The present invention relates to an improved method and device for treating biomass in which thermally treated biomass is discharged from a pressurized reactor and introduced into a blow tank, wherein the absolute pressure in the blow tank is maintained below atmospheric pressure. The slurry of biomass separated in the blow tank is then enzymatically treated.

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).

The production of steam-cracked biomass in the form of black pellets in the field of solid biofuels. More particularly, the present disclosure relates to the production of black pellets from a heterogeneous biomass. The aim of the present disclosure is to produce black pellets having good mechanical strength, good water resistance and an increased calorific value.

A method of digesting lignocellulosic material includes the steps of providing the lignocellulosic material and a caustic composition having a pH of at least about 10. The caustic composition includes water, an alkaline- or alkaline earth-metal hydroxide, and up to about 1 percent by weight based on a total weight of the composition of a branched digestion additive. The branched digestion additive has the structure: wherein A is at least one alkyleneoxy group and each alkyleneoxy group has from 2 to 4 carbon atoms, n is 0 or 1, B is a branched aliphatic hydrocarbon group having from 8 to 15 carbon atoms, X is H or B-0-(A).sub.m, and each m is independently an average value from 3 to 30, and wherein the caustic composition has a Draves Wetting Time of less than 100 seconds as determined using ASTM D2281. ##STR00001##

The present invention relates to an improved method and device for treating biomass in which thermally treated biomass is discharged from a pressurized reactor and introduced into a blow tank and then a flash tank, wherein the absolute pressure in the blow tank is maintained above atmospheric pressure and the absolute pressure in the flash tank is maintained below atmospheric pressure. The slurry of biomass separated in the flash tank is then enzymatically treated. The heat from the thermally treated biomass is recovered from the latent heat of a vaporous aqueous stream withdrawn from the blow tank.

The invention is related to a method for the preparation of kraft pulp with increased pulping yield from lignin-containing cellulosic material using polysulfide cooking liquor. In order to obtain a cost efficient system both in aspects of investment costs but also in aspects of heat economy of operating the process is most of the total charge of alkali charged as heated polysulfide liquor to an first atmospheric vessel, wherein the hot polysulfide liquor flashes off steam providing most if not all of the necessary steaming effect for the cellulose material. The polysulfide liquor is then allowed to impregnate the cellulose material at a temperature closer to cooking temperature but still so low that essentially no delignification occurs in impregnation vessel, as the H-factor in impregnation vessel is kept within 1-20.

The invention is related to a method for the preparation of kraft pulp with increased pulping yield from lignin-containing cellulosic material using polysulfide cooking liquor. In order to obtain a cost efficient system both in aspects of investment costs but also in aspects of heat economy of operating the process is most of the total charge of alkali charged as heated polysulfide liquor to an first atmospheric vessel, wherein the hot polysulfide liquor flashes off steam providing most if not all of the necessary steaming effect for the cellulose material. The polysulfide liquor is then allowed to impregnate the cellulose material at a temperature closer to cooking temperature but still so low that essentially no delignification occurs in impregnation vessel, as the H-factor in impregnation vessel is kept within 1-20.

A method for continuously cooking grass raw materials, includes: (1) preparing grass raw materials by conventional dry or wet method to obtain a chopped grass; (2a) conveying the chopped grass into a T-shaped tube, adding a cooking liquor from a top of the tube and mixing with the chopped grass tube to obtain a forage; (2b) adding steam to the forage being in the horizontal tube, the forage being heated and going into a spherical mixer; (2c) adding a cooking liquor extruded by a dehydration spiral into the spherical mixer, mixing uniformly with the forage in the spherical mixer; (3) conveying the forage after the pre-cooking process to a digester, heating the cooking liquor by a heater arranged outside the digester, and sending the cooking liquor back to the digester for cooking the forage to obtain a pulp of the grass raw materials.

A method for continuously cooking grass raw materials, includes: (1) preparing grass raw materials by conventional dry or wet method to obtain a chopped grass; (2a) conveying the chopped grass into a T-shaped tube, adding a cooking liquor from a top of the tube and mixing with the chopped grass tube to obtain a forage; (2b) adding steam to the forage being in the horizontal tube, the forage being heated and going into a spherical mixer; (2c) adding a cooking liquor extruded by a dehydration spiral into the spherical mixer, mixing uniformly with the forage in the spherical mixer; (3) conveying the forage after the pre-cooking process to a digester, heating the cooking liquor by a heater arranged outside the digester, and sending the cooking liquor back to the digester for cooking the forage to obtain a pulp of the grass raw materials.