Classification of Heat Exchangers

Classification of Heat Exchangers

Classification of Heat Exchangers

Heat exchangers are the devices that are used to transfer heat from one fluid to other fluid. Many heat exchangers are been used by us in our daily lives that include condensers and evaporators that are used in air conditioning units and refrigerators.

Boilers and condensers are included in the large industrial heat exchangers in thermal power plants. The radiators and oil coolers are the form of heat exchangers in the vehicles. These heat exchangers are most abundant in all process industries and chemical industries. There are wide varieties of heat exchangers that are used for diverse purposes where the construction also differs widely. The heat exchangers can be classified into different types based on few fundamental concepts. Most frequent types of heat exchangers are used for the analysis and the design methodologies.

The heat exchanger classification is based on the devices basic operation, construction and the type of flow and their arrangements. The heat exchangers are classified as:

  • Recuperators and Regenerators
  • The direct contact transfer and indirect contact transfer processes.
  • Based on geometry as tubes, plates and extended surfaces.
  • The heat transfer mechanisms as single phase and two phase flows.
  • Based on the flow arrangement as parallel flow, counter flow and cross flow.

This is used to recover the waste steam discharge from the industrial applications.

Applications:

  • Counter flow heat exchangers have larger LMTD value and also greater potential recovery. This permits even a smaller area of heat exchange. This will refer to a less expensive heat exchange equipment of the given application.
  • In parallel flow heat exchangers the initial heating rate is very high and this advantage is used where the tube walls are to be developed with their temperature.
  • The rapid initial heating will help to decrease the fluid viscosity that in turn reduces the pumping requirement which reduces the overall cost of the application.

Contherm Scraped Surface Heat Exchangers

Contherm Scraped Surface Heat Exchangers

Contherm Scraped Surface Heat Exchangers

The Contherm scraped-surface heat exchangers are designed for heating and cooling operations in the continuous and semi-continuous processing of many food, health and beauty aid products.

Many prepared food products would quickly foul normal types of heat exchangers, because they’re viscous or sticky, contain particles or alter state when heated.

The new generation of Contherm scraped-surface heat exchangers from Alfa Laval is updated with four new performance enhancements that extend the capabilities of the Contherm range. This means enhanced food safety initiatives, even more gentle treatment of the product and improved resistance to wear and chemical corrosion. An upgrading service named, ConthermFlex, is also available. This gives customers with old scraped surface technology an opportunity to upgrade their equipment.

  • new blade materials with improved physical properties compared to traditional blades. These include a unique detectable polymer that enhances food safety and food security initiatives.
  • a new three-inch tangential head, designed specifically for sanitary and food-processing applications, improves product quality by treating it more gently. It is available as an option for new Contherm heat exchangers or as a retrofit.
  • the new Alfaloy cylinder coating is a thin diamond-impregnated material that offers improved resistance to wear and chemical corrosion. Alfaloy is a cost-effective, FDA-compliant material that extends the service life of the Contherm’s other components.

Convap evaporation module : –

The Contherm SSHE can be modified to form the Convap evaporator, which is particularly suited to concentrating viscous products. The system normally operates under vacuum. The entrainment separator connected to the SSHE by means of a specially designed vapor head allows the separation of the concentrate from the vapor phase.

Air Cooled Condensers

Air Cooled Condensers

Air Cooled Condensers

Overview for Air Cooled Condensers : –

Air Cooled Condensers directly condense exhaust steam from the steam turbine without water consumption. They are frequently used in electrical power plants and waste to energy plants of all sizes.

Air Cooled Condensers for Features : –

An Air Cooled Condenser (ACC) is a direct dry cooling system where the steam is condensed inside air-cooled finned tubes. Since there is no intermediate surface condenser like Indirect Dry Cooling, the overall performance is better.

The SPX Dry Cooling Air Cooled Condenser features long-term mechanical and thermal integrity, excellent corrosion and freeze resistance, low fan power consumption, reliable operation and low maintenance.

An Air Cooled Condenser (ACC) is made of modules arranged in parallel rows. Each module contains a number of fin tube bundles. An axial flow, forced-draft fan located in each module forces the cooling air across the heat exchange area of the fin tubes.

The typical scope for an ACC installation includes the supporting structure, the steam ducting from the steam turbine interface, auxiliaries such as the condensate and drain pumps, condensate and duct drain tanks, the air evacuation units and related piping works and instrumentation.

There are good reasons for purging air from your refrigeration system, operating efficiency being the main one; increased equipment lifespan is another. It’s important, however, that correct purging procedures are used.

This article will examine why air should be purged, and how it should be done.

Air can enter any refrigeration system :-

  • By leaking through condenser seals and valve packings when suction pressure is below atmospheric conditions;
  • When the system is open for repairs, coil cleaning, equipment additions, etc.;
  • When charging by refrigerant trucks;
  • When adding oil;
  • By the breakdown of refrigerant or lubricating oil
  • From impurities in the refrigerant.To determine the amount of air in a refrigeration system, check the condenser pressure and temperature of the refrigerant leaving the condenser against the data in a temperature-pressure chart. If, for example, your ammonia temperature is 85 degrees F, the theoretical condenser pressure should be 151.8 psig.

Cooling Tower Hub with Fun

Cooling towers fan

Cooling Tower Hub with Fun

Our cooling towers are fitted with FRP Axial Flow Fans with Aerodynamic efficiency and significant saving in higher operating cost.

Fan hub assembly is simply designed for easy installation and minimum maintenance. It is dynamically balanced and made of stainless steel plates, aluminum clamp blocks, cast iron bush and all hardware in stainless steel for resistance against corrosion.

Fan Hub assemblies are dynamically balanced on Dynamic Balancing Machines and total Fan Blade assemblies are balanced on specially designed rig for vibration free continuous operation.

Fans are directly driven by electric motors in small models and coupled through gearbox in larger models subject to the tip speed of the fan.

A new generation, state of the art cooling tower fans, the energy economy concept, which means money saving concept. Built with uncompromising international quality standards. Paltech fans are a combination of performance, strength, endurance & reliability unmatched by anyone else.

With our expertise in the axial fan blades design  uses the most efficient aerodynamic profile for the blades designed we accept the challenge to prove power saving not only over metallic cooling tower fans but also against other FRP cooling tower fans.

Design : –

Paltech FRP fan blades have been specially designed aerodynamically for cooling towers.The aerofoil design has been obtained from . Flow characteristic of the fan outlet ensures an optimum distribution of air across the cooling tower, giving an added benefit to the system.

Power Saving : –

Paltech FRP fans are most efficient, consumes upto 30% less power than conventional aluminium alloy / FRP blades. Thus saving in operational cost is enormous.

Light Touch & Strong : –

Due to considerably lower mass of FRP blades, drives & support frames can be made smaller & hence cheaper. FRP blades are made by specially adopted technique. These are hollow & light but are extremely fatigue resistant, tough & strong.

Direct contact heat exchangers Gas–Liquid Exchangers

Direct contact heat exchangers Gas–Liquid Exchangers

Direct contact heat exchangers Gas–Liquid Exchangers

Mechanical Compression  :-
During the compression cycle, the refrigerant passes through four major components within the chiller: the evaporator, the compressor, the condenser, and a flow-metering device such as an expansion valve. The evaporator is the low-temperature (cooling) side of the system and the condenser is the high-temperature (heat-rejection) side of the system.

Mechanical compression chillers are classified by compressor type: reciprocating, rotary screw, centrifugal and friction less centrifugal.

Reciprocating : –

Similar to a car engine with multiple pistons, a crankshaft is turned by an electric motor, the pistons compress the gas, heating it in the process. The hot gas is discharged to the condenser instead of being exhausted out a tailpipe. The pistons have intake and exhaust valves that can be opened on demand to allow the piston to idle, which reduces the chiller capacity as the demand for chilled water is reduced. This unloading allows a single compressor to provide a range of capacities to better match the system load. This is more efficient than using a hot-gas bypass to provide the same capacity variation with all pistons working. Some units use both methods, unloading pistons to a minimum number, then using hot-gas bypass to further reduce capacity stably. Capacities range from 20 to 125 tons.

Centrifugal  :  –

The centrifugal compressor operates much like a centrifugal water pump, with an impeller  compressing the refrigerant. Centrifugal chillers provide high cooling capacity with a compact design. They can be equipped with both inlet vanes and variable-speed drives to regulate control chilled water capacity control. Capacities are 150 tons and up.

Compact Heat Exchangers

Compact Heat Exchangers

Compact Heat Exchangers

The core of a compact heat exchanger is a set of heat-transfer plates.

The plates form channels where the hot and cold media flow on alternate sides. Most models have flat plates but in a spiral heat exchanger they have been curled up to form a spiral.The highly turbulent flow gives compact heat exchangers high heat transfer efficiency. The overall heat transfer coefficient is up to five times greater for a compact heat exchanger than a shell-and-tube. This means a compact heat exchanger is much smaller than a comparable shell-and-tube.

Crossing temperatures and close temperature approach

The overall flow of the two media is counter-current in a compact heat exchanger, i.e. the hot medium exits where the cold medium enters. This means the cold medium can be heated to a temperature very close to that of the entering hot medium. The temperature difference, ΔT, can be as low as 2°C (3.6°F).

The counter-current flow allows a compact heat exchanger to operate with crossing temperatures, meaning the cold medium can have a higher exit temperature than the exiting hot medium.

The close temperature approach means the heat exchanger requires less of the utility medium or you can use one with a temperature closer to that of the process medium. Both cases result in lower operating costs.

The combination of a close temperature approach and crossing temperatures makes it possible to recover maximum amounts of heat from the process and put it to use in other parts of the plant.

Compact Heat Exchangers for  Key Features : –

  • Contains revised content, covering industrially available exchangers, recent fouling theories, and reactor types
  • Includes useful comparisons throughout with conventional heat exchangers to emphasize the benefits of CPHE applications
  • Provides a thorough system view from commissioning, operation, maintenance, and design approaches to reduce fouling and fouling factors
  • Compiles all aspects of theory, design rules, operational issues, and the most recent developments and technological advancements in compact heat exchangers.

U Tube bundle Heat Exchangers

U Tube bundle Heat Exchanger

U Tube bundle Heat Exchangers

A heat-exchanger system consisting of a bundle of U tubes (hairpin tubes) bounded by a shell (outer vessel); one fluid flows through the tubes, and the other fluid flows through the shell, in the order of the tubes is U Tube bundle Heat Exchangers. Multitherm can duplicate any obtainable bundle to include dimensions, materials and performance. We can build “U” tube bundles, straight tube “floating” tube bundles, or we can retube fixed tube sheet heat exchangers when the bundles is not removable. multitherm is not locked into any one material. Most bundles tend to be build with copper tubes and steel tube sheets.

U Tube bundle Heat Exchangers Description : –

There can be a lot of variations on the shell and tube design. Typically, the ends of each tube are associated to plenums (sometimes called water boxes) through holes in tube sheets. The tubes may be straight or bent in the shape of a U, called U-tubes. In nuclear power plants called pressurized water reactors, large heat exchangers called steam generators are two-phase, shell-and-tube heat exchangers, which typically have U-tubes. They are used to boil water recycled from a surface condenser into steam to drive a turbine to produce power. Most shell-and-tube heat exchangers are 1, 2, or 4 pass designs on the tube side. This refers to the number of times the fluid in the tubes passes through the fluid in the shell. In a single pass heat exchanger, the fluid goes in one end of each tube and out the other. Surface condensers in power plants are often 1-pass straight-tube heat exchangers (see Surface condenser for diagram). Two and four pass designs are common because the fluid can enter and exit on the same side. This makes construction much simpler.

There are often baffles directing flow through the shell side so the fluid does not take a short cut through the shell side leaving ineffective low flow volumes. These are generally attached to the tube bundle rather than the shell in order that the bundle is still removable for maintenance. Counter current heat exchangers are most efficient because they allow the highest log mean temperature difference between the hot and cold streams. Many companies however do not use single pass heat exchangers because they can break easily in addition to being more expensive to build. Often multiple heat exchangers can be used to simulate the counter current flow of a single large exchanger.

 

Water Treatment Chemical

Water Treatment Chemical

Water Treatment Chemical

We are engaged in offering a wide range of Water Treatment Chemicals formulated using quality ingredients.the Water Treatment Plant, the ground water is softened using lime, filtered, fluoridated, and disinfected using chlorine the Water Treatment Plant, the groundwater is softened using lime, filtered, fluoridated, and disinfected using chlorineextensively used to purify and treated water and making it suitable for industrial, domestic and household purposes. Our range of chemicals is developed to improve various problems associated with water treatment such as scale, corrosion, bio-fouling and suspended solids.

This page is intended to provide you with a description of some common water treatment chemicals, along with links to commercial suppliers.

  • Boiler Water Chemicals : We offer speciality chemicals for boiler water treatment for small, medium and high pressure boilers.
  • Cooling Water Chemicals : To control corrosion, scaling and microbial fouling in cooling towers and closed cooling water circuits.
  • Fuel Additives & Fireside chemicals : Designed to condition fuel for better combustion performance and operation of system and fireside chemicals for keeping heat transfer surfaces clean.
  • Polyelectroytes (Flocculants) : Water soluble organic polymers for solid liquid separation uses are for raw water clarification and in process applications for steel, mining, aluminum, oil and sugar processing industries & effluent treatment plant.
  • Reverse Osmosis Chemicals : Thermax offers a complete range of R O chemical’s (NSF certified) which includes antiscalant, membrane cleaning chemicals & Biocides.
  • Sugar Chemicals : For sugar juice clarification, scale inhibition in evaporators and mill sanitation chemicals & viscosity reducers in processes of sugar industry.

Some risks associated with using copper-based algicides include : –

  • The accumulation of copper in the sediments;
  • The growth of species of blue-green algae that are resistant to the algicide may cause greater water quality problems;
  • The mass release of toxins from the algal cells;

Water Treatment Chemical Application : –

  • Agriculture
  • Airport
  • Cell tower
  • Health care facilities
  • Hotels and motels
  • Industrial security
  • Oil and gas exploration
  • Radio and television station
  • Sea port security
  • Schools and collages & universities
  • Water & waste water plant
  • Bio-chemistry lab
  • Research center

Evaporator Coil Cooler

Evaporator Coil Cooler

Evaporator Coil Cooler

Fin Type Cooler are produced in forced draught and induced draught designs, and in single and multi-fan arrangements, depending customer specifications and requirements, We are the professional Fin Type Coolerand air cooled condenser manufacturers, tubes in copper and fins are aluminium MOC we use 5/8’ or 3/8’and ½’ OD copper tubes as per customer specification, all tubes are well expanded tested for pressure and leak.

Function of Fin Fan Coolers : –

Air Cooled Heat Exchangers – also known as Fin Fan Coolers, are heat transfer devices for rejecting heat from a hot process fluids such as refinery products or steam directly, to the surrounding atmosphere.

Gireesh Fin Fan Coolers are basically that multiple rows of fin tubes with a fan to move lower temperature ambient air over the coils in order to cool the hotter fluid, just like a radiator in industrial an automobile. An industrial example is a unit large enough to reject the heat from a turbine exhaust steam condensation system.

Advantages of Fin Type Cooler : –

  • A great deal of water gets preserved on using Fin Type Cooler.
  • Less or no preparation needed as atmospheric air is in abundance
  • No formation of scale or heat exchanger cleaning is required
  • There are no mobile parts except for the fan and the motors. Hence the cooling tower maintenance is negligible
  • Dust, fly ash, living organisms or dirt do not get mixed up with process water
  • There are no constraints placed on the location of plant
  • No corrosions caused by air
  • This cooling tower performance ensures minimal environmental impact
  • Reduced annual operating expenses

Fin Type Cooler Applications :  –

  • Predominantly used for air compressor and power generating units for applications of engine water cooling.
  • Petroleum plant,
  • power utility,
  • steel manufacturing industry,
  • cement,
  • sugar factures,
  • Chemical and gas-processing industrials.
  • Chillier machines,
  • refrigeration system
  • petrochemical refineries

 

Vertical Shell and Tube Heat Exchangers

Vertical Shell and Tube Heat Exchangers

Vertical Shell and Tube Heat Exchangers

Vertical Shell and tube heat exchangers consist of a series of tubes. The second fluid runs over the tubes that are being heated or cooled so that it can either provide the heat or absorb the heat required.

One set of these tubes contains the fluid that must be either heated or cooled. Vertical Shell Tube Heat Exchanger is widely used in variety of application as a cooling solution.

Shell and tube heat exchangers are used for the majority of Swenson installations. The heating medium is typically steam which is normally condensed on the outside of the tubes to heat the liquor or slurry which flows inside the tubes.

Both vertical and horizontal tube heat exchangers are utilized. The horizontal exchanger is used for installations with limited headroom or where maximum liquor submergence is needed to prevent surface boiling and subsequent salt precipitation on the tubes.

Heat exchangers are typically one or two passes and are designed for relatively low temperature rises in the solution. This limits the supersaturation of scaling components when heating materials with inverted solubility. In most applications, the steam-to-liquid delta-T is also limited to prevent mass boiling within the tubes or vaporization at the tube wall.

Internal tube supports are not normally required for vertical heat exchangers. The tubes are usually fastened mechanically to the top and bottom tubesheets by expansion of the tube into the tube holes.