Instruction Manual Plate & Shell Heat Exchanger AlfaDisc 50, … · 2019. 9. 23. · Except for...

EN

Instruction ManualPlate & Shell Heat Exchanger

AlfaDisc 50, 100, 150

Part number xxxxxxx0702

Table of contents English

Plate & Shell Heat Exchanger EN

EN

Table of contents

Description ....................................................................................... 1Definitions .................................................................................. 1Main components ..................................................................... 2Core assembly/disassembly ...................................................... 3Name plate ................................................................................ 4Function .................................................................................... 5Plate pack .................................................................................. 6

Installation ........................................................................................ 7Requirements ........................................................................... 7Installation in general................................................................. 7Filter........................................................................................... 8Installation as evaporator........................................................... 8Installation, welding aspects ...................................................... 8Lifting ........................................................................................ 9

Operation ........................................................................................ 10Start-up ................................................................................... 10Unit in operation ...................................................................... 11Shut-down ............................................................................... 12

Maintenance ................................................................................... 13General guidelines regarding maintenance ............................. 13Cleaning-In-Place (CIP) .......................................................... 14

Fault-tracing ................................................................................... 15Pressure drop problems ......................................................... 15Heat transfer problems ............................................................ 16

Except for this Instruction Manual, the following documents are also included in this shipment:

– Welded Plate Heat Exchanger drawings

– Declaration of Conformity or U-stamp

– Hydrotest certificate

– Material certificate.

How to contact Alfa Laval:

Contact details for all countries are continually updated on our website.

Please visit www.alfalaval.com and contact your local Alfa Laval Representative.

English Notes

Plate & Shell Heat ExchangerEN

EN

Notes

Description English

Plate & Shell Heat Exchanger 1EN

EN

Description

Definitions

All-welded plate heat exchanger

This all-welded unit is designed to withstand extreme pressure and high temperatures thus providing the thermal efficiency and compactness of a plate and frame unit under conditions that would normally call for a shell and tube unit.

Cassette Two plates welded together at pipe holes and outer rims forming media channels between the plates.

Core One or more plate packs are welded together with end plates and pipes and are either installed as a removable unit into a shell or welded into a casing that must not be opened.

Cover plates Cover plates are mounted to the front and rear ends of the cylindrical shell.

End plate End plates are welded to top and bottom of a plate pack thus forming a core.

Heat transfer area The area of the plate, which is in contact with both fluids.

Plate A sheet of material pressed into a corrugated pattern.

Plate pack An assembly of cassettes welded together to an unit having internal channels in which two or more fluids can be handled.

Port Inlet or outlet opening in the front and rear cover plates. The number of ports depend on how many media the AlfaDisc Plate & Shell Heat Exchanger handles.

Removable core The core with its end plates, plate packs and pipes is welded to a front cover plate which is inserted in the cylindrical casing of the AlfaDisc Plate & Shell Heat Exchanger and fastened with bolts.

Shell A cylindrical assembly with front and rear cover plates provides the structural support and the pressure containment of the AlfaDisc Plate & Shell Heat Exchanger.

Total heat transfer area The total surface area of all the bonded plates, which are in contact with both fluids.

English Description

2 Plate & Shell Heat ExchangerEN

EN

Main components

Stand

ConnectionEquipped with different connection types, permitting the media to enter into the heat exchanger.

Lifting lugFor correct and safe lift during mounting of the removable core.

Cover platesFront and rear cover plates to protect the core.

Bolts

Lifting lugsFor correct and safe lifts during transportation and installation.

ShellCylindrical casing to pro-tect the removable core.

Description English


EN

Core assembly/disassembly

Port holes of two discs are seam welded to form a cassette.

A number of cassettes are welded together to form a plate pack.

Assembly, unremovable core

Plate packs are welded to end plates forming the so called core.

The core is then mounted into a shell with front and rear cover plates (parts marked blue in the figure to the right). The front cover plate of a removable core is fixed to the shell with bolts, whereas the front cover plate of the unremovable core is welded to the shell.

These core assemblies are made in the vertical posi-tion. At installation the core is tilted into the horizontal position.

At disassembly of a heat exchanger with a remova-ble core, the core is pulled out of its shell horizontally by means of straps, see chapter Lifting.

Assembly, removable core

Port hole

Front cover plate

End plate

Plate pack

Rear cover plate

Pipes

Cassette

Pipe

Shell

Front cover plate

End plate

Plate pack

Rear cover plate

Connec-tions

Bolts

Cassette

Lug

Shell

English Description


EN

Name plateOn the name plate the type of unit, manufacturing number and manufacturing year can be found. Pressure vessel details in accordance with the ap-plicable pressure vessel code are also stated. The name plate is fixed on the front side between the connections or on the back side.

Warning!For each unit, the mechanical design pressures and temperatures are marked on the name plate. These must not be exceeded.

The nameplate shows:1. Space for logotype.2. Manufacturer name.3. AlfaDisc type.4. Serial number.5. Side.6. Volume.7. Design temperature.8. Design pressure.9. Test pressure.

10. Max. allowed operating temperature.11. Customer unique information.12. Weight kg (empty).13. Test pressure, date.14. Year.15. Fluid group.16. Plate side.17. Shell side.

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Description English


EN

Function

The AlfaDisc Plate & Shell Heat Exchanger provides the thermal efficiency and compactness of a plate and frame unit under conditions that would normally call for a shell and tube unit.

The AlfaDisc is designed for use with liquids, gases and two-phase mixtures at pressures up to 72 bar and at temperatures up to 540 °C. The Plate & Shell unit works well with aggressive media, such as or-ganic solvents, steam heaters and interchangers that are beyond the capability of a gasketed unit.

The unit features a plate side and a shell side, which offer high pressure ratings. It has alternating chan-nels for hot and cold media, and can offer counter-current or co-current flow.

Nozzle sizes up to DN 400 can be accommodated on the shell side of the exchanger, offering higher steam and liquid flow rates. Nozzles on the plate side can be up to DN 150.

The AlfaDisc Plate & Shell Heat Exchange can be fabricated from dissimilar metals when only one side will be exposed to corrosive conditions.

By-pass restriction diverters

Turning Plate Portfor multi-pass designs.

Shell divider

Flow principle of a multi-pass AlfaDisc

The plate heat exchanger is typically used for heat-ing or cooling media with low to medium viscosity. A specific heat exchanger is dimensioned for a specific duty, set out in the product documentation, and should not be used in any other way without consulting the supplier.

Flow principle of a single-pass AlfaDisc

English Description


EN

Plate pack

The AlfaDisc Plate & Shell Heat Exchanger con-sists of a pack of corrugated metal discs with welded ports for the passage of the two fluids be-tween which heat transfer will take place. The me-dia are led into the plate pack through its portholes and are distributed into the passages between the welded, corrugated plates.

The heating surface consists of thin corrugated discs stacked on top of each other as shown in the figure below. In the welding process channels are formed between the plates.

The welded ports form cylinders through which the two media flow, either in counter-current or co-current flow. One or a number of plate packs are welded to end plates into a unit with top and bot-tom covers. This unit constitutes a core construc-tion which is removable.

A plate pack is highly resistant to thermal expan-sion because of the “accordion” like core con-struction.

Honeycomb patternMedia flow directions between the corrugated discs in a plate pack.

Welded plate pack for media flow in alternate channels.

Media flowbetween two discs forming a cassette.

Installation English


EN

InstallationRequirements

Installation in generalThe installation must be provided with equipment that protects the heat exchanger against pressures and temperatures outside the approved minimum and maximum values shown on the name plate.

For best possible heat transfer performance, the AlfaDisc Plate & Shell Heat Exchanger should be connected so that the media flow through the core passes in opposite directions (in counter-flow). Take into account the risk of fire during the installation work, i.e. bear in mind the distance to flammable substances.

Warning!The heat exchanger must be installed and operated in such a manner that no risk of injury to personnel and damage to proper-ty will be incurred.

Note!Unless otherwise specified, product data for normal refrigerants, i.e. HFC and HCFC, are applicable to refrigeration applications.

The manufacturer must be specifically con-sulted before the heat exchanger is used for flammable, toxic or dangerous liquids (e.g. hydrocarbons). The use must follow the relevant safety rules for handling such liquids.

Warning!Safety valves should be installed according to pressure vessel regulations.

Note!Before connecting any piping, make sure all foreign objects have been flushed out of the system.

FoundationInstall on a flat foun-dation giving enough support to the unit.

Protection against pipe forcesFit the pipes so that no tension is transferred to the heat exchanger.

Filter

Tightening bolts

Gasket

Port strainer

Lifting lugsFor correct and safe lifts during transportation and installation

English Installation


EN

Filter

To avoid unwanted particles during start-up, in-stall a filter on the inlet connections.

Installation as evaporatorFor refrigeration applications the connections of an evaporator may be either on the front or on the rear. In evaporator applications and in applica-tions in which a phase change of media occurs, the heat exchanger should be installed horizontal-ly. • Use an anti-freeze thermostat and flow moni-

tor to ensure a constant water flow before, dur-ing and after the compressor has been running.

• Avoid “pump-down”, i.e. emptying the evapo-rator by running the compressor after shut-down until a preset refrigerant pressure is reached. The temperature could then drop below the brine freezing point, which could damage the evaporator.

• Use a flow switch and a low-pressure switch..

Installation, welding aspectsFor installation of AlfaDisc equipped with welded connections, TIG or MIG welding method must be used for installation of the heat exchanger to min-imize heat impact of the heat exchanger.

Note!To avoid damage due to freezing, the medium used must include an anti-freeze agent at operating conditions be-low 5 °C and/or when the evaporating temperature is below 1 °C.

Installation English


EN

Lifting

Lifting during installation Lifting during mounting/dismounting of the removable core

Warning!Never lift by the connections or the studs around them. Straps should be used when lifting. Place straps according to picture.

English Operation


EN

OperationStart-up Check that the valve is closed between the

pump and the unit controlling the system flow rate.

If there is a valve at the exit make sure that it is fully open.

Open the vent and start the pump.

Open the valve slowly.

When all air is expelled, close the vent.

Repeat steps 1–5 for the second media.

Note!If several pumps are included in the system, make sure you know which one should be activated first.

Note!Adjustments of flow rates should be made slowly in order to avoid the risk of water hammer.

Water hammer is a short-lasting pres-sure peak that can appear during start-up or shut-down of a system, causing liq-uids to travel along a pipe as a wave at the speed of sound. This can cause con-siderable damage to the equipment.

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Shell side inlet

Shell side outlet

Front side inlet

Front side outlet

Valve

Operation English


EN

Unit in operation

During operation, check thatmedia temperatures and pressures are within the limits stated on the name plate

no leakages appear due to faulty tightening of the connections.

Protection against freezingBear in mind the risk of freezing at low temperatures. Plate & Shell Heat Exchangers that are not in opera-tion should be emptied and blown dry whenever there is risk of freezing.

Protection against cloggingUse a filter as protection against the possible occur-rence of foreign particles. If you have any doubt con-cerning the maximum particle size, consult your nearest representative of the supplier or look under Product information at the supplier's Internet site.

Back flushing When fibres or large particles are present, back flushing of the unit often proves to be efficient. This is accomplished by either of the following methods:• Flush the unit with clean water in reverse flow

to the normal operating direction.

• Arrange piping and valves so the unit may be operated in reverse flow mode on the product side for fixed periods of time.

StrainersThe use of strainers is recommended in supply lines ahead of the exchanger when the stream contains significant solids or fibres. This will reduce the need of back flushing.

If any of the media contains particles larger than 1 mm, it is recommended that a strainer with a size of the hole of 1.5 mm be installed before the ex-changer. The particles could otherwise block the channels, causing bad performance, increase pres-sure drop and risk of freezing.

Note!Adjustments of flow rates should be made slowly in order to protect the system against sudden and extreme variations of tempera-ture and pressure.

Note!To avoid damage due to freezing, the medi-um used must include an anti-freeze agent at operating conditions below its freezing point.

Inlet

Outlet

Washings

To EffluentTreatment

Shell SideInlet

Shell SideOutlet

AutomaticBackflush

Valve

BackflushingCycle

FromProcess

ToProcess

PLC

English Operation


EN

Protection against thermal or/and pressure fatigueSudden temperature and pressure changes could cause fatigue damage to the heat exchanger. Therefore, following must be taken into consider-ation to ensure that the heat exchanger operates satisfactorily. Locate the temperature sensor as close as possible to the outlet from the heat ex-changer.• Choose valves and regulation equipment

which give stable temperatures/pressures for the heat exchanger.

• To avoid water hammer, quick-closing valves must not be used, e.g. on/off valves.

In automated installations, the stopping and start-ing of pumps and actuation of valves should be programmed so that the resulting amplitude and frequency of the pressure variation will be as low as possible.

Protection against corrosionAll components in contact with media are manu-factured in stainless steel grade AISI 316L.

InsulationHeating and cooling insulations are available as accessories.

Shut-down

Slowly reduce the flow rate in order to avoid water hammer.

When the valve is closed, stop the pump.

Repeat steps 1–2 for the other medium/media.

If the plate heat exchanger is shut down for a longer period, it should be drained.

Draining should also be done if the pro-cess is shut down and the ambient temper-ature is below freezing temperature of the media.

Depending on the media processed, it is also recommended to rinse and dry the heat exchanger and its connections.

Also see chapter Maintenance, CIP.

Note!If several pumps are included in the sys-tem, make sure you know which one should be stopped first.

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Maintenance English


EN

Maintenance

General guidelines regarding maintenance

Plate Sheet material Also stainless steel can corrode. Chlorine ions are hazardous.

Avoid cooling brines containing chloride salts such as NaCI and, most harmful, CaCI2.

Chlorine as a growth inhibitor

In every case where chlorination of AlfaDisc Shell & Plate Heat Exchanger cannot be avoided, your local representative must be consulted.

Note!Rinse well!

Note!Under no circumstances should Hydrochlo-ric acid be used with stainless steel plates.

Water of more than 300 ppm Cl ions may not be used for preparation of cleaning solutions.

Note!Chlorine, commonly used as growth inhibi-tor in cooling water systems, reduces the corrosion resistance of stainless steels.

Chlorine weakens the protection layer of these steels making them more susceptible to corrosion attacks than they otherwise should be. It is a matter of time of exposure and concentration.

English Maintenance


EN

Cleaning-In-Place (CIP)

Cleaning-In-Place is the preferred cleaning meth-od to maintain a high level of performance when especially corrosive liquids are processed in a welded plate heat exchanger. Install drain piping to avoid corrosion of the plates due to residual liq-uids left in the unit after an operation cycle.

CIP performs:• cleaning of fouling and de-scaling of lime

deposits

• passivation of cleaned surfaces to reduce susceptibility to corrosion

• neutralization of cleaning liquids before draining.

To prepare the exchanger for cleaning, follow the procedures listed below:1. Drain both sides of the unit. If it is not possible

to drain, force liquids out of the unit with flush water.

2. Flush the unit on both sides with warm water at approximately 50 °C until the effluent water is clear and free of the process fluid.

3. Drain the flush water from the unit and connect the CIP pump.

4. Follow the instructions of the CIP equipment.5. Flush thoroughly with clean water after CIP

cleaning.

The following CIP models can be used: CIP200L, CIP400L and CIP800L.

Cleaning liquid Description

AlfaCaus A strong alkaline liquid, for removing paint, fat, oil and biological deposits.

AlfaPhos An acid cleaning liquid for removing metallic oxides, rust, lime and other inorganic scale. Includes an inhibitor for passivation.

AlfaNeutra A strong alkaline liquid for neutralization of AlfaPhos before drainage.

Kalklöser P An acidic cleaning powder with a corrosion inhibitor particularly effective for removing of calcium carbonate and other inorganic scale.

Neutra P An alkaline powder for neutralization of used Kalklöser P prior to disposal.

AlfaAdd A neutral cleaning strengthener to be used with AlfaPhos, AlfaCaus and Kalklöser P. Provides better cleaning results on oily, fatty surfaces and where biological growth occurs. AlfaAdd also reduces any foaming.

Alpacon Descalant An acidic, water based, non-hazardous cleaning agent designed for removal of scale, magnetite, algae, humus, mussels, shellfish, lime and rust. Containing BIOGEN ACTIVE, a biological mixture made from renew-able materials, as an active ingredient.

Alpacon Degreaser A neutral degreaser to be used with Alpacon Descalant. Effectively removes oil, fat or grease layers, but also reduces foaming. Containing BIOGEN ACTIVE, a biological mixture made from renewable materials, as an active ingredient.

Fault-tracing English


EN

Fault-tracing

Pressure drop problems

The pressure drop has increased.

Action Result Correction

1 Check that all valves are open including non-return valves.

• Measure the pressure just before and just after the heat exchanger, and the flow rate. For viscous media a membrane manometer with a diameter of at least 30 mm should be used.

• Measure or estimate the flow rate if possible. A bucket and a watch showing seconds may be sufficient for small flow rates. For larger flow rates, some type of flowmeter is required.

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2 Compare the pressure drop observed with the one specified for the actual flow rate (see data printout). Is the pressure drop higher than specified?

YES Check the temperature program, see step 3.

NO If the pressure drop is corresponding to the specifications, there is no need for action.If the pressure drop is lower than speci-fied, the pump capacity is probably too small or the observation may be wrong. See pump instruction manual.

3 Check the thermometer readings. Do the readings correspond to those specified?

YES The heat transfer surface is probably clean enough, but the inlet to the heat exchanger may be clogged by some objects. Check the port area.

NO Heat transfer is obviously dropping below specifications, because of deposits on the heat transfer surface, which at the same time also increases the pressure drop, since the passage becomes narrower.If a Cleaning-In-Place (CIP) system is available, follow the instructions and use it to wash out the deposits.

English Fault-tracing


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Heat transfer problems

The heat transfer capacity is dropping.

Action Result Correction

Measure temperatures at inlets and outlets. Also measure flow rates on both media, if possible. At least on one of the media, both temperatures and the flow rate must be measured.• Check to see if the transferred amount of heat

energy corresponds to the specifications.• If great precision is important, it will be neces-

sary to use laboratory thermometers with an accuracy of 0.1 °C, and also to use the best equipment available for flow measurement.

Has the heat transfer capacity of the unit dropped below specified values?

YES Clean the heat transfer surface. Use the Cleaning-In-Place (CIP) system.

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Instruction Manual Plate & Shell Heat Exchanger AlfaDisc 50, … · 2019. 9. 23. · Except for...

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Transcript of Instruction Manual Plate & Shell Heat Exchanger AlfaDisc 50, … · 2019. 9. 23. · Except for...