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

Patent metadata

Field	Value
Publication number	US-2016169504-A1
Application number	US-201615053014-A
Country	US
Kind code	A1
Filing date	Feb 25, 2016
Priority date	Sep 18, 2013
Publication date	Jun 16, 2016
Grant date	—

Abstract

A feed-water discharge side of a condenser is connected to a feed-water entry side of an flue gas cooler through a bypass line provided with a steam production preventive pump and with an inlet cutoff valve. A feed-water discharge side of the flue gas cooler is connected to the feed-water entry side of the condenser through a steam production preventive water circulation line provided with an outlet cutoff valve. When a boiler feed-water pump is stopped in boiler fuel cutoff, the inlet and outlet cutoff valves are opened and the steam production preventive pump is activated to cause water to flow through the bypass line into the flue gas cooler, is returned through the steam production preventive water circulation line to the condenser and is circulated.

First claim

1 . 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.

2 . The device for preventing steam from being produced in the flue gas cooler for the oxyfuel combustion boiler as claimed in claim 1 , further comprising
a gas temperature gauge for measuring an inlet gas temperature of the flue gas cooler, a feed-water pressure gauge for measuring an outlet feed-water pressure of the flue gas cooler and a controller for outputting opening signals to the inlet and outlet cutoff valves, respectively, and a start signal to the steam production preventive pump when the inlet gas temperature measured by the gas temperature gauge exceeds an outlet feed-water saturation temperature based on the outlet feed-water pressure measured by the feed-water pressure gauge and a boiler fuel cutoff signal is inputted.

3 . The device for preventing steam from being produced in the flue gas cooler for the oxyfuel combustion boiler as claimed in claim 2 , further comprising a feed-water temperature gauge for measuring an outlet feed-water temperature of the flue gas cooler,
the controller being adapted to output the opening signals to the inlet and outlet cutoff valves, respectively, and the start signal to the steam production preventive pump when the outlet feed-water temperature measured by the feed-water temperature gauge exceeds the outlet feed-water saturation temperature based on the outlet feed-water pressure measured by the feed-water pressure gauge.

Assignees

• Ihi Corp

Inventors

• Uchida Terutoshi

Classifications

• F22D1/12 Primary

  Control devices, e.g. for regulating steam temperature · CPC title

• F23B5/02

  in main combustion chamber · CPC title

• F22D1/14

  Safety or venting devices · CPC title

• F23L7/007

  Supplying oxygen or oxygen-enriched air · CPC title

• F01K13/02

  Controlling, e.g. stopping or starting · CPC title