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Hi all, We have problems with the performance of relief valves on site, the valves when taken to test bench in " as received" conition for pop test , they generally do not lift on the cold diff set pressure (within the tolerance) which then reduces the next run campaign of the relief valves. AS...

We know that 304L is the best choice for nitric acid environment due to oxidation issue involved with Mo, when you buy SS304L from the market, it comes with some percentace ( close to 0.03%) of Mo in the form of impuritiy. The questions I have 1. what is the max permissible Mo that can be...

ASME section VIII specifies acceptance criterion for cold differential test pressure of relief valve which is +/- 2.5%. Can this be applied to an API valve? or API has their own set of specifications on this?

ASME section VIII specifies acceptance criterion for cold differential test pressure of relief valve which is +/- 2.5%. Can this be applied to an API valve? or API has their own set of specifications on this.

We have an exchanger in Nitric acid plant, the channel of this exvhanger is parially made in Ti Gr 2 while rest of it is made with Ti Gr 12. We have been experience corrosion in the HAZ of G 12 Titanium and would like to understand the difference between these grades in terms of corrosion...

Hi, Recently I came across a very old WPS for welding alloy steel (ASTM A 335P22 to A 335P22). The WPS recommended use of argon back purge? Is that common to have back purge and what is the advantage of having it while welding. I am aware of back purge in stainless steel and risk of oxide...

Hi, We have a Den Exit fan installed in super phosphate plant, the impeller is made in SANICRO 28 and has a limited life due to very aggresive corrosive medium. It contains 1% Fluosilicic acid, and approx 0.2% hydrofluoric acid. Air temperature would be in the range of 40 - 55C. Can anyone...

Dear all, we had an incident of rotor seizure of syn gas compressor in ammonia plant. The compressor tripped on high vibration and came to halt very quickly, internal inspection inspection revealed that impellers and labys were all good on but inboard primay gas seal was damaged and found in...

We are replacing primary reformer tubes and its outlet pipe which is made in inconnel 800 HT is welded to existing 800 HT pigtail. I would like to know is it required to solution annealed the weld after repair and why. The existing inconel 800 HT pigtail is in service for more than 7 years and...

Hi I understand the requirement of pressure test / hydro test on inservice equipment are derated. Can any one help, which stardards define these guidelines ? cheers

We have a low temp CS pipeline carrying liquid ammonia at minus 33 Deg, these pipes were found with "lamination defects" which were considered to be acceptable from design view point. These defects were marked on the pipelines and need to be monitored for their growth on regular intervals form...

We have taken out a high temp H2 service U-tube exchagner for repair after two years of service. The weld between channel to nozzles made in F22 Cl3 have cracks in the welding as detected by TOFT. There are no apparent damages seen on nozzles or shell forging. We need to gouge out both nozzles...

Hi there, just wondering what is the right gasket design and material of constuction for 1200 Deg C application. This partucular one is on the reactor with 2200 MM dia. currently NEFALIT which is a refractory sheet is used as gasket, since it is used in pieces it is not very effective. The...

Hi, just wondering if anyone has come across a similar failure of centrifugal blower impeller where its shroud has cracked through and through from two places and all vanes are twisted. Please share your experience on such failure and elaborate bore stress which is the probable cause (excessive...

Dear all, What is the basic difference between SS 316 and 316L interms of their resistance against corrosion in seawater service. regards

Deal all, we have a problem of dry gas seal failure in syn gas compressor which operates at 160 KG dischrage pressure. For start up condition, to avoid contaminated gas flow from inside the machine to outside, sealing system provide a booser compresor which supplier high pressure N2 gas to...

Dear all, We have a 16" x 1500# butterlfy lug type valve, in lug type design, individual studs are fastened through both flanges to the valve body which has tapped screwed holes. Removal of valve from line requires removal of nuts and all studs from valve body and result in delays, one of the...

Hi all, Just wondering, is there any engineering standard for valves and fittings made of plastic and HDPE materials, for the pressure and physical dimensions? we have a system for hadnling chlorine, in absence of proper drawings/specification, its difficult to get the spare valves/fittings. regards

Any ideas or experiences of major crevice corrosion combine with minor pitting on the tube sheet face made in 254 SMO, especially on the gasket sitting areas, medium seawater at moderate temp of 40 deg C. could this be due to using gasket material having inconel 625 impregnation within? further...

Dear all, We all have been using the online sealing system for gas, steam and water line flanges, glands etc since ages. Do you have any experince of failure of studs/bolts while carrying out online sealing of a leaking flange. We had one incident where two studs of a 8" 600# flange joint...