0.2 MW Experimental Study On Preheated Combustion Of Pulverized Semi-coke

Coal is the main source of energy in China and China is the largest producer and consumer of coal around the word. Directly burning of coal has the problem of low combustion efficiency and causing serious environmental pollution at the same time. Pyrolysis is a way to granding utilization of coal and semi-coke powder is a byproduct of pyrolysis with the characteristics of less volatile, high ignition temperatures, difficulty in burning out.0.2 MW preheating combustion test rig was built by the support of the Strategic Priority Research Program of the Chinese Academy of Sciences with the project of the clean and efficient combustion demonstration of coal and semi-coke.0.2 MW preheating combustion test rig is used to study the preheating combustion characteristic of low volatile fuel semi-coke powder, analysising the influence of the different operating parameters.The experimental results show semi-coke powder can burn at 0.2 MW preheating combustion test rig steadily. Semi-coke powder can preheat itself to 850 ℃ with low air equivalence ratio in preheating chamber. Preheating chamber can provide preheated fuel to downward combustion chamber continuously. The primary air needed to preheat semi-coke to 850℃ at 0.2 MW preheating combustion test rig is 0.17, the necessary primary air is obvious decreasing comparing with 30 kW preheating test rig with primary air equivalence ratio of 0.37. When the test rig is larger, the needed primary air is lesser, which is beneficial to the engineering application of this technology on preheating combustion.Preheated fuel can burn well in the downward combustion chamber, the highest combustion efficiency is 98.6%. Secondary air equivalence ratio, location of tertiary air and excess air ratio can control the temperature distributions of downward combustion chamber. The maximum temperature difference can be controlled at 224℃. This test rig can run from 0.13 MW to 0.23 MW stable.The lowest NOx emission in the exhaust is 178 mg/m3 (6% O2). NOX emission is influenced by the air distribution. Primary air ratio increased, NOx emission decreased; secondary air ratio increased, NOx emission increased; location of tertiary moved down, NOX emmission decreased.The test results provide experimental data and theoretical foundation for the development of preheated combustion technology.