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Hi, I am planning to run some plastic piping to recycle storm water into our cooling tower (max pump pressure 120kPag). There is little cover in this area so the pipe will get sunlight for most of the day. I was wondering if anyone could advice about how well different products perform in...

We've been getting frequent blockages in our solids conveying eductor. It seems like the odd large particle is getting stuck in the venturi throat. What would the effect of increasing the venturi throat diameter (by about 20%) given the same motive gas nozzle size and pressure, and suction gas...

Hi, I looking at plan 53 for providing buffer fluid to a pump seal. One option for circulation of the buffer fluid is using a pumping ring. Could someone please tell me what a pumping ring is and how it works. Thanks, MarkkraM

We use the following estimate for failure to implement procedure or activity correctly. Ultimately we assume that no risk reduction can be claimed for operator intervention for a complex task required in an emergency situation. Note Pf = Probability of failure 1. NO STRESS (EG NORMAL...

As said earlier, the inefficiency of the pump will add heat energy to the fluid. Do calculations of the expected heat losses through the surface of your vessel at various water temperatures until you match the energy input from the pump. You may find that the water will not accumulate much...

Thanks for the reply quark. 5 bar refers to pressure just u/s of the barrels when tempered water flow has been established. Regards, MarkkraM P.S. Yes have previously heard of Mobius Strip http://scidiv.bcc.ctc.edu/Math/Mobius.html

I was wondering if someone could help me with the problem of steam hammering that occurs when we bring on tempered water to cool certain zones on our extruder. Background: While the extruder is not running, we introduce steam to these area's in order to keep them hot enough so residual...

Guidoo, I disagree with you here. I think it should be considered. I think the examples you gave were reason enough. "Of course, no electrical power can result in pumps/compressors/stirrers stopping. Therefore it can be a cause of no flow/higher temperature/lower pressure etc."

Can anyone give me a link to a good run down on the principles of cooling water treatment?

I've found a good HAZOP leader is the most important thing. They must be able to know when to move things along and know when it is important to focus an issues. Always cater for it as well!

Good explanation 25362, Thankyou

"So there should have been only ten minutes of operation of the exchanger with cold flow and no hot flow. Would that lead to cold embrittlement?" This is a question any process engineer should be able to work out given the flow and temperature of the fluid. What exactly was the oil's...

The pump curve for a centrifugal type pump gives a minimum required flow of 0.9 m3/hr using water as the test fluid. The fluid that I'm pumping has a specific gravity of 0.667, so does that mean my minimum required flow would be 600 kg/hr (0.9 m3/hr x 667 kg/m3) or do I need to maintain the mass...

ce51ha, I think other plants have had less issue than me. As Montemayor said, the re-generative adsorption dryer is the equipment of choice and I tend to agree. My dryers are quite old and did not have such a good maintenance thing going. One big problem we had once (when running only one dryer...

Thanks for all the replies. Yes I was aware of the difference between atmospheric dew point and pressure dew point and the principles of the absorption process. Our instrument air supplier have recently install a refrigeration type dryer so the quality of the air should be reasonably consistent...

Thanks Assumptions, Did some more research. Found a guidline recommending the dew point for IA should be 10degC lower than the minimum temp reached on the site. -70degC seems a little excessive if you are in a climate that never goes gets below 0degC. Is there any other driver for low dew...

I was wondering what a typical dew point people use for their insturment air? Do most plants go to the trouble (as we have) to use desicant dryers or do most simply use condensing type dryers? My plant had dryers to bring the air down to -60degC. We managed to stuff them up during our shutdown...

TD2K, Could you try that link again to the article and spreadsheet you mentioned. Otherwise is it OK to get a copy from you. Regards, MarkkraM

When checking my orifice calculation method (after reading denniskb's thread) I came across a statement saying that choked/critical flow does not occur accross thin, sharp edged, orifice plates. For chocking to occur the thickness of the orifice plate must exceed the orifice diameter. Is this...

Critical pressure drop is dependant on beta ratio and specific heat ratio. The actual DP will not change flow rate once past the critical ratio. I'm guessing this means that you should use the expansion factor determined at the critical pressure ratio for calculating flow?