Axens recommends that in cases of emergency depressurization of the reactor circuit, the circuit fluid is depressurized into the product stabilizer with the light gases still being treated in the off-gas caustic scrubber before being sent to flare.

Sulfuric acid alkylation units do not require the robust safety systems as the HF Alky units since sulfuric acid is a liquid at atmospheric conditions. The release mitigation safety systems typically used are curbed and/or diked areas to contain the liquid sulfuric acid in event of a leak.

The standard metallurgy for use throughout HF alkylation units is carbon steel. Showing a high degree of corrosion resistance in both low and very high acid concentrations, carbon steel is also useful for its relatively low cost compared to more exotic materials.

In the sulfuric acid alkylation process, droplets of acid are found in the effluent stream from the reactor. These droplets, which are formed primarily from the alkylation chemistry itself and the formation of intermediates, are small and stable and cannot be removed by gravity settling and / or coalescing alone.

What are some of your industry practices for upgrading gas plant piping to post weld heat treat to manage carbonate cracking risk?  Please comment on methods such as requirement for new piping, systematic replacement of existing piping, risk-based replacement, or inspection based?

Question 52: What strategies have you employed to profitably manage Tier III regulations (i.e., crude purchasing strategy, pre/post treating, FCC operational changes, sulfur reducing additives, etc.)?

What are some parameters that affect performance and reliability of FCC feed nozzles?  Can you describe any experiences with nozzle erosion inside the riser?  What about an external leak in the nozzle sleeve?

Localized regenerator afterburn is a common symptom of non-optimal air and/or spent catalyst distribution. Regional CO bed breakthrough will combust and afterburn in the regenerator dilute phase and cyclones indicating a stochiometric imbalance of air and coke. In a partial combustion operation, localized afterburn confirms confined oxygen breakthrough from the bed resulting in CO combustion in the dilute phase and cyclones.

What are your reliable methods to monitor expansion joint temperature?  Are some joints more critical than others?  What temperature range is acceptable?  How do you increase or decrease temperatures if they are out of the desired range?

The optimal level of carbon on regenerated catalyst (CRC) is often a balance between conversion and feed rate. Lowering CRC can be achieved by increasing air rate. In FCCs that are air blower or regenerator temperature limited, this can result in a feed rate reduction or residue processing reduction.