Category Archives: Biomass Gasification and Pyrolysis

Supercritical Water Oxidation

Supercritical water that exhibits complete miscibility with oxygen is a homo­geneous reaction medium for the oxidation of organic molecules. This feature of SCW allows oxidation of harmful or toxic substances at low temperature in a process known as supercritical water oxidation (SCWO) or cold combustion. In a typical SCWO unit, the entire mixture (water, oxygen, and waste) remains as a […]

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8.4 BIOMASS FEEDERS

Based on the type of biomass, feeders can be divided into two broad groups: (1) those for harvested biomass and (2) those for nonharvested biomass. Harvested fuels include long and slender plants like straw, grass, and bagasse, which carry considerable amounts of moisture. Examples of nonhar — vested fuels are wood chips, rice husk, shells, barks, and pruning. These fuels […]

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CFD Models

Computational fluid dynamics can have an important role in the modeling of a fluidized-bed gasifier. A CFD-based code involves a solution of conservation of mass, momentum, species, and energy over a defined domain or region. The equations can be written for an element, where the flux of the just-mentioned quantities moving in and out of the element is considered with […]

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Catalyst Selection

The choice of catalyst influences reactor temperature, product distribution, and plugging potential. Section 7.4.2 discussed the catalysts used in SCW gasification. They are selected on the basis of the desired product. Catalyst deactivation is an issue assigned to most catalyzed reactions because the deac­tivated catalysts must be regenerated. If they are deactivated because of carbon deposits, as happens in a […]

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