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Steam Power Plant: A Guide to Components, Working Principle and Applications
- 3. ACKNOWLEDGEMENT 1. SYNOPSIS 2. INTRODUCTION 3. THERMAL POWER PLANT 4. COMPONENTS AND DESCRIPTION 5. WORKING PRINCIPLE 6. ADVANTAGES AND DISADVANTAGES 7. APPLICATIONS 8. LIST OF MATERIALS 9. COST ESTIMATION 10.CONCLUSION BIBLIOGRAPHY PHOTOGRAPHY --------------------------------------------------------------------------------------- Chapter-1 ---------------------------------------------------------------------------------------
- 5. CHAPTER-1 SYNOPSIS Steam Power Plant is convert Mechanical rotary energy into Electrical energy. A mechanical interface, consisting of a boiler, heater and a suitable coupling transmits the energy to an electrical generator. The output of this generator is connected to the Battery or system grid. The battery is connected to the inverter. The inverter is used to convert DC voltages to AC voltages. The load is drawn current from the inverter. • Generator • Mains shaft with Leafs • Amount of Steam (or) Pressure The power ratings can be divided into three convenient grouping, small to 1kW, medium to 50 kW and large 200 kW to megawatt frame size.
- 7. CHAPTER-2 INTRODUCTION MAN AND ENERGY: Man has needed and used energy at an increasing rate for its sustenance and well being ever since he came on the earth a few million years ago. Primitive man required energy primarily in the form of food. He derived this by eating plants or animals, which he hunted. Subsequently he discovered fire and his energy needs increased as he started to make use of wood and other bio mass to supply the energy needs for cooking as well as agriculture. He added a mew dimension to the use of energy by domesticating and training animals to work for him. With further demand for energy, man began to use the wind for sailing ships and for driving windmills, and the force of failing water to turn water wheels. Till this time, it would not be wrong to say that the sun was supplying all the energy needs of man either directly or indirectly and that man was using only renewable sources of energy. The industrial revolution, which began with the discovery of the steam engine (AD 1700), brought about great many changes. For the first time, man began to use a new source of energy, viz. coal, in large quantities.
- 8. A little later, the internal combustion engine was invented (AD1870) and the other fossil fuels, oil and natural combustion engine extensively. The fossil fuel era of using non-renewable sources had begun and energy was now available in a concentrated form. The invention of heat engines and then use of fossil fuels made energy portable and introduced the much needed flexibility in mans movement. For the first time, man could get the power of a machine where he required it and was not restricted to a specific site like a fast-running stream for running a water wheel or a windy hill for operating a windmill. This flexibility was enhanced with the discovery of electricity the development of central power generating stations using either fossil fuels or waterpower. A new source of energy-nuclear energy-came on the scene after the Second World War The first large nuclear power station was commissioned about 40 years ago, and already, nuclear energy is providing a small but significant amount of the energy requirements of many countries. Thus today, every country draws its energy needs from a variety of sources. We can broadly categorize these sources as commercial and noncommercial. The commercial sources include the fossil fuels (coal, oil and natural gas), hydroelectric power and nuclear power, while the non-commercial sources include wood, animal wastes, geothermal energy and agricultural wastes.
- 9. In an industrialized country like USA, most of the energy requirements are meant from commercial sources, while in an industrially less developed country like India, the use of commercial and noncommercial sources is about equal. In the past few years, it has become obvious that fossil fuel resources are fast depleting and that the fossil fuel era is gradually coming to an end. This is particularly true for oil and natural gas. It will be use full there fore to first examine the rates of consumption of the different sources of energy and to give some indication of the reserves available this study will be done for the world as a whole and then for India in particular with the help of these figures it will be possible to form estimates of the time periods for which the existing source will be available. The need for alternative energy options will thus be established and these options will then be briefly described. Before passing on to these topics, it is worth noting that while man’s large-scale use of commercial energy has led to a better quality of life it has also created many problems. Perhaps the most serious of these is the harmful effect on the environment. The combustion of the fossil fuel has caused serious air pollution problems in many areas because of the localized release of large amounts of harmful gases into the atmosphere. It has also resulted in the phenomenon of global warning, which is now a matter of great concern. Similarly the releases of large amounts of waste heat from power plants have caused thermal pollution in lakes and rivers leading to the destruction of many forms of plants and animals life.
- 10. In the case of nuclear power plants there is also concern over the possibility of radio activity being released into the atmosphere in the event of an accident and over the long term problems of disposal of radioactive wastes from these plants. The gravity of most of these environmental problems had not really been foreseen. Now however, as man embarks on the search for alternative sources of energy, it is clear that the would do well to keep the environmental in mind. So her we take geothermal energy as a project and discussed below.
- 12. CHAPTER-3 THERMAL POWER PLANT The steam generator unit has to produce steam at highest purity, and at high pressure and temperature required for the turbine. This is made up of Economizer, the steam drum with all internal and external fittings and chemical dosing arrangement, generating tubes (with necessary headers for uniform distribution of water flow) forming the Furnace chamber and superheater coils. Necessary safety valves are located at suitable points to avoid excessive boiler pressure. Air and gas path equipment are: forced draught fan (FD fan), air preheater (APH), boiler furnace, induced draft fan (ID fan), mechanical and electrical dust precipitators and the Stack or Chimney. For units of about 200 megawatt (MW) capacity, FD fan, APH, dust collectors and ID fan are duplicated with necessary isolating dampers. On some units of about 60 MW. The boiler furnace has mounted on it the coal nozzles and igniter guns, soot blowers, and water lancing. Necessary ports on furnace walls with safety covers for manual observation inside the furnace are provided. Necessary air vents and drains are provided on steam drum, superheater coils and headers etc. for initial start up and for maintaining the boiler water concentration. Mounted equipment
- 13. Economizer, air preheater, etc. External fans are provided to give sufficient air for combustion. The Forced Draft(FD) fan takes air from atmosphere and injects it through the airpreheater to the air nozzles on the boiler furnace to give hot air for better combustion. The ID fan sucks out or draws out the combustible gases from the furnace to assist FD fan and to maintain always slightly negative pressure in the furnace to avoid backfiring through any opening. Just at the outlet of furnace and before the furnace gases are handled by ID fan, fine dust carried by the outlet gases are removed to avoid atmospheric pollution (environmental limitations prescribed by law) as well as to minimize erosion of ID fan rotors etc. The drum internals provided are such that the wet steam entering the drum from the generating tubes is removed of moisture, and then the dry steam enters the superheater coils. Furnace explosions due to accumulation of combustible gases after a trip out are avoided by flushing out these gases from combustion chamber before starting igniters. The general location of equipment in the boiler cycle is shown in the schematic sketch. The boilers come under the statutory inspection of Chief Boiler Inspectorate in every state in India.
- 14. The coal crushed to about ¾ inch (6 mm) in size from the coal yard is conveyed and stored in the boiler hoppers above the boilers. The coal then passes through pipes to the coal feeders for regulating and measuring coal quantity, then to coal pulverizers for pulverizing coal, and then to a pulverized coal bin. The pulverizers may be of rotary drum type or ball or roller grinder type. In some power stations what is known as residual oil is used as main fuel. This oil congeals (becomes solid like wax) below about 50 °C due to its high content of wax, about 50%. This oil therefore is always kept above this temperature even in storage tanks to make it pumpable. For spraying into the furnace the oil temp at burner tips is maintained at about 100 °C. For all instruments on this oil line lagging or heat insulation is provided for their proper working. This oil is transported from refinery direct by means of oil wagons provided with steam heating coils. This oil is generally loaded at the refinery at about 80 °C. The pipe line carrying this oil is lagged (insulated) at all points. Some boilers in some power stations use natural gas also as main fuel. Fuel preparing system
- 15. Gas taken out from gas wells is sent to group gathering station nearby at about 600 psi (4.1 MPa) by reducing the well pressure at wellhead by means of a Beans orifice (named after the inventor) installed in the outlet of the Christmas tree at the well head. At the group gathering station the pressure is further reduced by pressure reducing stations and the separated liquid, known as condensate (highly volatile like petrol) in petroleum industry (not to be confused with steam condensate), is stored in tanks for disposal separately. The gas at outlet of group gathering station at about 40 kgf/cm² (4 MPa) is sent to power station about 20 miles (30 km) away by pipeline, wrapped and protected for electrolytic corrosion. At the power station site the gas pressure is further reduced to about 20 kgf/cm² (2 MPa) and supplied to the electricity utility company. The gas up to the point of supply to utility is handled by a Government of India organization known as the Oil and Natural Gas Corporation. The gas at boiler burners is at about one half kgf/cm² (50 kPa), and separate gas burners are provided for this on the boilers. From the pulverized coal bin coal is conveyed by hot air injectors through coal pipes to boiler coal burners of one tier or level at a horizontal angle into the furnace to give a swirling action for powdered coal for proper mixing of coal powder and also the incoming hot air from FD fans, to give the best combustion. Fuel firing system and igniter system
- 16. If the system does not have pulverized coal bin then coal powder is conveyed directly to coal burners from pulverizes. Then generally one tier is fed by one pulverizer. To provide sufficient combustion temperature in the furnace before spraying powdered coal to catch fire or ignite, the furnace temperature is brought up by spraying and burning light oil by means of igniter oil guns. Oil is used in a fine spray, as oil can catch fire even in ambient temperature. Alternatively gas is also used for ignition instead of oil, if available in plenty. However in this case the igniter gun design differs. To ignite the ignition oil or gas, an Electric High Tension spark in the path of oil or gas is used momentarily and then the spark gun is withdrawn. External to boiler unit Fly ash collection equipment and disposal Dust separators are provided immediately at the outlet of the furnace and before the ID fan. They are of mechanical type or electrical type, sometimes mechanical followed by electrical type to reduce the load on the electrical type and also may be to comply with the provisions of law. The dust normally is collected in hoppers below them. They are emptied periodically by water jet ejectors or by air suction depending on how they are further disposed off.
- 17. In case of further use of this fine ash, it is generally handled dry by air and taken to a silo located at a higher level for loading the fine ash in trucks from bottom of silo. In case of these being dumped in the yard, then wet method by water jet injectors is employed. Boiler make-up water treatment plant and storage Since steam is taken out continuously and returned to the boiler, losses due to blow-downs and leakages have to be made up for maintaining designed boiler water quantity by means of the level gauges provided on the boiler drum. For this, continuous make up water is added to the boiler water system. Since this make up requires pure water this quality water is obtained by a Demineralised (DM) water treatment plant. However some storage is essential as DM plant may be down for maintenance. For this purpose a storage tank is installed from which continuously DM water is drawn for boiler make up.The impurities in water input to this plant generally consist of calcium and magnesium salts imparting hardness to the water. These salts have to be removed from the water. If hardness is present in make up water to the boiler, the salts not only form deposits on the tube water surfaces but also lead to overheating in those localities resulting in tube failures. Therefore these have to be completely removed for use as boiler make up. This is done using DM water treatment plant which gives the purest form of water.
- 18. This generally consists of cation, anion and mixed bed exchangers. The final water from this process consists essentially of hydrogen ions and hydroxide ions which is the chemical composition of pure water. The DM water being very pure becomes highly corrosive, once it absorbs oxygen from the atmosphere because of its very high affinity for oxygen absorption. The capacity of the DM plant is dictated by the type and quantity of salts in the raw water input. The storage tank for DM water is made from materials not affected by corrosive water, such as PVC. The piping and valves are generally of stainless steel. Sometimes on top of the water in the tank a steam blanketing arrangement or stainless steel doughnut float is provided to avoid contact with atmosphere. DM water make up is generally added to the boiler/TG cycle at the steam space of condenser, i.e. vacuum side. This arrangement not only sprays the water but also DM water gets deaerated, with the dissolved gases being removed by the ejector of the condenser itself. ---------------------------------------------------------------------------------------
- 20. CHAPTER-4 COMPONENTS AND DESCRIPTION The physical setup of this project are given below and it is been explained as follows 1. Boiler Unit 2. Battery 3. Inverter 4. D.C Generator 5. Lighting Load BOILER UNIT: Boiler is used to produce the steam from the water by heating water by using any methods. In our project, the flow lamp is used to heat the water and this water is converted into the steam.
- 21. BOILER TYPES:- Conventional Boilers:- In a conventional boiler gas jets play onto a cast iron heat exchanger through which water passes to be heated. If used to supply taps, hot water cannot be provided on demand but must be stored, usually in a copper cylinder. This type of boiler has relatively simple controls and tends to be more reliable as less can go wrong. Energy consumption can be high but the cost of this is moderated by the low maintenance costs. They are versatile in that they can be used in almost any type of property and can be pumped or gravity fed. Combination Boilers A combination boiler heats water for the central heating in the same way as a conventional boiler but can also provide the taps with instant hot water. The main difference is that the hot water for the taps is fed directly from the mains rather than from a hot water storage cylinder. This can also be useful in a small property where space for a cylinder is at a premium. The internal workings are increasingly technical and can be perceived as unreliable but are becoming more accepted.
- 22. Other than the lack of an airing cupboard one problem can be that in the event of a breakdown the user can be without both heating and hot water whereas on a conventional system an electric immersion element can usually be inserted into the cylinder to provide hot water for the taps. With a combination boiler, hot water and central heating requirements are provided from the one unit. As well as providing central heating water into the radiators, it provides all of the domestic water for baths, sinks, and showers. The big advantage with a combination boiler, or a "combi" as it is usually called, is that it not only delivers continuous hot water, but more importantly delivers it at mains pressure too. So, with a combi system you can have a really effective shower without needing an expensive "Power Shower" booster pump. Combis are also considered to be amongst the easiest systems to install, because they eliminate the need for both an expansion tank in the loft and a hot water cylinder in an airing cupboard. The combi does have limitations. Most standard combis take 40 seconds to heat water. Combis provide maximum pressure through only one tap at a time. If you have two taps running, the powerful flow rate is diminished in one (or both) of the taps. So, if you want high temperature and a high output flow rate from your combi, choose a high capacity or a storage combi.
- 23. Combination Storage Boilers By adding a storage tank to a combi, the problems of flow rate reduction are progressively overcome, depending upon the size of the tank. Now you can use a couple of taps simultaneously, without an unacceptable drop in performance. The advantage of this system over a conventional boiler and storage tank is that the hot water never runs out. Even after running a bath, a combi storage boiler doesn't need time to recover before you can use it again. So there's no need to plan your hot water requirements, hot water is always there. However, the flow rate from an average combi storage boiler does not match the high flow rate from a modern system with an unvented storage tank. System Boilers Like conventional boilers, a system boiler can provide central heating and hot water from a cylinder if required. The key difference with a system boiler is that all the major components are built in to the boiler. For example the pump, normally installed remote from the boiler, in built in; so is the expansion vessel, which replaces the feed/expansion tank often installed in the loft. The safety valve, the automatic air vent and even the programmer are also included.
- 24. With these components built in installation time is reduced significantly, fewer materials are required, costs are reduced and servicing is simplified. The added bonus of a "dry loft" removes the worry of any leak or frost damage to tanks and pipe work. Back Boilers Back boilers can be fuelled by gas, oil or solid fuel. All require a lined, natural- draught open flue to expel the potentially harmful gases. Solid fuel back boilers can only provide hot water when the fire which heats the house is lit. Gas and oil back boilers however can work independently of the fire front so are able to provide hot water all year round. An electric immersion heater can be used as with a conventional boiler. Condensing Boilers A Condensing boiler uses modern technology to maximise the fuel efficiency of either a conventional or combination system. The boiler is designed so that the cooler water returning from the radiators is passed through a secondary heat exchanger to be warmed by the hot flue gases which are normally expelled in to the air. The warmer water is then sent back to the radiators.
- 25. It is known as a Condensing boiler because the water from these flue gases 'condenses' in the secondary heat exchanger and drains away at the bottom of the boiler. Although condensing boilers will become increasingly popular as dramatic savings can be made on fuel consumption they are at present still in their infancy and may be more prone to breakdowns. They are also more expensive to buy although grants can often be obtained to assist with the extra cost. Storage Tanks Boilers with a storage tank (hot water cylinder) are better capable of coping with the demands of multiple use and can deliver water at a high temperature and at a high flow rate too. Unvented tanks allow mains pressure water delivery, rather than relying on gravity as traditional open vented systems do. BATTERIES INTRODUCTION: In isolated systems away from the grid, batteries are used for storage of excess solar energy converted into electrical energy. The only exceptions are isolated sunshine load such as irrigation pumps or drinking water supplies for storage.
- 26. In fact for small units with output less than one kilowatt. Batteries seem to be the only technically and economically available storage means. Since both the photo-voltaic system and batteries are high in capital costs. It is necessary that the overall system be optimized with respect to available energy and local demand pattern. To be economically attractive the storage of solar electricity requires a battery with a particular combination of properties: (1) Low cost (2) Long life (3) High reliability (4) High overall efficiency (5) Low discharge (6) Minimum maintenance (A) Ampere hour efficiency (B) Watt hour efficiency We use lead acid battery for storing the electrical energy from the solar panel for lighting the street and so about the lead acid cells are explained below.
- 27. LEAD-ACID WET CELL: Where high values of load current are necessary, the lead-acid cell is the type most commonly used. The electrolyte is a dilute solution of sulfuric acid (H₂SO₄). In the application of battery power to start the engine in an auto mobile, for example, the load current to the starter motor is typically 200 to 400A. One cell has a nominal output of 2.1V, but lead-acid cells are often used in a series combination of three for a 6-V battery and six for a 12-V battery. The lead acid cell type is a secondary cell or storage cell, which can be recharged. The charge and discharge cycle can be repeated many times to restore the output voltage, as long as the cell is in good physical condition. However, heat with excessive charge and discharge currents shortends the useful life to about 3 to 5 years for an automobile battery. Of the different types of secondary cells, the lead-acid type has the highest output voltage, which allows fewer cells for a specified battery voltage. CONSTRUCTION: Inside a lead-acid battery, the positive and negative electrodes consist of a group of plates welded to a connecting strap.
- 28. The plates are immersed in the electrolyte, consisting of 8 parts of water to 3 parts of concentrated sulfuric acid. Each plate is a grid or framework, made of a lead- antimony alloy. This construction enables the active material, which is lead oxide, to be pasted into the grid. In manufacture of the cell, a forming charge produces the positive and negative electrodes. In the forming process, the active material in the positive plate is changed to lead peroxide (pbo₂). The negative electrode is spongy lead (pb).
- 30. Automobile batteries are usually shipped dry from the manufacturer. The electrolyte is put in at the time of installation, and then the battery is charged to from the plates. With maintenance-free batteries, little or no water need be added in normal service. Some types are sealed, except for a pressure vent, without provision for adding water. The construction parts of battery are shown in figure. CHEMICAL ACTION: Sulfuric acid is a combination of hydrogen and sulfate ions. When the cell discharges, lead peroxide from the positive electrode combines with hydrogen ions to form water and with sulfate ions to form lead sulfate. Combining lead on the negative plate with sulfate ions also produces he sulfate. There fore, the net result of discharge is to produce more water, which dilutes the electrolyte, and to form lead sulfate on the plates. As the discharge continues, the sulfate fills the pores of the grids, retarding circulation of acid in the active material. Lead sulfate is the powder often seen on the outside terminals of old batteries. When the combination of weak electrolyte and sulfating on the plate lowers the output of the battery, charging is necessary.
- 31. On charge, the external D.C. source reverses the current in the battery. The reversed direction of ions flows in the electrolyte result in a reversal of the chemical reactions. Now the lead sulfates on the positive plate reactive with the water and sulfate ions to produce lead peroxide and sulfuric acid. This action re-forms the positive plates and makes the electrolyte stronger by adding sulfuric acid. At the same time, charging enables the lead sulfate on the negative plate to react with hydrogen ions; this also forms sulfuric acid while reforming lead on the negative plate to react with hydrogen ions; this also forms currents can restore the cell to full output, with lead peroxide on the positive plates, spongy lead on the negative plate, and the required concentration of sulfuric acid in the electrolyte.
- 33. The chemical equation for the lead-acid cell is Charge Pb + pbO₂ + 2H₂SO₄ 2pbSO₄ + 2H₂O Discharge On discharge, the pb and pbo₂ combine with the SO₄ ions at the left side of the equation to form lead sulfate (pbSO₄) and water (H₂O) at the right side of the equation. One battery consists of 6 cells, each have an output voltage of 2.1V, which are connected in series to get an voltage of 12V and the same 12V battery is connected in series, to get an 24 V battery. They are placed in the water proof iron casing box. CARING FOR LEAD-ACID BATTERIES: Always use extreme caution when handling batteries and electrolyte. Wear gloves, goggles and old clothes. “Battery acid” will burn skin and eyes and destroy cotton and wool clothing. The quickest way of ruin lead-acid batteries is to discharge them deeply and leave them stand “dead” for an extended period of time. When they discharge, there is a chemical change in the positive plates of the battery.
- 34. They change from lead oxide when charge out lead sulfate when discharged. If they remain in the lead Sulfate State for a few days, some part of the plate dose not returns to lead oxide when the battery is recharged. If the battery remains discharge longer, a greater amount of the positive plate will remain lead sulfate. The parts of the plates that become “sulfate” no longer store energy. Batteries that are deeply discharged, and then charged partially on a regular basis can fail in less then one year. Check your batteries on a regular basis to be sure they are getting charged. Use a hydrometer to check the specific gravity of your lead acid batteries. If batteries are cycled very deeply and then recharged quickly, the specific gravity reading will be lower than it should because the electrolyte at the top of the battery may not have mixed with the “charged” electrolyte. Check the electrolyte level in the wet-cell batteries at the least four times a year and top each cell of with distilled water. Do not add water to discharged batteries. Electrolyte is absorbed when batteries are very discharged. If you add water at this time, and then recharge the battery, electrolyte will overflow and make a mess. Keep the top of your batteries clean and check that cables are tight. Do not tighten or remove cables while charging or discharging. Any spark around batteries can cause a hydrogen explosion inside, and ruin one of the cells, and you.
- 35. On charge, with reverse current through the electrolyte, the chemical action is reversed. Then the pb ions from the lead sulfate on the right side of the equation re-form the lead and lead peroxide electrodes. Also the SO₄ ions combine with H₂ ions from the water to produce more sulfuric acid at the left side of the equation. CURRENT RATINGS: Lead-acid batteries are generally rated in terms of how much discharge currents they can supply for a specified period of time; the output voltage must be maintained above a minimum level, which is 1.5 to 1.8V per cell. A common rating is ampere-hours (A.h.) based on a specific discharge time, which is often 8h. Typical values for automobile batteries are 100 to 300 A.h. As an example, a 200 A.h battery can supply a load current of 200/8 or 25A, used on 8h discharge. The battery can supply less current for a longer time or more current for a shorter time. Automobile batteries may be rated for “cold cranking power”, which is related to the job of starting the engine. A typical rating is 450A for 30s at a temperature of 0 degree F. Note that the ampere-hour unit specifies coulombs of charge. For instance, 200 A.h. corresponds to 200A*3600s (1h=3600s). the equals 720,000 A.S, or coulombs. One ampere-second is equal to one coulomb.
- 36. Then the charge equals 720,000 or 7.2*10^5ºC. To put this much charge back into the battery would require 20 hours with a charging current of 10A.The ratings for lead- acid batteries are given for a temperature range of 77 to 80ºF. Higher temperature increase the chemical reaction, but operation above 110ºF shortens the battery life. Low temperatures reduce the current capacity and voltage output. The ampere- hour capacity is reduced approximately 0.75% for each decreases of 1º F below normal temperature rating. At 0ºF the available output is only 60 % of the ampere-hour battery rating. In cold weather, therefore, it is very important to have an automobile battery unto full charge. In addition, the electrolyte freezes more easily when diluted by water in the discharged condition. SPECIFIC GRAVITY: Measuring the specific gravity of the electrolyte generally checks the state of discharge for a lead-acid cell. Specific gravity is a ratio comparing the weight of a substance with the weight of a substance with the weight of water. For instance, concentrated sulfuric acid is 1.835 times as heavy as water for the same volume. Therefore, its specific gravity equals 1.835. The specific gravity of water is 1, since it is the reference.
- 37. In a fully charged automotive cell, mixture of sulfuric acid and water results in a specific gravity of 1.280 at room temperatures of 70 to 80ºF. as the cell discharges, more water is formed, lowering the specific gravity. When it is down to about 1.150, the cell is completely discharged. Specific-gravity readings are taken with a battery hydrometer, such as one in figure (7). Note that the calibrated float with the specific gravity marks will rest higher in an electrolyte of higher specific gravity. The decimal point is often omitted for convenience. For example, the value of 1.220 in figure (7) is simply read “twelve twenty”. A hydrometer reading of 1260 to 1280 indicates full charge, approximately 12.50 are half charge, and 1150 to 1200 indicates complete discharge. The importance of the specific gravity can be seen from the fact that the open- circuit voltage of the lead-acid cell is approximately equal to V = Specific gravity + 0.84 For the specific gravity of 1.280, the voltage is 1.280 = 0.84 = 2.12V, as an example. These values are for a fully charged battery.
- 38. CHARGING THE LEAD-ACID BATERY: The requirements are illustrated in figure. An external D.C. voltage source is necessary to produce current in one direction. Also, the charging voltage must be more than the battery e.m.f. Approximately 2.5 per cell are enough to over the cell e.m.f. so that the charging voltage can produce current opposite to the direction of discharge current. Note that the reversal of current is obtained just by connecting the battery VB and charging source VG with + to + and –to-, as shown in figure. The charging current is reversed because the battery effectively becomes a load resistance for VG when it higher than VB. In this example, the net voltage available to produce charging currents is 15- 12=3V. A commercial charger for automobile batteries is essentially a D.C. power supply, rectifying input from the AC power line to provide D.C. output for charging batteries. Float charging refers to a method in which the charger and the battery are always connected to each other for supplying current to the load. In figure the charger provides current for the load and the current necessary to keep the battery fully charged. The battery here is an auxiliary source for D.C. power.
- 39. It may be of interest to note that an automobile battery is in a floating-charge circuit. The battery charger is an AC generator or alternator with rectifier diodes, driver by a belt from the engine. When you start the car, the battery supplies the cranking power. Once the engine is running, the alternator charges he battery. It is not necessary for the car to be moving. A voltage regulator is used in this system to maintain the output at approximately 13 to 15 V. The constant voltage of 24V comes from the solar panel controlled by the charge controller so for storing this energy we need a 24V battery so two 12V battery are connected in series. It is a good idea to do an equalizing charge when some cells show a variation of 0.05 specific gravity from each other. This is a long steady overcharge, bringing the battery to a gassing or bubbling state. Do not equalize sealed or gel type batteries. With proper care, lead-acid batteries will have a long service life and work very well in almost any power system. Unfortunately, with poor treatment lead-acid battery life will be very short.
- 40. INVERTER INTRODUCTION: The process of converting D.C. into A.C. is known as INVERSION. In other words, we may define it as the reverse process of rectification. The device, which performs this process, is known as an INVERTOR. Inversion is, by no means, a recent process. In olden days gas-filled tubes and vacuum tubes were used to develop inverters. Thyratron inverter is popularly used as a large power device. Vacuum tube inverters were generally used for high-frequency applications. Some of the main disadvantages of the tube as well as the mercury pool type inverters are: 1. They are very costly 2. They are very big in size and heavy in weight 3. They have very poor efficiency 4. The voltage drop across these devices is very high 5. They are less accurate 6. They are very slow in response, etc. The basic principle of an inverter can be explained with the help of a simple circuit, as shown in figure. If switch S is connected alternately to position 1 and 2 at a rapid speed and if S is not kept closed to any of the two positions (1 and 2) for too long, and then an alternating voltage will appear across the primary winding. This can be explained by the direction of the current flow in the primary winding.
- 41. Although the voltage applied is D.C. in nature, the direction of current flow in the primary winding when S is connected to position 1 is from top to bottom whereas when S is connected at position 2, the current flows from bottom to top. This change in the direction of current flow in the primary winding gives rise to an alternating voltage in it. The frequencies of this alternating voltage will depend on how rapidly the switch (S) positions are interchanged. This alternating voltage in the primary winding will induce an alternating emf in the secondary winding, which will act as the A.C. output. With the development of semi-conductor devices, a lot of improvements to took place in the design of inverter circuits. Transistor being a fast-switching device was used as a switch for developing low and medium power inverters. LAMP STEAM P.M.D.C. GENERATOR BATTERY INVERTOR
- 42. CIRCUIT DIAGRAM IN 4007 IN 4007 9V-0-9V CHARGER POLARITY PROTECTOR + - 100μF CHARGING ON/OFF 50V INDICATOR LED SWITCH 12 V / 7.5 A.H BATTERY 220Ω IN 4007 A.C MAINS 100µF/50V RF 220Ω CHOKE 100µF/25V 0.1µF 120Ω DISCHARGE INDICATOR INVERTER BC 547 10k TRANSFORMER 2N3055 POWER O/P 4.7µF 560Ω 100µF/25V CUM OSCILATOR 40 W TUBE LIGHT
- 43. Working principle:- • CHARGING CIRCUIT:- The step down transformer is used to reduce the supply voltages in to 9-0-9V. This signal is rectified by the rectifier unit with the help of diodes. The Capacitor is used to filter the rectified signal and this signal is given to the battery input supply. • INVERTING CIRCUIT:- The inverter circuit is activated when the switch is in on condition. The discharge indication is given with the help of discharge LED. The variable resister is used to varying the intensity of the tube light. The capacitors and transistors are used to amplifier cum oscillator circuit. This will produce the a.c signal and this signal is given to the inverter transformer. The inverter output is given to the load. PERMANENT MAGNET D.C. GENERATOR: Voltage Production DC Circuits, that there are three conditions necessary to induce a voltage into a conductor. 1. A magnetic field 2. A conductor 3. Relative motion between the two.
- 44. A DC generator provides these three conditions to produce a DC voltage output. Theory of Operation A basic DC generator has four basic parts: (1) A magnetic field; (2) A single conductor, or loop; (3) A commutator; and (4) Brushes The magnetic field may be supplied by either a permanent magnet or an electromagnet. For now, we will use a permanent magnet to describe a basic DC generator.
- 45. Basic Operation of a DC Generator A single conductor, shaped in the form of a loop, is positioned between the magnetic poles. As long as the loop is stationary, the magnetic field has no effect (no relative motion). If we rotate the loop, the loop cuts through the magnetic field, and an EMF (voltage) is induced into the loop. When we have relative motion between a magnetic field and a conductor in that magnetic field, and the direction of rotation is such that the conductor cuts the lines of flux, an EMF is induced into the conductor. The magnitude of the induced EMF depends on the field strength and the rate at which the flux lines are cut. The stronger the field or the more flux lines cut for a given period of time, the larger the induced EMF. Eg = KFN where Eg = generated voltage K = fixed constant F = magnetic flux strength N = speed in RPM
- 46. The direction of the induced current flow can be determined using the "left-hand rule" for generators. This rule states that if you point the index finger of your left hand in the direction of the magnetic field (from North to South) and point the thumb in the direction of motion of the conductor, the middle finger will point in the direction of current flow. For example, the conductor closest to the N pole is traveling upward across the field; therefore, the current flow is to the right, lower corner. Applying the left-hand rule to both sides of the loop will show that current flows in a counter-clockwise direction in the loop. DC GENERATOR CONSTRUCTION Output Voltage-vs-Load Current for Shunt-Wound DC Generator the shunt- wound generator, running at a constant speed under varying load conditions, has a much more stable voltage output than does a series-wound generator. Some change in output voltage does take place. This change is caused by the fact that, as the load current increases, the voltage drop (I R) across the armature coil increases, causing output voltage to decrease.
- 47. As a result, the current through the field decreases, reducing the magnetic field and causing voltage to decrease even more. If load current is much higher than the design of the generator, the drop in output voltage is severe. For load current within the design range of the generator, the drop in output voltage is minimal. LIGHTING LOAD: FLUORESCENT TUBES: INTRODUCTION: This type of lamps is a low-pressure mercury vapor discharge lamp. Fluorescent lighting has a great advantage over other light source in many applications. It is possible to achieve quite high lighting intensities without excessive temperature rises. The efficiency of fluorescent lamp is about 40 lumens per watt, about three times the efficiency of an equivalent tungsten lamp. The average life of a fluorescent lamp is about 4,000 working hours. CONSTRUCTION: The fluorescent tube consists of a glass tube and 0.6 meter, 1.2 meters and 1.5 meters in length. The inside surface of the tube is coated with a thin layer of fluorescent material in the form of a powder.
- 48. Various fluorescent materials give different color light. By mixing the various powders light of any desired color including daylight can be obtained. The glass tube of the fluorescent lamp is provided at both ends with bipin caps and oxide coated tungsten filaments. The tube contains organ gas with a small quantity of mercury under low pressure. Even with organ gas the discharge will not start at ordinary main voltage. A choke and a starter switch are therefore incorporated in the circuit of the tube lamp to give a momentary high voltage across the tube to start the discharge. The choke is connected in series with the tube the starter is connected across tube. The circuit is suddenly opened at the starter, the flux around the choke collapse causing a kick of about 1000V. This voltage is applied across the two electrodes and sufficient to start the discharge of the tube. During the steady operation of this lamp the voltage across the tube drops to about 150 volts. This voltage is sufficient to maintain the discharge of the tube. During the steady operation of this lamp, the voltage across the tube drops to about 150 volts. This voltage is sufficient to maintain the discharge. The choke in series with the tube now acts as a stabilizer. A capacitor is connected across the circuit it improve the power factor.
- 50. CHAPTER-5 WORKING PRINCIPLE The block diagram of steam power plant is shown in figure, it consist of a boiler unit, 12 voltage battery, an inverter and a florescent lamp. As we studied from the generator gives a D.C. output of 12V this D.C. output is not always constant there is some variation in this D.C. output this cannot be given to the battery storage it may weaken the life of the battery. So in order to get constant D.C. output and also to avoid the reverse flow of current to the panel in the case of no load a charge controller have been used this help us to allow only the constant voltage of 12V D.C. to the battery and also it act as an blocking diode and protect the motor principle. By this way the battery gets charged then this D.C. storage is given to an inverter this inverter inverts 12V D.C. to input in to AC output, step upped in to 230V.The 230V AC supply is given to the supply to the lamp. The lamp used for street lighting is 230V, 50 Hz, single-phase supply. LAMP BOILER UNIT D.C GENERAT OR BATTER Y INVERTOR
- 51. CIRCUIT DIAGRAM IN 4007 IN 4007 9V-0-9V CHARGER POLARITY PROTECTOR + - 100μF CHARGING ON/OFF 25V INDICATOR LED SWITCH 12 V / 7.5 A.H BATTERY 220Ω IN 4007 A.C MAINS RF 4K7 220Ω CHOKE 220Ω 1K 4K7 DISCHARGE 1K INDICATOR INVERTER D882 BC 547 BC 547 2K BC 547 AUTO OFF VR 1K2 3K3 pF TRANSFORMER D 882 POWER O/P 220Ω 330Ω 2KV CUM OSCILATOR 11 W /11S CFL TUBE
- 54. ADVANTAGES AND DISADVANTAGES Steam is produced by the simply the flow lamp This is a Non-conventional system Battery is used to store the generated power High pressure steam produced DISADVANTAGES • Only applicable for the particular place. • Initial cost of this arrangement is high. • Input Fuel supply needed CHAPTER-6 ADVANTAGES
- 56. APPLICATIONS Direct heat applications Mechanical motion derived from water power can be used to drive heat pumps or to produce heat from the friction of solid materials, or by the churning of water or other fluids, or in other cases, by the use of centrifugal or other types of pumps in combination with restrictive orifices that produces heat from friction and turbulence when the working fluid flows through them. This heat may then be stored in materials having a high heat capacity, such as water, stones, eutectic salts, etc., A home heating system that uses a water powered pump and a restrictive orifice to derive direct heat for a building, without first generating electricity also has been developed. Electric Generation Applications: Water power can be used in centralized utility applications to drive synchronous A.C. electrical generators. In such applications the energy is fed directly into power networks through voltage step-up transformers. CHAPTER-7
- 57. This unit can be integrated with existing hydro electrical networks and used in a “water-saver” mode of operation. When the water is blowing, electrical an amount equal to the being can reduce generation at the hydroelectric plants in the network produced by this unit. Thus, the water turbines supply part of the network load that is ordinarily produced by the hydroelectric generators. Under these conditions some of the water that would have been used by the hydroelectric plant to supply the load is saved in the reservoir and made available for later use when the water is not blowing.
- 59. CHAPTER-8 LIST OF MATERIALS SL. NO. NAME OF THE PARTS MATERIAL QUANTITY 1 Boiler tank Mild Steel 1 2 Gate Valve Brass 1 3 Generator (D.C 12 V) Aluminium 1 4 Battery (12 V) Lead-acid 1 5 Inverter Electronic PCB 5 meter 6 Frame Stand Mild Steel 1 7 Hose Collar Brass 2 8 Turbine blade Mild Steel 1 9 Connecting Wire Cu 2 meter -------------------------------------------------------------------------------------- Chapter-9 --------------------------------------------------------------------------------------
- 61. SL. NO. NAME OF THE PARTS MATERIAL QUANTITY AMOUNT (RS) 1 Boiler tank Mild Steel 1 2 Gate Valve Brass 1 3 Generator (D.C 12 V) Aluminium 1 4 Battery (12 V) Lead-acid 1 5 Inverter Electronic PCB 5 meter 6 Frame Stand Mild Steel 1 7 Hose Collar Brass 2 8 Turbine blade Mild Steel 1 9 Connecting Wire Cu 2 meter TOTAL = 2. LABOUR COST LATHE, DRILLING, WELDING, GRINDING, POWER HACKSAW, GAS CUTTING: Cost = 3. OVERHEAD CHARGES The overhead charges are arrived by “Manufacturing cost” Manufacturing Cost = Material Cost + Labour cost = = Overhead Charges = 20% of the manufacturing cost =
- 62. TOTAL COST Total cost = Material Cost + Labour cost + Overhead Charges = = Total cost for this project = -------------------------------------------------------------------------------------- Chapter-10 --------------------------------------------------------------------------------------
- 64. A strong multidiscipline team with a good engineering base is necessary for the Development and refinement of advanced computer programming, editing techniques, diagnostic Software, algorithms for the dynamic exchange of informational different levels of hierarchy. Simulation techniques are suitable for solving some of the problems. But a good quantitative model and a test set-up will help to understand the systems. This project work has provided us an excellent opportunity and experience, to use our limited knowledge. We gained a lot of practical knowledge regarding, planning, purchasing, assembling and machining while doing this project work. We feel that the project work is a good solution to bridge the gates between institution and industries. We are proud that we have completed the work with the limited time successfully. The STEAM POWER PLANT is working with satisfactory conditions. We are able to understand the difficulties in maintaining the tolerances and also quality. We have done to our ability and skill making maximum use of available facilities. In conclusion remarks of our project work, let us add a few more lines about our impression project work. Thus we have developed a “STEAM POWER PLANT” which helps to know how to achieve low cost steam power plant model. By using more techniques, they can be modified and developed according to the applications.
- 66. BIBLIOGRAPHY RAI. G.D. “NON CONVENTIONAL ENERGY SOURCES”, KHANNA PUBLISHERS, DELHI. RAMESH. R, UDAYA KUMAR, K.ANANDAKRISHNAN “RENEWABLE ENERGY TECHNOLOGIES”, NAROSA PUBLISHING HOUSE, MADRAS. A.K.SAWHNEY. “A TEXT BOOK OF ELECTRICAL, ELECTRONICS, INSTRUMENTATION AND MEASUREMENTS” B.L.THERJA, A.K. THERAJA. “A TEXT BOOK OF ELECTRICAL TECHNOLOGY” G.R.NAGPAL. “POWER PLANT ENGINEERING” KHANNA PUBLISHERS, DELHI.