Valmet Ab

Metso Paper Sweden Ab

Valmet Aktiebolag

Kent-Olof Karlsson

Jonas Saetherasen

Daniel Trolin

Jonas Saetheråsen

The withdrawal screen section is for impregnation of chips during the manufacture of chemical pulp. Chips are steamed and impregnated in a low pressure impregnation vessel using pressurized hot spent cooking liquor BL. The spent cooking liquor produces most of the steam BLnecessary for steaming the chips. To reduce the need for adding fresh steam for chip steaming is a first withdrawal section in the impregnation vessel modified to be used both as a flash tank for warm pressurized wash filtrate and improved wash-out feature for the spent impregnation liquid behind the screen in the withdrawal section. The withdrawal volume is arranged with an upper part located above the liquid level LIQof the impregnation vessel. Additional pressurized warm wash liquor RECis added to the withdrawal volume and flashed off steam is led in a steam duct to the chip volume above the liquid level.

Method and system for impregnating chips

The arrangement and method are for the steam pre-treatment of chips during the production of cellulose pulp to avoid the blow-through of gases in the steam pre-treatment vessel. This prevents foul-smelling gases from being released into the atmosphere. Spreader nozzles for the injection of cooling fluid are arranged in the gas phase of the steam pre-treatment vessel. In the event of the risk for blow-through of steam, cooling that is proportional to the risk is activated. It is possible to avoid the emission of gases from the chip bin when interruptions in the process occur, whereby the release of odors into the surroundings can be minimized.

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Karlstad, Sweden

Kent-Olof Karlsson