Q&A

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(2015) Question 88: Describe your approach to repair and improvement (i.e., materials, design, installation, and anchors) to areas that have seen repeated refractory failures.

Speaking of the improper refractory repair, especially in a hot-wall refractory with the coking service, low alloy base metal requires a 300°F preheat along with removal of all sulfides on the metal surface. If you do not do this, you will get weak and brittle welds that will crack easily because of their low weld strength. And therefore, your anchors will break off and your refractory will fail due to the coke growth behind the refractory.

(2015) Question 89: For an equipment revamp/replacement, what are the factors you consider when choosing between hot-wall and cold-wall refractory design, including advantages and disadvantages of each?

Shell has experience with both cold-wall and hot-wall refractory designs for reactors and stripper vessels, but regenerator vessels are always cold-wall refractory designs. Depending on the reactor and stripper vessel, refractory type and standpipes, liftpots, and external portions of the riser can be either cold-wall or hot-wall designs.

(2015) Question 90: We are planning to purchase a new flue gas steam generator. What is your preferred configuration? What are the critical operating parameters you employ to ensure reliable operation? What is your sparing philosophy?

The configuration of the flue gas steam generator will be predominantly governed by FCC design. For a partial-combustion unit, it will be a CO boiler or a CO incinerator cum FGC (flue gas cooler) combination. For complete combustion, it will be a FGC or waste heat boiler alone. By CO boiler, typically we mean a boiler where the steam generating tubes are exposed to direct flame.

(2015) Question 91: What are your top three causes of unit slowdowns, and what is the loss in onstream factor for each? Please provide the same information for your top three causes of unit shutdowns.

FCC/RFCC units are the one of the major secondary units in almost all of IOCL’s refineries. Irrespective of demand positions, these units are always required to operate at high capacities. All of our refineries had been participating in the benchmarking surveys conducted by Solomon Associates, and the results comparing IOCL FCC units with rest of the world (2014 study) are indicated below.

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Q&A

(2015) Question 88: Describe your approach to repair and improvement (i.e., materials, design, installation, and anchors) to areas that have seen repeated refractory failures.

(2015) Question 89: For an equipment revamp/replacement, what are the factors you consider when choosing between hot-wall and cold-wall refractory design, including advantages and disadvantages of each?

(2015) Question 90: We are planning to purchase a new flue gas steam generator. What is your preferred configuration? What are the critical operating parameters you employ to ensure reliable operation? What is your sparing philosophy?

(2015) Question 91: What are your top three causes of unit slowdowns, and what is the loss in onstream factor for each? Please provide the same information for your top three causes of unit shutdowns.