CN101372905A

CN101372905A - Energy-saving improvement (comprehensive utilization of heat energy) of thermal power station conventional heat engineering system

Info

Publication number: CN101372905A
Application number: CNA200610135889XA
Authority: CN
Inventors: 戴克发
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-10-14
Filing date: 2006-10-14
Publication date: 2009-02-25

Abstract

Since the 1950s, our country has started to produce whole sets of firepower plant equipment, and the layout of a boiler plus a turbo generator group plus a condenser has always been adopted in the thermal system of the firepower plant. In the layout system, natural water is used for condensing the tail gas of a steamer into water, and the boiloff latent heat of the tail gas is regarded as 'waste' and discharged out of the system, which is the basic reason for the extremely low thermal efficiency (approximately 32 to 40 percent) of the thermal system in the system, and is a global persistent ailment that has not been solved so far. The invention proposes the theory and implementation method for the comprehensive utilization of thermal energy. The core technology of the invention is to develop independent and innovative tail gas superheater of the steam turbine to replace the air preheater of the original boiler; the tail gas of the steam turbine after being overheated is used for heating and burning air on the one hand, and for producing a large amount of hot water (approximately 100 degrees centigrade) on the other hand, and even for producing low-pressure micro-steam gas; and the hot water and the low-pressure micro-steam gas can be supplied as a second product of the power plant.

Description

The energy-conservationization transformation (comprehensive utilization of heat energy) of thermal power station's tradition heat power engineering system

China is since last century, early fifties was produced the homemade 6000KW of first cover thermal power station equipment, through semicentennial painstaking efforts, the hundreds of seats of large and medium-sized thermal power station have been built up in the whole nation now, and total installation of generating capacity breaks through 300,000,000 KW, and annual consume fuel is converted into the mark coal and reaches 7～800,000,000 tons.Considerable making a leapleap forward also arranged aspect power station technology, basically near or reach advanced world standards.

But thermal power station's thermal efficiency is not high is a typical worldwide persistent ailment, does not obtain adequate solution so far, and China is no exception.With boiler+Turbo-generator Set+condensing plant is the conventional thermal power station heat power engineering system of representative, and its utilization efficiency of heat energy has only 32～40%.Even adopted extremely high-tech supercritical parameter unit also can only reach about 40% difficultly, and the extreme of the construction of this unit and maintenance cost is risen to rise and also is difficult to the energy large size employing by China institute.

With thermal power station's utilization efficiency of heat energy 40% is that example is analyzed, and the effusion approach that can find primary energy aggregate supply 60% heat energy is removed some in addition outside the loss such as the partial combustion of stars and run, drip, leak, and two main loss channels are arranged:

(1) the useless flue gas of boiler chimney discharge has been taken away 6.5～7.5% of fuel thermal energy, and invalid row is to atmosphere.

(2) steamer tail vapour is via condensation device, and the water that is cooled (or cooling air) has been carried off away the nearly about 50% of fuel thermal energy, and invalid row is to nature.

Both stacks amount to about 57% fuel thermal energy and are slipped away by these two channels.These two channels are to cause the low prime responsibility person of thermal power station's thermal efficiency.The only effective means of therefore seeking to improve thermal power station's thermal efficiency is to catch boiler exhaust gas thermal loss and steamer tail vapour thermal loss, uses by oneself.

But exhaust gas temperature has dropped between 150～160 ℃, and steamer tail vapour also has only 0.05 absolute pressure and about 33 ℃.The waste gas of this low temperature and low pressure and tail vapour can't directly be used by thermal power station again, can only listen its invalid loss.Applicant draws a conclusion thus: outlet is

Be exactly that the unserviceable waste gas of traditional heat power engineering system and some technical innovation of tail vapour process are pressed by thermal power station, be converted into the utilizable valuable energy of other departments.This is the broad road of a comprehensive utilization.

Present patent application theoretical propose one and joins together with useless flue gas and tail vapour according to above, at first steamer tail vapour is changed into the superheated low pressure vapor of high temperature, is produced the design proposal of high temperature (100 ℃ of ≈) circulating hot water again by the low pressure steam of high temperature.Thus conventional thermal power station is only produced the constant established practice of single electric energy, become one and both produced electric energy, produce the enterprise of high-temperature-hot-water again.Approach by comprehensive utilization can rise to 70～80% by 32～40% with the thermal efficiency of thermal power station, even as for higher.

Fig. 1 is the heat power engineering system figure of conventional thermal power station.The new heat power engineering system schematic representation that Fig. 2 proposes for this patent.Be not difficult to find out that both differ very not big.That is to say, the design that present patent application proposes has kept the effective ingredient that mature experience is arranged as far as possible, just make the change of some principles at boiler tail, increased some technology compositions very not high, the mature experience equipment supported arranged, its starting point is to adapt to China's national situation, only increase few equipment investment, just conventional thermal power station can be transformed into energy-saving and environmental protection, high-efficiency power station, help large size and promote.

Fig. 1 is typical thermal technology's system schematic of conventional thermal power station.Combustion product gases is finally arranged to atmosphere through chimney with about 150～160 ℃ temperature through the heat transfer process of evaporating system EV, superheater SH, economizer EC and air preheater AH.The steam that evaporating system EV produced that is arranged in around the CC of firing chamber reaches 520～750 ℃ superheat temperature through heating of superheater SH, guides steam turbine then into, and the high pressure heat energy of steam is converted to the mechanical energy of rotation, and rotating generator produces electric energy.In this transfer process, remove extract some in, low pressure steam supplies with outside the needs of water system, the shank of steam is all brought into play the effect that it produces mechanical energy as far as possible in steam turbine, up to reaching quite low pressure area (about 0.05 absolute pressure), at this moment, its temperature also has been reduced to corresponding saturation temperature (about 33～35 ℃).This low-pressure low-temperature steam no longer can be utilized by conventional thermal power station, can only pass through condenser SC (or cooling tower CT, not shown) with nature water (or cool air) latent heat of vaporization of tail vapour is taken out, to obtain condensed water (its heat content is about 30 kilocalorie/kilograms), return the water supply system of boiler.Be condensed in the process of water at tail vapour, natural water (or cool air) is taken away the latent heat of vaporization of about 600 kilocalorie/kilograms that tail vapour is contained, and row is to nature.The latent heat of vaporization of these 600 kilocalorie/kilograms accounts for about 41～45% (having considered about 20% intermediate extraction in this conversion) of original superheated vapor heat content (818～906 kilocalorie/kilogram).This thermal loss and heat loss due to exhaust gas stack up and account for more than 50% of thermal power station's consumption prime energy (fuel) total amount of heat.The main cause of Here it is traditional hot power station thermal effect not high (having only about 32～40%).

Present patent application proposes brand-new thermal power station's heat power engineering system at the above two thermal loss, sees shown in Figure 2.Fig. 2 and Fig. 1 compare, as seen the structure of boiler from firing chamber (CC) to economizer (EC1) till, basically remain unchanged, and after economizer EC1, original place at air preheater AH1, change into arrange tail vapour superheater SH ', its effect be with steamer tail stripping temperature by about 35 ℃, rise to about 130～150 ℃ or higher.Tail vapour is through guiding a heat exchanger HE into after overheated, and the high temperature Heating Cyclic water after utilizing tail vapour overheated has produced second product---the high-temperature water of thermal power station thus.This high-temperature water quantity is very big, is carrying about about 50% the heat of power station energy total flow, is very considerable energy resources, and its utilization may be derived from a series of new industrial chains that great DEVELOPMENT PROSPECT is arranged.

Two new equipments shown in Figure 2 (tail vapour superheater SH ' and heat exchanger HE) are simple heat transmission equipments, and the former heats tail vapour, and the latter then bears the desuperheat of overheated tail vapour, to produce high temperature circulation water and condensed water.

The design of these two new equipments has but run into a same thorny difficult problem, and that is exactly the disappearance of tail vapour physical property data.Applicant is all over looking into the related physical data that the home and abroad data can not find low pressure steam like this (for example the heat content of low-pressure superheated steam, specific volume or the like).Applicant requires the enterprise have a mind to implement the art of this patent, must have the spirit and the ability of the frontier of bravely rushing forefathers and not set foot in, and dare to have the attitude of " look for the truth in practice and know " in force in arms, creates the data of oneself.The disappearance of these data has also been proved the steam that home and abroad scientific and technological circle do not have contacted this low-pressure low-temperature at all in one aspect, and to let alone be to be used.

Fig. 3 shows the structural representation of tail vapour superheater SH '.The tube bank that heat exchanger surface is arranged horizontally, tail vapour is discharged by below introducing, top.The orthogonal thereto reverse flow of steam flow and flue gas flow direction is in the hope of the highest superheat temperature of acquisition steam and the minimum discharge temperature of flue gas.Because of the volume of low pressure tail vapour very huge, so the steel pipe of larger caliber is adopted in tube bank.Both can adopt snakelike tubular (as shown in Figure 6) of the common employing of conventional superheater and economizer, also can adopt the form (as shown in Figure 5) of straight tube+tube sheet.

If tail vapour superheater SH ' has substituted the position of the former air preheater preheater first order (AH1) fully, in the time of still can not satisfying the hot water user to the requiring of hot water temperature, tail vapour superheater SH ' still can " invade " the part status of economizer (EC1).When causing air preheating temperature can not satisfy some fuel if tail vapour superheater SH ' has replaced former air preheater (AH1) to the requiring of air temperature, (similar of air pre-heating arrangement is not given unnecessary details in Fig. 5, shown in Figure 6 then can to heat inlet air by backup line with the overheated tail vapour of part.)

Fig. 4 shows the heat exchanger (HE) of overheated tail vapour and circulating water, its structure and above-mentioned tail vapour superheater (SH ') similar, if when adopting above measure still can not satisfy the hot water user to the requiring of hot water temperature, it is also conceivable that the tail steam pressure (to 0.5 absolute pressure) of suitable lifting steam turbine, its way is deletion steam turbine afterbody blade 1～2 row.Overheated tail vapour is introduced by the top, and condensed water is discharged by the below.Circulating water is introduced by the below, and discharge the top.Also be orthogonal thereto reverse flow, in the hope of obtaining the highest hot water temperature and forming condensed water as early as possible.

Fig. 5 shows the structural representation of straight tube plate-tube type tube bank.Straight tube can be to rise to connect or weld with being connected of tube sheet.

Fig. 6 shows the structural representation of snakelike tube bank type, is similar to the form of common superheater and economizer.Because of the steel pipe (φ 40～50 or bigger) of this patent requirement larger caliber, pipe is quite intensive apart from also requiring, and the elbow of coiler just can not adopt common bent tube technique.The mode of the weld ell of the attached detail drawing of Fig. 6 is adopted in the present patent application suggestion, and wherein elbow partly can adopt Forging Technology production.

In a word, the overheated tail vapour of elder generation that present patent application proposes, utilize its Heating Cyclic water then, produce a large amount of high-temperature-hot-waters, this is the effective way of " seizure " power station effusion heat energy, neither involves unsurmountable technical barrier and implement this technology, do not involve excessive equipment investment yet, and its result very improves rate of energy really significantly, and economic benefit is very remarkable, please industry pay attention to.

Special suggestion

1. after adopting the art of this patent, the thermal equilibrium of former boiler may be subjected to certain interference, its limit is that requirement increases some firing rates (estimate can not increase and surpass 1～2%) only, its effect then can firmly be caught the latent heat of vaporization (being approximately 600 kilocalorie/kilograms) of tail vapour, just the heat energy of about 50% original invalid effusions of fuel thermal energy is firmly caught, its interests are fairly obvious.

2. the employing of this patent promotes big spoke the thermal efficiency of thermal power station, require no longer to pursue simply that ultrahigh pressure even supercritical parameter equipment are the sort of does not stint with huge fund and technical risk to exchange the way that does not suit China's national situation that the thermal efficiency promotes 2-3% for, please China's industry pay close attention to.

3. present patent application will be produced hot water after implementing in a large number, and it rationally utilizes problem is a problem that extremely merits attention.Applicant proposes following suggestion:

1. as the power station intensive town dweller district is arranged in the neighbourhood, in northern each province, power station hot water can be used as the usefulness of life heating, to replace numerous poor efficiency high pollution equipment such as cooking stove.

2. there are many manufacturing enterprises to need the usefulness of a large amount of hot water, very welcome this inexpensive and free of contamination thermal source, even as near the power station, attracting these enterprises to form a new industrial production district for production.

3. near the power station, can carry out the chamber planting cause on a large scale.Can open up large-scale chamber planting district at northern area, produce nuisanceless, low energy consumption, low water consumption quality vegetables, fruit and flowers with high-tech technology (temperature adjusting, the regulation and control of atmosphere composition, illumination regulation and control, high-quality wrong season, the cultivation of wrong zone variety, soilless culture or the like) in the batch production mode, supply in the neighbourhood, so that it is inside and outside to find a good sale in the sea, being one has the very industrial chain of bright prospects, merits attention.

4. the narration of patent specification is illustrated emphatically and has been built thermal power station and adopt the theory and the technology of this patent to carry out the approach that energy-conservationization house of correction is followed.Applicant needs special the proposition, designs and builds if plan to build the theory and the technology implementation of thermal power station's employing present patent application, and the energy-saving effect that can obtain more to optimize is because can consider this moment

Claims

1. present patent application proposes to add Hot gas turbine tail vapour to obtain overheated tail vapour with boiler exhaust gas, again with overheated tail vapour Heating Cyclic water, reach thermal power station except that first product (electric energy), increase one second product (high-temperature-hot-water) again newly, realize the comprehensive utilization of heat energy, to promote core theory and the basic fundamental that thermal power station's utilization efficiency of heat energy is a this patent significantly, never be indicated in the introduction of home and abroad theory journal and medium, be a brand-new theory and technology.

2. present patent application proposes the brand-new design of tail vapour superheater SH ', replaces air preheater first order AH1 (even as for again and then the some of alternative economizer first order EC1) is a brand-new design intention of present patent application, never being indicated in the introduction of theory journal and medium, is a brand-new design creativity.

3. when if present patent application has proposed to have substituted air preheater first order AH1 and cause hot air temperature not reach some fuel to the requiring of hot air temperature owing to tail vapour superheater SH ', can use the design of the overheated tail vapour heating of part import cool air, be a brand-new design creativity, never be indicated in the introduction of theory journal and medium.

4. present patent application proposes the brand-new design of the heat exchanger HE of overheated tail vapour and circulating water, to obtain condensed water and high temperature circulation water, is a brand-new design creativity, never is indicated in the introduction of theory journal and medium.