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HEAT EXCHANGERS
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PDEC
INDIAN OIL CORPORATION LTD PROCESS DESIGN ENGINEERING CELL(PDEC)HEAT EXCHANGERS DESIGN & MANUFACTURING FEATURES BY M. BALA1
CONTENT DEFINITION OF HEAT EXCHANGERS TYPES OF HEAT EXCHANGERS
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CLASSIFICATION OF SHEEL AND TUBE HEAT EXCHANGERS DIFFERENT TYPES OF HEAT TRANSFER EQUIPMENTS2
CONTENT COMPONENTS OF SHELL AND TUBE HEAT EXCHANGERS NOMENCLATURE OF HEAT EXCHANGERS CONSTRUCTION OF HEAT EXCHANGERS
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CONTENT CODES/ STANDARDS DESIGN OF HEAT EXCHANGERS MATERIAL IDENTIFICATION CHART SELECTION OF HEAT EXCHANGERS TYPES
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CONTENT THERMAL DATA SHEET OF HEAT EXCHANGERS MECHANICAL DATA SHEET OF HEAT EXCHANGERS MANUFACTURING FEATURE MAINTENANCE OF HEAT EXCHANGERS
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HEAT EXCHANGERS DESIGNDEFINITION OF HEAT EXCHANGER: A heat exchanger is a piece of equipment built for efficient heat transfer between a hot process stream and a cold process stream.
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HEAT EXCHANGERS DESIGNTYPES OF HEAT EXCHANGERS: Shell & Tube heat exchanger Plate heat exchanger Plate & Shell heat exchanger
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HEAT EXCHANGERS DESIGNSHELL AND TUBE HEAT EXCHANGER
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Shell & tube heat exchangers consist of a series of tubes & cylindrical shell. One set of these tubes contains the fluid that must be either heated or cooled. The second fluid runs over the tubes i.e inside the shell that are being heated or cooled. A set of tubes is called the tube bundle.(as shown in Fig).8
HEAT EXCHANGERS DESIGNSHELL AND TUBE HEAT EXCHANGER
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COMPLETE HEAT EXCHANGER
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HEAT EXCHANGERS DESIGNPLATE HEAT EXCHANGER
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It is composed of multiple, thin, slightly separated plates that have very large surface areas and fluid flow passages for heat transfer. Much higher heat transfer co-efficient Lower cost, low space requirement
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PLATE HEAT EXCHANGERS
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HEAT EXCHANGERS DESIGNPLATE AND SHELL HEAT EXCHANGERS It is combines with plate heat exchanger and shell & tube heat exchanger technologies. High heat transfer, high pressure, high operating temperature Compact in size
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HEAT EXCHANGERS DESIGNPLATE AND SHELL HEAT EXCHANGERS
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HEAT EXCHANGERS DESIGN
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TYPE OF SHELL AND TUBE HEAT EXCHANGERS Shell and Tube Heat Exchangers (STHEs) are the most widely and commonly used unfired heat transfer equipment in the chemical process industries. Shell and tube heat exchanger may be classified By construction and By service15
HEAT EXCHANGERS DESIGNHEAT EXCHANGERS NOMENCLATURE: An STHE is divided into three parts mainly: The front head The shell and The rear head
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TEMA DESIGNATIONS FOR SHELL-AND-TUBE. HEAT EXCHANGERS
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HEAT EXCHANGERS DESIGNHEAT EXCHANGERS NOMENCLATURE:
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There are five front head types: A, B, C, D and N. There are eight rear head types: L, M, N, P, S, T, V, and W which corresponding in practice to only three general construction types, namely fixed tube sheet, U-tube and18
HEAT EXCHANGERS DESIGNCont: Rear head L is identical to a front head A and rear head M is identical to a front head B while N is the same nomenclature. There are seven types of shell depending on fluid flows through a shell - E, F, G, H, J, K and X.
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HEAT EXCHANGERS DESIGN CLASSIFICATION BY CONSTRUCTION It may be classified into three categories. Fixed-tube sheet heat exchanger U-tube heat exchanger Floating- head heat exchanger
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HEAT EXCHANGERS DESIGNFIXED-TUBE SHEET HEAT EXCHANGER
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A fixed-tube sheet heat exchanger has straight tubes secured at both ends to tube sheets welded to the shell.
The construction may have removable channel covers (e.g. AEL), bonnet type channel covers (e.g.21
HEAT EXCHANGERS DESIGNFIXED-TUBE SHEET HEAT EXCHANGERBonnet Stationary (Stationary Tubesheet Head) Support Bracket Stationary Tubesheet
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Bonnet (Stationary Head)
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HEAT EXCHANGERS DESIGNFIXED-TUBE SHEET HEAT EXCHANGER
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Advantages of this exchangers The main advantage of a fixed-tube sheet construction is low cost as it has the simplest construction. Permits mechanical cleaning of the inside of the tubes as these are accessible after removal of the channel cover or bonnet.23
HEAT EXCHANGERS DESIGNFIXED-TUBE SHEET HEAT EXCHANGER
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No leakage from the shell side fluid as there are no flanged joint. Disadvantages of this exchangers The outside of the tube can not be cleaned mechanically as the bundle can not be removed from the shell. Due to this shell side fluid should be clean24
HEAT EXCHANGERS DESIGN
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U-TUBE HEAT EXCHANGER As name implies, the tubes of a Utube heat exchanger are bent in the shape of a U. There is only one tube sheet in a U-tube heat exchanger.
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HEAT EXCHANGERS DESIGN
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U-TUBE HEAT EXCHANGER Advantages of this exchangers It permits the tube bundle to expand or contract according to the differential stress set up due to free at one end. It permits the outside of the tubes cleaning as the tube bundle can be removed.
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HEAT EXCHANGERS DESIGN
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U-TUBE HEAT EXCHANGER Disadvantages of this exchangers The inside of the tube cannot be cleaned effectively. This exchangers should not be used for services which have dirty fluid inside the tubes.27
HEAT EXCHANGERS DESIGNU-TUBE HEAT EXCHANGER
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It places a very severe limitation on U-tube heat exchangers for refinery services, which usually have dirty streams on both the tube side and shell side. This is primarily the reason why U- tube heat exchangers are not generally used in oil refineries .28
HEAT EXCHANGERS DESIGN
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FLOATING- HEAD HEAT EXCHANGER A Floating-heat exchanger is one where one tube sheet is fixed relative to the shell and the other is free to float within the shell.
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HEAT EXCHANGERS DESIGN
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FLOATING- HEAD HEAT EXCHANGER Advantages of the exchangers This type of heat exchanger permits free expansion of the tube bundle It permits cleaning of both the inside and outside of the tubes. It is used for services where both the shell side and tube side fluids are dirty.30
HEAT EXCHANGERS DESIGN
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FLOATING- HEAD HEAT EXCHANGER Floating head exchanger is the most versatile construction. Disadvantages of this exchangers It is more costlier than Fixed tube & Utube exchangers due to: More components in this construction Shell diameter is larger than floating tube sheet.31
HEAT EXCHANGERS DESIGNFLOATING- HEAD HEAT EXCHANGER
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Various types of floating head construction are: Pull through with backing device:TEMA type S Pull through: TEMA type T Outside- packed stuffing box: TEMA type P32
HEAT EXCHANGERS DESIGN PULL THROUGH WITH BACKING DEVICE: TEMA type S
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Most commonly used type in the chemical processing industries. The floating head cover is secured against the floating tube sheet by bolting it to an ingenious device called split backing ring. The floating head closure is located beyond the end of the shell and33
HEAT EXCHANGERS DESIGN
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Cont. For dismantling the heat exchanger, the shell cover is removed first, then the split backing ring and finally the floating head cover after which the tube bundle can be removed from the stationary end. For assembling the heat exchangers, the reverse order is followed.34
HEAT EXCHANGERS DESIGNPULL THROUGH WITH BACKING DEVICE: TEMA type S
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HEAT EXCHANGERS DESIGNPull through: TEMA type T The floating head cover is bolted directly to the floating tube sheet so that a split backing ring is not required. The advantage of this type construction is that the tube bundle may be removed from the shell without removing either the shell or floating head cover.
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HEAT EXCHANGERS DESIGNPull through: TEMA type T
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It is generally used for kettle reboilers having a dirty heating medium where u-tube cannot be used. The shell diameter is the largest in this type of construction since floating head tube sheet with cover has to be removed through the shell. Hence, the cost is the highest
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HEAT EXCHANGERS DESIGN Pull through: TEMA type TR e a r tu b a d e n d1 1 1
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S h e ll11 11
S ta tio n a ry H ead end
1
1 1 1
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HEAT EXCHANGERS DESIGN
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OUTSIDE-PACKED STUFFING BOX:TEMA TYPE P In this construction, the shell side fluid is sealed by ring of packing compressed within a stuffing- box by a follower ring. This construction is prone to leakage. Due to this, its usage is limited to shell side services, which are: Non-hazardous and non-toxic services 39
HEAT EXCHANGERS DESIGNOUTSIDE- PACKED STUFFING BOX: TEMA TYPE P11 11
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11 11
1 1
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HEAT EXCHANGERS DESIGNOUTSIDE-PACKED LANTERN RING: TEMA TYPE W
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The shell side and tube side fluids are sealed by separate ring of packing or O-ring and separated by a lantern ring provided with weep holes. Hence any leakage will be the outside. The width of the tube sheet necessarily has to be sufficient to accommodate the two packing rings and the lantern ring, plus the 41
HEAT EXCHANGERS DESIGN
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OUTSIDE-PACKED LANTERN RING: TEMA TYPE W This design is limited to 9.9 kg/cm and 204c.11 11 1 1 11 1
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HEAT EXCHANGERS DESIGN
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CLASSIFICATION BY SERVICE It may be classified into four categories. Single phase (both shell side and tube side) Condensing (one side condensing and other single phase) Vaporizing ( one side vaporizing and the other single phase) Condensing/vaporizing (one side condensing and the other vaporizing)43
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DIFFERENT TYPES OF HEAT TRANSFER EQUIPMENTS Heat Exchanger: both side single phase process streams (that is not an utility). Cooler: One stream a process fluid and the other stream a cold utility, such as cooling water or air. .44
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Cont. Heater: One stream a process fluid and the other stream a hot utility, such as stream or hot oil Condenser: One stream a condensing vapor and the other stream a cold utility, such as cooling water or air.
45
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Cont. Chiller: One stream a process fluid being condensed at sub-zero temperature and the other stream a boiling refrigerant or process stream (evidently cryogenic). Vaporizer: One stream a vaporizing liquid and the other a gas or a liquid. Re-boiler: One stream a bottom stream from a distillation column and other a46
RE-BOILER
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COMPONENT OF STHEs : The principal components of an STHE are: Shell and Shell cover Tubes Channel and Channel cover48
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COMPONENT OF STHEs : Tube sheet Baffles Floating head cover Nozzles49
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COMPONENT OF STHEs : The other components are, Tie-rods and spacers, Pass partition plates, Impingement plate,
50
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COMPONENT OF STHEs : Longitudinal baffles, Sealing strips, sliding strips, Supports and foundation51
VARIOUS PARTS OF HEAT EXCHANGER
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VARIOUS PARTS OF HEAT EXCHANGER1.Stationary Head-Channel 2.Stationary Head-Bonnet 3.Stationary Head Flange-channel Or Bonnet 4.Channel Cover 5.Stationary Head Nozzle 6.Stationary Tubesheet 7.Tubes 8.Shell 9.Shell Cover 10.Shell Flange-Stationary Head End 11.Shell Flange-Rear Head End 12.Shell Nozzle 13.Shell Cover Flange 14.Expansion Joint17.Floating Head Cover Flange 18.Floating Head Backing Device 19.Split Shear Ring 20.Slip-On Backing Flang 21.Floating Head Cover 22.Floating Tubesheet Skirt 23.Packing Box 24.Packing 25.Packing Gland 26.Lantern Ring 27.Tierods and Spacers 28.Transverse baffles or Support Plates 29.Impingement Plate 30.Longitudinal Baffle 31.Pass Partition
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SHELL AND SHELL COVER: The shell is cylinder in which tubes are contained and serves to contain the shell side flowing stream and forms the outer casing of the tube bundle. TUBE BUNDLE: The tube bundle is the heart of the shell and tube unit and comprises tubes, tube sheets, baffles, floating head cover, split ring. Tie rods, impingement plate, baffle, longitudinal baffle and sealing/sliding54
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TUBES: Tubes are most vital component of the heat exchangers. Tubes are two types, namely a) plain or bare and b) finned external or internal Plain tubes are most common ones which are generally used in refineries
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Cont. Tubes are usually defined by outer dia (OD) and wall thickness (or BWGBirmingham Wire Gauge). Wall thickness can be either minimum wall (when there is no under-tolerance, but only over tolerance), or average wall thickness (when there is both under tolerance and over tolerance).56
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Cont. The usual practice is to order tubes with minimum wall thickness for carbon steel and low alloy steel tubes and with average wall thickness for non-ferrous and high-alloy steel tubes. Material of construction of tubes arecarbon steel, low and high alloy steels, special stainless steels, Admiralty brass and bronze, alloys of57
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TUBE SHEETS: The ends of the tubes fit into a common sheet and are expanded against or welded to the shell to form a pressure tight seal which separates fluid in the shell and that in the tubes. Tube sheet are two types Fixed/stationary tube sheet A tube sheet fixed or welded to the shell.58
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Welded tube to tube sheet joints are usuallyemployed for severe condition such as high pressure (say, in excess of 80 kg/cm) or when handling toxic or inflammable fluids where leakage is not permitted. Floating tube sheet: A tube sheet which can move to allow for expansion or contraction of the tubes relative to the shell.59
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Tube sheet thickness can vary from 25 mm for low-pressure low shell dia. to 300 mm for high pressure & large shell Depending on the severity of the situation, tubes are either expanded into grooves in the tube sheet or welded to theme to tube sheet
Baffles: It serve to support the tubes as well as to impart a sufficiently shell side velocity to yield a satisfactory heat 60 transfer co-efficient.
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Baffles are held securely in place by a combination of tie rods and spacers. The length of spacers is equal to the baffle spacing. The outside diameter of the baffle has to be less than the inside diameter of the shell to permit insertion of the tube bundle into the shell and removal of the bundle from the shell.61
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ONGITUDINAL BAFFLES: A plate which is placed transversely along the centre line of the shell and is employed to divide the shell into two or more compartments is called longitudinal baffle. A single longitudinal baffle from one tube sheet to just sort of the other tube sheet produce on F shell i.e. a shell with two shell passes.62
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SLIDING AND SEALING STRIPS: A pair of sliding strips is provided at the bottom of floating head tube bundles for their insertion and removal to and from the shell. A sufficient number of sealing strips is required to be inserted in the gap between the shell and outer most tubes in floating head tube bundles to minimize leakage of the shell
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IMPINGEMENT PLATE: The inlet nozzle is provided with a plate which is used to protect the uppermost tubes located just below the shell side inlet nozzle against direct impingement by the shell side fluid is called an impingement plate. CHANNEL, CHANNEL COVER & PASS PARTITION PLATES: Channel is the inlet and outlet chambers for the fluids flowing through the tubes.64
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A channel may either be of a bonnet const. where a dished end is welded to channel barrel or a flanged channel cover. Pass partition plates are the plate in the channel which make the fluid in the tubes flow through one set of tubes and back through another set. They fit tightly into grooves in the tube sheet and channel cover in order to eliminate the possibility of leakage65
PASS PARTITION ARRANGEMENT FOR TUBE PASSESPDEC
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CODES/STANDARDS: API 660 - Shell & tube heat exchangers for general refinery services. ASME Section VIII Pressure Vessels for Shell thickness cal., Welding & Testing requirements. TEMA(Tubular Exchanger67
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TEMA: There are three classes of TEMA; Class-R Refinery Service Class-B Chemical Process service Class-C General service LIMITATION OF TEMA: Inside diameter of shell is 2540 mm A design pressure of 211 kg/cm268
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BASIC FORMULA: The basic formula for heat transfer is, Q = A* U*T Where, Q = Total heat to be transferred, Kcal/hr A = Required effective heat exchanger surface, based on the tube O.D , m2 U= Overall heat transfer coefficient,Kcal/hr-m2-c
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Cont. T = effective mean temperature difference, OC For exchangers where the flow of the hot and cold fluids is true counter or concurrent, T is equal to the log mean temperature difference (LMTD) In most commercial exchangers, the use of shell baffles and multiple tube passes70
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Cont. partially concurrent flow. For this mixed flow T is obtained by applying a correction factor (F) to the calculated LMTD for a counter current flow arrangement i.e. T (effective) = LMTD * F ( F= < 1.0) T - T h c LMTD = Ln ( h / T ) (T c Where,71
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Cont. Where, Th = T1 - t2 Tc = T2 - t1 T1 = Inlet temp. of hot fluid T2 = Outlet temp. of hot fluid t 1 = Inlet temp. of cold fluid t = Outlet temp. of cold fluid72
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Cont. The value of correction factor F is obtained from TEMA chart. F is plotted as a function of P and R . Where and R P = Temp. effectiveness or efficiency of exch. = (t of cold fluid) / (t of hot & cold t1 - 1 t fluidP = inlet temp.)
T1 - t 1
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Cont. Where, R = Heat capacity rate ratio. = wc / Wc
R=
T1 - T 1 t1 t 1 74
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BASIS OF DESIGN PRESSURE: Maximum pump shut of pressure, or 25 psi or 10% greater than the maximum operating pressure in PSIG BASIS OF DESIGN TEMPERATURE: The minimum design temp is normally set a 25oC above the maximum operating temp at the exchanger75
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DESIGN OF STHEs: The design of shell and tube heat exchangers comprises two distinct activities are: Thermal design and Mechanical design76
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Thermal design: In thermal design, the heat exchangers is sized, which means that all the principal construction parameters such as shell type and diameter, number of tubes, tube OD and thickness, tube length, tube pitch, number of tube passes, baffle spacing & cut and nozzles sizes are determined.77
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Basic aims of a thermal designer are: 1.Produce a thermal design that has a low overall cost. Overall cost = initial cost + operating cost Initial cost is evidently the fixed cost or first cost of the heat exchangers Operating cost = pumping cost + maintenance cost + down time cost78
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Cont.: Maintenance cost= periodically cleaning cost + anti - foulant cost + any repair or replace. Cost. 2. Utilize allowable pressure drop as fully as possible. Higher the velocity of the fluid higher will be the heat transfer co-efficient. Higher heat transfer co-efficient will be higher pressure drop.79
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Cont.: Higher heat transfer co-efficient will tend to reduce first cost of the exchangers. Higher pressure drop will tend to increase the operating cost of the exchangers Thus a very important goal for a good thermal design is the best utilization of the allowable pressure drop80
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REQUIRED DATA FOR THERMAL DESIGN : Process dept. have to furnish the following data for thermal design of heat exchangers: Name of the fluids Flow rate of the fluids Inlet & outlet temperature of the fluids
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Cont. Allowable pressure drop Generally 0.5 to 0.7 kg/cm2 per shell for liquid 0.05 to 0.02 kg/cm2 per shell for gases Fouling refers- accumulation and deposition of living organisms and certain non-living materials on the surface Properties of fluids like Specific gravity/82
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Cont. Heat release profile for two phase flow it is a plot of heat duty and weight fraction vapor versus temperature and is an essential part of the process data sheet. Heat exchanged i.e. heat dutyProc ss d ta e a sh e of H 1 f... et E .pd83
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Cont. Selection of heat exchanger type i.e Fixed tube, U-tube or Floating head tube exchangers (i.e AES, BEM )etc. Placement of Fluids Generally low flow rate fluid is placed on the shell side .This facilitates provision of adequate turbulence by increasing number of baffles84
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Cont. Cooling water which is likely to deposit scales is generally placed on tube side for facilitating mechanical cleaning of tubes from inside In general highly befouling fluids that need frequent mechanical cleaning of heat exchangers are usually placed on tube side Highly corrosive fluids are preferably placed on tube side85
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Cont. Fluids with very high operating pressure are preferably placed on tube side Line sizes: Generally line size match with nozzle sizes Preferred tube size: OD: Commonly used OD 19.05/ 25.4 mm Tube thick.: Commonly used thk.2 / 2.5 mm86
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Cont. Maximum shell diameter As per TEMA ID is 2540 mm As per engineering practice, For floating & U-tube exchangers: Shell ID 1400-1500 mm For fixed tube heat exchanger: No limitation87
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Cont. Corrosion allowance Tube: As per TEMA no corrosion allowance is applied in tube Shell: Depends on services and materials of construction. Generally 1.5 to 3 mm is used depending on materials.88
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Cont. Velocity In-general very high velocity lead to erosion. For liquid- minimum recommended velocity in s tube side is 0.9 m/s while maximum is 2.4 m/s. Shell side velocity is from 0.6 t0 1.5 m/s For gases maximum tube side velocity is 35 m/s89
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Cont. Type of shell As per TEMA, there are seven types of shells like E, F, G, H, J, K & X. Tube lay out pattern There are 4 types of tube lay out pattern.90
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Triangular- Not Used when mechanically cleaning is required. Rotated Triangular- Not Used when mechanically cleaning is required
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Square- When mechanically cleaning is required Rotated squarecleaning is required When mechanically
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Tube Pitch; center to center distance between two adjacent tubes.For triangular & rotated triangular pattern tube pitch is 1.25 times the tube OD
For square or rotated square pattern tube pitch is generally (OD+6mm)
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SELECTION OF HEAT EXC.TYPE BASIS ON SERVICES
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Final decision on exchanger type depends on many factors but the table given below is only for guide Shell side fluid Tube side fluid Type of exchanger lineClean Yes Yes Dirty Yes Clean Yes Yes Dirty Yes Fixed tube sheet or U-tube with triangular pitch Fixed tube sheet or floating head with triangular pitch U-tube or floating head with square pitch
-
Yes
-
Yes
Floating head with square pitch
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THERMAL DESIGN OF HEAT EXCHANGERS IS DONE BY HTRI (Heat Transfer Research Institute) Soft ware, USA
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THERMAL DATA SHEET OF HEAT EXCHANGER: Heat exchanger thermal specification sheet is divided into three parts, General information of exchangers Performance of exchangers Construction of exchangersTHERMAL DATA SHEET.pdf96
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MECHANICAL DESIGN: Detailed calculations are carried out to determine the dimensions of various components such as tube sheets,girth flanges, shell , shell barrel, channel, channel barrel,Baffle plate, floating head dish, etc and a complete bill of materials and engineering drawings such as bundles assembly and setting plan drawings are generated.97
Baffles: Generally there are two types of baffles Plate type - Single segmental - Double segmental - Triple segmental
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PLATE TYPE BAFFLES:
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ROD TYPE BAFFLEEntire heat transfer area is effective Tube bundle is vibration free No stagnation of flow, uniform flow Pressure drop minimum
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ROD TYPE BAFFLE:
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BAFFLE SPACING: Center to center line distance between adjacent baffles is called baffle spacing Minimum spacing as per TEMA is one fifth of the shell ID or 51 mm whichever is greater.102
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BAFFLE SPACING: For example if shell inside diameter = 1000 m Then 1/5th = 1000/5 = 200 mm So spacing should be 200 mm Maximum spacing is usually the shell ID
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BAFFLE CUT: It is the segment opening heights expressed as a percentage of the shell inside diameter . Baffle cuts are : Horizontal- This is used for single pass shell for minimizing the accumulation of deposit at the bottom.
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BAFFLE CUT: Vertical - This is used for two pass shell for ease of fabrication and bundle assembly, as well as for condenser.
Recommended baffle cut is from 20% to 35%
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BAFFLE PLATE THICKNESS :
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Baffle or support plate thickness should be as per below table (R-4.41 of TEMA)Shell ID Plate thickness Unsupported tube length between central baffles 610 mm & under152 356 381 - 711 735 - 965 991 - 1524 1549 - 2540 3.2 4.8 6.4 6.4 9.5
Over 610 - Over 914 - Over 1219 - Over 914 mm 1219 mm 1524mm 1525mm4.8 6.4 7.5 9.5 12.7 6.4 9.5 9.5 12.7 15.9 9.5 9.5 12.7 15.9 19.1 9.5 12.7 15.9 15.9 19.1
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TIE ROD AND SPACERS:
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Tie rod and spacers shall be provided to retain all baffles and tube support plates securely in position. Number and size of the tie rods will be as per below table (R-4.71 of TEMA)Nominal shell diameter in mm 152 - 381 406 686 711 838 864 1219 1245 1524 1549 - 2540 Tie rod diameter in mm 9.5 9.5 12.7 12.7 12.7 15.9 Minimum number of tie rod 4 6 6 8 10 12107
Material Identification chart:Description of parts Shell Shell cover barrel Shell cover bonnet Channel Channel cover Tubes Tubes sheet Baffles Floating Head Dish Girth Flanges Carbon steel SA516Gr60/70 SA516Gr60/70 SA516Gr60/70 SA516Gr60/70 SA105 SA179 SA266Gr.2 SA516Gr60/70 SA266Gr.2 SA266Gr.2 Alloy steel SA387GR5CL2 SA387GR5CL2 SA387GR5CL2 SA387GR5CL2 SA182GrF5 SA213GrT5 SA336GrF5 SA387 Gr5CL2 SA336GrF5 SA336GrF5 Stainless Steel SA240Gr316 SA240Gr316 SA240Gr316 SA240Gr316 SA182Gr316 SA213Gr316 SA240Gr316 SA240Gr316 SA336Gr316 SA336Gr316
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Material Identification chart:Description of parts Nozzles Neck Nozzles Flanges PAD Backing Ring Tie Rods Partition Plate Impingement plate Sealing strips Spacers Saddle plate Carbon steel SA106GrB SA105 SA516Gr60/70 SA105 SA516Gr60/70 SA516Gr60/70 SA516Gr60/70 SA516Gr60/70 SA179 SA516Gr60/70 Alloy steel SA335GrP5 SA182GrF5 SA387GR5CL2 SA336GrF5 SA387GR5CL2 SA387GR5CL2 SA387GR5CL2 SA387GR5CL2 SA213GrT5 SA387GR5CL2 Stainless Steel SA312Gr316 SA182Gr316 SA240Gr316 SA336Gr316 SA240Gr316 SA240Gr316 SA240Gr316 SA240Gr316 SA213Gr316 SA240Gr311
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MECHANICAL DATA SHEET OF EXCHANGER: This is required for procurement of heat exchangers.Mechanical Data sheet .pdf
110
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DESIGN SOFTWARE: PV ELITE and Microprotol software are being used worldwide Microprotol By EU Research, France PV- Elite by COADE taken over by Intergraph, USA111
MANUFACTURING FEATURES
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DRAWINGS AND ASME CODE DATA REPORT: Drawings for approval and change The manufacturer shall submit for purchasers approval three(3) prints of an outline drawing showing nozzle sizes and locations, overall dimensions, support and weight. It is anticipated that a reasonable number of minor drawing changes may112
MANUFACTURING FEATURES
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Cont. Any changes may cause additional expense chargeable to the purchaser. Purchasers approval of drawings does not relieve the manufacturer of resposibility for compliance with the standard and applicable ASME code requirements. The manufacturer shall not make any changes on the approved drawings without express agreement of the
113
MANUFACTURING FEATURES
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Cont. Any changes may cause additional expense chargeable to the purchaser. Purchasers approval of drawings does not relieve the manufacturer of responsibility for compliance with the standard and applicable ASME code requirements. The manufacturer shall not make any changes on the approved drawings without express agreement of the
114
MANUFACTURING FEATURES
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Cont. Shop detail drawings are for internal use by the fabricator, it may be furnished to the purchaser upon request. Drawings for record After approval of drawings manufacturer furnished 3 set of drawings along with all documents to the purchaser115
MANUFACTURING FEATURES
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Proprietary rights to drawings The drawings and the design indicated by the manufacturer are to be considered the property of the manufacturer and are not to be used or reproduced without his permission, except by the purchaser for his own internal use. ASME code data reports After completion of fabrication and inspection of ASME code stamped exchangers, the manufa. shall furnish 3116
MANUFACTURING FEATURESINSPECTION: There are two yepes of inspection: Manufacturers Inspection Purchasers Inspection Manufacturers Inspection Inspection and testing of units will be provided by the manufacturer unless otherwise specified.
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117
MANUFACTURING FEATURES The manufacturer shall carry out the inspection required by the ASME code and also inspection by state and local codes .
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Purchasers Inspection The purchaser shall have the right to make inspection during fabrication and to witness any test. Inspection by the purshaser shall not118
MANUFACTURING FEATURES
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PREPARATION FOR SHIPMENT: Cleaning Internal and external surfaces are to be free from loose scale and other foreign material that is readily removable by hand or power brushing Draining Water, oil or other liquids used for cleaning or hydro-static testing are to be119
MANUFACTURING FEATURES Flange protection All exposed machined contact surfaces shall be coated with a removable rust preventative. All threaded connections are to be suitably plugged.
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Damage protection The exchangers and any spare parts are to be suitably protected to prevent120
MANUFACTURING FEATURESGUARANTEES: It may be given on the basis of Performance and Defective parts Performance Guarantee The manufacturer shall guarantee thermal performance and mechanical design of a heat exchanger, when operated at the design conditions specified by the purchaser in his order.
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MANUFACTURING FEATURESCont.
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This guarantee shall extend for a period of twelve months after shipping date. The thermal guarantee shall not be applicable to exchangers where the thermal perfomance rating was made by the purhaser.122
MANUFACTURING FEATURES Defective parts Guarantee
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The manufacturer shall repair or replace any parts proven defective within the guarantee period. Finished materials and accessories purchased from other manufacturers, including tubes are warranted only to the extent of the original manufacturers warranty to the heat exchanger.123
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MANUFACTURES OF HEAT EXCHANGER: M/s Aero-therm Products M/s Hindustan Radiators M/s Unique Chemo-plant Equipments M/s Larsen & Toubro124
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MANUFACTURES OF HEAT EXCHANGER: M/s Hindustan Dorr Oliver Ltd M/s Godrej M/s Precision Engineering. M/s Universal Heat Exchangers125
PDEC
MAINT. OF HEAT EXCHANGERS
126
ROUTINE MAINTENANCE
PDEC
OPERATIONAL PROBLEMS Decline in heat transfer efficiency / high pressure drop Scaling, fouling, choking, etc., Internal Leak Causing contamination between shell and tube fluids
127
ROUTINE MAINTENANCEOPERATIONAL PROBLEMS Gasket Leaks Due to thermal shock during startup, shutdowns & Upsets Tube Leaks Tube failure due to fatigue, ageing & corrosion BLINDING THE EQUIPMENTS
PDEC
128
PASSIVATION
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Why ? (During a shutdown, in the presence of air and liquid water, often dew point water, the sulfides convert to polythionic acid which causes inter-granular Stress Corrosion Cracking to Austenitic steels) Materials prone for SCC (Austenitic SS tube bundles - SS 304, SS310, SS316, SS321, SS347)129
PASSIVATIO N When ? Before Opening of the equipments
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Solution Soaked with a solution of DM Water, Sodium Carbonate (2%) and Sodium Nitrate (0.5%) for about 8 hours.
130
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Opening the covers of heat exchangers Removing of bundle Bundle Extractor or Puller
131
EXCHANGER CLEANING Chemical Cleaning Shell - Fixed Tube Sheet Bundle Vacuum Condensers, Ejector Condensers, Reboilers 0.5% concentration HCl with inhibitor circulation for 8 hours Hot water wash Branded chemicals Online by wash water circulation
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132
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Kero -bath soaking Crude vacuum, Asphalt services Hydroblasting (For Tube exteriors) Water jet at a pressure of 300 - 600 Kg/Sq.cm (Up to 35000 psi / 2500 bar)
133
Hydro-blasting (For Tube exteriors)
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Before Cleaning
After Cleaning
134
Hydro-lancing (For Tube interiors)
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Manual Operation
Power Lancing135
Hydro-lancing (For Tube interiors)
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Before Cleaning
After cleaning136
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Gasket Replacement A gasket is a compressible material, or combination of materials, which when clamped between two stationary members prevents the passage of the media across those members. Gasket Selection Tem. of the media to be contained, Corrosive nature of the application and Criticality of the137
PDEC
GASKET CLASSIFICATION CAF (Compressed asbestos fiber) 250 deg. C, 30 bar, Water, steam and for non-critical applications
138
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GASKET CLASSIFICATION IJA (Iron Jacketed Asbestos) High Temperature applications Sheet Metal - SS, Brass, Monel , Al, In-conel Filler - Asbestos, PTEF, Grafoil
139
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GASKET CLASSIFICATION Spiral Wound Gasket (SPWD)(SPWD) with Asbestos filled & Inner Ring (13mm) & Outer Nose (4 mm width) 260 650 C Winding - SS 410, 304, 316, Monel, Inconel Filler - CAF(360oC), PTFE(260oC), Graphite(550oC), Ceramic(650oC)140
PDEC
TUBE BUNDLE RETUBING More number of tubes plugged Not possible to clear the tubes Scaling & poor heat transfer After average life of the bundle Frequent failures
141
PDEC
TUBE BUNDLE RETUBING Full or Partial Where At Bundle Shop or at Position
142
PDEC
THANK YOU
143