Rigorously NDT Inspected Anodic Protection Sulfuric Acid Cooler CD-AP-70 Compact 70m² 304L Shell Design

The Carpe Diem CD-AP-70 Anodic Protection Sulfuric Acid Cooler is a compact yet rigorously quality-assured shell and tube heat exchanger designed for smaller-scale sulfuric acid cooling applications where reliability and inspection integrity are paramount. With a 70m² heat exchange area, this unit cools 94.5% concentrated sulfuric acid from 63°C to 36°C at a flow rate of 28,000 Kg/h. The cooler features a 304L stainless steel shell housing a 316L stainless steel tube bundle with precision-drawn tubes measuring Φ16 × 1.5 × 5200mm. What truly distinguishes the CD-AP-70 is our uncompromising multi-stage non-destructive testing program. Every single unit undergoes a comprehensive five-stage NDT protocol: 100% radiographic examination of all butt welds, liquid dye penetrant inspection of all fillet and branch connection welds, ultrasonic thickness verification of all pressure boundary components, helium mass spectrometer leak testing of the complete tube bundle assembly, and full hydrostatic pressure testing of both shell and tube circuits. This exhaustive inspection regime, combined with the integrated anodic protection system featuring platinum-clad titanium anodes and Hastelloy C-276 cathodes, ensures that each CD-AP-70 delivers leak-free, corrosion-free operation from day one of commissioning. The compact footprint makes this model particularly suitable for pilot plants, laboratory-scale acid production units, small-capacity sulfur-burning plants, and specialized chemical processing facilities where space is at a premium but quality cannot be compromised.

• Comprehensive Multi-Stage NDT Protocol: Every CD-AP-70 unit is subjected to a rigorous five-stage non-destructive testing sequence including 100% radiographic testing of all Category A and B butt welds per ASME Section V, liquid penetrant examination of all fillet welds, ultrasonic thickness gauging of all shell and head plates, helium leak detection with a maximum allowable leak rate of 1×10&supminus;&sup6; Pa·m³/s, and shell-side plus tube-side hydrostatic testing at 1.5 times design pressure with a 30-minute minimum hold period.
• Compact Space-Efficient Footprint: With overall dimensions of Φ520 × 6750 × 960mm and a weight of only 3,600 Kg, the CD-AP-70 can be installed in confined equipment bays, elevated steel structures, and modular skid-mounted process packages without requiring extensive structural reinforcement or dedicated foundation pads.
• Reliable Anodic Protection for Small-Scale Operations: The integrated anodic protection system is fully self-contained within a compact wall-mount control panel, making it ideal for small plants that may not have a dedicated instrument room. The system automatically maintains the protective passive film on all acid-wetted surfaces with minimal operator intervention.
• Enhanced Tube-Side Heat Transfer: The use of smaller-diameter Φ16 × 1.5mm tubes allows for a greater number of tubes within the compact shell diameter, maximizing the heat transfer coefficient on the tube side. The thin 1.5mm wall thickness minimizes conductive thermal resistance while maintaining full mechanical integrity at the design pressure.
• Complete NDT Documentation Package: Unlike suppliers who provide only summary NDT reports, Carpe Diem delivers the complete radiographic film package (digital format), all penetrant inspection photographs, ultrasonic thickness mapping reports, and the full helium leak test data log with every CD-AP-70 unit. This transparency enables client inspectors and third-party surveyors to independently verify the inspection results.
• Precision Tube Bundle Construction: All tubes are individually roller-expanded into the tubesheet followed by seal welding at both tube ends. Post-expansion, each tube is gauged for correct expansion percentage using a precision bore gauge, and a sample of tubes undergoes pull-out testing to verify the mechanical strength of the tube-to-tubesheet joint.
• Low-Capacity Optimized Design: With a 28,000 Kg/h acid flow rate and 70m² heat exchange area, this model provides efficient thermal performance without the excess capacity and associated capital cost of larger units, making it the cost-effective choice for pilot plants and small production lines.

The CD-AP-70 Anodic Protection Sulfuric Acid Cooler is specifically designed for small-capacity sulfuric acid production and handling applications where full-scale industrial coolers would represent excessive capital investment and unnecessary excess capacity. Primary applications include pilot plant and laboratory-scale sulfuric acid production units used for process development and catalyst testing programs. The unit is also ideally sized for small sulfur-burning acid plants producing 50 to 150 metric tons per day, serving as both the absorption tower acid cooler and the final product acid trim cooler. In the chemical processing industry, the CD-AP-70 is deployed in batch sulfonation reactors, titanium dioxide sulfate-process pilot facilities, and small-scale metal pickling acid recovery systems. Pharmaceutical and specialty chemical manufacturers using high-purity sulfuric acid as a reaction medium or catalyst appreciate the compact footprint and rigorous quality documentation. The unit is also commonly specified for university chemical engineering laboratories and government research facilities where safety, reliability, and comprehensive inspection records are mandatory procurement requirements. Educational institutions conducting corrosion research on advanced anodic protection techniques frequently select this model as a reference platform.

The CD-AP-70 quality assurance program is among the most thorough in the industry for equipment of this size class. All incoming materials are verified against EN 10204 Type 3.1 certified mill test reports with additional positive material identification testing performed on all pressure-retaining components using portable optical emission spectroscopy. Welding operations are executed exclusively by ASME Section IX certified welders under fully qualified welding procedure specifications, with continuous monitoring by certified welding inspectors. The multi-stage NDT program includes 100% radiographic examination of all butt welds, 100% liquid penetrant examination of all fillet welds and nozzle attachment welds, ultrasonic thickness verification of all formed head knuckle regions, ferrite content measurement of all stainless steel welds using a calibrated ferritescope, and a comprehensive helium mass spectrometer leak test on the assembled tube bundle. Hydrostatic pressure testing is conducted at 1.5 times design pressure with digital pressure recording for complete traceability. The anodic protection control panel undergoes a 24-hour burn-in test with simulated load conditions prior to shipment. For transport, the compact CD-AP-70 is secured to a welded steel base frame with heavy-duty bolted flange covers and all instrument ports sealed with stainless steel plugs. The complete unit is wrapped in vapor-phase corrosion inhibitor film and enclosed in heavy-gauge polyethylene sheeting. A weatherproof document pouch attached to the shipping frame contains the full quality dossier: material certificates, NDT reports with digital radiography files on USB, hydrostatic test charts, helium leak test certificate, anodic protection system FAT report, surface finish inspection records, ASME U Stamp Manufacturer's Data Report, and a comprehensive installation and operating manual.