Design And Research The Test System Aimed At The Liquid Carbon Dioxide Blast Pre-splitting In Low Permeability Coal Seam

The coal resources in our country are abundant, among which most of them belong to low permeability coal seam. The gas that is adsorbed in the coals would gradually resolve and float into the air during the process of coal mining, and the gas disaster will happen if the gas density in air increases to a certain amount. In order to prevent the gas disaster, artificially increasing the permeability of the coal seam is the most effective measure. Liquid carbon dioxide blast pre-splitting is a new sort of coal anti-reflection technology which has the characteristics of efficient and safe. As pressure and temperature are the key parameters to evaluate the anti-reflection effect in the process of blast pre-splitting, where the coal steam environment is complicated, it is absolutely essential to design and research the test system aimed at the liquid carbon dioxide blast pre-splitting in low permeability coal seam.This article carried out the design and research of test system with the technology route of theoretical research, system design and field trial. The main contents are as follows:Firstly, the low permeability coal steam liquid carbon dioxide blast pre-splitting is taken as the research object. Then, to introduce the work principles of the blast pre-splitting and analyses the features of the test environment. In the meanwhile, the dynamic storage testing technology is used as the theoretical guidance to describe the design principles of the test system.Secondly, the overall design of work principles, signal properties and logical states are conducted based on the tasks and the requirements of the test. Moreover, the key technologies such as sampling strategy, intelligent trigger and negative delay, and the buffer protection of the test system are researched as well.Next, in the test system, taking the overall design as the guidance, the analog circuit of sensor selection, adaptation amplifying circuit and power management circuits and digital circuit of the hardware design, and the design principles and design processes of each circuit module are described in details. At the same time, the operations and functions of the system of communication interface and specific software are explained.Lastly, different amount of liquid carbon dioxide are injected in the simulation in order to obtain the measured data, and the technical characteristics of the blast pre-splitting are summarized. Furthermore, based on the typical pressure change of the working procedure, the action mechanisms of the coal steam fracture are researched。...