| American Fuel & Petrochemical Manufacturers

Question 54: What are your best practices for soot blowing or scouring waste heat boiler tubes that ensure minimal impact to process variables, environmental limits are met, and spurious trips of safety instrumented functions on the ESP are avoided?

Automated systems are employed at Refineries that inject some type of abrasive (e.g., sand, walnut/pecan shells) on a scheduled interval basis. Injection duration must be controlled to ensure opacity limits are not exceeded. Manual injection of abrasives is also utilized.

Question 53: In the Third Stage Separator (TSS), what is the expected life of swirl tubes or cyclones assuming good performing regenerator cyclones? Of these two types, which handle upsets/ variable particulate loadings better?

The performance of swirl tubes is comparable with cyclones in terms of separation efficiency. Swirl tubes have distinct advantages over cyclones in being more compact, much easier to construct and have high mechanical integrity.

Question 52: What are your best practices for wet flue gas scrubber water supply and system monitoring (sampling frequency, instrumentation verification, etc.)? How do you handle the effluent water and any new emerging trends?

Water supply should be managed depending on the system design. The water source used by Motiva is clarified water. Due to the stainless-steel material and the chloride concentration in both the water and the caustic for neutralization the inlet duct temperature is monitored and controlled to prevent Chloride Stress Corrosion Cracking.

Question 51: For advanced (closed) riser termination systems, where does coke form inside the reactor vessel? What is the typical amount accumulated during a run?

The quantity of coke is heavily dependent on reactor technology, feed quality, and operating conditions. In earlier termination devices the riser outlet was open to the reactor. The vapors would spend a lot of time in the reactor resulting in coking.

Question 50: Butylene demand and prices in relation to other refined products reached a record level in 2017. What caused it and what can we do in the FCC to produce more butylenes?

Higher demand for butylene is result of octane shortage in the gasoline market stemming from several main causes.

Question 49: As the demand for higher octane gasoline components increases and lobbying for a 95 RON gasoline standard continues, how are you adjusting your operations to meet the market demand? What FCC specific changes do you make to produce higher octane gasoline components?

Refiners are optimizing their gasoline blend components to maximize high octane components. Alkylate and reformate yields are becoming increasingly important, as well as minimizing low octane component yields. The emergence of tight oil feeds has created an increase in low octane natural gasoline and LPG saturate production.

Question 48: What is the range of activity for FCC catalysts in the FCCUs? When is catalyst activity considered too low? When do you decide to reformulate versus changes in operating conditions in order to increase unit conversion?

BASF receives ECAT from about 200 FCC units worldwide. Of these, the ECAT activity ranges from 60-80, with approximately 75% of the units operating in the 70-76 activity range. The global average for 2017 was 72.5 and so far in 2018 the global average is 72.7.

Question 47: Are there any operational parameters that can be manipulated to improve the operation of the slurry circuit and minimize fouling? Can you outline the slurry exchanger circuit recommended design practices to minimize fouling, plugging and erosion?

Temperature: From experience, the rate of coke build-up increases greatly when the bottoms temperature is > 700F (370°C). It is recommended to maintain the bottoms temperature below 680°F (360°C) to be on the safe side.

Question 46: What is your strategy to minimize main fractionator bottoms (DCO/ Slurry) versus LCO production apart from feed quality/catalyst selection?

The primary operational handles to minimize bottoms production is optimization of the cat to oil in the R&R. As the C/O is increased more of the heavy oils will be converted. As with all good things in the FCC this can be taken too far. Limits can be reached on the actual operating equipment in this process.

Question 45: What are the safe and reliable options for rodding out plugged bleeders such as hydraulic ram pumps, packing gland / drill assemblies or tangential bleeders? How are these options used in a best practice for ensuring piping is hydrocarbon free and ready for maintenance?

Rod out tools or bleeder cleaners are safe and effective at clearing clogged drain, vent and instrument valves to be cleaned during normal operations. Most include some type of drill bit and local pressure gauge and are designed to handle high temperature and pressure applications.