Petroleum coking relates to processes for converting high boiling point, heavy petroleum feeds such as atmospheric and vacuum residua (“resid”) to petroleum coke (“coke”) and hydrocarbon products having atmospheric boiling points lower than the feed's. Some coking processes, such as delayed coking, are batch processes where the coke accumulates and is subsequently removed from a reactor vessel. In fluidized bed coking, for example fluid coking and FLEXICOKING (available from ExxonMobil Research and Engineering Co., Fairfax, Va.), lower boiling products are formed by the thermal decomposition of the feed at elevated reaction temperatures, typically about 900 to 1100° F. (about 480 to 590° C.) using heat supplied by fluidized coke particles.
Following coking, the lower boiling hydrocarbon products, such as coker gas oil, are separated in a separation region and conducted away from the process for storage or further processing. Frequently, the separated hydrocarbon products contain coke particles, particularly when fluidized bed coking is employed. Such coke particles may range in size upwards from submicron to several hundred microns, typically, submicron to about 50 μm. It is generally desirable to remove particles larger than about 25 μm to prevent fouling of downstream catalyst beds used for further processing. Filters, located downstream of the separation zone, are employed to remove coke from the products. Undesirably, solid hydrocarbonaceous particles present in the separated lower boiling hydrocarbon products may physically bind to each other and the filters, resulting in filter fouling, and, consequently, reduced filter throughput. There is an inability to effectively backwash fouled filters to remove foulant because the described foulant sticks to the filter. The accumulation of this sticky foulant reduces backwash effectiveness and thereby shortens the filter cycle, resulting in a lower yield of filtered gas oil.
There is therefore a need for a method for regenerating such filters to improve yield in petroleum coking product streams.
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