Abstract: A method for controlling discharges of nitrogen compounds in the production of cellulose carbamate (CCA). Microcrystalline cellulose is produced from chemical pulp produced at a pulp mill, such that the chemical pulp is subjected to acid hydrolysis at an elevated temperature to form microcrystalline cellulose (MCC) and hydrolysate, and the MCC is reacted with urea to produce cellulose carbamate whereby ammonia is released. The microcrystalline cellulose production and the cellulose carbamate production are integrated into the pulp mill having a flue gas system such that carbon dioxide from the flue gases is reacted with released ammonia to produce urea, which is used in the carbamate production.

Abstract: A method for controlling discharges of nitrogen compounds in the production of cellulose carbamate (CCA). Dissolving pulp (DP) or kraft pulp is produced at a pulp mill, and the DP or kraft pulp is activated. The activated pulp is reacted with urea to produce cellulose carbamate whereby ammonia is released. The cellulose carbamate production is integrated into the pulp mill having a flue gas system such that carbon dioxide from the flue gases is reacted with released ammonia to produce urea, which is used in the carbamate production.

Abstract: A method for controlling discharges of nitrogen compounds in the production of cellulose carbamate (CCA). Microcrystalline cellulose is produced from chemical pulp produced at a pulp mill, such that the chemical pulp is subjected to acid hydrolysis at an elevated temperature to form microcrystalline cellulose (MCC) and hydrolysate, and the MCC is reacted with urea to produce cellulose carbamate whereby ammonia is released. The microcrystalline cellulose production and the cellulose carbamate production are integrated into the pulp mill having a flue gas system such that carbon dioxide from the flue gases is reacted with released ammonia to produce urea, which is used in the carbamate production.

Abstract: A process for producing microcrystalline cellulose from fibrous cellulosic material by acid hydrolysis at an MCC plant. In this process a suspension of cellulosic pulp is thickened, so that filtrate is formed. A consistency of the thickened suspension is adjusted to 5-40% by adding dilution liquid, and the pH of the suspension is adjusted to a value of 4 or less with acid. The pulp suspension is subjected to acid hydrolysis of at least 120° C. in a reactor to produce a mixture of microcrystalline cellulose and hydrolysate. The mixture is discharged from the reactor to a lower pressure and lower temperature to flash the mixture and generate flash steam. Microcrystalline cellulose is separated from hydrolysate. The separated cellulose is washed in one or several washing apparatuses. The consistency of the microcrystalline cellulose is increased by thickening and/or drying for further processing.

Abstract: 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.

Abstract: 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.