Gas supply system for a gas engine or dual-fuel engine and method for operating the same

A method for operating a gas supply system for an engine having cylinders that is designed as a gas engine or a dual fuel engine having:

• supplying, via a gas regulating station the engine in a gas fuel operating mode with a gaseous fuel of constant gas pressure as a function of a requested engine output;
• coupling the gas regulating station to the cylinders via a double-walled gas line the double-walled gas line comprises:
• an inner pipe having an uninterrupted surface with outlets only at its axial ends;
• an outer pipe having an unobstructed interior space defined by an outer surface of the inner pipe and an inner surface of the outer pipe, which surrounds the inner pipe at least in sections so that the inner pipe is separated from the outer pipe;
• and
• a check valve, only in the inner pipe, provided at the engine-side end radially within the double-walled gas line that is configured to provide a flow towards at least one vent line,
• wherein in the gas fuel operating mode of the double-walled gas line, emanating from a gas regulating station-side end of the double-walled gas line:
• flowing the gaseous fuel through the outer pipe in the direction of an engine-side end of the double-walled gas line,
• an inert gas purging line;
• a first shut-off valve connected to the inert gas purging line,
• wherein in a purging mode of the engine:
• with
• opening the first shut-off valve in an opened state,
• feeding inert gas via the inert gas purging line to the outer pipe of the double-walled gas line at the gas regulating station-side end of the double-walled gas line,
• flowing the inert gas through the outer pipe towards an engine-side end of the double-walled gas line, where the inert gas passes into the inner pipe and, via the inner pipe, flows back towards the gas regulating station-side end of the double-walled gas line where the inert gas then exits;
• the outer pipe of the double-walled gas line in the gas fuel operating mode of the engine can be flowed through by purging in the direction of the gas regulating station for discharging a gas leakage,
• the gas supply system further comprising:
• feeding via a purge air supply line, purge air to the outer pipe at the engine-side end of the double-walled gas line;
• discharging via a purge air discharge line, purge air from the outer pipe at the gas regulating station-side end of the double-walled gas line;
• a second shut-off valve assigned to the purge air supply line;
• and
• a third shut-off valve assigned to the purge air discharge line,
• closing the first shut-off valve is closed and opening the second and third shut-off valve wherein gaseous fuel is combusted in the engine in the gas fuel operating mode.