31results about "Regeneration of sulfite lye" patented technology

A method for the production water insoluble reactive lignin having low sulfur content and lignosulfonates from lignocellulosic material in a batch or continuous process. Lignocellulosic material is fractionated to produce water insoluble native lignin and lignosulfonates in various ratios, while preserving the cellulose and hydrolyzed hemicelluloses using water, ethanol and sulfur dioxide.

The arrangement is for positioning equipment in association with an opening in a boiler wall and has a rotation mechanism that rotates the equipment around a virtual rotation axis that lies within the outer wall of the boiler. During the use of a liquor spreader for the introduction of combustible material, the opening of the liquor spreader is arranged in the virtual center of rotation so that the point at which the combustible material is introduced is retained independently of the angle of rotation. The liquor spreader is united either with a glide device or the guide in the rotation mechanism.

Methods of converting a sulfide in a composition to polysulfide are described, one method comprising the steps of exposing the composition to conditions and for a time sufficient to cause conversion of at least a portion of the sulfide, to polysulfide to form a modified composition; and controlling the conversion to polysulfide by measuring a color parameter of the modified composition.

The invention relates to paper making industry clean production, in particular to an alkali recovery method based on paper making black liquid. The method comprises the following steps of: 1) adding carbon powder in paper making black liquid, introducing CO2 gas for carrying out primary hydrothermal carbonization, and carrying out filtering to obtain primary hydrothermal carbonization liquid and primary hydrothermal carbonization materials; 2) adding crude activated carbon into the primary hydrothermal carbonization liquid obtained in the first step, carrying out secondary hydrothermal carbonization under the CO2 gas introduction condition, carrying out filtering to obtain secondary hydrothermal carbonization liquid and secondary hydrothermal carbonization materials, evaporating the secondary hydrothermal carbonization liquid, regulating the pH (Potential Of Hydrogen), and carrying out causticization treatment to obtain alkali liquid. The method provided by the invention has the advantages that because the alkali recovery work procedure is a bottle neck of most alkali process pulp making paper making plants in prior art, after the efficiency of the process is improved, the pulp making capability of the paper making plants can be greatly improved, meanwhile, the by-production of high-added-value activated carbon and white carbon black can be realized, and further, the scale benefits of the paper making enterprises can be integrally improved.

The invention relates to a process for performing ammonium sulfite pulping by using a sulfur-containing flue gas absorber, which comprises the following steps: (1) performing desulphurization on flue gas by using ammonia water, wherein the flue gas is sulfur-containing flue gas; and (2) performing ammonium sulfite pulping during papermaking by using sulfurous acid mixed solution obtained after the desulphurization. In the process, a high-efficiency flue gas absorption system is adopted; the obtained ammonium sulfite is used for ammonium sulfite pulping in papermaking industry; and heavy contaminated condensate produced by pulping can also be used for absorbing sulfur dioxide in the flue gas. The scheme of the invention not only minimally reduces the environmental pollution, but also recycles the resources. The process is particularly suitable to be used in a paper mill with a self-owned power plant.

The present invention describes a process and system of producing methanol from methanol condensates. In a preferred embodiment the condensates are biomethanol condensates from chemical pulp mills and various waste sources used to produce a purified biomethanol. Pulp condensates are rich in methanol and contain many other contaminants. Presently, most chemical pulp mills, such as Kraft pulp mills use steam stripping to remove and concentrate the methanol and burn the methanol onsite along with the contaminants. A combination of treatments that include air stripping, steam stripping, distillation and reverse osmosis is described to obtain purified biomethanol suitable for sale or use on site.

The present invention relates to a process for the controlling the sodium and sulfur levels in a pulp mill, comprising the steps of: a) providing a pulp mill stream comprising sulfide and having a total alkali concentration of at least 2 Molar; b) supplying a portion of the pulp mill stream to a reactor comprising sulfide oxidizing bacteria and removing sulfide from the pulp mill stream by subjecting said stream to sulfide oxidizing bacteria in the presence of oxygen, and at a pH in the range 8 to 11, to oxidize the sulfide to elemental sulfur, c) withdrawing from the reactor a treated pulp mill stream comprising sulfur, wherein the portion of the pulp mill stream is mixed with a portion of the sulfide oxidizing bacteria present in the reactor prior to supplying the pulp mill stream to thereactor in step b).

The invention relates to a method for reducing phosphorus in effluent or filtrate from a process which comprises at least one stage in which conditions are acidic, wherein the method comprises the steps of: a) obtaining a first portion of an effluent or filtrate from a stage in which conditions are acidic; b) obtaining a second portion of an effluent or filtrate from the same or different stage in which conditions are acidic; c) adjusting pH of the first portion of the effluent or filtrate to alkaline with an alkaline agent; d) allowing phosphorus to be precipitated in form of a phosphate salt; e) separating the precipitate by filtration to produce purified effluent or filtrate; and f) combining the purified effluent or filtrate with the second portion of the effluent or filtrate. The process may be a chemical pulping process in which pulp is cooked in a digestion apparatus (1), washed in a washing apparatus (2), bleached in a bleaching apparatus (3) in which an acidic bleaching stage (3') takes place, after which the pulp is separated in a separation apparatus (4) from an acidic effluent or filtrate which is divided into the first and second portions of effluent or filtrate. The invention also relates to the corresponding chemical pulping and purification apparatus.

There is provided a process for improving the quality of lignosulfonate at least partly derived form a spent sulfite cooking liquor in at least two steps, comprising: one step in which a lignosulfonate-containing fraction at least partly derived from the spent sulfite cooking liquor is subjected to filtration using a membrane having a cut-off of 40-150 kD (high cut-off) at the pressure, flow rate and temperature of the step and the permeate is recovered; and another step in which a lignosulfonate-containing fraction at least partly derived from the spent sulfite cooking liquor is subjected to filtration using a membrane having a cut-off of 1-20 kD (low cut-off) at the pressure, flow rate and temperature of the step and the retentate is recovered. Products, uses thereof as well as a system are also provided.

The present invention relates to a method for reducing phosphorus in effluent or filtrate from a process comprising a stage of filtering green liquor sludge with a green liquor sediment filter and at least one stage in which conditions are acidic, wherein the method comprises the steps of: a ) taking effluent or filtrate from a stage where conditions are acidic; b) adjusting the pH of at least a portion of said effluent or filtrate to alkaline with an alkaline agent; c) allowing phosphorus to precipitate as phosphate; d) separating said precipitate to produce a purified effluent or filtrate and a sludge containing said precipitate; and e) filtering the sludge containing said precipitate obtained from step d) with a green liquor sediment filter.

The invention discloses a treatment and recycle process for sulfite pulping waste liquid. The treatment and recycle process mainly comprises pretreatment, lignin purification, replacement and modification, nanofiltration and concentration. According to the process, purified lignin sulfonate is obtained by adopting a membrane separation technology; through modification, the sulfonate can be used as a dye dispersant, can be used for preparing a high-efficiency cement dispersant, can also be used for preparing drilling mud diluent and the like, can serve as a raw material of vanillin, and can be used for preparing high-quality food spices and the like; high-value utilization of waste is realized. After the sulfite is treated by the process, over 80 percent of lignin sulfonate, 70 to 90 percent of reducing sugar and 60 to 80 percent of water can be recycled; the production cost can be reduced for production enterprises; waste water emission amount can be greatly reduced; waste solid emission amount can be greatly reduced; the requirement on environment friendliness of the enterprises can be met more easily; the aims of saving energy and reducing emission can be fulfilled for the enterprises.

The closed treatment of papermaking waste water with sulfites, including ammonium sulfite and sodium sulfite, consists of bacteria strain culture, biochemical treatment, separation of lignin and other matters in alkali or neutral condition, gas floating, filtering, and returning filtrate for reuse in digestion and pulp making. The present invention has the advantages of complete treatment, recovery of all water and reduced investment and running cost.