Chemical industry
Did you know … that volcanoes are estimated to emit between 1 million to 7 million tonnes of HF per year ? This then falls to the ground within rain droplets
grow to USD 0.5 billion by 2030 , whilst a second predicts that demand for HF globe valves alone will top USD 2 billion by the same year . Whatever the actual value , the numbers remain impressive , with ongoing growth in HF ( and hence HF valves ) ascribed to increasing demand for products such as gasoline ( petrol ), diesel and petrochemicals . In terms of geography , North America has for decades spearheaded investment in refinery alkylation facilities . However , current and forward-looking growth seems to be focused in Asia . Reports from 2023 indicate that China had the highest refinery alkylation capacity in Asia at around 200 million barrels per day ( mbd ). Other key countries included Japan and India ( both around 100 mbd ). With total 2023 Asian alkylation capacity put at a shade under 590 mbd , that figure is expected to increase sharply to 760 mbd in 2028 .
Valves for alkylation - materials
At face value , the valves often found in HF service in alkylation facilities may sound and look familiar : gate valves , globe valves , piston check valves , swing check valves , plug valves , etc . However , manufacturers clearly continue to work in close alliance with ‘ the industry ’ to develop , engineer and manufacture valves that are fully geared to the demanding requirements of handling such a highly corrosive and toxic medium . To give a quick example : the avoidance of dead spaces in valve designs which can help to prevent certain forms of corrosion . Speaking of corrosion , several manufacturers state that , for the most severe applications such as for use with hot / wet HF , they produce valves with solid bodies and trims
from ‘ exotic ’ alloys like Monel or Hastelloy . For less critical environments solid Monel trims can be found in conjunction with carbon steel bodies ( with an appropriate corrosion allowance ). Incidentally , double-seal welding is often noted in conjunction with Monel seat rings and carbon steel body pockets . This creates a long-term barrier to prevent seat pocket corrosion . Special grades of Monel may be selected for the stems to minimise bending and / or twisting , whilst the seat rings and forged wedges may also be produced using specific Monel alloys to eliminate the risk of galling . Solid Monel again seems to be the norm for such components . Manufacturers are also aware of the potential of stress corrosion cracking ( SCC ) due to the combined effects of mechanical stress and exposure to HF . This could be the case with bolts if HF were to leak through the flanges . Bolts destined for use on HF valves may be heat treated , which makes them less likely to crack after coming into contact with HF . Attention is also given to sealant injection ports , with double ball isolation systems deployed to ensure integrity . For on / off duty , plug valves with a PTFE liner seem to be a common selection . However , given the tools and training required to properly manufacture such valves , any repair work should only be conducted by authorised personnel . And it goes without saying that testing is performed during all stages . Manufacturers often cite RT , UT and visual inspection . Finished valves are hydrotested with kerosene , as HF could become corrosive in the presence of water .
Valves for alkylation – emissions
Again , no surprises to hear how much thought has gone into preventing fugitive emissions with dedicated containment solutions for the valve flanges as well as the stems . Many valve makers refer to the combined application of several features to prevent stem leakages , such as multiple-walled bellows , gland packings and back seats . As a further ‘ leak prevention ’ measure , a special colour coating is available for HF valves . Should any HF leak through a joint , on contact with the coating it will quickly trigger a colour change in the paint . This will alert on-site staff who can take immediate remedial action .
Unifying HF alkylation valves
In July 2023 , the Manufacturer ’ s Standardization Society ( MSS ) posted a ‘ call for action ’ to create a common standard for HF valves for alkylation plants . This read : “ In today ’ s rapidly evolving refining industry , standardization plays a crucial role in driving efficiency , cost-effectiveness , and safety . The Manufacturer ’ s Standardization Society recognizes the need for a unified standard for Hydrogen Fluoride ( HF ) Alkylation valves , as multiple refiners have implemented their own standards , leading to fragmented practices . This article explores the importance of establishing a single , universally accepted standard and the benefits it can unlock for the industry .” Info : https :// msshq . org / page / RAArticle
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