Heat Pipe Thermal Displacement for Coal Seam Gas Extraction
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Solution Overview
Problem
Current gas extraction methods in coal mines, such as hydraulic slotting and explosive fracturing, face challenges like water blocking, safety concerns, and inefficiency due to low air permeability in coal seams, necessitating a safer, more efficient, and cost-effective approach for enhancing permeability and preventing gas outbursts.
Innovation Solution
The method involves drilling staggered thermal displacement boreholes with heat pipes to create a high-temperature field around extraction boreholes, promoting gas desorption by increasing the temperature of the coal mass, thus enhancing gas extraction efficiency without the drawbacks of existing methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydraulic slotting or hydraulic fracturing is used to improve air permeability, then gas extraction effect is improved, but water blocking effect occurs which inhibits gas desorption
Solution Approach 1:
The patent replaces hydraulic mechanical systems (hydraulic slotting/fracturing) with a thermal field system. By injecting hot water or steam into the coal seam through boreholes, the coal mass is heated to increase its temperature, which promotes gas desorption and improves permeability without creating water blocking issues associated with hydraulic methods.
Solution Approach 2:
The patent changes the physical parameter of the coal mass from常温 (ambient temperature) to high temperature (heated by hot water or steam). This temperature parameter change fundamentally alters the gas adsorption characteristics of the coal, reducing gas adsorption capacity and promoting gas desorption, thereby improving gas extraction without water blocking.
2Productivity
If explosive explosion is used to fracture coal mass and improve air permeability, then gas extraction effect is improved, but it wastes time and energy and poses safety risks
Solution Approach 1:
The patent replaces the explosive mechanical system with a thermal field system. Instead of using explosives to fracture the coal mass, hot water or steam is injected to heat the coal, which naturally promotes gas desorption and improves permeability through thermal effects rather than violent mechanical disruption, thereby eliminating safety risks associated with explosives.
Solution Approach 2:
The patent converts the potentially harmful effect of high temperature (which could cause coal combustion or methane explosion) into a beneficial thermal field for gas desorption. By controlling the temperature through regulated injection of hot water or steam, the system safely utilizes thermal energy to promote gas release without creating the explosive conditions that would result from uncontrolled heating.
3Productivity
If explosive explosion is used to fracture coal mass, then air permeability is improved, but it wastes time and energy
Solution Approach 1:
The patent replaces the time-consuming explosive fracturing process with a more efficient thermal heating process. By injecting hot water or steam directly into the coal seam, the system rapidly establishes a thermal field that promotes immediate gas desorption and permeability improvement, eliminating the lengthy preparation and detonation sequences required for explosive methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method significantly improves gas extraction efficiency by 40% or more, is safe, reliable, cost-effective, and easy to implement, while reducing the risk of coal and gas outbursts, making it a practical solution for deep coal and gas extraction.
Implementation Method 1
starting the heating device, the heat pipe absorbing heat from the heating device and thereby releasing heat into the thermal displacement borehole continuously
Implementation Method 2
the heat pipe absorbing heat from the heating device and thereby releasing heat into the thermal displacement borehole continuously, so as to increase the temperature in the borehole and in the coal mass around the borehole
Implementation Method 3
starting the heating device, the heat pipe absorbing heat from the heating device and thereby releasing heat into the thermal displacement borehole continuously
Implementation Method 4
starting the grouting pump to inject grout into the thermal displacement borehole through the grouting pipe
Data Source
AI summary
A method for thermal-displacement-type strengthened extraction in a drill hole, suitable for efficient gas extraction in a coal mine, the method comprising the following steps: arranging an extraction drill hole and a thermal displacement drill hole at intervals in a coal seam; continuously heating coal in the drill hole to form a stable temperature field by using a heat pipe; and significantly reducing gas adsorption potential by utilizing a heat effect, prompting gas desorption, and strengthening gas extraction. The method enlarges a range of effective pressure relief influence of a single hole, increases an extraction efficiency of gas in a coal seam by more than 40%, is safe, reliable and low-cost, and is easy to operate, saving both time and labor.