Why are two flow meters installed between the rich and lean amine liquid heat exchanger and the amine liquid regeneration tower?

FIQ is cumulative traffic. FIC is flow control

I mainly want to ask why it’s necessary to set FI or FIQ here; FIC is definitely needed to control the flow rate into the tower

This post was last edited by ylb913 on 2016-3-31 at 18:29. I understand this should be the requirement regarding the accuracy of the amine fluid flow rate. Due to the rise in the use of concentrated amine solution for regeneration, it has become difficult to find an appropriate denominator for calculating the energy consumption of the equipment; therefore, the amount of regenerated amine solution is used as the denominator. This increases the requirements regarding the accuracy of amine solution measurement. The reason for introducing FI or FIQ devices is likely this very factor – more accurate measuring instruments should be used. On the other hand, such measuring instruments sometimes have a higher failure rate, and maintenance of them can be quite challenging. For FIC devices, an orifice plate suffices; although its accuracy may not be as high, it operates more stably and is easier to maintain. Using FIQ is better than simply using FI, as it facilitates the calculation of monthly processing volumes; this can be done by subtracting the cumulative flow at the end of the period from the cumulative flow at the beginning of the period. However, even if Q is not taken into account in the design, it is simple to add a cumulative function to the flow meter via the DCS in practical applications.

Dude, do you guys also have FIQ and FIC?

This post was last edited by ylb913 on 2016-3-31 at 20:57. We are working with old equipment that is over 20 years old, and it has been continuously upgraded – from individual regeneration to centralized regeneration. The branches related to the amine solution process that were added later also came equipped with FIQs at both the inlet and outlet of the equipment; meanwhile, the user units also have FICs at the inlet and FIAs at the outlet of the equipment. In addition, there is also an increasing amount of materials related to various inlet and outlet devices; more flow meters with precise measurement capabilities are needed. Every year efforts are made to secure the necessary funding for this purpose, but so far the total amount invested has still been far from sufficient, and there are still many issues related to unclear accounting. The meters used in the inlet and outlet devices are related to matters such as material balance across the entire plant, as well as in various workshops and devices, energy consumption measurement, and processing losses. These meters have been optimized over the years, but the situation remains unclear, which causes a lot of frustration for everyone. It’s very difficult to secure the funds needed for repairs related to the renovation of old equipment; on the other hand, investing a little more in the installation of new equipment isn’t as noticeable. In my opinion, it’s better to have more sensors rather than fewer. Devices related to sulfur don’t receive much attention; indeed, we had very few instruments of that kind. A few years ago, there was a desulfurization tower for hydrogenation low-pressure gas, which was originally supposed to be part of the hydrogenation unit – its PID settings were also determined by that unit. In the end, however, it was installed in our workshop. It turned out that that tower had three thermal sensors at its top, middle, and bottom, and there was also a flow meter for the amine-rich liquid flowing out of it. We didn’t have any of these things here, and we never even thought we could have them. Then I wondered why they can have it while we can’t? With each additional indoor display instrument, there are more important parameters that can be traced, as indoor instruments keep records of trends, and it is only after related accidents occur that this information becomes known.

When we first started designing this, metering was installed for the rich amine liquid entering each branch; later on, only one metering device was kept on the main pipeline. It’s better to keep it this way now – having a clear reason makes it easier to explain things to other teams. Thanks, buddy