control valve trim for wet steam 3

[bingbingwang]

thread408-293925
I got a related question about the control valve trims for wet steam service.
process conditions:
95% steam quaulity, 25000kg/h flow@ max, 7800kpag@296 C for design, operating 20000kg/hr@5520kpag@271 C.
this is a flow control valve, globe (hopefully equal%), any suggestions on valve trim selection, considering material, wet steam erosion, and noise control?

thanks.

 

[bingbingwang]

forgot the pressure drop for this valve:
500kpa @min@4000kg/h, 2271kpa-d@normal@20000kg/h, 1700kpa-d @ max@23850kg/h
thanks folks.

 

[SNORGY]

You might contact Willis or MasterFlo, but I think the status quo for quite a while was stellite.

 

[bingbingwang]

stellite is quite good for the stem, but I guess it is way too expensive for cage and plug. any more suggestions?

 

[TD2K]

I'll have to check with a couple of people, that's just a nasty set of conditions when you mix liquids in with it.

 

[TD2K]

I talked to my insrument engineer. For those conditions, you will want everything at least stellite coated. It's expensive but you have a severe service valve there. You can also try the standard control valve companies (Fisher, Masoneilan, Valtex) and see what they suggest but I don't think it's going to be cheap.

 

[rmw]

Try Copes Vulcan and Leslie too, they were good at this, especially Copes Vulcan. I think they are part of DeZurik now.

rmw

 

[gerhardl]

From your posting it is obvious that cost (as it always is) is an issue. For this application trying to saves money on material and valve construction details might cost you more than you like in the long run....!

Suggest you also check Gestra as brand (Flowserve?).

 

[bingbingwang]

thanks for all the comments above.
this application is typically steam injection on the oil sand offsite pads (SAGD process). the quality of the steam is always nasty for the control valve. some control valves like FISHER/w whisper I trim has been found cut off by erosion-corrosion which may co-happen with flashing of the condensate on the cage. i do not know how to paste the photoes of the damaged trim, it is really a mess, you can see the 17-4PH 1150HT hardened cage was cut off with a big gap, looks like a knife cut a piece of wood. for sure, it is severe service. if you have more ideas about the metals of the cage and/or trim styles , please feel free to make a sound here. ...

Get help and return with helps!!.

 

[rmw]

When one has a wear situation where the fact that wear is going to occur and cannot be mitigated, then the decision is to pick the componentry so that the wear is where you want it not where it is determined by something outside your control. Said differently, you need to pick a cage/trim system such that the wear is in the least costly, most easily replaced piece(s) of the valve rather than suffering wear in some part of the valve that renders the valve useless for future use.

rmw

 

[gerhardl]

An experienced steam engineer will always be able to tell you if wear is caused by abrasion (more or less polished surfaces) or if it is caused by cavitation (pitted surfaces). Cut with knife = combination of both and material weakened by cavitation and breaking off?

I suggest that you have a look of pipeline layout and steamtrap and reduction station placement and layout.

Why wet steam? Is this necessary or unavoidable? rmws' last posting points to important details for the valve selection. If cavitation is the problem a correct valve size (valve selected to large and giving a too limited opening by normal operating conditions ?) and valve trim with 'steps'(rmw posting) might give improvement.

 

[bingbingwang]

Thanks, Gerhardl,
I have given you a star on this answer. . I guess the cut-off was caused by erosion-corrosion on the cage. FISHER whisper I trim has to be flow-up, which means the flashing or cavatation (caused by water droplets?) on the cage. maybe it will be better if i change it to ET valve with flow down direction which will move the flashing and cavitation to the seat ring therefore protect the cage. the seat ring is a CoCr-A hardened face 316sst, do you think this is gonna work for wet steam?
rmw, I have to take the cost into consideration, client needs hundred this steam control valves for their injection wells.it is not only for one valve.

really appreciate both of you.


Get help and return with helps!!.

 

[TD2K]

"client needs hundred this steam control valves for their injection wells.it is not only for one valve"


Some valve company is going to be very, very happy