CN103953915B

CN103953915B - High-pressure heater reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat

Info

Publication number: CN103953915B
Application number: CN201410210176.XA
Authority: CN
Inventors: 章礼道
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-05-19
Filing date: 2014-05-19
Publication date: 2016-03-30
Anticipated expiration: 2034-05-19
Also published as: CN103953915A

Abstract

The method that high-pressure heater of the present invention reclaims the hydrophobic working medium of double reheat boiler startup and heat relates to the nothing startup boiler water circulating pump of a kind of power station supercritical double-reheat boiler use and can reclaim the method starting hydrophobic working medium and heat comprehensively.4 of steamer pusher side high-pressure heaters of connecting are used as water water heat exchanger by the present invention during the supercritical double-reheat boiler startup of power station, at shell-side, to the hydrophobic echelon pressure and temperature reducing of double reheat boiler startup, high enthalpy enters oxygen-eliminating device after starting hydrophobic echelon releasing heat; In pipe side, after the feed pump outlet high-pressure feed water echelon absorption heat of lower enthalpy, enter economizer.The two cover control logics of unit DCS to high-pressure heater of particular design ensure that the equal energy safety of each high-pressure heater, complete double reheat boiler startup overall process and heat regenerative system mode of operation economically.Various start operating performance, starts overall process and all can reclaim working medium and heat comprehensively, and recovering effect is better than there is the direct current furnace starting system starting boiler water circulating pump.Without starting boiler water circulating pump and subsystem thereof, significantly reduce capital expenditure and operation and maintenance cost and without iron pollution.

Description

High-pressure heater reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat

(1) technical field:

The method that high-pressure heater of the present invention reclaims the hydrophobic working medium of double reheat boiler startup and heat relates to the nothing startup boiler water circulating pump of a kind of power station supercritical double-reheat boiler use and can reclaim the method starting hydrophobic working medium and heat comprehensively.

(2) background technology:

Power station supercritical double-reheat boiler must be Once-through Boiler.

The power station supercritical double-reheat boiler start-up system of prior art is an important component part of power station supercritical double-reheat boiler plant, the object arranging start up system is in boiler startup, underrun and furnace shutting down process, set up by start up system and maintain the minimum mass flow in water-cooling wall, to protect water-cooling wall safety; Meet unit safety, economic start and stop simultaneously; Performing low-load running of machine set and carry out accident treatment rapidly, and realize the requirement of working medium and heat recovery as far as possible.

What the power station supercritical DC furnace start up system of prior art was conventional has 4 kinds:

A has startup boiler water circulating pump, has the direct current furnace starting system of atmospheric drainage flash tank, drain tank, drainage pump.(Fig. 1)

B has startup boiler water circulating pump, the direct current furnace starting system of the hydrophobic in line condenser of boiler startup.(Fig. 2)

C, without startup boiler water circulating pump, has the direct current furnace starting system of atmospheric drainage flash tank, drain tank, drainage pump.(Fig. 3)

D is without starting boiler water circulating pump, the direct current furnace starting system of the hydrophobic in line condenser of boiler startup.(Fig. 4)

A kind direct current furnace starting system is when starting boiler water circulating pump and normally working, it is generally acknowledged, except a few minutes that Once-through Boiler crosses the phase of expansion, working medium and heat can be reclaimed comprehensively, but in fact in order to make separator water level control valve and corresponding pipeline, valve exempts from excessive thermal shock, from Once-through Boiler igniting have an appointment always 20% startup flow be admitted to atmospheric drainage flash tank, this part working medium and heat substantially all lost; Still can clean boot Once-through Boiler when starting boiler water circulating pump fault, but deteriorated to C kind direct current furnace starting system.

B kind direct current furnace starting system is when starting boiler water circulating pump and normally working, it is generally acknowledged, except a few minutes that Once-through Boiler crosses the phase of expansion, working medium and heat can be reclaimed comprehensively, but in fact in order to make separator water level control valve and corresponding pipeline exempt from excessive thermal shock, from Once-through Boiler igniting have an appointment always 20% startup flow be admitted to condenser, this part heat basic loss has fallen; Still can clean boot Once-through Boiler when starting boiler water circulating pump fault, but deteriorated to D kind direct current furnace starting system.

C kind direct current furnace starting system is when being furnished with Liquid level bypass valve, and small part operating mode can reclaim working medium and heat; Boiler startup is hydrophobic when entering atmospheric drainage flash tank, and can be subject to serious iron pollution, now not only heat can not reclaim but also working medium also should not reclaim; Due to atmospheric drainage flash tank to be generally arranged in boiler structure or near, atmospheric drainage flash tank exports later pipeline and is low pressure pipeline, is easy to arrange, is easy to hang, make A kind and C kind direct current furnace starting system once obtain more employing; Due to misgivings oxygen-eliminating device superpressure, A kind and the C kind direct current furnace starting system quantity of being furnished with Liquid level bypass valve are little.

D kind direct current furnace starting system is when being furnished with Liquid level bypass valve, and small part operating mode can reclaim working medium and heat; The hydrophobic in line condenser of boiler startup is without iron pollution, and recyclable whole working medium, can not reclaim heat.B kind and D kind direct current furnace starting system obtain more employing in recent years; Due to misgivings oxygen-eliminating device superpressure, B kind and the D kind direct current furnace starting system quantity of being furnished with Liquid level bypass valve are little.

C kind and D kind direct current furnace starting system are when being furnished with Liquid level bypass valve, small part operating mode can reclaim working medium and heat, Liquid level bypass valve allows the representative condition opened to be that oxygen-eliminating device pressure is not not less than 2.7m tri-conditions and meets, to guarantee oxygen-eliminating device safety simultaneously higher than 11.0MPa, steam-water separator water level higher than 0.5MPa, steam-water separator pressure.

High-pressure heater is a part for power station steam turbine group heat regenerative system, for reducing the cold end loss of power station thermodynamic cycle, improves the thermal efficiency in power station.The typical high-pressure heater of prior art Double reheat steam turbine group is generally horizontal, U-shaped heat-transfer pipe, shell-and-tube heat exchanger; 4 grades of arranged in series, accept steam turbine ultra-high pressure cylinder steam discharge respectively, high pressure cylinder draw gas, high pressure cylinder steam discharge, intermediate pressure cylinder prime are drawn gas; And the steam condenser of separate type is set; For the boiler feedwater of stepped heating feed pump outlet.The hydrophobic of high-pressure heater is refluxed step by step, the hydrophobic of No. 4 high-pressure heaters is back to oxygen-eliminating device, the hydrophobic outlet of every platform high-pressure heater is all furnished with outlet drain regulating valve, monitor by unit DCS (dcs), in order to the hydrophobic water level of each high-pressure heater of regulable control at target interval, make the energy-saving effect of heat regenerative system maximize and prevent turbine water induction, guarantee Steam Turbine safety, economical operation.

High-pressure heater is usually with steam turbine host-initiated; The usual sliding pressure operation of oxygen-eliminating device.

It is the phenomenon that the steam-water separator water level occurred when water screen system starts to steam jumps, the hydrophobic pulsed of boiler startup increases that water-cooling wall crosses expansion, its reason is that in water screen system, working medium severe declines fast, it is a kind of transient process, about 3,4 minutes duration, the hydrophobic incremental integration value of boiler startup is 30 to 50t to 1000MW grade Once-through Boiler representative value.

(3) summary of the invention:

Technical problem to be solved:

As mentioned above, A kind and B kind are furnished with the direct current furnace starting system starting boiler water circulating pump can reclaim working medium and heat comprehensively, but for making startup boiler water circulating pump system worked well, needs arrange startup boiler water circulating pump recirculation subsystem, startup boiler water circulating pump warming-up subsystem, startup boiler water circulating pump entrance subcooled water subsystem, startup boiler water circulating pump high pressure washing and moisturizing subsystem, the cooling of startup boiler water circulating pump low pressure water subsystem, 6kV/10kV station-service electric power system, DCS control system; System complex fault is many, responsive to stove water endoparticle thing; Start boiler water circulating pump to need to work under supercritical pressure and hot conditions, domesticly still can not to produce, 2 1000MW grade units arrange and start boiler water circulating pump and subsystem thereof, and power station investment about increases by 2,000 ten thousand yuan; After start-up course completes, start boiler water circulating pump system and be still in pressure-bearing hot stand-by state, the year energy consumption cost unit up to a million of stand-by heat, also will drop into the inspection of unit up to a million, maintenance, recondition expense in addition every year.Is furnished with the start up system of startup boiler water circulating pump from ignition of the boiler, until water-cooling wall cross expand terminate have an appointment always 20% startup flow be admitted to air suspended type flash vessel or condenser, the heat of this part working medium can not reclaim, and is admitted to the hydrophobic major reason often becoming feedwater iron-holder and exceed standard of air suspended type flash vessel.

A kind ofly need not start the double reheat boiler start-up system that boiler water circulating pump can reclaim again working medium and heat comprehensively therefore, it is possible to find and have substantial economics, be the Important Techmical Progress in double reheat boiler start-up system field, power station.

Solve the technical scheme that its technical problem adopts:

High-pressure heater of the present invention reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat and aforementioned A kind, B kind direct current furnace starting system is different, the hydrophobic method returning economizer entrance of startup starting the outlet of boiler water circulating pump supercharging steam-water separator water storage tank is not used to reclaim working medium and heat, but postpone the enabled instruction of high-pressure heater as power station steam turbine group heat regenerative system of 4 series connection of steamer pusher side, during the supercritical double-reheat boiler startup of power station, 4 of steamer pusher side tandem high pressure heaters are used as water water heat exchanger, at shell-side, to the hydrophobic echelon pressure and temperature reducing of double reheat boiler startup, high enthalpy enters oxygen-eliminating device after starting hydrophobic echelon releasing heat, in pipe side, after the high-pressure feed water echelon absorption heat of the feed pump outlet of lower enthalpy, enter economizer.Because the exchange capability of heat of 4 high-pressure heaters is by 100%BMCR flow design, have the heat exchange area of enormous quantity, DC furnace start-up drainage flow is from igniting to boiler band minimal once-through circulation load, flow mobility scale is 0 to 30%BMCR/0 to 25%BMCR, when 4 tandem high pressure heaters are used as water water heat exchanger, terminal temperature difference can be no more than 10K.

When high-pressure heater is used as water water heat exchanger between the Once-through Boiler starting period, what pipe sidled is the high-pressure feed water that feed pump exports, what shell-side was walked is that boiler startup is hydrophobic, and pipe effluent amount before expanding of crossing from ignition of the boiler to water-cooling wall is substantially equal with shell-side flow, and oxygen-eliminating device pressure slowly rises; Complete before boiler proceeds to full direct current operating mode to start-up course after water-cooling wall crosses and expands, pipe effluent amount is constant, and shell-side flow drops to 0 gradually by the hydrophobic amount of maximum startup, corresponding, and oxygen-eliminating device pressure drops to stopping by climbing speed and rises to slow decline; A few minutes inner casing effluent amount of only crossing expansion at water-cooling wall is quite greater than pipe effluent amount, if be again start under very hot state operating mode, oxygen-eliminating device pressure likely rises fast, for guaranteeing that following measures are taked in oxygen-eliminating device safe operation:

Before water-cooling wall crosses and expands, oxygen-eliminating device maintains low water level, and low enthalpy condensate water is entered in a few minutes inter-sync of crossing expansion at water-cooling wall;

Before water-cooling wall crosses and expands, separator maintains low water level;

Select built-in deaerator, oxygen-eliminating device maximum allowable working pressure is brought up to 2.0MPa;

Connect a pipeline to condenser low voltage bypass entrance from oxygen-eliminating device air removal section, above quck-opening valve is installed, control oxygen-eliminating device pressure;

Adopt above 4 measures simultaneously.

Very hot startup is the operating mode that most probable causes oxygen-eliminating device superpressure, like this, no matter cold start, warm starting, hot starting, hot start, very hot startup all can will start hydrophobic introducing oxygen-eliminating device safely, working medium in the supercritical double-reheat boiler startup process of comprehensive recovery power station and heat, obtain the effect better more fully reclaiming working medium and heat than the direct current furnace starting system being furnished with startup boiler water circulating pump.

It is guarantee that high-pressure heater admission stop valve and high-pressure heater admission non-return valve tightly do not leak and can real-time verification that high-pressure heater is used as the necessary condition of water water heat exchanger between the Once-through Boiler starting period, each high-pressure heater admission stop valve and be provided with pressure sensor between high-pressure heater admission non-return valve state of the art good, each high-pressure heater admission stop valve and high-pressure heater admission non-return valve and observable drain valve can meet this condition.

Check and revise the flow area of the import of drawing gas of No. 1 high-pressure heater (44) and the Kv value of separator water level control valve (31), the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, steam-water separator (6) is no more than 1.0MPa with the pressure reduction of No. 1 high-pressure heater (44) shell-side.Check that the draw gas strike plate of import of confirmation No. 1 high-pressure heater (44) is enough to bear the hydrophobic impact of boiler startup, U-tube group can not be damaged, if desired reinforcement strike plate.Check and revise the HP heater drainage inlet flow area of the hydrophobic outlet flow area of No. 1 high-pressure heater (44), the Kv value of No. 1 HP heater drainage control valve (48) and No. 2 high-pressure heaters (45), the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 1 high-pressure heater (44) is not higher than 8MPa; Check and revise the HP heater drainage inlet flow area of the hydrophobic outlet flow area of No. 2 high-pressure heaters (45), the Kv value of No. 2 HP heater drainage control valves (49) and No. 3 high-pressure heaters (46), the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 2 high-pressure heaters (45) is not higher than 5.4MPa; Check and revise the HP heater drainage inlet flow area of the hydrophobic outlet flow area of No. 3 high-pressure heaters (46), the Kv value of No. 3 HP heater drainage control valves (50) and No. 4 high-pressure heaters (47), the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 3 high-pressure heaters (46) is not higher than 3.4MPa; Check and revise the HP heater drainage inlet flow area of the hydrophobic outlet flow area of No. 4 high-pressure heaters (47), the Kv value of No. 4 HP heater drainage control valves (51) and oxygen-eliminating device (22), the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 4 high-pressure heaters (47) is not higher than 2.3MPa.No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) such as to be at hundred parts of ratio characteristics.

Double reheat power generation sets 4 high-pressure heater housing design pressure are quite higher than the pressure born during for reclaiming the hydrophobic working medium of double reheat boiler startup and heat.4 high-pressure heaters, in boiler startup process, hydrophobic start hydrophobic heat and pass to feedwater with countercurrent heat exchange method as same the distributed temperature-decreased pressure reducer having a huge exchange capability of heat starting, and to reduce after enthalpy hydrophobic is reclaimed by oxygen-eliminating device.

The present invention includes steam-water separator (6), steam-water separator water storage tank (7), water storage tank outlet shutoff valve (53), separator water level control valve (31), No. 1 high adds admission stop valve (40), No. 2 high adds admission stop valve (41), No. 3 high adds admission stop valve (42), No. 4 high adds admission stop valve (43), No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47), No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51), oxygen-eliminating device (22), oxygen-eliminating device decompression exhaust steam valve (52) and unit DCS (dcs), between the Once-through Boiler starting period, No. 1 high adds admission stop valve (40), No. 2 highly add admission stop valve (41), No. 3 highly add admission stop valve (42), No. 4 high admission stop valves (43) that add all are in close stance, and shell-side and the turbine steam extraction system of the shell-side of No. 1 high-pressure heater (44), the shell-side of No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) are reliably isolated, steam-water separator water storage tank (7) startup is out hydrophobic through water storage tank outlet shutoff valve (53), separator water level control valve (31) enters the shell-side of No. 1 high-pressure heater (44), after cooling, through No. 1 HP heater drainage control valve (48) decompression, enter the shell-side of No. 2 high-pressure heaters (45), after cooling, through No. 2 HP heater drainage control valve (49) decompressions, enter the shell-side of No. 3 high-pressure heaters (46), after cooling, through No. 3 HP heater drainage control valve (50) decompressions, enter, the shell-side of No. 4 high-pressure heaters (47), after cooling, through No. 4 HP heater drainage control valve (51) decompressions, enter oxygen-eliminating device (22), the control logic of outlet drain regulating valve when high-pressure heater is used as water water heat exchanger of high-pressure heater is completely different as control logic during heat regenerative system from high-pressure heater, unit DCS (dcs) must have the different control logic of 2 covers, switches in good time, when high-pressure heater is used as water water heat exchanger, the outlet drain regulating valve of No. 1 high-pressure heater is for controlling the pressure differential between No. 1 high-pressure heater shell-side and No. 2 high-pressure heater shell-sides, the outlet drain regulating valve of No. 2 high-pressure heaters is for controlling the pressure differential between No. 2 high-pressure heater shell-sides and No. 3 high-pressure heater shell-sides, the outlet drain regulating valve of No. 3 high-pressure heaters is for controlling the pressure differential between No. 3 high-pressure heater shell-sides and No. 4 high-pressure heater shell-sides, the outlet drain regulating valve of No. 4 high-pressure heaters is for controlling the pressure differential between No. 4 high-pressure heater shell-sides and oxygen-eliminating device, the adjustment target being governor motion with the outlet drain regulating valve of each high-pressure heater is the shell pressure of each corresponding high-pressure heater, regulate desired value and instant oxygen-eliminating device pressure, steam-water separator pressure relevant, the shell pressure desired value of No. 1 high-pressure heater is that steam-water separator pressure subtracts 1.0MPa, and the shell pressure desired value of No. 4 high-pressure heaters is that oxygen-eliminating device pressure adds 1.0MPa, the shell pressure desired value of No. 2 high-pressure heaters be No. 3 high-pressure heater shell pressures add No. 1 high-pressure heater of 0.54 times and No. 4 high-pressure heater shell pressures poor, the shell pressure desired value of No. 3 high-pressure heaters be No. 4 high-pressure heater shell pressures add No. 1 high-pressure heater of 0.2 times and No. 4 high-pressure heater shell pressures poor, feed pump (15) sucks low pressure feed water from oxygen-eliminating device (22), high-pressure feed water is become after supercharging, through feed pump outlet valve (14), flow through the pipe side of No. 4 high-pressure heaters (47), No. 3 high-pressure heaters (46), No. 2 high-pressure heaters (45), No. 1 high-pressure heater (44) successively, enter economizer (5) after cascade raising temperature, complete comprehensive recovery of working medium and heat, when the large discharge that very hot startup water-cooling wall crosses expansion starts hydrophobic passing through, No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valve (51) standard-sized sheets, oxygen-eliminating device (22), with the low enthalpy condensate water of stepping, controls the pressure of oxygen-eliminating device (22) not higher than 1.5MPa.

The control logic of outlet drain regulating valve when high-pressure heater is used as water water heat exchanger of high-pressure heater is completely different as control logic during heat regenerative system from high-pressure heater, unit DCS (dcs) must have the different control logic of 2 covers, switches in good time.When high-pressure heater is used as water water heat exchanger, the outlet drain regulating valve of No. 1 high-pressure heater is for controlling the pressure differential between No. 1 high-pressure heater shell-side and No. 2 high-pressure heater shell-sides; The outlet drain regulating valve of No. 2 high-pressure heaters is for controlling the pressure differential between No. 2 high-pressure heater shell-sides and No. 3 high-pressure heater shell-sides; The outlet drain regulating valve of No. 3 high-pressure heaters is for controlling the pressure differential between No. 3 high-pressure heater shell-sides and No. 4 high-pressure heater shell-sides; The outlet drain regulating valve of No. 4 high-pressure heaters is for controlling the pressure differential between No. 4 high-pressure heater shell-sides and oxygen-eliminating device.The adjustment target being governor motion with the outlet drain regulating valve of each high-pressure heater is the shell pressure of each corresponding high-pressure heater, regulate desired value and instant oxygen-eliminating device pressure, steam-water separator pressure relevant, the shell pressure desired value of No. 1 high-pressure heater is that steam-water separator pressure subtracts 1.0MPa, and the shell pressure desired value of No. 4 high-pressure heaters is that oxygen-eliminating device pressure adds 1.0MPa; The shell pressure desired value of No. 2 high-pressure heaters be No. 3 high-pressure heater shell pressures add No. 1 high-pressure heater of 0.54 times and No. 4 high-pressure heater shell pressures poor; The shell pressure desired value of No. 3 high-pressure heaters be No. 4 high-pressure heater shell pressures add No. 1 high-pressure heater of 0.2 times and No. 4 high-pressure heater shell pressures poor.Above-mentioned high-pressure heater is used as control logic during water water heat exchanger, its objective is and makes the heat exchange amount between the hydrophobic and high-pressure feed water of startup maximize under the premise that security is guaranteed.

When cold start, warm starting, hot starting, hot start, very hot startup, steam-water separator pressure gets 6MPa to 9MPa respectively, and lower value is got in cold start, and very hot startup gets high value, and warm starting, hot starting, hot start get median; In start-up course, steam-water separator pressure can use aperture and the fuel regulation of super-pressure bypass valve, high pressure bypass valve, low voltage bypass valve.

Separator water level control valve (31) is a cage spool control valve, Deng hundred parts of ratio characteristics, valve casing can bear supercritical pressure, and its Kv value should to ensure when its inlet outlet pressure differential is 0.5MPa large discharge when can cross expansion by very hot startup water-cooling wall.Due to separator water level control valve (31), to import and export pressure ratio little, without serious cavitation, without the need to being split into 2 or 3 control valves in parallel.

Oxygen-eliminating device (22) is built-in deaerator, the highest permission operating pressure 2.0MPa, and Steam Turbine at full capacity sliding pressure operation of deaer pressure is no more than 1.3MPa, Once-through Boiler when very hot startup oxygen-eliminating device pressure not higher than 1.5MPa; Oxygen-eliminating device (22) is provided with oxygen-eliminating device decompression exhaust steam valve (52), and when the unusual service condition of pressure higher than 1.5MPa appears in oxygen-eliminating device (22), open fast, steam enters the low voltage bypass entrance of condenser (25); When oxygen-eliminating device pressure returns to 1.0MPa, oxygen-eliminating device decompression exhaust steam valve (52) cuts out automatically.Oxygen-eliminating device decompression exhaust steam valve (52) is when opening, and oxygen-eliminating device decompression exhaust steam valve (52) outlet pressure is no more than 0.7MPa, and the built-in energy dissipator of condenser (25) can accept safely; Oxygen-eliminating device decompression exhaust steam valve (52) relieving capacity when inlet pressure 1.5MPa is 0.075BMCR mass flow.

The shell-side of No. 1 high-pressure heater (44) and supercritical pressure reliably can be isolated when water storage tank outlet shutoff valve (53) is closed; Pressure sensor and observable drain valve is provided with to confirm that water storage tank outlet shutoff valve (53) is closed tightly between water storage tank outlet shutoff valve (53) and separator water level control valve (31).

After power station supercritical DC furnace reaches minimal once-through circulation load, steam-water separator (6) is in dry state, micro-superheat state, separator water level control valve (31) complete shut-down, each HP heater drainage control valve complete shut-down, close water storage tank outlet shutoff valve (53), the shell-side of tight isolation steam-water separator water storage tank (7) and No. 1 high-pressure heater (44); The control logic of unit DCS (dcs) to the outlet drain regulating valve of each high-pressure heater is switched to high-pressure heater water lev el control pattern; Open each high-pressure heater air inlet stop valve; Start each high-pressure heater and recover heat regenerative system mode of operation.

Pipeline thermal back-up system between the steam-water separator water storage tank (7) that the present invention does not need the various direct current furnace starting system of prior art to have to separator water level control valve (31), because after No. 1 high-pressure heater recovers heat regenerative system mode of operation, steam turbine high-pressure cylinder draws gas and makes the pipeline between the shell-side of No. 1 high-pressure heater (44) and No. 1 high-pressure heater (44) shell-side to separator water level control valve (31) remain on hot; Otherwise the process that 4 high-pressure heaters are used as water water heat exchanger is also the good preheating each high-pressure heater being returned to heat regenerative system state.

The present invention utilizes 4 high-pressure heaters of steamer pusher side between the power station supercritical DC furnace starting period, as water water heat exchanger, to DC furnace start-up drainage echelon pressure and temperature reducing, high enthalpy starts hydrophobic echelon and releases heat, is all applicable to oxygen-eliminating device safe retrieving under making the hydrophobic enthalpy of startup be reduced to various start operating performance.The double control logic of unit DCS (dcs) to high-pressure heater of particular design ensure that each high-pressure heater, under 2 kinds of different working modes, all can complete the heat regenerative system mode of operation that Once-through Boiler starts the cold end loss of overall process and minimizing power station thermodynamic cycle safely, economically.

The present invention is better than there is the direct current furnace starting system starting boiler water circulating pump to the recovering effect of working medium and heat between the power station supercritical DC furnace starting period.

The present invention is applicable to the power station supercritical double-reheat boiler start-up system designing a new generation, when high-pressure heater and the bid of oxygen-eliminating device system, meet the aforementioned additional through-flow requirement being used as water water heat exchanger, a lot of expense can not be increased, but significantly can reduce boiler island investment.

Benefit of the present invention is adopted to be:

● cold start, warm starting, hot starting, hot start, very hot startup all can reclaim working medium in the supercritical double-reheat boiler startup process of power station and heat comprehensively, and recovering effect is better than there is the direct current furnace starting system starting boiler water circulating pump.

● from ignition of the boiler, water-cooling wall crosses expansion until minimal once-through circulation load all can reclaim working medium in the supercritical DC furnace start-up course of power station and heat comprehensively, and recovering effect is better than there is the direct current furnace starting system starting boiler water circulating pump.

● without starting boiler water circulating pump and subsystem thereof, significantly reducing capital expenditure, eliminating import and relying on.

● without starting boiler water circulating pump, save station service.

● without starting boiler water circulating pump, maintenance, maintenance workload is little, and it is low to possess expense.

● without steam-water separator water storage tank to separator water level control valve pipeline thermal back-up system, save stand-by heat system energy consumption.

● run simply, safely, reliably, operating cost is low.

● without iron pollution.

● the operting differential pressure of separator water level control valve is little, without serious cavitation, significantly reduces cost.

(4) accompanying drawing illustrates:

Fig. 1 has the direct current furnace starting system structure chart starting boiler water circulating pump atmospheric drainage flash tank drainage pump

The each subsystem starting boiler water circulating pump and need is not drawn, to avoid system construction drawing too numerous and diverse in Fig. 1.

Fig. 1 illustrates the direct current furnace starting system structure chart starting boiler water circulating pump atmospheric drainage flash tank drainage pump for single reheat unit, do not draw ultra-high pressure cylinder and secondary low-temperature reheater, secondary high-temperature reheater.

Start boiler water circulating pump (8) in Once-through Boiler start-up course, to sucking the hydrophobic supercharging of startup starting boiler water circulating pump (8), reclaim working medium and heat through starting boiler water circulating pump outlet valve (9) press-in economizer (5); Start from Once-through Boiler igniting, have an appointment always 20% startup flow be admitted to atmospheric drainage flash tank (33), make separator water level control valve (31) and the maintenance of corresponding pipeline hot, exempt from excessive thermal shock; A few minutes of the phase of expansion are crossed at water-cooling wall, start increment that pulsed cannot occur by boiler water circulating pump (8) to start and hydrophobicly send economizer (5) back to, open large separator water level control valve (31) and open water storage tank drain valve (32) and increment is started hydrophobic feeding atmospheric drainage flash tank (33) and water level in steam-water separator (6) can be controlled in normal range (NR).The startup sending into atmospheric drainage flash tank (33) is hydrophobic, if water quality is qualified, via drain tank (34), drainage pump (35), start drain recovery valve (21) and be recovered to condenser (25) but often due to serious iron pollution, working medium should not reclaim, thermal loss, defectively hydrophobicly enters trench through blowoff valve (27).

For being easier to understand the function of direct current furnace starting system, the main portion cover not only depicting direct current furnace starting system in FIG also briefly depicts main portion's cover high temperature superheater (1) of Once-through Boiler body, pendant superheater (2), low temperature superheater (3), water-cooling wall (4), a high temperature reheater (10), main portion's cover high pressure cylinder (17) of part of a low-temperature reheater (11) and steam turbine and accessory system thereof, high-pressure main throttle valve (16), high pressure bypass valve (13), intermediate pressure cylinder (20), reheat stop interceptor valve (19), low pressure (LP) cylinder (24), low voltage bypass valve (23), condenser (25), condensate pump (26), low-pressure heater (28).High-pressure heater (12) is a kind of simplification expression, and practical double reheat power generation sets high-pressure heater system is composed in series by 4 usually; Height adds admission non-return valve (29) and height, and to add admission stop valve (30) be coordinate this simplification expression accompanying drawing number.Low-pressure heater (28) is a kind of expression more simplified, and practical low-pressure heater system is composed in series by 4 usually; The admission of low-pressure heater (28) and to be hydrophobicly all simplified.

Fig. 2 has the direct current furnace starting system structure chart starting the hydrophobic in line condenser of boiler water circulating pump startup

The each subsystem starting boiler water circulating pump and need is not drawn, to avoid system construction drawing too numerous and diverse in Fig. 2.

Fig. 2 illustrates for single reheat unit and starts the direct current furnace starting system structure chart that boiler water circulating pump starts hydrophobic in line condenser, does not draw ultra-high pressure cylinder and secondary low-temperature reheater, secondary high-temperature reheater.

Start boiler water circulating pump (8) in Once-through Boiler start-up course, to sucking the hydrophobic supercharging of startup starting boiler water circulating pump (8), reclaim working medium and heat through starting boiler water circulating pump outlet valve (9) press-in economizer (5); From Once-through Boiler igniting start to have an appointment always 20% startup flow be admitted to condenser (25), make separator water level control valve (31) and the maintenance of corresponding pipeline valve hot, exempt from excessive thermal shock; A few minutes of the phase of expansion are crossed at water-cooling wall, start increment that pulsed cannot occur by boiler water circulating pump (8) to start and hydrophobicly send economizer (5) back to, open large separator water level control valve (31) and startup drain recovery valve (21) and enter condenser (25) through Backpack type temperature-decreased pressure reducer (54) and water level in steam-water separator (6) can be controlled in normal range (NR).The startup of all feeding condensers (25) is hydrophobic is all reclaimed but thermal loss as working medium.

For being easier to understand the function of direct current furnace starting system, the main portion cover not only depicting direct current furnace starting system in fig. 2 also briefly depicts main portion's cover high temperature superheater (1) of Once-through Boiler body, pendant superheater (2), low temperature superheater (3), water-cooling wall (4), a high temperature reheater (10), main portion's cover high pressure cylinder (17) of part of a low-temperature reheater (11) and steam turbine and accessory system thereof, high-pressure main throttle valve (16), high pressure bypass valve (13), intermediate pressure cylinder (20), reheat stop interceptor valve (19), low pressure (LP) cylinder (24), low voltage bypass valve (23), condenser (25), condensate pump (26), low-pressure heater (28).High-pressure heater (12) is a kind of simplification expression, and practical double reheat power generation sets high-pressure heater system is composed in series by 4 usually; Height adds admission non-return valve (29) and height, and to add admission stop valve (30) be coordinate this simplification expression accompanying drawing number.Low-pressure heater (28) is a kind of expression more simplified, and practical low-pressure heater system is composed in series by 4 usually; The admission of low-pressure heater (28) and to be hydrophobicly all simplified.

Fig. 3 has the direct current furnace starting system structure chart of atmospheric drainage flash tank drainage pump without starting boiler water circulating pump

Fig. 3 illustrates the direct current furnace starting system structure chart having atmospheric drainage flash tank drainage pump without startup boiler water circulating pump for single reheat unit, do not draw ultra-high pressure cylinder and secondary low-temperature reheater, secondary high-temperature reheater.

In the whole start-up course of Once-through Boiler, comprise a few minutes of crossing the phase of expansion, the water level in steam-water separator (6) is combined by water storage tank water level bypass valve (18), separator water level control valve (31) and water storage tank drain valve (32) and regulates; Start and hydrophobicly enter oxygen-eliminating device (22) partial heat via water storage tank water level bypass valve (18) and can reclaim, enter atmospheric drainage flash tank (33) part through separator water level control valve (31) and water storage tank drain valve (32) and start hydrophobic not only thermal loss, because serious iron pollution also should not reclaim working medium.

For being easier to understand the function of direct current furnace starting system, the main portion cover not only depicting direct current furnace starting system in figure 3 also briefly depicts main portion's cover high temperature superheater (1) of Once-through Boiler body, pendant superheater (2), low temperature superheater (3), water-cooling wall (4), a high temperature reheater (10), main portion's cover high pressure cylinder (17) of part of a low-temperature reheater (11) and steam turbine and accessory system thereof, high-pressure main throttle valve (16), high pressure bypass valve (13), intermediate pressure cylinder (20), reheat stop interceptor valve (19), low pressure (LP) cylinder (24), low voltage bypass valve (23), condenser (25), condensate pump (26), low-pressure heater (28).High-pressure heater (12) is a kind of simplification expression, and practical high-pressure heater system is composed in series by 3 usually; Height adds admission non-return valve (29) and height, and to add admission stop valve (30) be coordinate this simplification expression accompanying drawing number.Low-pressure heater (28) is a kind of expression more simplified, and practical low-pressure heater system is composed in series by 4 usually; The admission of low-pressure heater (28) and to be hydrophobicly all simplified.

Fig. 4 starts the direct current furnace starting system structure chart of hydrophobic in line condenser without starting boiler water circulating pump

Fig. 4 illustrates the direct current furnace starting system structure chart without starting the hydrophobic in line condenser of boiler water circulating pump startup for single reheat unit, does not draw ultra-high pressure cylinder and secondary low-temperature reheater, secondary high-temperature reheater.

In the whole start-up course of Once-through Boiler, comprise a few minutes of crossing the phase of expansion, water level in steam-water separator (6) is controlled by separator water level control valve (31), start hydrophobic through start drain recovery valve (21) and Backpack type temperature-decreased pressure reducer (54) condenser (25) recovery, start hydrophobic thermal loss.

For being easier to understand the function of direct current furnace starting system, the main portion cover not only depicting direct current furnace starting system in the diagram also briefly depicts main portion's cover high temperature superheater (1) of Once-through Boiler body, pendant superheater (2), low temperature superheater (3), water-cooling wall (4), a high temperature reheater (10), main portion's cover high pressure cylinder (17) of part of a low-temperature reheater (11) and steam turbine and accessory system thereof, high-pressure main throttle valve (16), high pressure bypass valve (13), intermediate pressure cylinder (20), reheat stop interceptor valve (19), low pressure (LP) cylinder (24), low voltage bypass valve (23), condenser (25), condensate pump (26), low-pressure heater (28).High-pressure heater (12) is a kind of simplification expression, and practical high-pressure heater system is composed in series by 3 usually; Height adds admission non-return valve (29) and height, and to add admission stop valve (30) be coordinate this simplification expression accompanying drawing number.Low-pressure heater (28) is a kind of expression more simplified, and practical low-pressure heater system is composed in series by 4 usually; The admission of low-pressure heater (28) and to be hydrophobicly all simplified.

Fig. 5 high-pressure heater reclaims the method structure chart of the hydrophobic working medium of double reheat boiler startup and heat

Core knowledge property right of the present invention between the Once-through Boiler starting period, introduces No. 1 high-pressure heater (44) of steamer pusher side, No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) as water water heat exchanger, by hydrophobic for the startup of the high enthalpy temperature being cooled to oxygen-eliminating device (22) to accept safely, reclaim working medium and heat comprehensively.One of the heat reclaimed is made up of 2 parts, the startup of high enthalpy is hydrophobic to be absorbed by high-pressure feed water through water water heat exchanger liberated heat; Two, the hydrophobic heat that carries in a mixed manner of the startup slightly higher than deaerator storage tank water storage temperature enters oxygen-eliminating device.

Steam-water separator water storage tank (7) startup is out hydrophobic through water storage tank outlet shutoff valve (53), separator water level control valve (31) enters the shell-side of No. 1 high-pressure heater (44), after cooling, through No. 1 HP heater drainage control valve (48), enter the shell-side of No. 2 high-pressure heaters (45), after cooling, through No. 2 HP heater drainage control valves (49), enter the shell-side of No. 3 high-pressure heaters (46), after cooling, through No. 3 HP heater drainage control valves (50), enter the shell-side of No. 4 high-pressure heaters (47), after cooling, oxygen-eliminating device (22) is entered through No. 4 HP heater drainage control valves (51).Feed pump (15) sucks low pressure feed water from oxygen-eliminating device (22), high-pressure feed water is become after supercharging, through feed pump outlet valve (14), flow through the pipe side of No. 4 high-pressure heaters (47), No. 3 high-pressure heaters (46), No. 2 high-pressure heaters (45), No. 1 high-pressure heater (44) successively, enter economizer (5) after cascade raising temperature, complete comprehensive recovery of working medium and heat.

After power station supercritical DC furnace reaches minimal once-through circulation load, steam-water separator (6) is micro-superheat state in dry state, the water level of steam-water separator water storage tank (7) is to 0, separator water level control valve (31) complete shut-down, No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valve (51) complete shut-downs, continue to close water storage tank outlet shutoff valve (53) afterwards in 120 seconds; DCS (dcs) recovers the water lev el control pattern to No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51); Open successively No. 4 high add admission stop valve (43), No. 3 high add admission stop valve (42), No. 2 high add admission stop valve (41), No. 1 highly add admission stop valve (40); No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) return the heat regenerative system method of operation.

For being easier to understand the function of direct current furnace starting system, the main portion cover not only depicting direct current furnace starting system in Figure 5 also briefly depicts main portion's cover high temperature superheater (1) of Once-through Boiler body, pendant superheater (2), low temperature superheater (3), water-cooling wall (4), a high temperature reheater (10), a low-temperature reheater (11), secondary high-temperature reheater (58), main portion's cover ultra-high pressure cylinder (56) of part of secondary low-temperature reheater (59) and steam turbine and accessory system thereof, high pressure cylinder (17), super-pressure main inlet throttle-stop valve (55), single reheat combined emergency stop and governing valve (60), double reheat combined emergency stop and governing valve (61), super-pressure bypass valve (57), high pressure bypass valve (13), intermediate pressure cylinder (20), low pressure (LP) cylinder (24), low voltage bypass valve (23), condenser (25), condensate pump (26), low-pressure heater (28).

4 high-pressure heaters and related valve, give new figure and Reference numeral.

Do not draw unit DCS (dcs) in Figure 5 in order to avoid figure is too complicated.

Reference numeral in Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5:

1 high temperature superheater, 2 pendant superheaters, 3 low temperature superheaters,

4 water-cooling walls, 5 economizers, 6 steam-water separators,

7 steam-water separator water storage tanks, 8 start boiler water circulating pumps, 9 start boiler water circulating pump outlet valves,

10 high temperature reheaters, 11 low-temperature reheaters, 12 high-pressure heaters,

13 high pressure bypass valves, 14 feed pump outlet valves, 15 feed pumps,

16 high-pressure main throttle valve, 17 high pressure cylinders, 18 separator water level bypass valves,

19 reheat stop interceptor valves, 20 intermediate pressure cylinders, 21 start drain recovery valves,

22 oxygen-eliminating devices, 23 low voltage bypass valves, 24 low pressure (LP) cylinders,

25 condensers, 26 condensate pumps, 27 blowoff valves,

28 low-pressure heaters, 29 height add admission non-return valve, 30 height add admission stop valve,

31 separator water level control valves, 32 water storage tank drain valves, 33 atmospheric drainage flash tanks,

34 drain tanks, 35 drainage pumps, No. 361 high add admission non-return valve,

No. 372 high add admission non-return valve, No. 383 high add admission non-return valve, No. 394 high add admission non-return valve,

No. 401 high add admission stop valve, No. 412 high add admission stop valve, No. 423 high add admission stop valve,

No. 434 high add admission stop valve, No. 441 high-pressure heaters, No. 452 high-pressure heaters,

No. 463 high-pressure heaters, No. 474 high-pressure heaters, No. 481 HP heater drainage control valves,

No. 492 HP heater drainage control valves, No. 503 HP heater drainage control valves, No. 514 HP heater drainage control valves,

52 oxygen-eliminating device decompression exhaust steam valves, 53 water storage tank outlet shutoff valves, 54 Backpack type temperature-decreased pressure reducers,

55 super-pressure stop valves, 56 ultra-high pressure cylinders, 57 super-pressure bypass valves,

58 secondary high-temperature reheaters, 59 2 low-temperature reheaters, 60 single reheat combined emergency stop and governing valves,

61 double reheat combined emergency stop and governing valves.

(5) detailed description of the invention:

Below for the power station supercritical double-reheat boiler of a 1000MW grade, composition graphs 5, further illustrates the method that high-pressure heater of the present invention reclaims the hydrophobic working medium of double reheat boiler startup and heat:

The method that high-pressure heater of the present invention reclaims the hydrophobic working medium of double reheat boiler startup and heat comprises steam-water separator (6), steam-water separator water storage tank (7), water storage tank outlet shutoff valve (53), separator water level control valve (31), No. 1 high adds admission stop valve (40), No. 2 high adds admission stop valve (41), No. 3 high adds admission stop valve (42), No. 4 high adds admission stop valve (43), No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 3 high-pressure heaters (47), No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51), oxygen-eliminating device (22), oxygen-eliminating device decompression exhaust steam valve (52) and unit DCS (dcs).

Check and revise the flow area of the import of drawing gas of No. 1 high-pressure heater (44) and the Kv value of separator water level control valve (31), the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, steam-water separator (6) is no more than 1.0MPa with the pressure reduction of No. 1 high-pressure heater (44) shell-side.Check that the draw gas strike plate of import of confirmation No. 1 high-pressure heater (44) is enough to bear the hydrophobic impact of boiler startup, U-tube group can not be damaged, if desired reinforcement strike plate.Check and revise the HP heater drainage inlet flow area of the hydrophobic outlet flow area of No. 1 high-pressure heater (44), the Kv value of No. 1 HP heater drainage control valve (48) and No. 2 high-pressure heaters (45), the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 1 high-pressure heater (44) is not higher than 8MPa; Check and revise the hydrophobic outlet flow area of No. 2 high-pressure heaters (45), the business of the Kv value of No. 2 HP heater drainage control valves (49) and No. 3 high-pressure heaters (46) adds hydrophobic inlet flow area, the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 2 high-pressure heaters (45) is not higher than 5.4MPa; Check and revise the HP heater drainage inlet flow area of the hydrophobic outlet flow area of No. 3 high-pressure heaters (46), the Kv value of No. 3 HP heater drainage control valves (50) and No. 4 high-pressure heaters (47), the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 3 high-pressure heaters (46) is not higher than 3.4MPa; Check and revise the HP heater drainage inlet flow area of the hydrophobic outlet flow area of No. 4 high-pressure heaters (47), the Kv value of No. 4 HP heater drainage control valves (51) and oxygen-eliminating device (22), the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 4 high-pressure heaters (47) is not higher than 2.3MPa.No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) such as to be at hundred parts of ratio characteristics.

When cold start, warm starting, hot starting, hot start, very hot startup, steam-water separator pressure gets 6MPa to 9MPa respectively, and lower value is got in cold start, and very hot startup gets high value, and warm starting, hot starting, hot start get median; In start-up course, steam-water separator pressure can use aperture and the fuel regulation of high and low pressure bypass valve.

Between the Once-through Boiler starting period, No. 1 high adds admission stop valve (40), No. 2 highly add admission stop valve (41), No. 3 highly add admission stop valve (42), No. 4 high admission stop valves (43) that add all are in close stance, and shell-side and the turbine steam extraction system of the shell-side of No. 1 high-pressure heater (44), the shell-side of No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) are reliably isolated.

Steam-water separator water storage tank (7) startup is out hydrophobic through water storage tank outlet shutoff valve (53), separator water level control valve (31) enters the shell-side of No. 1 high-pressure heater (44), after cooling, through No. 1 HP heater drainage control valve (48) decompression, enter the shell-side of No. 2 high-pressure heaters (45), after cooling, through No. 2 HP heater drainage control valve (49) decompressions, enter the shell-side of No. 3 high-pressure heaters (46), after cooling, through No. 3 HP heater drainage control valve (50) decompressions, enter, the shell-side of No. 4 high-pressure heaters (47), after cooling, through No. 4 HP heater drainage control valve (51) decompressions, enter oxygen-eliminating device (22), feed pump (15) sucks low pressure feed water from oxygen-eliminating device (22), high-pressure feed water is become after supercharging, through feed pump outlet valve (14), flow through the pipe side of No. 4 high-pressure heaters (47), No. 3 high-pressure heaters (46), No. 2 high-pressure heaters (45), No. 1 high-pressure heater (44) successively, enter economizer (5) after cascade raising temperature, complete comprehensive recovery of working medium and heat.

When the large discharge that very hot startup water-cooling wall crosses expansion starts hydrophobic passing through, No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valve (51) standard-sized sheets, oxygen-eliminating device (22), with the low enthalpy condensate water of stepping, controls the pressure of oxygen-eliminating device (22) not higher than 1.5MPa.

Water storage tank outlet shutoff valve (53) has the ability of reliable isolation supercritical pressure, is provided with pressure sensor and observable drain valve to confirm that water storage tank outlet shutoff valve (53) is closed tightly between water storage tank outlet shutoff valve (53) and separator water level control valve (31).The condition that water storage tank outlet shutoff valve (53) is opened is: steam-water separator pressure is not higher than 9.0MPa; No. 1 high adds admission stop valve (40), No. 2 highly add admission stop valve (41), No. 3 highly add admission stop valve (42), No. 4 high admission stop valves (43) that add all are closed tightly; No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) are all positioned at the initial opening amount region of aperture 70% to 80%; Unit DCS (dcs) enters water water heat exchanger control model; Feed pump (15) is working properly, and position left by feed pump outlet valve (14); Above condition meets simultaneously, with logic.

Separator water level control valve (31) is a cage spool control valve, and wait hundred parts of ratio characteristics, shell can bear supercritical pressure, and its Kv value should ensure the large discharge that can be crossed expansion when inlet outlet pressure differential is 0.5MPa by very hot startup water-cooling wall.

Oxygen-eliminating device (22) is built-in deaerator, the highest permission operating pressure 2.0MPa, and Steam Turbine at full capacity oxygen-eliminating device operating pressure is no more than 1.3MPa, Once-through Boiler when very hot startup oxygen-eliminating device pressure not higher than 1.5MPa; Oxygen-eliminating device (22) is provided with oxygen-eliminating device decompression exhaust steam valve (52), and when oxygen-eliminating device pressure is opened fast higher than during 1.5MPa, steam enters the low voltage bypass entrance of condenser (25); When oxygen-eliminating device pressure returns to 1.0MPa, oxygen-eliminating device decompression exhaust steam valve (52) cuts out automatically.Oxygen-eliminating device decompression exhaust steam valve (52) when opening oxygen-eliminating device decompression exhaust steam valve (52) outlet pressure be no more than 0.7MPa, the built-in energy dissipator of condenser (25) can accept safely; Oxygen-eliminating device decompression exhaust steam valve (52) relieving capacity when inlet pressure 1.5MPa is 0.0755MCR mass flow.

Unit DCS (dcs) cooperation control steam-water separator (6), steam-water separator water storage tank (7), water storage tank outlet shutoff valve (53), separator water level control valve (31), No. 1 high adds admission stop valve (40), No. 2 high adds admission stop valve (41), No. 3 high adds admission stop valve (42), No. 4 high adds admission stop valve (43), No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47), No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51), oxygen-eliminating device (22), oxygen-eliminating device decompression exhaust steam valve (52) safety, complete Once-through Boiler start-up course economically.After completing start-up course, unit DCS closes water storage tank outlet shutoff valve (53) and reliably isolates steam-water separator water storage tank (7) and No. 1 high-pressure heater (44) shell-side, and unit DCS recovers high-pressure heater heat regenerative system mode and runs.

Once-through Boiler underrun and furnace shutting down process are the inverse process that Once-through Boiler starts.When the downhill race of Once-through Boiler load is to minimal once-through circulation load, the pressure downhill race of steam-water separator (6) is to 9MPa or lower, No. 1, tight closing is high add admission stop valve (40), No. 2 high add admission stop valve (41), No. 3 high add admission stop valve (42), No. 4 highly add admission stop valve (43), make No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) exit heat regenerative system state, unit DCS (dcs) is switched to water water heat exchanger control logic, DCS instruction No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) are all positioned at the initial opening amount region of aperture 70% to 80%, when visible water-level appears in steam-water separator (6), open water storage tank outlet shutoff valve (53) and control at DCS the water level regulating steam-water separator (6) by separator water level control valve (31), DCS cooperation control No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), the aperture of No. 4 HP heater drainage control valves (51), make No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), the shell pressure of No. 4 high-pressure heaters (47) is in respective desired value, blowing out is hydrophobic through water storage tank outlet shutoff valve (53), separator water level control valve (31) enters the shell-side of No. 1 high-pressure heater (44), after cooling, through No. 1 HP heater drainage control valve (48) decompression, enter the shell-side of No. 2 high-pressure heaters (45), after cooling, through No. 2 HP heater drainage control valve (49) decompressions, enter the shell-side of No. 3 high-pressure heaters (46), after cooling, through No. 3 HP heater drainage control valve (50) decompressions, enter, the shell-side of No. 4 high-pressure heaters (47), after cooling, through No. 4 HP heater drainage control valve (51) decompressions, enter oxygen-eliminating device (22), feed pump (15) sucks low pressure feed water from oxygen-eliminating device (22), high-pressure feed water is become after supercharging, through feed pump outlet valve (14), flow through the pipe side of No. 4 high-pressure heaters (47), No. 3 high-pressure heaters (46), No. 2 high-pressure heaters (45), No. 1 high-pressure heater (44) successively, enter economizer (5) after cascade raising temperature, complete comprehensive recovery of working medium and heat.

The hydrophobic amount of furnace shutdown period blowing out is quite less than confluent, and the pressure of oxygen-eliminating device (22) glides, safer compared with start operating performance.

Claims

1. the method for the high-pressure heater recovery hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that: the present invention includes steam-water separator (6), steam-water separator water storage tank (7), water storage tank outlet shutoff valve (53), separator water level control valve (31), No. 1 high adds admission stop valve (40), No. 2 high adds admission stop valve (41), No. 3 high adds admission stop valve (42), No. 4 high adds admission stop valve (43), No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47), No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51), oxygen-eliminating device (22), oxygen-eliminating device decompression exhaust steam valve (52) and unit DCS (dcs), between the Once-through Boiler starting period, No. 1 high adds admission stop valve (40), No. 2 highly add admission stop valve (41), No. 3 highly add admission stop valve (42), No. 4 high admission stop valves (43) that add all are in close stance, and shell-side and the turbine steam extraction system of the shell-side of No. 1 high-pressure heater (44), the shell-side of No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) are reliably isolated, steam-water separator water storage tank (7) startup is out hydrophobic through water storage tank outlet shutoff valve (53), separator water level control valve (31) enters the shell-side of No. 1 high-pressure heater (44), after cooling, through No. 1 HP heater drainage control valve (48) decompression, enter the shell-side of No. 2 high-pressure heaters (45), after cooling, through No. 2 HP heater drainage control valve (49) decompressions, enter the shell-side of No. 3 high-pressure heaters (46), after cooling, through No. 3 HP heater drainage control valve (50) decompressions, enter, the shell-side of No. 4 high-pressure heaters (47), after cooling, through No. 4 HP heater drainage control valve (51) decompressions, enter oxygen-eliminating device (22), the control logic of outlet drain regulating valve when high-pressure heater is used as water water heat exchanger of high-pressure heater is completely different as control logic during heat regenerative system from high-pressure heater, unit DCS (dcs) must have the different control logic of 2 covers, switches in good time, when high-pressure heater is used as water water heat exchanger, the outlet drain regulating valve of No. 1 high-pressure heater is for controlling the pressure differential between No. 1 high-pressure heater shell-side and No. 2 high-pressure heater shell-sides, the outlet drain regulating valve of No. 2 high-pressure heaters is for controlling the pressure differential between No. 2 high-pressure heater shell-sides and No. 3 high-pressure heater shell-sides, the outlet drain regulating valve of No. 3 high-pressure heaters is for controlling the pressure differential between No. 3 high-pressure heater shell-sides and No. 4 high-pressure heater shell-sides, the outlet drain regulating valve of No. 4 high-pressure heaters is for controlling the pressure differential between No. 4 high-pressure heater shell-sides and oxygen-eliminating device, the adjustment target being governor motion with the outlet drain regulating valve of each high-pressure heater is the shell pressure of each corresponding high-pressure heater, regulate desired value and instant oxygen-eliminating device pressure, steam-water separator pressure relevant, the shell pressure desired value of No. 1 high-pressure heater is that steam-water separator pressure subtracts 1.0MPa, and the shell pressure desired value of No. 4 high-pressure heaters is that oxygen-eliminating device pressure adds 1.0MPa, the shell pressure desired value of No. 2 high-pressure heaters be No. 3 high-pressure heater shell pressures add No. 1 high-pressure heater of 0.54 times and No. 4 high-pressure heater shell pressures poor, the shell pressure desired value of No. 3 high-pressure heaters be No. 4 high-pressure heater shell pressures add No. 1 high-pressure heater of 0.2 times and No. 4 high-pressure heater shell pressures poor, feed pump (15) sucks low pressure feed water from oxygen-eliminating device (22), high-pressure feed water is become after supercharging, through feed pump outlet valve (14), flow through the pipe side of No. 4 high-pressure heaters (47), No. 3 high-pressure heaters (46), No. 2 high-pressure heaters (45), No. 1 high-pressure heater (44) successively, enter economizer (5) after cascade raising temperature, complete comprehensive recovery of working medium and heat, when the large discharge that very hot startup water-cooling wall crosses expansion starts hydrophobic passing through, No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valve (51) standard-sized sheets, oxygen-eliminating device (22), with the low enthalpy condensate water of stepping, controls the pressure of oxygen-eliminating device (22) not higher than 1.5MPa.

2. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that described water storage tank outlet shutoff valve (53) has the ability of reliable isolation supercritical pressure, be provided with pressure sensor and observable drain valve between water storage tank outlet shutoff valve (53) and separator water level control valve (31) to confirm that water storage tank outlet shutoff valve (53) is closed tightly; The condition that water storage tank outlet shutoff valve (53) is opened is: steam-water separator pressure is not higher than 9.0MPa; No. 1 high adds admission stop valve (40), No. 2 highly add admission stop valve (41), No. 3 highly add admission stop valve (42), No. 4 high admission stop valves (43) that add all are closed tightly; No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) are all positioned at the initial opening amount region of aperture 70% to 80%; Unit DCS (dcs) enters water water heat exchanger control model; Feed pump (15) is working properly, and position left by feed pump outlet valve (14); Above condition meets simultaneously, with logic.

3. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that described separator water level control valve (31) is a cage spool control valve, Deng hundred parts of ratio characteristics, shell can bear supercritical pressure, and its Kv value should ensure the large discharge that can be crossed expansion when inlet outlet pressure differential is 0.5MPa by very hot startup water-cooling wall.

4. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that the draw gas strike plate of import of No. 1 described high-pressure heater (44) is enough to bear the hydrophobic impact of boiler startup, U-tube group can not be damaged; The HP heater drainage inlet flow area of the hydrophobic outlet flow area of No. 1 high-pressure heater (44), the Kv value of No. 1 HP heater drainage control valve (48) and No. 2 high-pressure heaters (45), the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 1 high-pressure heater (44) is not higher than 8MPa.

5. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that the HP heater drainage inlet flow area of the hydrophobic outlet flow area of No. 2 described high-pressure heaters (45), the Kv value of No. 2 HP heater drainage control valves (49) and No. 3 high-pressure heaters (46), the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 2 high-pressure heaters (45) is not higher than 5.4MPa.

6. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that the HP heater drainage inlet flow area of the hydrophobic outlet flow area of No. 3 described high-pressure heaters (46), the Kv value of No. 3 HP heater drainage control valves (50) and No. 4 high-pressure heaters (47), the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 3 high-pressure heaters (46) is not higher than 3.4MPa.

7. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that the HP heater drainage inlet flow area of the hydrophobic outlet flow area of No. 4 described high-pressure heaters (47), the Kv value of No. 4 HP heater drainage control valves (51) and oxygen-eliminating device (22), the large discharge guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 4 high-pressure heaters (47) is not higher than 2.3MPa.

8. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that described oxygen-eliminating device (22) is built-in deaerator, the highest permission operating pressure 2.0MPa, Steam Turbine at full capacity oxygen-eliminating device operating pressure is no more than 1.3MPa, Once-through Boiler when very hot startup oxygen-eliminating device pressure not higher than 1.5MPa.

9. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that described oxygen-eliminating device (22) is provided with oxygen-eliminating device decompression exhaust steam valve (52), when oxygen-eliminating device pressure is opened fast higher than during 1.5MPa, steam enters the low voltage bypass entrance of condenser (25); When oxygen-eliminating device pressure returns to 1.0MPa, oxygen-eliminating device decompression exhaust steam valve (52) cuts out automatically; Oxygen-eliminating device decompression exhaust steam valve (52) when opening oxygen-eliminating device decompression exhaust steam valve (52) outlet pressure be no more than 0.7MPa, the built-in energy dissipator of condenser (25) can accept safely; Oxygen-eliminating device decompression exhaust steam valve (52) relieving capacity when inlet pressure 1.5MPa is 0.075BMCR mass flow.

10. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that described unit DCS dcs cooperation control steam-water separator (6), steam-water separator water storage tank (7), water storage tank outlet shutoff valve (53), separator water level control valve (31), No. 1 high adds admission stop valve (40), No. 2 high adds admission stop valve (41), No. 3 high adds admission stop valve (42), No. 4 high adds admission stop valve (43), No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47), No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51), oxygen-eliminating device (22), oxygen-eliminating device decompression exhaust steam valve (52) safety, complete Once-through Boiler start-up course economically, the aperture of DCS cooperation control No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51), make No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) shell pressure in respective desired value, after completing start-up course, unit DCS closes water storage tank outlet shutoff valve (53) and reliably isolates steam-water separator water storage tank (7) and No. 1 high-pressure heater (44) shell-side, and unit DCS recovers high-pressure heater heat regenerative system mode and runs.