3 replies to this topic

[grimster85]

All,

I am having an issue with a drain line from and analyser at (near) atmospheric pressure.
Originally the fluid was to drain to a process sewer, however the fluid is a heavy gasoil that will solidify at atmospheric conditions.

Unfortunately there are no lower pressure destinations to send it to so we are looking at alternative solutions. It has been suggested that we use a pump to get the oil into a nearby pipe. I am concerned that this will involve a significant ammount of extra time/money excetera and am looking for another solution.

I have come across pressure powered pumps for (steam) condensate removal before and note that the physics behind them should work for and liquid and equally for any pressurised gas. Therefore I looking to use one in this application.

Two problems that I can forsee result from the level control failing. One liquid overfilling coming out of the vent line (I think we can route it to the drain as a contingency). Two vapor blowing through the discharge (install a vapour trap)

My questions are the following:

Has anyone used a pressure powered pump in a non steam condensate application (with good results)
are there any problems that I have not thought of that may come into play.

[ankur2061]

grimster85,

I have successfully installed, commissioned and operated Pressure Powered Pumps (PPPs) in Dowtherm A (thermic fluid) vapor service handling condensate at 290-300 deg C. The PPPs that I found the most reliable were of Spirax Sarco make and the application was in DuPont technology Polyester plants where the entire process heating is done using saturated Dowtherm A vapor.

PPPs were used in the sections of the plant where the condensate pressure from the heated process equipment was lower than the pressure of the condensate collection tank and enough hydrostatic head was not available to overcome the pressure difference between the low-pressure process user and the higher-pressure condensate collection tank .

The important factor in ensuring the successful operation of a PPP is that the motive vapor pressure should be sufficiently more than the saturation pressure of the condensate. In our case the saturation pressure of Dowtherm A condensate at 290 deg C was 14 psig whereas the motive vapor at 337 deg C had a saturation pressure of 49.5 psig. This provided a sufficient driving force to drive the condensate to the condensate collection vessel.

Hope this helps.

Regards,
Ankur.

[grimster85]

Ankur,

Thanks very much for your help, it was exactly the type of information I was looking for. I believe that the concerns of liquid overfilling the condensate pot have trumped all the issues and we are looking into using an air powered diaphram pump.

[XENON-INC]

Hello,

My company Xenon Inc. makes such a pump, designed for that exact application. We are an Engineering Integration co. that designs and installs analytical systems(analyzers, shelters etc.) We ran into this dilemma so many times that we designed a sample recovery pump to address the problem. It is pressure driven and provides the analyzer with a constant atmospheric drain. When the discharge tank reaches capacity, the valving is actuated and the contents are discharged via pressurization with no interruption of the atmospheric accumulator. We have many different configurations available driven by application.

Please feel free to contact me if you would like more information.

www.xenoninc.com