Novel (ultra) supercritical boiler starting system

Abstract

The invention discloses a novel (ultra) supercritical boiler starting system which comprises a deaerator. A high-pressure heater is arranged at the outlet end of the deaerator. A coal economizer is arranged at the outlet end of the high-pressure heater. A water cooling wall is arranged at the outlet end of the coal economizer. The outlet end of the water cooling wall is connected with a steam-water separator. The outlet end of the steam-water separator is connected to the inlet end of the deaerator through a steam-water separator high water level adjusting valve and a steam-water separator low water level adjusting valve which are connected in parallel. The novel (ultra) supercritical boiler starting system is simple in structure and low in investment cost, and the operation safety and reliability are substantially improved compared with existing starting systems with heat exchangers in China. The system can conducted sectioned precise control on the water level while discharging pollutants, recycling heat and reducing energy consumption, and the situation that when a boiler is started, equipment is damaged due to a drain discharge pressure head and too large steam-water expansion amount can be avoided.

Description

technical field [0001] The invention belongs to the technical field of boilers, and in particular relates to a novel super (super) critical boiler startup system. Background technique [0002] Although the starting systems used in domestic ultra (super) critical boilers are different, they can basically be classified into two categories: the starting system with the starting circulation pump and the starting system without the starting circulation pump. Although starting the circulation pump can recover the saturated water and its heat separated by the steam-water separator, the cost of the pump system is high and the investment is large. At present, almost all the starting circulation pumps are imported, and the cost is very high. Submersible motors are mostly used. Once the cooling system fails, it is easy to cause damage to the pump and the system reliability is insufficient. Although the starting system without the starting circulation pump is simple, reliable and low i...

AI Technical Summary

Problems solved by technology

Although starting the circulation pump can recover the saturated water and its heat separated by the steam-water separator, the cost of the pump system is high and the investment is large. At present, almost all the starting circulation pumps are imported, and the cost is very high. Submersible motors are mostly used. Once the cooling system fails, it is easy to cause damage to the pump and the system reliability is insufficient.

Although the starting system without the starting circulation pump is simple, reliable and low in cost, it can only recover a small part of the saturated water and its heat separated by the steam-water separator, and the loss of working fluid and heat is relatively large

[0003] The start-up system with a hydrophobic heat exchanger currently used in our country can recover the working fluid and part of the heat and the system is relatively simple, but when the water quality is not up to standard, the sewage discharge performance of the system is poor

When the boiler is started in a cold state, the drain pressure head and the expansion of steam and water are too large to cause equipment damage

During the hot start of the boiler, when the working pressure of the steam-water separator is higher than or equal to a certain pressure, the trap valve of the steam-water separator is self-locked, and most of the water drained from the steam-water separator can only be discharged into the deaerator water tank after the water temperature is lowered by the drain heat exchanger. As a result, the pressure of the deaerator water tank increases, and the safety valve jumps, which not only wastes heat and working fluid, but also pollutes the surrounding environment

Although it takes only a few minutes for the safety valve to release steam and return to its seat, it has a great impact

In addition, in the domestic starting system with drain heat exchanger, the drain of the steam-water separator is only controlled by the bypass valve, and the water level of the steam-water separator cannot be controlled in sections, so the safety is not high

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