US PATENT SUBCLASS 208 / 408
.~.~ Gas includes hydrogen

Current as of: June, 1999
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208 /   HD   MINERAL OILS: PROCESSES AND PRODUCTS

400  DF  BY TREATMENT OF SOLID MINERAL, E.G., COAL LIQUEFACTION, ETC. {13}
407  DF  .~ Specified agitation or circulation in gas contact zone {3}
408.~.~ Gas includes hydrogen

DEFINITION

Classification: 208/408

Gas includes hydrogen:

(under subclass 407) Subject matter wherein a gas containing elemental hydrogen, added to the process, is present in the gas contact zone.

(1) Note. The presence of hydrogen gas normally produced during retorting operation is not sufficient fo replacement of a patent in this subclass.