Back

Question

Submit an Answer

Lean amine mechanical filters plug very often like 2 times per day. In our unit mechanical filters are located before lean amine coolers, but in other designs filters are located at the cold side. We also suspect that problem is due to corrosion in the regenerator overhead lines, but corrosion coupons show that corrosion speed is low.

What can be the reason for such filter problem?

Mar-2022

Answers

Nagarathinam S Murthy, McKinsey & Company, Chennai, nssvdvr@gmail.com

The cleaning frequency of amine mechanical filter is rather unusual unless the circulating amine is awfully 'dirty' implying low on pH, high of HSAS, high on TSS loading, with frequent carryover of HC and amine loss. Pl look into the following as part of the root cause evaluation.

1. Acid loading in rich amine.

2. Rich amine velocity in process piping and temperature at each absorption tower exit.

3. Quality of antifoam being used and its compatibility with amine system.

4. Excessive ingress of Oxygen and inorganic acids into amine system. It could be due to change of catalysts in u/s FCC and reduced cycle time in Coker respectively.

5. Degradation of amine at regenerator reboiler due to higher FFT (fluid film temp)

Approach Suez representative in your area to take a holistic view of the current issue. Best of luck to get circulating amine as water white in colour with 'right' quality wrt pH, % strength, colour, Impurities presence, foam test, etc.

Mar-2022
Chris Wallace, Filtration Technology Corporation (FTC), cwallace@ftc-houston.com

Amail, the general target flux rate for a pleated cartridge filter in an amine system (fluid with water-like properties, specifically density and viscosity) is 0.5 gallons per minute / square foot.

I am surprised to hear you have 316SS cartridge elements in your amine system. This is not common in these systems, But we have run across them. Typically, they are cleanable and not replaceable due to the cost. There are much more economical options that can provide better filtration performance (improved efficiency, surface area, and life).

I will reach out to you directly to find out more details with the hope of guiding you to a solution to your problem. Of course, improving filtration performance is only one part of the solution. Identifying the source of the contaminant is another.

Mar-2022
Amail Mamedova, STAR Refinery, amail.mamedova@socar.com.tr

Thank you for your answer. We use replaceable cartridge filters and filter element is made from 316L SS.

What is the optimum range for flux/surface area?

Mar-2022
Chris Wallace, Filtration Technology Corporation (FTC), cwallace@ftc-houston.com

As you are aware, solids can form in the regenerator even if you have good rich amine filtration. I recommend reading "Iron Sulphides - Friend or Foe?" by Spooner & Sheilan (Amine Experts).

Filters are a great tool to monitor your system. They can tell you if something in the process has changed. But, it takes a lot of information to identify what is causing your increased change-outs.

A short list of things to consider as a start....

Run total suspended solids (TSS) via gravimetric analysis method on your amine. Take rich samples, pre-and post filters, and compare to lean samples pre and post filters. See if lean inlet has higher TSS than rich outlet.

I would also evaluate the hydrocarbon content. What type of filters are you using? If cartridges with polypropyelene media, you could have hydrocarbon cause pre-mature fouling. If you are on the hot side, then you are likely not using polypro.

Are you filters properly sized? Do you have an appropriate media flux rate (flow rate / surface area)? Have you changed suppliers recently? Have you inspected your filters to compare previous change-outs to the current change-out? What is fouling the media?

Are you suddenly getting a shoe polish type contaminant? If so, have your bicine or HSS levels changed.

Silicone based anti-foams will foul filters. The silicone will be stripped out with a 20 micron or lower absolute rated filter medium. This will increase the media differential pressure.

Mar-2022