The working principle Paiton units 7 and 8 in general is the combustion of coal in the boiler for heating water and turning water into a very hot steam which is used to drive turbines and generate electricity from the coil's magnetic field in the generator. The system settings used in the power plant uses a closed loop regulating system, where the water used for some process is the same water rotation, only be added if the existing level of less than set point. Shape are changed, to a certain level of water tangible, but at a level other tangible steam.
The process begins with water being pumped into the condenser, then the condenser is pumped to the polisher to be processed for corrosion and precipitation is lost, after it is pumped to the Feed Water Heater 1, 2, 3 and 4 to be heated and then poured into Daerator to eliminate gas - O2 and CO2 is then pumped back into the Feed Water Heater 6, 7, 8 which would then be forwarded in the economizer to elevated temperature and then headed to the steam drum to separate between the steam and water, after which the superheated steam which is going through the First Super Heater, Secondary Super Heater and form a super heated steam that will be used to turn the HP turbine so that the pressure and temperature will drop, so SH steam is necessary reheating which occurs at Re Heater, Re Heater from this SH Steam will be returned to Play IP and LP Turbine. This will occur within the turbine thermal energy conversion from steam into mechanical energy that causes the rotating turbine rotor rotates. This rotor rotation that will move the generator and finally by the generator mechanical energy is converted into electrical energy.
1. COAL HANDLING
Coal is the main fuel Paiton Unit 7 and 8. Coal is used in the form of coal, Adaro, Arutmin, KIDECO with ash content of 1.5%, coal was taken from a coal mine in southern Kalimantan and will continue disuply during operation. Shipping coal to the plant carried out by using two ships with a capacity of around 43,000 tonnes, which would then be accommodated in the Coal Pile with a capacity of 670,000 tons for subsequent use as fuel. Prior to use as fuel, coal will go through some process that is Stacking, Reclaiming and Processing. But it will only implement the Coal Handling and Reclaming stacking process, while for the processing included in the boiler operation and will be described in further discussion. Stacking is the process penumpukana coal from ships. While processing the coal handling system of Shiloh until ready for use in boilers.
Stacking
Stacking is the process of moving coal from ships to the Coal Pile. Some of the terms in such Stacking
a. Jetty
Jetty is a pier or dock where ships carrying coal in Paiton Unit 7 and 8. The depth of this pier is 18 m from the seabed, allowing large ships docked. In Unit 7 and there are two jetties Jetty Jetty A and B. Each Jetty has four pieces Doc Hopper Cars whose function is to move coal from ships into the Conveyor Belt. Doc Hopper Cars posissinya can be changed in accordance with the ship's position, it is controlled by the operator in Coal Unloading Control building (CUCB).
b. Conveyor Belt
Conveyor Belt-shaped kind of large belt made of rubber which moves through the Head and Tail Pulley Pulley, both of which serve to move the Conveyor Belt and Pulley Tansioning peregang that serves as a conveyor belt. Conveyor Belt To support the weight of coal are transported along with idler mounted at a certain distance between the Head and Tail Pulley Pulley. Rotating bearing idler is passed by the Conveyor Belt. Coal is transported by conveyor poured from a tub launcher (Chute) Tail Pulley tip and then move toward the direction of Head Pulley. Typically, the cargo of coal will fall into a bath of other launchers, located under the Head Pulley to be forwarded to another conveyor or into storage tanks. In each branch between Conveyor one another denagn associated with Transfer House, other than that on the conveyor belt also added some accessories that aim to increase flexibility, among others:
1. Sample Takers
Done automatically, if it detected the existence of metal in coal samplers immediately stopped.
2. Metal Detector
It is a tool to detect the presence of metals in coal are mixed in the delivery process.
3. Magnetic Separator
To separate the metals contained in coal in the process of delivery.
4. Belt Scale
To determine the amount of weight tonnase coal transported by Conveyor Belt.
5. Dust Supasion
Serves to:
- Water Polution controller
- Spraying ait on coal
- Saves coal dust so as not to be
- Block the occurrence of sparks due to heat from the coal dust.
c. Reclaiming
Reclaming is the process of taking coal from Coal Pile and distribute to Shiloh. Some terms in reclaiming among others:
d. Coal Pile
There are four regions Coal Pile, in succession from north to south are:
1. Inactive
- Area: 57,562 m2
- Height: 17 m
- Perimeter Length: 1176 m
- Length of the toe: 21 m
- Usable Volume: 768,638 m3
- Bedding Coal volume: 28,781 m3
- Total capacty in tonnage is
(768638 + 28781) x 0.83 = tonnes 66185t
- Maximum working capacity in tonnage is 768,638 x 0.83 = 637969t
2. On 'A'
- Area: 10,260 m2
- Height: 9m
- Perimeter Length: 616 m
- Length of the toe: 12 m
- Usable Volume: 59,076 m3
- Bedding Coal volume: 5130 m3
- Total capacty in tonnage is
(59076 + 5130) x 0.83 = tonnes 53290t
- Maximum working capacity in tonnage is
59 076 x 0.83 = 49 033 t
3. On 'B'
- Area: 10,184 m2
- Height: 9 m
- Perimeter Length: 612 m
- Length of the toe: 12 m
- Usable Volume: 58,608 m3
- Bedding Coal volume: 5092 m3
- Total capacty in tonnage is
(58068 + 5092) x 0.83 = 52871t tons
- Maximum working capacity in tonnage is
58 608 x 0.83 = 48644t
4. On 'C'
- Area: 10,184 m2
- Height: 9 m
- Perimeter Length: 612 m
- Length of the toe: 12 m
- Usable Volume: 58,608 m3
- Bedding Coal volume: 5092 m3
- Total capacty in tonnage is
(58068 + 5092) x 0.83 = 52871t tons
- Maximum working capacity in tonnage is
58 608 x 0.83 = 48644t
5. On 'D'
- Area: 6992m2
- Height: 9 m
- Perimeter Length: 480 m
- Length of the toe: 12 m
- Usable Volume: 37,008 m3
- Bedding Coal volume: 3496 m3
- Total capacty in tonnage is
(37008 + 5092) x 0.83 = 40,504 tons t
- Maximum working capacity in tonnage is
37 008 x 0.83 = 30716t
6. Summary:
- Total tonnage of coal bedding: 39,395 tonnes
- Total volume of all 4 active stockpiles: 177,037 tonnes
- Total volume of inactive stockpiles: 637,969 tonnes
- Theoreticaal maximum total: 854 401 tonnes
In the Coal Pile, hoarding and retrieval process of coal carried by an instrument called a stacker / Reklaimer. This tool is a complex conveyor and mounted on a structure that can move. In the process of accumulation, stackers deliver coal through an arm that can be set to always quiet place, so that the coal that spilled through the arm it will form a high embankment, when the arm moves back and forth then the pile that will be produced into a neat pile and elongated. At the time of collection, Reclaiming Buckets in the stacker will spin and then scrape coal poured into the Conveyor Belt to be brought to installation. As with the process of accumulation, Reclaiming Buckets can also be arranged aagar remain quiet place or back and forth to scrape coal.
e. Coal Silo
There are six pieces Coal Silo namely A, B, C, D, E and F. Silo filling is done by using a conveyor belt associated with Tripper, pengopersiannya Coal carried by the operator in handling the Control Building (CHCB). Shiloh is a place to accommodate the coal bunkers at the plant which is then used as fuel in boilers. The volume of a silo of 600 tons, recharging is done every silo volume is less than 30-40%. From the coal silo inserted using the Coal Feeder Pulverizer, Pulverizer coal from this that will be used for combustion in boilers.
2. BOILER
In the power plant, energy is continuously converted from one form to another to generate electricity. Components that initiate change and energy flowing is called the boiler. Definition of the boiler itself as a component in the power plant is a closed vessel which could efficiently convert water into steam with the help of heat from coal combustion process. If operated correctly, the boiler can efficiently convert large volumes of water into steam is very hot in greater volume.
Type of boiler used in units 7 and 8 are Drum Type Boilers, which allows the circulation of some of the water in the boiler continuously. Drum Type Boiler Operating an efficient and secure highly dependent on the constant circulation of water in some components of the steam circuit, including economizer, Steam Boiler Drum and Circulaating Water Pump.
a. Economizer
Economizer function to increase the temperature of water (preheated) before entering the boiler for steam then flows into the drum, these components are in a boiler that consists of a series of pipes (tubes) that receives water from the inlet.
Heat source required by the tool comes from the exhaust gas in the boiler. Water flows in the pipes, while outside the hot gas flow coming from the combustion boiler. Furthermore, hot steam is used to heat water so that its temperature increases.
Economizer for preheating is important, because:
1. This can increase the efficiency of the boiler as a whole, because the existing heat in the steam can be used to conduct business.
2. By heating the water before the water is converted into steam in the boiler, means that facilitate the boiler, just a little heat that needs to be added.
3. Warm water will only reduce the Thermal Shock on Boiler.
b. Steam Drum
Serves to store water in large volumes and to separate the steam from the water after the heating process that occurs in the boiler. In umunm, there are four basic types of pipe connections associated with Steam Drum, namely:
1. Feed Water Pipe
Functioning drain water from the economizer to the Distribution Pipe length exactly the same as Steam Drum. Distribute Pipe drain water from the economizer function evenly throughout the Steam Drum.
2. Downcomer or pipe down
Placed along the base of Steam Drum with the same distance from each other. These pipes drain the water from the steam drum to the boiler circulating pump. Water Boiler circulating Pump (BWCP) is used to pump water from Downcomer and circulate it to the waterwall which water is heated by combustion in boilers and sent back to the Steam Drum.
3. Waterwall Pipe
Located on both sides of Steam Drum and the small pipes are lined up vertically in the boilers, each pipe connected to one another to form a continuous sheath in the boiler. Construction like this is called the membrane construction. Waterwall duty to receive and drain water from the boiler circulating pump and then heated in a boiler and poured into Steam Drum
4. Steam Outlet Pipe
It is the last connection, placed at the top to allow for Saturated Steam Drum Steam Drum Steam headed out of the superheater.
In Steam Drum, Saturated Steam will be separated and forwarded for further warming in the superheater, while the water remains in the steam drum and poured into Down Comer, from here the process will begin again.
In addition to these pipes, there are also blow down pipe which is located at the bottom of Steam Drum, just below the water surface. When water turns to steam, water impurities will remain in the water in the Steam Drum. If such a high concentration of impurities, the purity of steam coming out of Steam Drum will be affected and will carry over to the Super Heater or to the turbine. Pipe blow down water will remove some dirt from the surface of the Steam Boiler Drum, and running it so it can reduce the concentration of impurities in the water boiler, and ultimately to maintain Turbine Super Heater and kept clean.
3. HEATER
a. Superheater
Boiler superheater is a collection pipe located street flow of hot gases of combustion. The heat of this gas is transferred to Saturated Steam in superheater tube, so that turned into a super heated steam.
Superheater, there are two parts, namely Primary and Secondary superheater superheater. Primary superheater is bypassed by the first heating Saturate Steam Steam after exiting the drum, after which the newly passed Secondary superheater and a super heated steam. SH Steam will be streamed to rotate High Presure Turbine, and then pressure and temperature will fall.
b. Re-Heater
After pressure and temperature SH SH Steam Steam down then it will be returned to the boiler for reheating. Reheating takes place at the Boiler-called Re-heater which is a collection pipe heat boiler fed from the combustion gases such as superheater. So Re-Heater SH serves to raise the temperature of steam without affecting the pressure. At the Re heater, SH Steam will be returned to play Intermediate Presure Turbine (IP) and Low Presure Turbine (LP).
Air Pre-Heater
Air Pre-Heater is an instrument that works rotating system with low rotation and serves to heat the combustion air before it is sent to the furnace. Heater combustion air is taken from the exhaust gases of combustion from the furnace that is channeled through the Air Pre-heater before being discharged into the Chimney.
4. FEED WATER HEATER
There are 8 Feed Water Heater, namely:
a. Feed Water heater 1
Located at the bottom Condensor, functions to heat the water coming out of the Condensor. The heat comes from extration LP Turbine.
b. Feed Water Heater 2, 3, and 4
Its function is to heat the water before the water enters Daerator. The heat comes from extration LP Turbine.
c. Feed Water Heater 5
Located above Daerator. The heat comes from extration IP Turbine.
d. Feed Wter Heater 6 A-B, 7 A-B and 8 A-B
Its function is to heat water that will enter the economizer, to FW Heater 6 and 7 AB AB heat used comes from IP Turbine extration while for FW Heater 8 AB heat used comes from extration HP Turbine.
5. Furnace
There are four conditions of combustion of fuel, oxygen, heat and chemical reactions. However, for in Boilers need for additional requirements for combustion in boilers are working with the turbulence and time efficient. Sufficient time should be sought for combustible mixture to burn completely. The flow of fuel in the boiler must be slow enough to allow enough time for complete combustion, if no combustible materials will be collected in the boiler or chimney and cause a danger of explosion. Danger of explosion prevented by proper design Boilers, Boiler should be large enough to slow the flow of air, so before leaving the boiler to burn fuel properly.
a. ID Fan, FD Fan Fan and PA
Combustion air there are two kinds, namely Primary Air (primary air) and Secondary Air (secondary air). Primary air supplied by the Primary Air Fan (Fan PA), which is exhaled into the coal mill equipment (Pulverizer) then together with coal powder poured into the furnace to be burned (chemical reaction). Mixing of coal and air assisted by the regulator remains Dumper air stirrer causing turbulence that enables efficient combustion. Turbulence refers to air movement within the furnace, this movement is necessary because it can improve the mixing of air and fuel.
Primary air is not sufficient to meet the needs of turbulence for mixing the fuel properly or satisfy the need for oxygen for complete combustion. For that needed supply of secondary air generated by the FD Fan with ID Fan. Boilers that work with negative pressure or under atmospheric pressure is always equipped with the Force Draft Fan (FD Fan) and Induced Draft Fan (ID Fan). Boiler is called the Balanced-Draft Furnace with a fan pull is balanced.
b. Pulverizer
Chunks - chunks of coal like stone must be crushed into fine-grained easy for coal mixed with air. Pulverizer is a tool to grind the coal so that it becomes smooth and then together with the primary air will be channeled to the furnace. Another function of the Pulverizer is to dry the coal so easily crushed and burned, and to classify or filter the coal to ensure that the coal into the boiler is really smooth. Coal is not millstones will come out through a hole and placed in Pyrites Hopper and then discarded.
In the use of Pulverizer to note is the temperature of primary air, the temperature is too high to turn coal from the Pulverizer and cause an explosion. If the temperature is too low, the coal can not dry properly and difficult refined. The temperature should ideally approximately 650C.
Pulverizer equipped with Feeder (coal filler tool) that is located above the Pulverizer, serves to supply a number of coal in accordance with needs. These feeders have a container supply from coal coal called Silo (Coal Bunker).
c. Ignitor
The heat needed for combustion is provided by the ignitor. Once combustion begins, the burning fuel will supply enough heat to ignite the new fuel entering the boiler and the ignitor can be turned off.
6. Turbine
Energy conversion occurs in Turbine Blades, Turbine Blades have moved intermittently alternating arrangement with fixed Blade. Steam turbines will go into and fed directly into the Turbine Blades, Blades move and work to change the thermal energy in steam into rotational mechanical energy, causing the turbine rotor rotates, the rotation of this rotor will play Generator and finally mechanical energy into electrical energy.
Relationships equipment as well as the working principle of the turbine shown in the picture. Part - part of the turbine:
a. Nozzles
Serves to change the energy (nozzle) of potential to kinetic energy of steam.
b. Blades
Serves to alter a power play sped power.
c. Disck (turbine wheel)
Serves to continue the effort to turn the turbine-driven aircraft. Energy produced is mechanical steam power.
So the working principle of steam turbine is the potential energy is converted into kinetic tanaga on the nozzle and the kinetic energy is converted into rotary power at the Blade, with over Disck rotary power is converted into mechanical energy to the shaft.
7. Condenser
Having played the LP turbine steam then steam will flow into the Condenser to be cooled and turned into water. Condenser there are two A and B that is located under the LP Turbine A and B. The process that occurs in direct contact with the steam pipe in which a coolant flowing sea water. This change of steam condensing into water which is then stored in Condensaate Hot Well. Sea water in addition to functioning as a medium for heat transfer also serves to cool the condenser also cools the Closed Cooling System (water cooling). Closed Cooling System cools the various tools that require refrigeration such as Air Compressor, Pump and Generator Stator Cooling and is also important to cool the turbine oil for lubrication. The process of heat exchange between Close Cooling with sea water occurs in a device called the Heat Exchanger.
Because of the blow down on Steam Drum, then to restore the volume of water to its original volume, there is at Condenser Water Make-Up to increase the volume of water. Make Up Make Up water taken from Demineralizing RO. Condenser working in a vacuum, this is due to condensation processes occurred, ie the change of steam into water cause a reduction in volume. To keep the condenser in a vacuum, the gases released from the steam (when steam is turned into water) is pumped out by vacuum pump. Another reason is the efficiency of the vacuum, steam turbine is taken from Steam enthalpy (the excess steam in and out) so that the pressure is minimized for the greater use of energy because Enthalpi too big.
8. Polisher
From Hot Condensate Well, condensate water will be pumped by a condensate pump to the polisher. Condesate pump there are three, two active and one stand-by with a capacity of each pump is 50%. In polisher there reksin cations and anions, the resin serves as:
1. Cation resin: binding of negative ions causes corrosion.
2. Anion resin: binding of positive ions causes the crust or scale.
Tersebuit ions bound by the resin in the polisher to purify the water entering the boiler. Parameter of the ions can be measured by looking at its value conductyvity (normally 0.2). If the value of high conductivity, can mean two things:
1. There is a sea water leak in the polisher, detected with Leak Detector.
2. Resin has been saturated and must be regenerated. Regeneration of resin can be used:
- Resin Cation: using a strong acid (H2SO4)
- Resin anions: using base (NaOH)
From polisher, water is heated in the feed water heater 2,3 and 4 with the previously injected ammonia to increase pH (ideal pH = 9 - 9.5) for sodium than water is lost because sodium will cause material damage to the boiler. After that, new to the Feed Water Heater 5 in Daerator.
9. DAERATOR
Serves to absorb or eliminate the gas - gas that is contained in boiler water filler, especially the O2 gas, because the gas will corrode. Gas - a gas that was quite berbahya is carbon dioxide (CO2). O2 and CO2 gas will react with the material Boilers and corrode the very harmful.
The principle works of water which still contains O2 and CO2 is sprayed into the Steam Daerator, so that the gases are absorbed and excreted through the thermal release valve air / gas. Also Daerator also can raise the temperature of boiler water filler (up to 162 0C). Placement Daerator position that allows the provision of suction heat high enough for Feed Water Pump. From Daerator water will be pumped with three feed water pump, two pumps that power from the IP turbine extraction called Turbine Driven Pump and a motor-driven pump called the Motor Driven Pump, where the capacity of each pump 100% to the Feed Water Heater 6, 7, 8 AB and will go to the economizer continue to Steam Drum.
10. GENERATOR
Generator is a tool to generate electricity, the generator itself consists of stator and rotor. Associated with the turbine rotor shaft so that the spin-same together. Stator bars in a generator to bring the flow of power output relationship. Flow Direct Current (DC) Gear Brush which flowed through direct contact with slip rings mounted together with the rotor so that there will be a magnetic field (flux). If the rotor rotates, it cuts the magnetic field in the stator coils so that the ends of the stator coil voltage arises. For the supply of electric current generator was taken from outside the DC current. After a moment arises voltage generator, so that through exitasi AC current transformers will be rectified by the rectifier and DC current will return to the Generator, this process is called Self Excitation. In power systems, in addition to generators to supply electricity to a network of 500 KV extra high, also used for own use where the generator output voltage is derived through the transformers as needed. For the needs of the start to be taken from 150 KV line. For extra high voltage system electric power generated by the Power Plant suply to a network of 500 KV and further reduced by some voltage transformers as needed.
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