It is a kind of that heat pressing type extra-supercritical unit zero is high adds and switched system
Technical field
The present invention relates to power plant back heating system.Especially relate to that a kind of heat pressing type extra-supercritical unit zero is high adds and switched system.
Background technology
In recent years, China's fired power generating unit annual utilizes hourage persistently to reduce, most of unit load rates are less than 70%, and under low loading conditions, the heat-economy of unit and safety to be decreased obviously, therefore consider that the heat regenerative system from current power plant is commonly used improves, to improve the heat-economy of unit under low load condition.From thermodynamics analysis, the backheat progression of unit is the most, and its thermal efficiency is the highest, but in view of factors such as steam turbine structures, backheat progression also receives certain restriction, at present frequently with for 7-9 level backheat.The Chinese patent of Application No. 201210047719.1 discloses a kind of heat regenerative system using jet type heat pump, on the basis of the existing backheat of unit, it is provided with jet type heat pump between the bleed steam pipework of adjacent double-bank heater, the next stage relatively low by the injection pressure that draws gas utilizing pressure higher draws gas, the mixed vapour produced enters heat-setting water in the bleeder heater newly increased, the irreversible loss in heat recovery process is reduced with this, but this patent is only to consider to improve the thermal efficiency of unit by increasing backheat progression, and when not taking into account high underload in the case of regenerative steam pressure at different levels reduce, boiler feed temperature is on the low side, gap is still had under the conditions of its heat consumption relatively rated load;Furnace side aspect is low due to feed temperature, and economizer exit cigarette temperature also can be on the low side, directly results in denitration efficiency and declines.
Prior art is primarily present problems with:
1, unit efficiency design load to be less than under low load condition;
2, under low load condition, economizer exit cigarette temperature is on the low side, it is impossible to ensure denitration efficiency.
Summary of the invention
In order to solve the problems referred to above, invent the high switched system added of a kind of heat pressing type extra-supercritical unit zero, this system mainly comprises boiler (1), steam turbine high-pressure cylinder (2), Steam Turbine Through IP Admission (3), No. 0, No. 1, No. 2, No. 3 high-pressure heaters (4, 5, 6, 7), oxygen-eliminating device (8), hot press (9) and feed pump (10) and connect the valves and fittings of relevant apparatus, main valve has: hot press high-pressure side intake valve (11), hot press low-pressure side intake valve (12), hot press air bleeding valve (13), No. 0 high-pressure heater water side outlet electrodynamic valve (14), No. 0 high-pressure heater water side entrance electrodynamic valve (15), No. 0 hydrophobic electrodynamic valve of high-pressure heater (16), No. 0 high-pressure heater water side bypass electrodynamic valve (17).
At height when system is run, can switch under low load condition: in the case of high load capacity, hot press high-pressure side intake valve (11), hot press low-pressure side intake valve (12), hot press air bleeding valve (13), No. 0 high-pressure heater water side outlet electrodynamic valve (14), No. 0 high-pressure heater water side entrance electrodynamic valve (15), No. 0 hydrophobic electrodynamic valve of high-pressure heater (16) is turned off, open No. 0 high-pressure heater water side bypass electrodynamic valve (17), No. 0 high adding system does not puts into operation, No. 1 high-pressure heater water outlet is directly entered unit heat vapo(u)rization system;Under low load condition, hot press high-pressure side intake valve, hot press low-pressure side intake valve, hot press air bleeding valve, No. 0 high-pressure heater water side outlet electrodynamic valve, No. 0 high-pressure heater water side entrance electrodynamic valve, No. 0 hydrophobic electrodynamic valve of high-pressure heater is all opened, close No. 0 high-pressure heater water side bypass electrodynamic valve, No. 0 high-pressure heater puts into operation, No. 1 high-pressure heater water outlet enters the heating evaporation system entering back into original system after No. 0 high-pressure heater continues heating, to improve the feed temperature of boiler under low load condition.
System run time hot press power steam take from boiler main steam, the steam being sucked can connect from original system 1 section draw gas (asAccompanying drawing 1) or 2 sections draw gas (asAccompanying drawing 2), mixed vapour after coupling enters No. 0 high-pressure heater heating boiler feed water, and it is hydrophobic flows automatically to No. 1 high-pressure heater, hydrophobic heat, measures further recovery.
In this system, No. 0 high-pressure heater is hydrophobic flows automatically to No. 1 high-pressure heater, if Reconstruction in field does not satisfies the requirements, No. 0 HP heater drainage also can be directly discharged to oxygen-eliminating device, but relatively the former economy decreases.
Referring now to prior art, the advantage of the application is:
1, by increasing No. zero high switched system that adds, improve unit feed temperature under low loading conditions, thus significantly improve the economy of unit variable parameter operation;
2, effectively reduce economizer exit cigarette temperature, advantageously ensure that the properly functioning of denitrating system;
3, height can be alleviated to a certain extent and add excision to unit heat economy and the impact of boiler safety.
Accompanying drawing explanation
Next will be in conjunction withAccompanying drawingThe application is further explained, wherein:
Figure 1: the heat pressing type extra-supercritical unit of the present invention zero is high to be added and the embodiment one of switched system;
Figure 2: the heat pressing type extra-supercritical unit of the present invention zero is high to be added and the embodiment two of switched system;
In figure:
1-boiler,
2-steam turbine high-pressure cylinder,
3-Steam Turbine Through IP Admission,
No. zero high-pressure heater of 4-,
5-1 high-pressure heater,
6-2 high-pressure heater,
7-3 high-pressure heater,
8-oxygen-eliminating device,
9-hot press,
10-feed pump,
11-hot press high-pressure side intake valve,
12-hot press low-pressure side intake valve,
13-hot press air bleeding valve,
14-0 high-pressure heater water side outlet electrodynamic valve,
15-0 high-pressure heater water side entrance electrodynamic valve,
The hydrophobic electrodynamic valve of 16-0 high-pressure heater,
17-0 high-pressure heater water side bypass electrodynamic valve.
Detailed description of the invention
The present invention providesIt is a kind of that heat pressing type extra-supercritical unit zero is high adds and switched systemWith raising fired power generating unit Economical Operation of Light-LoadedNovelTechnological process, this technological process core is hot press and No. 0 high-pressure heater and the related valve of connection thereof and pipe fitting, and other equipment are original unit equipment.Its Main Function is to increase the heating of one-level backheat in former heat regenerative system of drawing gas, and not only increases the unit heat-economy when underload, and can effectively improve economizer exit cigarette temperature, it is ensured that the removal efficiency of denitrating system under running on the lower load;Additionally input of this set technological process can effectively improve pathogenic wind-warm, and alleviates under high pressure ablation operating mode the impact to unit heat economy and boiler safety.
In order to solve the problems referred to above of prior art, invent the high switched system added of a kind of heat pressing type extra-supercritical unit zero, this system mainly comprises boiler (1), steam turbine high-pressure cylinder (2), Steam Turbine Through IP Admission (3), No. 0, No. 1, No. 2, No. 3 high-pressure heaters (4, 5, 6, 7), oxygen-eliminating device (8), hot press (9) and feed pump (10) and connect the valves and fittings of relevant apparatus, main valve has: hot press high-pressure side intake valve (11), hot press low-pressure side intake valve (12), hot press air bleeding valve (13), No. 0 high-pressure heater water side outlet electrodynamic valve (14), No. 0 high-pressure heater water side entrance electrodynamic valve (15), No. 0 hydrophobic electrodynamic valve of high-pressure heater (16), No. 0 high-pressure heater water side bypass electrodynamic valve (17).
At height when system is run, can switch under low load condition: in the case of high load capacity, hot press high-pressure side intake valve (11), hot press low-pressure side intake valve (12), hot press air bleeding valve (13), No. 0 high-pressure heater water side outlet electrodynamic valve (14), No. 0 high-pressure heater water side entrance electrodynamic valve (15), No. 0 hydrophobic electrodynamic valve of high-pressure heater (16) is turned off, open No. 0 high-pressure heater water side bypass electrodynamic valve (17), No. 0 high adding system does not puts into operation, No. 1 high-pressure heater water outlet is directly entered unit heat vapo(u)rization system;Under low load condition, hot press high-pressure side intake valve, hot press low-pressure side intake valve, hot press air bleeding valve, No. 0 high-pressure heater water side outlet electrodynamic valve, No. 0 high-pressure heater water side entrance electrodynamic valve, No. 0 hydrophobic electrodynamic valve of high-pressure heater is all opened, close No. 0 high-pressure heater water side bypass electrodynamic valve, No. 0 high-pressure heater puts into operation, No. 1 high-pressure heater water outlet enters the heating evaporation system entering back into original system after No. 0 high-pressure heater continues heating, to improve the feed temperature of boiler under low load condition.
System run time hot press power steam take from boiler main steam, the steam being sucked can connect from original system 1 section draw gas (asAccompanying drawing 1) or 2 sections draw gas (asAccompanying drawing 2), mixed vapour after coupling enters No. 0 high-pressure heater heating boiler feed water, and it is hydrophobic flows automatically to No. 1 high-pressure heater, hydrophobic heat, measures further recovery.
In this system, No. 0 high-pressure heater is hydrophobic flows automatically to No. 1 high-pressure heater, if Reconstruction in field does not satisfies the requirements, No. 0 HP heater drainage also can be directly discharged to oxygen-eliminating device, but relatively the former economy decreases.
Referring now to prior art, the advantage of the application is:
1, by increasing No. zero high switched system that adds, improve unit feed temperature under low loading conditions, thus significantly improve the economy of unit variable parameter operation;
2, effectively reduce economizer exit cigarette temperature, advantageously ensure that the properly functioning of denitrating system;
3, height can be alleviated to a certain extent and add excision to unit heat economy and the impact of boiler safety.
Case study on implementation:
As a example by certain power plant 1000MW extra-supercritical unit, hot press power steam takes from main steam, aspirates mixed vapour after one section of steam and enters No. 0 high-pressure heater, is calculated under 50%, 75% loading condiction, after transformation with transformation before unit thermal parameter such asFollowing table instituteShow, under 75% loading condiction, input zero high adding, reduces 29kj/ (kW.h) before rear heat consumption relatively puts into, 32kj/ (kW.h) is reduced under 50% loading condiction, calculate with boiler efficiency 93%, mark coal low heat valve 29300kj/kg, under 75% loading condiction, unit generation coal consumption reduces 1.075g/kWh, and under 50% loading condiction, unit generation coal consumption reduces 1.186g/kWh.Calculate with 3,000,000,000 kWh with annual electricity generating capacity in this load section, about 3300 tons of coal of mark can be saved every year, there is significant energy-saving and emission-reduction benefit.
Thus, utilize hot press that first order regenerative steam can be made to heat feedwater in the heater of more high pressure, thus significantly improve the heat-economy of unit variable parameter operation;The coal dust wind pushing temperature under low load condition can also be ensured, maintain the flameholding in stove, reduce combustible loss;And it is possible to be effectively improved the flue-gas temperature of economizer exit under low load condition, thus ensure the denitration efficiency of flue gas;Further, it is possible to alleviate to a certain extent when height adds excision unit heat economy and the impact of boiler safety.
In the description of this specification, the description of reference term " embodiment ", " some embodiments ", " example ", " concrete example " or " some examples " etc. means that the specific features, structure, material or the feature that combine this embodiment or example description are contained at least one embodiment or the example of the present invention.In this manual, the schematic representation of above-mentioned term is necessarily directed to identical embodiment or example.And, the specific features of description, structure, material or feature can be to combine in one or more embodiments in office or example in an appropriate manner.Additionally, in the case of the most conflicting, the feature of the different embodiments described in this specification or example and different embodiment or example can be combined and combine by those skilled in the art.
Although above it has been shown and described that embodiments of the invention, it is understandable that, above-described embodiment is exemplary, it is impossible to be interpreted as limitation of the present invention, and above-described embodiment can be changed, revises, replace and modification by those of ordinary skill in the art within the scope of the invention.Protection scope of the present invention is defined by the claims.