The Experts below are selected from a list of 177 Experts worldwide ranked by ideXlab platform
John R. Grace - One of the best experts on this subject based on the ideXlab platform.
-
Biomass granular screw feeding: An experimental investigation
Biomass and Bioenergy, 2011Co-Authors: Jianjun Dai, John R. GraceAbstract:Abstract Successful feeding is critical to biomass utilization processes, but difficult due to the heterogeneity, physical properties and moisture content of the particles. The objectives of the present study were to find the mechanisms of bLockage in screw feeding and to determine the effects of particle mean size (0.5–15 mm), size distribution, shape, moisture content (10–60%), density and compressibility on biomass particle feeding at room temperature. Wood pellets, sawdust, hog fuel and wood shavings were tested in a screw feeder/Lock Hopper system previously employed to feed sawdust into a pilot-scale circulating fluidized-bed gasifier. Experimental results showed that large particles, wide size distributions, large bulk densities and high moisture contents generally led to larger torque requirements for screw feeding. The “choke section” and seal plug play important roles in determining the torque requirements.
-
Biomass screw feeding with tapered and extended sections
Powder Technology, 2008Co-Authors: Jianjun Dai, John R. GraceAbstract:Successful feeding is critical to biomass utilization processes such as gasification and combustion, but feeding is difficult due to the adverse effects of heterogeneity, physical characteristics and moisture content of the particles. The objectives of the present study were to define bLockage mechanisms and plug seal with the aid of tapered and extended sections. Wood pellets, sawdust, hog fuel and wood shavings were delivered by a screw feeder/Lock Hopper system. The experimental results showed that tapered and extended sections increased torque requirements significantly while improving the plug seal to the reactor, with performance depending on biomass physical properties and screw feeder characteristics.
-
A model for biomass screw feeding
Powder Technology, 2008Co-Authors: Jianjun Dai, John R. GraceAbstract:Successful feeding is critical to biomass utilization processes, but trouble-free delivery is difficult due to particle heterogeneity, physical characteristics and moisture content. A model, extended from previous models in the literature, is proposed to delineate what limits screw feeding in terms of the mechanisms of bLockage and to predict torque requirements for biomass materials. Predictions on feeding of wood pellets, sawdust, hog fuel and wood shavings in a screw feeder/Lock Hopper system are in good agreement with our earlier experimental findings. The choke section and seal plug are shown to play important roles in determining the torque requirements for biomass screw feeding, although they are rarely mentioned in previous research on screw feeding of other materials.
Xin Gong - One of the best experts on this subject based on the ideXlab platform.
-
Characteristics of Different Sized Slag Particles from Entrained-Flow Coal Gasification
Energy & Fuels, 2016Co-Authors: Chanchan Pan, Qinfeng Liang, Xiaolei Guo, Zhenghua Dai, Haifeng Liu, Xin GongAbstract:Gasification slags are byproducts of the coal gasification process, including fine slags (slags from filter) and coarse slags (slags from Lock Hopper). The characteristics of gasification slags with different particle sizes were investigated by the loss-on-ignition (LOI) method, scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS), pore structure analysis, X-ray diffractometry (XRD), and X-ray fluorescence spectrometry (XRF). The relationships between the particle size and the characteristics of slags, which include residual carbon content, surface characteristics, pore structure, crystal mineral content, and ash composition, were analyzed and obtained. For fine slags, carbon content, specific surface area, porosity, and crystal content increase with particle size. For coarse slags, medium sized (105–280 μm) particles contain the most residual carbons and crystal minerals, followed by the smaller (0–105 μm) particles. Si/Al/Ca/Mg/K tends to concentrate in larger coarse slags, while...
Jianjun Dai - One of the best experts on this subject based on the ideXlab platform.
-
Biomass granular screw feeding: An experimental investigation
Biomass and Bioenergy, 2011Co-Authors: Jianjun Dai, John R. GraceAbstract:Abstract Successful feeding is critical to biomass utilization processes, but difficult due to the heterogeneity, physical properties and moisture content of the particles. The objectives of the present study were to find the mechanisms of bLockage in screw feeding and to determine the effects of particle mean size (0.5–15 mm), size distribution, shape, moisture content (10–60%), density and compressibility on biomass particle feeding at room temperature. Wood pellets, sawdust, hog fuel and wood shavings were tested in a screw feeder/Lock Hopper system previously employed to feed sawdust into a pilot-scale circulating fluidized-bed gasifier. Experimental results showed that large particles, wide size distributions, large bulk densities and high moisture contents generally led to larger torque requirements for screw feeding. The “choke section” and seal plug play important roles in determining the torque requirements.
-
Biomass screw feeding with tapered and extended sections
Powder Technology, 2008Co-Authors: Jianjun Dai, John R. GraceAbstract:Successful feeding is critical to biomass utilization processes such as gasification and combustion, but feeding is difficult due to the adverse effects of heterogeneity, physical characteristics and moisture content of the particles. The objectives of the present study were to define bLockage mechanisms and plug seal with the aid of tapered and extended sections. Wood pellets, sawdust, hog fuel and wood shavings were delivered by a screw feeder/Lock Hopper system. The experimental results showed that tapered and extended sections increased torque requirements significantly while improving the plug seal to the reactor, with performance depending on biomass physical properties and screw feeder characteristics.
-
A model for biomass screw feeding
Powder Technology, 2008Co-Authors: Jianjun Dai, John R. GraceAbstract:Successful feeding is critical to biomass utilization processes, but trouble-free delivery is difficult due to particle heterogeneity, physical characteristics and moisture content. A model, extended from previous models in the literature, is proposed to delineate what limits screw feeding in terms of the mechanisms of bLockage and to predict torque requirements for biomass materials. Predictions on feeding of wood pellets, sawdust, hog fuel and wood shavings in a screw feeder/Lock Hopper system are in good agreement with our earlier experimental findings. The choke section and seal plug are shown to play important roles in determining the torque requirements for biomass screw feeding, although they are rarely mentioned in previous research on screw feeding of other materials.
Chanchan Pan - One of the best experts on this subject based on the ideXlab platform.
-
Characteristics of Different Sized Slag Particles from Entrained-Flow Coal Gasification
Energy & Fuels, 2016Co-Authors: Chanchan Pan, Qinfeng Liang, Xiaolei Guo, Zhenghua Dai, Haifeng Liu, Xin GongAbstract:Gasification slags are byproducts of the coal gasification process, including fine slags (slags from filter) and coarse slags (slags from Lock Hopper). The characteristics of gasification slags with different particle sizes were investigated by the loss-on-ignition (LOI) method, scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS), pore structure analysis, X-ray diffractometry (XRD), and X-ray fluorescence spectrometry (XRF). The relationships between the particle size and the characteristics of slags, which include residual carbon content, surface characteristics, pore structure, crystal mineral content, and ash composition, were analyzed and obtained. For fine slags, carbon content, specific surface area, porosity, and crystal content increase with particle size. For coarse slags, medium sized (105–280 μm) particles contain the most residual carbons and crystal minerals, followed by the smaller (0–105 μm) particles. Si/Al/Ca/Mg/K tends to concentrate in larger coarse slags, while...
James M. Craven - One of the best experts on this subject based on the ideXlab platform.
-
Investigation into the Flow Properties of Coarse Solid Fuels for Use in Industrial Feed Systems
Journal of Powder Technology, 2015Co-Authors: James M. Craven, Jim Swithenbank, Vida N. SharifiAbstract:Material feeding and handling systems have been cited as one of the most common causes of process downtime where thermochemical conversion processes are concerned. New and emerging fuels come in a variety of forms, and if such fuels are to be deployed widely it is imperative that material feeding and handling systems are designed appropriately. This study proposes an approach for designing material feeding and handling systems for use with coarse solid fuels. The data obtained from this study indicates particle size to be one of the key issues affecting the flowability of bulk solids further to the uniformity in particle shape. Coarse bulk solid samples were shown to flow more freely than their milled and pulverised counterparts, generating higher degrees of flowability. The results from this study were also applied to a new feed system used for feeding solid fuels to high pressure processes named the Hydraulic Lock Hopper. In this study the Hydraulic Lock Hopper demonstrated the feeding of wood pellets, torrefied spruce pellets, and ground anthracite coal grains against a pressure of 25 barg in two modes of operation. Energy savings compared to conventional Lock Hopper systems were recorded in the region of 80%.
-
Energy efficient solids feed system for high pressure processes
2014Co-Authors: James M. CravenAbstract:A new system for efficiently feeding solid fuels to high pressure processes has been developed over the course of this PhD study. The system, named the Hydraulic Lock Hopper (HLH), takes the form of a new Lock Hopper that utilises water as an incompressible fluid during the compression stage. It disposes of the need for inert gas or gas compressors as is required by conventional Lock Hopper systems, and vastly increases their operational efficiency. The HLH has demonstrated the feeding of a range of fuels including wood pellets, torrefied spruce pellets and ground anthracite grains to pressures as high as 25 barg. Two modes of operation have been developed, one whereby the energy requirement to feed is minimised (Mode 1), and another whereby the volume of high pressure gas vented to the atmosphere is reduced to near nil (Mode 2). In addition to this, the HLH has been developed to operate without the forward leakage of air in order to minimise explosive atmospheres.
-
Development of a novel solids feed system for high pressure gasification
Fuel Processing Technology, 2014Co-Authors: James M. Craven, Jim Swithenbank, Vida N. Sharifi, D. Peralta-solorio, G. Kelsall, P. SageAbstract:Abstract The Hydraulic Lock Hopper (HLH) embodies a high pressure dry feed system that uses water as an incompressible fluid to bring about compression. No pressurising gas is required, so commonly used inert gases such as nitrogen and carbon dioxide are conserved. The HLH has successfully demonstrated the feeding of solid fuels such as wood pellets to pressures as high as 25 barg in two modes of operation. Energy requirements of 15.51 kJ/kg (Mode 1) and 20.61 kJ/kg (Mode 2) have been recorded which translate to significant energy savings of 81.9% and 75.9% compared to conventional Lock Hoppers. Energy savings have been projected to increase for Mode 2 where Lock gas contamination with syngas takes place, and the mass flow rate has been shown to operate independently of pressure varying between 2 and 2.5 tonnes/day. The HLH has also been shown to have a negligible effect on the fuel moisture content with moisture content increases being recorded to be consistently less than 1 wt.%.
