31results about "Regeneration of sulfite lye" patented technology

The invention relates to a red liquor using method, namely a sulfite pulping papermaking waste liquid method, in particular to a papermaking red liquor sugar component using method. The papermaking red liquor sugar component using method is characterized in that the red liquor is neutralized, a bag type filter is used for removing macromolecule solid contents and colloid in the red liquor, lignosulfonate in the papermaking red liquor is removed by adopting an ultrafiltration system and a nanofiltration membrane system, and the liquid obtains sugar liquor with the transmittance of 90%, the sugar content in solute of 90% and the conductivity of 200muS/m finally after decoloration and desalination. The sugar liquor can be used for preparing acetone butanol, ethanol, methane and biopesticide in a fermentation mode, or preparing ethylene glycol, propylene glycol and other polyatomic alcohol through hydrogenation and hydrogenolysis, or preparing sweet dew sugar and wood sugar in a grading concentration and purification mode by using a simulation moving bed chromatograph. The papermaking red liquor sugar component using method solves the pollution problem of the papermaking red liquor existing for a long period, and achieves high-efficient and high-value use of the red liquor resources, especially the sugar resources.

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.

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 present invention relates to a combined production process capable of utilizing filter membrane technique to implement zero discharge of pulp production and comprehensive utilization. It is characterized by that said production process can utilize filter membrane technique to make waste liquor produced in every independent water-using work section in the course of pulp production undergo the process of purification treatment, and make the purified water obtain circular utilization so as to implement zero discharge of waste liquor.

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.

The invention relates to a method for reducing phosphorus in effluent or filtrate from a process which comprises a stage in which green liquor dregs are filtered using a green liquor dregs filter and at least one stage in which conditions are acidic, wherein the method comprises the steps of: a) obtaining an effluent or filtrate from a stage in which conditions are acidic; b) adjusting pH of at least a portion of the effluent or filtrate to alkaline with an alkaline agent; c) allowing phosphorus to be precipitated in form of a phosphate salt; d) separating the precipitate to produce purified effluent or filtrate and a sludge comprising the precipitate; and e) filtering the sludge comprising the precipitate obtainable from step d) using the green liquor dregs filter.

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 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.

Method for recovering chemicals and energy from sulphite thick liquor containing organic and inorganic compounds obtained when producing pulp by chemical delignification of fibrous raw material using a sulphite pulping process, the method including processing of the organic and inorganic compounds at a global temperature above 800° C. whereby producing partly at least one phase of a liquid material and partly at least one phase of a gaseous material. The processing is carried out by gasification of the sulphite thick liquor in a gasification reactor at sub-stoichiometric conditions and in the presence of an oxidizing medium. The reactor has an opening in its bottom in the form of a chute which opens directly into a quench compartment.