Green liquor clarification method for cellulose pulp production, involves using filtering layer which is made of membrane material with pores having predetermined pore size.

• NOVELTY - The green liquor clarification method involves filtering of flowing suspension containing solids and bringing in contact with a first filter unit (4). The filter unit consists of filter elements (12) with filter bodies having filter channels. A part of the suspension is forced to pass through the filtering layer to forming a filtrate while the solids substantially remain in a residual part of the suspension forming a slurry. The filtering layer is made of a membrane material with pores having a pore size of 0.1-10 micrometer (um), more preferred 0.1-5 um and most preferred 0.2-1.0 um. USE - Green liquor clarification method for cellulose pulp production. ADVANTAGE - Provides a filtering process which is a continuous process with no build up of a filter cake and is very effective in leading to a very high separation degree of dregs which is up to almost 100 percent and the filtrated green liquor is almost free from slurry. Characteristic green color of the green liquor is removed with the dregs which simplifies the identification both of disturbances in the filtration process and in the recovery flimace under normal operating conditions. Investment costs for the cross-flow filtration equipment is very minimal. The space required is much smaller than the space required for the sedimentation tanks. Minimizes oxidation of the valuable sulfide content of the green liquor since there is no contact with the surrounding air, nor is pressurized air used in the equipment. The closed system with no contact with surrounding air or use of vacuum shows that the temperature of the green liquor is maintained at a high level. The modular design of the filters facilitates an incremental capacity increase with minimal investment cost. Provides a simple system with minimal moving parts so less labor is needed for oversight and maintenance. Provides less lime make-up or decreased content of inerts in the lime at the same make-up rate due to less particles in the green liquor Less dregs carryover improves clarification of white liquor and improves mud dewatering and lower energy consumption. Enables efficient removal of non-process elements for minimum operation cost and low landfill volumes. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for an arrangement for green liquor clarification. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic of an arrangement for cleaning green liquor using cross-flow filtration. First filter unit (4) Filter elements (12) Conduit (21) Tank (40) Collecting tank (42)

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NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

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