Energy & heat recovery · All-stainless fusion-bonded BPHE

All-Stainless BPHE for Biogas Cooling

Copper-free compact heat exchanger selection for cooling biogas from 70.4°C to 25°C.

full stainless brazed heat exchanger
Original image from the legacy HEXNOVAS project record
01

Project summary

Challenge

Cool a gas stream where copper-containing construction was undesirable while retaining a compact installation.

Engineering response

An all-stainless bonded plate exchanger was evaluated around gas composition, condensate behavior, pressure drop and the 70.4°C to 25°C temperature program.

Outcome

The compact copper-free construction provides a corrosion-conscious alternative to a larger shell-based arrangement.

  • 70.4°C gas inlet
  • 25°C target outlet
  • Copper-free fluid path
  • Compact gas cooler
02

Original project record

Full Stainless Steel Brazed Plate Heat Exchanger for Biogas Cooling

A compact, copper-free, high-pressure heat exchanger solution designed for cooling biogas from 70.4°C to 25°C using cooling water, with 100% SS316 stainless steel construction and reinforced pressure plates for reliable industrial operation.

Application Background

In biogas treatment systems, gas cooling is required to reduce gas temperature before downstream processing, gas cleaning, compression, or utilization. The gas stream normally contains methane, carbon dioxide, water vapor, and a small amount of oxygen. Because the medium may contain moisture and corrosive components, material selection is critical.

For this application, the customer required one heat exchanger to cool biogas with water as the cooling fluid. The selected design is a full stainless steel brazed plate heat exchanger , without copper, rated for approximately 30 bar pressure class . The exchanger uses stainless steel brazing technology and front/back reinforced clamping plates to improve mechanical strength and pressure resistance.

Design Conditions

Why Copper-Free Full Stainless Steel Construction Is Used

Standard copper brazed plate heat exchangers are widely used in HVAC and water-to-water applications. However, for biogas cooling, copper is not always the preferred choice because the gas may contain moisture, acidic condensate, sulfur compounds, or other corrosive contaminants depending on the upstream process.

A copper-free full stainless steel brazed heat exchanger eliminates copper from the heat transfer core. The plates and brazing material are stainless steel based, making the unit more suitable for applications where corrosion resistance, cleanliness, and material compatibility are more important than the lowest initial cost.

Heat Exchanger Structure

The selected unit is not a traditional gasketed plate heat exchanger and not a conventional shell and plate unit. It uses a compact plate pack made by stainless steel brazing. The flow channels are formed between corrugated stainless steel plates, creating high turbulence and efficient heat transfer within a very small footprint.

To increase pressure resistance, the brazed stainless steel core is supported by front and rear reinforced clamping plates . This structure improves mechanical stability and allows the exchanger to handle higher pressure duties compared with a light-duty brazed unit.

Main Structural Features

  • 100% SS316 stainless steel wetted construction
  • Copper-free brazed plate core
  • Reinforced front and back plates for higher pressure resistance
  • Compact plate channel structure with high heat transfer efficiency
  • Suitable for approximately 30 kg/cm² pressure class design
  • Smaller footprint compared with shell and plate heat exchangers

Comparison with Shell and Plate Heat Exchanger

Shell and plate heat exchangers are also suitable for gas cooling and industrial services, especially where very high pressure, large flow rate, or special mechanical requirements are involved. However, for this medium-sized biogas cooling duty, a full stainless steel brazed plate heat exchanger provides a more economical and compact solution.

Performance Advantage in Biogas Cooling

The biogas enters the heat exchanger at 70.4°C and leaves at 25°C. Cooling water enters at 8°C and leaves at 18°C. This temperature program is suitable for a compact plate design because the plate channels provide strong turbulence, high surface utilization, and efficient heat transfer even with a small exchanger volume.

Compared with bulkier shell and plate equipment, the full stainless steel brazed plate solution reduces installation space, lowers equipment weight, and simplifies piping arrangement. For packaged biogas systems, skid-mounted equipment, and modular process units, this compact construction is a major advantage.

Typical Applications

  • Biogas cooling before gas treatment
  • Gas cooling before compression
  • Wastewater treatment plant biogas systems
  • Landfill gas cooling and conditioning
  • Anaerobic digestion gas cooling
  • Compact industrial gas-to-water cooling packages

Why HEXNOVAS Recommends This Solution

For this project, the full stainless steel brazed plate heat exchanger provides a practical balance between corrosion resistance, cost, size, and thermal efficiency. It is more economical than a shell and plate exchanger for this duty, while still offering a copper-free stainless steel construction suitable for demanding biogas cooling conditions.

The reinforced clamping plate design also gives the exchanger better pressure resistance, making it suitable for industrial systems where compact size and reliable pressure performance are both required.

FAQ

Biogas may contain moisture and corrosive contaminants. A copper-free full stainless steel brazed exchanger provides better material compatibility than a standard copper brazed unit.

No. This is a compact stainless steel brazed plate structure with reinforced front and rear plates. It is smaller and generally more economical for this type of duty.

The reinforced front and back plates improve mechanical support and pressure resistance, allowing the unit to handle higher pressure requirements than a light-duty brazed plate exchanger.

Yes. It can be considered for other gas-to-water cooling duties where stainless steel construction, compact size, and high thermal efficiency are required.

Need a Copper-Free Stainless Steel Heat Exchanger for Gas Cooling?

HEXNOVAS can provide compact full stainless steel brazed plate heat exchangers for biogas cooling, industrial gas cooling, process water cooling, and corrosion-sensitive thermal applications.

Application Data

Gas: Biogas

Gas In / Out: 70.4°C / 25°C

Water In / Out: 8°C / 18°C

Material: 100% SS316

Design: ASME

Related Products

Best For

Biogas cooling, compact gas-to-water cooling, stainless steel process cooling, and copper-free industrial heat transfer systems.

ParameterBiogas SideWater Side
Flow Rate814 kg/h4500 kg/h
Inlet Temperature70.4°C8°C
Outlet Temperature25°C18°C
Maximum Allowable Pressure Drop20 kPaAccording to hydraulic design
Material Requirement100% SS316 stainless steel
Design StandardDesigned in accordance with ASME requirements
ItemFull Stainless Steel Brazed Plate Heat ExchangerShell and Plate Heat Exchanger
CostLower for compact dutiesHigher due to shell, welding, and heavier fabrication
Heat Transfer EfficiencyHigher, due to thin plates and turbulent channelsGood, but usually requires larger surface area
FootprintVery compactLarger and heavier
Material100% SS316, copper-freeCan be stainless steel, but cost increases significantly
Pressure ResistanceEnhanced by reinforced front and rear platesStrong mechanical design, suitable for severe conditions
Best FitCompact gas cooling, water cooling, industrial process coolingLarge duty, very high pressure, special code requirements