Syngas

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Nimit Nipattummakul - One of the best experts on this subject based on the ideXlab platform.

  • high temperature steam gasification of wastewater sludge
    Applied Energy, 2010
    Co-Authors: Islam Ahmed, Nimit Nipattummakul, Somrat Kerdsuwan, Ashwani K. Gupta
    Abstract:

    High temperature steam gasification is one of the most promising, viable, effective and efficient technology for clean conversion of wastes to energy with minimal or negligible environmental impact. Gasification can add value by transforming the waste to low or medium heating value fuel which can be used as a source of clean energy or co-fired with other fuels in current power systems. Wastewater sludge is a good source of sustainable fuel after fuel reforming with steam gasification. The use of steam is shown to provide value added characteristics to the sewage sludge with increased hydrogen content as well total energy. Results obtained on the Syngas properties from sewage sludge are presented here at various steam to carbon ratios at a reactor temperature of 1173 K. Effect of steam to carbon ratio on Syngas properties are evaluated with specific focus on the amounts of Syngas yield, Syngas composition, hydrogen yield, energy yield, and apparent thermal efficiency. The apparent thermal efficiency is similar to cold gas efficiency used in industry and was determined from the ratio of energy in Syngas to energy in the solid sewage sludge feedstock. A laboratory scale semi-batch type gasifier was used to determine the evolutionary behavior of the Syngas properties using calibrated experiments and diagnostic facilities. Results showed an optimum steam to carbon ratio of 5.62 for the range of conditions examined here for Syngas yield, hydrogen yield, energy yield and energy ratio of Syngas to sewage sludge fuel. The results show that steam gasification provided 25% increase in energy yield as compared to pyrolysis at the same temperature.

Sang Jun Yoon - One of the best experts on this subject based on the ideXlab platform.

  • Syngas production through gasification of coal water mixture and power generation on dual fuel diesel engine
    Journal of The Energy Institute, 2018
    Co-Authors: Gunung Oh, Ho Won Ra, Sung Min Yoon, Sang Jun Yoon
    Abstract:

    Abstract In the present study, a Syngas was produced by preparing coal water mixtures of two different concentrations and gasifying the coal water mixtures. An entrained-flow gasifier of 1 ton/day scale was used and, after undergoing a purification process, the produced Syngas was applied to a modified diesel engine for power generation. As the gasification temperature increased, the carbon conversion and the cold gas efficiency were found to increase. In the composition of the produced Syngas, the content of H2 remained constant, that of CO increased, and those of CO2 and CH4 decreased. The carbon conversion increased with equivalence ratio. A maximum cold gas efficiency of 66.1% was found at the equivalence ratio of 0.43. N2 was additionally supplied to verify the gasification characteristics depending on the gas feed flow rate. The optimum feed flow rate was verified at different slurry concentrations and equivalence ratio. The produced Syngas was supplied to a modified diesel engine and operated depending on the Syngas feed flow rate and the engine operation conditions. The brake thermal efficiency of the engine was constant regardless of the Syngas feed flow rate. The diesel engine showed high efficiency despite the mixing of the Syngas.

  • gasification and power generation characteristics of woody biomass utilizing a downdraft gasifier
    Biomass & Bioenergy, 2011
    Co-Authors: Sang Jun Yoon
    Abstract:

    Abstract Energy utilization from biomass resources has started to attract public attention as a method to reduce CO 2 emissions. In this study, the characteristics of Syngas production from biomass gasification were investigated in a downdraft gasifier that was combined with a small gas engine system for power generation. Syngas temperatures from the gasifier were maintained at a level of 700–1000 °C. When the air ratio for gasification was 0.3–0.35, the low heating value of Syngas was 1100–1200 kcal Nm −3 and the cold gas efficiency 69–72%. Tar concentration in raw Syngas was around 3.9–4.4 g Nm −3 . Syngas combustion in the gas engine after purification showed that HC concentration was below 200 ppm, and NOx concentration was below 40 ppm in the exhaust gas.

Ashwani K. Gupta - One of the best experts on this subject based on the ideXlab platform.

  • high temperature steam gasification of wastewater sludge
    Applied Energy, 2010
    Co-Authors: Islam Ahmed, Nimit Nipattummakul, Somrat Kerdsuwan, Ashwani K. Gupta
    Abstract:

    High temperature steam gasification is one of the most promising, viable, effective and efficient technology for clean conversion of wastes to energy with minimal or negligible environmental impact. Gasification can add value by transforming the waste to low or medium heating value fuel which can be used as a source of clean energy or co-fired with other fuels in current power systems. Wastewater sludge is a good source of sustainable fuel after fuel reforming with steam gasification. The use of steam is shown to provide value added characteristics to the sewage sludge with increased hydrogen content as well total energy. Results obtained on the Syngas properties from sewage sludge are presented here at various steam to carbon ratios at a reactor temperature of 1173 K. Effect of steam to carbon ratio on Syngas properties are evaluated with specific focus on the amounts of Syngas yield, Syngas composition, hydrogen yield, energy yield, and apparent thermal efficiency. The apparent thermal efficiency is similar to cold gas efficiency used in industry and was determined from the ratio of energy in Syngas to energy in the solid sewage sludge feedstock. A laboratory scale semi-batch type gasifier was used to determine the evolutionary behavior of the Syngas properties using calibrated experiments and diagnostic facilities. Results showed an optimum steam to carbon ratio of 5.62 for the range of conditions examined here for Syngas yield, hydrogen yield, energy yield and energy ratio of Syngas to sewage sludge fuel. The results show that steam gasification provided 25% increase in energy yield as compared to pyrolysis at the same temperature.

Robert C Brown - One of the best experts on this subject based on the ideXlab platform.

  • enhancing mass transfer and ethanol production in Syngas fermentation of clostridium carboxidivorans p7 through a monolithic biofilm reactor
    Applied Energy, 2014
    Co-Authors: Yanwen Shen, Robert C Brown
    Abstract:

    Syngas fermentation is a promising process for producing fuels and chemicals from lignocellulosic biomass. Currently Syngas fermentation faces several engineering challenges, with gas-to-liquid mass transfer limitation representing the major bottleneck. The aim of this work is to evaluate the performance of a monolithic biofilm reactor (MBR) as a novel reactor configuration for Syngas fermentation. The volumetric mass transfer coefficient (kLa) of the MBR was evaluated in abiotic conditions within a wide range of gas flow rates (i.e., gas velocity in monolithic channels) and liquid flow rates (i.e., liquid velocity in the channels). The kLa values of the MBR were higher than those of a controlled bubble column reactor (BCR) in certain conditions, due to the slug flow pattern in the monolithic channels. A continuous Syngas fermentation using Clostridium carboxidivorans P7 was conducted in the MBR system under varying operational conditions, with the variables including Syngas flow rate, liquid recirculation between the monolithic column and reservoir, and dilution rate. It was found that the Syngas fermentation performance – measured by such parameters as Syngas utilization efficiency, ethanol concentration and productivity, and ratio of ethanol to acetic acid – depended not only on the mass transfer efficiency but also on the biofouling or abrading of the biofilm attached on the monolithic channel wall. At a condition of 300mL/min of Syngas flow rate, 500mL/min of liquid flow rate, and 0.48day−1 of dilution rate, the MBR produced much higher Syngas (CO/H2) utilization efficiency and much greater metabolite (ethanol/acetic acid) productivity than what was obtained using a traditional bubble column reactor. The study demonstrates the great potential of MBR as a promising reactor configuration for Syngas fermentation with high mass transfer efficiency, low energy consumption, and high metabolite productivity.

  • Syngas fermentation of clostridium carboxidivoran p7 in a hollow fiber membrane biofilm reactor evaluating the mass transfer coefficient and ethanol production performance
    Biochemical Engineering Journal, 2014
    Co-Authors: Yanwen Shen, Robert C Brown
    Abstract:

    Abstract Gasification followed by Syngas fermentation is a unique hybrid process for converting lignocellulosic biomass into fuels and chemicals. Current Syngas fermentation faces several challenges with low gas–liquid mass transfer being one of the major bottlenecks. The aim of this work is to evaluate the performance of hollow fiber membrane biofilm reactor (HFM-BR) as a reactor configuration for Syngas fermentation. The volumetric mass transfer coefficient (KLa) of the HFM-BR was determined at abiotic conditions within a wide range of gas velocity/flowrate passing through the hollow fiber lumen and liquid velocity/flowrate passing through the membrane module shell. The KLa values of the HFM-BR were higher than most reactor configurations such as stir tank reactors and bubble columns. A continuous Syngas fermentation of Clostridium carboxidivorans P7 was implemented in the HFM-BR system at different operational conditions, including the Syngas flow rate, liquid recirculation between the module and reservoir, and the dilution rate. It was found that the Syngas fermentation performance such as Syngas utilization efficiency, ethanol concentration and productivity, and ratio of ethanol to acetic acid depended not only on the mass transfer efficiency but also the characteristics of biofilm attached on the membrane module (biofouling or abrading of the biofilm). The HFM-BR results in a highest ethanol concentration of 23.93 g/L with an ethanol to acetic acid ratio of 4.79. Collectively, the research shows the HFM-BR is an efficient reactor system for Syngas fermentation with high mass transfer.

Fanhe Kong - One of the best experts on this subject based on the ideXlab platform.

  • high pressure chemical looping reforming processes system analysis for Syngas generation from natural gas and reducing tail gases
    Energy & Fuels, 2018
    Co-Authors: Peter Sandvik, William K Wang, Mandar Kathe, Fanhe Kong
    Abstract:

    Reforming technologies produce Syngas that serves as an important intermediate in the production of fuels and chemicals in the chemical and petrochemical industry. Only recently has reforming technology based on the chemical looping concept been attempted. Most chemical looping studies have been performed under ambient pressure conditions, but most processes that use Syngas operate at an elevated pressure. Understanding the effect that pressure has on Syngas generation in a chemical looping reactor is essential to the design of the overall system. This study characterizes and compares the effect of pressures on Syngas yields under various chemical looping reforming operating conditions. Specifically, in this study, an iron-based oxygen carrier is used for the chemical looping partial oxidation reaction of methane to form Syngas. The equilibrium simulation is of direct relevance to process applications, as demonstrated by the methane and metal oxide co-current reactor system, where in previous studies, exp...

  • High-Pressure Chemical Looping Reforming Processes: System Analysis for Syngas Generation from Natural Gas and Reducing Tail Gases
    2018
    Co-Authors: Pete Sandvik, Mandar Kathe, William Wang, Fanhe Kong
    Abstract:

    Reforming technologies produce Syngas that serves as an important intermediate in the production of fuels and chemicals in the chemical and petrochemical industry. Only recently has reforming technology based on the chemical looping concept been attempted. Most chemical looping studies have been performed under ambient pressure conditions, but most processes that use Syngas operate at an elevated pressure. Understanding the effect that pressure has on Syngas generation in a chemical looping reactor is essential to the design of the overall system. This study characterizes and compares the effect of pressures on Syngas yields under various chemical looping reforming operating conditions. Specifically, in this study, an iron-based oxygen carrier is used for the chemical looping partial oxidation reaction of methane to form Syngas. The equilibrium simulation is of direct relevance to process applications, as demonstrated by the methane and metal oxide co-current reactor system, where in previous studies, experimental product yields were shown to be appropriately represented by equilibrium conditions. The results of Syngas generation at 1 atm are used in this study as the basis for comparison to those obtained under pressurized conditions. The isothermal Syngas generation is first examined qualitatively and quantitatively for pressures ranging from 1 to 30 atm. The adiabatic Syngas generation is then examined under autothermal operating conditions. The sensitivity studies are performed to describe the changes in product yields as the temperature and pressure along with steam and CO2 inputs are varied. The results of the analysis illustrate the various competing factors that dictate the high-pressure Syngas yield and purity. The study also provides insight into choice of operating conditions that enable thermodynamic Syngas yields at higher pressure to be comparable to those at atmospheric pressures