Development and Evaluation of Performance of a Bench Scale Gasi er for Sub-Bituminous Coal

Abstract

Trends internationally have shown that about 60% of power in developed coun- tries of Europe, America and Asia is from coal. Combustion of coal generates huge quantities of gaseous emissions. The rules governing emissions have become more stringent and therefore, alternative techniques of coal utilization are required for clean power generation. Recent research is geared towards higher e ciency coal gasi cation plants as well as fuel synthesis from syngas. In this research a bench scale gasi er was designed, fabricated and its performance analyzed. The main aim of the research was to gasify sub-bituminous coal under uidized conditions to produce a combustible gas whose composition was to be analyzed and optimum working conditions established. Air ow rate was varied and the reactor temper- ature and gas composition were measured at each ow rate. Results from this research showed a 13.73% reduction in CO concentration with increase in air ow rate from 1.0 to 2.5 m3/min. CO reduction was attributed to fact that more air enhanced conversion of CO to CO2. As the air ow rate was increased from 1.0 to 2.5 m3/min, the HHV of the syngas was observed to decrease from 5.667 to 4.106MJ/Nm3. This was attributed to the reduction of CO and the increase of nitrogen composition which do not add to the calori c value of the syngas. The cold gas e ciency(CGE) and carbon conversion e ciency (CCE) of the gasi er were obtained as 64.29% and 89.89% respectively. This research can be applied in power generation by channeling the syngas produced to power gas turbines and engines. The research gives insightful information that can contribute to improved design of gasi cation systems.