Method and arrangement for clarifying green liquor

A method for clarifying green liquor comprising:

• providing an arrangement for green liquor clarification comprising:
• a filter unit comprising a green liquor inlet, a slurry outlet and a filtrate outlet, and being constructed to filter green liquor;
• a source of flowing green liquor comprising a suspension of solids connected to the green liquor inlet of the filter unit;
• a pump constructed to force the flowing green liquor into the green liquor inlet to provide a Reynolds Number between 10,000-45,000 and cause a turbulent flow within the filter unit;
• a recirculation conduit connecting the slurry outlet to the source of flowing green liquor and being constructed for recirculating at least a portion of a slurry from the filter unit back to the source of flowing green liquor;
• a recirculation valve constructed to control an amount of slurry being recirculated from the slurry outlet to the source of flowing green liquor, wherein said filter unit comprising one or several filter elements, comprising one or several filter bodies having filter channels within the filter bodies with a filtering layer, during use a part of the green liquor is forced to pass through the filtering layer from a first inner surface to a second outer surface of the filtering layer forming a filtrate while the solids substantially remain in a residual part of the green liquor forming the slurry, wherein the filtering layer comprises a membrane material having pores, and said pores having a pore size of 0.1-10 micrometer, wherein the filter unit is constructed such that during use the filtrate flow from the filter unit is less than 50% of the green liquor flow into the filter unit, and the Renolds Number can be controlled by controlling the flow of the slurry out of the filer unit to provide the turbulent flow and prevent build-up of a filter cake in the filtering unit;
• a mud filter constructed for dewatering the slurry during use and form a dry solid suitable for landfill;
• and
• a slurry conduit connecting the slurry outlet to the mud filter;
• using the pump to flow the flowing green liquor from the source of green liquor into the inlet of the filter unit inlet;
• forming the slurry in the filter unit;
• flowing the at least a portion of the slurry through the recirculation valve, the recirculation conduit, and the slurry outlet to the source of flowing green liquor to recirculate the at least a portion of the slurry back to the source of flowing green liquor;
• flowing at least a portion of the slurry through the slurry valve and slurry conduit to the mud filter;
• operating and using the pump and/or the recirculation valve to control and provide a Renolds Number between 10,000-45,000 and provide a turbulent flow and prevent build-up of a filter cake in the filtering unit.