Condensate water desalination heat exchange mixed exhaust steam recovery secondary deoxygenation exhaust steam condensing device

Abstract

The invention relates to a two-stage deoxidized exhaust steam condensing device for heat-exchange mixed exhaust steam recovery of condensate water and desalted water. A pressure-bearing buffer tank is provided with a first water inlet pipe, a second water inlet pipe, a third water inlet pipe and a fourth water inlet pipe, wherein the first water inlet pipe and the third water inlet pipe are located on the upper layer, and the second water inlet pipe and the fourth water inlet pipe are located on the lower layer; mixed condensate water is introduced into the second water inlet pipe and the fourth water inlet pipe respectively after subjected to indirect heat exchange by a third heat exchanger and a fourth heat exchanger, and synthesis ammonia desalted water and conversion desalted water are introduced into the first water inlet pipe and the third water inlet pipe respectively after subjected to indirect heat exchange of the third heat exchanger and the fourth heat exchanger; buffer tank exhaust steam is cooled into buffer tank exhaust steam condensate water by a first heat exchanger; buffer tank outlet water is sent into a high-pressure deaerator by a first water pump, and drained water of a deaerator tank is sent to a boiler water replenishing pipe by a third water pump; the deoxidized exhaust steam is cooled into deoxidized exhaust steam condensate water by a second heat exchanger, the buffer tank exhaust steam condensate water and the deoxidized exhaust steam condensate water are injected into the pressure-bearing buffer tank by a condensate water collecting tank and a second water pump, and meanwhile, gas is discharged; and a forcible mixing impeller is mounted at the middle-lower part of the pressure-bearing buffer tank. According to the device, the utilization rate of condensate water waste heat is high, and the operation is reliable.

Description

technical field [0001] The invention relates to a condensed water desalinated water heat exchange mixed exhaust steam recovery two-stage deoxygenated exhaust steam condensing device, which can be used for 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 wate...

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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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