A kind of CFB boiler emergency water compensating system without emergency water compensating case
Technical field
The present invention relates to CFB boiler technology field, especially relate to a kind of CFB boiler emergency water compensating system without emergency water compensating case.
Background technology
CFB (English full name Circulating Fluidized-bed Boiler, CFBB) boiler because of its have that fuel tolerance is wide, efficiency of combustion is high, Load Regulation is large, can be in bed direct desulfurization and be easy to realize the many merits such as ash comprehensive utilization, in process steam, heat supply, cogeneration of heat and power, station boiler, be widely adopted.For CFB boiler, in feedwater, have no progeny, a large amount of accumulation of heats due to bed material and refractory material in stove, cause the working medium in stove to be constantly heated, a large amount of steam will be disposed to atmosphere or be entered condenser by turbine by pass by safety valve, and main feed pump can not put into operation make loss water can not get supplementing.Lack the cooling of steam medium, be especially arranged in heating surface and the stronger heating surface pipe material of raying heat in external bed, for example the cold Bao Qiang of water-cooling wall top or vapour top, may damage even and burn because of overtemperature.Therefore, for guaranteeing the safety of water-cooling wall and other heating surface in the situation that boiler feedwater is interrupted, prevent from causing the overheated even overtemperature of tube wall due to a large amount of accumulation of heats of bed material and refractory material in stove, for CFB boiler arranges a set of emergency water compensating system, it is the most effective measure, in addition, this emergency water compensating system can also be in case of emergency provides desuperheating water and provides cooling water inflow for cone valve for Steam Turbine Bypass System.
Existing CFB boiler emergency water compensating system is mainly comprised of an independent emergency water compensating case and a set of emergency water compensating pump, coming from of the moisturizing water sweet-water tank of emergency water compensating case, the demineralized water of changing in water sweet-water tank is pumped to emergency water compensating case by demineralized water, by emergency water compensating pump, the demineralized water in emergency water compensating case is delivered in the high-pressure feed water pipeline before boiler economizer to supply water to boiler heating surface, emergency water compensating pump centre tap is drawn as the cooling water pipeline to ash control valve again.At emergency water compensating delivery side of pump, be provided with self-operated type minimum flow regulating valve, when emergency water compensating pump discharge pressure is higher than when setting value, part moisturizing by self-operated type minimum flow regulating valve will be back to emergency water compensating case, the closed circuit water while trying out weekly as emergency water compensating pump simultaneously.Because emergency water compensating system is for a long time in stand-by state, the water quality in emergency water compensating case will degenerate through certain hour, therefore, must regularly to emergency water compensating case, clean and water filling again.During the periodic maintenance of emergency water compensating case or the water system of emergency water compensating case break down; for example, when desalination water pump group breaks down; if the water supply system of CFB boiler breaks down or the abnormal conditions such as interruption; and emergency water compensating system cannot carry out normal moisturizing, thereby be easy to cause that boiler heating surface can not get in time, effectively cooling water protection.
Summary of the invention
The technical problem to be solved in the present invention is: the problem existing for prior art; a kind of CFB boiler emergency water compensating system without emergency water compensating case is provided, when the water supply system of boiler is interrupted, can not only guarantees that boiler heating surface is protected timely and effectively; and operating cost is low, environment-friendly water-saving.
The technical problem to be solved in the present invention realizes by the following technical solutions: a kind of CFB boiler emergency water compensating system without emergency water compensating case, comprising water sweet-water tank and emergency water compensating pump, on describedization water sweet-water tank, be provided with delivery port and water return outlet, change between the delivery port of water sweet-water tank and the water inlet of emergency water compensating pump and be connected by pipeline, the delivery port of emergency water compensating pump and self-operated type minimum flow regulating valve recirculation port, between the water return outlet of change water sweet-water tank, by pipeline, connect successively, between the delivery port of described self-operated type minimum flow regulating valve and Boiler High Pressure feedwater piping, by pipeline, be connected.
Preferably, describedization water sweet-water tank is at least provided with two, between the water inlet of the delivery port of describedization water sweet-water tank with parallel way and emergency water compensating pump, by pipeline, be connected, the water return outlet of describedization water sweet-water tank is connected by pipeline with between parallel way and self-operated type minimum flow regulating valve recirculation port.
Preferably, in the connecting pipe between the water return outlet of describedization water sweet-water tank and self-operated type minimum flow regulating valve recirculation port, be provided with the first stop valve.
Preferably, connecting hose in the connecting pipe between described the first stop valve and the water return outlet of change water sweet-water tank.
Preferably, in the connecting pipe between the delivery port of describedization water sweet-water tank and the water inlet of emergency water compensating pump, be provided with butterfly valve.
Preferably, connecting hose in the connecting pipe between described butterfly valve and the water inlet of emergency water compensating pump.
Preferably, in the connecting pipe between described butterfly valve and the water inlet of emergency water compensating pump, filter screen is set.
Preferably, in the connecting pipe between described self-operated type minimum flow regulating valve delivery port and Boiler High Pressure feedwater piping, be connected with check-valves.
Preferably, in the connecting pipe between described check-valves and self-operated type minimum flow regulating valve, be serially connected with the second stop valve, pneumatic control valve and the 3rd stop valve.
Compared with prior art, the invention has the beneficial effects as follows: because emergency water compensating pump is directly from changing the water inlet of water sweet-water tank, at boiler normal operation period, change water sweet-water tank in normal input state, make the water quality of water tank guaranteed, avoided the problem of demineralized water because causing water quality to degenerate for a long time in water tank; Simultaneously; because technical solution of the present invention can avoid arranging independent emergency water compensating case; simplified the emergency water compensating system of boiler; be conducive to improve the reliability of water charging system work; when the feed water system of boiler occurs to interrupt; can guarantee that boiler heating surface obtains effective protection of the cooling water that emergency water compensating system provides in time; and; adopt the technical solution of the present invention needn't frequent clean emergency water compensating case; also needn't refill demineralized water for emergency water compensating case; greatly saved construction cost and the operating cost of CFB boiler, and environment-friendly water-saving.In addition, because power plant's water sweet-water tank at least arranges 2, when one of them water tank is isolated for some reason, another water tank is in standby, to guarantee the long-term standby reliability of emergency water compensating system, the defect that while having made up the periodic maintenance of emergency water compensating case, emergency water compensating can not drop into.
Accompanying drawing explanation
Fig. 1 is the structural map of a kind of CFB boiler emergency water compensating system without emergency water compensating case of the present invention.
Mark in figure: 1-flexible pipe, 2-the first stop valve, 3-the second stop valve, 4-pneumatic control valve, 5-the 3rd stop valve, 6-check-valves, 7-self-operated type minimum flow regulating valve, 8-flow nozzle, 9-filter screen, 10-butterfly valve.
The specific embodiment
In order to make object of the present invention, technical scheme and advantage clearer, below in conjunction with the drawings and specific embodiments, the present invention is described in detail.Should be appreciated that specific embodiment described herein, only in order to explain the present invention, is not intended to limit the present invention.
A kind of CFB boiler emergency water compensating system without emergency water compensating case as shown in Figure 1; comprising water sweet-water tank, emergency water compensating pump and self-operated type minimum flow regulating valve 7; on describedization water sweet-water tank, be provided with locus higher than the water return outlet of delivery port; on the delivery port pipeline of describedization water sweet-water tank, connect butterfly valve 10; described butterfly valve 10 is connected with the water inlet pipeline of emergency water compensating pump by flexible pipe 1; flexible pipe 1 wherein can increase the flexibility that pipeline connects, and is conducive to protect the safety of butterfly valve 10 and connecting pipe.In order to guarantee, improve to enter the cleannes of the demineralized water in emergency water compensating pump, in the connecting pipe between butterfly valve 10 ports of export and the water inlet of emergency water compensating pump, filter screen 9 is also set, by filter screen 9, can carry out filtration to a certain degree to the demineralized water entering in emergency water compensating pump, improve the salt water quality that enters emergency water compensating pump, be conducive to extend the service life of emergency water compensating pump.
The water return outlet of describedization water sweet-water tank is connected and communicates with the first stop valve 2 by flexible pipe 1, the first stop valve 2 is connected and is communicated by pipeline with the recirculation port of self-operated type minimum flow regulating valve 7, the delivery port of self-operated type minimum flow regulating valve 7 with between Boiler High Pressure feedwater piping is connected by pipeline, and the water inlet of self-operated type minimum flow regulating valve 7 with between the delivery port of emergency water compensating pump is connected by pipeline.Flexible pipe 1 wherein can increase the flexibility of connecting pipe, and the installation of being convenient to pipeline regulates, thereby plays certain shock-absorbing protecting effect to changing water sweet-water tank, self-operated type minimum flow regulating valve 7 and the first stop valve 2.
In addition, as shown in Figure 1, describedization water sweet-water tank can arrange two, is divided into the first change water sweet-water tank and second and changes water sweet-water tank, and described the first change water sweet-water tank, second is changed water sweet-water tank with in parallel way access emergency water compensating system.Particularly, the first delivery port pipeline of changing water sweet-water tank, the second change water sweet-water tank is connected successively with independent butterfly valve 10, flexible pipe 1 respectively, two flexible pipes 1 are connected and communicate with the pipeline at filter screen 9 places more simultaneously, and filter screen 9 place pipelines are connected and communicate with the inlet end of emergency water compensating pump; First change water sweet-water tank, the second water return outlet pipeline of changing water sweet-water tank is connected successively with independent flexible pipe 1, the first stop valve 2 respectively, two the first stop valve 2 entrance points are connected by pipeline between the recirculation port of while and self-operated type minimum flow regulating valve 7 again.Like this, when one of them change water sweet-water tank needs to isolate for some reason, another change water sweet-water tank in standby can continue as emergency water compensating pump provides demineralized water, thereby guarantee the long-term standby reliability of emergency water compensating system, the defect that the emergency water compensating system having caused while having made up independent change water sweet-water tank because of periodic maintenance or fault can not normally drop into.
When CFB boiler operatiopn, emergency water compensating system of the present invention is the high-pressure feed water piped water supply to boiler by emergency water compensating pump, self-operated type minimum flow regulating valve 7.As shown in Figure 1, in connecting pipe between self-operated type minimum flow regulating valve 7 delivery ports and Boiler High Pressure feedwater piping, be serially connected with successively in order the second stop valve 3, pneumatic control valve 4 and the 3rd stop valve 5, in connecting pipe between self-operated type minimum flow regulating valve 7 and the second stop valve 3, be provided with check-valves 6, in connecting pipe between the 3rd stop valve 5 and Boiler High Pressure feedwater piping, be also connected with check-valves 6, by two check-valves 6 and the second stop valve 3, the 3rd stop valve 5 cooperatively interacts, make the demineralized water of emergency water compensating pump output timely, successfully be pumped to Boiler High Pressure feedwater piping, finally to economizer import header.Another delivery port of described emergency water compensating pump is connected by pipeline with ash control valve cooling water pipeline, in the connecting pipe between this another delivery port of emergency water compensating pump and ash control valve cooling water pipeline, be serially connected with pneumatic control valve 4, flow nozzle 8, the 3rd stop valve 5 and check-valves 6, simultaneously, between another delivery port of emergency water compensating pump and pneumatic control valve 4, be also serially connected with the 3rd stop valve 5, the 3rd all stop valves 5 are in normally off, the second all stop valves 3 are in normally open, so just can utilize same emergency water compensating pump to carry out moisturizing for ash control valve cooling water pipeline.It is to be noted, described the 3rd stop valve 5 and the second stop valve 3 also all can adopt electric check valve, by boiler control system, control closing or opening of each electric check valve, thereby realize the automated control operation of water charging system, saved manpower.
The present invention is applicable to the CFB boiler unit that thermal power plant need to arrange emergency water compensating system, and unit capacity is applicable to 300MW-1000MW grade unit conventionally, and unit number of units is applicable to 1 and many.After the invention process, compare with conventional traditional water charging system, power plant's water sweet-water tank is at least 2, when one of them water tank is isolated for some reason, another water tank in standby, thereby can guarantee the long-term standby reliability of emergency water compensating system, the defect that while having made up the periodic maintenance of emergency water compensating case, emergency water compensating can not drop into, when the water supply system of boiler is interrupted, can provide in time cooling water for boiler heating surface, effectively protect the security of operation of boiler; Meanwhile, owing to having cancelled independent emergency water compensating case and other pipe fittings, simplify the emergency water compensating system of CFB boiler, and needn't clean continually water tank and refill demineralized water, saved the operating cost of CFB boiler unit; Because emergency water compensating pump is directly from changing the water inlet of water sweet-water tank, at unit normal operation period, change water sweet-water tank in normal input state, it can be to system water supplements such as condensate water, therefore, the water quality of demineralized water of changing the output of water sweet-water tank is guaranteed, has avoided changing water in the water sweet-water tank problem because causing water quality to degenerate for a long time, not only environmental protection but also economize on water.
The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, it should be pointed out that all any modifications of doing within the spirit and principles in the present invention, be equal to replacement and improvement etc., within all should being included in protection scope of the present invention.