Experimental Investigation Of Non-equilibrium Plasma Assisted Combustion Of Low BTU Fuels

As the implementation of the policy of "energy saving and emission reduction" by the government, the steel industry need to find a more efficient way of using of low-BTU gas fuels. Low-BTU gas fuel is difficult to be ignited, and the flame is extremely unstable, and easily blown off. Non-equilibrium plasma assisted combustion technology might be a potential way to achieve reliable ignition and flame stabilization. Non-equilibrium plasma is generated by an electrical discharge through working gas (fuel, oxidant, or combustible mixture). The production of atoms, ions, and active radicals can significantly promote the process of chemical reactions.This paper mainly focuses on reliable ignition and flame stabilization of low-BTU gas fuels through the use of non-equilibrium plasma generated by an electrical discharge. First, an electrical discharge is designed to generate plasma. We learn the characteristics of the discharge, and analyze the production of active species in the discharge field. Then, we use the plasma generated by the discharge assisted the combustion process of low-BTU fuels. The changes of ignition ability, blow-off limits, flame speed, combustion efficiency and flame structure are observed. In order to analyze the influence of plasma deeply, we establish the numerical model of plasma assisted combustion process. Based on results of experiments and numerical simulation, mechanisms of plasma assisted combustion are ascertained. Finally, a plasma swirler is designed and the experiments are carried out to verify the feasibility of using plasma swirler to control diffusion flame.Main conclusions in this paper are below:1. Dielectric barrier discharge (DBD) can generate large volume, high concentration non-equilibrium plasma at atmosphere pressure.2. With the support of DBD plasma, the combustion characteristics of low BTU-fuels are improved a lot, including:more reliable ignition, wider blow-off limits, increased flame speed, and higher flame temperature.3. Mechanisms of plasma assisted combustion are ascertained to be results of raise of temperature and acceleration of chemical reactions.4. The plasma swirler can enhance combustion stability through ionizing the air to produce active free radical and promoting the swirling air.