According to an example aspect of the present invention, there is provided a process for the conversion of cellulosic waste material into a recycled cellulose product comprising the steps of cooking the waste material in a cooking liquor to remove lignin from the waste material and provide a delignified pulp, dissolving the delignified pulp in an ionic liquid to provide a spinning dope suitable for dry jet-wet spinning in an ionic liquid solution, and subjecting the spinning dope to a further processing step to provide a recycled cellulose product, said further step selected from the group of spinning cellulose fibers for use in textiles from the solution, extruding a film product for use in packaging, regenerating the dope as a hydrogel and regenerating the dope as an aerogel.

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, that adjust a high-pressure feeder of a feed system used in pulp production based on the fluid leakage through a low-pressure outlet of a high-pressure feeder. Methods can include obtaining multiple flow values, including (1) a make-up liquor flow value, (2) a black liquor flow value, (3) a white liquor flow value, (4) a chip chute circulation flow value, and (5) a high pressure feeder purge flow value. Methods can include determining a chip flow value specifying a flow of chips provided to the high-pressure feeder. Based on the flow values, methods can determine a fluid leakage value specifying an amount of fluid leakage through a gap between a pocket rotor and the housing of the high pressure feeder. Methods can adjust an annular gap based on the fluid leakage value satisfies a threshold leakage value.

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, that adjust a high-pressure feeder of a feed system used in pulp production based on the fluid leakage through a low-pressure outlet of a high-pressure feeder. Methods can include obtaining multiple flow values, including (1) a make-up liquor flow value, (2) a black liquor flow value, (3) a white liquor flow value, (4) a chip chute circulation flow value, and (5) a high pressure feeder purge flow value. Methods can include determining a chip flow value specifying a flow of chips provided to the high-pressure feeder. Based on the flow values, methods can determine a fluid leakage value specifying an amount of fluid leakage through a gap between a pocket rotor and the housing of the high pressure feeder. Methods can adjust an annular gap based on the fluid leakage value satisfies a threshold leakage value.

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 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 for producing a microbial cellulose pulp for the production of viscose dope, the method comprising the step of: exposing a microbial cellulose to a volume of water to form the microbial cellulose pulp for the production of viscose dope, wherein the cellulose concentration in the microbial cellulose pulp is less than 0.040 g of cellulose per mL of pulp.

Recycled fibers are produced from MDF or HDF containing material, for instance for use in MDF or HDF production by steaming (2) the MDF or HDF containing material for a predetermined time to obtain steamed material, subjecting the steamed material to a pulping process (3) to obtain a slurry, screening (4a, 4b) the slurry to remove oversize particles to obtain a screened slurry, dewatering (5) the screened slurry to obtain dewatered fibers and refining or fluffing (6) the dewatered fibers to obtain said recycled fibers. A method for producing MDF or HDF boards using such recycled fibers is also provided. Corresponding systems for producing recycled fibers and producing MDF or HDF boards are also provided.

A digestion accelerator which is safe and has a high digestion acceleration effect is provided. The digestion accelerator according to the present invention contains tannin or a polyphenol compound that is a hydrolysate of the tannin, a salt of the polyphenol compound, or ester of the polyphenol compound.

A digestion accelerator which is safe and has a high digestion acceleration effect is provided. The digestion accelerator according to the present invention contains tannin or a polyphenol compound that is a hydrolysate of the tannin, a salt of the polyphenol compound, or ester of the polyphenol compound.

Methods and systems of the present invention use mixed textile feedstock, which may include post-consumer waste garments, scrap fabric and/or other textile materials as a raw feed material to produce isolated cellulose and other isolated molecules having desirable properties that can be used and be used in the textile and apparel industries, and in other industries. A multi-stage process is provided, in which mixed textile feed material is subjected to one or more pretreatment stages, followed by at least two pulping treatments for isolating cellulose molecules and other molecular constituents, such as polyester. The isolated cellulose and polyester molecules may be used in a variety of downstream applications. In one application, isolated cellulose and polyester molecules are extruded to provide regenerated cellulose fibers and regenerated polyester fibers having desirable (and selectable) properties that are usable in various industrial applications, including textile production.