The Experts below are selected from a list of 186 Experts worldwide ranked by ideXlab platform

Jose Luz Silveira - One of the best experts on this subject based on the ideXlab platform.

  • thermochemical equilibrium modeling of a biomass Downdraft gasifier constrained and unconstrained non stoichiometric models
    Energy, 2014
    Co-Authors: Andres Z Mendiburu, J A Carvalho, Rolando Zanzi, Christian J R Coronado, Jose Luz Silveira
    Abstract:

    The objective of this work is to develop a non-stoichiometric equilibrium model to study parameter effects in the gasification process of a feedstock in Downdraft Gasifiers. The non-stoichiometric equilibrium model is also known as the Gibbs free energy minimization method. Four models were developed and tested. First a pure non-stoichiometric equilibrium model called M1 was developed; then the methane content was constrained by correlating experimental data and generating the model M2. A kinetic constraint that determines the apparent gasification rate was considered for model M3 and finally the two aforementioned constraints were implemented together in model M4. Models M2 and M4 showed to be the more accurate among the four developed models with mean RMS (root mean square error) values of 1.25 each.

  • thermodynamic analysis and comparison of Downdraft Gasifiers integrated with gas turbine spark and compression ignition engines for distributed power generation
    Applied Thermal Engineering, 2014
    Co-Authors: Andres Z Mendiburu, Justo Jose Roberts, Joao Carvalho, Jose Luz Silveira
    Abstract:

    Abstract The objective of the present article is to assess and compare the performance of electricity generation systems integrated with Downdraft biomass Gasifiers for distributed power generation. A model for estimating the electric power generation of internal combustion engines and gas turbines powered by syngas was developed. First, the model determines the syngas composition and the lower heating value; and second, these data are used to evaluate power generation in Otto, Diesel, and Brayton cycles. Four synthesis gas compositions were tested for gasification with: air; pure oxygen; 60% oxygen with 40% steam; and 60% air with 40% steam. The results show a maximum power ratio of 0.567 kWh/Nm3 for the gas turbine system, 0.647 kWh/Nm3 for the compression ignition engine, and 0.775 kWh/Nm3 for the spark-ignition engine while running on synthesis gas which was produced using pure oxygen as gasification agent. When these three systems run on synthesis gas produced using atmospheric air as gasification agent, the maximum power ratios were 0.274 kWh/Nm3 for the gas turbine system, 0.302 kWh/Nm3 for CIE, and 0.282 kWh/Nm3 for SIE. The relationship between power output and synthesis gas flow variations is presented as is the dependence of efficiency on compression ratios. Since the maximum attainable power ratio of CIE is higher than that of SIE for gasification with air, more research should be performed on utilization of synthesis gas in CIE.

Andres Z Mendiburu - One of the best experts on this subject based on the ideXlab platform.

  • thermochemical equilibrium modeling of a biomass Downdraft gasifier constrained and unconstrained non stoichiometric models
    Energy, 2014
    Co-Authors: Andres Z Mendiburu, J A Carvalho, Rolando Zanzi, Christian J R Coronado, Jose Luz Silveira
    Abstract:

    The objective of this work is to develop a non-stoichiometric equilibrium model to study parameter effects in the gasification process of a feedstock in Downdraft Gasifiers. The non-stoichiometric equilibrium model is also known as the Gibbs free energy minimization method. Four models were developed and tested. First a pure non-stoichiometric equilibrium model called M1 was developed; then the methane content was constrained by correlating experimental data and generating the model M2. A kinetic constraint that determines the apparent gasification rate was considered for model M3 and finally the two aforementioned constraints were implemented together in model M4. Models M2 and M4 showed to be the more accurate among the four developed models with mean RMS (root mean square error) values of 1.25 each.

  • thermodynamic analysis and comparison of Downdraft Gasifiers integrated with gas turbine spark and compression ignition engines for distributed power generation
    Applied Thermal Engineering, 2014
    Co-Authors: Andres Z Mendiburu, Justo Jose Roberts, Joao Carvalho, Jose Luz Silveira
    Abstract:

    Abstract The objective of the present article is to assess and compare the performance of electricity generation systems integrated with Downdraft biomass Gasifiers for distributed power generation. A model for estimating the electric power generation of internal combustion engines and gas turbines powered by syngas was developed. First, the model determines the syngas composition and the lower heating value; and second, these data are used to evaluate power generation in Otto, Diesel, and Brayton cycles. Four synthesis gas compositions were tested for gasification with: air; pure oxygen; 60% oxygen with 40% steam; and 60% air with 40% steam. The results show a maximum power ratio of 0.567 kWh/Nm3 for the gas turbine system, 0.647 kWh/Nm3 for the compression ignition engine, and 0.775 kWh/Nm3 for the spark-ignition engine while running on synthesis gas which was produced using pure oxygen as gasification agent. When these three systems run on synthesis gas produced using atmospheric air as gasification agent, the maximum power ratios were 0.274 kWh/Nm3 for the gas turbine system, 0.302 kWh/Nm3 for CIE, and 0.282 kWh/Nm3 for SIE. The relationship between power output and synthesis gas flow variations is presented as is the dependence of efficiency on compression ratios. Since the maximum attainable power ratio of CIE is higher than that of SIE for gasification with air, more research should be performed on utilization of synthesis gas in CIE.

Harwin Saptoadi - One of the best experts on this subject based on the ideXlab platform.

  • comparative study of two small scale Downdraft Gasifiers in terms of continuous flammability duration of producer gas from rice husk and sawdust gasification
    International Journal of Renewable Energy Research, 2017
    Co-Authors: A A P Susastriawan, Harwin Saptoadi, T M Purnomo
    Abstract:

    In this work, two small scale throat-less Downdraft Gasifiers (Gasifier I & Gasifier II) are run on feedstocks of rice husk and sawdust at different runs set up. The runs aim to compare the two Gasifiers in terms of continuous flammability duration of producer gas. The result shows that maximum 32 minutes continuous flammability duration is obtained from set up C (Rice husk gasification with 1 st stage tuyer primary air and top hole secondary air) for the gasifier I and maximum 30 minutes continuous flammability duration is achieved from set up I (Rice husk-sawdust blend gasification, 5 th stage tuyer primary air, and 1 st stage tuyer initiation of gasification) for the gasifier II. For closed top set up, the gasifier II is better than the gasifier I in terms of continuous flammability duration of producer gas, either for rice husk or sawdust gasification.

  • small scale Downdraft Gasifiers for biomass gasification a review
    Renewable & Sustainable Energy Reviews, 2017
    Co-Authors: A A P Susastriawan, Harwin Saptoadi
    Abstract:

    Downdraft gasifier is very attractive for biomass gasification due to its easy fabrication and operation, and also due to low tar content in producer gas. However, drawbacks such as grate blocking, channeling, and bridging are found in the Downdraft Gasifiers, typically for feedstock with low bulk density. Another disadvantage is the Downdraft Gasifiers only suitable for feedstock with low moisture content. The design of the Gasifiers is an important parameter that affects their performance. Various works on design improvements have been done for enhancing the performance of the Gasifiers. This paper aims to review small-scale Downdraft Gasifiers for biomass gasification which is focused on design improvements and their effect on the performance of the Gasifiers. Many works from previous researchers have been studied and cited. The result shows that the design of the Gasifiers is an important parameter in gasification, besides biomass feedstock characteristics and process parameters.

A A P Susastriawan - One of the best experts on this subject based on the ideXlab platform.

  • comparative study of two small scale Downdraft Gasifiers in terms of continuous flammability duration of producer gas from rice husk and sawdust gasification
    International Journal of Renewable Energy Research, 2017
    Co-Authors: A A P Susastriawan, Harwin Saptoadi, T M Purnomo
    Abstract:

    In this work, two small scale throat-less Downdraft Gasifiers (Gasifier I & Gasifier II) are run on feedstocks of rice husk and sawdust at different runs set up. The runs aim to compare the two Gasifiers in terms of continuous flammability duration of producer gas. The result shows that maximum 32 minutes continuous flammability duration is obtained from set up C (Rice husk gasification with 1 st stage tuyer primary air and top hole secondary air) for the gasifier I and maximum 30 minutes continuous flammability duration is achieved from set up I (Rice husk-sawdust blend gasification, 5 th stage tuyer primary air, and 1 st stage tuyer initiation of gasification) for the gasifier II. For closed top set up, the gasifier II is better than the gasifier I in terms of continuous flammability duration of producer gas, either for rice husk or sawdust gasification.

  • small scale Downdraft Gasifiers for biomass gasification a review
    Renewable & Sustainable Energy Reviews, 2017
    Co-Authors: A A P Susastriawan, Harwin Saptoadi
    Abstract:

    Downdraft gasifier is very attractive for biomass gasification due to its easy fabrication and operation, and also due to low tar content in producer gas. However, drawbacks such as grate blocking, channeling, and bridging are found in the Downdraft Gasifiers, typically for feedstock with low bulk density. Another disadvantage is the Downdraft Gasifiers only suitable for feedstock with low moisture content. The design of the Gasifiers is an important parameter that affects their performance. Various works on design improvements have been done for enhancing the performance of the Gasifiers. This paper aims to review small-scale Downdraft Gasifiers for biomass gasification which is focused on design improvements and their effect on the performance of the Gasifiers. Many works from previous researchers have been studied and cited. The result shows that the design of the Gasifiers is an important parameter in gasification, besides biomass feedstock characteristics and process parameters.

Patrick Sharrock - One of the best experts on this subject based on the ideXlab platform.

  • Simulation of biomass char gasification in a Downdraft reactor for syngas production
    AIChE Journal, 2016
    Co-Authors: Augustina Ephraim, Victor Pozzobon, Olivier Louisnard, Doan Pham Minh, Ange Nzihou, Patrick Sharrock
    Abstract:

    A steady state, one-dimensional computational fluid dynamics model of wood char gasification in a Downdraft reactor is presented. The model is not only based on reaction kinetics and fluid flow in the porous char bed but also on equations of heat and mass conservation. An original OpenFOAM solver is used to simulate the model and the results are found to be in good agreement with published experimental data. Next, a sensitivity analysis is performed to study the influence of reactor inlet temperature and gas composition on char conversion, bed temperature profile and syngas composition. In addition, the evolution of the complex reaction mechanisms involved in mixed atmosphere gasification is investigated, and the most suitable operating parameters for controlling syngas composition are evaluated. Our simulation results provide essential knowledge for optimizing the design and operation of Downdraft Gasifiers to produce syngas that meets the requirements of various biofuel applications