煤矿采空区液态CO2灌注防灭火关键参数研究

1.教育部 西部矿井开采与灾害防治重点实验室,陕西 西安 710054; 2.西安科技大学 安全科学与工程学院,陕西 西安 710054; 3.西安科技大学 能源学院,陕西 西安 710054

液态CO2; 采空区; 结冰; 灌注量; 气化吸热量

Key parameters of liquid CO2 perfusion for fire control in coal mine goaf
DENG Jun1,2,XI Hong-jun1,3,ZHAI Xiao-wei1,2,ZHANG Yan-ni1,2

(1.Key Laboratory of Western Mine Exploration and Hazard Prevention,Ministry of Education,Xi'an 710054,China; 2.College of Safety Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China; 3.College of Energy Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China)

liquid carbon dioxide; goaf; freeze; perfusion quantity; vaporization heat

DOI: 10.13800/j.cnki.xakjdxxb.2017.0501

备注

液态CO2用于防治煤矿采空区火灾,相比传统的注氮防灭火有诸多优势,是一种有较好发展前景的采空区防灭火方法,为解决其在气化过程中易结冰及爆震,灌注量难于计算,气化吸热量较难确定这几个关键问题,对液态CO2物性参数及其相变规律作了深入分析,结果表明:液态CO2气化过程中易结冰的主要原因是其三相点温度(-56. 6 ℃)较高,压力快速降低时气化导致的大量吸热使其温度达到三相点从而结冰,故防结冰首要措施是布设旁路气化增压系统及气相均压连通系统,并保持压力在1.2 MPa以上; 防灭火灌注量需要控制采空区氧浓度为3%~5%以下,并参照液氮灌注防灭火计算方法求出灌注量; 液态CO2气化潜热跟其压力(温度)关系密切且变化较大,在考虑其对采空区的降温效果时应严格以压力(温度)为基准计算它的气化吸热量。通过这些研究为液态CO2采空区灌注防灭火这一新技术的可靠应用及量化计算提供了一种新的解决方案。

For fire prevention and extinguishment in coal mine goaf,liquid carbon dioxide has many advantages when compared with the traditional liquid nitrogen perfusion for fire control system,thus it has a good developmental prospects for fire prevention and extinguishment in coal mine goaf.For research of some key problems in its promotion and application which includethe gasification process is easy to be freezed and knocked,the perfusion volume is difficult to calculate,the heat absorption of gasification is difficult to determine,we use methods of indepth analysis for the physical parameters andlaw of phase transtition for liquid CO2,the results shows as follows:liquid CO2 is easily to be freezed in gasification process, this mainly attributes to it has a higher triple point temperature(-56. 6 ℃),when a sudden pressure declination happens, liquid carbon dioxide will gasify quickly,a lot of heat would be absorbed from liquid carbon dioxide which may causes its temperature decline to the triple point,so the first impormant step for anti-freezing in transportation and gasification is to layout bypass gasification pressurization system and uniform gas pressure connecting system,meanwhile keep its pressure above 1.2 MPa,the fire extinguishing perfusion volume have to control oxygen density below to 3%~5% and can be obtained according to liquid nitrogen perfusion system; the heat absorption of liquid CO2 is closely relate to its pressure(temperature)and varies greatly,it should be strict accorded to its pressure(temperature)when considering the effect for cooling goaf. These researches provide a new solution for the reliable application and quantitative calculation of the new technology.