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CN-122014353-A - Liquid CO for goaf2Rapid calculation method for inerting range

CN122014353ACN 122014353 ACN122014353 ACN 122014353ACN-122014353-A

Abstract

The invention discloses a rapid calculation method for an inerting range of liquid CO 2 in a goaf, which comprises the following steps of S1, constructing a liquid CO 2 goaf cooling system, S2, calculating a goaf air flow field by taking the middle part of a working surface as an origin, S3, calculating the average temperature of an oxidation temperature rising zone of the goaf, S4, calculating the gas diffusion range of pressure injection CO 2 in the goaf, and S5, stopping pressure injection of the CO 2 cooling system to obtain the influence range of single pressure injection liquid CO 2 on the goaf. The rapid calculation method for the inerting range of the liquid CO 2 in the goaf solves the problem of poor fire prevention and extinguishing effects caused by inaccurate prediction of the diffusion range of the liquid CO 2 in the goaf.

Inventors

  • REN LIFENG
  • SHI JIANXUN
  • Hao le
  • MA TENG
  • TAO FAN
  • CHONG JIE
  • SHI XINYI

Assignees

  • 西安科技大学

Dates

Publication Date
20260512
Application Date
20260401

Claims (10)

  1. 1. The rapid calculation method for the inerting range of the goaf liquid CO 2 is characterized by comprising the following steps of: S1, constructing a liquid CO 2 goaf cooling system; s2, calculating a goaf air flow field by taking the middle of the working surface as an origin; s3, calculating the average temperature of an oxidation temperature rise zone of the goaf; s4, calculating the gas diffusion range of the injection CO 2 in the goaf; S5, stopping pressure injection of the CO 2 cooling system, and obtaining the influence range of single pressure injection liquid CO 2 on the goaf.
  2. 2. The rapid calculation method for the goaf liquid CO 2 inerting range according to claim 1, wherein the liquid CO 2 goaf cooling system comprises a liquid CO 2 goaf pressure injection pipeline (4), a temperature sensor (10) and an air speed sensor (11), wherein an outlet of the liquid CO 2 goaf pressure injection pipeline (4) is arranged on one side of a goaf oxidation temperature rise zone close to a coal pillar, the air speed sensor (11) is arranged on an air inlet roadway and an air return roadway, and the temperature sensor (10) is arranged at the positions of upper corners, lower corners and liquid CO 2 pressure injection ports; The wind speed sensor (11) is an intrinsic safety type wind speed sensor, the wind speed sensor (11) is arranged on two sides of an air inlet lane (6) and an air return lane (8) close to a coal pillar, the wind speed sensor (11) is arranged at a position which is vertical to a bottom plate 2m high and is 50m away from upper and lower corners, the wind speed sensor (11) is used for measuring the wind speed V 1 、V 2 of the air inlet lane (6) and the air return lane (8), the wind speed sensor (11) is connected with an on-well centralized processor through a wire, and the wind speed sensor (11) transmits signals to the on-well centralized processor through the wire to perform calculation and data storage.
  3. 3. The rapid calculation method for the goaf liquid state CO 2 inerting range according to claim 1, wherein the temperature sensor (10) is an intrinsic safety type temperature sensor, the temperature sensor (10) is respectively arranged on a top plate at an upper corner and a lower corner in a hanging mode, the temperature sensor (10) is respectively used for detecting real-time temperature data T j 、T h 、T g at the upper corner, the lower corner and a liquid state CO 2 injection port position, the temperature sensor (10) is connected with an on-well centralized processor through a wire, and the temperature sensor (10) transmits signals to the on-well centralized processor through the wire for calculation and data storage.
  4. 4. The method for rapidly calculating the inerting range of the goaf liquid CO 2 according to claim 1, wherein S2 is specifically: S2.1, acquiring information of a heat dissipation belt and an oxidation heat rising belt in a goaf; Defining the furthest distance of one side of a cooling belt air inlet lane as H ji , namely the closest distance of the air inlet side of an oxidation heating belt as H ji , and the furthest distance of one side of a cooling belt air return lane as H hi , namely the closest distance of the air inlet side of the oxidation heating belt as H hi , wherein the furthest distance of the air inlet side of the oxidation heating belt as H jm and the furthest distance of the air return side of the oxidation heating belt as H hm ; S2.2, calculating an air flow path in the goaf by taking the middle of the working surface as an origin; The goaf is divided into a heat radiation belt and an oxidation temperature rise belt due to the influence of wind flow of the goaf, a lower corner is an air inlet, an upper corner is an air outlet, a wind flow path is approximately elliptical, and a working face support is a symmetrical dividing line of the ellipse to calculate the wind flow path in the goaf; S2.3, acquiring wind speed information at the positions of an air inlet roadway and an air return roadway; S2.4, calculating the migration time of the wind flow into the goaf through a formula (1) according to the wind flow path and the wind speed information; (1); Wherein t is the migration time of underground wind flow entering the goaf, M s1 is the migration distance of wind flow entering the heat dissipation belt for the first time and not entering the oxidation heat rising belt, M y is the migration distance of wind flow in the oxidation heat rising belt, and M s2 is the migration distance of wind flow entering the heat dissipation belt again after leaving the oxidation heat rising belt; s2.5, calculating to obtain a goaf wind flow field through a formula (2) according to the wind flow path, wind speed information and migration time; (2); where a is a dimensionless constant of the wind flow path, and is set at the furthest distance in the x-axis from the calculated wind flow elliptical path.
  5. 5. The method for rapidly calculating the inerting range of the goaf liquid CO 2 according to claim 1, wherein S3 is specifically: S3.1, obtaining temperature information at the position of the upper corner and the lower corner; S3.2, calculating to obtain total heating quantity of air caused by coal in the goaf according to the wind speed information and the temperature information through a formula (3); (3); Wherein T c is total heat dissipation, namely heat generated by oxidization heating zone of goaf, S j is average tunnel section size of air inlet tunnel, m 2 ;S h is average tunnel section size of air return tunnel, m 2 , 1.2 is average density of tunnel gas, kg/m 3 , 1005 is specific heat capacity of air, J/(kg) K); S3.3, calculating the total heat dissipation amount of the goaf residual coal oxidation heat rise zone; The total heat dissipation amount of the goaf coal-missing oxidation heat-up zone consists of a heat dissipation zone of the goaf and coal-missing oxidation heat-up zone, the heat accumulation of the heat dissipation zone coal-missing is difficult due to the influence of wind speed, and the coal-missing oxidation reaction is mainly concentrated in the oxidation heat-up zone, so that the total heat of air temperature rise caused by coal-missing is equal to the total heat dissipation amount of the coal-missing oxidation heat-up zone; S3.4, calculating the goaf oxidation temperature rise zone coal-losing temperature according to formulas (4), (5) and (6); (4); (5); (6); wherein S yy is the estimated oxidation-heating zone coal surface area of the goaf, m 2 , alpha is the convective heat transfer coefficient, W/(m) 2 K) The temperature is obtained through experimental means or is brought into an empirical constant of 14.7, and T ym is the coal-losing temperature in the oxidation temperature-rising zone of the goaf, K.
  6. 6. The method for rapidly calculating the inerting range of the goaf liquid CO 2 according to claim 1, wherein S4 is specifically: S4.1, acquiring pressure injection information of a liquid CO 2 pipeline, wherein the pressure injection information comprises pipeline pressure, pipeline diameter and pressure injection duration; S4.2, inputting the goaf air flow field obtained in the step S2.5, the goaf oxidation temperature rise zone coal-losing temperature obtained in the step S3.4 and the liquid CO 2 injection information obtained in the step S4.1 into a CO 2 injection range coupling model; S4.3, obtaining the influence range of the CO 2 under different injection times.
  7. 7. The method according to claim 4, wherein S2.2 is the air flow path in the goaf, the middle of the bracket is used as an origin (0, 0), the working surface length is H, the lower corner coordinates are (0, H/2), and the upper corner coordinates are (0, -H/2).
  8. 8. The method for rapidly calculating the inerting range of the goaf liquid CO 2 according to claim 4, wherein the migration time in S2.4 is composed of two sections of heat dissipation zone migration time and oxidation heating zone migration time of wind flow in the goaf, the gas migration speed in the heat dissipation zone is the gas migration speed of an air inlet or an air return channel close to one side, and the gas migration speed in the oxidation heat dissipation zone is fixed to be 0.2m/min.
  9. 9. The method for rapidly calculating the inerting range of liquid CO 2 in a goaf according to claim 6, wherein the CO 2 injection range coupling model in S4.2 is specifically: S4.2.1, constructing a goaf liquid CO 2 injection molding model by CFD simulation software, wherein the injection molding model is used for simulating the goaf CO 2 gas diffusion range under different injection conditions; S4.2.2, calculating the farthest distances (x 20 ,y 20 ）、（x 5 ,y 5 ）、（x 1 ,y 1 ) from the CO 2 gas diffusion to three key thresholds under different initial conditions by using the goaf CO 2 concentration as 1%, 5% and 20% as thresholds through a pressure injection model, and obtaining an experimental dataset of the farthest distances under different pressure injection conditions; S4.2.3, using the Gaussian mass model as a baseline model, optimizing the diffusion coefficient in the original model through an experimental data set, and optimizing the Gaussian mass model; S4.2.4, obtaining an optimized pressure injection range coupling model.
  10. 10. The rapid calculation method for the inerting range of the goaf liquid CO 2 , which is characterized in that the diffusion coefficient in the optimized original model in S4.2.3 is specifically calculated according to formulas (7) - (11); (7); (8); (9); (10); (11); Wherein, C (x, y) is the concentration of CO 2 gas at the space position (x, y), kg/M 3 , Q is the pressure injection rate, kg/s, u is the ambient wind speed, M/s, sigma x 、σ y 、σ z is the diffusion coefficient of the horizontal vertical direction, the horizontal transverse direction and the vertical direction respectively, namely the diffusion coefficient of the downwind direction, the side wind direction and the vertical wind direction, M, R is the radius of the pressure injection pipeline, M, P is the pressure in the pipe, pa, M is the relative molecular mass of the pressure injection gas, R is the pressure injection gas constant, lambda is the gas heat insulation coefficient, y 'is the tangent of the wind flow of the goaf under the jurisdiction, theta is the angle of the wind flow relative to the origin, K is the optimized diffusion coefficient, (x 0 ,y 0 ) is the position of the pressure injection CO 2 port, C' (20%), C '(5%) and C' (1%) are the inverse functions of the gas formula (1) under the concentrations of 20%, 5% and 1% CO 2 respectively, namely the corresponding coordinate positions.

Description

Rapid calculation method for inerting range of goaf liquid CO 2 Technical Field The invention belongs to the technical field of goaf fire prevention and extinguishment, and particularly relates to a rapid calculation method for a goaf liquid CO 2 inerting range. Background The problem of oxidization heating in the goaf of the coal mine is an important hidden trouble threatening the safety of the coal mine, and spontaneous combustion of the coal is extremely easy to occur in a high-temperature environment. The traditional prediction method mainly depends on a physical model and an empirical formula, but has obviously insufficient accuracy and reliability under complex geological and wind flow conditions. The liquid CO 2 inerting technology has the advantages of rapid cooling, wide inerting range and the like, and becomes a common means in the field of coal mine fire prevention and extinguishment. However, when the method is applied, the prior art lacks an accurate calculation model for goaf wind flow field distribution and gas diffusion range, so that the inerting effect is difficult to dynamically predict. Therefore, the method capable of rapidly and accurately calculating the inerting range of the liquid CO 2 in the goaf is developed, and has urgent practical significance for improving the accuracy of spontaneous combustion disaster prediction and the emergency response efficiency of the coal mine. The main problem of the prior art is that the air flow field and the temperature distribution in the goaf cannot be accurately simulated, which makes the inerting range of the CO 2 difficult to determine. The migration of the goaf air flow field determines the CO 2 diffusion effect. The early warning and control system can only control the moment and the injection amount of the injected inert gas, and the diffusion condition after the inert gas is injected is not considered. The inert gas can be diffused along with the air flow field after being injected, the prediction method of the air flow field of the goaf according to an empirical formula and a traditional single model is mechanical, and the accuracy is low, so that the fire prevention and extinguishing effect of the inert gas on an oxidation zone is not directly influenced. Firstly, based on a fixed parameter hypothesis model, the dynamic change of the goaf environment cannot be responded quickly, and the timeliness requirement of fire prevention and extinguishment is difficult to meet. Secondly, the coupling modeling of the airflow field, the temperature field and the CO 2 diffusion process is lacked, the inerting effect under different pressure injection conditions cannot be accurately estimated, and CO 2 resource waste or full fire prevention and extinguishment are easily caused. Aiming at the problems, a rapid calculation method capable of dynamically coupling the wind flow, the temperature and the CO 2 diffusion characteristics of the goaf is provided, so that the accurate prediction of the inerting range of the liquid CO 2 is realized, and the fire prevention and extinguishing efficiency and the safety of the coal mine are improved. Disclosure of Invention The invention aims to provide a rapid calculation method for the inerting range of liquid CO 2 in a goaf, and solves the problem of poor fire prevention and extinguishing effects caused by inaccurate prediction of the diffusion range of liquid CO 2 in the goaf. The technical scheme adopted by the invention is that the rapid calculation method for the inerting range of the liquid CO 2 in the goaf comprises the following steps: S1, constructing a liquid CO 2 goaf cooling system; s2, calculating a goaf air flow field by taking the middle of the working surface as an origin; s3, calculating the average temperature of an oxidation temperature rise zone of the goaf; s4, calculating the gas diffusion range of the injection CO 2 in the goaf; S5, stopping pressure injection of the CO 2 cooling system, and obtaining the influence range of single pressure injection liquid CO 2 on the goaf. The invention is also characterized in that: The liquid CO 2 goaf cooling system comprises a liquid CO 2 goaf injection pipeline, a temperature sensor and a wind speed sensor, wherein an outlet of the liquid CO 2 goaf injection pipeline is arranged at one side of an oxidation temperature rising zone of the goaf close to a coal pillar; The wind speed sensor is an intrinsic safety type wind speed sensor, the wind speed sensor is arranged on two sides of the air inlet lane and the air return lane, which are close to the coal pillar, the wind speed sensor is arranged at the position which is 2m high and 50m away from the upper corner and the lower corner of the vertical bottom plate, the wind speed sensor is used for measuring the wind speed V 1、V2 of the air inlet lane and the air return lane, the wind speed sensor is connected with the centralized processor on the well through a wire, and the wind speed sensor transmits signa