气化采煤中气化炉温度场获取壤中氡方法研究

Our country is rich in resources of coal. It is the correct choice to coordinate and solve the coal utilization and environmental problems by gasification mining. Since it has no effective method, the main bottleneck problem in current commercial gasification mining is the production of combustible gas concentration, composition and calorific value is not stable. In order to solve this problem effectively we should monitor underground coal bed combustion state to control the combustion process. The underground temperature field is the key information which is most direct reaction combustion state. But it is difficult to measure the temperature field directly.In coal gasification process, the combustion temperature will accelerate radon exhalation and provide favorable condition for radon migration towards the earth surface. It has been proved that the top of combustion furnace has obvious soil radon anomaly by experiments. But because of the soil radon measurement method, it still needs further research to indicate the target of underground coal bed combustion state using soil radon measurement results to determine the temperature field of underground. In this research we will measure the soil radon content in coal gasification process using the soil radon measurement system which has multi point array type network and measure the soil radon in synchronous accumulation and real time with multi parameters. We can obtain the characteristic quantity of multi parameter using the method such as wavelet analysis, correlation analysis, feature tree search, nonlinear quantization preprocessing and principal component analysis. Then we can get the underground coal bed temperature by using the neural network method. And then contrast its correctness which is measured by the thermocouple installed in the coal bed. Then through wavelet analysis and finite difference algorithm for extracting temperature anomaly information, thus delineating underground combustion area, and then to explore related laws of the surface soil radon anomaly and underground coal gasification state, to provide effective technical method and scientific basis for coal mining.

气化采煤是协调解决煤利用率和环境问题的首选。目前商业性气化采煤遇到的主要瓶颈是生产的可燃气体的浓度、组分和热值不稳定。为解决这一问题需有效监控地下煤层燃烧状态来控制燃烧过程，而地下温度场是最直接反应燃烧状态的关键信息，但直接测量温度场又存在难度。煤在气化时的燃烧温度会加速地层中氡的析出，并为氡向地表迁移提供有利条件。实验证明燃烧炉上方有明显的壤氡异常，可通过一种有效壤氡测量方法获取这一异常信息从而可间接研究煤层燃烧状态的目的。本项目通过多点阵列式组网同步累积壤氡多参数实时测量煤气化进程中的壤氡浓度，先由小波分析、特征树搜索、非线性量化预处理及主成分相关分析等算法提取壤氡多参数特征量，再由神经网络方法获取地下煤层温度，并与热电偶的实测值对比其正确性；最后由小波分析提取温度场特征信息，从而圈定地下燃烧区，进而探索地表壤氡异常与地下煤气化状态关系的相关规律，为煤气化开采提供有效的技术和科学依据。

气化采煤是协调解决煤利用率和环境问题的首选。目前商业性气化采煤遇到的主要瓶颈是生产的可燃气体的浓度、组分和热值不稳定。为解决这一问题需有效监控地下煤层燃烧状态来控制燃烧过程，而地下温度场是最直接反应燃烧状态的关键信息，但直接测量温度场又存在难度。煤在气化时的燃烧温度会加速地层中氡的析出，并为氡向地表迁移提供有利条件。实验证明燃烧炉上方有明显的壤氡异常，可通过一种有效壤氡测量方法获取这一异常信息从而间接深入研究煤层燃烧状态的目的。.项目主要研究内容为：.1..研究应用于煤气化进程中地表壤氡α能谱阵列式多测点同步实时连续累积测量的实验系统，寻找更为快速有效、适合跟踪气化进程的测氡方法。.2..壤氡异常信息提取方法研究，研究地面测氡数据处理分析方法，研究测氡异常和背景值的确定原则。.3..研究壤氡α能谱测量异常与地下气化的关系，研究氡α能谱测量异常与地下温度的关系，研究建立气化采煤进程中地表氡气异常变化规律。.自从本项目批准后，课题组通过近10个月的努力，完成了实验系统的研制和调试工作，并与2013年5月在内蒙古乌兰察布进行地表壤氡测量的实验系统的安装调试，实验系统从2013年5月15日正式开始土壤氡浓度测量。实验系统一共有21台测氡仪和1台气象采集仪组成，20台测氡仪分布在气化采煤通道的上方，另一台测氡仪放置在较远的地方测量本底的变化规律，气象采集仪可以实现对空气温度、空气湿度、风速等的精确测量。气化采煤通道在5月30日开始加压，7月12日通道被压通，正式开始点火，经过测量已经取得一批实测数据，通过对实验数据的分析，以及热电偶的监测数据，可以清晰的看出地下地下燃烧炉火区的变化。为圈定地下燃烧区，进而探索地表壤氡异常与地下煤气化状态关系的相关规律，为煤气化开采提供有效的技术方法和科学依据。