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US 5,516,345 AGranted
Latent heat-ballasted gasifier method
AssigneeIowa State University Research Foundation, Inc.
InventorRobert C. Brown
Life of this patent
Estimating the term…
Abstract
A latent heat-ballasted gasifier suitable for converting biomass, coal, or low-quality fuels into a producer gas. Latent heat is stored in the reactor in ballasts containing a metal alloy with a melting point approximate the pyrolysis temperatures of the fuel. A fluidized bed reactor is used to enhance heat transfer between the latent heat material and the fuel. The latent heat-ballasts allows the reactor to be operated in a quasi-steady mode rather than a batch operation employed in the prior designs.
Claims17
A method for gasifying fuel comprising the steps of:
- providing a reactor vessel having a top portion and a bottom portion, a fluidization chamber in the reactor vessel, a plurality of ballast housings arranged in the fluidization chamber to permit generally uniform dispersion of a fuel therebetween, the ballast housings containing a material with a melting point greater than a pyrolysis temperature, a compressed air source in fluid communication with an inlet port proximate the bottom portion of the vessel, an exhaust port in fluid communication with the vessel proximate the top portion, a steam source in fluid communication with the inlet port, and a fuel port in fluid communication with the vessel proximate the top portion for introducing fuel to be gasified into the fluidization chamber;
- introducing a particulate material into the fluidization chamber;
- introducing compressed air and a gaseous fuel into the fluidization chamber;
- burning a gaseous fuel in the fluidization chamber during a cold-start phase to create a fluidized reactor bed;
- terminating the flow of the gaseous fuel when the fluidization chamber reaches a first predetermined temperature;
- burning fuel, in the fluidization chamber, introduced through the fuel port during a combustion phase until the fluidization chamber reaches a second predetermined temperature, the second predetermined temperature being above the melting point of the material in the ballasts;
- terminating the flow of compressed air;
- and
- initiating a flow of steam through the inlet port during a pyrolysis phase, the heat energy evolved from the material during a transition from a liquid state to a solid state providing heat energy for pyrolyzing the fuel.
6 more elements
A method for gasifying fuel comprising the steps of:
- providing a reactor vessel having a top portion and a bottom portion, a fluidization chamber in the reactor vessel, a plurality of ballast housings arranged in the fluidization chamber to permit generally uniform dispersion of a fuel therebetween, the ballast housings containing a material with a melting point greater than a pyrolysis temperature, an inlet port in fluid communication with the vessel proximate the bottom portion, an exhaust port in fluid communication with the vessel proximate the top portion, a steam source in fluid communication with the inlet port, and a fuel port in fluid communication with the vessel proximate the top portion for introducing fuel to be gasified into the fluidization chamber;
- heating the fluidization chamber to a first predetermined temperature during a cold-start phase;
- introducing compressed air through the inlet port and fuel through the fuel port, into the fluidization chamber;
- burning the fuel in the fluidization chamber during a combustion phase until the fluidization chamber reaches a second predetermined temperature, the second predetermined temperature being above the melting point of the material in the ballasts;
- terminating the flow of compressed air;
- and
- initiating a flow of steam through the inlet port during a pyrolysis phase so that the latent heat in the ballasts provides energy to convert the fuel by pyrolysis into a gaseous fuel.
4 more elements
A method for gasifying fuel comprising the steps of:
- arranging a plurality of ballast housings in a fluidization chamber to permit the uniform dispersion of a fuel therebetween;
- introducing a particulate material into the fluidization chamber;
- introducing compressed air and a gaseous fuel into the fluidization chamber;
- burning a gaseous fuel in the fluidization chamber during a cold-start phase to create a fluidized reactor bed;
- terminating the flow of the gaseous fuel when the fluidization chamber reaches a first predetermined temperature;
- burning fuel in the fluidization chamber during a combustion phase until the fluidization chamber reaches a second predetermined temperature, the second predetermined temperature being above a melting point of a substance in the ballast housings;
- terminating the flow of compressed air;
- and
- initiating a flow of steam through an inlet port during a pyrolysis phase, heat energy evolved from the substance during a transition from a liquid state to a solid state providing heat energy for pyrolyzing the fuel.
6 more elements
Dependencies are inferred from the claim text.