Patents Assigned to Northern States Power Company
  • Patent number: 5078752
    Abstract: An apparatus for the production of hot pressurized coal gas for use, for example, in power generation is provided. The apparatus includes a step of subjecting coal fuel to staged slagging combustion, to generate raw gas and liquid slag. The liquid slag is separated from the raw gas, and the raw gas is then subjected to a mixing and separation procedure, wherein it is treated and cleaned, for exampe of sulfur dioxide content. The raw gases may then be further treated and utilized to advantage in power generation. A preferred arrangement for conducting the process is also described.
    Type: Grant
    Filed: March 12, 1990
    Date of Patent: January 7, 1992
    Assignee: Northern States Power Company
    Inventors: Frank V. Mach, Peter P. Mach
  • Patent number: 5066325
    Abstract: A process and arrangement are provided for the efficient generation of energy from coal, while at the same time providing for a relatively inexpensive step in processing of iron or steel, and the extraction of valuable materials such as oils from coal. An advantage to the process is that relatively low quality coals can be utilized, since the coal is pretreated before any burning operation. Generally, the process involves three interacting stages. In the First Stage, a coal liquefaction/pyrolysis procedure is utilized to drive off volatiles, and form a very low volatile char. The volatiles can be collected and utilized as a valuable oil product, such as for diesel fuel or the like. The char material is preferably pelletized and utilized as a reductant, in a Second Stage of iron reduction and melting.
    Type: Grant
    Filed: February 24, 1989
    Date of Patent: November 19, 1991
    Assignee: Northern States Power Company
    Inventor: John M. Lehto
  • Patent number: 5064174
    Abstract: A process and arrangement are provided for the efficient generation of energy from coal, while at the same time providing for a relatively inexpensive step in processing of iron or steel, and the extraction of valuable materials such as oils from coal. An advantage to the process is that relatively low quality coals can be utilized, since the coal is pretreated before any burning operation. Generally, the process involves three interacting stages. In the First Stage, a coal liquefaction/pyrolysis procedure is utilized to drive off volatiles, and form a very low volatile char. The volatiles can be collected and utilized as a valuable oil product, such as for diesel fuel or the like. The char material is preferably pelletized and utilized as a reductant, in a Second Stage of iron reduction and melting.
    Type: Grant
    Filed: February 8, 1988
    Date of Patent: November 12, 1991
    Assignee: Northern States Power Company
    Inventors: John M. Lehto, Raymond L. Smith
  • Patent number: 5055131
    Abstract: A process and arrangement are provided for the efficient generation of energy from coal, while at the same time providing for a relatively inexpensive step in processing of iron or steel, and the extraction of valuable materials such as oils from coal. An advantage to the process is that relatively low quality coals can be utilized, since the coal is pretreated before any burning operation. Generally, the process involves three interacting stages. In the First Stage, a coal liquefaction/pyrolysis procedure is utilized to drive off volatiles, and form a very low volatile char. The volatiles can be collected and utilized as a valuable oil product, such as for diesel fuel or the like. The char material is preferably pelletized and utilized as a reductant, in a Second Stage of iron reduction and melting.
    Type: Grant
    Filed: October 16, 1989
    Date of Patent: October 8, 1991
    Assignee: Northern States Power Company
    Inventor: John M. Lehto
  • Patent number: 5045112
    Abstract: A process and arrangement are provided for the efficient generation of energy from coal, while at the same time providing for a relatively inexpensive step in processing of iron or steel, and the extraction of valuable materials such as oils from coal. An advantage to the process is that relatively low quality coals can be utilized, since the coal is pretreated before any burning operation. Generally, the process involves three interacting stages. In the First Stage, a coal liquefaction/pyrolysis procedure is utilized to drive off volatiles, and form a very low volatile char. The volatiles can be collected and utilized as a valuable oil product, such as for diesel fuel or the like. The char material is preferably pelletized and utilized as a reductant, in a Second Stage of iron reduction and melting.
    Type: Grant
    Filed: August 22, 1988
    Date of Patent: September 3, 1991
    Assignee: Northern States Power Company
    Inventor: John M. Lehto
  • Patent number: 5019360
    Abstract: A method for the processing of fly ash scrubber sludge or the like is provided. The method yields unique products, including a usable calcium silicate material and a high purity alumina material. The process involves a plurality of stages including a first magnetic separation in an acid leach. During the acid leach, valuable mineral components are converted into soluble sulfates. The leach residue, containing calcium materials, is extracted with ammonia solution to yield a desirable calcium silicate product. The leach liquor is treated in a preferred manner to precipitate relatively acid free aluminum sulfate. The aluminum sulfate is then converted into a desirable alumina product.
    Type: Grant
    Filed: June 8, 1990
    Date of Patent: May 28, 1991
    Assignee: Northern States Power Company
    Inventor: John M. Lehto
  • Patent number: 4986966
    Abstract: A scrubber module (16) of the wet type includes a partition (26) extending across the upper end of a tank (20) between the dirty flue gas inlet (28) and the clean flue gas outlet (30). The partition (26) takes the form of a plurality of hollow fingers (32), the zigzag lower edge of which is submerged in the aqueous absorbent (22). Oxygen-containing gas such as air is introduced into the lower end of the tank (20) as the partially cleaned flue gas from a baghouse or precipitator (76) is forced underneath the partition (26) at the upper end of the tank to facilitate oxidation and absorption of the sulfur dioxide into calcium sulfate in solution.
    Type: Grant
    Filed: August 1, 1989
    Date of Patent: January 22, 1991
    Assignee: Northern States Power Company
    Inventor: John M. Lehto
  • Patent number: 4861558
    Abstract: A scrubber module (16) of the wet type includes a partition (26) extending across the upper end of a tank (20) between the dirty flue gas inlet (28) and the clean flue gas outlet (30). The partition (26) takes the form of a plurality of hollow fingers (32), the zig-zag lower edge of which is submerged in the aqueous absorbent (22). Oxygen-containing gas such as air is introduced into the lower end of the tank (20) as the flue gas is forced underneath the partition (26) at the upper end of the tank without pre-cleaning of the flue gas to facilitate wetting and capture of the fly ash particulate as well as oxidation and absorption of the sulfur dioxide into calcium sulfate in solution, in the same vessel. A spray dryer and separator (84) is provided for removal of chloride in dry particulate form as calcium chloride before passage of the flue gas through the aqueous absorbent in the tank (20).
    Type: Grant
    Filed: October 6, 1988
    Date of Patent: August 29, 1989
    Assignee: Northern States Power Company
    Inventor: John M. Lehto
  • Patent number: 4853195
    Abstract: A scrubber module (16) of the wet type includes a partition (26) extending across the upper end of a tank (20) between the dirty flue gas inlet (28) and the clean flue gas outlet (30). The partition (26) takes the form of a plurality of hollow fingers (32), the zig-zag lower edge of which is submerged in the aqueous absorbent (22). Oxygen-containing gas such as air is introduced into the lower end of the tank (20) as the flue gas is forced underneath the partition (26) at the upper end of the tank without pre-cleaning of the flue gas to facilitate wetting and capture of the fly ash particulate as well as oxidation and adsorption of the sulfur dioxide into calcium sulfate in solution, in the same vessel.
    Type: Grant
    Filed: June 12, 1987
    Date of Patent: August 1, 1989
    Assignee: Northern States Power Company
    Inventor: John M. Lehto
  • Patent number: 4762686
    Abstract: A scrubber module (16) of the wet type includes a partition (26) extending across the upper end of a tank (20) between the dirty flue gas inlet (28) and the clean flue gas outlet (30). The partition (26) takes the form of a plurality of hollow fingers (32), the zig-zag lower edge of which is submerged in the aqueous absorbent (22). Oxygen-containing gas such as air is introduced into the lower end of the tank (20) as the flue gas is forced underneath the partition (26) at the upper end of the tank without pre-cleaning of the flue gas to facilitate wetting and capture of the fly ash particulate as well as oxidation and absorption of the sulfur dioxide into calcium sulfate in solution, in the same vessel.
    Type: Grant
    Filed: June 9, 1986
    Date of Patent: August 9, 1988
    Assignee: Northern States Power Company
    Inventor: John M. Lehto
  • Patent number: 4601430
    Abstract: An ash grinder (30) which is particularly adapted for reducing chunks of fly ash from a flue gas scrubber system to facilitate further handling, includes a rectangular throat section (32) of uniform cross-section with a shaft (52) extending therethrough. The shaft (52) is supported by bearings (54) on pedestals (56) located external to the throat section (32). Sets of perpendicular blades (66, 68) are secured to shaft (52) for rotation between opposite sets of fixed blades (48) located inside the throat section (32). The shaft (52) is driven by a reversible motor (76) through a chain and sprocket arrangement (70, 72 and 74) at a relatively slow speed on a continuous basis so that any large chunks of fly ash formed within the scrubber chamber, such as during a system upset for example, will be reduced to an acceptably smaller size to facilitate further handling without manual intervention or interruption of system operation.
    Type: Grant
    Filed: May 10, 1984
    Date of Patent: July 22, 1986
    Assignee: Northern States Power Company
    Inventor: Michael F. Skinner