Patent ID: 6808596
Filing Date: 2004-10-26
Classification: D21C

Abstract:
A system for the oxygen delignification of pulp having a lignocellulose-containing material having a mean concentration of 8%-18% pulp consistency, comprising:a pump for enabling movement of the pulp; a mixer in operative engagement with the pump for enabling mixing of the pulp and mixing of oxygen; a first and a second reaction stage for oxygen delignification of the pulp, the first reaction stage having a first reactor for permitting a first dwell time of 2-20 minutes, the second reactor stage having a second reactor for permitting a second dwell time of at least 20-200 minutes; first addition means in fluid communication with the first reaction stage for adding chemicals to the system at a first position prior to the first reaction stage; second addition means in fluid communication with the second reaction stage for adding chemicals at a second position after the first reaction stage and prior to the second reaction stage; third addition means for adding oxygen; the first reaction stage having a pipe loop disposed between the first and second addition means, the pipe loop having a length; and the first addition means being disposed at a distance from the second addition means that is shorter than the length of the pipe loop, the pipe loop being arranged to extend essentially in a horizontal plane.