Shell-and-Tube Heat Exchangers Built for Performance

That depends in part on whether the thermal design of the heat exchanger has already been completed.

If you already have an exchanger datasheet, thermal design, HTRI output, existing equipment drawing or detailed specification, send us what you have. We can review that information and use it as the basis for developing the mechanical design and quotation.

If thermal design is still required, helpful process information may include:

• Fluids on the shell side and tube side
• Fluid flow rates
• Inlet temperatures
• Required outlet temperatures or heat-transfer duty
• Operating and design pressures and temperatures
• Allowable pressure drop
• Fluid properties and fouling factors, where available
• Materials of construction
• Applicable specifications or customer standards
• Physical or installation constraints
• Required delivery schedule

Don't worry if you don't have all of this information yet. Heat exchanger specifications often develop as the overall process design progresses. Send us the information you have, and we can help identify what additional information is needed to develop the thermal and mechanical design and prepare a quotation.

Fixed tubesheet, U-tube, and floating-head exchangers are three common shell-and-tube heat exchanger configurations. Each handles thermal expansion, cleaning, and maintenance differently, so the best configuration depends on your process and operating requirements.

In a fixed tubesheet exchanger, both tubesheets are welded directly to the shell. The design is relatively straightforward and can be economical to manufacture, but differential thermal expansion between the shell and tubes must be considered. Depending on the temperatures and materials involved, an expansion joint may be required. Mechanical cleaning of the shell side can also be more difficult because the tube bundle cannot normally be removed from the shell.

A U-tube heat exchanger uses tubes bent into a “U” shape and attached to a single tubesheet. The U-shaped tubes can expand and contract independently of the shell, making the design well suited to applications with significant temperature differences. The tube bundle can generally be removed for shell-side inspection or cleaning, although mechanical cleaning of the inside of the tubes can be more difficult around the U-bends.

A floating-head exchanger allows one end of the tube bundle to move independently of the shell. This accommodates differential thermal expansion while also allowing greater access to both the shell side and tube side for inspection and mechanical cleaning. The tradeoff is a more complex design with additional components, which generally makes a floating-head exchanger more expensive to manufacture.

If more than one configuration can meet your process requirements, we can help you understand the fabrication, maintenance, and cost implications of the available alternatives.

Yes. We can design and manufacture replacement shell-and-tube heat exchangers, including equipment that has been in service for many years.

Ideally, you can provide the original exchanger drawing, datasheet, or thermal analysis. If the existing heat exchanger has performed satisfactorily and you do not require a new thermal analysis, we can generally use the available design information as the basis for the replacement while performing the necessary mechanical design calculations to confirm the new exchanger meets current code requirements.

When designing a replacement, we can also consider existing dimensions, nozzle locations, supports, and other physical interface points. Maintaining these connections can be important when installing a replacement heat exchanger in an operating facility where modifying existing piping, foundations, or surrounding equipment would add significant cost or downtime.

If the original thermal analysis is unavailable—or if your process conditions have changed and you want to confirm or reevaluate heat exchanger performance—we can also coordinate a new thermal analysis.

You don't necessarily need a complete original engineering package to begin the conversation. Send us the drawings, datasheets, and process information you have, and we'll help determine what additional information is needed.

Shell-and-tube heat exchangers can be fabricated using a variety of materials, and different components of the same exchanger may use different materials. Depending on your specification, this can include carbon steel, stainless steels, duplex stainless steels and other corrosion-resistant alloys.

For example, a heat exchanger may use one material for the shell and another for the tubes, tubesheets or other components when the two fluid streams have different service requirements.

You or your process engineer should determine which materials are compatible with the process fluids and operating environment. Savannah Tank does not provide metallurgical or chemical-compatibility recommendations.

Once appropriate material options have been identified, however, we can help you understand the practical implications of those choices, including material availability, fabrication and welding requirements, relative cost and potential effects on project schedule.

For exchangers involving unusual materials or specialized material combinations, we encourage you to contact us early as lead times for these materials can be lengthy.

Savannah Tank’s internal quality-control process applies throughout fabrication of our shell-and-tube heat exchangers. Our QC team maintains material traceability and fabrication records, performs in-process and final inspections, coordinates required nondestructive examination (NDE), and oversees pressure testing and other project-specific inspection requirements. Because shell-and-tube heat exchangers contain separate pressure-retaining systems on the shell side and tube side, we hydrostatically test the shell side and tube side separately to verify the integrity of both pressure boundaries.

We also perform 100% liquid penetrant examination (PT) of tube-to-tubesheet welds on the shell-and-tube heat exchangers we manufacture.

When a shell-and-tube heat exchanger is manufactured and stamped in accordance with ASME Section VIII, Savannah Tank’s internal QC process is supplemented by Code-required independent inspection by an Authorized Inspector (AI). The AI performs required inspections during fabrication, reviews the applicable quality-control documentation—including Code calculations, MTRs, weld maps, welding procedures and inspection records—and witnesses the final required pressure tests before the exchanger is stamped and released.

Depending on the applicable code, mechanical design, and your specifications, additional inspection and nondestructive examination (NDE) can also be incorporated into the project. Testing may include radiographic testing (RT), ultrasonic testing (UT), positive material identification (PMI), dimensional inspection, and other project-specific examinations.

In addition to the Code-required Authorized Inspector on ASME-stamped exchangers, you are welcome to visit during fabrication and testing, and we can accommodate your designated third-party inspectors, witness points and hold points when required.

If you have an exchanger datasheet, inspection specification, or customer inspection and test plan (ITP), send it to us with your inquiry. We can review the requirements up front and incorporate the applicable inspection, NDE, witness points, testing and documentation into the quotation and manufacturing plan.