Patents by Inventor Norman C. Stewart

Norman C. Stewart has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4396488
    Abstract: A process for producing a superior coal liquefaction solvent. A particulate coal is admixed with a distillable aromatic hydrocarbon solvent and liquefied under predetermined conditions to form coal liquefaction products comprising distillable and substantially nondistillable soluble coal products and insoluble coal products. The distillable solvent and distillable soluble coal products are separated from the remaining liquefaction products. The remainder is admixed with a deashing solvent and separated under elevated temperature and pressure conditions in several separation zones into an insoluble coal products fraction, a light soluble coal products fraction and a heavy soluble coal products fraction. A portion of the light soluble coal products fraction is admixed with the recovered distillable solvent to form the coal liquefaction solvent. The light soluble coal products comprise at least about 15 percent and preferably 25 to 50 percent of the coal liquefaction solvent.
    Type: Grant
    Filed: October 8, 1981
    Date of Patent: August 2, 1983
    Assignee: Electric Power Research Institute, Inc.
    Inventors: Howard E. Lebowitz, Norman C. Stewart, William H. Weber
  • Patent number: 4191700
    Abstract: An economical, efficient process is provided employing coal, particularly subbituminous coal, as a fuel source for the production of distillate fuels, methanol, and methane. A hydroliquefier is operated under severe conditions to provide a high net yield of light distillates which are separated by distillation. The vacuum residue, which is produced above, is transferred as a slurry to a partial oxidation gasifier where synthesis gas is produced as feedstock for methanol or methane synthesis. Gaseous hydrocarbon contaminants are separated and used to generate additional synthesis gas, or to supply other fuel requirements. No net heavy distillates are taken as a product, being used as a fuel or converted to other products.
    Type: Grant
    Filed: August 2, 1978
    Date of Patent: March 4, 1980
    Assignee: Electric Power Research Institute, Inc.
    Inventors: Howard E. Lebowitz, Ronald H. Wolk, Seymour B. Alpert, Norman C. Stewart, William C. Rovesti
  • Patent number: 4111663
    Abstract: An improved reactor and method for use in solvent refining of coal, wherein the reactor is divided into a number of compartments and has an inlet port at the bottom thereof for receiving a mixture of a solvent, coal, recycle gas and hydrogen. The compartments in the reactor are defined by a plurality of vertically spaced, perforated plates, each plate having bubble caps in the perforations thereof to permit an upflow of the feed mixture in which reactions occur as the mixture passes sequentially through the various compartments and to form vapor zones below the plates. In one embodiment, a coolant from an external source is directed into the regions below at least certain of the plates to control the reaction temperature in the zone above the plates by cooling the feed to the next sequential zone. In another embodiment, a portion of the gas below each plate is removed from the housing, cooled and then returned to the compartment above the plate to cool the reaction therein.
    Type: Grant
    Filed: June 3, 1977
    Date of Patent: September 5, 1978
    Assignee: Electric Power Research Institute, Inc.
    Inventors: Ronald H. Wolk, Norman C. Stewart