Development of a Test Facility to Study the Agglomeration of Alkali Rich Biomass in Bubbling Fluidised Bed Gasification

The thermochemical process like gasification increases the energy density of biomass by converting it into a mixture of fuel gases such as hydrogen (H2), methane (CH4) and carbon monoxide(CO). Despite the fact that the bubbling fluidised bed gasification is a proven technology with fuel flexibility, high carbon conversion efficiency, and uniform temperature distribution in the reactor, it is prone to bed agglomeration when alkali rich biomasses are used. The product gas composition depends on operating parameters like equivalence ratio, temperature, bed material, and gasification medium. The reported work illustrates the design approach for developing a test facility to study agglomeration behaviour in fluidized bed gasification of biomass. The bubbling fluidised bed gasifier design is such that the biomass feed rate is restricted to 1–4 kg/h with sand as bed material, coffee husk as feedstock, and air as gasification medium. The designed reactor has a diameter of 7.6 cm and a height of 117.2 cm. The components such as the distributor plate, cyclone separator, and wind box are also designed. The sudden fluctuation in temperature and pressure across the bed reveals the agglomeration tendency. The instrumentation and measurement part of the proposed system facilitates the monitoring of all the operating parameters. The quality of product gas may be enhanced by developing gas cleaning arrangements, which falls in the future scope of the work.