A method of producing chemical pulp including at least the following steps: a) wood chips or other comminuted ligno-cellulosic fibrous material is treated with a polysulfide-containing cooking liquor in an impregnation stage at a temperature of 90-145 C., and b) slurry of fibrous material from step a) is heated into cooking temperature and cooked for producing pulp having a desired kappa number. After step a) mercaptide ions are added into the slurry of fibrous material and the fibrous material is treated at cooking temperature in step b).

A method to treat fibrous materials for use in the formation of a biocomposite material that significantly reduces or eliminates the odors emitted from the fibrous materials is provided. In the method, the fibers or fibrous materials are initially treated to extract the raw fiber from the source plant material and the remove unwanted fractions of the fiber, such as the hemicellulose, lignin, and pectin, among others, leaving only the intact cellulose fibers. These cellulose fibers are then further processed in a second step to remove the odor from the cellulose fibers. The second step includes a combination of a second chemical treatment, dehumidification, and/or a cold plasma modification to render the cellulosic fibers odorless.

A method to treat fibrous materials for use in the formation of a biocomposite material that significantly reduces or eliminates the odors emitted from the fibrous materials is provided. In the method, the fibers or fibrous materials are initially treated to extract the raw fiber from the source plant material and the remove unwanted fractions of the fiber, such as the hemicellulose, lignin, and pectin, among others, leaving only the intact cellulose fibers. These cellulose fibers are then further processed in a second step to remove the odor from the cellulose fibers. The second step includes a combination of a second chemical treatment, dehumidification, and/or a cold plasma modification to render the cellulosic fibers odorless.

A cooking method and a digester system wherein partly digested cellulosic fiber source is compressed during cooking to provide high molecular weight lignin and pulp.

The present invention relates to a method of producing steam at a digester plant of a chemical pulp mill. Black liquor is discharged from the digester at a first temperature and pressure. The black liquor is treated in a flash tank for generating flashed black liquor and flash steam at a second temperature and a second pressure, which are lower than the first temperature and pressure. The flashed black liquor is taken for further treatment to the evaporation plant. The flash steam is led to an indirect heat exchange contact with clean liquid in the reboiler for boiling the liquid and for generating steam. The steam is led from the reboiler into a fan or compressor for increasing the steam pressure to a third pressure, which is higher than the second pressure and for adjusting the pressure of the steam in the flash tank. Steam at a third pressure is used for pretreating comminuted cellulosic fiber material, such as chips, prior to cooking.

The present invention relates to a method of producing steam at a digester plant of a chemical pulp mill. Black liquor is discharged from the digester at a first temperature and pressure. The black liquor is treated in a flash tank for generating flashed black liquor and flash steam at a second temperature and a second pressure, which are lower than the first temperature and pressure. The flashed black liquor is taken for further treatment to the evaporation plant. The flash steam is led to an indirect heat exchange contact with clean liquid in the reboiler for boiling the liquid and for generating steam. The steam is led from the reboiler into a fan or compressor for increasing the steam pressure to a third pressure, which is higher than the second pressure and for adjusting the pressure of the steam in the flash tank. Steam at a third pressure is used for pretreating comminuted cellulosic fiber material, such as chips, prior to cooking.

The invention relates to an improved profile bar screen for draining treatment liquor from a suspension of comminuted cellulose material and treatment liquor in an essentially cylindrical digester vessel. According to the invention is a profile bar screen designed with horizontal support arches 11 with integrated support shoulders 12 only at the outer ends of the support arch which support shoulders rest against the inside of the vessel wall 1. The invention combines the techniques from self-supporting screens with support members of weaker screen designs, avoiding need to make any additional welds in the classified pressure vessel wall of the digester. Installation of new screens in compartments previously equipped with blind plates in checkered screen rows may be done quickly and at less costs during shorter down time of digester.

The present invention relates to a delignification method which is applied for removing lignin from a biomaterial mixture in form of a pile, and essentially comprises the steps of piling of the biomaterials, treating the pile with an irrigation solution comprised of water or an aqueous solution comprising chemical materials, transferring the irrigation solution leached during reaching to the bottom of the pile to a pool or a storage unit with a drainage system, giving the irrigation solution which is transferred to the pool or the storage unit to irrigation again after controlling and optimizing, and leaching the pile by stopping the irrigation when the delignification process ends.

According to one aspect of the present disclosure, a mechanism and method is provided to clean and remove or separate cellulose fibers from the source fibrous material without stressing and/or damaging the cellulose fibers. The mechanism includes an agitator that directs the washing fluid in a vertical direction into engagement with the fibrous material to effect maximum cleaning of the cellulose from the remainder of the fibrous material without damaging or stressing the cellulose, thereby providing cellulose that can enhance the strength and other beneficial characteristics of a biocomposite material formed using the cellulose.

According to one aspect of the present disclosure, a mechanism and method is provided to clean and remove or separate cellulose fibers from the source fibrous material without stressing and/or damaging the cellulose fibers. The mechanism includes an agitator that directs the washing fluid in a vertical direction into engagement with the fibrous material to effect maximum cleaning of the cellulose from the remainder of the fibrous material without damaging or stressing the cellulose, thereby providing cellulose that can enhance the strength and other beneficial characteristics of a biocomposite material formed using the cellulose.