Heatrix performance
Heatrix performance
(OP)
Good Morning guys,
I'm wondering if you can help, As stated in my previous posts i'm trying to gain a little more process and mechanical knowledge whilst working in the hyrdrocarbon processing industry and I'v come across a problem that's got me confused.
We have a heat ex-changer that's over efficient, this creates a problem down stream as the temperature of the process gas coming out is to cold and is creating a knock effect further down stream. The process team have suggested that we drop the operating pressure of the cooling medium system thus increasing the temperature on the outlet of the heatrix. The mechanical issues are getting ironed in terms of valve replacements but this is there interim solution.
My issue is perhaps " simple" to you boffins but am I understanding that by dropping the pressure through the ex changer, i m actually decreasing the flow rate thus less heat transfer or is it connect to the boiling properties of the Cooling medium system when under pressure thus less heat transfer when pressure decreased.
I'm aware that this question is relatively simple in relation to the rest of questions on this site but I would really appreciate some advice or even a gentle push in the right direction.
Cheers
I'm wondering if you can help, As stated in my previous posts i'm trying to gain a little more process and mechanical knowledge whilst working in the hyrdrocarbon processing industry and I'v come across a problem that's got me confused.
We have a heat ex-changer that's over efficient, this creates a problem down stream as the temperature of the process gas coming out is to cold and is creating a knock effect further down stream. The process team have suggested that we drop the operating pressure of the cooling medium system thus increasing the temperature on the outlet of the heatrix. The mechanical issues are getting ironed in terms of valve replacements but this is there interim solution.
My issue is perhaps " simple" to you boffins but am I understanding that by dropping the pressure through the ex changer, i m actually decreasing the flow rate thus less heat transfer or is it connect to the boiling properties of the Cooling medium system when under pressure thus less heat transfer when pressure decreased.
I'm aware that this question is relatively simple in relation to the rest of questions on this site but I would really appreciate some advice or even a gentle push in the right direction.
Cheers





RE: Heatrix performance
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: Heatrix performance
Some more info would be useful.
However I can't see why you don't just throttle the cooling medium flow. This is a common control loop controlling flow based on downstream temperature.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Heatrix performance
Sincere apologies, I'm just getting my head around how best to work my questions.
Here are the facts, My cooling medium is 80 % demineralised water / 20% Teg mixture working in a system generally running at 5.8 barg. It normally runs through a heatrix and cools our discharge gas from a temperature of 170 degrees down to 45 degrees. Our Process team decided to drop the pressure down to 5.1 barg to see what affect it had on the cooling and it did actually work but they were then concerned with "flash boiling " of the cooling medium so we had to reinstate the original SP of the controller..
So they got the desired affect but No one ( out here ) can explain why this happened, and i have googled till i'm blue in the face.
Thanks
RE: Heatrix performance
It could be that the water did flash and create a pressure disturbance. A control valve downstream of the hx or a variable speed circulating pump will give you the controllability apparently missing.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Heatrix performance