Boiler installation. Introduction
How is a CHP set up? CHP units. CHP equipment. CHP operating principles. CCGT-450.
Hello dear ladies and gentlemen!
When I studied at the Moscow Power Engineering Institute, I lacked practice. At the institute, you deal mainly with "pieces of paper", but I rather wanted to see "pieces of iron". It was often difficult to understand how this or that unit works, never having seen it before. The sketches offered to students do not always allow us to understand the full picture, and few could imagine the true design, for example, of a steam turbine, considering only the pictures in the book.
This page is designed to fill the existing gap and provide everyone who is interested, if not too detailed, but clear information about how the equipment of the Heat and Electric Central (CHP) is arranged "from the inside". The article considers a fairly new for Russia type of power unit CCGT-450, which uses in its work a combined cycle - combined cycle (most thermal power plants use only a steam cycle so far).
The advantage of this page is that the photographs presented on it were taken at the time of the construction of the power unit, which made it possible to shoot the device of some technological equipment disassembled. In my opinion, this page will be most useful for students of energy specialties - for understanding the essence of the issues being studied, as well as for teachers - for using individual photographs as methodological material.
The source of energy for the operation of this power unit is natural gas. During the combustion of gas, thermal energy is released, which is then used to operate all the equipment of the power unit.
In total, three power machines operate in the power unit scheme: two gas turbines and one steam one. Each of the three machines is designed for a rated electrical power output of 150 MW.
Gas turbines are similar in principle to jet aircraft engines.
Gas turbines require two components to operate: gas and air. Air from the street enters through the air intakes. The air intakes are covered with grilles to protect the gas turbine plant from birds and any debris. They also have an anti-icing system that prevents ice from freezing in winter period time.
The air enters the compressor inlet of the gas turbine plant (axial type). After that, in a compressed form, it enters the combustion chambers, where, in addition to air, natural gas is supplied. In total, each gas turbine plant has two combustion chambers. They are located on the sides. In the first photo below, the air duct has not yet been mounted, and the left combustion chamber is closed with a plastic film, in the second, a platform has already been mounted around the combustion chambers, and an electric generator has been installed:
Each combustion chamber has 8 gas burners:
In the combustion chambers, the process of combustion of the gas-air mixture and the release of thermal energy takes place. This is what the combustion chambers look like "from the inside" - just where the flame burns continuously. The walls of the chambers are lined with refractory lining:
At the bottom of the combustion chamber there is a small viewing window that allows you to observe the processes occurring in the combustion chamber. The video below demonstrates the process of combustion of the gas-air mixture in the combustion chamber of a gas turbine plant at the time of its start-up and when operating at 30% of the rated power:
The air compressor and gas turbine are on the same shaft, and part of the turbine's torque is used to drive the compressor.
The turbine produces more work than is required to drive the compressor, and the excess of this work is used to drive the "payload". As such a load, an electric generator with an electric power of 150 MW is used - it is in it that electricity is generated. In the photo below, the "gray barn" is just the electric generator. The generator is also located on the same shaft as the compressor and turbine. All together rotates at a frequency of 3000 rpm.
When passing through a gas turbine, the combustion products give it part of their thermal energy, but not all of the energy of the combustion products is used to rotate the gas turbine. A significant part of this energy cannot be used by the gas turbine, so the products of combustion at the outlet of the gas turbine (exhaust gases) still carry a lot of heat with them (the temperature of the gases at the outlet of the gas turbine is about 500° FROM). In aircraft engines, this heat is wastefully released into the environment, but at the power unit under consideration it is used further - in the steam power cycle.To do this, the exhaust gases from the outlet of the gas turbine are "blown" from below into the so-called. "heat recovery boilers" - one for each gas turbine. Two gas turbines - two waste heat boilers.
Each such boiler is a structure several floors high.
In these boilers, thermal energy exhaust gases A gas turbine is used to heat water and turn it into steam. Subsequently, this steam is used when working in a steam turbine, but more on that later.
For heating and evaporation, water passes inside tubes with a diameter of about 30 mm, arranged horizontally, and the exhaust gases from the gas turbine "wash" these tubes from the outside. This is how heat is transferred from gases to water (steam):
Having given up most of the thermal energy to steam and water, the exhaust gases are at the top of the waste heat boiler and are removed using a chimney through the roof of the workshop:
From the outside of the building, chimneys from two waste heat boilers converge into one vertical chimney:
The following photos allow you to estimate the dimensions of the chimneys. The first photo shows one of the "corners" by which the chimneys of waste heat boilers are connected to the vertical shaft of the chimney, the rest of the photos show the process of installing the chimney.
But back to the design of waste heat boilers. The tubes through which water passes inside the boilers are divided into many sections - tube bundles, which form several sections:
1. Economizer section (which at this power unit has a special name - Gas Condensate Heater - GPC);
2. Evaporation section;
3. Superheating section.
The economizer section is used to heat water from a temperature of about 40°Cto a temperature close to the boiling point. After that, the water enters the deaerator - a steel container, where the parameters of the water are maintained such that the gases dissolved in it begin to be intensively released from it. The gases are collected at the top of the tank and vented to the atmosphere. The removal of gases, especially oxygen, is necessary to prevent rapid corrosion of the process equipment with which our water comes into contact.
After passing the deaerator, the water acquires the name "feed water" and enters the feed pumps. This is what the feed pumps looked like when they were just brought to the station (there are 3 of them in total):
Feed pumps are electrically driven ( asynchronous motors powered by a voltage of 6kV and have a power of 1.3MW). Between the pump itself and the electric motor there is a hydraulic coupling - the unit,allows you to smoothly change the speed of the pump shaft over a wide range.
The principle of operation of the fluid coupling is similar to the principle of operation of the fluid coupling in automatic transmissions of cars.
Inside there are two wheels with blades, one "sits" on the motor shaft, the second - on the pump shaft. The space between the wheels can be filled with oil at different levels. The first wheel, rotated by the engine, creates a flow of oil that "hit" the blades of the second wheel, and entraining it in rotation. The more oil is filled between the wheels, the better the "cohesion" will be between the shafts, and the greater the mechanical power will be transmitted through the fluid coupling to the feed pump.
The oil level between the wheels is changed using the so-called. "scoop pipe", pumping oil from the space between the wheels. Regulation of the position of the scoop pipe is carried out using a special actuator.
The feed pump itself is centrifugal, multi-stage. Note that this pump develops the full steam pressure of the steam turbine and even exceeds it (by the value of the hydraulic resistance of the remaining part of the waste heat boiler, hydraulic resistance of pipelines and fittings).
The design of the impellers of the new feed pump it was not possible to see (because it had already been assembled), but parts of an old feed pump of a similar design were found on the territory of the station. The pump consists of alternating rotating centrifugal wheels and fixed guide discs.
Fixed guide disc:
Impellers:
From the outlet of the feed pumps, feed water is supplied to the so-called. "separator drums" - horizontal steel tanks designed to separate water and steam:
Each waste heat boiler is equipped with two separator drums (4 in total at the power unit). Together with the tubes of the evaporator sections inside the waste heat boilers, they form the circulation circuits of the steam-water mixture. It works as follows.
Water with a temperature close to the boiling point enters the tubes of the evaporator sections, flowing through which it is heated to the boiling point and then partially turns into steam. At the outlet of the evaporation section, we have a steam-water mixture, which enters the separator drums. Special devices are mounted inside the separator drums
which help to separate the steam from the water. The steam is then fed to the superheating section, where its temperature increases even more, and the water separated in the separator drum (separated) is mixed with feed water and again enters the evaporation section of the waste heat boiler.
After the superheating section, steam from one waste heat boiler is mixed with the same steam from the second waste heat boiler and enters the turbine. Its temperature is so high that the pipelines through which it passes, if thermal insulation is removed from them, glow in the dark with a dark red glow. And now this steam is served on steam turbine in order to give up part of its thermal energy in it and do useful work.
The steam turbine has 2 cylinders - a cylinder high pressure and cylinder low pressure. Low pressure cylinder - double flow. In it, the steam is divided into 2 streams operating in parallel. The cylinders contain the turbine rotors. Each rotor, in turn, consists of stages - disks with blades. "Hitting" the blades, the steam causes the rotors to rotate. The photo below reflects general design steam turbine: closer to us - a high pressure rotor, farther from us - a two-flow low pressure rotor
This is what the low pressure rotor looked like when it was just unpacked from the factory packaging. Notice it only has 4 steps (not 8):
And here is the high pressure rotor on closer inspection. It has 20 steps. Pay also attention to the massive steel casing of the turbine, consisting of two halves - the lower and upper (in the photo only the lower one), and the studs with which these halves are connected to each other. In order to make the case faster at start-up, but at the same time, it warms up more evenly, a steam heating system of "flanges and studs" is used - do you see a special channel around the studs? It is through it that a special steam flow passes to warm up the turbine casing during its start-up.
In order for the steam to "hit" the rotor blades and make them rotate, this steam must first be directed and accelerated in the right direction. For this, the so-called. nozzle arrays - fixed sections with fixed blades, placed between the rotating disks of the rotors. The nozzle arrays DO NOT rotate - they are NOT movable, and serve only to direct and accelerate the steam in the desired direction. In the photo below, steam passes "behind these blades at us" and "unwinds" around the axis of the turbine counterclockwise. Further, "hitting" the rotating blades of the rotor discs, which are located immediately behind the nozzle grate, the steam transfers its "rotation" to the turbine rotor.
In the photo below you can see the parts of the nozzle arrays prepared for installation.
And in these photos - lower part Turbine housing with nozzle array halves already installed in it:
After that, the rotor is "inserted" into the housing, the upper halves of the nozzle arrays are mounted, then the upper part of the housing, then various pipelines, thermal insulation and casing:
After passing through the turbine, the steam enters the condensers. This turbine has two condensers - according to the number of flows in the low pressure cylinder. Look at the photo below. It clearly shows the lower part of the steam turbine housing. Pay attention to the rectangular parts of the low pressure cylinder body, closed on top with wooden shields. These are steam turbine exhausts and condenser inlets.
When the steam turbine housing is fully assembled, a space is formed at the outlets of the low-pressure cylinder, the pressure in which during the operation of the steam turbine is about 20 times lower than atmospheric pressure, therefore the low-pressure cylinder housing is designed not for pressure resistance from the inside, but for pressure resistance from the outside - i.e. e. atmospheric air pressure. The condensers themselves are under the low pressure cylinder. The photo below is rectangular containers with two hatches on each.
The condenser is arranged similarly to the waste heat boiler. Inside it is a lot of tubes with a diameter of about 30mm. If we open one of the two hatches of each condenser and look inside, we will see "tube boards":
Cooling water flows through these tubes, which is called industrial water. Steam from the exhaust of a steam turbine is in the space between the tubes outside them (behind the tube plate in the photo above), and, giving off residual heat to process water through the walls of the tubes, condenses on their surface. The steam condensate flows down, accumulates in the condensate collectors (at the bottom of the condensers), and then enters the condensate pumps. Each condensate pump (and there are 5 in total) is driven by a three-phase asynchronous electric motor, designed for a voltage of 6 kV.
From the outlet of the condensate pumps, water (condensate) again enters the inlet of the economizer sections of the waste heat boilers and, thereby, the steam-power cycle is closed. The whole system is almost hermetic and the water, which is the working fluid, repeatedly turns into steam in waste heat boilers, does work in the form of steam in the turbine to turn back into water in the turbine condensers, etc.
This water (in the form of water or steam) is constantly in contact with the internal parts of the process equipment, and in order not to cause their rapid corrosion and wear, it is chemically prepared in a special way.
But back to the steam turbine condensers.
Industrial water, heated in the tubes of the steam turbine condensers, is removed from the workshop through underground industrial water supply pipelines and supplied to the cooling towers in order to transfer the heat taken from the steam from the turbine to the surrounding atmosphere. The photographs below show the design of the cooling tower built for our power unit. The principle of its operation is based on the spraying of warm technical water inside the cooling tower with the help of shower devices (from the word "shower"). Water droplets fall down and give off their heat to the air inside the cooling tower. The heated air rises, and in its place from the bottom of the cooling tower comes cold air from the street.
This is what the cooling tower looks like at its base. It is through the "slit" at the bottom of the cooling tower that cold air enters to cool the process water.
At the bottom of the cooling tower there is a catchment basin, where droplets of process water fall and collect, released from the choking devices and giving up their heat to the air. Above the pool there is a system of distribution pipes, through which warm technical water is supplied to showering devices.
The space above and below the showering devices is filled with a special stuffing of plastic blinds. The lower louvers are designed to more evenly distribute the "rain" over the area of the cooling tower, and the upper louvers are designed to trap small droplets of water and prevent excessive entrainment of technical water along with air through the top of the cooling tower. However, at the time the photographs were taken, the plastic shutters had not yet been installed.
Bo" The highest part of the cooling tower is not filled with anything and is intended only for creating draft (heated air rises). If we stand above the distribution pipelines, we will see that there is nothing above and the rest of the cooling tower is empty
The following video captures the experience of being inside the cooling tower
At the time when the photos of this page were taken, the cooling tower built for the new power unit was not yet operational. However, there were other cooling towers in operation on the territory of this CHP plant, which made it possible to capture a similar cooling tower in operation. Steel louvres at the bottom of the cooling tower are designed to regulate the flow of cold air and prevent overcooling of process water in winter
The process water cooled and collected in the cooling tower basin is again fed to the inlet of the steam turbine condenser tubes in order to take a new portion of heat from the steam, etc. In addition, process water is used to cool other process equipment, such as electric generators.
The following video shows how process water is cooled in a cooling tower.
Since industrial water is in direct contact with the surrounding air, dust, sand, grass and other dirt get into it. Therefore, at the inlet of this water to the workshop, on the inlet pipeline of technical water, a self-cleaning filter is installed. This filter consists of several sections mounted on a rotating wheel. Through one of the sections, from time to time, a reverse flow of water is organized for washing it. The section wheel then turns and the next section is flushed, and so on.
This is what this self-cleaning filter looks like from the inside of the process water pipeline:
And so outside (the drive motor has not yet been mounted):
Here we should make a digression and say that the installation of all process equipment in the turbine shop is carried out using two overhead cranes. Each crane has three separate winches designed to handle loads of different weights.
Now I would like to tell a little about the electrical part of this power unit.
Electricity is generated by three electric generators driven by two gas turbines and one steam turbine. Part of the equipment for the installation of the power unit was brought by road, and part by rail. A railroad was laid right into the turbine shop, along which large-sized equipment was transported during the construction of the power unit.
The photo below shows the delivery of the stator of one of the generators. Let me remind you that each electric generator has a rated electric power of 150 MW. Note that the railway platform on which the generator stator was brought has 16 axles (32 wheels).
The railway has a slight rounding at the entrance to the workshop, and given that the wheels of each wheel pair are rigidly fixed on their axles, when driving on a rounded section railway one of the wheels of each wheel pair is forced to slip (since the rails have different length). The video below shows how this happened when the platform was moving with the stator of the power generator. Pay attention to how the sand on the sleepers bounces when the wheels slip along the rails.
Due to the large mass, the installation of the stators of electric generators was carried out using both overhead cranes:
The photo below shows an internal view of the stator of one of the generators:
And this is how the installation of the rotors of electric generators was carried out:
The output voltage of the generators is about 20 kV. The output current is thousands of amperes. This electricity is taken from the turbine shop and fed to step-up transformers located outside the building. To transfer electricity from power generators to step-up transformers, the following electrical wires are used (current flows through a central aluminum pipe):
To measure the current in these "wires", the following current transformers are used (in the third photo above, the same current transformer stands vertically):
The photo below shows one of the step-up transformers. Output voltage - 220 kV. From their outlets, electricity is fed into the power grid.
In addition to electricity, the CHP also generates thermal energy used for heating and hot water supply of nearby areas. For this, steam extractions are made in the steam turbine, i.e., part of the steam is removed from the turbine without reaching the condenser. This one is enough hot steam, enters the network heaters. The network heater is a heat exchanger. It is very similar in design to a steam turbine condenser. The difference is that it is not technical water that flows in the pipes, but network water. There are two network heaters at the power unit. Let's look again at the photo with the turbine capacitors. Rectangular containers are capacitors, and "round" ones - this one is exactly network heaters. I remind you that all this is located under the steam turbine.
The network water heated in the pipes of network heaters is supplied through underground pipelines of network water to the heating network. Heating the building of the districts located around the CHPP, and having given them its heat, the network water returns to the station again to be heated again in the network heaters, etc.
The operation of the entire power unit is controlled by the automated process control system "Ovation" of the American corporation "Emerson"
And here is how the cable mezzanine, located under the APCS room, looks like. Through these cables, the process control system receives signals from a variety of sensors, as well as signals to actuators.
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Thermal power engineering in modern conditions cannot survive without water treatment. Lack of water purification and softening can lead to equipment failure, poor quality steam or water, and as a result, paralysis of the entire system. Constant descaling cannot insure you against such troubles as increased fuel consumption, the formation and development of corrosion. Only water treatment at CHP can solve the whole complex of problems in one fell swoop.
In order to better understand the problems of using one or another at thermal power plants, let's start with a review of the basic concepts. What is a combined heat and power plant, and how increased water hardness can interfere there normal operation systems?
So, CHP or combined heat and power plant is one of the types of thermal power plant. Its task is not only to generate electricity. It is also a source of thermal energy for the heating system. These stations supply hot water and steam to provide heat to homes and businesses.
Now a few words about how a thermal power plant works. It works like a condensing power plant. The fundamental difference in water treatment at a CHP is that it is possible to take some of the heat generated from a CHP for other needs. Methods of taking heat energy depends on the type of steam turbine that is installed at the enterprise. Also at the CHP you can regulate the amount of steam that you need to select.
Everything that is separated is then concentrated in a network heater or heaters. They are already transferring energy to the water, which goes further along the system to transfer its energy to peak hot water boilers and district heating stations. If such steam extraction is not performed at the CHPP, then such CHPP has the right to qualify as a CPP.
Any water treatment at a CHP works according to one of two load schedules. One of them is thermal, the other is electric. If the load is thermal, then the electrical one is completely subordinate to it. The thermal load has parity over the electrical one.
If the load is electrical, then it does not depend on the thermal load, perhaps there is no thermal load at all in the system.
There is also the option of combining water treatment at the CHPP for electrical and thermal loads. This helps the residual heat to be used for heating. As a result, the efficiency of a CHPP is much higher than that of a IES. 80 versus 30 percent. And yet - when building a thermal power plant, you need to remember that it will not work to transfer heat over long distances. Therefore, the CHP plant must be located within the city it feeds.
The main drawback is the insoluble precipitate that forms as a result of heating such water. Removing it is not easy. At the CHP, you will have to stop the entire system, sometimes disassemble it, in order to clean the scale in all turns and narrow holes with high quality.
As we already know, the main disadvantage of scale is its poor thermal conductivity. Because of this feature, the main costs and problems arise. Even a slight deposit of scale on the surfaces of heating surfaces or heating elements causes a sharp increase in fuel consumption.
Eliminating scale will not work all the time, it can be done at least once a month. At the same time, fuel costs will constantly grow, and the operation of the CHP leaves much to be desired, all heating and heating equipment is slowly but surely covered with scale. To clean it later, you have to stop the entire system. To suffer losses from downtime, but to clean the scale.
The equipment itself will let you know that it's time for cleaning. Overheating protection systems will suddenly start to work. If after that the scale is not removed, then it completely blocks the operation of heat exchangers and boilers, explosions and the formation of fistulas are possible. In just a few minutes, you can lose an expensive industrial equipment. And it's impossible to restore it. Just buy new.
And then, any descaling is always damaged surfaces. You can use water treatment at a thermal power plant, but it will not remove scale for you, then you still have to clean it off using mechanical equipment. Having such crooked surfaces, we run the risk of a sharp development of not only scale formation, but also corrosion. For the equipment of a combined heat and power plant, this is a big minus. Therefore, we thought about creating water treatment plants at CHP.
Water treatment at a mini CHP
Generally speaking, such a composition will depend primarily on the chemical analysis of water. It will show the amount of water that needs to be cleaned every day. It will show the impurities that need to be eliminated first. It is impossible to do without such an analysis when compiling water treatment at a mini-CHP. Even the degree of water hardness, he will show. You never know, all of a sudden, the water is not as hard as you think, and the problem is in silicon or iron deposits, and not at all in hardness salts.
Mostly for CHP equipment big problem make up impurities that are in the make-up water. These are the same salts of calcium and magnesium, as well as iron compounds. And this means that it will be at least difficult to do without an iron remover and an AquaShield electromagnetic water softener.
CHP is known to provide warm water and heating houses in the city. Therefore, water treatment at a mini-CHP will always include not only standard ones. Here you can’t do without auxiliary water filters. Approximately, the entire water treatment scheme can be represented in the form of such stages, and the filters contained in them.
For CHPs, water from primary sources is used, which is very polluted, so the first stage of water treatment at a mini CHP will be clarification. Here, in most cases, mechanical filters are used, as well as sedimentation tanks. The latter, I think, are understandable to everyone, they defend water there so that solid impurities settle.
Mechanical filters include several gratings made of of stainless steel. They trap all solid impurities in the water. First, these are large impurities, then medium ones, and at the end very small ones, the size of a grain of sand. Mechanical filters can be used with coagulants and flocculants to purify water from harmful bacteriological impurities.
Restore mechanical filters by normal backwashing with plain water.
Next stage water treatment at a mini thermal power plant- elimination of harmful bacteria and viruses or disinfection. To do this, they can use both cheap, but harmful bleach, and expensive, but harmless when completely evaporated. ozone.
Another option for water disinfection is the use of an ultraviolet filter. Here the basis is an ultraviolet lamp, which irradiates all the water passing through a special cuvette. Passing through such a filter, the water is irradiated, and all bacteria and viruses die in it.
After disinfection comes the stage. A variety of water filters can be used here. These can be ion-exchange units, the Aquashield electromagnetic water softener or its magnetic variation. We will talk about the advantages and disadvantages of each installation a little later.
In addition to standard filters, reagent sedimentation can also be used. But the addition of various impurities can then result in the formation of insoluble deposits that are very difficult to remove.
After the softening stage, it is time to demineralise the water. For this, anion filters are used, it is possible to use a calciner, an electrodiadizer, and, as a standard, reverse osmosis or nanofiltration.
After fine purification of water, it is imperative to remove residual dissolved gases from the water. To do this, deaerate the water. Thermal, vacuum, atmospheric deaerators. That is, we have done everything that is needed for make-up water. Now there are already general steps to prepare the system itself.
Then the boiler purge stage comes into effect, for this they use washing filters for water and the last stage of water treatment at a mini-CHP is steam washing. For this, a whole set chemical reagents for decontamination.
In Europe, the use of high-quality water treatment in CHP plants helps to achieve a loss efficiency of only a quarter of a percent per day. Just a combination traditional methods water softening and cleaning with the latest technologies helps to achieve such high results of the water treatment system at the mini CHP. And at the same time, the system itself can uninterruptedly last up to 30-50 years, without cardinal replacements of stages.
And now let's return to the water treatment system for CHP and to the water treatment plant for CHP. Here they use the whole range of filters, the main thing is to choose the right device. Most often, the system requires the use of not one, but several filters at once, connected in series, so that the water goes through both the softening stage and the demineralization stage.
The most commonly used is the ion exchange plant. In industry, such a filter looks like a tall tank in the form of a cylinder. It is necessarily equipped with a smaller tank, this is a filter regeneration tank. Since the CHP works with water around the clock, the ion exchange plant will be multi-stage and will include not one, but sometimes three or four filters. There is one control unit or controller for this entire system. Each filter is equipped with its own regeneration tank.
The controller carefully monitors how much water has passed through the unit. How much this or that filter cleaned, clearly fixes the cleaning time, cleaning speed, after certain period cleaning or a certain volume, it gives a signal for the installation. Hard water is redistributed to other filters, and the contaminated cartridge is sent for recovery. To do this, it is removed from the installation and transferred to a tank for regeneration.
The process itself water treatment systems for CHP proceeds according to the following scheme. The heart of such an ion exchange cartridge is a resin enriched with mild sodium. When hard water comes into contact with it, metamorphoses occur. Strong hardness salts replace weak sodium. Gradually, the entire cartridge becomes clogged with hardness salts. This is the time for recovery.
When the cartridge is transferred to the recovery tank, highly purified salt tablets are already dissolved there. The saline solution that results is very saturated. The percentage of salt content is not less than 8-10 percent. But only like this big amount salts can be removed from the cartridge strong hardness salts. As a result of washing, highly salted waste is formed, and a cartridge refilled with sodium. He is sent to work, but there is a problem with waste. To dispose of them, they must be re-cleaned, that is, the degree of salinity must be reduced and permission for disposal must be obtained.
This is a big minus of the installation, and the cost of salt is considerable, which also gives expensive maintenance to the installation. But the water purification rate of this softener is the highest.
The next popular version of the water treatment system for thermal power plants is the AquaSHIELD electromagnetic water softener. Here, the main work is performed by an electric processor, a board and powerful permanent magnets. All this together creates a powerful electromagnetic field. These waves enter the water through a wire wound on both sides of the device. Moreover, you need to remember that you need to wind the wires in different directions from each other. Each wire must be wrapped around the pipe at least seven times. When operating this device, it is imperative to ensure that water does not get on the wiring.
The ends of the wires themselves must be closed with insulating rings or ordinary electrical tape. So, water passes through the pipe, it is irradiated electromagnetic waves. It seems to many that the influence of this is mythical. However, hardness salts under its influence begin to transform, lose their former shape and turn into thin and sharp needles.
Having received new form, sticking to equipment surfaces becomes inconvenient. The thin narrow body of the needle does not adhere to surfaces. But on the other hand, it perfectly tears off the old scale from the walls of the equipment. And he does it subtly and efficiently, without using any auxiliary means. Such work is the main trump card of the AquaShield electromagnetic water softener. He will do his job, that is, he will soften the water and remove the old scale very efficiently. And for this you do not have to buy anti-scale products. All will provide powerful permanent magnets made of rare earth metals and electric current.
At this appliance a large number of advantage over other installations. He does not need to be looked after, he does everything himself. It will completely remove from your everyday life such a thing as descaling. It is able to work with any surfaces, the main thing is to mount it on a clean piece of pipe.
Then electromagnetic device can work without replacement for a quarter of a century. Such a long use is guaranteed just by rare earth metals, which over time practically do not lose their magnetic properties. Here, even the water does not get used to the magnetic effect. True, such a device does not work with standing water. Also, if the water flows in more than two directions at the same time, the magnetic field does not work either.
And finally, a few words about reverse osmosis as a water treatment system for thermal power plants. It is impossible to manage in the production of make-up water without this installation. Only it guarantees almost one hundred percent water purification. There are replaceable membranes that allow you to get water with the desired characteristics. But at the same time, the device cannot be used independently. Only bundled with other softeners, which makes installation more expensive. But one hundred percent compensates for all the disadvantages of high cost.
We have considered in detail all water treatment systems for CHP. Familiarized with all possible softeners that can be used in this system. Now you can easily navigate the world of softening.
March 23rd, 2013
Once, when we were driving into the glorious city of Cheboksary, from the east, my wife noticed two huge towers standing along the highway. "And what is it?" she asked. Since I absolutely did not want to show my ignorance to my wife, I dug a little in my memory and gave out a victorious one: "These are cooling towers, don't you know?". She was a little embarrassed: "What are they for?" "Well, there's something to cool, it seems." "And what?". Then I was embarrassed, because I did not know at all how to get out further.
Maybe this question has remained forever in the memory without an answer, but miracles do happen. A few months after this incident, I see a post in my friend feed z_alexey about the recruitment of bloggers who want to visit the Cheboksary CHPP-2, the same one that we saw from the road. Having to drastically change all your plans, it would be unforgivable to miss such a chance!
So what is CHP?
This is the heart of the CHP plant, and here the main action takes place. The gas entering the boiler burns out, releasing a crazy amount of energy. This is where Pure Water comes in. After heating, it turns into steam, more precisely into superheated steam, having an outlet temperature of 560 degrees and a pressure of 140 atmospheres. We will also call it "Pure steam" because it is formed from prepared water.
In addition to steam, we also have exhaust at the exit. On the maximum power, all five boilers consume almost 60 cubic meters of natural gas per second! To remove the products of combustion, a non-childish "smoke" pipe is needed. And there is one too.
The pipe can be seen from almost any area of the city, given the height of 250 meters. I suspect that this is the tallest building in Cheboksary.
Nearby is a slightly smaller pipe. Reserve again.
If the CHP plant is coal-fired, additional exhaust treatment is required. But in our case, this is not required, since natural gas is used as fuel.
In the second section of the boiler and turbine shop there are installations that generate electricity.
Four of them are installed in the engine room of the Cheboksary CHPP-2, with a total capacity of 460 MW (megawatts). It is here that superheated steam from the boiler room is supplied. He, under huge pressure, is sent to the turbine blades, forcing the thirty-ton rotor to rotate at a speed of 3000 rpm.
The installation consists of two parts: the turbine itself, and a generator that generates electricity.
And here is what the turbine rotor looks like.
Sensors and gauges are everywhere.
Both turbines and boilers, in case emergency can be stopped instantly. For this, there are special valves that can shut off the supply of steam or fuel in a fraction of a second.
Interestingly, is there such a thing as an industrial landscape, or an industrial portrait? It has its own beauty.
There is a terrible noise in the room, and in order to hear a neighbor, you have to strain your hearing a lot. Besides, it's very hot. I want to take off my helmet and strip down to my T-shirt, but I can't do that. For safety reasons, short-sleeved clothing is prohibited at the CHP plant, there are too many hot pipes.
Most of the time, the workshop is empty, people appear here once every two hours, during a round. And the operation of the equipment is controlled from the Main Control Board (Group Control Panels for Boilers and Turbines).
This is what it looks like workplace on duty.
There are hundreds of buttons around.
And dozens of sensors.
Some are mechanical and some are electronic.
This is our excursion, and people are working.
In total, after the boiler and turbine shop, at the output we have electricity and steam that has partially cooled down and lost part of its pressure. With electricity, it seems to be easier. At the output from different generators, the voltage can be from 10 to 18 kV (kilovolt). With the help of block transformers, it rises to 110 kV, and then electricity can be transmitted to long distances with the help of power lines (power lines).
It is unprofitable to release the remaining "Clean steam" to the side. Since it is formed from "Pure Water", the production of which is a rather complicated and costly process, it is more expedient to cool it and return it to the boiler. So by vicious circle. But with its help, and with the help of heat exchangers, you can heat water or produce secondary steam, which can be easily sold to third-party consumers.
In general, it is in this way that we receive heat and electricity in our homes, having the usual comfort and coziness.
Oh yes. Why are cooling towers needed anyway?
It turns out everything is very simple. In order to cool the remaining "Pure steam", before a new supply to the boiler, all the same heat exchangers are used. It is cooled with the help of technical water, at CHPP-2 it is taken directly from the Volga. It does not require any special training and can also be reused. After passing through the heat exchanger, process water is heated and goes to the cooling towers. There it flows down in a thin film or falls down in the form of drops and is cooled by the oncoming air flow created by the fans. And in ejection cooling towers, water is sprayed using special nozzles. In any case, the main cooling occurs due to the evaporation of a small part of the water. The cooled water leaves the cooling towers through a special channel, after which, with the help of pumping station sent for reuse.
In a word, cooling towers are needed to cool the water that cools the steam that works in the boiler-turbine system.
All work of the CHP is controlled from the Main Control Panel.
There is an attendant here at all times.
All events are logged.
Don't feed me bread, let me take pictures of the buttons and sensors...
On this, almost everything. In conclusion, there are a few photos of the station.
This is an old, no longer working pipe. Most likely it will be taken down soon.
There is a lot of propaganda at the enterprise.
They are proud of their employees here.
And their achievements.
It doesn't seem right...
It remains to add that, as in a joke - "I don't know who these bloggers are, but their guide is the director of the branch in Mari El and Chuvashia of OAO TGC-5, the IES of the holding - Dobrov S.V."
Together with the station director S.D. Stolyarov.
Without exaggeration - true professionals in their field.
And of course, many thanks to Irina Romanova, representing the press service of the company, for the perfectly organized tour.
Interactive application "How CHP works"
Pictured on the left is the Mosenergo power plant, which generates electricity and heat for Moscow and the region. The most environmentally friendly fuel - natural gas - is used as fuel. At the CHP plant, gas is supplied through a gas pipeline to a steam boiler. The gas burns in the boiler and heats the water.
To make the gas burn better, draft mechanisms are installed in the boilers. Air is supplied to the boiler, which serves as an oxidizing agent in the process of gas combustion. To reduce the noise level, the mechanisms are equipped with silencers. The flue gases formed during the combustion of fuel are discharged into chimney and dissipate in the atmosphere.
The hot gas rushes through the flue and heats the water passing through the special tubes of the boiler. When heated, the water turns into superheated steam, which enters the steam turbine. Steam enters the turbine and begins to rotate the turbine blades, which are connected to the generator rotor. Steam energy is converted into mechanical energy. In the generator, mechanical energy is converted into electrical energy, the rotor continues to rotate, creating an alternating electric current in the stator windings.
through a step-up transformer and a step-down transformer substation electricity is supplied to consumers through power lines. The steam exhausted in the turbine is sent to the condenser, where it turns into water and returns to the boiler. At the thermal power plant, water moves in a circle. Cooling towers are designed to cool water. The CHP uses fan and tower cooling towers. Water in cooling towers is cooled by atmospheric air. As a result, steam is released, which we see above the cooling tower in the form of clouds. The water in the cooling towers rises under pressure and falls like a waterfall down into the fore-chamber, from where it flows back to the CHP. To reduce droplet entrainment, the cooling towers are equipped with water traps.
Water supply is provided from the Moscow River. In the chemical water treatment building, water is purified from mechanical impurities and enters the filter groups. On some of them, it is prepared to the level of purified water to feed the heating system, on others - to the level of demineralized water and goes to feed the power units.
The cycle used for hot water supply and district heating is also closed. Part of the steam from the steam turbine is sent to the water heaters. The hot water is then sent to heat points where heat exchange takes place with the water coming from the houses.
High-class specialists of Mosenergo support the production process around the clock, providing the huge metropolis with electricity and heat.
How does a combined cycle power unit work
One of the most important issues in the energy sector has been and remains water treatment at thermal power plants. For energy companies, water is the main source of their work, and therefore very high requirements are imposed on its content. Since Russia is a country with a cold climate, constant severe frosts, the operation of a thermal power plant is something on which people's lives depend. The quality of the water supplied to the heat and power plant greatly affects its operation. Hard water results in a very serious problem for steam and gas boilers, as well as steam turbines of thermal power plants, which provide the city with heat and hot water. In order to clearly understand how and what exactly hard water negatively affects, it would not hurt to first understand what a CHP is? And with what it "eat"? So, a CHPP - a heat and power plant - is a kind of thermal power plant that not only provides heat to the city, but also supplies hot water to our homes and enterprises. Such a power plant is designed as a condensing power plant, but differs from it in that it can take part of the thermal steam after it has given up its energy.
Steam turbines are different. Depending on the type of turbine, steam with different indicators is selected. Turbines in the power plant allow you to adjust the amount of steam taken. The steam that has been extracted is condensed in the network heater or heaters. All energy from it is transferred to network water. Water, in turn, goes to peak water heating boiler houses and heat points. If the steam extraction paths are blocked at the CHPP, it becomes a conventional IES. Thus, the heat and power plant can operate according to two different load curves:
- thermal graph - direct proportional dependence of the electrical load on the thermal;
- electrical graph - there is either no heat load at all, or the electrical load does not depend on it. The advantage of CHP is that it combines both heat and electricity. Unlike IES, the remaining heat does not disappear, but is used for heating. As a result, the efficiency of the power plant increases. For water treatment at CHPPs, it is 80 percent versus 30 percent for IES. True, this does not speak of the efficiency of the heat and power plant. Here in the price there are other indicators - the specific generation of electricity and the efficiency of the cycle. The peculiarities of the location of the CHP should include the fact that it should be built within the city. The fact is that the transfer of heat over distances is impractical and impossible. Therefore, water treatment at CHPPs is always built near consumers of electricity and heat. What is the water treatment equipment for CHP? These are turbines and boilers. Boilers produce steam for turbines, turbines produce electricity from steam energy. The turbine generator includes a steam turbine and synchronous generator. Steam in turbines is obtained by using fuel oil and gas. These substances heat the water in the boiler. The pressurized steam turns the turbine and the output is electricity. Waste steam is supplied to homes in the form of hot water for household needs. Therefore, the exhaust steam must have certain properties. Hard water with a lot of impurities will not allow you to get high-quality steam, which, moreover, can then be supplied to people for use in everyday life. If the steam is not sent to supply hot water, then it is immediately cooled in the thermal power plant in cooling towers. If you have ever seen huge pipes at thermal stations and how smoke pours from them, then these are cooling towers, and smoke is not smoke at all, but the steam that rises from them when condensation and cooling occurs. How does water treatment work on fuel cells? The most affected by hard water is the turbine and, of course, boilers that convert water into steam. The main task of any thermal power plant is to get clean water in the boiler. Why is hard water so bad? What are its consequences and why do they cost us so much? Hard water differs from ordinary water by its high content of calcium and magnesium salts. It is these salts that, under the influence of temperature, settle on heating element and walls household appliances. The same applies to steam boilers. Scale forms at the heating point and the boiling point along the edges of the boiler itself. Descaling in the heat exchanger in this case is difficult, because. scale builds up on huge equipment, inside pipes, all kinds of sensors, automation systems. Flushing the boiler from scale on such equipment is a whole multi-stage system that can even be carried out when disassembling the equipment. But this is the case high density scale and its large deposits. The usual remedy for scale in such conditions, of course, will not help. If we talk about the consequences of hard water for everyday life, then this is the impact on human health and the rise in the cost of using household appliances. In addition, hard water is very bad in contact with detergents. You will use 60 percent more powder, soap. Costs will grow by leaps and bounds. Water softening was therefore invented to neutralize hard water, you put one water softener in your apartment and forget that there is a descaling agent, a descaling agent.
Scale is also characterized by poor thermal conductivity. This shortcoming of hers main reason breakdowns dear household appliances. A thermal element covered with scale simply burns out, trying to give off heat to the water. Plus due to poor solubility detergents, washing machine you need to additionally turn on the rinse. These are the costs of water and electricity. In any case, water softening is the surest and most cost-effective way to prevent scale formation. Now imagine what is water treatment at a CHP in industrial scale? There, the descaler is used by the gallon. Flushing the boiler from scale is carried out periodically. It happens regularly and repair. To make descaling more painless, water treatment is needed. It will help prevent the formation of scale, protect both pipes and equipment. With it, hard water will not exert its destructive effect on such an alarming scale. If we talk about industry and energy, then most of all hard water brings trouble to thermal power plants and boiler houses. That is, in those areas where there is direct water treatment and heating of water and the movement of this warm water through water pipes. Water softening is as necessary here as air. But since water treatment at a thermal power plant is work with huge volumes of water, water treatment must be carefully calculated and thought out, taking into account all sorts of nuances. From analysis chemical composition water and the location of a particular water softener. In CHP, water treatment is not only a water softener, it is also equipment maintenance after. After all, descaling will still have to be done in this production process, with a certain frequency. More than one descaler is used here. It can be formic acid, and citric, and sulfuric. In various concentrations, always in the form of a solution. And they use one or another solution of acids, depending on which of which constituent parts made boiler, pipes, controller and sensors. So, which energy facilities need water treatment? These are boiler stations, boilers, this is also part of the CHPP, water heating installations, pipelines. Pipelines remain the weakest points, including CHPs. Scale accumulating here can also lead to depletion of pipes and their rupture. When the scale is not removed in time, it simply does not allow water to pass through the pipes normally and overheats them. Along with scale, the second problem of equipment in CHP is corrosion. It also cannot be left to chance. What can lead to a thick layer of scale in the pipes that supply water to the CHP? This is a difficult question, but we will answer it now knowing what water treatment at a CHP is. Since scale is an excellent heat insulator, the heat consumption increases sharply, while the heat transfer, on the contrary, decreases. The efficiency of boiler equipment drops significantly, and as a result, all this can lead to rupture of pipes and explosion of the boiler.
Water treatment at a thermal power plant is something that cannot be saved on. If in everyday life, you still think about whether to buy a water softener or choose a descaling agent, then for thermal equipment such bargaining is unacceptable. At thermal power plants, every penny is counted, so descaling in the absence of a softening system will cost much more. And the safety of devices, their durability and reliable operation also play a role. Descaled equipment, pipes, boilers work 20-40 percent more efficiently than equipment that has not been cleaned or works without a softening system. main feature water treatment at a thermal power plant is that it requires deeply demineralized water. To do this, you need to use precise automated equipment. In such production, reverse osmosis and nanofiltration, as well as electrodeionization, are most often used. What stages does water treatment in the energy sector include, including at a heat and power plant? The first stage includes mechanical cleaning from all kinds of impurities. At this stage, all suspended impurities are removed from the water, up to sand and microscopic rust particles, etc. This is the so-called coarse cleaning. After it, the water comes out clean for the human eye. Only dissolved hardness salts, ferrous compounds, bacteria and viruses, and liquid gases remain in it.
When developing a water treatment system, it is necessary to take into account such a nuance as the source of water supply. This tap water from systems centralized water supply Or is it water from a primary source? The difference in water treatment is that the water from the water supply systems has already passed the primary treatment. Only hardness salts should be removed from it, and deferrized if necessary. Water from primary sources is absolutely untreated water. That is, we are dealing with a whole bouquet. Here it is necessary to carry out chemical analysis water, in order to understand what impurities we are dealing with and what filters to install to soften the water and in what sequence. After coarse cleaning The next step in the system is called ion-exchange demineralization. An ion exchange filter is installed here. Works on the basis of ion-exchange processes. Main element- ion exchange resin, which includes sodium. It forms weak bonds with resin. As soon as hard water at a thermal power plant enters such a softener, the hardness salts instantly knock sodium out of the structure and firmly take its place. Restoring such a filter is very simple. The resin cartridge is moved to the recovery tank, where the saturated brine is located. Sodium takes its place again, and hardness salts are washed into the drain. The next step is to obtain water with desired characteristics. Here, a water treatment plant is used at a thermal power plant. Its main advantage is getting 100 percent clean water, with the given indicators of alkalinity, acidity, mineralization level. If the company needs industrial water, then the reverse osmosis plant was created just for such cases.
The main component of this installation is a semi-permeable membrane. The selectivity of the membrane varies, depending on its cross section, you can get water with different characteristics. This membrane divides the tank into two parts. One part contains a liquid with a high content of impurities, the other part contains a liquid with a low content of impurities. Water is launched into a highly concentrated solution, it slowly seeps through the membrane. Pressure is applied to the installation, under the influence of it, the water stops. Then the pressure is sharply increased, and the water begins to flow back. The difference between these pressures is called osmotic pressure. The output is perfectly pure water, and all deposits remain in a less concentrated solution and are discharged into the drain.
Nanofiltration is essentially the same reverse osmosis, only low-pressure. Therefore, the principle of operation is the same, only the water pressure is less. The next stage is the elimination of gases dissolved in it from the water. Since CHP plants need pure steam without impurities, it is very important to remove oxygen, hydrogen and oxygen dissolved in it from water. carbon dioxide. The elimination of impurities of liquid gases in water is called decarbonation and deaeration. After this stage, the water is ready for supply to the boilers. Steam is obtained at exactly the concentration and temperature that is needed.
As can be seen from all of the above, water treatment in a CHP is one of the most important components of the production process. Without clean water, there will be no good quality steam, which means there will be no electricity in the right amount. Therefore, water treatment in thermal power plants should be dealt with tightly, trust this service exclusively to professionals. A properly designed water treatment system is a guarantee of long-term equipment service and quality energy supply services.