Research On The Atomization Characteristics And Mechanism Of Air-blast Nozzles And Development Of The CWS Burner For Gasification

Atomization is a process that the continuous liquid is distorted, breaks up, and finally becomes separated droplets with certain size distribution. Sprays are widely used in vary fields such as industry, agriculture, aviation, military and so on. High viscosity fuels (such as CWS, heavy oil) are usually atomized by air-blast atomizers. It is very important to study the characteristic and mechanism of the air-blast atomization. As key equipment in CWS gasification technologies, the characteristic and life-span of the fuel burner plays an important role in the operation. Most technical indexes of the gasification are related to the burner. At present, all the fuel atomizers (or burners) used in gasification industrial applications are three-channel ones, which structures are well combined with materials. But the shortage of such burners is critical, saying, bad atomization characteristic and short life-span. It would be much of practical value to develop a new novel atomizer.First, this paper introduces the status quo of gasification technology for CWS, describes the characteristics as well as structures of some gasification atomizers home and abroad. The requirements of CWS gasification for the fuel burner are given. A new idea is given that a two-channel partial internal-mix atomizer should be a CWS gasification burner.Secondly, the test system and the relevant instruments and apparatuses are presented. The paper then tells us some of the atomizing types for sprays as well as the status quo of the study progress for atomization mechanism around the world. The atomization characteristics of the two-channel external-mix air atomizer (both parallel type and convergent type with 30 degree), the two-channel partial internal-mix atomizer, and the three-channel air-blast atomizer are investigated experimentally. The process of destabilization, distortion, breakup, and finally atomization for the round jet is observed when it is injected into a room either with or without atomizing gas medium.At last, the gasification theory for CWS is stated briefly. In special the oxygen-slurry ratio in gasification is calculated theoretically. Some atomization experiments of partial internal-mix air-blast atomizers are carried out in order to study the effects of both the structure and the sizes on the SMD. The ones which perform the best are thus selected. A trial is also carried out to simulate the internal and external flow fields of such atomizer using the Fluent software.