Modeling study on the dynamic characteristics in the full-loop of a 350 MW supercritical CFB boiler under load regulation

Deng, Boyu; Zhang, Man; Shan, Lu; Wei, Guohua; Lyu, Junfu; Yang, Hairui; Gao, Mingming

doi:10.1016/j.joei.2021.04.014

Cited by 24 publications

(6 citation statements)

References 44 publications

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“…For example, in a downer reactor, the solid circulation flow rate affects the heat transfer and reaction rate, while in a circulating fluidized bed boiler, it affects the boiler load. The ability to adjust and control the solid circulation flow rate reflects the operational flexibility of the device to a certain extent 16 . Therefore, it is very important for the precise control and structural development of the downer to study the variation law and related influencing factors of solid circulation flow rate.…”

Section: Resultsmentioning

confidence: 99%

“…The ability to adjust and control the solid circulation flow rate reflects the operational flexibility of the device to a certain extent. 16 Therefore, it is very important for the precise control and structural development of the downer to study the variation law and related influencing factors of solid circulation flow rate.…”

Section: Factors Affecting Solid Circulation Flow Ratementioning

confidence: 99%

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Experimental study on gas–solid flow and heat transfer characteristics in downer moving bed

Zhang

Zhou

et al. 2023

Asia-Pacific J Chem Eng

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As a special flow state of the downer, the downer moving bed has been applied in many fields. With the rapid development of the downer moving bed, experimental studies on the flow and heat transfer characteristics in the bed are urgently needed to promote the further development of it. Therefore, a complete set of downer moving bed experimental equipment is completed in this paper. Key parameters of flow characteristics such as void fraction and particle flow velocity are indirectly calculated through direct measurement of pressure and other data. The experimental results show that the factors affecting the solid circulation flow rate include bed inventory and inlet air velocity. Due to the high packing density of the particles, the void fraction of the downer moving bed has a small relative change. The particle flow velocity increases significantly with the increase of the inlet air velocity. Under the joint effect of particle velocity and void fraction, the variation of heat transfer coefficient along the height of the bed presents a single peak curve. And the heat transfer performance of the downer moving bed is obviously better than that of the downer fluidized bed at the same solid circulating flow rate. The differences between different tube bank arrangements and the single tube are compared. It is concluded that in practical applications, the requirements for heat transfer and heat transfer coefficient should be considered together and the best tube bank arrangement should be selected.

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Section: Resultsmentioning

confidence: 99%

Section: Factors Affecting Solid Circulation Flow Ratementioning

confidence: 99%

Experimental study on gas–solid flow and heat transfer characteristics in downer moving bed

Zhang

Zhou

et al. 2023

Asia-Pacific J Chem Eng

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“…However, this assumption limits the accuracy of this method. The main reason causing the deviation is that the flow state of the top gas-solid flow in the riser is complicated, and for CFB boilers, it is a fast bed flow state [21]. Therefore, for the fast bed flow state, solid velocity cannot be calculated by Equation ( 5).…”

Section: Correlations Based On Pressure Drop Of Risermentioning

confidence: 99%

Measuring Technologies for CFB Solid Circulation Rate: A Review and Future Perspectives

Liu

Zhang

et al. 2022

Energies

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Solid circulation rate (Gs) represents the mass flux of circulating particles in circulating fluidized bed (CFB) systems and is a significant parameter for the design and operation of CFB reactors. Many measuring technologies for Gs have been proposed, though few of them can be applied in industrial units. This paper presents a comprehensive study on measuring technologies, and the results indicate that though the accumulation method is most widely applied, it is constrained by the disturbance of normal particle circulation. Some publications have proposed mathematic models based on pressure drop or other parameters to establish Gs measurement models; these necessitate the accurate modeling of complicated gas-solid flows in industrial devices. Methods based on certain measurement devices to specify parameters like velocity require device endurance in the industrial operation environment and stable local gas-solid flow. The Gs measuring technologies are strongly influenced by local gas-solid flow states, and the packed bed flow in standpipes make the bottom of standpipes an ideal place to realize Gs measurement.

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“…With the increase of load, the heat transfer coefficient of the distributed parameter model is adjusted to provide reference for heat transfer of supercritical system. Deng et al [8] established a one-dimensional dynamic model of gas-solid flow in the whole loop of industrial CFB on the basis of the mass and pressure balance of the whole loop in order to improve the load regulation capacity of CFB. The model is verified by the data of the solid mass flow rate at the dust outlet of a 350-MW supercritical CFB boiler and the inventory of the cyclone separator during the load increasing process.…”

Section: Introductionmentioning

confidence: 99%

Power supply circuit model and sliding mode control of supercritical unit boiler system commissioning

Lin

Wei

2023

The Journal of Engineering

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In the process of power control and commissioning of supercritical unit boiler system, there are some problems such as large steady-state error and slow response speed. In order to optimize the control performance of supercritical unit boiler system, the power supply loop model and sliding mode control method of supercritical unit boiler system debugging power supply are proposed. Firstly, the power supply circuit model is established according to the data of voltage doubling rectifier circuit, inverter circuit, high frequency transformer and LC resonant circuit. Secondly, the capacitance voltage value and the inductance current value are calculated in the power supply circuit model. Finally, based on the numerical results, a terminal sliding mode controller and a linear sliding mode controller are established to complete the double closed-loop terminal sliding mode control and realize the power control of the debugging power supply. The experimental results show that when the input voltage is 50 V and the current is 14 V, the input voltage and current waveforms remain stable. When the input voltage is between 40 and 50 V, the change of switching frequency is small, only increasing from 22 to 26 kHz. The steady state of the power supply is high, and when the input voltage increases, the DC offset is 21.2. The convergence time in the calculation process is less than 200 ms. The instantaneous change of inductance is 0.7 A. The steady-state error is less than 0.005 V. The output voltage distortion rate is less than 4%. It is proved that this method has strong control performance in the supercritical unit boiler system.

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Modeling study on the dynamic characteristics in the full-loop of a 350 MW supercritical CFB boiler under load regulation

Cited by 24 publications

References 44 publications

Experimental study on gas–solid flow and heat transfer characteristics in downer moving bed

Experimental study on gas–solid flow and heat transfer characteristics in downer moving bed

Measuring Technologies for CFB Solid Circulation Rate: A Review and Future Perspectives

Power supply circuit model and sliding mode control of supercritical unit boiler system commissioning

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