Ultrasonic Nitrogen Pressurization for Low-Gas Coal Seam Extraction
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Solution Overview
Problem
The high-intensity mining process in low-gas mines leads to a sharp increase in gas concentration, posing safety risks and inefficiencies due to low initial gas content and pressure, and existing permeability enhancement methods like hydrofracturing and presplit blasting are ineffective or environmentally harmful.
Innovation Solution
An ultrasonic excitation and nitrogen-injection pressurization coupling method is employed, using an integrated device with ultrasonic transducers and nitrogen injection to enhance coal seam permeability and gas flow driving force, involving boreholes and controlled gas extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If hydrofracturing technique is used to enhance permeability, then permeability of coal seams is improved, but water consumption increases and environmental pollution occurs
Solution Approach 1:
The patent replaces the hydrofracturing mechanical system with an ultrasonic excitation system. The ultrasonic device uses high-frequency mechanical vibrations to induce micro-fractures and enhance permeability without requiring large quantities of water, thereby eliminating the water consumption and pollution problems associated with traditional hydrofracturing while achieving the same permeability enhancement goal.
Solution Approach 2:
The patent changes the physical parameters of the permeability enhancement process by using ultrasonic frequency vibrations instead of hydraulic pressure. This parameter change allows for permeability enhancement through controlled micro-fracturing caused by ultrasonic resonance, avoiding the need for water injection and subsequent environmental management.
2Stability of the object's composition
If presplit blasting technique is used to enhance permeability, then permeability of hard coal seams is improved, but secondary disasters may be induced in soft coal seams
Solution Approach 1:
The patent replaces the explosive mechanical system with an ultrasonic excitation system. The ultrasonic device delivers controlled mechanical vibrations that gradually enhance permeability through micro-fracture propagation, eliminating the risk of sudden, uncontrolled blasting events that can cause secondary disasters, while still achieving effective permeability enhancement in both hard and soft coal seams.
Solution Approach 2:
The patent introduces a dynamic, controllable permeability enhancement process where ultrasonic parameters (frequency, power, duration) can be adjusted in real-time based on coal seam conditions. This dynamic approach allows for safe and effective treatment of varying coal types without the fixed, high-risk nature of blasting operations.
3Object-affected harmful factors
If ventilation system is used to blow gas during high-intensity mining, then gas concentration is reduced, but production coordination is affected and atmospheric pollution increases
Solution Approach 1:
The patent applies preliminary permeability enhancement through ultrasonic excitation before gas extraction begins. By pre-enhancing the permeability of the coal seam, the system creates more effective flow channels that enable faster and more efficient gas removal during mining, reducing the need for ventilation interruptions and maintaining better production coordination.
Solution Approach 2:
The patent introduces an intermediary permeability enhancement step between gas accumulation and extraction. The ultrasonic treatment acts as a mediator that prepares the coal seam structure to facilitate more efficient gas flow, thereby improving the overall coordination of the gas management system and reducing the need for disruptive ventilation operations.
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 effectively increases permeability and gas flow driving force, enhancing gas extraction efficiency by promoting fracture formation and desorption, thereby improving safety and productivity in low-gas mines.
Implementation Method 1
ultrasonic excitation... ultrasonic transducer... ultrasonic excitation can effectively improve the pore structure of coal seams, enhance pore connectivity and promote desorption of adsorbed gas
Implementation Method 2
nitrogen-injection pressurization... increase the gas flow driving force in the coal seams to promote gas flow
Implementation Method 3
ultrasonic excitation... promote desorption of adsorbed gas in the coal seams
Data Source
AI summary
The invention discloses an ultrasonic excitation and nitrogen-injection pressurization coupling-enhanced gas extraction device and method for a low-gas coal seam. The ultrasonic excitation and nitrogen-injection pressurization coupling-enhanced gas extraction device includes a permeability-enhancement borehole and at least two exploration boreholes. An extraction sieve tube is mounted in each of the boreholes. An ultrasonic excitation and nitrogen-injection pressurization coupling integrated device is mounted in the extraction sieve tube in the permeability-enhancement borehole. The invention increases the permeability of coal seams and the gas flow driving force of the coal seams, thus efficiently solving the problem of a failure of gas extraction from low-gas coal seams.