The right jacket for your reactor vessel can make all the difference between long-lasting, trouble-free equipment and frequent unplanned maintenance.
Ward Vessel & Exchanger can help you select the best design for your new unit, saving initial material and fabrication costs, improving heat-transfer efficiency and sparing downtime for repair or replacement of premature failures.
"We are one of the leading experts in jacketed pressure vessels. We will provide you with the best option for your process," said Jon Ward, president at Ward.
There are three options for jacketed vessels:
- Conventional jackets - for containing dangerous chemicals and high media flows - often requiring the added expense of increased inner wall thickness to handle high-pressure environments.
- Dimpled jackets - for smaller vessels in lower pressure environments, but the numerous welds on this reactor jacket can be labor-intensive and may be more susceptible to leaking.
- Half-pipe jackets - for cooling water, steam, hot oil and heat transfer fluid applications in high pressure/high media flow environments - ideal for high heat transfer applications. They can be susceptible to condensate or weld failures if not properly designed by an expert.
Half-pipes are the most cost-effective between the amount of heat transfer and overall reliability. For example, with a 90-inch OD, 316 stainless steel reactor vessel, a conventional jacket would cost about 30 percent more than a half-pipe. Dimpled jackets would cost approximately 10 percent less than half-pipe, but would only be viable at lower pressures and temperatures than the others - introducing welds more susceptible to failure.
Ward is a leading manufacturer of half-pipe reactors, investing in custom fit-up/welding equipment and developing its own proprietary fabrication process. It has a perfect track record of half-pipe reactors with no premature failures.
The automated system loads whole coils of 2 to 4-inch width pipe onto the shell at a pitch that yields optimal heat-transfer efficiency. Continuous coils allow Ward to fabricate entire jacket zones with a minimal number of butt welds - only introduced when coiling runs out. Minimizing and/or eliminating butt joints - the number one failure point - is a critical factor in the reactor's reliability.
"Without this equipment and our process, you would have to install by hand, resulting in butt joints every 1.5-2 turns of half-pipe," Ward said. "When fitting and welding by hand, a fabricator can't safely and successfully handle the entire coil, which is why the coil is then cut and installed in smaller sections."
Most fabricators tack weld the half-pipe to the shell manually, which can be time-consuming.
Ward's twin sub-arc welding process greatly reduces or eliminates the need for tack welds, cutting costly labor and speeding up the process. It also reduces or eliminates the stops and starts during the welding process - enhancing overall weld quality and reliability. Weld penetration and heat input are consistent throughout the process, resulting in uniform weld quality. Consistency becomes more difficult to achieve when equipment is fabricated manually.
"We provide full-pen welded half-pipe jackets all the time, but it is much more labor-intensive and expensive," said Bill Huffman, director of engineering at Ward. "Our process provides very reliable, high quality half-pipe welds without needing full-pen welds. Our process can be 60 percent the cost of a full penetration unit, so it becomes a true cost of ownership type of service and expected-life discussion with our client."
In addition, Ward's half-pipe specialists determined how to install half pipe onto dished heads more uniformly, with less stresses than the industry standard. Automated cutting equipment in Ward's Charlotte, North Carolina facility provides a precise fit-up of head half-pipe in 180-degree segments, with each concentric ring requiring a different cut angle. More precise rolling and cutting results in a product that can be installed manually onto each head with perfect gapping and minimal stresses to achieve the exact weld joint to meet customer needs.
For more information, visit sales@wardve.com or call (704) 568-3001.
