Model 9224 | coal Feeder | CONSTRUCTION

The feeder is comprised of feeder frame, feeder belt assembly, cleanout conveyor, weighing system, coal
plug-gage and coal void signaling devices. lubrication piping and electric wiring, microprocessor control cabinet.
• The feeder frame is comprised of casing, inlet and discharge end doors, side doors and internal feeder light. The casing is an enclosed weldment that can resist explosive pressure up to 0.34 MPa to meet requirements specified in NFPA Code 85F by National Fire Protection Association of the U.S.A. Guide plate and skirt are provided in the inlet to form fixed section of coal flow on the belt after coal is dropped into the feeder. All parts contacting coal are made of OCr18Ni9Ti stainless steel. Inlet and discharge end doors are firmly bolted to the casing to ensure perfect seal. All doors are optional to open leftward or rightward. sight glasses are provided on all doors and nozzles are equipped interior of sight glasses to clear off accumulated coal dust by pressurized air or water. Internal feeder light of sealed construction enables observation of internal feeder operation.


• The feeder belt assembly is comprised of motor, reducer, drive pulley, take-up pulley, tension roll, belt supporting plate and the belt. The belt is rimmed and provided with a v-guide at the inner belt center to engage with grooves on rollers to keep good belt tracking. At the end of drive pulley scraper is equipped to clear off coal adhered on the outer surface of belt. The tension roll is located at the midpoint of bell travel, it keeps the belt under a fixed tension to obtain optimum weighing effect. The belt tension varies with different temperature and with temperature variation. Intensive observations should be frequently done and make tension adjustment by means of the take-up screws. Scaled indicator is equipped interior of side door to the feeder, the tension roll should be regulated to locate its center at the midpoint of the indicator. Totally enclosed, variable frequency motor is used to drive the belt. Which is comprised of a 3-phase ac motor, a tacho-generator. A variable frequency driver and variable frequency motor provide an ac stepless speed regulation .It can provide a smooth and stepless speed regulation within a rather broad range. The feeder belt reducer is a two-stage reducer, comprised of cylindrical gears and worm wheel. The worm wheel is oil bath lubricated while a cycloidal pump in the reducer pumps oil via a hole in the worm shaft to 3 lubricate the gears. The drive pulley is driven through a pin type coupling which is mounted on the worm wheel shaft.
• The coal void signaling device is located above the belt. When there is no coal on the belt, the paddle of signaling device deflects and causes cam on the axle of device to turn and actuate the limit switch, either to control the belt drive motor, or to initiate the coal bunker vibrator, or to output a signal back to control room to signify no coal on the belt. The customer may determine, according to operating system requirements, which of these functions shall be performed. The coal void signal can also deactivate integrated weight and can prevent feeder calibration with coal on the belt. The coal plug-gage signaling device locates at the feeder discharge and is of identical construction to the coal void signaling device. The limit switch outputs signal signifying coal flow plug-gage at discharge and stops the feeder operation.
• The weighing system is located between feeder inlet and drive pulley. All of the three roller surfaces are finely finished, of which two rollers are fixed on the feeder casing to form a weigh span and the third roller hangs on a pair of load cells. Coal weight on the belt acts on load cells to output a signal. Output signal from the calibrated load cells signifies unit length coal weight and frequency signal from the tacho-generator signifies belt speed. The microprocessor controls integrates both signals to obtain the feedrate. Test weights are located below the load cells and the weigh roller. During feeder operation, test weights are supported by the weigh arm and the eccentric disc to part from the weigh roller. On calibration, turn the ratchet handle so that the eccentric disc is turned to make test weights hang on the load cells to check if the weight signal is correct.
• Cleanout conveyor is used to clean off coal accumulated on inner floor of the feeder. During feeder operation, coal adhered on the belt is cleaned off by a scraper and dirt accumulated on inner belt is dropped off from both ends of the self-cleansing type tension roll. As seat air also generates dirt, dirt will deposit on the inner floor to cause self-ignition if it is not timely cleaned off. Cleanout chain is driven by a motor via a reducer, wing type chain scrapes off the dirt to the feeder discharge. It is recommended that the cleanout conveyor is synchronously operated with the feed bell operation so that coal accumulation interior of the feeder is minimized. Furthermore, continue clean off is also of advantage both to reduce feedrate error and to prevent chain pin from adhesion and rustiness. The cleanout conveyor reducer is comprised of cylindrical gears and worm wheel. Electric overload protection is provided for the cleanout conveyor drive motor, when overload the cleanout conveyor motor’s power is automatically turn off by electronic overload relay to stop reducer.
• Seal air inlet is located below the feeder inlet with a flange-type connection for the customer to supply seal air into the feeder. Under pressure operation status, the feeder needs sear air to prevent pulverizer heat air from reversing into the feeder through the inlet. The seal air pressure is 60～245 Pa higher than the pulverizer inlet pressure. The required seal air delivery is the sum of air leakage from hopper of downspout and the amount required to form a pressure difference between inlets of the feeder and of the pulverizer. The feeder itself is construed as of reliable sealed with no leak. A threaded hole is provided near the feeder inlet for adapting a pressure gauge to test the feeder internal pressure. The hole must be plugged if a pressure gauge is not equipped. If the seal air pressure is too low, it will cause the pulverizer heat air reverse back to the feeder so that coal dusts will stagnate at the door frames and at protrusion parts to induce self-ignition. If either the seal air pressure or its flow rate is too high, it will blow coal particles off the belt to degrade weighing accuracy and to increase the load on clean out scrapers. 4 Furthermore, if the seal air flow rate is too large, dustiness is prone to be formed interior of the sight glass to hamper observation. Therefore, suitable seal air pressure has to be adjusted.
• Except that the reducer is oil bath lubricated, grease lubrication is used for all other parts. All lubricating points within the feeder are connected with hoses that extend outside the feeder so that, lubrication can be performed without opening doors to the feeder. Flexible tubes are used for electric wiring, cables are led into the feeder through the tubes so that casing seal is kept.
• Control cabinet is installed on the body of the feeder. Power supply switch is located in cabinet. It can turn on or turn off the power.
• Microprocessor control board, power supply board signal converting board, variable frequency driver disconnect switch, transformers, fuses and relays are installed within the microprocessor control cabinet which is mounted on the feeder casing. On the panel of cabinet microprocessor display keyboard and switches SSC and FLS are equipped. For their functions.

Related articles

• Electric Power Production Process (human-style.blogspot.com)
• On Coal River (MOVIE) (planetsave.com)

»»  NEXS...

Displacement | Gear | Pumps | Series D/H/HD

Performance Data
Series D Fixed Displacement, Pressure-Loaded Gear Pump
Features
• Pressure-loaded design
• Efficient, simple design - few moving parts
• Exceptionally compact and lightweight for
their capacity
• Efficient at high pressure operation
• Resistant to cavitation effects
• High tolerance to system contamination
• Reliable under cold weather operation
• Sleeve-bearing construction
• Multi-fluid compatibility
Controls
• Optional built-in relief valve
• Consult factory for special controls
Specifications
Flow Ratings:
.5 GPM (1.9 LPM) to 2.7 GPM (10.2 LPM)
(At 1000 RPM) See next page for additional
flow data.
Pressure Ratings:
D05 thru D22 - 2500 PSI (172 Bar) continuous
D27 - 2000 PSI (138 Bar) continuous
Speed Ratings:
D05 thru D22 - 500 to 4000 RPM
D27 - 3000 RPM
Mounting:
SAE-AA - 2-Bolt Flange
4-Bolt Flange
Housing Material:
Die-Cast Aluminum

Installation Data
Inlet Conditions:
10 in. hg. max. vacuum condition
(At 1800 RPM)
5 in. hg. max. vacuum condition
(At max. RPM)
20 PSI (1.4 Bar) max. positive pressure
Operating Temperature Range:
-40°F to 185°F
(-40°C to 85°C)
Filtration:
Maintain SAE Class 4

A Parker pressure-loaded gear pump consists of two, intermeshing, hardened-steel, precision-ground gear assemblies. These precision gears are enclosed by a high-strength, die-cast aluminum front cover, back cover and a high-yield, strength-extruded aluminum
center section.

Gear assemblies consist of one drive gear, shrinkfitted on a precision-ground and polished drive
shaft. This shaft extends outside the pump to permit coupling to an external prime mover. The second
gear, being the driven gear, is also shrink-fitted on a precision-ground and polished driven shaft. Retaining rings, which are installed in grooves provided on the shaft, ensure that the gears will not move axially, and a key keeps the drive gear from moving radially. A lip-type, shaft seal is provided at the drive shaft to prevent external leakage of pump fluid. The sealing lip in contact with the fluid is spring-loaded. Vent passages within the housings and driven shaft communicate pump inlet pressure to the rotary seal area, thus imposing the lowest possible pressure at the rotary seal for extended seal life.

The phenolic heat shield, backup gasket, and molded rubber seal form chambers behind the steel-backed bronze wearplate. These chambers are connected either to inlet or discharge pressure. Discharge pressure, acting within the chambers, axially loads and deflects the wear plate toward the gear faces to take up gear side clearances. This pressure-loading on the wear plate increases pump efficiency by reducing internal leakage to a minimum, providing longer pump life. Pump rotation is dependent upon the proper orientation of the heat shield, backup gasket, and rubber seal in the front cover housing, the center section and rear cover, respectively. Pumping action is achieved by connecting the pump drive shaft to a prime mover, and rotating the gears away from the inlet port. Rotation causes the gear mesh to increase on the inlet side and decrease on the outlet (pressure) side.

»»  NEXS...

Steam | Turbine | Of Plants

Type Steam Turbine
- Based on the energy transformation process:
- Turbine impulse
- Turbine reaction
- Under pressure steam turbine
- Back pressure
- Condensing.
- Under the pressure of steam into the turbine
- Super critical pressure (225 bar)
- Very high pressure (170 bar and above)
- High pressure (above 40 bar).
- Pressure medium (s / d 40 bar).
- Low pressure (1.2 - 2bar abs)
- Based on the steam setting in.
- Constant pressure with throttle control.
- Constant pressure with Nozzle control.
- Sliding pressure

a) The speed of the steam out nozzle Ct = 192.6 m / s, then the magnitude of thrust force P1 = m (C1t-C2) = 1/9, 81 (196.2-0) = 20kg.
b) P2 = 1/9, 81 (196.2 +196.2) = 40kg
c) P3 = 1/9, 81 (196.2 + cos300
196.2 cos300) = 34.7 kg.
Relative velocity steam strikes the blade because the blade moves C1t w1 =-U, and if U = 98.1 m / s the thrust
a) P1 '= 1/9, 81 (196.2 to 98.1) = 10kg
b) P2 '= 2/9, 81 (196.2 to 98.1) = 20kg
c) P3 '= 2/9, 81 (196.2 cos300 -
98.1 cos300) = 34.7 kg.

Start-up turbine is divided into 3 types:
Cold start-bin that is if the tour has stopped more than 120 hours. To start this kind requires the longest time: 360 minutes
Warm start when the turbine stopped between 24 -72 hours. Start-up time full load: 160 minutes
Start the heat if turbine stopped less than 6 hours. Start time to 30 minutes at full load
Make sure that the temperature and vapor pressure are in accordance with the type of start before the steam is inserted into the turbine.
Slowly open the throttle valve slowly and manually note langkah2 accretion rate and rotation relative to the current state adjusted in accordance with the user expansionnya
Rapidly through the critical rotation.
Do a test protective device when rotation reaches sinkroon round.
Do a test overspeed if the unit runs out overhaul
Immediately add the flow of steam after sinkroon.
Do a manual trip if the unit runs out overhaul.
Loading the next match with the user.

 internal losses are losses associated with making the steam in the turbine.
• Losses in the valve pe-
ngatur steam turbine entry ΔH
• Losses in the nozzle or
fixed blade hn
• Losses didlm blade path hb
• Losses due to increased steam
hl blade left behind
• Losses due to friction steam
with disc blade holder
• Losses in sealing an-
tar levels of blade (labirint).
• Losses caused by wet steam

 external losses are losses that are not related to the course of the steam in the turbine as mechanical losses and losses in the steam turbine shaft sealing.
Lubrication of turbine generator system it functions:
 Establish intermediate layer (with a certain thickness) so that no direct contact between the shaft and bearings, and dirt do not hurt the oil carried by the bearing surface.
 Throw away the heat arising from friction in the bearings or the other.
Condition so that the lubricant must be guaranteed not to damage the parts in its path, because it is equipped with a turbine lubrication system cleaning system known as the "oil condtioner"
Wet steam or vapor containing water will cause erosion on turbine blades, because the grain must be removed from the grains of water vapor passes through the extraction channel and especially in the last fixed blades pengkap given channel and waster water.

»»  NEXS...

Lubrication | for Industrial | Plants

Making Lubricants
Lubricating oil used in generating engines lubricant is mineral oil. Manufacture of mineral lubricating oils made ​​in oil mills by the fractionation of raw material (crude oil). Lubricating oil can also be made from a variety of basic materials such as:
- Lubricating oils made ​​from plants and from animals
such as castor oil (Castrol Oil), use as seed
the base material. Vaseline, using animal fat as an ingredient
basically.
- Synthetic lubricating oils. Derived from synthetic materials (eg Polyqlycols,
basic zdi Acid esters, Fluoroesters, Polyphenil esters, a Novel Synthetic, Lubricants, etc.)


Capabilities and advantages of this mineral include:
- Temperature operating range is quite large
- Easily mixed with chemicals to increase
- Ability to work
- Nature of Physical and Chemical Properties easily controlled
Material wear can be reduced by reducing the magnitude of the force due to friction is by avoiding the direct contact between two surfaces rub against each other. One way to avoid direct contact between two objects rub against each other is to "insert" the lubricating oil between the two objects. This method is called "lubricate" or provide lubrication.
Lubrication principles can be divided into two kinds:
• Boundary Lubrication.
Lubrication where the surfaces are the two objects rub against each separated by a very thin layer of lubricant so that in some locations is still friction between the two objects. See Fig.
• Lubrication Film.
By providing a layer of lubricating oil that is thicker (a film) between the two objects rub together, no longer the case friction between two objects. Principles of good lubrication is the lubrication film.
The main function of lubricating oil is for lubrication, while other functions are equally important for cooling, sealing, reduce corrosion, shock absorbers and control.
• As a coolant.
Friction will cause excessive heat can cause damage if material. Lubricating oil will absorb the heat is to be taken and disposed in the lubricating oil or cooling system to the outside air.
• As the seals.
Seals can be used as a lubricant, such as to prevent leakage of hydrogen from the alternator shaft to the outside air.
• To reduce corrosion.
Lubricants can reduce the rate of corrosion because it forms a protective layer on the metal surface so that direct contact between the substance causes corrosion of metal surfaces can be avoided or reduced.
• As shock absorbers.
Shock loads on engine components can occur, including the gears. Lubricant layer will lessen the impact between the gear surfaces intersect each other, so as to reduce vibration and noise.
Additives to improve the characteristics of lubricants, to suit their usage requirements. Additive: Chemicals that have received "Patent" from the factory.
 Detergent: to clean machinery
 Dispersant: to keep all the dirt floats / float in the lubricating oil
 Antioxdant: to prevent the process
 Anticorrosive: prevent kososi
 Antifrezing: to prevent freezing
 Increasing the viscosity index: to keep the lubricants remain fluid in cold temperatures
 Antifoam: to prevent foam
 Extreme Presure: to form a thin layer of strong, resistant to pressure
 antirust: to prevent the formation of rust due to the deviation of pressure

»»  NEXS...

Cycle of | Basic | Feed | Water | Heater

The main function of the Feed Water Heater is increasing efficiency in power plant steam cycle. Extraction steam from the turbine used to heat the feed water so that the Final Feed Water Temperature had passed (from point A to M). Feed Water Heater is basically a heat exchanger (heat exchanger). Power plant has 7 units of Feed Water Heater is 3 units of Low Pressure Heater (LPH 1, 2 and 3), 3 units of High Pressure Heater (HPH 5, 6 and 7) and the Open Feed Water Heater is Daerator. For LPH and HPH 5,6,7 1,2,3 is Close Feed Water Heater with shell and tube type heat exchanger.

Heat transfer occurs between the feed water temperature in the tube with extraction steam from the steam turbine and the drain of the Feed Water Heater on the top shell. Condensate Pump Condensate water is pumped by the deaerator through LPH 1, 2 and 3 respectively. Then the feed water is pumped by a Boiler Feed Pump (BFP) to the economizer to advance through the timber 5, 6 and 7. Another function of the heater is to improve the steam quality, which capture some steam at the turbine blade will reduce the wetness of steam, thereby reducing the effect of condensation heat transfer processes Most of the heater on the condensing section occurs. Although superheating made very high temperature, the heat transfer in desuperheating section remains small. Drain the cooling is the smallest part of the process of heat transfer in the heater.

Due to certain reasons such as tube leakage or leakage valve, feed water heater can be out of service (cut heater operation). In Design Manual Book (Hamen-Subelco Vol OI), the operation of the heater cut operation can be done with certain limitations. There are several parameters that must be observed particularly fibrasi problem and the maximum weight allowed when there are concessions in the out of service. However, the operation of the heater cut in a long time is not recommended because it will reduce the life time of the other heater. Turbine has been designed to anticipate the heater cut operation without overstressing the following conditions:
A. A condition
One or more non-contiguous heater (nonadjacent - one chasing turbine) can be out of service from the system.
Example: Heater 7, 5, 3 out of service. Load 100%
2. The condition B
If there is a heater that successive (adjacent) in the out of service then the load can still be maintained as long as there is above all the heater come on out of service.
Example: Heater 7, 6, 5 out of service. Load 100%
3. The condition C
Turbine heater can be operated with the highest in service and a combination heater out of service sequentially below. Load must be reduced 10% when there are 2 consecutive heater out of service, reduced 20% when there are three successive heater out of service. Reduction of the maximum allowable load is 50% of the nameplate. Loading beyond these limits is the responsibility of the owner.
Example: Heater 6, 5 out of service. Load 90%
Heater 6, 5, 3, 2 out of service. Load 90%
Heater 6, 5, 3, 2, 1 out of service. Load 80%

Related articles

• Clarification | of the actual design | and capacity | Condenser (human-style.blogspot.com)
• Electric Power Production Process (human-style.blogspot.com)

»»  NEXS...

Clarification | of the actual design | and capacity | Condenser

The condenser is a heat exchanger type of contact is not directly aimed at changing the steam from the turbine into the water so it can be re-circulated by the cooling method derived from seawater that is pumped by the CWP (circulating Water Pump).
Expenses received by the condenser can be calculated by the following formula:
P = Pg (HR/3600) - (104/ηm ηg)
where,
P = Load Condensor, kW
Pg = Electrical output, kW
HR = heat rate, kJ / kWh
ηm = Mechanical efficiency turbine-generaztor (approximately 99.5%)
ηg = Generator electrical efficiency (about 99%)
While the heat balance on the condenser can be calculated using the formula
Qcw = P / (cp (θ1 - θ2)
where,
Qcw = flow of cooling water, kg / s
P = load condenser, kW
Cp = specific heat, kJ / kg K
θ1 = temperature of cooling water into the condenser, C
θ2 = temperature of condenser cooling water exit, ° C

To clarify the design of the cooling capacity is needed, we must first know the condenser load (the energy that goes into the condenser) with a simple calculation using the formula: P = Pg (HR/3600) - (104/ηm ηg).
Turbine heat rate (HR) performance of data taken from test unit 2 of 1980 kcal / kWh (Appendix 1) at 300 MW load.
Pg = 300 MW
HR = 1980 kcal / kWh = 8290 kJ / kWh
P = 300 MW ((8290 kJ / kWh) / 3600) - (104 / (99 x 98))
P = 381.62 MW
Condenser load of 381.62 MW obtained. Clarification was required cooling capacity can be calculated using the heat balance in the condenser by the formula:
Qcw = P / (cp (θ1 - θ2)
Clarification of the cooling capacity required by the operational one CWP
θ1 = 26 ° C (temperature into the condenser with a pump CWP)
θ2 = 44 ° C (the temperature of the condenser with one pump out CWP)
cp = 4.08 J / kg K
Qcw = 381.62 MW / ((4:08 J / kg K) (44 oC - 26 oC)
Qcw = 5190 kg / s = 5.06 m3 / s
The actual flow flowing at 5:06 m3 / s flow capacity of the pump close to CWP. This proves that with a CWP able to load the actual unit of 300 MW but the consequences condenser outlet temperature of 44 oC.

Clarification of the required cooling capacity is based on two operational CWP (design)
Calculations can be performed using data from the design of the condenser inlet temperature and outlet temperature of the condenser.
θ1 = 26 ° C (the temperature of the condenser with two pumps into CWP)
θ2 = 34 ° C (the temperature of the condenser with two pumps out CWP)
Qcw = 381.62 MW / ((4:08 J / kg K) (34 oC - 26 oC)
Qcw = 11 678 kg / s = 11:39 m3 / s
Flow calculations for 11:39 m3 / s near the pump flow capacity of 2 CWP. So it is true CWP design 2 x 50% with the condenser inlet temperature of 26 ° C, the condenser outlet temperature is 34 oC.

Related articles

• Condensate | Treatment Plant (human-style.blogspot.com)
• Water cooling (ejrh.wordpress.com)
• The Process Of Nuclear Power (human-style.blogspot.com)

»»  NEXS...

Generator | Protection | Performance

Out-of-Synchronism occurs relatively rare in a large and robust power system, yet it may end up in an extensive and serious system disturbances, should it happen and persist for a long duration. To avoid such unexpected occurrences and in order to assure a good system security, a thorough and comprehensive study on generator protection is necessary.

In a system, which involves different users, the responsibility on system security should be borne by the grid participants and the system operator; and it ought to be based on a reference agreed by all.
The reference may concretely be realized in form of standard or agreement, or in form of rules agreed by the system users (grid code).
In many cases, not all matters in the code, especially those related to protection system coordination of the relays installed at the system operator’ side and that at the plant owner’s side, are well defined and fully understood.
The study here presented shall describe general condition of out-of-synchronism in a system and discuss the basic criteria that ought to be followed in defining the protection against out-of-synchronism.

 

In defining the criteria for the protection, some points should be considered: 1) asynchronous operation condition due to generator loss of field and 2) asynchronous operation due to system instability (out-of-synchronism).
Generator impedance varies as slip of generator relative to the system synchronous speed changes, and it will shift the electrical mid-point of the system-generator impedance. So, it will consequently influence the performance of generator protection.

Under-excitation operation of the generator will have, to some extents, no influence on the generator operation, unless it goes beyond the steady state stability limit.
Generally, the limits are given in the manufacturer’s manual.

In our study, the representation of generator’s current and voltage during the field current decrease (in parallel operation) is simulated in two conditions, as follows:

* decrease of generator’s e.m.f is not followed by rotor slip variation,
* decrease of generator’s e.m.f is followed by generator slip

Yet, in the real case, the field current decreases not linearly and the generator slip will also vary slightly during those interval. We should however bear in mind that the impedance locus moves towards the generator point.
The current decrease, that produces consequently new slip value, will take place when:
* decrease of the field current can not be sufficiently compensated by the under excitation limiter (UEL), or
* limit of the steady state stability is exceeded.

Those limits are generally determined based on the generator capacity to bear capacitive load, which is given by manufacturers.
In our study, the generator capacity has been taken from the loading curve of generator, determined by P (active power) and Q(reactive power) of the generator.

Related articles

• Cooling | Hydrogen (H2) (human-style.blogspot.com)
• Power Equipment Direct Announces Best Gas RV Generators (prweb.com)

»»  NEXS...

Furnace | Explosion

Basic Knowledge of Furnace Explosion
Furnace explosions are rare and unlikely. When compared with the total number of unit operating hours, the hours lost because of explosions are minimal. This desirable situation exists because (a) furnaces are supplied with an explosive accumulation only during a small percentage of their operating lives and (b) just a minute part of those explosive charges receive sufficient ignition energy to actually cause an explosion.
In suspension burning, the primary control of the combustion process is the admission rate of fuel and air to a furnace, independently of each other. The dynamic response of the combustion reaction, however, depends on the diffusion of the fuel and air to a flammable limit, and the elevation of this diffused mixture to its kindling temperature. The aerodynamic diffusion of fuel and air results from both the rate and method of admission. This admission flow pattern produces diffusion mechanically by inters rubbing of the fuel and air masses. Molecular diffusion is also present as a result of the elevated temperature level at which the combustion process takes place.

Furnace explosions result from a rapid rate of volume increase of the gaseous combustion products when too great a quantity of fuel and air reacts almost simultaneously in an enclosure with limited volume and strength. Avoiding furnace pressures in excess of furnace closure design pressure is, therefore, necessary to prevent furnace rupture.
The basis for any explosion-prevention system must be to limit the quantity of flammable fuel-and-air mixture that can exist in the furnace at any given instant. The rate of maximum pressure rise possible during the reaction is a function also of the available oxygen per unit volume of reactants. The effect of any oxygen density diluents (nitrogen, increased temperature, decreased pressure, excess fuel, inert gases) reduces the possible explosion pressure. Furnace-explosion prevention should be aimed at limiting the quantity of diffused flammable fuel-air mixture that can be accumulated in a furnace in proportion to the total volume and the mechanical strength of the furnace.
While fuel and air are being admitted to a furnace, there are only three possible methods of preventing excessive flammable diffused accumulations.
1. Igniting all flammable mixtures as they are formed, before their excessive accumulation.
2. Diffusing all flammable mixtures with sufficient additional air, prior to ignition, to a point beyond the diffused flammable-mixture ratio; and accomplishing this with a sufficient degree of diffusion before the flammable mixture occupies a critical percentage of the furnace volume.
3. Supplying an inert gas to diffuse simultaneously with the fuel and air, thereby diluting the oxygen content of the mixture below the flammable limit.
Implementation of these preventative methods requires operator action beyond the response, memory, and judgment capabilities of the normal operator controlling a plant in the manual mode. A fireside safeguard system must supervise the flow and processing of fuel, air, ignition energy, and the products of combustion. Satisfactory boiler operation requires that these four ingredients be properly prepared, ratioed, directed and sequenced so that the furnace cannot contain an explosive mixture. At supervised to check the results. Combustion must be kept efficient or the unconverted chemical energy may accumulate and subsequently become explosive.
The following factors influence the effective composition change of an explosive charge:
a) The facility for mixing
b) The inert material in the fuel
c) The fuel-air ratio
d) The kind of fuel
A furnace explosion requires both sufficient explosive accumulation within the furnace and sufficient energy for ignition.
The ignition requirements for an explosive charge are very small; making it impossible to protect against all possible sources of ignition, such as static electricity discharges, hot slag, and hot furnace surfaces.
Therefore, the practical means of avoiding a furnace explosion is the prevention of an explosive accumulation.
The potentially reactive furnace accumulation must be formed from an earlier buildup process which introduces reactive inputs not converted by oxidation to non-reactive or inert products. This buildup process must continue long enough to create a damaging accumulation. The accumulation composition, which must be within the limits of flammability for that particular fuel, is formed in one or more basic ways.
■ A flammable input into any furnace atmosphere (loss of ignition)
■ A fuel-rich input into an air-rich atmosphere (fuel interruption)
■ An air-rich input into a fuel-rich atmosphere (air interruption)
Furnace firing systems are designed to start up air-rich by introducing fuel into an air-filled furnace. Main fuel is introduced after the integral ignition system has satisfied permissive main-fuel interlocks that it can provide more ignition energy than the main fuel requires to be ignited or to remain ignited. Additional air is introduced around the primary-air/fuel mixture to take it beyond flammable limits, if it has not been ignited and reacted to inert combustion products; this is done to avoid a critical portion of the total furnace volume being occupied by a flammable mixture.

Related articles

• Dust from industrial-scale processing of nanomaterials carries high explosion risk (eurekalert.org)

»»  NEXS...

Sootblower Model PS-SL / PS-SB

Easy to Install
The sootblower mounts directly to
front and rear suspension points.
The suspension is designed to take
into account horizontal and vertical
expansion of the boiler wall.

Low Maintenance Design
The carriage travels along twin
guide rails driven by a robust rack
and pinion mechanism. Moving
parts are minimised. Easy
maintenance access is available to
all moving parts.

Minimised Spare Parts Stock
The PS series uses the same valve
as the Clyde Bergemann rotary
sootblowers, reducing overall parts
stock requirements.

Partial Retract Option
Where gas temperature permits,
this sootblower can also be
supplied in a partially retracting
configuration, reducing the exterior
projection of the sootblower from
the boiler.

Sectional Blowing Option
The sootblower may be specified to
blow over a limited blowing arc
where appropriate.

Choice of Wall Boxes
Positive pressure, negative
pressure and noise reduction
wallboxes are available to suit
installation conditions and
customer requirements.
Simple to Soundproof
Where sound emission
requirements are stringent, the
sootblower can be fitted with a
wallbox extension with sound
insulating rings to reduce sound
emissions from the nozzles.
Choice of Covers
Standard, extended and complete
enclosure covers are available to
suit installation conditions and
customer requirements.

Emergency manual operation
In the event of power failure the
sootblower can be operated
manually using the crank handle
provided.

Long Retractable Sootblower
Model PS-SL / PS-SB
Technical Data
Electric Motor
One 0.55 kW (0.37 kW for PS-SB) 3 phase flange mounted totally enclosed for
safe area environments. Explosion proof specification available for hazardous
areas.

Material Specifications
Lance tube material…………………...………………..chrome molybdenum steel
or special steels to suit boiler conditions
Feed tube material……………………………………... …………….stainless steel
Valve material…………………………………………...chrome molybdenum steel
class 300 or 600 to suit conditions
Flange
DN80 PN63 to standard DIN 2546. Other flange types available on request.

Related articles

• Mercedes-Benz provides an update on the electric drivetrain of the SLS AMG E-CELL (greencarcongress.com)

»»  NEXS...

Cooling | Hydrogen (H2)

Image via Wikipedia

DSC_7636-mb-hydrogen-store (Photo credit: swh)Generator is designed to be able to survive in conditions of normal working temperatures of up to working temperature is abnormal, for example: during a short circuit current.
For the same dimensions, the ability to withstand heat will determine the output power rating to withstand the heat that is owned generator.Kemampuan determined two factors: a. Isolation level
b. Cooling rate (ability to dissipate heat)
Heat that caused the generator caused by loss - loss of power (power losses) consisting of:
- Loss - loss of copper / loss - loss of power
- Loss - loss of iron / loss - loss of magnet
- Loss - loss of mechanical

Generator with output power ratings above 300 MVA-Ugi has lost about 1%. Loss - the loss in the form of heat. To keep the heat does not damage the insulating mechanical generator systems listrikdan the pans should be channeled out / absorbed from the generator. Functions performed by the heat absorption refrigeration system.
Steam turbine generator PLTGU Freshwater Estuary using a generator with output power rating of 200 MVA (288 MVA) so that the media selection hydrogen gas (H2) as a coolant is appropriate. Media selection hydrogen gas (H2) as a refrigerant is based on:
A. The density of Hydrogen is only 1/14 times the density of air at the same pressure and temperature. The use of hydrogen gas will reduce the losses - losses due to friction wind generator and sound (noise).
2. Heat transfer capability of hydrogen gas in the system of forced convection (forced convection) 1.5 times the amount of air the heat transfer capability.
3. For the same mass, the heat absorbing capacity of 14.5 times the amount of hydrogen gas of air, because at the same temperature and pressure of the mass of hydrogen is only 1/14 times the mass of air. Then the magnitude of the heat capacity of hydrogen: 14.5 / 14 = 1.035 times the heat-absorbing ability of the air at the same temperature and pressure. So better cooling hydrogen gas from the air.
4. Hydrogen gas does not occur on oxidation reactions and impurities so the generator insulation life will be longer.
5. The thermal conductivity of hydrogen gas air 7 times.
6. In the high-speed machines such as generators, loss - loss of wind is calculated as part of the loss - a total loss, because the density of hydrogen of about 7% more dense than air. Loss - loss of air-cooled hydrogen generator is reduced to 10% of air-cooled generator, so that the generator efficiency is increased by 1%.
The use of hydrogen gas media will reduce the heat to be removed and at the same time will increase the ability to dissipate heat from the generator.
The selection of media as a medium for cooling the hydrogen gas should be noted that - as follows:
a. Hydrogen gas is a gas that is very dangerous (explosive) that require special handling. Concentration of 4-76% hydrogen gas in the air is an explosive mixture (mixture explosivi). Hydrogen gas purity must be guarded / secured at a high level.
b. Require special handling in the process of charging and discharging hydrogen gas from the generator.
c. Requires two systems Auxillary namely:
- Seal oil system: to maintain the hydrogen gas remains in the generator.
- Gas system / Hydrogen plant: to maintain the pressure and purity of hydrogen gas.

Generator cooling circulation system can be viewed as shown below:

picture Hydrogen Gas Circulation
Generators and water cooled heat exchanger must be insulated hydrogen gas terahadap meeting. The main problem that occurs in isolation bearings which can be space / narrow gap between the rotor and the generator body is not moving. Spaces / narrow gap that allows its happening kebocorangas the hydrogen to the outside air pressure is smaller. This is very dangerous because it can cause an explosion and fire. To overcome the space / narrow gap is closed with a coating of oil / oil seal oil system is required.
To prevent the mixture that is explosive in the combustion chamber pressure is maintained so that hydrogen gas is greater than the outside air pressure so that when the hydrogen gas leak will point out.
Minimum pressure of hydrogen gas to the outside air is 3440 N/m2 (0.0344 barg). At this pressure the maximum output power rating of the generator can be increased by about 30% above the rating of air-cooled generator. While the peak efficiency (full load efficiency) rose about 0.5%. Tend to use hydrogen gas pressure is higher (between 1.03 barg s / d 4.13 barg) to mass of hydrogen gas generator in a larger space so that the heat absorbing capacity increases. Raising the hydrogen gas pressure of 0.0344 to 1.03 barg barg will increase the output (for the same rise in temperature) of about 15%. Hydrogen gas pressure increases from 0.0344 to 2.07 barg barg would raise output (for the same temperature increase) by 25%. Methods to improve the ability to absorb heat from the generator is to develop a conductor cooling / cooling liner.

Related articles

• How to generate Hydrogen from you tap water? (ahilan007.wordpress.com)
• HyperSolar harnesses sunlight to produce cleaner-than-clean hydrogen fuel (gizmag.com)

»»  NEXS...

Condensate | Treatment Plant

In the high velocity mixed bed treatment system, the regenerative cation and anion resin having high exchange capacity are mixed thoroughly with a certain proportion. Then they are put into the in extraneous regenerative high velocity mixed bed to carry on demineralization treatment.
The high-rate mixed bed system of this project has 2×50% treatment capacity. When one exchanger loses efficiency, it will open the 50% bypass automatically, and it will be put into operation again after it has being regenerated. When the pressure difference or water inlet temperature of the mixed bed main pipe is beyond the standard, the 100% bypass will be opened automatically.

For the condensate treatment of this project, one unit is allocated one set of high velocity system, and the resin extraneous regeneration system is communal. Every set of high velocity system is made up of 2 DN2200 extraneous regeneration high-velocity mixed beds and 2 recycle pumps. Resin extraneous regeneration system is mainly made up of resin separation equipment, resin regeneration equipment and electric heating water tank.
System operating mode:
There are two bypasses opened and closed automatically in condensate polishing system (beside regeneration bypass and super temperature super pressure bypass). The capacity of regeneration bypass is 50% of the condensing capacity, and the capacity of regeneration bypass and super temperature super pressure bypass is 100% of the condensate capacity.
When the water outlet conductivity or silica of the condensate polishing mixed bed is over the specified value, the equipment stop and step out, and the regeneration bypass is placed in operation.
When the water inlet temperature of condensate polishing is more than 55℃ or the pressure difference of mixed bed inlet and outlet is over 0.35MPa, all operation unit of the mixed bed stop, and the super temperature super pressure bypass is placed in operation.
The failure resin of stopped mixed bed is sent to regeneration system to be air scrubbing, to be separated, and to be regenerated. Send the regenerated standby resin inside the resin storage tank to high velocity mixed bed.
The startup of mixed bed, shutdown of mixed bed, resin transmission, resin regeneration of condensate polishing system can all be carried on automatically.

Related articles

• Definitely D (artoftrolling.memebase.com)
• Rasayan (slideshare.net)

»»  NEXS...

System and Equipment | of Water Treatment

Image via WikipediaThe water source of power plants

Water is one of the most important natural resources which is covering about 3/4 surface of the earth. The natural water includes underground water and surface water. The underground water comes from the surface water which seeps underground. It has high hardness and stable quality hardly influenced by seasons and surroundings. Surface water includes water in rivers, lakes, reservoirs and seas.
Water in rivers and lakes comes from rain, it has lower hardness and salt content than underground water, it is not stable and easy influenced by seasons and surroundings. Water in lakes and reservoirs is similar with that in rivers, it has lower turbidity than that in rivers because of the lower flowing characters. But it is good for microorganism growing.
Water in sea has large quantity of dissolved salt, such as sodium chloride, because of the long time evaporation and concentration.

The classification of water in power plants
Water in power plant has different characters and functions, they can be classified as: raw water, make-up water, boiler water, condensate water, drain water, cooling water, saturated steam and superheated steam.
Main method of make-up water treatment
Natural water contains impurities that will lead to scale deposit, corrosion, salt deposits in the thermal system, and consequently threat the safety and economics of the power plant.

Make-up water treatment is one of the most important treatments in a power plant. Water with different impurities needs different treatment.
The organics, suspensions, colloid and part of the hardness can be eliminated by chlorination, coagulants and clarification. These methods are usually the first step of water treatment in power plants, we call it pretreatment. The dissolved solid can be eliminated by ion exchange, electrolysis, reverse osmosis and distillation. The dissolved gas can be eliminated by thermal method, such as deaerator, chemical method and gas-liquid exchange.
The Pretreatment of Make-up Water Filtration
When an electricity factory uses the tap water as the water resource, the pretreatment system is simple. It is like this flow: tap water cleaning water activated carbon filter cation exchanger anion exchanger mixing bed demineralized water tank main building.
Even with some clarifiers operating at optimum levels under anticipated conditions, additional solids-removal equipment is required downstream. It serves to reduce the remaining suspended solids, colloids and remnant chloride to the parts-per-billion level required for the boiler operation.
Filtration is a process of placing a pervious barrier across flowing water to remove suspensible matter. It can be accomplished simply through mechanical straining at the surface of the barrier or by removal throughout the depth of the medium.
Proper performance does not begin until a layer of silt and bacterial matter has developed in the top inch or so of sand. This unit then produces exceedingly clear water, but at a rate no faster than 0.008m/s is reached. The upper layer, where all the filtering action takes place, is then scraped off, washed externally, and restored to the bed.
There are many factors to have influence on the process, such as filter medium, filter speed, water head loss, flow uniformity and reverse-flow backwash.
Filter medium, such as active carbon, is the basic unit of filtration. Choose of the proper medium is important to running efficiently. The medium must have these characters: good stable chemical character, enough mechanical strength, proper and uniform size and proper medium layer height.
If the speed of filtration is too slow, the output is limited. On the contrary, it will lead bad outlet water quality, higher loss of water head and short operating cycle.
Water head loss is an important parameter to judge whether the filter is scraped off. When the water head loss reaches to a certain value the filter should be put into outage and cleaned by reverse-flow backwash.
There are two types filter used in power plants: gravity type, such as valveless filter, and pressure type.
The Demineralization Treatment of the Make-up water
The ion-exchange demineralization treatment is that the cation-exchange resin exchange the cation in water to H+, the anion-exchange resin exchange the anion to OHˉ,and the undissociated water molecules are the end product. By the way the ion exchangers are named not for what they are but rather for what they do. There are different demineralization treatment systems with strong and weak electrolyte ion to adapt different demands of water quality such as primary demineralization treatment system and secondary demineralization treatment system (mixing bed).
Primary demineralization treatment system
The individual cation-exchange resin bed is the ion-exchange unit which the water encounters first. The cations, such as sodium and calcium, are removed by exchange with hydrogen ions from the resin.
The individual anion-exchange resin bed is the second ion-exchange unit the water encounters. The anions, such as silicate and carbonate, are removed by exchange with hydroxylions from the resin.
The aerating tower is used for eliminating the dissoluble gas from water, such as carbon dioxide and oxygen.
To get high quality make-up water, the mixing bed is needed. The cation and anion resin are mixed thoroughly in one bed with a certain proportion. The exchange of both ions happens simultaneously, and the outcome ions interact to form undissociated water molecules. The mixing bed produces high quality water which electrical conductivity approaches ideal pure water.

Makeup water system and its devices in Phase II of Kuching Power Station
According to the quality of the water resource and the requirement of the steam and water by the unit, the flow of the makeup water system is:
Tap water→clarified water tank→clarified water pump→active carbon filter→cation exchanger→anion exchanger →mixed bed→demineralized water→demineralized water pump→main building
The technical process of the treatment system is the same as in Phase I.
In Phase I of Kuching Power Station there are two active carbon filters and two demineralized devices with output of 26m /h. An active carbon filter and a set of demineralized devices are added in Phase II, to satisfy the requirement of the makeup water quantity by 4 units in the station. The parameters of the new supply devices are the same as that in Phase I, its output is 26 m /h; the designed operation period of the cation-exchanger and anion-exchanger is 41 hours, the operation period of the mixing exchanger is 13 days; cation resin adopts 30% of hydrochloric acid regenerating, and anion resin adopts 50% of sodium hydroxide regenerating.
The extended water treatment system possesses 3 sets of devices with two sets operating and one as standby.
The devices supplied in Phase II are as follows:
An active carbon filter; a cation-exchanger; an anion-exchanger; a mixing bed
Two demineralized water tank with each capacity of 150 m

Related articles

• WaterProfessionals Acts Fast to Restore Construction Timeline for New Utilities Building at University of Massachusetts (prweb.com)
• The Combination of Seaweed and Active Sludge Biofilter As a Water Treatment Supply Facilities on the Fish Rearing (romitisam.wordpress.com)

»»  NEXS...

Water Treatment | Plant

In the process plant, in addition to require coal as a fuel, it also requires a certain quality of water as boiler feed which in turn is converted into steam to drive turbine generators. For the purposes of water which will then be made specific to the power plant water treatment facilities. Content of salts are usually always there, Bicarbonate, HCO3; Chloride, Cl; Sulfate, SO4: NO3 nitrate of calcium, Ca; magnesium, Mg, and sodium, Na. There is also an iron, Fe; Manganese, Mn and aluminum, Al.

To get water that meets the requirements for steam boilers (boiler) in a Steam Power Plant (power plant) is required Water Treatment. There are two ways of processing, namely;
• Processing is carried out Boiler (external treatment).
• Processing in the Boiler (internal treatment).

REVERSE OSMOSIS Picture

Distillation Method
In this method the modified salt water into fresh water. The principle is very simple: by heating the sea water and steam in the chill returned. To make fresh water from sea water in large quantities. Sea water is introduced into the vessel and heated by steam through the steam pipe. Hot steam is passed through a boiling sea water pipe. Because of this heat effect of sea water began to evaporate. Sea water vapor put into the second vessel is equipped with cooling water installations. Heat absorbed by water vapor condenses to form salt and raw water. This process will occur on a problem that is the formation of crust on the surface of the metal (pipe). The crust is hard and difficult to remove and also a poor conductor of PNAS. To overcome this metal surfaces coated with Teflon.

Demineralization way
Of salt water can also be eliminated by using the ion. Ion exchange unit is equipped with sand filters. Penukat ion exchanger consists of cation and anion exchangers. Cation exchanger that takes the positive ions from the water and the anion exchanger to take the negative ion of water. This exchanger is a resin material which can be activated in an already saturated after regenerated. Cation exchanger regenerated with sulfuric acid (H2SO4) is an anion exchanger is regenerated with sodium hydroxide (NaOH).

»»  NEXS...