The Water Quenching Process For Coal Pyrolysis To Acetylene In Plasma Reactor

Producing acetylene by coal pyrolysis in plasma is attractive because it is a short, clean and efficient process with low-carbon and low-pollution. This thesis studies the water quenching process in the acetylene production by coal pyrolysis in plasma. A mathematical model which can describe the quenching process is proposed. A new annular-type quenching cooler is designed. The main contents in this thesis are as following.The chemical thermodynamic equilibrium of acetylene production by coal pyrolysis in plasma are studied using the method of Gibbs free energy. The calculated results indicate that the proper starting quenching temperature range for acetylene formation is 1700-2600K.A mathematical model which can describe the quenching process is proposed based on the Eulerian- Lagrangian method. In the model, the gas is regarded as the continuous phase, and the quenching water is regarded as the discrete phase.To solve the problem of the cylinder-type quencher that quenching water can't reach the center of the quencher, a new annular-type quencher is designed. The annular-type quencher solves the problem existed in the cylinder-type quencher, and its scaling-up effect is small. Furthermore, the appropriate starting quenching location can be found easily by changing the height of quenching core. The structure of the new quencher was determined based on the proposed mathematical model:two rows of nozzles were installed in the body and the core of the quencher, respectively; nozzles are installed vertically; the angles between the radial of the quencher and the quenching body or the core are both 40°; the horizontal distance between the core and the quencher is 100mm. The new annular-type quenching cooler is used in the 5MW pilot plant. The experimental results indicate that the concentration of acetylene using the annular-type quencher is much higher than that using the cylinder-type quencher.To prevent the core of the annular-type quencher from abrasion, a method is proposed where a hard cap is installed on the core of the quencher.