The American Fuel & Petrochemical Manufacturers (AFPM) has announced the winners of the 2021 Annual Safety Awards, part of the refining and petrochemical industries’ ongoing mission to enhance and recognize outstanding workplace safety. The awards, considered the industries’ premier awards, are part of a comprehensive program developed by the AFPM Safety and Health Committee to promote safe operations in the refining and petrochemical industries. They also recognize facilities that have outstanding occupational and process safety performance.
Question 61: Have you found that you needed to install a methanator upstream of a chlorided catalyst isomerization unit to remove carbon monoxide (CO) from the feed? What is the source of the CO and how much of a difference has the addition of the methanator made to catalyst life? What is the expected payout for the cost of the methanator?
The problem now comes from the oxygen ingress coming in with makeup hydrogen, with the culprit typically being CO and CO2.
Question 60: How do you detect leaks in an isomerization unit's steam charge heater? Have you been able to detect a leak before a significant portion of the catalyst bed was deactivated?
The common problem in these units is deactivation of the catalyst by the ingress of water over the catalyst, because water actually deactivates the catalyst. This is a slide of a typical flow scheme for these units, and kind of shows you the conundrum of designing and operating these units.
Question 59: For a hydrofluoric acid (HF) alkylation unit, what instrumentation do you recommend for controlling HF acid levels throughout the unit?
Generally speaking, the industry is moving more and more toward using nuclear devices for level of protection. At PRSI, we have a major project in place now where we’re identifying crucial areas in our units and are installing nuclear devices in both of our alkylation units.
Question 51: Reforming unit stabilizer column top trays and overhead condensers can experience fouling with ammonium chloride salts, which are commonly removed by online water washing of the column overhead. What practices do you employ to reduce the risk of rapid corrosion and the potential failure associated with this fouling and subsequent water washing procedure?
Ammonium chloride salts are a common problem in both naphtha reforming and naphtha hydrotreating units.
Question 50: What is the proper firefighting media to use when putting out a fire when both spent sulfuric acid and heavy hydrocarbon are present (e.g., in a spent acid tank or a diked area that has a layer of hydrocarbon floating on the spent acid)?
The water and acid will interact, which makes water a poor choice. Most of the foams of which we are aware are mostly water. A dry chemical will also react to the acid. So, as always, when you get into a fire situation, there’s some initial assessment that’s required of the fire.
Question 49: In the past year, a sulfuric alkylation unit released a significant amount of sulfur dioxide to atmosphere when light hydrocarbon flowed from the reaction zone through the acid blowdown system and into the spent acid tank. What measures do you recommend for preventing this?
We would recommend ensuring that the acid knockout drum be sized large enough to allow the hydrocarbons to disengage in the drum.
Question 22: With the introduction of modern riser termination devices (RTDs) and the advent of severe FCC feed hydrotreating, what is your experience (typical values) with the ash content of the main fractionator bottoms (MFB) product? Please describe the testing methodology utilized and the recommended testing frequency for this stream. What process, practices, and/or equipment changes can be employed to reduce the ash content of the MFB product?
Sunoco’s FCCs operate primarily in resid cracking mode; either atmospheric or vacuum resid, typically without the benefit of upstream feed hydrotreating. We have FCCs with coupled two-stage riser termination devices, riser cyclones uncoupled to the secondaries, and simple RTDs followed by either single- or two-stage cyclones.