A method and system for heating a hydraulic digester, such as a single-vessel hydraulic digester, which has a top separator, a level of chips and a liquid phase above the level of chips. The method includes: a. entraining chips in liquor to produce a slurry having a first temperature, b. feeding the slurry of chips to the digester through the top separator, c. supplying direct steam to the liquid phase between the level of chips and the top separator to heat the slurry to a second temperature for the impregnation stage, wherein the steam is fed by using at least one steam injector having a plurality of steam discharge openings; and d. heating the slurry to a third temperature and cooking the chips in a cooking zone, and withdrawing the cooked pulp from the bottom of the digester.

In general, the present invention is directed to a method of cooking wood in a cooking liquor medium. The method comprises a step of providing wood to a treatment vessel and contacting the wood with a digester additive composition. The composition comprises a first surfactant comprising an anionic surfactant, a derivative thereof, a salt thereof, or any combination thereof and a second surfactant comprising a polyoxyalkylene glycol or a derivative thereof. Additionally, according to another embodiment, the present invention is directed to a digester additive composition comprising a first surfactant comprising an anionic surfactant, a derivative thereof, a salt thereof, or any combination thereof and a second surfactant comprising a polyoxyalkylene glycol or a derivative thereof.

In general, the present invention is directed to a method of cooking wood in a cooking liquor medium. The method comprises a step of providing wood to a treatment vessel and contacting the wood with a digester additive composition. The composition comprises a first surfactant comprising an anionic surfactant, a derivative thereof, a salt thereof, or any combination thereof and a second surfactant comprising a polyoxyalkylene glycol or a derivative thereof. Additionally, according to another embodiment, the present invention is directed to a digester additive composition comprising a first surfactant comprising an anionic surfactant, a derivative thereof, a salt thereof, or any combination thereof and a second surfactant comprising a polyoxyalkylene glycol or a derivative thereof.

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 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.

In general, the present invention is directed to a method of cooking wood in a cooking liquor medium. The method comprises a step of providing wood to a treatment vessel and contacting the wood with a digester additive composition. The composition comprises a first surfactant comprising an anionic surfactant, a derivative thereof, a salt thereof, or any combination thereof and a second surfactant comprising a polyoxyalkylene glycol or a derivative thereof. Additionally, according to another embodiment, the present invention is directed to a digester additive composition comprising a first surfactant comprising an anionic surfactant, a derivative thereof, a salt thereof, or any combination thereof and a second surfactant comprising a polyoxyalkylene glycol or a derivative thereof.

In general, the present invention is directed to a method of cooking wood in a cooking liquor medium. The method comprises a step of providing wood to a treatment vessel and contacting the wood with a digester additive composition. The composition comprises a first surfactant comprising an anionic surfactant, a derivative thereof, a salt thereof, or any combination thereof and a second surfactant comprising a polyoxyalkylene glycol or a derivative thereof. Additionally, according to another embodiment, the present invention is directed to a digester additive composition comprising a first surfactant comprising an anionic surfactant, a derivative thereof, a salt thereof, or any combination thereof and a second surfactant comprising a polyoxyalkylene glycol or a derivative thereof.

A method and an arrangement for generating process steam at a chemical pulp mill. Water is heated by subjecting it to an indirect heat exchange contact with steam in a heat exchanger. The water is heated with live steam produced in a steam boiler for generating process steam, whereby the live steam is condensed and the generated condensate is recovered. The process steam is subjected to a direct heat exchange contact with a material for heating the material. The water used for process steam production is obtained from secondary condensates, purified waste water and/or raw water. Process steam can be used in the treatment of cellulosic fibrous material, such as chips.

A method and an arrangement for generating process steam at a chemical pulp mill. Water is heated by subjecting it to an indirect heat exchange contact with steam in a heat exchanger. The water is heated with live steam produced in a steam boiler for generating process steam, whereby the live steam is condensed and the generated condensate is recovered. The process steam is subjected to a direct heat exchange contact with a material for heating the material. The water used for process steam production is obtained from secondary condensates, purified waste water and/or raw water. Process steam can be used in the treatment of cellulosic fibrous material, such as chips.

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.