Laporan Kerja Praktek di PT BASF Care Chemicals Plant Cimanggis. Membahas beberapa metode perancangan dalam proyek Sulfation Debottlenecking. Peralatan yang masuk di dalam perancangan ini ada 2, ya...
Laporan Kerja Praktek di PT BASF Care Chemicals Plant Cimanggis. Membahas beberapa metode perancangan dalam proyek Sulfation Debottlenecking. Peralatan yang masuk di dalam perancangan ini ad…Full description
materi tentang pendingin mesin dengan media oli pelumasFull description
Cooler Design
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materi tentang pendingin mesin dengan media oli pelumasDeskripsi lengkap
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The report includes design and results of performance test carried out on air cooler cum water chiller .
ACDeskripsi lengkap
Temperature control is defined as to maintain the temperature at desired set point. It is widely used process. In modern era temperature control is an important factor as it has many applications. Automatic temperature control is the best way to cont
This document explain about the standard procedure for Operating & Maintenance Procedure of Air Cooler Heat Exchanger as per international standard
This document explain about the standard procedure for Operating & Maintenance Procedure of Air Cooler Heat Exchanger as per international standard
Project Holder-Mr. Girish Bhalchandra Amrutkar (BE Mechanical, MBA )
AIR COOLER EXCHANGERS
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What is an air cooler?
Air-cooled exchangers use atmospheric air on the outside of high-finned tubes (except bare tubes are used in a few applications) to cool or condense fluids flowing through the inside of the tubes.
This type of exchanger is used to reject heat from a fluid inside the tubes directly to ambient air.
To be effective, the air must flow in forced convection to develop acceptable transfer coefficients.
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Two Types of Air Coolers
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Induced Draft Advantages:
Better distribution of air across the bundle.
Less possibility of hot effluent air recirculating into the intake. The hot air is discharged upward at approximately 2.5 times the intake velocity, or about 1,500 ft per min.
Better process control and stability because the plenum covers 60% of the bundle face area, reducing the effects of sun, rain, and hail.
Increase capacity in the fan-off or fan-failure condition, because the natural draft stack effect is much greater.
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Disadvantages and limitations:
Possibly higher horsepower requirements if the effluent air is very hot.
Effluent air temperature should be limited to 220°F to prevent damage to fan blades, bearing, or other mechanical equipment in the hot airstream. When the process inlet temperature exceeds 350°F, forced draft design should be considered because high effluent air temperatures may occur during fan-off or low air flow operations.
Fans are less accessible for maintenance, and maintenance may have to be done in the hot air generated by natural convection.
Plenums must be removed to replace bundle
Hudson states that the advantages of the induced draft design outweigh the disadvantages.
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Forced Draft Advantages:
Possibly lower horsepower requirements if the effluent air is very hot. (Horsepower varies inversely with the absolute temperature.)
Better accessibility of fans and upper bearings for maintenance.
Better accessibility of bundles for replacement.
Accommodates higher process inlet temperatures
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Forced Draft Disadvantages:
Less uniform distribution of air over the bundle.
Increased possibility of hot air recirculation, resulting from low discharge velocity from the bundles, high intake velocity to the fan ring, and no stack.
Low natural draft capability on fan failure.
Complete exposure of the finned tubes to sun, rain, and hail, which results in poor process control and stability.
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Air Cooler Sections in Details:
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Bay is a part or entire of air cooler that may include one or several tube bundles with at least one fan.
Based on EXXON Design Practice Section IX-I page 4: Bundles may be fabricated in widths up to 16 ft (4.9 m) and depths up to 10 rows.The most common tube length is 30 ft (9 m) although bundles are available in lengths from 8 to 60 ft (2.4 to 18.3 m).
Also according to IPS-E-PR-785 item 6.6: Bundles may be fabricated in widths to 3.65 m (12 ft) and depths to 8 rows.
IPS-E-PR-785 item 8.1:At least two fans shall be provided for each bay.
According to EXXON Design Practice Section IX-I: Tubes for air-cooled heat exchangers may be plain or may contain fins.
The fin density varies between 7 and 11 fins/in. (276 and 433 fins/m) and fin height varies from 5/16 to 1 in. (8 to 25 mm).
The minimum acceptable tube diameter is 1 in. (25 mm).
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Fin Types • The L-footed tension wound fin is normally used in services where the tube wall temperature does not exceed 350 degrees F and air side corrosion is not extremely high.
• In high temperature applications, an embedded process is employed to attach the fin to the tube wall. • The embedded fin is normally used for services greater than 350 degrees F and less than 750 degrees F.
For applications where atmospheric corrosion is critical, the extruded fin tube provides the best protection.
The extruded fin tube is good for tube wall temperature up to 650 degrees F. This is the most expensive fin tube to produce. ١٠
Other Points • Under normal operating conditions, air outlet temperatures should not Exceed: 60°C with fans in operation. 80° C with free convection on the air side. • Fouling factor on air side of exchangers shall be 0.35m2. K/kW (0.002h.ft2.°F/Btu) , For fresh water cooling system the fouling factor shall be 0.0004 hr. °C m2/ kcal. • Design maximum ambient air temperature should be selected so that it will not be exceeded more than 1-2 percent (sometimes 2-5%) of the total annual hourly readings based on at least 5 consecutive years. • Units should not be located near heat sources. Experience cautions that units near exhaust gases from engines can raise inlet air 8°C or more above the expected ambient
