Air Cooled Heat Exchanger for Algeria Refinery | Extruded Fin Tubes

Air Cooled Heat Exchanger Project for an Algerian Refinery: Copper-Aluminum Extruded Finned Tubes Solve High-Temperature Heat Exchange Challenges

Project Overview

• Location: Algeria

• Industry: Downstream Oil & Gas (General Refinery)

• Equipment Type: Air Cooled Heat Exchanger (ACHX) Tube Bundles

• Core Technology: Bimetallic Extruded Fin Tubes (Copper Base Tube + Aluminum Fins)

As one of the largest oil and gas producers in Africa, Algeria hosts refineries that often operate in harsh environments—ranging from arid, scorching inland deserts with severe dust storms to coastal regions with high salinity. Our client required a batch of high-performance replacement tube bundles for their core refining unit to ensure stable cooling efficiency even during peak summer temperatures.

Due to the extremely high summer temperatures and the presence of salt in the coastal air, traditional heat exchange equipment is highly susceptible to thermal efficiency degradation and corrosion pitting. To ensure continuous production and meet energy efficiency targets, the client set extremely stringent requirements for the core heat exchange components.

Technology Selection: Why Copper-Aluminum Bimetallic Extruded Finned Tubes?

After a comprehensive evaluation of various heat exchange solutions, the project’s technical team ultimately decided to use copper-aluminum extruded finned tubes as the core material for the ACHE tube bundles. This decision was based on three major technical advantages:

1. Ultimate Thermal Conductivity and Fouling Resistance: The copper-aluminum composite tube combines the excellent thermal conductivity of copper with the large surface area of aluminum fins. Through a cold extrusion process, the copper tube and aluminum fins achieve a molecular-level bond, resulting in extremely low interfacial thermal resistance. Additionally, the smooth surface of the aluminum fins resists fouling, effectively preventing the increased thermal resistance commonly caused by crude oil deposits in refineries.
2. Superior Corrosion and Fatigue Resistance: To combat the high-salt fog environment of the Algerian coast, the naturally formed dense oxide film on the aluminum fins provides an excellent anti-corrosion barrier, while the inner copper base tube effortlessly handles complex media in refining processes.
3. Structural Stability: The extrusion process integrates the fins and the base tube into a single entity. Under long-term high-temperature, high-pressure, and fan vibration conditions, the tube will not experience the loosening or detachment issues common in traditional L-footed or embedded finned tubes, significantly extending the equipment’s maintenance-free lifecycle.

Air Cooled Heat Exchanger Project for an Algerian Refinery: Copper-Aluminum Extruded Finned Tubes

Solutions and Implementation Details

Based on the specific operating conditions of the refinery, we customized the following ACHE tube bundle solution:

1. Material Standards: The base tube is made of high-purity electrolytic copper (complying with ASTM B152 standards), and the outer layer is made of 6063 aluminum alloy, ensuring an elongation rate of over 25% under extreme temperature differences to resist thermal stress fatigue.
2. Structural Optimization: A high-fin design is adopted with a fin height-to-width ratio precisely controlled at 3.8:1 and a fin pitch of 8mm. This design maximizes the heat exchange area while effectively preventing dust blockage caused by North African sandstorms, ensuring maximum turbulence on the air side.
3. Rigorous Quality Control: Every batch of tubes undergoes a 1.5MPa hydrostatic test and EDX spectrometry analysis to ensure the copper core ratio meets standards and the composite layer is free from delamination. The finished product sampling rate is as high as 20%, with a 100% weld flaw detection pass rate.

Bimetallic Extruded Fin Tubes for Air Cooled Heat Exchangers (ACHX) Most Commonly Used Standard Configurations

Copper-Aluminum Bimetallic Extruded Finned Tubes for Air Cooled Heat Exchanger

In actual engineering procurement for air coolers, the following two configurations (categorized by base tube Outer Diameter) account for over 85% of the global market demand:

Configuration 1: The 1″ Base Tube Combination (The Global Standard)

This is the most widely specified size in API 661 air coolers, offering an optimal balance between heat transfer surface area and tube-side fluid pressure drop.

• Base Tube OD: 25.4mm (1″)

• Fin OD: 57.15 mm(2-1/4) or 55 mm

• Fin Height: 15.875mm(5/8″) or 15 mm

• Fin Thickness: Base: approx. 0.45 – 0.5mm | Tip: approx. 0.25 – 0.3 mm(Tapered profile)

• Fin Pitch: 10 FPI (Fins Per Inch) is standard; 9 FPI is preferred for high-dust environments.

Configuration 2: The 1.25″ Base Tube Combination (Heavy-Duty / High-Flow)

Typically specified for heavy oil units, crude distillation units, or applications with extremely high volumetric flow rates and high tube-side pressure.

• Base Tube OD: 31.75 mm (1 -1/4″)

• Fin OD: 63.5 mm (2 -1/2″)

• Fin Height: 15.875  mm (5/8″)

• Fin Pitch: 10 FPI

Bimetallic Extruded Fin Tubes for Air Cooled Heat Exchangers (ACHX) Technical Specification Datasheet

This data table can be embedded directly into your website product pages or digital catalogs:

Copper-Aluminum Bimetallic Extruded Fin Tubes for Fin Fan Cooler

Engineering Insights: Material Selection for Harsh Environments

• Fin Pitch Optimization (9 FPI vs. 10 FPI):

  While 10 FPI is the standard default for maximizing surface area, for regions prone to severe dust storms—such as Algeria, the Middle East, or North Africa—we highly recommend 9 FPI. A slightly wider fin gap significantly minimizes dust accumulation, reduces fouling rates, and makes high-pressure water jet cleaning far more effective.

• Heavy-Wall Base Tubes for Corrosive Service:

  Refinery overhead condensers encounter high process pressures and aggressive chemical media. We recommend a minimum base tube wall thickness of 2.11 mm(14 BWG) or 2.77 mm(12 BWG) instead of the standard 1.65 mm (16 BWG) to provide an adequate corrosion allowance and ensure structural safety under high-pressure cycles.

• Bare Ends Customization:

  For secure tube-to-tubesheet jointing (welded or expanded), the aluminum sleeves are cleanly stripped at both ends. For standard air cooler bundles, we supply a bare length of 50 mm to 100 mm, treated with temporary rust preventatives or anti-oxidation coatings based on shipping requirements.

Project Outcomes: Stable Operation and Energy Efficiency Leap

• Breakthrough in Heat Transfer Efficiency: In the crude oil preheating section, the heat transfer coefficient consistently exceeded 85 W/(m²·K), improving thermal efficiency by approximately 35% compared to the old equipment, which drastically reduced fuel consumption in the heating furnace.
• Extended Service Life: After over 18,000 hours of continuous operation, shutdown inspections revealed no corrosion penetration or fin collapse in the tube bundles, maintaining equipment availability at over 99.2%.
• Plummeting O&M Costs: Thanks to the outstanding fouling resistance and anti-vibration performance of the copper-aluminum extruded tubes, the cleaning cycle of the ACHE was more than doubled, significantly reducing the refinery’s downtime for maintenance and labor costs.

Extruded Finned Tubes Air Cooled Heat Exchanger for Algerian Refinery

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