The Experts below are selected from a list of 93 Experts worldwide ranked by ideXlab platform

Wenming Yang - One of the best experts on this subject based on the ideXlab platform.

  • Development of a numerical model for co-combustion of the blended solid waste fuel in the grate boiler
    Chemical Engineering Journal, 2020
    Co-Authors: Anqi Zhou, Wenming Yang, Xiaoxiao Meng, Rui Sun
    Abstract:

    Abstract This paper presents a model developed to numerically simulate the combustion of blended solid fuel in the grate boiler. The model can efficiently reproduce the thermal conversion process through a separate definition of the participating fuel by their unique physical and chemical properties. The advantage of this consideration is its flexibility and comprehensiveness in understanding and predicting the system reaction. The model is firstly validated with lab-scale experimental results. The validation shows that after the mechanism kinetics is determined through mono-combustion, the model is able to resemble the co-combustion result through direct numerical blending. This model is then extended for application in the industrial-scale boiler to investigate the blended combustion of waste wood chips with different ash content. The mono-combustion of the fuel is verified against boiler measurements, and then the effect of blending ratio and Air Supply is analyzed numerically. The results show that co-combustion can enhance on-grate carbon conversion as well as overall efficiency, as the low ash fuel content increase. Moreover, increasing the Primary Air Supply while keeping the same total Air excess can also elevate the thermal efficiency effectively.

  • numerical investigation of the effect of Air Supply and oxygen enrichment on the biomass combustion in the grate boiler
    Applied Thermal Engineering, 2019
    Co-Authors: Anqi Zhou, Hongpeng Xu, Yaojie Tu, Feiyang Zhao, Zhiming Zheng, Wenming Yang
    Abstract:

    Abstract The characteristics of biomass combustion in industrial scale grate boiler under different operating conditions are investigated based on the numerical model. On account of the one-dimensional dynamics assumption, a fuel bed model is developed to simulate the biomass incineration on the grate bed, while interacting with three-dimensional CFD furnace model to provide a thoughtful representation of the whole boiler. The model validation is performed based on the experimental data and is used as the standard basis for further investigation. The effect of Air Supply is analyzed with a combination of numerical results and efficiency analysis. Under constant excess Air ratio, the thermal efficiency of the boiler is raised greatly when the Primary Air Supply is elevated to 43% of the total Air Supply, but the improvement is limited when the ratio of Primary Air is further increased to 50%. The influence of redistribution of Primary Air Supply in zone 4 and zone 5 on the thermal efficiency is dependent on the conversion rate of fuel in the first three zones, although the bottom ash temperature can be reduced through increasing the Air flow in zone 5. An increase in excess Air ratio contributes to better burnout but stack loss increase simultaneously, so an optimum ratio is found to be 1.6. Oxygen-enriched combustion is also explored in this study. The combustion improves obviously by enriching the volume fraction of O2 in Primary Air to 25%, and the highest temperature in the grate bed is below 1400 K, which is the limitation from the design specification of this commercial grate boiler.

  • Numerical Study of Biomass Grate Boiler with Coupled Time-Dependent Fuel Bed Model and Computational Fluid Dynamics Based Freeboard Model
    Energy & Fuels, 2018
    Co-Authors: Anqi Zhou, Wenming Yang, Siah Keng Boon, Prabakaran Subbaiah
    Abstract:

    In this paper, a coupled numerical model is developed to provide an advanced simulation for industrial scale grate boilers. The detailed process of biomass conversion in the grate bed is captured using the developed one-dimensional fuel bed model, taking into consideration the separately controlled residence time and Primary Air Supply in different zones. The distributions of gas concentrations, temperature, and bed height along the grate bed are described by the transient simulation results, which are then coupled to the three-dimensional freeboard simulation model as boundary conditions. The results from the coupled model are compared with the on-site measurement data from a wood-chip grate boiler for steam generation, and good agreements are achieved. The in-furnace combustion processes for different quality fuels are evaluated using the model. The results show that higher quality fuel has a larger high temperature combustion zone together with a lower bottom ash temperature, which suggests a higher ef...

Anqi Zhou - One of the best experts on this subject based on the ideXlab platform.

  • Development of a numerical model for co-combustion of the blended solid waste fuel in the grate boiler
    Chemical Engineering Journal, 2020
    Co-Authors: Anqi Zhou, Wenming Yang, Xiaoxiao Meng, Rui Sun
    Abstract:

    Abstract This paper presents a model developed to numerically simulate the combustion of blended solid fuel in the grate boiler. The model can efficiently reproduce the thermal conversion process through a separate definition of the participating fuel by their unique physical and chemical properties. The advantage of this consideration is its flexibility and comprehensiveness in understanding and predicting the system reaction. The model is firstly validated with lab-scale experimental results. The validation shows that after the mechanism kinetics is determined through mono-combustion, the model is able to resemble the co-combustion result through direct numerical blending. This model is then extended for application in the industrial-scale boiler to investigate the blended combustion of waste wood chips with different ash content. The mono-combustion of the fuel is verified against boiler measurements, and then the effect of blending ratio and Air Supply is analyzed numerically. The results show that co-combustion can enhance on-grate carbon conversion as well as overall efficiency, as the low ash fuel content increase. Moreover, increasing the Primary Air Supply while keeping the same total Air excess can also elevate the thermal efficiency effectively.

  • numerical investigation of the effect of Air Supply and oxygen enrichment on the biomass combustion in the grate boiler
    Applied Thermal Engineering, 2019
    Co-Authors: Anqi Zhou, Hongpeng Xu, Yaojie Tu, Feiyang Zhao, Zhiming Zheng, Wenming Yang
    Abstract:

    Abstract The characteristics of biomass combustion in industrial scale grate boiler under different operating conditions are investigated based on the numerical model. On account of the one-dimensional dynamics assumption, a fuel bed model is developed to simulate the biomass incineration on the grate bed, while interacting with three-dimensional CFD furnace model to provide a thoughtful representation of the whole boiler. The model validation is performed based on the experimental data and is used as the standard basis for further investigation. The effect of Air Supply is analyzed with a combination of numerical results and efficiency analysis. Under constant excess Air ratio, the thermal efficiency of the boiler is raised greatly when the Primary Air Supply is elevated to 43% of the total Air Supply, but the improvement is limited when the ratio of Primary Air is further increased to 50%. The influence of redistribution of Primary Air Supply in zone 4 and zone 5 on the thermal efficiency is dependent on the conversion rate of fuel in the first three zones, although the bottom ash temperature can be reduced through increasing the Air flow in zone 5. An increase in excess Air ratio contributes to better burnout but stack loss increase simultaneously, so an optimum ratio is found to be 1.6. Oxygen-enriched combustion is also explored in this study. The combustion improves obviously by enriching the volume fraction of O2 in Primary Air to 25%, and the highest temperature in the grate bed is below 1400 K, which is the limitation from the design specification of this commercial grate boiler.

  • Numerical investigation the effect of Air Supply on the biomass combustion in the grate boiler
    Energy Procedia, 2019
    Co-Authors: Anqi Zhou, Feiyang Zhao, Siah Keng Boon, Yang Wenming, Prabakaran Subbaiah
    Abstract:

    Abstract The burning behavior of biomass in the industrial-scale grate boiler is investigated through numerical simulation. A dynamic one-dimensional model is developed to simulate the biomass combustion in the grate bed. The three-dimension simulation is also employed to determine the radiation temperature as the boundary condition for the developed model. The model is validated with experimental measurements. The effect of Air Supply for biomass combustion characteristics in the grate bed is discussed based on the simulation results. It is found that the increase of Air Supply shortens the burning time and raises the maximum combustion temperature. Under the condition of constant excess Air ratio, the fuel can be burnt out in advance by increasing Primary Air Supply, but the radiation temperature in the zone 1 of grate bed is decreased when the ratio of Primary Air is larger than 43%. Based on these predicted results, the suggested ratio of Primary to secondary Air is 43:57 for this industrial-scale grate boiler. The effect of Primary Air flow distribution in different zones is also investigated to reduce the heat loss from bottom ash.

  • Numerical Study of Biomass Grate Boiler with Coupled Time-Dependent Fuel Bed Model and Computational Fluid Dynamics Based Freeboard Model
    Energy & Fuels, 2018
    Co-Authors: Anqi Zhou, Wenming Yang, Siah Keng Boon, Prabakaran Subbaiah
    Abstract:

    In this paper, a coupled numerical model is developed to provide an advanced simulation for industrial scale grate boilers. The detailed process of biomass conversion in the grate bed is captured using the developed one-dimensional fuel bed model, taking into consideration the separately controlled residence time and Primary Air Supply in different zones. The distributions of gas concentrations, temperature, and bed height along the grate bed are described by the transient simulation results, which are then coupled to the three-dimensional freeboard simulation model as boundary conditions. The results from the coupled model are compared with the on-site measurement data from a wood-chip grate boiler for steam generation, and good agreements are achieved. The in-furnace combustion processes for different quality fuels are evaluated using the model. The results show that higher quality fuel has a larger high temperature combustion zone together with a lower bottom ash temperature, which suggests a higher ef...

Feiyang Zhao - One of the best experts on this subject based on the ideXlab platform.

  • numerical investigation of the effect of Air Supply and oxygen enrichment on the biomass combustion in the grate boiler
    Applied Thermal Engineering, 2019
    Co-Authors: Anqi Zhou, Hongpeng Xu, Yaojie Tu, Feiyang Zhao, Zhiming Zheng, Wenming Yang
    Abstract:

    Abstract The characteristics of biomass combustion in industrial scale grate boiler under different operating conditions are investigated based on the numerical model. On account of the one-dimensional dynamics assumption, a fuel bed model is developed to simulate the biomass incineration on the grate bed, while interacting with three-dimensional CFD furnace model to provide a thoughtful representation of the whole boiler. The model validation is performed based on the experimental data and is used as the standard basis for further investigation. The effect of Air Supply is analyzed with a combination of numerical results and efficiency analysis. Under constant excess Air ratio, the thermal efficiency of the boiler is raised greatly when the Primary Air Supply is elevated to 43% of the total Air Supply, but the improvement is limited when the ratio of Primary Air is further increased to 50%. The influence of redistribution of Primary Air Supply in zone 4 and zone 5 on the thermal efficiency is dependent on the conversion rate of fuel in the first three zones, although the bottom ash temperature can be reduced through increasing the Air flow in zone 5. An increase in excess Air ratio contributes to better burnout but stack loss increase simultaneously, so an optimum ratio is found to be 1.6. Oxygen-enriched combustion is also explored in this study. The combustion improves obviously by enriching the volume fraction of O2 in Primary Air to 25%, and the highest temperature in the grate bed is below 1400 K, which is the limitation from the design specification of this commercial grate boiler.

  • Numerical investigation the effect of Air Supply on the biomass combustion in the grate boiler
    Energy Procedia, 2019
    Co-Authors: Anqi Zhou, Feiyang Zhao, Siah Keng Boon, Yang Wenming, Prabakaran Subbaiah
    Abstract:

    Abstract The burning behavior of biomass in the industrial-scale grate boiler is investigated through numerical simulation. A dynamic one-dimensional model is developed to simulate the biomass combustion in the grate bed. The three-dimension simulation is also employed to determine the radiation temperature as the boundary condition for the developed model. The model is validated with experimental measurements. The effect of Air Supply for biomass combustion characteristics in the grate bed is discussed based on the simulation results. It is found that the increase of Air Supply shortens the burning time and raises the maximum combustion temperature. Under the condition of constant excess Air ratio, the fuel can be burnt out in advance by increasing Primary Air Supply, but the radiation temperature in the zone 1 of grate bed is decreased when the ratio of Primary Air is larger than 43%. Based on these predicted results, the suggested ratio of Primary to secondary Air is 43:57 for this industrial-scale grate boiler. The effect of Primary Air flow distribution in different zones is also investigated to reduce the heat loss from bottom ash.

Zhiming Zheng - One of the best experts on this subject based on the ideXlab platform.

  • numerical investigation of the effect of Air Supply and oxygen enrichment on the biomass combustion in the grate boiler
    Applied Thermal Engineering, 2019
    Co-Authors: Anqi Zhou, Hongpeng Xu, Yaojie Tu, Feiyang Zhao, Zhiming Zheng, Wenming Yang
    Abstract:

    Abstract The characteristics of biomass combustion in industrial scale grate boiler under different operating conditions are investigated based on the numerical model. On account of the one-dimensional dynamics assumption, a fuel bed model is developed to simulate the biomass incineration on the grate bed, while interacting with three-dimensional CFD furnace model to provide a thoughtful representation of the whole boiler. The model validation is performed based on the experimental data and is used as the standard basis for further investigation. The effect of Air Supply is analyzed with a combination of numerical results and efficiency analysis. Under constant excess Air ratio, the thermal efficiency of the boiler is raised greatly when the Primary Air Supply is elevated to 43% of the total Air Supply, but the improvement is limited when the ratio of Primary Air is further increased to 50%. The influence of redistribution of Primary Air Supply in zone 4 and zone 5 on the thermal efficiency is dependent on the conversion rate of fuel in the first three zones, although the bottom ash temperature can be reduced through increasing the Air flow in zone 5. An increase in excess Air ratio contributes to better burnout but stack loss increase simultaneously, so an optimum ratio is found to be 1.6. Oxygen-enriched combustion is also explored in this study. The combustion improves obviously by enriching the volume fraction of O2 in Primary Air to 25%, and the highest temperature in the grate bed is below 1400 K, which is the limitation from the design specification of this commercial grate boiler.

Yaojie Tu - One of the best experts on this subject based on the ideXlab platform.

  • numerical investigation of the effect of Air Supply and oxygen enrichment on the biomass combustion in the grate boiler
    Applied Thermal Engineering, 2019
    Co-Authors: Anqi Zhou, Hongpeng Xu, Yaojie Tu, Feiyang Zhao, Zhiming Zheng, Wenming Yang
    Abstract:

    Abstract The characteristics of biomass combustion in industrial scale grate boiler under different operating conditions are investigated based on the numerical model. On account of the one-dimensional dynamics assumption, a fuel bed model is developed to simulate the biomass incineration on the grate bed, while interacting with three-dimensional CFD furnace model to provide a thoughtful representation of the whole boiler. The model validation is performed based on the experimental data and is used as the standard basis for further investigation. The effect of Air Supply is analyzed with a combination of numerical results and efficiency analysis. Under constant excess Air ratio, the thermal efficiency of the boiler is raised greatly when the Primary Air Supply is elevated to 43% of the total Air Supply, but the improvement is limited when the ratio of Primary Air is further increased to 50%. The influence of redistribution of Primary Air Supply in zone 4 and zone 5 on the thermal efficiency is dependent on the conversion rate of fuel in the first three zones, although the bottom ash temperature can be reduced through increasing the Air flow in zone 5. An increase in excess Air ratio contributes to better burnout but stack loss increase simultaneously, so an optimum ratio is found to be 1.6. Oxygen-enriched combustion is also explored in this study. The combustion improves obviously by enriching the volume fraction of O2 in Primary Air to 25%, and the highest temperature in the grate bed is below 1400 K, which is the limitation from the design specification of this commercial grate boiler.