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US 5,863,389 AGranted
Pulp bleaching reactor for dispersing high consistency pulp into a gaseous bleaching agent containing ozone
AssigneeUnion Camp Patent Holding, Inc.
InventorsDavid E. White, Michael A. Pikulin, Thomas P. Gandck, William H. Friend
Life of this patent
Estimating the term…
Abstract
An apparatus for delignifying and bleaching a lignocellulosic pulp without the use of elemental chlorine. The bleaching reactor is a horizontal vessel having a central rotatable shaft which preferably contains paddles, cut and folded screw flights or a ribbon flight, to disperse and advance the pulp particles in a plug flow manner while contacting and mixing the pulp particles with a gaseous bleaching agent such as ozone for substantially uniform bleaching thereof.
Claims23
An apparatus for dispersing high consistency pulp particles into a gaseous bleaching agent comprising:
- a shell;
- means for providing high consistency pulp particles having a consistency of at least about 20%, said providing means operatively associated with means for introducing the high consistency pulp particles into the shell;
- means for generating a gaseous bleaching agent that contains ozone, said generating means operatively associated with means for introducing said gaseous bleaching agent into the shell;
- and
- means for conveying the pulp particles through the shell at a certain conveying speed and certain conveying efficiency, the conveying means comprising:
- means for reducing the certain conveying efficiency of the conveying means, including dispersing means for intimately contacting and mixing the pulp particles and the gaseous bleaching agent by simultaneously exposing substantially all surfaces of a majority of the pulp particles to the gaseous bleaching agent as the gaseous bleaching agent flows and surrounds the pulp particles to allow approximately equal access of the gaseous bleaching agent to the pulp particles by lifting, displacing and tossing the pulp particles in a radial direction to disperse the pulp particles and suspend at least a portion of the pulp particles in the gaseous bleaching agent while the dispersed and exposed pulp particles advance through the shell in an axial direction;
- and
- means for increasing the certain conveying speed of the conveying means operatively associated with the dispersing means to provide a predetermined fill level of at least 10% of the pulp particles in the shell and to advance the dispersed pulp particles through the shell in a plug-flow like manner at a dispersion index of less than 8.
5 more elements
An apparatus for dispersing high consistency pulp particles into a gaseous bleaching agent comprising:
- a shell;
- means for providing high consistency pulp particles having a consistency of at least about 20%, said providing means operatively associated with means for introducing the high consistency pulp particles into the shell;
- means for generating a gaseous bleaching agent that contains ozone, said generating means operatively associated with means for introducing said gaseous bleaching agent into the shell;
- particle conveying means for conveying the pulp particles through the shell at a certain conveying speed and certain conveying efficiency while providing a predetermined fill level of at least 10% of the pulp particles in the shell, the particle conveying means comprising:
- means for reducing the certain conveying efficiency, including dispersing means for intimately contacting and mixing the pulp particles and the gaseous bleaching agent by simultaneously exposing substantially all surfaces of a majority of the pulp particles to the gaseous bleaching agent as the gaseous bleaching agent flows and surrounds the pulp particles to allow approximately equal access of the gaseous bleaching agent to the pulp particles by lifting, displacing and tossing the pulp particles in a radial direction to disperse the pulp particles and suspend at least a portion of the pulp particles in the gaseous bleaching agent while the dispersed and exposed pulp particles advance through the shell in an axial direction;
- and
- means for increasing the certain conveying speed in combination and operatively associated with the means for reducing the conveying efficiency to advance the dispersed pulp particles through the shell in a plug-flow like manner at a dispersion index of less than about 8 at the predetermined fill level.
4 more elements
An apparatus for dispersing high consistency pulp particles into a gaseous bleaching agent comprising:
- a shell including a particle introduction zone, a particle fill level providing zone, at least one particle/gaseous bleaching agent mixing zone, and a particle exit zone;
- means for providing high consistency pulp particles having a consistency of at least about 20%, said providing means operatively associated with means for introducing the high consistency pulp particles into the particle introduction zone of the shell;
- means for generating a gaseous bleaching agent that contains ozone, said generating means operatively associated with means for introducing said gaseous bleaching agent into the shell;
- conveying means for conveying the pulp particles through the shell at a certain conveying speed and pertain conveying efficiency, the conveying means comprising:
- means for providing a predetermined fill level of at least about 10% the high consistency pulp particles in the shell, said fill providing means located in the particle fill level providing zone of the shell;
- dispersing means for intimately contacting and mixing the pulp particles and the gaseous bleaching agent by simultaneously exposing substantially all surfaces of a majority of the pulp particles to the gaseous bleaching agent as the gaseous bleaching agent flows and surrounds the pulp particles to allow approximately equal access of the gaseous bleaching agent to the pulp particles by lifting, displacing and tossing the pulp particles in a radial direction while the dispersed and exposed pulp particles advance through the shell in an axial direction;
- and
- means for increasing the certain conveying speed in combination and operatively associated with means for reducing the certain conveying efficiency to advance the dispersed pulp particles through the shell in a plug-flow like manner at a dispersion index of less than about 8 at the predetermined fill level;
- and
- means for removing the pulp particles from the particle exit zone of the shell.
7 more elements
The apparatus of claim 6 wherein the shell includes first and second shell sections, with the first shell section including the particle introduction zone, the particle fill level providing zone and a first pulp particle/bleaching agent reaction zone, with the second shell section including a second pulp particle/bleaching agent reaction zone and the particle exit zone.
Dependencies are inferred from the claim text.