Technical Research Of The Adjusting And Controlling Mechanism Of The Underground Gasification Of Coal And Computer Emulation

After more than half a century's research and practice, underground gasification of coal has gained cheerful success. But mass productive development has not finally achieved. Without adjusting and controlling measures or with obsolete measures, the amount of flammable components is very low in the mixed gas; the heat value of gas in the mixed gas is relatively low. The density of flammable gas, components and variety of heat value are very different from the gasification on the ground gasification furnace; The field of the oxidize zone, the deoxidize zone and the carbonization zone, which are simply called 'three zones', are changing as the proceeding of the burning zone, along with the waving of the density of flammable gas and the heat value, which makes the production of gas unstable. Generally there are three instabilities: instability of heat value, flammable component parts and the amount of gas generation.In order to solve this problem, researchers from different countries have made attempts on three aspects: 1) Providing wind conversely to adjust and control the scare of deoxidize zone and carbonization and desiccation zone caused by the coming near of the 'three zone' to the exit; 2) burning without oxygen to increase the amount of CO; 3) balancing on several gasification workplaces. Set fire to different gasification workplaces asynchronously to balance the reduction of the flammable components while the burning point is near the exit hole. The three methods are still used at present, but none of them can solve the gasification stability by nature, especially the danger of the death of burning without oxygen. So, to raise a new method of drilling holes to adjust and control it is a technical problem on gasification stability research.The controlling mechanism put forward in the study, the compensation mechanism of deoxidize zone based on the principle "suitable to march forward., reverse to spread", the deoxidize reaction of gasification mark gas and the principle of pyrolysis chain reaction are supplement to underground gasification theory and have theoretical guide values in raising the density, promoting the speed of reducing transformation and raising heat value.This thesis studies the essential features of the "three zones"and the carries onthe systematic analysis and research to the stability of the process of the underground gasification of coal. Studying the chemical balance,energy balance and material balance in the gasification process and probing into the interaction in the gasification process and law of changing offer a theoretical foundation for gasification control. Through the materialization nature of coal, the gasification characteristics of the deoxidize zone are mainly studied (the dynamics characteristics and chemical characteristics). Probing into coz deoxidize mechanism ?establishes the theoretical foundation for the proposition of mark gas;the Principle to adjust and control temperature and applying methods is studied;the physical and mathematical models of underground gasification are set up;A temperature field in the district of gasification is set up and the instance analysis of computer analogue simulation machine has been carried out.Give a new concept "mark gas" for the first time. With certain gasification method, one or two kind of gases near to the exit, which can uniquely mark the burning state of the gasification workplace, is called "mark gas". For instance, the mark gas of air gas is CO2 while the water gas considers H2 and CO as its mark gas. It can provide countable basis for adjusting and controlling.Mark gas is also a vital measure to inspect the gasification effects of the workplace. The inspecting machine that is placed near the exit can check out the amount of mark gas in the flammable gas, thus can verify the effects of gasification. For air gas, the amount of CO2 is the main part to be inspected as the basis of weather to adjust and control or not. For water gas, the inspection of the amount of H2 and CO is the basis.In the gasification reaction...