The CANMET Hydrocracking Process is a high conversion, high demetallizatlon, residuum hydrocracking process which, using an additive to inhibit coke formation, achieves conversion of high boiling point hydrocarbons into lighter products. Initially developed to upgrade tar sands bitumen and heavy oils of Canadian origin. an ongoing program of development (1,2) has broadened the technology to processing offshore heavy oils and the bottom of the barrel from so called conventional crudes.
This emerging technology showed a great deal of promise which was based largely on the relatively high conversion (90%) of the pitch (+975 °F) fraction. its basic simplicity, the absence of expensive catalysts, its demetallization ability and a number of other features. Following a comprehensive appraisal of the experimental data and economic potential in 1979, it was concluded that commercialization could be justified.
It is now generally known that a 5,000 BPD demonstration plant is in an advanced stage of construction at Petro-Canada's Montreal East refinery. The construction is on schedule and within budget with start up targetted for the third quarter of 1985.
Tar sands bitumen and heavy crudes were the first feedstocks to be investigated. Table 1 shows a partial list of heavy crude oil residues that have been processed, and items (4,5,6) of the references deal with this. CANMET Hydrocracking technology. in its continuous development, has been extended to processing the bottom of the barrel of conventional crudes. Table 2 shows some crude residues which have been tested in the bench scale and pilot plant facilities. Table 3 expands on the properties of two of these feedstocks, Light Arab Vacuum Bottoms. and Vacuum Bottoms from a Venezuelan blend of crude oil consisting of Mene Mota and Lago Treco crudes. These are low gravity streams consisting mostly of pitch with high amounts of sulphur, asphaltenes, and relatively high amounts of nitrogen and metals.
In the CANMET Hydrocracking Process a high degree of conversion of the pitch (+975 °F) is achieved producing hydrocarbons boiling below 975 °F. Although significant desulphurization (approximately 60%) and denitrogenation (approximately 40%) takes place, the emphasis of the process is on pitch conversion. As expected from a process which has a thermal cracking component. the products from the reactor do contain undesirable products such as diolefins in addition to the sulphur and nitrogen mentioned above. Because this is a hydro cracking process these products are preferable to corresponding coker prouucts. Nevertheless, downstream hydrotreating is a prerequisite for some of these fractions and such hydrotreating can readily be achieved in conventional plants with commercially available catalysts.
Table 4 shows the properties or two reformer feeds that are derived from hydro treating (C5-385 °F) CANNET naphtha. Both the sulphur and nitrogren are within the less than 1 ppm specification. The PONA analyses were determined by Gas Chromatograph - Mass Spectrometer (GC-HS) and Nuclear Magnetic Resonance (NMR) techniques (rather than the older FIA methods) and are therefore reported in weight percent. The analysis confirms the low olefin content as indicated by the Bromine number.