A kind of power plant boiler fume afterheat energy conserving system
(1) technical field
The invention belongs to a kind of power plant boiler fume afterheat energy conserving system, can make mill coal pulverizer system reduce and mix the produced clean amount of energy saving maximization of leaking out, can also heat in advance for boiler water.
(2) technical background
The exhaust gas temperature of boiler of power plant design is at present at 120~150 ℃, and the boiler energy loss forming due to exhaust gas temperature is one maximum in all losses of boiler of power plant.The technological approaches that reduces exhaust gas temperature comprises and reduces the flue-gas temperature of (containing air preheater outlet) flue before air preheater outlet and reduce air preheater outlet with the large class of flue-gas temperature two of rear pass.The mature technology that belongs to the former comprises that high-pressure economizer extension, air preheater increase-volume, preheater rotor change direction of rotation, reduce a wind-warm syndrome etc.The mature technology that belongs to the latter comprises low-pressure coal saver, flue gas hot net water etc.In determining an energy-conservation technical reform scheme, when other condition is identical, should be preferably with reducing the air preheater outlet measure of flue-gas temperature in the past.
The technical equipment of any one Mist heat recovering, all can be when producing forward amount of energy saving, the energy consumption that brings certain negative sense, and the principal mode of this consumption is that air-flow pressure drop increase causes that station service changes.From Energy Angle analysis, what good energy-saving technical scheme should be pursued is the clean amount of energy saving that forward amount of energy saving and negative sense consume sum minimum.For power plant, it is the reduction to greatest extent of pursuing supply standard coal consumption rather than generating standard coal consumption.
(3) summary of the invention
The present invention, in order to make up the deficiencies in the prior art, provides a kind of power plant boiler fume afterheat energy conserving system that can make full use of boiler smoke heat, reduce heat waste.
The present invention is achieved through the following technical solutions:
A kind of power plant boiler fume afterheat energy conserving system, comprise air preheater, rotatable air-cooler, feedwater piping and water return pipeline, according to the trend of hot flue gas, the air outlet slit of air preheater is connected the rotatable air-cooler for heat exchange successively with heat primary air passage through air duct, air preheater is also provided with air intake, air preheater also connects exhaust gases passes, it is characterized in that: rotatable air-cooler comprises shell, framework, tube bank, enter, outlet header, rotatory sealing cover, swing pinion, rotation central axis, installation frame in shell, by framework, be provided with rotatable tube bank, restrain and in-built condensed water vertical with wind direction, tube bank one end is provided with import header, the other end is provided with outlet header, import header and outlet header are arranged on framework by rotation central axis respectively, on rotation central axis, be positioned at framework outside rotatory sealing cover and swing pinion are installed, thereby swing pinion is driven and is driven tube bank rotation by rotation status output mechanism, import header is overlapped and is connected feedwater piping by rotatory sealing, outlet header is overlapped and is connected water return pipeline by rotatory sealing, water return pipeline connects oxygen-eliminating device and control system, in housing, there is hot blast to move from the inlet to the outlet, rotatable air-cooler gas outlet is provided with temperature sensor one and baroceptor, the gas outlet of rotatable air-cooler connects coal pulverizer air inlet through cold-hot wind hybrid chamber, the air inlet of coal pulverizer is provided with temperature sensor two, control system comprises temperature sensor one, temperature sensor two and comparator, actuator, also comprises the four PLC controllers that connect therewith, and PLC controller also connects rotation status output mechanism.
Feedwater piping is all connected low-pressure heater with water return pipeline; The air duct that the air intake of air preheater connects is provided with boiler fan.
The rotation of formed working face is restrained in rotatable air-cooler utilization, changes mean wind speed between effective heat transfer area and pipe, realizes the adjusting that pulverized coal preparation system is mixed to cold blast rate, according to the difference of the tube bank anglec of rotation, with following four kinds of basic models, carries out work:
A) at full capacity during pattern, the anglec of rotation is 0 degree, and working face all launches, and device transmits maximum heat, and pulverized coal preparation system is mixed cold blast rate and reduced at most, and device air-pressure drop is also maximum;
B) during sub-load pattern, the anglec of rotation is between 0 ~ 90 degree, and working face partly launches, and device transmission needs heat, pulverized coal preparation system to mix cold blast rate to reduce on demand, and device air-pressure drop reduces;
C) during zero load pattern, the anglec of rotation is 90 degree, and working face is parallel with air flow, installs out of servicely, and the air-pressure drop of device is close to zero;
D) during blowback pattern, the anglec of rotation is 180 degree, and working face oppositely windward, is implemented, from purging, to blow the dust in tube bank off, the long-term exchange capability of heat of holdout device and drag reduction operation.
The invention has the beneficial effects as follows, can make full use of boiler smoke heat, reduce heat waste, help is reduced to boiler smoke temperature the design temperature of 120~150 ℃, by residual heat from boiler fume heating boiler water, water after low-pressure heater heating is further heated, while making the heating of boiler water input high-pressure heater, save energy, thereby be boiler water gasification saving energy.Flue gas after heating boiler water heats for the coal dust of mill coal pulverizer system, and by the temperature of control system and rotatable air-cooler regulation output hot blast, makes hot blast meet the temperature of coal pulverizer requirement.Rotatable air-cooler can be realized the heat exchange function of hot blast and water, can also regulate the anglec of rotation of tube bank, controls heat exchange efficiency, can also oppositely blow ash, prevents from restraining dust stratification.
(4) accompanying drawing explanation
Fig. 1 is the structural representation of power plant boiler fume afterheat energy conserving system.
In figure, 1-boiler fan; 2-air preheater; 3-exhaust gases passes; 4-air duct; 5-heat primary air passage; The rotatable air-cooler of 6-; 7-import header; 8-outlet header; 9-feedwater piping; 10-water return pipeline; Wind-warm syndrome before 11-mixes; Wind-warm syndrome after 12-mixes; 13-controller; 14-rotation status output mechanism; 15-control valve; 16 boosters; 17-low-pressure heater, 18-control system, 19-oxygen-eliminating device.
Fig. 2 is the schematic top plan view of rotatable air-cooler inside.Fig. 3 is the partial enlarged drawing of Fig. 2.Fig. 4 is the front view of Fig. 2, is also simultaneously to restrain state diagram during at full capacity with blowback.Fig. 5,6 restrains state diagram while being successively zero load and sub-load.
In figure, 7-import header; 8-outlet header; 20-rotatory sealing cover; 21-framework; 22-tube bank; 24-swing pinion; 25-rotation central axis; 26-rotary sleeve; 27-shell.
Fig. 7 is that rotatable air-cooler is controlled schematic diagram by control system.
In figure, 13-controller (adjuster); 14-rotation status output mechanism; 23 temperature sensors one; 28 temperature sensors two; 31-difference signal; 32-given difference signal; 29-comparator; 30-actuator.
(5) specific embodiment
Accompanying drawing is a kind of specific embodiment of the present invention.
A kind of power plant boiler fume afterheat energy conserving system, comprise air preheater 2, rotatable air-cooler 6, feedwater piping 9 and water return pipeline 10, according to the trend of hot flue gas, the air outlet slit of air preheater is connected the rotatable air-cooler for heat exchange successively with heat primary air passage 5 through air duct 4, air preheater is also provided with air intake, air preheater also connects exhaust gases passes 3, rotatable air-cooler comprises shell 27, framework 21, tube bank 22, import header 7, outlet header 8, rotatory sealing cover 20, swing pinion 24, rotation central axis 25 and rotary sleeve 26, installation frame in shell, by framework, be provided with rotatable tube bank, restrain and in-built condensed water vertical with wind direction, tube bank one end is provided with import header, the other end is provided with outlet header, import header and outlet header are arranged on framework by rotation central axis respectively, on rotation central axis, be positioned at framework outside rotatory sealing cover and swing pinion are installed, thereby swing pinion is driven and is driven tube bank rotation by rotation status output mechanism, import header is overlapped and is connected feedwater piping by rotatory sealing, outlet header is overlapped and is connected water return pipeline by rotatory sealing, water return pipeline connects oxygen-eliminating device and control system, in housing, there is hot blast to move from the inlet to the outlet, rotatable air-cooler gas outlet is provided with temperature sensor one and baroceptor, the gas outlet of rotatable air-cooler connects coal pulverizer air inlet through cold-hot wind hybrid chamber, the air inlet of coal pulverizer is provided with temperature sensor two, control system comprises temperature sensor 1, temperature sensor 2 28 and comparator 29, actuator 30, also comprises the four PLC controllers 13 that connect therewith, and PLC controller also connects rotation status output mechanism 14.
Feedwater piping is provided with booster 16, and water return pipeline is provided with control valve 15.
Feedwater piping is all connected low-pressure heater 17 with water return pipeline; The air duct that the air intake of air preheater connects is provided with boiler fan 1.
Inlet tube and outlet tube is coaxial concentric with rotatory sealing cover.
Rotatable air-cooler is as heat balance device, be installed on after air preheater outlet, in the heat primary air road before coal pulverizer import, by Gong Shui manage ﹑ water return pipeline, booster is connected with the main condensate pipeline of steam turbine back heating system.The working face of rotatable air-cooler can, along self axis Rotate 180 degree, be realized the heat transfer power that regulates rotatable air-cooler and two functions of carrying out online reverse gas cleaning.Realize in the process of first function the rotation between 0 degree~90 degree of the working face of rotatable air-cooler, the maximal heat transfer power stage of " 0 " degree position corresponding intrument, the zero thermal power output of " 90 " degree position corresponding intrument.The difference of the wind-warm syndrome before and after being mixed according to hot blast, cold wind by power governor is carried out closed-loop adjustment and switching.Realize in the process of second function, the working face Rotate 180 degree of rotatable air-cooler, former lee face becomes the high speed of a wind of windward side acceptance and blows ash.
Adopt rotatable air-cooler to regulate heat transfer power, the cooling water inflow of device can remain that high value is constant, thereby eliminated pipeline, produces the possibility of vaporization, water attack.
Tube bank 22 material be 20 steel (base tube, GB3087) and 08AL (fin), the material of import and export header 23 is 20 steel (GB3087), the material of framework 21 is Q235A.Rotatory sealing cover 20 adopts stainless steel to make.
Described power governor is PLC adjuster (being PLC controller), and its conditioning signal and regulated variable are the poor of the hot air temperature of coal pulverizer import and cold outlet temperature.By given difference signal 32, controlled the cold wind incorporation of coal pulverizer.The difference of the wind-warm syndrome before and after power governor (being PLC controller) mixes according to hot blast, cold wind is carried out closed-loop adjustment and switching.According to the inhomogeneous degree of coal pulverizer Mill output, change the size of the poor set-point of wind-warm syndrome, regulate and reduce the minimum that pulverized coal preparation system is mixed cold wind.
13-controller (adjuster); 14-rotation status output mechanism; 23 temperature sensors one; 28 temperature sensors two; 31-difference signal; 32-given difference signal; 29-comparator; 30-actuator.
Heat primary air in heat primary air passage 5 is after heat primary air machine cooler 6 is cooling, temperature is reduced to 230 ℃ from 320 ℃ and enters coal pulverizer, automatic control system is accepted the hot blast temperature signal 11 before coal pulverizer mixes, compare with mixed hot blast temperature signal 12, output difference value signal 31, PLC controller 13 is by for example 10 ℃ of given difference signal 32() compare by comparator 29 with difference signal 31, then export regulating command to actuator 30, then send to rotation status output mechanism 14, by swing pinion, drive tube bank to rotate, control the anglec of rotation of rotatable air-cooler, change heat transfer area and flow resistance.The adjusting of realization to heat transfer power.In adjustment process, the cooling water inflow that flows through heat primary air machine cooler 6 remains unchanged all the time or slightly adjusts, and avoids the interior appearance vaporization of cooling line feedwater piping 9 and water return pipeline 10 and water attack.
The rotation of formed working face is restrained in rotatable air-cooler utilization, change mean wind speed between effective heat transfer area and pipe, the adjusting of cold blast rate is mixed in realization to pulverized coal preparation system, according to the difference of the tube bank anglec of rotation, with following four kinds of basic models, carry out work: a) at full capacity during pattern, the anglec of rotation is 0 degree, and working face all launches, device transmits maximum heat 5500KW, and device air-pressure drop is at 950pa; B) during sub-load pattern, the anglec of rotation is 40 degree, and working face partly launches, and device transmission needs heat 2500KW, and device air-pressure drop is at 440pa; C) during zero load pattern, the anglec of rotation is 90 degree, and working face is parallel with air flow, and device transmit mode is closed, and heat output is close to 2500KW zero, and the air-pressure drop of device is being not more than 40pa; D) during blowback pattern, the anglec of rotation is 180 degree, and working face oppositely windward, is implemented from purging, and device transmits maximum heat 5800KW, and device air-pressure drop is at 820pa.
The present invention has changed the regulative mode of existing heat primary air cooler heat transfer power, further reduces heat primary air flow resistance in adjustment process, pulverized coal preparation system is reduced and mix the produced clean amount of energy saving maximization of leaking out.While changing (as moisture in coal increases) in ature of coal, the newly-increased resistance of heat primary air reduces thereupon, and clean amount of energy saving increases relatively.Can to device, implement online from deashing by the momentum of heat primary air own simultaneously, maintain the stable of clean amount of energy saving.