| Coal gasification technology is one of the key means to account for energy sources, environment and energy safety in the future. However, there is plenty of high ash melting point coal in China which could not be gasified in almost all entrained flow bed gasifier currently, so it's imperative that a new coal gasification technology should be built out urgently. In coal gasification techniques, the gasifier is the key equipment which directly affects gasification characteristics, therefore flameless oxidant technology was applied to the design of new gasifier for high ash melting coal, and gasification characteristics in the gasifier were carried out by not only experiments under cold state and therma1 state, but also numerical simulations in this paper.Firstly, the all advanced types of dry feeding entrained flow bed gasifiers nowadays at home and abroad were summed up and classified, the structural and flow field characteristics, gasification reaction mechanism, temperature distributing inside the gasifier and the advantages and disadvantages of the the gasifier were detailedly analyzed; at the same time realization conditions, formation mechanism and implementation approaches of flameless oxidation technology also be explored in detail. So, a novel dry pulverized coal gasifier based on flameless oxidant which was applicable to high ash melting point coal was put forward, and the feasibility of high efficiency gasification and slag tapping for the coal on the gasifier were discussed.Secondly, cold state characteristics and aerodynamic field inside the experimental gasifier was tested using hot wire anemometer under three kind conditions, namely single nozzle tangential flow jet, double nozzles tangential flow jet symmetrically and staged-feeding four nozzles tangential flow jet symmetrically, according to the implementation approaches of flameless oxidation technology, so as to demonstrate the feasibility of flameless oxidation in the gasifier.Thirdly, a test system for coal gasifier was designed and built up, subsequently debug experiments were conducted. Then, gasification experiments of high ash melting point coal with dry pulverized coal feeding were carried out on the gasification test system, the flame images were observed to validate the feasibility of flameless gasification inside the gasifier, temperature distributing inner the gasifier and syngas components were measured under different [O]/[C] atom ratio and steam/coal ratio conditions. From these experimental results, the value range of key gasification parameters, including [O]/[C] atom ratio and steam/coal ratio mainly, could be obtained that will accumulate experiences for the subsequent research deeply.Fourthly, physical models and mathematical model of the gasifier were built, then three-dimensional numerical simulation of the gasifier for high ash melting point pulverized coal was conducted by using probability density function (PDF) model. From the simulation results, the veracity and feasibility of numeral gasification model could be verified by compared with the experimental results, the influence rules of [O]/[C] atom ratio and steam/coal ratio on gasification characteristics of high ash melting point coal could be drew, and the flow and components concentration field inner the gasifier could be study visually, that will provide evidences for optimal design further of the gasifier structure and gasification techniques.Finally, staged gasification was applied to the structure design of the gasifier, so a structure improved gasifier, namely staged gasifier based on flameless oxidation was put forward. Then the gasification numerical simulations of high ash melting point coal in the staged gasifier were conducted under different conditions, so as to analyze the effects of [O]/[C] atom ratio, steam/coal ratio and second stage reactants supply ratio on the gasification characteristics in the staged gasifier, all that will somewhat offer references for pilot test subsequently.
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