Small Shell and Tube Heat Exchanger | Compact / Skid-Mounted | Fixed Tube Sheet / U-Tube | Materials: CS / 304 / 316L / Ti
Overview – Compact Shell and Tube Heat Exchanger
A small shell and tube heat exchanger is a compact heat transfer unit designed for low to moderate duty applications where plot space, installation time, and capital cost are constrained. Typical shell diameters range from DN100 to DN500, with heat transfer areas from 1 m² to 50 m² per unit.
This product is designed and manufactured per TEMA Class C or B, ASME Section VIII Division 1, and GB/T 151. It is suitable for process cooling, sample conditioning, hydraulic oil cooling, steam sampling, pilot plant service, and auxiliary systems in larger plants.
Typical Applications
| Application | Tube-Side Fluid | Shell-Side Fluid | Typical Duty |
|---|---|---|---|
| Hydraulic oil cooler | Hydraulic oil | Cooling water | 5 – 50 kW |
| Sample cooler | Process sample | Cooling water | 1 – 10 kW |
| Steam sampling | Steam / condensate | Cooling water | 2 – 20 kW |
| Pilot plant reactor | Process fluid | Heating or cooling medium | 5 – 100 kW |
| Compressor oil cooler | Lubricating oil | Cooling water | 10 – 80 kW |
| Auxiliary lube oil cooler | Turbine lube oil | Cooling water | 20 – 150 kW |
| Chemical dosing line | Chemical solution | Cooling or heating fluid | 1 – 30 kW |
Construction Types
Fixed Tube Sheet (TEMA L / M / N)
Tubes fixed at both ends into stationary tube sheets
Shell and tube sheets welded or bolted
Suitable for clean shell-side fluids and moderate temperature differential
Lowest cost and simplest construction
U-Tube (TEMA U)
Tubes bent into U-shape, both ends fixed to a single tube sheet
Tubes expand freely, accommodating large temperature differential
Bundle removable for shell-side cleaning
Suitable for high temperature differential and high-pressure tube side
Floating Head (TEMA P / S / T)
One tube sheet fixed, one floating
Bundle fully removable for mechanical cleaning on both sides
Suitable for fouling service and large temperature differential
Higher cost than fixed or U-tube
Design Parameters
| Parameter | Range | Note |
|---|---|---|
| Shell diameter | DN100 – DN500 | Compact footprint |
| Tube OD | 12.7 mm – 25.4 mm | Smaller OD for higher pressure |
| Tube wall thickness | 1.0 mm – 2.5 mm | Per ASME VIII-1 UG-27 |
| Tube length | 500 mm – 3,000 mm | Limited by transport and handling |
| Heat transfer area | 1 m² – 50 m² | Per unit |
| Design pressure (tube side) | Up to 4.0 MPa | Higher available per special design |
| Design pressure (shell side) | Up to 2.5 MPa | Higher available per special design |
| Design temperature | -20°C to +400°C | Material dependent |
| Tube pitch | 1.25 × – 1.5 × tube OD | Triangular or square arrangement |
| Number of tube passes | 1, 2, or 4 | Per thermal design |
| Number of shell passes | 1 or 2 | Per thermal design |
Material Selection
Tube and Tube Sheet Materials
| Material | Specification | Temperature Range | Application |
|---|---|---|---|
| Carbon steel | SA-179 / SA-106 Gr.B | -20°C to +425°C | Water, oil, steam, clean fluids |
| Stainless 304 / 304L | ASTM A213 | -196°C to +400°C | Mildly corrosive fluids, clean steam |
| Stainless 316 / 316L | ASTM A213 | -196°C to +400°C | Organic acids, salt solutions, chlorides ≤ 200 ppm |
| Titanium Gr.2 | ASTM B338 | -40°C to +230°C | Seawater, brine, high-chloride service |
Shell Materials
Carbon steel SA-516 Gr.70 for non-corrosive shell-side fluids
Stainless 304L / 316L for corrosive shell-side fluids
Shell material may differ from tube material to optimise cost
Gasket Materials
| Gasket Type | Temperature Range | Pressure Limit | Application |
|---|---|---|---|
| Non-asbestos fibre | -40°C to +250°C | ≤ 4.0 MPa | General service |
| Spiral wound (SS + graphite) | -196°C to +450°C | ≤ 10.0 MPa | High temperature and pressure |
| PTFE envelope | -40°C to +200°C | ≤ 2.0 MPa | Corrosive and high-purity service |
Thermal Design Parameters
| Parameter | Typical Range | Note |
|---|---|---|
| Overall heat transfer coefficient (water-to-water) | 800 – 1,500 W/m²·K | Depends on velocity and fouling |
| Overall heat transfer coefficient (oil-to-water) | 200 – 600 W/m²·K | Depends on oil viscosity |
| Overall heat transfer coefficient (steam-to-water) | 1,000 – 2,500 W/m²·K | Depends on steam quality |
| Tube-side velocity (liquid) | 0.5 – 2.5 m/s | Higher velocity increases HTC but also pressure drop |
| Shell-side velocity (liquid) | 0.3 – 1.5 m/s | Limited by allowable pressure drop |
| Allowable tube-side pressure drop | 20 – 50 kPa | Per application requirement |
| Allowable shell-side pressure drop | 20 – 50 kPa | Per application requirement |
| Fouling factor (water) | 0.0001 – 0.0003 m²·K/W | Per TEMA table |
| Fouling factor (oil) | 0.0002 – 0.0005 m²·K/W | Per TEMA table |
Standard Configurations
Fixed Tube Sheet – Bolted Bonnet
Shell: Seamless pipe or rolled plate
Tube sheet: Bolted between shell flange and channel flange
Channel: Bolted bonnet with flanged connections
Connections: Threaded NPT or flanged per ASME B16.5
Typical application: Cooling water, lube oil, sample cooling
U-Tube – Removable Bundle
Shell: Seamless pipe with flanged closure at one end
Tube sheet: Single stationary tube sheet
Bundle: Removable for shell-side cleaning
Connections: Flanged per ASME B16.5
Typical application: High temperature differential, steam service
Skid-Mounted Unit
Heat exchanger mounted on a structural steel skid with piping, valves, and instrumentation
Includes: Temperature gauges, pressure gauges, flow indicators, and control valves as required
Skid dimensions: Typically 1.0 m × 0.8 m to 2.5 m × 1.5 m
Lifting lugs provided for transport and installation
Typical application: Pilot plant, auxiliary systems, remote locations
Fabrication and Inspection
Tube-to-Tubesheet Joint
Expanded only: Hydraulic expansion at 160 – 200 MPa, hold 5 – 8 seconds
Welded only: GTAW fillet weld, leg 1.5 – 2.0 mm
Weld + expand: Seal weld plus expansion for cyclic service
100% penetrant testing on welded joints
Pull-out test on first article, target ≥ 20 MPa for carbon steel
Hydrostatic Test
Test pressure: 1.3 × design pressure per ASME VIII-1 UG-99
Hold time: ≥ 30 minutes
Acceptance: Zero pressure drop and no visible leakage
Test medium: Clean water with corrosion inhibitor
Dimensional Check
Shell diameter and length
Tube sheet hole pattern
Nozzle orientation and projection
Overall dimensions and lifting lug location
Documentation Per Shipment
Material test certificates per EN 10204 3.1 or 3.2
TEMA datasheet completed per design
Dimensional inspection report
Hydrostatic test report with pressure chart
NDE reports for PT and RT as performed
Weld procedure specification and procedure qualification record
As-built drawing
Operation and maintenance manual
Selection Checklist – Small Shell and Tube Heat Exchanger
Tube-side fluid and shell-side fluid names
Inlet and outlet temperatures for both sides
Design pressure for both sides
Design temperature for both sides
Required heat duty in kW
Allowable pressure drop for both sides
Material preference for tubes and shell
TEMA type preference: Fixed, U-tube, or floating head
Connection type: Threaded or flanged
Mounting: Standalone or skid-mounted
Instrumentation requirements
Applicable standard: TEMA, ASME VIII-1, or GB/T 151
Design Limitation Statement – Small Shell and Tube Heat Exchanger
The small shell and tube heat exchanger is subject to the following limitations:
It is designed only for the specified pressure and temperature. Operation outside these limits voids the design.
Fixed tube sheet design may require an expansion joint if the temperature differential between tubes and shell exceeds 60°C for carbon steel or 40°C for stainless steel.
Tube-side solids content above 2% by weight is not recommended without upstream filtration.
Mechanical cleaning of the tube side requires straight tubes and access to both tube sheet faces. U-tube bundles cannot be mechanically cleaned inside the tubes.
For fouling service, a floating head or U-tube design with removable bundle is recommended.
Hydrotest water for stainless steel must have chloride content ≤ 50 ppm to prevent stress corrosion cracking.
Skid-mounted units require a level foundation and adequate access for maintenance.
