Abstract: The feed system is for a continuous digester where at least two pumps are arranged in parallel in the bottom of a pre-treatment vessel and a liquid level of at least 10 meters is established. The system makes it possible to provide a feed system with an improved accessibility and more reliable operation, and to operate the main part of the pumps at optimal efficiency even if the production capacity is reduced.

Abstract: The feed system is for a continuous digester where at least two pumps are arranged in parallel at the bottom of a pre-treatment vessel. Each pump has its own independent transfer line extending to the top of the digester. The system makes it possible to provide a feed system with an improved accessibility and operational reliability, and to operate the main part of the pumps at optimal efficiency even if the production capacity is reduced.

Abstract: The feed system is for a continuous digester where at least two pumps are arranged in parallel at the bottom of a pre-treatment vessel and a stirrer is provided in direct connection to inlets to pumps. The system makes it possible to provide a feed system with an improved accessibility and operational reliability, and to operate the main part of the pumps at optimal efficiency even if the production capacity is reduced.

Abstract: The method is for the impregnation of chips during the manufacture of chemical pulp. The chips are continuously fed without preceding steam treatment to the top of an impregnation vessel that maintains atmospheric pressure. Impregnation fluid (BL) is added to the impregnation vessel and establishes a fluid level (LIQ_LEV). The chips that have been added establish a chips level (CH_LEV) that lies at least 3-5 meters over the fluid level. The temperature at the top of the vessel essentially corresponds to ambient temperature. Impregnation fluid BL is fed in to the impregnation vessel in such an amount and at such a temperature that the temperature that is established at the fluid level (LIQ_LEV) is established within the interval 90-115° C., preferably within the interval 95-105° C.

Abstract: The vessel in which the chips are pre-treated with steam (ST) is provided with a ventilation channel at the top of the vessel for the leading away of weak gases to a weak gas system (NCG). A simple safety system has been installed with the aim of guaranteeing that these weak gases do not reach a level of concentration at which these weak gases become explosive. The safety system has a control unit (CPU) that detects a process parameter that is indicative of the fraction of moisture in the weak gases and opens dilution lines that supply air for the dilution of the weak gases in the ventilation channel. It is appropriate that the dilution take place in stages, where the dilution lines are opened in stages with successively increasing temperature of the weak gases.

Abstract: 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 odours into the surroundings can be minimised.

Abstract: The method is for the impregnation of chips during the manufacture of chemical pulp. The chips are continuously fed without preceding steam treatment to the top of an impregnation vessel that maintains atmospheric pressure. Impregnation fluid (BL) is added to the impregnation vessel and establishes a fluid level (LIQ_LEV). The chips that have been added establish a chips level (CH_LEV) that lies at least 3-5 meters over the fluid level. The temperature at the top of the vessel essentially corresponds to ambient temperature. Impregnation fluid BL is fed in to the impregnation vessel in such an amount and at such a temperature that the temperature that is established at the fluid level (LIQ_LEV) is established within the interval 90-115° C., preferably within the interval 95-105° C.