Condensate water and demineralized water indirect heat-exchange exhaust steam recovery two-stage deoxygenization device

Abstract

The invention relates to a condensate water and demineralized water indirect heat-exchange exhaust steam recovery two-stage deoxygenization device. According to the invention, a pressure-bearing buffering tank is provided with a first water inlet pipe and a third water inlet pipe positioned on an upper level, and a second water inlet pipe and a fourth water inlet pipe positioned on a lower level. Mixed condensate water is respectively subjected to indirect heat-exchange with synthetic ammonia demineralized water and transformation demineralized water through a third heat exchanger and a fourth heat exchanger, and is then respectively connected into the second water inlet pipe and the fourth water inlet pipe. After the heat-exchange process through the third and fourth heat exchangers, the synthetic demineralized water and the transformation demineralized water are respectively connected into the first water inlet pipe and the third water inlet pipe. Buffering tank exhaust steam enters a first heat exchanger and is cooled into buffering tank exhaust steam condensate water, and the buffering tank exhaust steam condensate water is replenished into the pressure-bearing buffering tank through a condensate water collection tank and a second water pump. Non-condensible gas is discharged at the same time. Buffering tank discharged water is delivered into a high-pressure deoxygenization device through a first water pump. A deoxygenization tank water discharge pipe is connected into a boiler water replenishing pipe through a third pump. A sewage discharge pipe is connected to a bottom plate of the pressure-bearing buffering tank. The device provided by the invention has the advantages of high condensate water residual heat utilization rate and reliable operation.

Description

technical field [0001] The invention relates to a secondary deaeration device for desalination of condensed water and indirect heat exchange for exhausted steam recovery, which can be used for the recovery of high-temperature condensed water and heated desalinated water produced in the production line of an alkali plant. Background technique [0002] In order to prevent thermal equipment and its pipelines from corroding, and prevent non-condensable gases from mixing into steam to reduce steam quality, dissolved oxygen and other non-condensable gases dissolved in boiler make-up water must be removed, often through deaerators. According to Henry's law and Dalton's law, for various gases dissolved in water, under a certain pressure, the higher the temperature of the water, the lower the solubility; or under a certain pressure, the lower the partial pressure of the gas, the gas the lower the solubility. Thermal deoxygenation means that when the boiler replenishment water is hea...

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Problems solved by technology

[0004] The above recovery methods have the following disadvantages: 1. The deaerator is atmospheric type, and the working temperature is about 104°C, but the actual temperature after mixing the condensed water and desalinated water is far higher than 104°C, so the excess part can only pass through the deaerator head A large amount of flash tank connected to the deaerator is empty, wasting a lot of waste heat and water resources

2. The temperature difference between condensed water and desalinated water is large. It is difficult to achieve a balance of heat in an instant through direct mixing and heat transfer. Therefore, thermal explosion is prone to occur in the deaeration box, which affects the safe operation of equipment.

3. There is a contradiction between the intermittent water replenishment of the boiler and the continuity of condensed water generation: when the boiler does not replenish water or the amount of water replenished is not large, the opening of the valve for the condensed water entering the deaerator of the calciner is small, the pressure of the system is suppressed, and the calciner grate The condensate water is not smooth; when the boiler replenishes a large amount of water, the valve opening of the calciner condensate water into the deaerator is large, the back pressure of the system is reduced, and the calciner steam is connected to the deaerator, which intensifies the discharge of waste heat

4. The volume of the deaeration box is limited, and it cannot form an effective buffer between the boiler unit and the production unit

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