Jumat, 02 September 2011

1 Spesifikasi Model Water Heater F

Orientasi: Vertikal
Instalasi: Lantai Mounted
Persyaratan Ruang: 7 sq.ft.
Sertifikasi: Bagian VIII ASME
Shell Bahan: Besi cor
Shell Penilaian
    F30 & F60: F90 & F120:
75 psi @ 350 o F
50 psi @ 300 o F
Coil Penilaian
    F30 & F60: F90 & F120:
200 psi @ 350 o F
200 psi @ 300 o F
Coil Bahan: Tabung Tembaga SB75
Coil Ukuran
    F30/F60/F90: F120:
0,5 "OD 18 BWG
0,625 "OD 18 BWG
Tekanan Drop:
Pemanas air InstaFlow dirancang dengan penurunan tekanan air dihitung sekitar 8 psig antara pasokan air dingin dan air panas outlet.
Air Suhu Ideal Jangkauan Pengoperasian: 105-185 o F
Perangkap Kondensat Utama: F & T Jenis
Drip Perangkap: Termostatik Jenis
Uap Tekanan Gauge: 30 "Hg - 30 psig
Air Gauge: 70-270 o F, 0-200 psi
20-120 o C, 0-1400 kPa
Frame: Baja Besi Sudut
Pelindung Kain Kafan: 20GA Baja Galvanis
Isolasi: 2-lb. Kepadatan Fiberglass
Jaminan
    Shell: Coil:
10 Tahun
10 Tahun
Berat Pengiriman (lbs.):
    F30: F60: F90: F120:
320
405
450
615

0 Large Steam System Condensers

Heat Exchanger Knowledge | Heat Exchanger Companies Suppliers

Steam condenser, shown in Figure 9 below, are the main components of the steam cycle in power generation facilities. This is a closed chamber in which steam turbine and is forced to give up its latent heat of vaporization. This is an important component of the steam cycle for two reasons. One, it changes the steam back into water that is used to return to the steam generator or boiler as feed water. This lowers operating costs by allowing the plants clean and treated condensate to be reused, and it's much easier to pump liquid from vapor. Two, increase the efficiency of the cycle by cycle makes it possible to operate with the greatest possibility of delta-delta-T and P between the source (boiler) and heat sink (condenser).

Since the condensation takes place, the latent heat of condensation term used instead of latent heat of vaporization. Latent heat of condensation of steam is passed into the water flowing through the condenser tubes.

After the steam condenses, saturated liquid continues to transfer heat to the cooling water as it falls to the bottom of the condenser, or hotwell. This is called subcooling, and a certain amount desired. A few degrees subcooling prevents condensate pump cavitation. The difference between the saturation temperature for an existing vacuum condenser and the condensate temperature is called condensate depression. This is expressed as the number of degrees of depression or degrees subcooled condensate. Excessive condensate depression decreases the efficiency of plant operations due to subcooled condensate must be heated in a boiler, which in turn requires more heat from the reactor, fossil fuels, or other heat sources.
There are different condenser designs, but the most common, at least in large power generation facilities, is a straight-through, single-pass condenser illustrated Figure 9 above. Condenser design provides cooling water flow through a tube directly from the inlet water box on one end, into the water box out at the other end. The cooling water flows once through the condenser and the so-called single pass. The separation between the box and the condensation of water vapor carried by the tube sheet in which the cooling water tubes are attached. Cooling water tubes are supported in the condenser with a tube sheet support. Condensers normally have a series of baffles that direct the steam to minimize direct impingement on cooling water tubes. Area under the condenser is hotwell. This is the place to collect the condensate and the condensate pump takes its suction. If noncondensable gases are allowed to build in the condenser, vacuum will be reduced and the saturation temperature at which vapor will condense increases.

Non-condensable gas is also blanket the condenser tubes, thereby reducing the heat transfer surface area of ​​the condenser. This surface area can also be reduced if the level of condensate is allowed to rise above the lower tube of the condenser. Decrease the heat transfer surface has the same effect as reducing the flow of cooling water. If the condenser operating near design capacity, a reduction in the effective surface area results in difficulty maintaining condenser vacuum.

Temperature and flow rate through the condenser cooling water temperature control of the condensate. This in turn controls the saturation pressure (vacuum) of the condenser. To prevent condensate from rising to levels below the condenser tube, hotwell level control system can be used. Varying the current from the condensate pump is one of the methods used to improve control hotwell level. A level sensing network controls the condensate pump speed or pump discharge flow control valve position. Another method uses overflow system that spills water from hotwell when high level is reached.

Vacuum the condenser must be maintained as close to 29 inches Hg practical. This allows maximum expansion of steam, and therefore, to work optimally. If the condenser is perfectly air-tight (no air or noncondensable gases present in the exhaust steam), will be necessary only to condense the steam and remove the condensate to create and maintain a vacuum. Sudden drop in the volume of vapor, like condenses, will maintain the vacuum. Pumping water from the condenser as fast as formed will maintain the vacuum. However, it is impossible to prevent the entry of air and other noncondensable gases into the condenser. In addition, there must be some method to initially cause a vacuum in the condenser. This requires the use of an air ejector or vacuum pump to establish and help maintain condenser vacuum.

Basically jet air ejector pumps or eductors, as illustrated in Figure 10 below. In operation, a jet pump has two types of liquids. They are high pressure fluid flowing through the nozzle, and fluid being pumped which flows around the nozzle into the diffuser throat. High-speed fluid into a diffuser where the molecules that attack other molecules. These molecules in turn carried away by high speed liquid out of the diffuser creating a low pressure area around the mouth of the nozzle. This process is called entrainment. Lowpressure area will draw more fluid from the nozzle into the diffuser throat. As the fluid moves down the diffuser, the increasing speed of converting back to the pressure. The use of steam at a pressure between 200 psi and 300 psi for high pressure fluid enables singlestage air ejector to draw about 26 inches Hg vacuum.
Normally, air ejectors consist of two stages suction. Suction first stage is located above the condenser, while the second stage suction comes from the diffuser of the first stage. Exhaust from the second stage must be condensed. This is usually accomplished by the air ejector condenser which is cooled by the condensate. Air ejector condenser also preheats the condensate return to boiler. Two-stage air ejectors able to draw vacuums to 29 inches Hg.

A vacuum pump may be all kinds of motor-driven air compressor. Suction is attached to the condenser, and the release into the atmosphere. A common type uses rotating vanes in the housing ellipse. Single-stage, rotary-vane units are used for vacuums to 28 inches Hg. Two stage units can draw vacuums to 29.7 inches Hg. Vacuum pumps have the advantage over air ejector in that it requires no source of steam for the operation. They are usually used as the initial source of vacuum for condenser start-ups.



 
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