Valmet Ab

Kvaerner Pulping Ab

Kvaerner Pulping Technologies Ab

Metso Fiber Karlstad Ab

Metso Paper Sweden Ab

Magnus Ingelman

Anita Markusson

Jan Tjernberg

John Johnson

Martin Wimby

Eva Hogebrandt

Patrik Lownertz

Roger Jansson

Zicheng Zhang

Per Larsson

Hans-ANGke Karlsson

Sanchuan Guo

The invention relates to a method for clarification of raw green liquor in a sedimentation tank. According to the invention is a part of dregs separated in the sedimentation tank recirculated back into the inflow of raw green liquor, and preferably after passing the dregs through at least one turbulence generator () that could break up larger dregs particles into smaller dregs particles, and thus create larger total surface on the dregs particles, improving sedimentation rate in the sedimentation tank. In a preferred embodiment is the recirculated dregs added into the flow of raw green liquor before a flocculant is added into the flow of raw green liquor and mixed recirculated dregs.

Green liquor clarification using sedimentation tank during white liquor preparation

The method and apparatus are for obtaining strong white liquor and lime mud with low residual alkali content from causticized liquor. The first filter (F) receives causticized liquor from causticizing vessels (CT-CT-CT) and is designed as pressurized two stage disc filter with 2 separate vat parts. In the first vat part non-diluted white liquor is obtained as a filtrate from the causticized liquor. The first lime mud cake accumulated on the filter discs in the first vat part is scraped off and diluted before being fed to the second vat part. In the second vat part weak liquor is obtained as a filtrate from the re-slurried first lime mud cake. The second lime mud cake accumulated on the filter discs in the second vat part is washed before being scraped off and diluted before being fed to subsequent lime mud handling.

Method and apparatus for obtaining strong white liquor and lime mud with low residual alkali level

The method and arrangement is for cleaning at least one of filter sheets and filter cakes in a pressurized white liquor filter with spray nozzles and driving fluid. The white liquor filter is used in a causticizing process in which green liquor is causticized before the white liquor filter by the addition of lime and in which it forms during the process a lime mud slurry. The white liquor filteris used to separate white liquor from the lime mud. The driving fluid for the spray nozzle is constituted principally by the filtrate that is obtained from the filter.

Method and device for cleaning of filter

The method is for production of green liquor in association with a causticizing process during recovery of chemicals in manufacture of sulphate pulp. A smelt () of chemicals principally consisting of Na2S and NaCOfrom a soda boiler () is provided. Weak liquor () that contains dissolved NaOH and CaO is provided. A dissolving tank () is provided in which the smelt () from the soda boiler () is dissolved in the weak liquor () it order to form green liquor (). A solution of NaOH is added to the weak liquor (), at a position before the weak liquor () is added to the dissolving tank, in order to increase the concentration of NaOH in the weak liquor () such that a fraction of CaO that is presently dissolved in the weak liquor () precipitates.

Method for the production of green liquor

The pipe system is for receiving and transporting lime sludge from a filter medium in a continuously operating pressurized filter in a causticizing process, where lime sludge is scraped off from the filter medium and falls down into receiving chutes for the lime sludge. Conventional storage tanks for scraped-off lime sludge and their mechanical agitators are thus replaced by a pipe system where the pipe system does not have a mechanical agitator at all but has a flow cross section which maintains a flow rate in the lime sludge so that sedimentation of the lime sludge does not take place from the receiving chute to the feed-out opening of the pipe system.

Pipe system for receiving and transporting lime sludge from a white liquor filter

Filters employing 'filling bodies' to reduce the amount of backwashing

Growing community of inventors

Karlstad, Sweden

Magnus Ingelman