Shell-Tube Anodic Protection Acid Cooler CD-AP-80 80m² Heat Exchange Area 97% Sulfuric Acid Service Compact Design

The Carpe Diem CD-AP-80 is a compact shell and tube type anodic protection sulfuric acid cooler engineered for medium-scale industrial acid cooling applications. With an 80 square meter heat exchange surface and a rated capacity of 35,000 kilograms per hour of 97 percent H₂SO₄, this unit delivers dependable and efficient thermal performance within a remarkably compact footprint of only Φ550*6800*1000 millimeters. The shell and tube configuration features a 304L stainless steel shell with a 316L tube bundle comprising precision-drawn tubes of Φ19*2.0 millimeter specification with 5500 millimeter effective length, providing an optimal balance between heat transfer efficiency and structural robustness. Designed and manufactured under the Carpe Diem quality management system certified to ISO 9001 and built to ASME Section VIII Division 1 code with the U Stamp authorization, the CD-AP-80 incorporates a fully integrated anodic protection system that continuously maintains the stainless steel surfaces within their passive electrochemical potential range, effectively suppressing corrosion even under the most demanding concentrated acid service conditions.

The compact shell and tube design of the CD-AP-80 is purpose-built for installations where plot space is at a premium yet uncompromising corrosion resistance and thermal performance are non-negotiable requirements. The tube bundle arrangement employs a triangular pitch layout that maximizes tube count per unit shell diameter, achieving a high surface-area-to-volume ratio while preserving adequate flow passage for both the acid on the shell side and the cooling water on the tube side. A double tube sheet construction with an expansion joint at the shell-to-tube sheet interface accommodates differential thermal expansion between the 304L shell and the 316L tubes during heat-up and cool-down cycles, preventing thermally induced stress concentrations that could otherwise lead to premature tube-to-tube sheet joint failure. The anodic protection system utilizes Hastelloy C276 cathodes and high-purity platinum reference electrodes positioned strategically within the acid inlet and outlet channels to ensure uniform potential distribution across all acid-wetted surfaces, maintaining protective passive film integrity throughout the entire heat exchanger internals.

• Optimized Shell and Tube Configuration: The classic TEMA-type shell and tube layout with a triangular tube pitch delivers the highest practical surface-area-to-volume ratio, enabling efficient cooling of 35,000 kilograms per hour of 97 percent sulfuric acid within a compact unit envelope suitable for space-limited installations.
• Integrated Anodic Protection System: The potentiostatic control unit continuously monitors the electrochemical potential via platinum reference electrodes and adjusts the applied current through Hastelloy C276 cathodes to maintain all acid-wetted stainless steel surfaces in the stable passive region throughout the full operating temperature range.
• Double Tube Sheet Construction: The dual tube sheet design with an expansion bellows at the shell junction effectively isolates the acid and cooling water circuits while accommodating differential thermal expansion of up to 8 millimeters between the shell and tube materials during transient operating conditions.
• Compact Installation Footprint: Overall dimensions of only Φ550*6800*1000 millimeters allow the CD-AP-80 to be installed in existing acid circulation pump bays, absorption tower platforms, or inter-stage cooling stations without requiring major structural modifications.
• Low Maintenance Electrode Assembly: The Hastelloy C276 cathodes are mounted on flanged access nozzles with external electrical connections, enabling inspection and replacement of electrode elements during scheduled plant turnarounds without removing the tube bundle or breaking major process piping connections.
• Full Penetration Welded Joints: All tube-to-tube sheet joints are executed using automated orbital GTAW with full penetration, followed by liquid penetrant examination and helium leak testing of every individual joint to ensure zero cross-contamination between acid and cooling water circuits.

The CD-AP-80 is ideally suited for medium-capacity sulfuric acid cooling duties in fertilizer-grade acid production plants where acid concentration after the absorption system is typically maintained at 97 percent for direct use in phosphoric acid manufacturing. In chemical processing facilities producing sulfonated organic compounds and synthetic detergents, this cooler provides precise temperature control for the acid sulfonation reactor feed, ensuring consistent product quality by eliminating temperature-induced variations in sulfonation reaction rates. The unit is frequently specified as an inter-pass cooler in multi-stage sulfuric acid concentration plants where dilute acid is progressively concentrated through a series of evaporation stages and requires inter-stage cooling to maintain optimal evaporation driving forces. Dye and pigment manufacturing operations utilize the CD-AP-80 for cooling the sulfuric acid used in sulfonation and nitration reaction circuits, where accurate acid temperature regulation is essential for achieving target color strength and shade consistency in the final product. The cooler also serves effectively in metal pickling line acid recirculation systems, where continuous cooling of the sulfuric acid pickling bath maintains consistent pickling rates and prevents excessive acid fuming at elevated temperatures that would otherwise create hazardous working conditions and increase acid consumption through evaporation losses.

Each CDAP-80 Anodic Protection Sulfuric Acid Cooler is transported in naked packing with a heavy-duty welded steel protective frame that shields all external nozzles, flanged connections, and electrode housings from mechanical damage during transit. All open connections are sealed with metal blind flanges fitted with PTFE gaskets and desiccant-filled breather ports to prevent atmospheric moisture contamination of the internal stainless steel surfaces during storage at the project site. The anodic protection power supply and control cabinet, reference electrode assemblies, and cathode elements are individually packed in custom foam-lined export crates equipped with humidity indicator cards and tilt indicators for quality assurance during transportation. Carpe Diem supplies a complete quality dossier with each unit, including EN 10204 Type 3.1 material certificates covering all pressure boundary materials, a fabrication data book with weld procedure qualification records and NDE reports for all Category A and B welds, the ASME U Stamp Certificate of Authorization, and a detailed operating manual covering anodic protection system startup, shutdown, and troubleshooting procedures. Our field service engineers can be deployed for on-site supervision of cooler installation, initial commissioning of the anodic protection system, and comprehensive operator training to ensure safe and effective long-term operation of the equipment.