Heat Transfer

Instantaneous Jet Heaters

Transvac's range of Instantaneous Jet Heaters provide a simple, low cost, silent and reliable method of heating liquids in-line.

By bringing the steam into direct contact with the cold liquid both the sensible and latent heat of the steam is fully dissipated within the liquid, making the Heaters very efficient.

Transvac Heaters are designed to perform this operation silently to prevent undue noise and wear normally associated with steam 'collapse'

Advantages

• Custom designed
• Simple to install
• Silent in operation
• Compact
• Rapid response to automatic control
• No residence time
• No flameproofing necessary
• Materials selected to suit process

Operation

Pressurised cold liquid is introduced to the Heater and is immediately accelerated through the combining nozzle, resulting in a local pressure drop. Pressurised steam enters the unit and is discharged into the liquid at high velocity, via a number of jets around the combining tube.

This method of combining steam and liquor prevents 'backing up' should the steam be under a much higher pressure than the liquid.

The two streams combine and mix intimately fully condensing the steam silently and instantaneously.

Construction

Construction is tailored to suit each application with either single units or complete systems available. Typical materials of construction include carbon steel, stainless steel, hastelloy, PTFE etc. Connections are screwed, flanged or sanitary. Proprietary and recognised codes of practice are used including ASME, BS 5500, Stoomwezen, etc.

Hot Water Generation Units

Hot water generation system incorporating
a Transvac Instantaneous Jet heater

For process or service water heating requirements incorporating shell & tube, plate or steam jet units for indirect or direct contact heating technology.

Transvac offer single units or skid mounted systems.

Shell & Tube Heat Exchangers

Shell and Tube Heat Exchanger: U-tube Type

The most common designs of heat exchangers available are the 'U' tube, fixed plate, floating head and concentric tube type. All offer different operational features to meet most applications. Transvac manufactures to recognised codes of practice such as TEMA, ASME, BS5500, STOOMWEZEN, A.D. MERKBLATTER etc. and in a wide range of materials of construction.

Direct Injection Heaters

Stainless Steel Direct injection Heater

Transvac's range of Direct Injection Heaters are used to silently heat fluids in tanks. Maximum efficiency is maintained by bringing the process fluid and steam into direct contact, the sensible and latent heat being fully utilised. Control valves, pumps, instrumentation and pipework can be supplied to provide a complete system.

Desuperheaters

Transvac direct contact Desuperheaters reduce the temperature of superheated steam to produce steam temperatures approaching saturation temperature (typically to within 3 deg.C of the saturation temperature). To cool the superheated steam a medium; usually water, is entrained and flashed into vapour by absorbing heat from the steam.

Typical applications :-

• To reduce the temperature of steam discharged from turbine by-pass systems on Power Plants for Heat Exchangers, Dump stations etc.
• To improve heat transfer of indirect contact Heat Exchangers - Shell & Tube , Plate type, Reactor Heating Jackets etc.
• To reduce the temperature of steam on direct contact applications - Food Cooking Kettles, In-line Steam Heaters, Tobacco Drying Plant and Paper Mills.

Send us your requirements using our Desuperheater Enquiry Form.

Advantages

• Low cost Simple, robust design
• No moving parts to wear
• Minimal steam pressure drop
• Flexible design options

Construction

Transvac Desuperheaters are available built to our own proprietary codes of practice or to ASME VIII div 1, PD5500, Stoomwezen and other recognized design codes. Units can be marked CE on request. Connections are sized to suit the process conditions. Standard materials of construction include carbon steel, stainless steel, chrome molybdenum steel etc., however we can also manufacture in other metals or alloys requested.

Which Desuperheater is right for my application?

This is a general guide and does not represent every option available.
Please contact us if you have any queries regarding this.

Spray type Desuperheaters

A simple type of in-line Desuperheater with cooling water injected into the centre of the unit via an atomizing nozzle sprayed in the direction of the steam flow. Transvac Spray Type Desuperheaters are available in two options :-

Simple Spray Type Nozzle Desuperheater (SND)

The assembly is designed for mounting on a suitable flanged branch on the steam pipework. A thermal sleeve installed down stream of the unit is recommended.

Complete Spray Type Desuperheater (STD)

A complete Desuperheater ready for installation including spray nozzle, nozzle housing, thermal sleeve and flanged shell.

Applications

Relatively constant load handling duties
Turndowns up to 3:1 depending upon conditions

Venturi Type Desuperheaters (VTD)

The venturi principle is used to create regions of high velocity and turbulence which produces intimate contact between the steam and cooling water.

Applications

Suitable for most general plant applications, except where high turndowns on cooling water are required

Steam Atomizing Type Desuperheaters (SAD)

A high pressure auxiliary steam supply is used to atomize the incoming water within the diffuser of the unit.

The auxiliary steam pressure needs to be at least 1.5 times the Desuperheater inlet pressure with a minimum pressure of 3 bar g.

Applications

Variable load handling duties up to 20:1

Desuperheating & Pressure Reducing Stations

Transvac can provide complete Desuperheating & Pressure reducing Stations including Control Valves, Temperature Sensors, Pressure Transmitters, instrumentation and pipework, all mounted on a support skid.

Steam Jet Thermocompressors

Transvac Steam Jet Thermocompressors are energy saving devices that compress low pressure steam, often waste steam, to a higher useable pressure.

Transvac Thermocompressors can contribute substantially in reducing energy costs by recovering waste or flash steam and putting it back into the process at a useful pressure. Thermocompressor technology can in many cases produce steam savings of 15 - 20%.

Transvac has been designing Steam Jet Thermocompressors for over 35 years and each unit is designed specifically to suit a customer's process requirements to ensure maximum operating efficiency.

Paper Processing

Typical schematic for paper processing application

The paper industry world-wide is now converting conventional cascade and trap based systems to Thermocompressor recirculation systems.

Transvac Thermocomprssors maximize flash steam recovery and enhance condensate removal from the drying cylinders by providing effective "blow off".

The result is improved machine efficiency, uniform heating surfaces, and higher operating speeds. Thermocompresssor can be installed on Yankee, MG cylinder or machines with multiple dryers including Blowthru and Steam trap systems.

Spirax Sarco Sweden have a great deal of experience with using Thermocompressors for Paper Mill applications.

Sugar Processing

Typical schematic for sugar refinery application

With Transvac Thermocompressors, vapour recovery from the last stage of the multi-stage evaporators results in substantial cost savings in a sugar plant.

Also, as most plants run a turbine for their power requirement, low pressure steam from the turbine exhaust can also be 'boosted' for reuse in the distillery.

Power Generation

With power demand increasing annually, a number of industries have opted for co-generation plants to ensure uninterrupted power availability.

Here, Transvac can recover low pressure steam from the turbine exhaust. 'Boosting' this low pressure steam to a higher usable pressure achieves substantial energy savings and improves plant efficiency.

Other Applications

Solvent Extraction Industry

Flash steam recovered from the condensate of the Desolventizing Toasters (DST) can be boosted through a Thermocompressor and re-used in solvent extraction processes. Condensate from cookers and evaporators can also be combined with the DST condensate to maximize flash steam recovery.

Pharmaceutical Industry

In bulk drug production, steam is used in reboilers, evaporator columns, and stills. Transvac Thermocompressors boost low pressure flash steam recovered from the condensate of reboilers and other equipment to increase production while reducing fuel bills.

Petrochemical Industry

Steam is the preferred medium of heat transfer in a number of petrochemical drying and distilling processes. Recovery of low pressure steam from turbine exhaust and condensate flash steam recovery from heat exchangers make Transvac Thermocompressors effective energy saving devices.

Other Applications

Transvac Thermocompressor systems can be used in numerous other applications where low pressure steam (either from a process, a flash vessel, or turbine exhaust) is available and boosted to a usable pressure by using high pressure motive steam. Typical generic applications involve recovering both condensate and flash steam using Thermocompressors.

As a result of our extensive experience, each Transvac Thermocompressor is individually designed for the specific application resulting in more efficient operation.