Ducting system

A ducting system for conveying a flow of a gaseous feed of ventilation air derived from a coal mine comprising a combustible component from an inlet to at least one combustion module, the system comprising:

• a sensor to measure a concentration of the combustible component in the flow of the gaseous feed;
• a flame detector;
• a shut-off valve configurable to have an open position to allow the flow of the gaseous feed from the inlet to the at least one combustion module and a closed position to prevent the flow of the gaseous feed from the inlet to the at least one combustion module;
• and a flame arrestor located in a flow path of the gaseous feed upstream of the shut-oft valve, wherein the shut-off valve is operatively associated with the sensor such that a measurement of a concentration of the combustible component in flow of the gaseous feed over a specified concentration by the sensor causes the shut-off valve to be configured to the closed position for preventing flow of a gaseous feed comprising a combustible mixture of the combustible component from reaching an ignition source, wherein the specified concentration is 1.25% methane as the combustible component;
• and wherein the shut-off valve is operatively associated with the flame detector such that detection of flame by the flame detector causes the shut-off valve to be configured to the closed position for attenuating propagation of a flame toward the inlet;
• further comprising a supplementary gaseous feed comprising a supplementary combustible component and a supplementary gaseous feed valve for controlling flow of supplementary gaseous feed into the flow of the gaseous feed downstream of the shut-off valve, wherein the supplementary gaseous feed is in fluid communication with a gas mixer for mixing the gaseous feed with the supplementary gaseous feed.

A ducting system for conveying a flow of a gaseous feed of ventilation air derived from a coal mine comprising a combustible component from an inlet to at least one combustion module, the system comprising:

• a shut-off valve configurable to have an open position to allow the flow of the gaseous feed from the inlet to the at least one combustion module and a closed position to prevent the flow of the gaseous feed from the inlet to the at least one combustion module;
• a sensor to measure a concentration of the combustible component in the flow of the gaseous feed, the sensor located upstream of the shut-off valve;
• a flame detector located downstream of the shut-off valve;
• a flame arrestor located in a flow path of the gaseous feed upstream of the shut-off valve;
• a source of fire retardant and a fire retardant valve feeding one or more fire retardant injection points for controlling flow of the fire retardant into the ducting system, the one or more fire retardant injection points positioned between the flame arrestor and the at least one combustion module;
• a supplementary gaseous feed in fluid communication with a gas mixer for mixing the gaseous feed with the supplementary gaseous feed, the supplementary gaseous feed comprising a supplementary combustible component;
• a supplementary gaseous feed valve for controlling flow of supplementary gaseous feed into the flow of the gaseous feed downstream of the shut-off valve;
• a source of fresh air and a fresh air valve for controlling flow of the source of fresh air into the flow of the gaseous feed at a position upstream of the mixer;
• and
• a pair of supplementary sensors to measure a concentration of the combustible component in the flow of the gaseous feed, wherein the pair of supplementary sensors comprise one supplementary sensor positioned upstream of the mixer and another supplementary sensor positioned downstream of the mixer,
• wherein the shut-off valve is operatively associated with the sensor such that a measurement of a concentration of the combustible component in flow of the gaseous feed over a specified concentration by the sensor causes the shut-off valve to be configured to the closed position for preventing flow of a gaseous feed comprising a combustible mixture of the combustible component from reaching an ignition source, wherein the specified concentration is 1.25% methane as the combustible component,
• wherein the shut-off valve is operatively associated with the flame detector such that detection of flame by the flame detector causes the shut-off valve to be configured to the closed position for attenuating propagation of a flame toward the inlet,
• wherein the fire retardant valve is operatively associated with the flame detector such that detection of flame by the flame detector causes the fire retardant valve to open allowing the fire retardant to flow into the ducting system for attenuating the detected flame, and
• wherein the pair of supplementary sensors are operatively associated with the second fresh air valve and the supplementary gaseous feed valve for controlling the concentration of the combustible component in the flow of the gaseous feed leaving the mixer.