front_page Front page of site http://www.cheresources.com/invision Wed, 22 Feb 2012 22:33:43 +0000 180 Flow From Bottled Up Distillation Tower To Condenser - Natural Convect http://www.cheresources.com/invision/topic/14516-flow-from-bottled-up-distillation-tower-to-condenser-natural-convectioncondensation/
Maybe I am over-complicating this but thanks for any help you can provide.
Jamie]]> Wed, 22 Feb 2012 22:33:43 +0000 http://www.cheresources.com/invision/topic/14516-flow-from-bottled-up-distillation-tower-to-condenser-natural-convectioncondensation/ Longest Continuous Run Of Ldpe Autaoclave Plant http://www.cheresources.com/invision/topic/14512-longest-continuous-run-of-ldpe-autaoclave-plant/ our LDPE plant (auto clave) is running on stretch to reach 97 th day. It is the best ever acheived in india so far. Is it the longest run so far in the world for LDPE (autoclave) plant ? Wed, 22 Feb 2012 06:53:56 +0000 http://www.cheresources.com/invision/topic/14512-longest-continuous-run-of-ldpe-autaoclave-plant/ Centrifugal Pump Low Flow Protection http://www.cheresources.com/invision/topic/14511-centrifugal-pump-low-flow-protection/
Situation: centrifugal pump recirculates process oil continuously from / to tank. When tank must be emptied, a low pressure switch shuts the pump off when tank empties; one such switch continuously malfunctions, need other option to protect pump.

Question: what resources can you direct me to regarding other options, e.g., low amp drawn when pump runs dry...?

John]]> Wed, 22 Feb 2012 06:44:08 +0000 http://www.cheresources.com/invision/topic/14511-centrifugal-pump-low-flow-protection/ Neutralizing Agent For Acidic Liquid Waste http://www.cheresources.com/invision/topic/14507-neutralizing-agent-for-acidic-liquid-waste/ Dear all,

I am working on a project wherein we will have acidic liquid waste containing HCl of about 10% to as high as 23% [by wt]. We estimate the quantity of this liquid waste would be about 800 to 1000litres per batch [estimated batch time of about 24hrs].

I am wondering which neutralising agent will be the best in terms of safety, operation, environmental issues, price etc. I think the possible neutralizing agents are Na2CO3 solution, NaOH solution and CaO powder etc but don’t know which would the best one to choose i.e. if we use Na2CO3, it will generate CO2 gas etc.

I would appreciate any input.

Thanks,

]]> Tue, 21 Feb 2012 17:01:17 +0000 http://www.cheresources.com/invision/topic/14507-neutralizing-agent-for-acidic-liquid-waste/ Can Two Different Material (Ss304 And Ss316) Used In A Process http://www.cheresources.com/invision/topic/14502-can-two-different-material-ss304-and-ss316-used-in-a-process/
I am using SS316 for Dm water services. shall i use valves and strainer in SS304. Will there be any problem if i use two different materials.

Please advise.]]> Tue, 21 Feb 2012 06:42:52 +0000 http://www.cheresources.com/invision/topic/14502-can-two-different-material-ss304-and-ss316-used-in-a-process/ Looking For Assistance Verifying A Calculation Of A Gas Flow Across A http://www.cheresources.com/invision/topic/14499-looking-for-assistance-verifying-a-calculation-of-a-gas-flow-across-a-pcv/ I'm looking for some assistance regarding a calculation.
The gas flow rate across a PCV for a PSV sizing calc is what I'm having problems with. A high pressure vessel vents to a low pressure vessel through a PCV (details in spreadsheet). I've calculated 313Nm3/hr as the volumetric flow rate. However I've found some design documents, which while not kind enough to specify how they've reached this figure, indicate that it is to high. I should be getting an answer below 250Nm3/hr apparently.
If anyone might take a look at the attached spreadsheet and see if I have correctly calculated the flow rate across a Cv=4.4 Cg=156 valve from 550kPaa to 220kPaa for pure N2 service that would be greatly appreciated.
Thank you.

Attached Files

]]> Tue, 21 Feb 2012 04:45:01 +0000 http://www.cheresources.com/invision/topic/14499-looking-for-assistance-verifying-a-calculation-of-a-gas-flow-across-a-pcv/ Hot Utility Selection At Higher (Above 350C) Temperature http://www.cheresources.com/invision/topic/14496-hot-utility-selection-at-higher-above-350c-temperature/ I am working on to select the hot utility to heat up the process streams.....one of process stream need to be heated up from 300 to 370 C (4000kW) and the other from 640 to 658 C (3000kW).....My delta Tmin value for both streams is 10 C.......

We were discussing about which hot utility is less expensive as far as possible for both capital and operating cost is concerned (safety and operability also to be considered).....according to my view If i select a furnace (fuel:NG) than i can accommodate to heat up both the streams at respective temperatures mentioned above....( i am considering both the streams in different coils (tubes) in single furnace....)

some of my colleague also suggested to use thermic fluid at 370 C....ya its also good idea to avoid heating up of process stream into furnace coil (safety )

One of my colleague suggested that we can use the exhaust gas of gas turbine which is at 690 C......and can use gas exhaust to heat up the process streams in heat exchangers......I cant digest this Idea....The questions arise are following.......
1) Is this possible (practically and economically) to get a one fraction of stream from gas turbine exhaust which is upstream of HRSG.........
2) the area of heat exchanger (GT exhaust - process stream)? (I think it will be large)
3)reliability on gas turbine.....(if in case......gas turbine is down.? then...)

I will appreciate all of ur suggestions to select the hot utility at higher temperature.....

Thank you]]> Mon, 20 Feb 2012 21:21:48 +0000 http://www.cheresources.com/invision/topic/14496-hot-utility-selection-at-higher-above-350c-temperature/ Vertical Type Heat Exchager Querry http://www.cheresources.com/invision/topic/14486-vertical-type-heat-exchager-querry/
I have a polyester acrylate plant design project, and found the vertical type condenser installed on the top of the reactor(required to recycle the solvent ).
But, I don’t quite understand the reason why the vertical instead horizontal condenser to be installed. In spite of saving the limitation of space, is any idea for this kind of vertical type condenser to be chosen here ?

And, it seems that the solvent won’t boil out from the reactor cause the feed ,acrylic acid bp=141C is greater than water bp.= 100C, biphenol epoxy, bp=unspecified here.
So, could any pro here can kindly tell me why this condenser to be installed here to recycle the acrylic acid back ?


Thank you very much for your time and help.

Regards,

Attached Files

]]> Sun, 19 Feb 2012 12:54:33 +0000 http://www.cheresources.com/invision/topic/14486-vertical-type-heat-exchager-querry/ Water Cut http://www.cheresources.com/invision/topic/14477-water-cut/ what is the definition of water cut in oil reservoir]]> Fri, 17 Feb 2012 22:44:56 +0000 http://www.cheresources.com/invision/topic/14477-water-cut/ Pump Start Up With Empty Pipeline http://www.cheresources.com/invision/topic/14473-pump-start-up-with-empty-pipeline/
Would like to hear some advice on the following situation

We have a vertical turbine pump fitted with VFD and on the pump discharge line, there is a NRV followed by a manual hand valve. Intention is to slowly increase operating speed during pump startup so to slowly fill up the empty pipeline, with the hand valve completely open.

There are concerns that pump will reach run-out conditions (at the end of pump curve) while filling up the discharge line; causing motor overload & local pitting.

I understand that this is a major concern for starting pump without VFDs, but not sure if it applies to pumps starting at reduced speed. Any idea?

Many thanks!]]> Fri, 17 Feb 2012 10:43:16 +0000 http://www.cheresources.com/invision/topic/14473-pump-start-up-with-empty-pipeline/