Ash plus unconverted coal free basis

Corrected to ash plus unconverted coal free basis. b Assumed to be ash plus unconverted coal. ... 

The dimethylformamide (DMF)/xylene insolubles, assumed to represent ash and unconverted coal, were eliminated substantially. The benzene and heptane insolubles in the feed, adjusted to an ash plus unconverted coal free basis, were reduced substantially and the ASTM ash dropped from 4% to 0.1%. The SRC content of the filtrate, defined as percentage 850°F+ bottoms was 29%, as compared with 30.3% in the feed after correction to an ash plus unconverted coal basis. 

H-Coal hydroclone underflow was supplied by Hydrocarbon Research, Inc. It contained 9.09% ash and required filtration. Because of the relatively high viscosity of the stock, filtration was difficult, and only a limited amount of hydrotreater feed was prepared. Inspections are given in Table V. Thermal and atmospheric exposure during filtration downgraded the stock. The benzene and heptane insolubles in the product were substantially higher than those in the feed, when corrected to an ash plus unconverted coal free basis. The filtrate still contained 0.12% ash. 

Corrected to ash plus unconverted coal free basis. 

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