High-temperature air/steam gasification for medium or High calorific value sysgas production

摘要

Use of highly preheated gasifying agent (Air/steam) provides additional energy into the gasification process. This leads to a very uniform temperature profile in the gasifier, which can be called as Homogenous Gasifier. The developed homogenous gasifier includes two reactors: a homogenous gasifier with pebble-bed and a high-temperature air generator, using either a regenerative heater or a combustor with oxygen enhancement. Development, testing and numerical simulations of the THG in KTH have shown that based on the agent temperature, two distinct ignition modes are identified: the reaction-controlled and convective-controlled mode. The results also show increasing of the air temperature, it can be obtained a higher gasification rate, a fast ignition front rate, and a higher molar fractions of fuel gases (CO, H2 and CmHn), thus a higher LHV. Moreover, there exists a critical air temperature above which the preheating is no longer efficient if the gasification purpose is to maximise the yield of gaseous products. At a higher air flow rate, CO/CO2 ratio is increased. Again, the ignition front rate is increased. A increasing of the oxygen concentration leads to a larger peak value of the fuel gases concentrations, and a fast gasification rate, and larger ignition front rate. The biomass and plastic waste are tested and the characteristic is achieved. It demonstrated the flexible fuel capabilities of the gasifier design