Cutback periods

Using a burner with variable poc spin and with T-sensors at each end of a sidewall about 3 ft (0.95 m) above the ingot bottoms to control the heat pattern will reduce the cutback period to about 1 hr with 30" (0.76 m) square ingots. If an ingot is charged into a pit at 1800 F (982 C), it already contains 80% of the heat required to get to... 

Then, burner manufacturer North American Mfg. Company of Ohio produced a burner that controlled the temperature to 10°F (5.6°C) by a lot of spin or no spin (on/off control). The result was that the high-fire period was lengthened and the cutback period was reduced. A hot heat was ready in about 5 hr instead of 8 hr. Temperature measurements were taken with five thermocouples along the length of the pit bottom. When the pit temperature was thought to be uniform and the ingots ready to be rolled, the front-to-back temperature difference was 175°F (97°C). 

If the upward bias of aggregate forecasts over the period were estimated to be 5%, for example, the corresponding cutbacks relative to these forecasts would be about 25% and 10%, respectively. 

From 1967 through 1971 the unit operated with the fine catalyst. During this period the feed was West Texas sour vacuum bottoms cutback with 20% heavy cycle oil. In the last few months of operation with the fine catalyst, conversion of vacuum bottoms to distillate ranged from 55 to 75%, with 75-80% sulfur removal. The performance of the micro-spheroidal or fine catalyst was equivalent to the performance of the 1/32 inch extrudate. The unit capacity was expanded from 2500 to 6000 bbl/day. It was necessary to return to the extrudate catalyst at the higher feed rate to avoid excessive expansion of the catalyst bed. 

Closed Cup (CC). A method used to determine the flash point of fuels, solvents, and cutback asphalts, utilizing a covered container in which the test sample is heated and periodically exposed to a small flame introduced through a shuttered opening. The lowest temperature at which the vapors above the sample briefly ignite is the flash point. 

A utilities industry consultant predicts a cutback in the Canadian utilities industry during 2010-2015 by a percentage specified by a beta distribution with a = 1.5 and b = 2. Calculate the probability that Ontario Hydro will downsize by between 20% and 40% during the given 5-year period. 

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