mechanical pulp delignification process

    Fungal delignification and biomechanical pulping of wood

    Dec 23, 2006· Biopulping, defined as the treatment of wood chips with lignin-degrading fungi prior to pulping, saves substantial amount of electrical energy during mechanical pulping, results in stronger paper, and lowers the environmental impact of pulping Optical properties are diminished; however, brightness can be restored readily with peroxide bleaching.

    Pulping and Papermaking of Non-Wood Fibers

    The delignification process of gramineous fiber materials can also be divided into three stages: the main stage of lignin removal, the supplementary stage of lignin removal, and the stage of residual lignin removal , Chemi-mechanical pulping has the advantages of high pulp yield and no need for chemical recovery systems.


    Purpose of pulping Purpose of cooking in chemical pulp production is to use chemicals and heat to remove fiber binding lignin so chips defibrate easily Fibers containing cellulose are tried to keep as long, unbroken and strong as possible Also wood extractives which can later cause foaming and precipitants in the process are tried to remove.


    May 30, 2014· KTH Royal Institute of Technology, School of Chemical Science and Engineering, Stockholm, Sweden Search for more papers by this author.

    Mechanical pulping

    The invention relates to a method for making Mechanical pulp comprising digesting wood chips in the digester to create unbleached pulp and then bleaching the pulp, wherein the pulp is treated with from 0002 weight% to 002 weight% of an organic sulfide chelating agent before or during bleaching Optionally, the process further comprises adding an additional chelant, adding a surfactant and.


    submitting to you the report on Pulp and Paper: Bleaching and the Environment , effluents include extended delignification, more efficient washing of pulp before bleaching, and the substitution of chlorine compounds for elemental chlorine , The chemi-thermo-mechanical pulping process -- a relatively new process which is.

    Bleaching and productivity

    A clean and pure pulp is essential for mechanical pulp producers to meet customer demands BIM’s BIMPRO concept, combining expertise and chemistry, will help you to increase the pulp performance and save costs The main benefits using BIMPRO are: - Increased brightness level - Increased levels of residual peroxide - Drainage improvement.

    Sulfate Pulp

    Pulp for the paper industry can be made by chemical or mechanical process Chemical pulp can be made by two different methods: sulphate or sulphite methods The process is based on chemical fibrillation, and the lignin that bonds the fibres together is dissolved The strength of the sulphite pulp is much less than the strength of the sulphate.

    Peroxide Bleaching

    Jul 17, 2015· This course focuses on peroxide bleaching of chemical pulp, but peroxide is also used extensively for mechanical pulp bleaching Category , 71 videos Play all Kraft Pulp Process.


    PULP BLEACHING CONTROL AND OPTIMIZATION , Pulp used in the paper making process can be made whiter by several methods These meth-ods can be grouped in two categories: bleaching , Many mechanical pulp mills inject hydrosulflte at two locations in the process in order to control the.


    manufacture chemi-mechanical pulp from rapeseed straw by the cold pulping process Three cold pulping processes, namely neutral sulphite, alkaline sulphite, and caustic soda ones, were conducted at a room temperature under laboratory conditions Besides total pulp yield, the influence of chemical.


    OXYGEN DELIGNIFICATION Introduction Oxygen delignification is a process between cooking and bleaching sequences, where part of the residual lignin left in pulp after cooking is removed using oxygen and alkali Oxygen delignification is a direct extension to delignification in cooking The targeted reactions are the oxidation of lignin and.


    32321 - Mechanical pulping Various mechanical pulping processes are in use and they generally present comparable results Stone Groundwood Pulping (SGW) This is the oldest mechanical process where logs are forced into contact with a rotating grindstone in the presence of water.


    tation from black liquor [8] Mechanical pulping is by definition pulping with mini-mal delignification According to Bier-mann [5], mechanical pulping has yields between 85% and 97% Many mechani-cal pulp mills achieve pulp yields greater than 95% using state-of-the-art thermo-mechanical pulping (TMP) Biorefinery.

    A method for integrated optimization of chlorine dioxide

    A Method for Integrated Optimization of Chlorine Dioxide Delignification of Bagasse Pulp Yongjun Yin, Xueping Song, Chongxin Li, and Shuangxi Nie * Chlorine dioxide bleaching is an important component of elemental chlorine-free bleaching.

    Pulp and Paper Industry

    Kraft pulp: Chemical pulp that has been manufactured using sodium sulfate as the main cooking chemical Lignin: This is the binding substance in natural fibers and is a complex organic polymer with an irregular structure Mechanical pulp: Papermaking pulp made entirely by mechanical means from various raw materials ie by grinding wood against an abrasive or by processing wood.

    The chemical reactions in Kraft pulping process

    Jun 30, 2015· Kraft pulping process is the most used pulping process in the world In this process lignin goes into the reactions with the cooking liquor chemicals and split into fragment These fragments dissolved with the solution and wood disintegrates into fiber.

    ANDRITZ acquires KEMPULP

    International technology Group ANDRITZ has acquired the Swedish company KEMPULP, a specialist provider of process technologies for the chemical pulping industry The company designs and markets technologies used in chemical pulping, including pulp washing, oxygen delignification.

    On the delignification mechanism in kraft pulping

    The successive retardation of lignin dissolution towards the end of a kraft pulping process can be explained by the predominance of biphenyl and biphenyl ether structures being present in the lignin.

    Bleaching of wood pulp

    Mechanical pulp retains most of the lignin present in the wood used to make the pulp and thus contain almost as much lignin as they do cellulose and hemicellulose It would be impractical to remove this much lignin by bleaching, and undesirable since one of the big advantages of mechanical pulp is the high yield of pulp based on wood used.

    Delignification of refiner mechanical pulps from Albizia

    The results showed that 8% NaOH + Na 2 S gave high yields (around 60%) with strength properties almost equal to those of kraft pulp (yield 45%) The results were also better than those obtained in previous tests of delignification of refiner mechanical pulp using the soda process.

    Bleaching of wood pulp

    The bleaching methods are similar for mechanical pulp in which the goal is to make the fibers brighter Bleaching chemical pulps Chemical pulps, such as those from the kraft process or sulfite pulping, contain much less lignin than mechanical pulps, (<5% compared to approximately 40%).

    Process for the delignification of unbleached chemical pulp

    Jul 31, 1984· The invention relates to a process for the delignification of unbleached chemical pulp, comprising the following stages: (a) oxidation of the unbleached pulp with a peroxide, in an alkaline medium with a % ratio of peroxide/pulp with respect to the Kappa index of said pulp which may vary between 001 and 01 and a pH kept at between 9 and 12, the said oxidation stage being followed by.

    Kraft process

    Kraft pulp is darker than other wood pulps, but it can be bleached to make very white pulp Fully bleached kraft pulp is used to make high quality paper where strength, whiteness and resistance to yellowing are important The kraft process can use a wider range of fiber sources than most other pulping process.