Device for preventing steam from being produced in flue gas cooler for oxyfuel combustion boiler

A device for preventing steam from being produced in an flue gas cooler for an oxyfuel combustion boiler with a boiler low-pressure feed-water system comprising a condenser, a condensate pump, a low-pressure feed-water heater and a boiler feed-water pump in the order named and wherein, in oxyfuel combustion, part of the low-pressure feed-water boosted in pressure by the condensate pump in the boiler low-pressure feed-water system is sent under pressure by a booster pump to the flue gas cooler where the low-pressure feed-water heat exchanged with flue gas is guided again to the boiler low-pressure feed-water system, comprising

• a bypass line for connecting a feed-water discharge side of the condenser with a feed-water entry side of the flue gas cooler by bypassing the condensate and booster pumps,
• a steam production preventive pump in the bypass line,
• an inlet cutoff valve in the bypass line,
• a steam production preventive water circulation line for connecting a feed-water discharge side of the flue gas cooler with a feed-water entry side of the condenser and
• an outlet cutoff valve in the steam production preventive water circulation line,
• when the boiler feed-water pump stops in boiler fuel cutoff, the inlet and outlet cutoff valves being opened and the steam production preventive pump being activated to cause water to flows through the bypass line to the flue gas cooler and return and circulate through the steam production preventive water circulation line to the condenser.