a Circulating Fluidized Bed Boiler through flow modifications in Primary Air Supply System

AU - Liu, Xiaozhou

AU - Zhu, Guangyu

AU - Zhang, Yu

AU - Asim, Taimoor

AU - Mishra, Rakesh

PY - 2019/11/18

Y1 - 2019/11/18

N2 - The primary air supply system is a key component of a Circulating Fluidized Bed (CFB) boiler. The uniformity of air flow through the primary air supply system is important for highly efficient operation of the CFB boiler. Non-uniform air flow distribution within the primary air supply system can affect the boiler's combustion adversely, resulting in higher energy consumptions. An effective measure to solve this problem is to install an air flow modifier in the primary air supply system. Thus, extensive numerical investigations have been carried out to design a suitable air flow modifier in order to improve operational efficiency of the CFB boiler. It has been shown that inhomogeneity in the air flow velocity, at a control cross-section of the wind-box, reduces from 65.79% to 21.25% when flow modifier is used. In order to validate the numerical results, visual and velocity distribution uniformity experiments have been conducted under five different test conditions. For this purpose, a small-scale model of a 220t/hr CFB boiler has been used. The experimental results substantiate the numerical predictions. Moreover, the same methodology has been implemented to a full-scale 220t/hr CFB boiler. The hot test results depict that the thermal efficiency of the boiler has increased from 85.71% to 88.34% when tested with an air flow modifier in place, which is equivalent to a saving of 5,000 tons of coal per year. The economic benefits of this energy-saving technology have been shown to be very significant, clearly demonstrating the effectiveness of the air flow modifier.

AB - The primary air supply system is a key component of a Circulating Fluidized Bed (CFB) boiler. The uniformity of air flow through the primary air supply system is important for highly efficient operation of the CFB boiler. Non-uniform air flow distribution within the primary air supply system can affect the boiler's combustion adversely, resulting in higher energy consumptions. An effective measure to solve this problem is to install an air flow modifier in the primary air supply system. Thus, extensive numerical investigations have been carried out to design a suitable air flow modifier in order to improve operational efficiency of the CFB boiler. It has been shown that inhomogeneity in the air flow velocity, at a control cross-section of the wind-box, reduces from 65.79% to 21.25% when flow modifier is used. In order to validate the numerical results, visual and velocity distribution uniformity experiments have been conducted under five different test conditions. For this purpose, a small-scale model of a 220t/hr CFB boiler has been used. The experimental results substantiate the numerical predictions. Moreover, the same methodology has been implemented to a full-scale 220t/hr CFB boiler. The hot test results depict that the thermal efficiency of the boiler has increased from 85.71% to 88.34% when tested with an air flow modifier in place, which is equivalent to a saving of 5,000 tons of coal per year. The economic benefits of this energy-saving technology have been shown to be very significant, clearly demonstrating the effectiveness of the air flow modifier.

KW - Circulating Fluidized Bed (CFB)

KW - Computational Fluid Dynamics (CFD)

KW - Cold test

KW - Error analysis

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KW - Air Flow Modifier

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