MAJOR TRAINING REPORT

MAJOR TRAINING REPORT201315/06/2013

A REPORT ON NTPC- VINDHYACHAL SUPER THERMAL POWER STATION C. &I. M.D.

TRAINING DONE BY:-AVNISH SINGH BAGHELJIWAJI UNIVERSITY, GWALIORMADHYAPRADESH

DURATION:-01/05/2013 TO 15/06/2013

Acknowledgement

At the outset I would like to convey my regards towards training department of NTPC, Vindhyachal for giving me such a great opportunity to observe and learn operation of this Super thermal Plant. My heartfelt thanks goes to Mr. ANIL SHRIVASTAVA, DGM (EMD), NTPC VINDHYACHAL who led the entire team of VSTPS for proper functioning of each department in a modernized and techno-commercial atmosphere to make the project touch such peaking performance. I also express my gratitude towards Mr. S.D.P. PANDEY (Senior Engineer, FES), without his assistance I would not be here. He has provided me the best moral support which I was in need for. I would give my special thanks to Mr. SANJAY SHARMA (HR-EDC), for giving his very kind permission to undergo the training programme under the able guidance of NTPC engineers. I would like to appreciate Mr Pankaj Kumar (Sr. Engineer., EMD DEPT), Mr .Vikas Gupta (Engineer, EMD.) & Mr. Ajit Singh( Engineer, EMD) under whose able guidance I completed the training. All these people were of immense importance regarding the knowledge and supports for the well furnished equipments. At last I would like to convey my appreciation to all the members of the Control & Instrumentation Dept. and members of various stages whose valuable guidance and suggestions helped me accomplishing this report.

ABOUT COMPANY

NTPC (National thermal power corporation) is Indias largest power generation company. It was set up in the year 1975 to accelerate power development in India. It has an installed capacity of 37,104 MW and planned to grow up to 75000 MW till year 2017.There are 15 coals based and 7 gas based plant in India located across the country. NTPC is the sixth largest thermal power generator in the world and the second most efficient utility in terms of capacity utilization based on data of 1998.

Dr. Arup Roy Choudhury,Chairman & Managing Director, NTPC Limited since September 01, 2010 and Chairman, DVC Since 29.11.2013, has an illustrious career spanning over 34 years of outstanding contribution in the fields of engineering, general management, strategic management and business leadership.Dr. Choudhury believes in growth and excellence through proactive approach and his dictum is "Sankalp Shuddha Hi Siddha" i.e. if your intentions are pure, you are bound to succeed.Dr. Choudhury has a strong commitment for the well-being of the society at large. His sharp focus on corporate governance and environmentally sustainable growth has been demonstrated in concrete actions and substantial benefits.

NTPC- VSTPS (VINDHYACHAL SUPER THERMAL POWER STATION)

NTPC Vindhyachal, located in Singrauli / Sidhi district of Madhya Pradesh, is one of the biggest Thermal power plants if India. NTPC Vindhyachal, owned and operated by NTPC Limited is located on the North West bank of Rihand Reservoir (Govind Ballabh Pant Sagar) at Vindhyanagar in Singrauli district of Madhya Pradesh. NTPC Vindhyachal Super Thermal Power Project is currently generating 3760 MW (210 x 6 + 500 x 2 + 500 x 2 + 500) and will be adding up 1000 MW in the next few years and will qualify as a one of the biggest power projects in India. It has currently one of the biggest switch yards in ASIA. It could be compared with the Ultra Mega Power Projects built by Reliance, Essar and Adani. Renukoot Station is about 50 Km away from project site while Shaktinagar station is 10 Km away. Varanasi is the nearest major town 220 Km away connected by Road and railway link.

The 210 MW units were built initially with the help of Russian support. Thereafter the 500 MW units were built up with the help of M/s BHEL. The initial years of commissioning of 210 MW units were a learning phase for Indians and M/s BHEL, thereafter the experience helped in the further expansion of power projects indigenously. Stage 2 comprising of 800 MW x 2 was supposed to be built up with the help of Russian support, but the disintegration of USSR in the 1990's did not help the cause, thereafter the plan was scrapped and it was built up as 500 MW x 2 with the help of BHEL.

VSTPS is accredited with ISO 9001, ISO 14001 and OHSAS 18001. The 210 MW units were made with Russian support. A lot of renovation and Maintenance has taken place since then. ABB made Symphony Harmony DCS is installed there. The 500 MW units are BHEL made units of which 7 and 8 had ABB made Procontrol p13 DCs and Unit 9 and 10 are having Max DNA DCS by BHEL.

UNIT NOCAPACITYCOMMISIONED ON

STAGE-1UNIT-1UNIT-2UNIT-3UNIT-4UNIT-5UNIT-6

STAGE-2UNIT-7UNIT-8

STAGE-3UNIT-9UNIT-10

STAGE-4UNIT-11UNIT-12

210MW210MW210MW210MW210MW210MW

500MW500MW

500MW500MW

500MW500MW

OCTOBER 1987JULY 1988FEBRUARY 1989DECEMBER 1989MARCH 1990FEBRUARY 1991

MARCH 1999FEBRUARY 2000

JULY 2006MARCH 2007

MARCH 20132014

TOTAL 4260MW

** STAGE- 5 IS UNDER CONSTRUCTION.

PRODUCTION OF ELECTRICITY:

Coal to Electricity The means and steps involved in the production of electricity in a coal-fired power station are described below. The coal, brought to the station by train or other means, travels from the coal handling plant by conveyer belt to the coal bunkers, from where it is fed to the pulverizing mills which grinds it as fine as face powder. The finely powdered coal mixed with pre-heated air is then blown into the boiler by fan called Primary Air Fan, with additional amount of air called secondary air supplied by Forced Draft Fan. As the coal has been grounded so finely the resultant ash is also a fine powder. Some of this ash binds together to form lumps which fall into the ash pits at the bottom of the furnace. The water quenched ash from the bottom of the furnace is conveyed to pits for subsequent disposal or sale. Most of ash, still in fine particles form is carried out of the boiler to the precipitators as dust, where it is trapped by electrodes charged with high voltage electricity. The dust is th en conveyed by water to disposal areas or to bunkers for sale while the cleaned flue gases pass on through ID Fan to be discharged up the chimney. Meanwhile the heat released from the coal has been absorbed by the many kilometres of tubing which line the boiler walls. Inside the tubes is the boiler feed water which is transformed by the heat into the steam at high pressure and temperature. The steam super-heated in further tubes (Super Heater) passes to the turbine where it is discharged through the nozzles on the turbine blades. Just the energy of the wind turns the sail of the wind-mill, so the energy of the steam, striking the blades, makes the turbine rotate. Coupled to the end of the turbine is the rotor of the generator a large cylindrical magnet, so that when the turbine rotates the rotor turns with it. The rotor is housed inside the stator having heavy coils of copper bars in which electricity is produced through the movement of the magnetic field created by the rotor. The electricity passes from the stator winding to the step-up transformer which increases its voltage so that it can be transmitted efficiently over the power lines of the grid. The steam which has given up its heat energy is changed back into water in the condenser so that it is ready for re-use. The condenser contains many kilometres of tubing through which the colder is constantly pumped. The steam passing around the tubes looses the heat and is rapidly changed back to water. But the two lots of water (i.e. boiler feed water & cooling water) must never mix. The cooling water is drawn from the river, but the boiler feed water must be absolutely pure, so as not to damage the boiler tubes. Chemistry at the power station is largely the chemistry of water. To condense the large quantities of steam, huge and continuous volume of cooling water is essential. In most of the power stations the same water is to be used over and over again. So the heat which the water extracts from the steam in the condenser is removed by pumping the water out to the cooling towers and then the cooled water is recirculated again through the condenser.

Steps Involved In Power Generation In VSTPS The conversion of coal into electricity consists of various intermediate stages. This are described below 1. Coal handling Plant:- CHP is the first stage of any Thermal Power Plant .The coal from the mines is brought to the plant by use of Coal wagons. . Merry-Go-Round rail system of transport is adopted for transportation of coal from the mines to plant site. NTPC has its own MGR system which results in an annual profit of 45 crores. Coals are unloaded by track hoppers. As the coal from mines contain particles of different sizes, so water is sprinkled on the coal so as to stop flow of coal with air and to stop the loss. Coal in the track hopper is then send to crusher house for crushing it to size no less than 20mm. Crushed coal is sent to bunkers through conveyer belt system. Afterwards according to requirement coals are taken into mills through gravimetric feeder to pulverize it to a size of 200 meshes. Primary air mixed with pulverized coal is fed to the centre of boiler burning zone. Pre heated secondary air enters boiler, surrounds the pulverized coal and helps in combustion.

2.Air Draft System:Primary air system: Ambient air is drawn into the primary air ducting by two 50% duty, motor driven axial reaction fans. Air discharging from each fan is divided into two parts, one passes first through a air pre-heater then through a gate into the P.A bus duct. The second goes to the cold air duct. The mix of both is used to carry the pulverized coal to the boiler.

Secondary air system: Ambient air is drawn into the secondary air system by two 50% duty, motor driven axial reaction forced draft fans with variable pitch control. Air discharging from each fan passes first through a air pre heater then through a isolating damper into the secondary air bust duct. The cross over duct extends around to each side of the boiler furnace to form two secondary air to burner ducts. At the sides of the furnace, the ducts split to supply air to two corners. Then split again to supply air to each of nineteen burner/air nozzle elevations in the burner box.

Primary and Secondary air System in the Boiler:

Air Preheater: Air preheater is heat transfer surface where temperature of air is raised by flue gas. It gives: -Improved boiler efficiency- Improved combustion- Hot primary air for drying coal

Induced draft system: It sucks flue gas from boiler and releases it to atmosphere through chimney. The flue gas contains fly ash particles, deposited in ESP hoppers and SOx, NOx etc. The flue gas path is shown below

Electrostatic Precipitator (ESP): It is a device which captures the dust particles from the flue gas thereby reducing the chimney emission. Precipitators function by electrostatically charging the dust particles in the gas stream. The charged particles are then attracted to and deposited on plates or other collection devices. When enough dust has accumulated, the collectors are shaken to dislodge the dust, causing it to fall with the force of gravity to hoppers below. The dust is then removed by a conveyor system for disposal or recycling.

Theory of Precipitation: Here six activities typically takes place. Ionization - Charging of particles. Migration - Transporting the charged particles to the collecting surfaces. Collection - Precipitation of the charged particles onto the collecting surfaces. Charge Dissipation - Neutralizing the charged particles on the collecting surfaces. Particle Dislodging - Removing the particles from the collecting surface to the hopper by rapping mechanism. Particle Removal - Conveying the particles from the hopper to a disposal point governed by fly ash disposal system.Major Fans in Boiler Draft System: PA Fans FD Fans ID Fans

PRIMARY AIR FAN: It serves two main purposes:a) Transportation of coal from mill to furnaceb) Coal moisture removal NO OF FANS PER BOILER : TWO TYPE : RADIAL INDUCTION MOTOR RATING : 1480 KW SPEED : 1480 RPM CONTROL: INLET VANE CONTROLFORCED DRAFT FAN: It provides air for combustion. NO : TWO TYPE : AXIAL REACTION MOTOR RATING : 800 KW SPEED :1480 RPM CONTROL: BLADE PITCH CONTROL

INDUCED DRAFT FAN: It maintains furnace draft. NO OF FANS PER BOILER : TWO TYPE : AXIAL IMPULSE MOTOR RATING : 1300 KW SPEED : 740 RPM CONTROL: INLET VANE CONTROL

Steam cycle:- The demineralised water, which is used to produce steam, passes through various intermediate stages. The DM water passes through a series of water heaters namely LP heaters, Gland Steam Cooler(GSC),HP heaters and afterwards passes through Deaerator, Boiler feed pump, economizer and then goes to boiler drum. In LP heater and HP heater ,heat is transferred from steam (coming from turbine) to water which increases the temperature of the water. The direct mixing of steam with water is not allowed. In Deaerator, steam comes in direct contact of water. Deaerator is used to remove the air of feed water to prevent corrosion of boiler tubes and turbine blades. The presence of air also reduces the efficiency of cycle. The boiler feed pump is used to pump water to boiler drum through economizer. Boiler Economizer are feed-water heaters in which the heat from waste gases is recovered to raise the temperature of feed-water supplied to the boiler. In the midst of HPH and Economizer, a three element feed flow regulating system has been incorporated which regulates the steam flow from the boiler, the feed water flow to the boiler and the water level in the boiler drum.The boiler drum serves two purposes:-1. Separating steam from mixture of water and steam 2. It houses all the equipments for purification of steam. In VSTPS the boiler used is water tube boiler. Here the heat source is outside the tubes and the water to be heated is inside. Most high-pressure and large boilers are of this type. In the water-tube boiler, gases flow over water-filled tubes. These water-filled tubes are in turn connected to boiler drums. In stage I natural circulation takes place. Natural circulation is the ability of water to circulate continuously, with gravity and changes in temperature being the only driving force known as "thermal head.

The down comer contain relatively cold water, whereas the riser tube contain steam water mixture ,whose density is comparatively less .this density difference is the driving force ,for the mixture. (thermo-siphon principle).Circulation takes place at such a high rate that the driving force and frictional resistance in water wall are balanced. Natural circulation is limited to boiler with drum operating pressure around 175 Kg/cm2.However, when the pressure in the water-tube boiler is increased, the difference between the densities of the water and saturated steam falls, consequently less circulation occurs. To keep the same level of steam output at higher design pressures, the distance between the Bottom ring header and the steam drum must be increased, or some means of forced circulation must be introduced. Beyond 180 Kg/cm2 of pressure, circulation is to be assisted with mechanical pumps, to overcome frictional losses. This is known as forced circulation which is employed in stage II and stage III. The water coming from boiler drum on its passage through down comer and riser tube is converted into a mixture of water and steam and goes back to boiler drum. The steam from boiler drum passes through a series of super heaters like LTSH (Low temperature Super Heater), Platen super heater, convective super heater. Super heater heats the high-pressure steam from its saturation temperature to a higher specified temperature. The steam at super heater outlet gains a temperature of 5400C. It is then passed to HPT (High Pressure turbine) and the temperature of the steam goes down. The steam is sent back to reheater to gain back the temperature. The reheated steam is sent to IPT (Intermediate Pressure Turbine), then from IPT to LPT(Low pressure turbine). The HP, IP, LP turbines and the rotor of the turbo generator are connected on the same shaft. As the high pressurized steam drives the turbine blades, so rotor of the generator also rotates. The steam after losing its pressure begins to condense in condenser by exchanging heat with circulating cooling water. The condensate is then move to hot well. Then from hot well the condensate is pumped by CEP (condensate extraction pump) to LP heater. The cycle continues which is termed as steam cycle.Steam Turbine: The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency from the use of multiple stages in the expansion of the steam. High pressure steam flows through the turbine blades and turns the turbine shaft. Steam turbines extract heat from steam and convert it into mechanical work by expanding the steam from high pressure to low pressure. Steam turbine shaft is connected to a synchronous generator for producing electricity.Circulating Water System: Bulk requirement of water is used in thermal plants for the purpose of cooling the steam in condensers. The requirement of water for this purpose is of the order of 1.5-to2.0 cusecs/MW of installation. In VSTPS closed loop cooling system with cooling towers is used for this purpose. The heat which the water extracts from the steam in the condenser is removed by pumping the water out to the cooling towers. The cooling towers are simply concrete shells acting as huge chimneys creating a draught (natural/mechanically assisted by fans) of air. The water is sprayed out at the top of towers and as it falls into the pond beneath it is cooled by the upward draught of air. The cold water in the pond is then circulated by pumps to the condensers. Inevitably, however, some of the water is drawn upwards as vapours by the draught and it is this which forms the familiar white clouds which emerge from the towers seen sometimes. Water Treatment plant: Different water qualities are in use in VSTPS. For condenser cooling, ash handling plant and other auxiliaries cooling raw water (clarified and post-chlorinated) is used. Again conditioned Demineralised water is used for boiler feed water and H2 generation plant. For drinking purpose also filtered & post-chlorinated water is provided. a) Cooling water Management: In the pre-treatment process, chemicals are added in raw water for bacteria removal and for sedimentation of suspended particles. Then it is pumped through clariflocculators. The clarified water from these clariflocculators flows to the cooling water basin by gravity. A clarified pump is present which pumps the clarified water to the DM plant. The outlets from the cooling water tower basins are connected to the common tunnel which takes the water back to the power house. From this tunnel water is drawn through the following pumps to the various equipments as follows:

1) CW Pumps for circulating cooling water through turbine, condenser and discharging the same to the op of the respective cooling towers.2) Auxiliary Cooling Water Pumps for supplying cooling water to various auxiliary equipment for their cooling . This water after circulation through various bearings and heat exchangers leads to the CW discharge pipe from the condenser for cooling through the cooling tower.3) Ash water pumps for supplying water for ash handling.

b) Demineralised water Plant: A demineralising plant is provided for supplying feed water for the heat cycle. . Clarified water is pumped from the clarified water storage pit which passes through pressure filter, activated carbon filter, cation-exchanger, degasser, anion-exchanger and mixed bed exchanger. Adequate facilities are provided for unloading, handling and storage of chemicals. The layout of operation is shown below.

ACF: Activated Carbon FilterWAC: Weak Acid CationSAC: Strong Acid CationWBA: Weak Base AnionSBA: Strong Base AnionMB: Mixed BedCST: Condensate Storage Tank

Hydrogen Generation Plant: This process involves electrolysis of water in an electrochemical cell. The electrolyte used is KOH (30%)+H2O in presence of K2Cr2O7 (1%)catalyst. The water used is D.M. water with temperature kept very low. 60 volts D.C. supply is applied to the electrolyte solution. Gas production is directly proportional to Direct Current passing through the solution of caustic potash and D.M. water. The hydrogen generated is processed in the following way.

Hydrogen Bottling Plant: In hydrogen bottling plant the bottle pressure is maintained at 135 kg/cm2. 3 compressors are used to create the required pressure. Bottled H2 is 99.9% pure.Ash Handling Plant: Ash is the residue remaining after the coal has been incinerated to constant weight under standard conditions. It is oxidized form of the mineral matters present in coal.Typical ash composition: SiO2, Al2O3, Fe2O3, CaO, MgO etc. Ash content of Indian coal used in power station is about 30 to 40 %. A typical 2000 MW station produces around 9000T to 12000T of ash per day. This huge amount of ash needs to be disposed off continuously for avoiding pollution.

(a) Bottom Ash: 20 % Of the ash falls at the bottom of the furnace known as Bottom Ash (BA). BA can form slag and clinker depending on the temperature of the combustion zone and environment inside. Bottom ash is disposed of through bottom ash disposal system.

Bottom ash handling system: Bottom ash can be collected at furnace bottom as Wet or Dry form. Wet bottom ash system consists of i)Trough seal, ii)BA gate, iii)Hopper, iv)Scrapper Conveyer, v)Clinker grinder,vi)BA trench, vii)BA tank, viii)BA pump, ix)BA pond.

Dry bottom ash system consists of i)Trough seal, ii)BA gate, iii)Hopper, iv)Scrapper Conveyer, v)Clinker grinder, vi)Silo.

(b) Fly Ash: 80 % of the ash is carried away with flue gas known as Fly Ash. Fly ash is collected through ESP and disposed through fly ash disposal system.

Fly ash handling system: Fly ash is collected from Air heater hopper, Economiser hopper and ESP hopper either through flushing apparatus or hydrobacter system. In Flushing apparatus system ash is allowed to fall in flushing apparatus under gravitation. Water jet in flushing apparatus carries away the ash to FA trench. High pressure jets further carries it to FA sump. Series pumping carries the ash slurry to FA pond. Hydrobacter is a vacuum device to collect ash from the hopper. Water jet ejectors are used for creating vacuum. Dry ash thus collected is sent to silo through belt conveyor. Dry ash is disposed through road transport to a dry ash disposal system. Part of it is sold for commercial purpose.

Ash Utilization:Major usages of ash are: Fly ash bricks / blocks Concrete and mortar In manufacture of cement In manufacture of asbestos products Road construction Embankment/back fills/land development In agriculture Mine filling Manufacture of fertilizer Manufacture of distemper Floor and wall tiles Refractory bricks Manufacture of ceramics Manufacture of alum Domestic cleaning powder In synthetic wood

Fuel oil System:

The purpose of fuel oil is:1) To establish initial boiler light up.2) To support the furnace flame during low load operation. Fuel oil system consists of fuel oil pumps, oil heaters, filters and steam tracing lines. The objective is to get filtered oil at correct pressure and temperature.Types of fuel oil:a) Light diesel oil (LDO)b) High speed diesel oil (HSD)c) Heavy furnace oil (HFO)d) Low sulphur heavy stock (LSHS) Atomization procedure is used to break the fuel into fine particles that readily mixes with the air for combustion.Seal and Lube Oil system: Seals are employed to prevent leakage of hydrogen from the stator at the point of rotor exit. A continuous film between the rotor collar and the seal liner is maintained by means of oil at a pressure which is about 0.5 atmosphere above the casing hydrogen gas pressure. The thrust pad is held against the collar of rotor by means of thrust oil pressure, which is regulated in relation to the hydrogen pressure and provide a positive maintenance of the oil film thickness.Lube oil system is provided for bearings upon which the generator shaft is mounted.

SPECIFICATION OF MECHANICAL SYSTEMS:Steam Generator:The steam generator is a natural circulation pulverized coal fired, radiant furnace, dry bottom, balanced draft type using direct firing system.The parameters of the steam generator at 100% MCR will be as follows:For stage I (6210 MW):1) Maximum continuous rating 670 T/hr2) Superheater outlet temperature 5400C3) Superheater outlet pressure 140 kg/cm24) Cold reheat pressure at boiler inlet 27.5-27.9 kg/cm25) Hot reheat outlet temperature 5400C6) Reheat steam flow 590 T/hr7) Feed water temperature at Economiser 2480C InletFor stage II and stage III (each 2500 MW):1) Main steam flow at superheater outlet 1590 T/hr2) Pressure at superheater outlet 179 kg/cm23) Temperature at SH outlet 5400C4) RH steam flow 1353 T/hr5) Steam temperature at reheater outlet 5680C6) Feed water temperature at Economiser 255+-50C Inlet The steam generator is a natural circulation pulverized coal fired, radiant furnace, dry bottom, balanced draft type using direct firing system. The boiler furnace is with a steam drum. The drum supplies water wall system through adequate sized six (6) down comers so as to permit unrestricted circulation. Each steam generators equipped with three (two working and one standby) of axial type ID fans and two, of centrifuge type FD fans. Six PA fans on the hot air side of air heaters is provided to supply hot air to the mills. There is two regenerative rotary air heaters. There are electrostatic precipitators having an efficiency of 99.5% for collecting fly ash. Each steam generator is provided with six medium speed of direct firing type with provision of one standby. Main steam from the boiler is supplied to HP turbine (HPT) through two pipes. Cold reheat (HPT exhaust) will be returned to the boiler reheater through two numbers of pipes. Hot reheat steam from boiler will be supplied to IP turbine through four pipes. The turbine is provided with an automatic governing system and protection devices which ensure turbine operation and tripping under emergency conditions. The governing control system includes speed governor, emergency governor, speed changer, load limiting device, and initial pressure regulator. Coal for the thermal power station is transported from Nigahi open cast mines. Merry-Go-Round rail system of transport is adopted for transportation of coal from the mines to plant site.There is an ash handling system of continuous hydro sluicing type.There is a bottom ash handling system to extract and handle bottom ash. The fly ash system employs flushing equipments to remove the ash from electrostatic precipitator hoppers and gas ducts low points after regenerative air heater on continuous basis. From the main pump the ash slurry is continuously transported to the disposal area by means of ash slurry pumps and disposal pipes. For the circulating water scheme a closed circuit cooling system using cooling towers is used. Six numbers induced draft type cooling towers is provided for stage I of the power plant. The C.W. system has C.W. pumps, travelling water screen, butterfly valve and actuator and cooling towers.There is a water treatment plant which meets up the following requirements. (i) DM water for boiler make up(ii) Portable water for colony and plant(iii) Clarified water for CW system and auxiliary cooling make up along with other requirements such as coal dust suppression, water services, ash handling etc. Removal of suspended colloidal matter in the raw water is removed in the pre-treatment plant. The chemical dosing system is there for unloading, handling, solution preparation and dosing of alum, lime and coagulant aid solution. The demineralising plant consists of four streams of 110 m3/hr capacity each comprises of active carbon filter, weak and strong acidic cation exchanger, degasser system and weak and strong base anion exchangers followed by mixed bed polishing unit. For fire protection H.P.W. spray system is provided to generating transformer, station transformer, tie transformer, unit aux. transformer, turbine oil storage tanks, oil cooler and seal oil system. The hydrogen generating plant is provided with two electrolysers, each of nominal capacity of 10 m3/hr for meeting the makeup requirements of the plant. Very high purity for hydrogen (99.9%) is achieved by the electrolysis process.