Apparatus for safely conducting pressurized peroxide bleaching

摘要

Apparatus for safely carrying out pressurized peroxide bleaching of pulp in a bleaching vessel at a consistency exceeding 8%, the bleaching vessel designed for at least 0.5 MPa overpressure, with the pulp being pumped to the bleaching vessel through a mixer at a temperature exceeding 90 DEG C., wherein a bypass conduit is provided to bypass the mixer and wherein a valve is provided in the bleaching vessel, the valve opening when the pressure in the bleaching vessel or an affiliated part thereof reaches a first set point.