Direct current furnace condensate recovery system and method based on high and low pressure condensate flash tanks

Abstract

The invention discloses a direct current furnace condensate recovery system and method based on high and low pressure condensate flash tanks. The direct current furnace condensate recovery system comprises a separator, a separator water storage tank, the high pressure condensate flash tank, the low pressure condensate flash tank, a deaerator, a condenser, a unit drain tank, other steam users and astarting condensate pump. Condensate of the separator passes through the separator water storage tank to enter the high pressure condensate flash tank. Steam in the high pressure condensate flash tank is conveyed to the deaerator and other steam users for heat recovery, redundant steam is discharged to the low pressure condensate flash tank and is discharged to the atmosphere through an exhaust pipe. When water is qualified, the condensate is discharged to the deaerator for heat recovery, or redundant condensate is discharged to the condenser, and the working medium is recovered. When water is unqualified, the condensate is discharged into the low pressure condensate flash tank and is discharged to the unit drain tank through the starting condensate pump.

Description

technical field [0001] The invention relates to a drainage recovery system for a once-through furnace, in particular to a drainage recovery system and method for a direct-flow furnace without a start-up circulation pump based on a high-low pressure drainage expansion vessel. Background technique [0002] At present, supercritical and ultra-supercritical units have been called the main units of thermal power plants in my country. Since the once-through furnace has no steam drum and natural circulation loop, it is necessary to maintain a feed water flow rate of about 30% of the rated evaporation from the ignition to ensure the minimum flow rate of the water wall, and the boiler enters the once-through load at about 30% of the rated load condition. , so before entering the DC load, the boiler has a large amount of working fluid and heat to be discharged through the start separator and the start separator water storage tank. The current common startup systems are as follows: ...

AI Technical Summary

Problems solved by technology

Improper hydrophobic treatment will often cause the destruction of the original heat balance in the condenser, resulting in increased back pressure, affecting the output of the unit, and also causing problems such as shock, vibration, damage to the condenser tube, and shell separation.

[0009] To sum up, in the prior art, for the simple atmospheric expansion type starting system, the separated steam is discharged into the atmosphere, and the loss of working fluid and heat is relatively large, and the composite atmospheric expansion type starting system will lose part of the working fluid during the starting process And most of the heat, the start-up system of the hydrophobic heat exchanger has high investment and complex system structure, the recirculation pump start-up system is complex, high investment, high maintenance costs, and there is a risk of cavitation in the recirculation pump, and special pipelines must be installed to improve Drain subcooling, condenser start-up system does not lose working fluid during start-up, but loses most of the heat. Improper treatment of water drainage will often cause damage to the original heat balance in the condenser, resulting in increased back pressure and affecting unit output. It will also cause problems such as shock, vibration, damage to the condenser tube, and the shell is out of the way, and there is still no effective solution

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