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Thanks for your answers. They confirm my assumption that the valves used in the past are unsuitable for this application. I will set up a basic specification and inquire a valve fromt he proposed suppliers. BR

Hi, I have the special situation that our boiler drum blowdown valve starts leaking after a view open / close operations. I have inquired various valve manufacturers and we even tried different hardfacings, etc. but none of the valves work for a sufficient time. Now it is the used valve type...

Thx, their website is also a very good resource. BR

Dear all, we are facing problems with proper condensate removal in "old" steam distribution piping. I was wondering whether there is good literature available describing this topic especially at which distance to put steam traps, start up dewatering devices, slopes, etc. and how to maintain the...

Hi, I am currently struggling to work out a "hot spot evaluation procedure". We frequently face the problem of hot spots on pressure vessels with refractory lining. Without an obvious reason a hot spot may arise during operation which in the worst case forces a plant shutdown. I was informed...

Thanks for your Infos. I am checking your references and I find that process conditions are highly influencing the corrosion behaviour in this environment. Nevertheless there are no reports on failures as we experienced them. The location in the process is in the "Lean" section where there is a...

Yes. It is the seat of a ball valve. The method of application was HVOF (high velocity Oxygen fuel coating - Thermal spray). The ball was coated with Chromium Carbide which showed better resistance. The Nickel hardfacing turned "Black". It was a very weird failure. We are now concerned that...

Hi, we have a CO2 Absorbing plant in Operation which uses "Benfield" lye as absorbant. Most parts of the System are made of Carbon steel. Nevertheless, we face some Problems with the few parts made of Nickelalloy and Chromium Carbide. The Nickel alloy was completely desolved after 1y Service...

Hi, we are currently facing problems with valves in a Benfield solution line. We are using ball valves (Class 900, 6"). The ball valves are made of stainless steel (316L) with the ball and the seat being hardened with Chromium Carbide. It seems like the Chroumium Carbide hardfacing is...

Unfortunately I was not involved when the valve was purchased. The supplier told me they never faced this Problem before (but that's their Standard answer). In fact, every valve of above construction gets stuck within a few actuations when used at -40°C. I wonder whether this valve would Show...

Hi, I am currently facing some problems with below sealed globe valves used in cryogenic service (down to -40°C). After only two to three actuations, the spindle gets stuck to the plug in the area where the rotational is tranlated to a linear movement. We have around 14bar in the system and...

I would also suggest to go with Incoloy buttering and weld the 304L nozzle after PWHT. For hydrogen service you should go with full penetration welds. Performing PWHT with the nozzles welded should be prevented since your vessel will be subject to temperatures of about 600-700°C for some hours...

@Danlap: That looks very similar to our catalyst dust! Was that valve leaking as well? I will contact above mentioned suppliers to get some quotes as well as their idea on the issue. Is there anything like "seat cleaning" (e.g. with pressurized air) before the valve closes to "blow away" any...

Thanks for your replies. Operations department informed me that the catalyst dust accumulates in the piping of the purge line (Valves are usually only opened once a year). When the valve is opened, the accumulated dust is flushed with the gas stream to the atmosphere. It is almost impossible to...

Hello, I am in search for a manufacturer for On/Off valves for syngas service for a Syngas purging line. Design conditions: Pressure: 190bar (to atmosphere) Temperature: -33°C/50°C Size: DN50 or DN80 Housing material: Carbon steel We have traces of catalyst in the purge gas which is a very...

Hy, I am just trying to figure out what happens to the metal grain structure of A/SA516 - Grade 60 material when it is temporary heated to 500°C for lets say 5h and then cooled to ambient temperature during operation of a pressure vessel. Will the material be subjet to embrittlement or creep...

Thanks a lot. Dan

Thanks a lot. Dan

Thanks for your reply and useful input. Do you know if there are some studies available for toughness and strength of such repair welds? BR, Daniel

Hello, I like to adress this post to all collegues who are involved with steels at elevated temperatures like boilers, coloums, etc. I am working on a very special case where the chamber of a heat exchanger made of 1.7380 (apprx. ASTM 217-WC9) was found to have a crack. The codes (EN as well...