Pilot Study On Gas Characteristics Of Coal Catalytic Gasification With H₂O/Air Atmosphere

With the increasing consumption and unreasonable utilization of global energy,environmental pollution problems are becoming more and more serious.Therefore,optimizing structure and improving efficiency and clean utilization of energy are important routes for economic and social sustainable development.As a leading technology,Coal gasification is one of the effective technologies for achieving coal clean utilization.Compared with traditional coal gasification,catalytic gasification of coal has many advantages,such as reducing gasification temperature,increasing gasification rate and adjustable gas composition.The gasification characteristics of K₂CO₃,Ca CO₃and K/Ca composite catalyst for Shizuishan coal under H₂O/air atmosphere were studied in pilot fixed bed equipment..The effects of catalyst loading,gasification temperature and steam flow rate on coal gas components and gas calorific value were systematically investigated.The following conclusions were acquired:coal is gasified under H₂O/air atmosphere,the main gas composition is H₂and CO,and the amount of CH₄and CO₂is less,the catalyst is beneficial to increase the ratio of H₂and CO in gasification gas.But the amount of CO is increased faster by K₂CO₃.The catalyst has a saturated load.The optimum loading of potassium is 8 wt%.The optimal loading of calcium is 2wt%,For the composite catalyst,the hydrogen gas quantities produced is the largest under SZ-8K-4Ca.The temperature has a great influence for the catalytic gasification of coal.Under the optimal loading,the amount of H₂of the potassium,calcium and composite catalyst attains the largest at 750?,800?,700?,respectively.Compared with the one-component catalyst,the composite catalyst can reduce the coal gasification temperature about 50 to 100?,.Water vapor can increase the relative content of H₂in gas components,but the change of CO is not obvious.When steam flow exceeds 10 m L/min,the increasing of H₂is not obvious.The calorific value of gas is related to the load of catalyst,temperature and steam flow,catalyst is beneficial to increase the calorific value of gas;Potassium carbonate is well dispersed on coal char surface,the calcium carbonate is agglomerated,composite catalyst is evenly distributed.Ca S and Ca(Al₂Si₂O₈)are formed by the reaction of calcium with minerals during the gasification process,calcium has a certain inhibitory effect for potassium inactivation.At 700°C,the hydrogen gas quantities produced of SZ-8K-4Ca is 1.4 times that of raw coal,1.1 times that of SZ-8K and 1.3 times that of SZ-2Ca.At 750°C,the hydrogen gas quantities and carbon monoxide produced by SZ-8K are 1.14 times and 1.28 times that of SZ-2Ca,respectively.The increment of H₂and CO by Ca CO₃is less than that of K₂CO₃.