Q & A > Question Details
I have a question about DeSOx Unit of RFCC
Our plant has a DeSOx unit that removes SOx and spent Cat’ (=dust) in Regenerator flue gas to meet environment standard.
After removing SOx and spent Cat’ by Mg(OH)2 solution, the waste water that includes suspended solid like spent cat’ is removed through filter press.
Filter press is dual type. When one is working, the other is stand-by. (Running time :18~30hr)
Because operation time of the two filter presses is not fixed and unknown, the cleaning man has to stay on or near the filter press to clean it, when switching.
So I want to ask:
1. How do you treat resulting waste water to meet environment regulation?
2. If you use filter press, what is the best way of managing it?
14/02/2014 A: David Kujawski, Refinery Water Engineering & Associates Inc, dk@refinerywater.net
Question 1: The first step is to quantitatively define the true operating design capacities of your existing wastewater plant. Keep in mind that these design capacities change daily. Next, deploy process control tools that enable you to instantaneously know the design capacities, and then to accurately calculate how much of that material can be added at that time to the wastwater plant.
Question 2: A V- Ring Press would be far superior to a Belt Press in this application. This investment would pay for itself quickly as there is no significant maintenance and no required routine machine Operator.
18/09/2011 A: Steven Kalota, ECI, steve@fluidcatcracker.com
Wet Gas Scrubber effluent water is normally routed directly to refinery Waste Water Treating where is undergoes standard biological treatment. I have no experience this water is treated differently or segregated from any other waste water streams in any other refinery with FCC WGS.
In regards to Filter management, Filter is typically rotated on high differential pressure. Experience will allow you to determine optimum pressure drop for switching for cleaning and Filter will have maximum design pressure drop as well. High and High-High alarms should be satisfactory to alert Operator of need for switching.
17/09/2011 A: Lindsay McRae, Pall Corporation, Lindsay_McRae@pall.com
Water should be neutralised of course prior to discharge. We have recent experience in middle east using 0.1um hollow fibre MF fitler system to treat effluent from a Belco wet scrubber for discharge into the sea. Pilot trials confirmed 0.1um MF filter can meet effluent spec of 20 ppmw for discharge into the sea (was previously >300 ppm TSS befoe treatment which did not meet 20 ppmw TSS discharge spec.).
If filtrate from filter press requires further treatment or polishing for TSS removal then a MF systm maybe able to deliver that. These are fully automatic with backwash / air scrub cycle operated by PLC automatically.