Recent content by chemdesign

My original question was to see if anyone had experiece with valve sizing in the specific application of rich caustic being letdown from a mercaptan extraction column. The existing valve is nearly wide open when sizing calcs indicate that it should not be. Note the valve is located right at...

The temperature of 250 F is due to 15 psig pressure.

Does anyone have any experience with the performnace of superduplex stainless steels (UNS S32760 or S32750) in caustic solutions (10% NaOH wt) with 1% - 5% sulfides wt. at temperatues around 250 F? Thanks.

Inlet pressure is 135 psig, outlet pressure is 80 psig, with 17 gpm flow. Valve Cv calculates to be 2.5, but actual Cv from % open in the field is more like 5.

TD2K, Thanks. i have tried talking to the licensors of caustic processes but have not had a warm response since this is not their process. i did verify the dowstream pressure via a pressure survey and am using that in the sizing equiation. i can't believe there is enough vaporization in this...

Does anyone have experiece with sizing the rich caustic level control valve on a mercaptan extractor in butane service? If so, can this valve be sized with the assumption that the vapor pressure of the rich caustic is very low which allows the actual valve pressure drop be used in the liquid...

I am aware of a general design guideline to limit the velocity of rich amine in carbon steel piping to 3 fps. Does anyone have an opinion on the max. allowable velocity in 316SS tubes in the rich/lean exchanger? Thanks.

Can anyone suggest the maximum tube length to shell diameter ratio that would make bundle handling difficult from the bundle being "too springy"? I have seen a number of 15:1, am wondering if anything higher is unreasonable. Thanks.

I am aware of a general design guideline to limit the velocity of rich amine in carbon steel piping to 3 fps. Does anyone have an opinion on the max. allowable velocity in 316SS tubes in the rich/lean exchanger? Thanks.

Does anyone have any experience with alloy selection for a boiling 10% wt. NaOH containing 3% Na2S? Temp. is 250 F and pressure is 10 psig. Normally we would use Monel for this application but are concerned with sulfides. Also considering Inconel 600 and Duplex SS (Alloy 2205). Thanks.

Can anyone explain the corrosion mechanism of Na2S to carbon steel in 200 - 250 F aqueous caustic solutions (10% wt. NaOH)? General guidelines in the GPSA manual indicate that Na2S in circulating caustic systems for RSH removal from LPG should be kept at 0.2% wt or less to reduce corrosion...

Can anyone explain the corrosion mechanism of Na2S to carbon steel in 200 - 250 F aqueous caustic solutions (10% wt. NaOH)? General guidelines in the GPSA manual indicate that Na2S in circulating caustic systems for RSH removal from LPG should be kept at 0.2% wt or less to reduce corrosion...

Can anyone explain the corrosion mechanism of N2S to carbon steel in 200 - 250 F aqueous caustic solutions (10% wt. NaOH)? General guidelines in the GPSA manual indicate that Na2S in circulating caustic systems for RSH removal from LPG should be kept at 0.2% wt or less to reduce corrosion, but...

we have had good luck with radar guages in this appliation, especially if the sump's contents (i.e. density) is variable.

Can anyone provide a reference for sizing flashing liquid control valves when the base liquid contains a significant amount of a dissolved gases, but the liquid itself (exclusive of the dissolved gases) is well below its bubble point? The traditional method outlined in the Fisher Catalog...