Abstract: A process for the production of ethanol from biomass is disclosed. The process relates to the pretreatment of corncob biomass and includes the steps of exposing corncob to steam in a reaction vessel at an elevated temperature and reaction pressure for a preselected exposure time. Volatile compounds are continuously vented during pretreatment. The reaction pressure is released for explosive decomposition of the corncob biomass into fibrous solids and condensate. The exposure is preferably carried out at a temperature of 190-210° C. and a pressure of 190 psig to 275 psig and an exposure time of 3 to 10 minutes.

Abstract: A method to remove sulfides and other volatile contaminants from liquor vapor condensate in a pulp manufacturing process, where the mentioned liquor vapor condensate is fed into a stripper, which is part of a closed loop system including the stripper, a regenerative thermal oxidization process (RTO) and a SO2 scrubber, in which loop a gas is circulated, preferably air, and such components formed or stripped off, in this loop whereafter the circulating gas is stripped off sulfides and other volatile components from the liquor vapor condensate, whereafter the gas stream is fed into a RTO process, where the stripped off contaminants are combusted are under formation of SO2 and thereafter the SO2 enriched gas is led to a SO2 scrubber, where preferably alkali is used as absorption medium, and thereafter the circulating gas is returned back into the stripper.

Abstract: The invention relates to a method for avoiding and/or reducing the deposition of volatile and non-volatile wood components in gas-bearing systems, whereby at least one of the volatile wood components, at least partly, condenses in the gas-bearing system and the gas contains at least one compound with a similar condensation profile to the volatile wood component and which at least reduces the deposition of volatile wood components or the reaction products thereof. The invention further relates to a method for reducing and/or avoiding the deposition of wood components on machines and/or equipment components for the production of wood fiber materials from wood chippings, in which the shredding of the wood is achieved in the presence of a compound which forms a film on the surfaces of the above machines and/or equipment components and at least reduces the deposition of volatile wood components and/or the reaction products thereof.

Abstract: By the utilization of a jet ejector (such as a thermocompresser) in a cellulose chemical pulp mill, it is possible to effectively increase the utilization of steam. The volume of steam from a flash tank which flashes black liquor from a pulp digester may be increased (e.g. at least about 10%), while the volume and temperature of the liquor discharged from the flash tank are decreased and its concentration increased, by operatively connecting the jet ejector to the steam discharge from a flash tank. The jet ejector is supplied with higher pressure steam from another source which can result in a low pressure or partial vacuum condition in the flash tank. The flash tank may be a single flash tank or one of a series of flash tanks, and an ejector can be associated with at least another flash tank in the series.

Abstract: A method for conditioning an ozone gas recycle stream in an ozone pulp bleaching process. The method includes the steps of providing an oxygen containing feed gas to an ozone generator; generating ozone from said feed gas to produce an ozone rich oxygen gas; bleaching pulp with said ozone rich gas, thereby producing an exhaust gas containing contaminants including carbon dioxide and entrained pulp fibers; removing at least some of said contaminants by at least removing entrained pulp fibers from the exhaust gas to produce a recycle gas; directing said recycle gas into the ozone generator to provide at least a portion of said oxygen containing feed gas; and removing carbon dioxide during said contaminant removal step in an amount sufficient to a level of about 6 wt. wt. % to thus allow operation of the ozone generator at or approaching full capacity.

Abstract: The invention relates to a process system and a method for preliminary treatment of disintegrated cellulose-containing material, preferably wood chips, prior to pulp digestion. The process system and the method according to the invention make use of a process vessel intended to function both as a so-called chip bin and as a pre-impregnation vessel. The characteristics of the invention are that a sloping steaming vessel is arranged downstream of the process vessel for the purpose of separating an excess of pre-impregnation liquid from the pre-impregnated cellulose-containing material, that the sloping steaming vessel is arranged for supplying steaming vapor which preferably has been generated by flashing of extraction liquor from a pulp digester, and that the sloping steaming vessel is connected to a chip chute communicating with a condenser for connection to a system for managing foul-smelling process gases.

Abstract: A method for cooking chips, involving steaming the chips, impregnating the chips with impregnating liquid in an impregnation vessel, which impregnating liquid comprises fresh cooking liquid and spent liquor, extracting spent liquor from the impregnation vessel, cooking the impregnated chips in cooking zones including an introductory co-current cooking zone and a concluding counter-current cooking zone, extracting spent liquor from the digester at a position between the said co-current and counter-current cooking zones, transferring the said spent liquor from the digester to at least one position upstream of the digester, circulating the cooking liquid in a bottom circulation within the said counter-current cooking zone, heating the circulating cooking liquid by means of heat exchange, and supplying wash liquid to the bottom of the digester.

Abstract: A recycling process for garbage containing a high proportion of paper where printed paper is first separated from the garbage. The garbage is then into pieces and light and heavy components are separated out in a classification tank. The remaining organic mass suspended in water is hydrolyzed and subjected to anaerobic digestion followed by aerobic co-composting. The resulting solid is a high grade fertilizer while biogas produced by the process is converted to electrical energy in a combined cycle installation.

Abstract: A method for use in a batch digesting process is provided which includes the removal of a portion of the hot cooking liquor from the digester prior to the cook creating a liquid-vapor interface in the digester followed by the removal or purging of the vapors disposed above the liquid-vapor interface and the reduction of the pressure in the digester to about the saturation pressure of the hot cooking liquor. The inclusion of these steps in the process helps to eliminate a coating on the pulp fibers which has been found to inhibit the bleachability and runability of the fibers. Accordingly, an apparatus and method for the batch digesting of pulp fibers is provided which provides pulp fibers having improved bleachability and runability characteristics.

Abstract: A method of treating cellulose pulp which is subjected to an oxygen-delignification stage (3), a washing stage (4), an ozone-bleaching stage (1) and a further bleaching stage, for instance a peroxide-bleaching stage (7). A gas mixture of oxygen and ozone is delivered to the ozone-bleaching stage (1). The used gas mixture is regenerated, i.e. freed from carbon dioxide, and returned to the oxygen-delignification stage (3) and/or to a bleaching stage (7).

Abstract: A method for adjusting the chlorine equilibrium in a sulphate cellulose process, wherein part of the chlorine contained in the cycle is separated and removed. In the method, strong odour gases from the sulphate cellulose process are introduced into a soda recovery boiler for burning so that chlorine contained in the liquor is in the form of hydrogen chloride (HCl) in the upper part of the soda recovery boiler and can subsequently be separated from the flue gases in a flue gas scrubber. The chlorine equilibrium is adjusted by removing part of the chlorine-containing washing solution.

Abstract: The invention described in the specification is a method for removing hydrogen sulfide, volatile mercaptans and methyl sulfides from a paper mill condensate stream. In the method, carbon dioxide is injected into the condensate stream under pressure and the pressure of the resulting CO.sub.2 -enriched condensate is reduced rapidly to a pressure sufficient to cause hydrogen sulfide and volatile mercaptans to pass from the CO.sub.2 -enriched condensate to a gas phase. The gas phase containing hydrogen sulfide and mercaptans may then be recycled or burned and the treated condensate may be recycled for pulp washing. The method is very cost effective and can be easily retrofitted into existing paper mill systems without significant capital expenditures or production down time.

Abstract: A method for adjusting the sulphur/sodium ratio in a soda recovery boiler when strong sulphurous odour gases are burned therein. According to the method, sodium is introduced into the soda recovery boiler in an amount proportional to the amount of sulphur either as sodium hydroxide, sodium carbonate compounds or soap, whereby the sodium and sulphur react, forming sodium sulphate, which can be removed from the flue gases together with fly ash.

Abstract: To decrease the sulfur emissions of a sulfate cellulose mill, black liquor is heated before the last effect of the evaporation at a temperature higher than the cooking temperature of the sulfate cook and the sulfidity of white liquor is adjusted by adjusting the temperature and/or retention time of the heat treatment so that a predetermined amount of sulfur compounds are separated from the gaseous black liquor. Preferably, the sulfur containing gas is thereafter divided into different fractions and separately combusted.

Abstract: Off gases from black liquor heat treatment, evaporators, wood pulp digesters, etc. are treated to produce primarily hydrogen sulfide and sulfur free fuel gases such as methane, carbon monoxide, hydrogen, and ethylene. Then the hydrogen sulfide is used to produce sodium polysulfide in white liquor for cooking wood chips to produce pulp by the kraft process. Polysulfide may be formed in three different ways: by supplying air to a fuel cell into which white liquor and the hydrogen sulfide containing gas have been introduced; by bringing clarified white liquor and hydrogen sulfide containing gas into contact with a wet-proofed activated carbon catalyst and oxygen containing gas; or by bringing unclarified white liquor into contact with the gas and oxygen containing gas, with lime mud acting as a catalyst, and then clarifying the polysulfide-rich white liquor produced to remove the lime mud. The white liquor produced contains about 0.5-8% on wood sodium polysulfide.

Abstract: A method of producing high quantities of ethanol and a high quality pulp to produce a variety of papers. The method comprises preparing the bamboo by chipping, shredding and washing. This bamboo fiber is then processed in two stages of prehydrolysis to separate the ethanol producing portion from the pulp producing portion. The ethanol producing portion is condensed and subject to enzymatic hydrolysis and fermentation to produce an ethanol product. The pulp producing portion is processed in two stages of digestion to produce a pulp in high yield that is suitable to produce a variety of papers.

Abstract: A method for recovering turpentine and heat in a TMP process in which woodchips are heated in a preheater and the vent vapors from the preheater are passed to the condensing vapor zone of an evaporator condenser-reboiler having a condensing vapor zone and a boiling liquid zone. A major portion of the vent vapors are condensed so as to produce a turpentine-lean condensate and turpentine-rich vapor phase. The turpentine-rich vapor phase is withdrawn from the evaporator and passed to a turpentine condenser where it is cooled by indirect heat exchange contact with a cooling liquid to produce a condensate containing immiscible turpentine and aqueous phases. The turpentine and the aqueous phases are separated.

Abstract: In a combined process for the thermal and chemical treatment of lignocellulose-containing biomass and for the production of furfural, biomass is supplied to a cooker in batches, is heated in the cooker under the addition of cooking liquor, and cellulose or pre-treated biomass is withdrawn from the cooker in batches. In order to guarantee a high yield of furfural, cooking liquor is withdrawn from the cooker during the heating phase and is fed to a furfural production plant, and the cooking liquor at least largely freed from pentoses and furfural is returned to the cooker.

Abstract: There is provided a process and apparatus for improving the yield of turpentine collectable from the vent gases emanating from a pulp disgester in a kraft paper pulp Process. The apparatus is characterized by the insertion in a conventional turpentine recovery system of a gas/liquid contact vessel for intimately contacting the hot turpentine containing vent gas from a pulp digester with liquid foul condensate recycle from a turpentine decanter and a condenser for condensing the condensible components of the recycle treated vent gas, whereby the foul condensate is greatly improved as to contaminant content and rendered suitable for reuse in the plant.

Abstract: Eenrgy and process chemicals are recovered from spent liquor in pulp preparation by thermally decomposing the spent liquor to solid and gaseous products at an elevated pressure and with addition of oxygen. The supply of oxygen should be less than that stoichiometrically required for a complete combustion and the temperature at the decomposition should be below the temperature at which a melt is formed.After recovery of sulfur-containing compounds the gas formed can give off energy in a gas turbine, thereafter generate steam and finally be used for drying fuel which is subsequently gasified under pressure and provides a further contribution of energy in the form of a combustible gas.Process chemicals are recovered from the solid products in known manner.

Abstract: This invention comprises a method for increasing the accessibility of cellulose in lignocellulosic materials to chemical or biochemical reagents. The material is steam cooked for a predetermined time, then rapidly depressurized. A venting sequence is used to remove volatiles from the reactor. Optimal cooking times for normal and acid catalyzed cooking are disclosed, according to the discovery of a novel set of governing equations, wherein optimum cooking times can be determined as a time integration of reactor pressure.

Abstract: A method of cooking cellulose material and effectively preserving the heat and terpentine content of the cooking liquor is disclosed. The cooking liquor is allowed to expand and the expansion steam (blow steam) is conveyed into a bed of cellulose material in a storage container (3', 3) to heat and impregnate the cellulose material before cooking. A heated zone is maintained in the bed of material below the surface of the bed by regulating the flow of expansion steam into the container. Uncondensed, evil-smelling and poisonous gases are at the same time prevented from flowing out into the atmosphere. These gases are drawn off from the storage container for destruction.

Abstract: A versatile process and apparatus is presented for producing, in high yields, many different grades of pulp from a single wood specie or for pulping any specie or type of woody material, and for storage and recycling of the by-product liquid and gaseous materials. The process of this invention is virtually pollution free, and the reactant chemicals are recoverable from the by-products. In the alternative, the by-products themselves have a commercial value which may forestall recovery of the reactants. The lignin constituent extracted from the pulp is usable as a resin binder, a wood rehardening agent, or a glue.

Abstract: A continuous, low cost method of concentrating dilute streams containing fractions of adsorbable chemicals is disclosed which minimizes heat consumption and provides highly concentrated supplies of valuable chemicals which are suitable for reuse or sale without substantial further processing. The methods hereof are particularly adapted for concentrating waste condensates derived from pulp-making operations such as the Kraft or sulfite processes, but in general are also applicable for treating a wide variety of dilute organic or inorganic adsorbable chemicals.