Rotating pulp bleaching reactor having inner and outer shells and lifting means on the interior surface of the inner shell

A bleaching apparatus for bleaching lignin containing pulp particles comprising:

• a) an inner tubular shell member having a tubular wall with an input end and an output end at opposite ends of the axial length of the tubular wall, said inner shell member having an internal wall surface defining a free, open reaction zone bounded thereby;
• b) an outer tubular shell member having a tubular wall with an input end and an output end at opposite ends of the axial length of the tubular wall, said outer shell member being disposed in surrounding relation with respect to the inner shell member to provide a space therebetween and with the input and output ends of the outer shell member located adjacent and spaced axially beyond the input and output ends of the inner shell member;
• c) pulp feed conduit means extending from a location communicating with the exterior of the outer shell member and extending through the input end of both shell members for feeding pulp particles into the inner shell member;
• d) an output opening at the output end of each shell member for removing pulp particles from both shell members after passing through the reaction zone of the inner shell member,
• i) the output end of the inner shell member being open across its diameter to define the output opening of the inner shell member, and
• ii) the output opening of the outer shell member being located on the tubular wall thereof at a position axially beyond the inner shell member and facing downwardly therefrom;
• e) means for rotatably supporting the inner shell member on the inner wall surface of tubular wall of the outer shell member;
• f) rotating means for rotating said inner shell member about its axial length;
• g) means for introducing an ozone containing gaseous bleaching agent into the reaction zone of said inner shell member in an amount sufficient to bleach the pulp particles in said reaction zone;
• h) lifting means mounted on the interior wall surface of said inner shell member for contacting the pulp particles fed into the input end of the inner shell member, and directing them into the reaction zone for mixing and reacting with said gaseous bleaching agent as the inner shell member is rotated, said lifting means including a plurality of circumferentially spaced fixed blade members extending axially and slightly spirally along the axial length of the inner shell member;
• i) tilting means for positioning the output end of the inner shell member at a level sufficiently lower than its input end to cause the pulp particles to move toward the output end as the inner shell member is rotated;
• j) seal means extending between said shell members at the input and output ends thereof to isolate a space between the walls of the shell members from communication with both the interior of the inner shell member and the exterior of the outer shell member;
• and
• k) means for pressurizing said space between the shell members with oxygen at a level to maintain the seal means free of said pulp particles and gaseous bleaching agent and at a level which upon entering the reaction zone by way of the seal means, to--in which the flow of oxygen through any leak points in the seal means and in the inner shell is insignificant relative to the bleaching of the pulp particles with said ozone.