10.2 Chemical Wood Pulping
10.2 Chemical Wood Pulping 10.2.1 General Chemical wood pulping involves the extraction of cellulose from wood by dissolving the lignin that binds the cellulose fibers together. The 4 processes principally used in chemical pulping are kraft, sulfite, neutral sulfite semichemical (NSSC), and soda. The first 3 display the greatest potential for ...
Sulfite process
The sulfite process produces wood pulp that is almost pure cellulose fibers by treating wood chips with solutions of sulfite and bisulfite ions. These chemicals cleave the bonds between the cellulose and lignin components of the lignocellulose. A variety of sulfite/bisulfite salts are used, including sodium (Na +), calcium (Ca 2+), potassium (K +), …
2.D.1 Pulp and paper
• Kraft (sulphate) pulping is the most widely used pulping process and is typically used to produce strong paper products. The Kraft pulping process includes wood (or other cellulose-bearing materials) digestion in a water solution of sodium sulphite and sodium hydroxide, pulp washing, bleaching, chemical recovery and by-product recovery.
Sulfate
The sulfate or sulphate ion is a polyatomic anion with the empirical formula SO 2 ... 4 ·24H 2 O, figured in the development of the chemical industry. Environmental effects. Sulfates occur as microscopic particles resulting from fossil fuel and biomass combustion. They increase the acidity of the atmosphere and form acid rain. The ...
Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp …
The chemical recovery process at pulp mills involves the recovery of chemicals in the spent cooking liquor, reconstitution of those chemicals, and the generation of energy from the incineration of the organic residuals. This subpart regulates the emissions from the pulp mill combustion sources, which are recovery furnaces, smelt …
Nickel and cobalt precipitation from sulphate leach
The presence of nickel and cobalt in the precipitate was assumed in two chemical forms, one as sulphate resulting from chemical adsorption, which is predominant below pH 5.7; and also as the ...
Black Liquor Oxidation as a Means of Efficient Chemical …
Chemical Recovery in Paper Mills. Eng. Proc. 2023, 37, 26.https:// ... Abstract: The chemical recovery cycle is essential for every pulp mill producing pulp via chemical pulping. The purpose of this cycle is to recover inorganic chemicals used for pulping that can facilitate ... be 98–99%, and the amount of sulphide converted into …
Smarter Chemical Recovery in Pulping Facilities | Veolia …
Authors: Michael Begley and Scott Silverstein, Veolia Water Technologies Featured in Chemical Engineering Magazine - March 1, 2022. The emergence of new products and markets is driving a global renaissance of the pulp-and-paper industry due to increased global demand for cardboard and paper packaging products, as well as the rise in the …
A review of the traditional pulping methods and the …
The paper strength and durability gained are at an expense of pulp yield with the chemical pulping process producing pulp yields which are nearly half those of mechanical pulping methods (40–55% yield) [43, 44]. There are two major chemical pulping processes currently in use, that is, Kraft (sulfate) pulping and sulfite pulping.
What is Chemical Pulp? (with picture)
There are two widely recognized processes for producing chemical pulp. One is known as sulfate pulping. The other is known as sulfite pulping. The major differences between these are the chemicals used, the quality of paper produced, and the economy of chemical recovery.
Understanding the Properties and Characteristics of Sulphate Pulp …
Sulphate pulp, also known as Kraft pulp, is a type of chemical pulp that is widely used in various industrial applications. It is made by the Kraft process, which involves the chemical digestion of wood chips with a mixture of sodium hydroxide and sodium sulphide.The resulting pulp has unique physical and chemical properties that make it an ideal choice …
Improved Chemical Recovery Efficiency inKraft PulpMills …
chemical losses from such units, for the same type of pulp, mainly depend upon No. of washing stages and dilution factor, employed. Other process vari-ables like temperature of wash water, vat consistency, vacuum etc. are also important. The washing losses in our country generally range from 20-25 Kg. of Na2S04 per tonne of pulp.
Chemical Recovery at The Sulphate Pulp Mill005
Chemical Recovery at the Sulphate Pulp Mill005 - Free download as PDF File (.pdf), Text File (.txt) or read online for free. The sulphate process is based on a cycle principle ensuring that the raw materials are used efficiently and that emissions and energy losses are minimized. The black liquor from the washing department has a dry solids content of …
The Effect of Dead Load Chemicals in the Kraft Pulping …
chemical recovery The kraft pulping process is based on the use of sodium hydroxide (NaOH) and sodium sulfide (Na 2 S) to con-vert wood to pulp. Dissolved wood substances and spent inorganic chemicals are washed from the pulp to produce black liquor, which can be concentrated and burned in the recovery cycle. The recovered inorganic chemicals
Chemical recovery systems for paper | Eco-friendly practices
Chemical recovery allows pulp mills to make the most of their resources. By recycling and reusing chemicals, mills can reduce the need to purchase expensive new chemicals, thereby cutting production costs. 2. Minimizing Waste. Chemical recovery significantly reduces the amount of waste generated by pulp mills.
Sulphate removal/recovery
Sulphate is one of the world's most widely used commodities. Although not very toxic, excessive discharge of sulphate can lead to ecological problems. Used water in the chemical industry often contains organic material in addition to sulphate. SULFATEQ™ can remove both in the same process, whilst producing elemental sulphur that can be ...
Chemical Recovery In Pulp And Paper Industry
Chemical Recovery In Pulp And Paper Industry Feed: 162 - Date: 9/30/2018 - Views: 1,088 ... Sulfate or Kraft pulping is the main pulping process was invented in Germany in 1884 and remains the dominating technology today. Usually known as "kraft pulping" which relies on a combination of heat, chemicals and mechanical …
Chloride and potassium removal processes for kraft pulp …
The filtrate which is rich in sodium sulphate is recycled in the chemical recovery loop. In such mills, there may be no need for using membrane filtration based processes (Tran and Earl, 1990) . ...
Controlling sulfidity in a modern kraft pulp mill, case study
Controlling sulfidity in a modern kraft pulp mill, case study. May 8, 2018. Many years ago, the kraft pulping liquor circuit used sodium sulfate salt as the main make-up source of cooking chemicals. The make-up chemical has given its name to the process in many languages. Back then, the sulfidity reached an equilibrium level that was …
Pulping
At present, the chemical pulping industry uses primarily sulfate pulping (Kraft pulping), sulfite pulping, or soda pulping processes for separating lignin on an industrial scale from wood and from some annual plants, such as bagasse, different straw species, flax, hemp, and bamboo. During the respective process, the different lignin types are recovered from …
Chemical Pulping Methods
Sulfate or Kraft pulping, acid and alkaline sulfite pulping, neutral sulfite semi-chemical (NSSC) pulping, and soda pulping are the currently available techniques. Kraft pulping has led the way in chemical pulping because it can make useable pulps from any type of wood, recovers energy and chemicals from used pulping liquor better than any ...
A system analysis of the chemical recovery plant of the …
Nordic Pulp and Paper Research Journal no. 411 989 263 1180 ADDRESSES OF THE AUTHORS: H. Theliander, De- partment of Chemical Engineering Design, Chalmers Unj- versity of Technology, S-412 96 Gothenburg, Sweden. 0. Aksnes: MO and Domsjo AB, Husum sulphate mill, S- 890 35 Husum, Sweden.
Improved Chemical Recovery Efficiency inKraft …
chemical losses from such units, for the same type of pulp, mainly depend upon No. of washing stages and dilution factor, employed. Other process vari-ables like temperature …
Evaluating chemical-, mechanical-, and bio-pulping …
Chemical Pulping Processes. The following discussion centers on chemical pulping processes, which supply more than two tive thirds of world's wood pulp. The most widely used chemical pulping process in papermaking is the kraft, or sulfate, process. Other chemical-pulping process (mainly using acid sulfite and soda) are
chemical recovery at the sulphate pulp mill005
Chemical Recovery at the Sulphate Pulp Mill. During the cook the cooking chemicals have been transformed. Recovery of these chemicals is absolutely essential for both environmental and economic reasons. This is accomplished in the chemical recovery department at the mill.
ENVIRONMENTAL ASPECTS OF THE PULP AND PAPER …
significant with chemical pulping processes than with mechanical processes. Since over 65 percent of the total pulp produced is composed of kraft pulp, the main impact on the environment is from chemical pulping. 2.1. Kraft (Sulphate) Pulping: This process, first used in 1879, was a modification of the caustic soda
Kraft pulp mill dregs and grits as permeable reactive barrier for
Sulfate retention was effective at pH below 5, with an efficiency of 79% and 89% for dregs and grits, respectively. ... in the recovery of the chemical liquor from kraft pulp mills have usually ...
Consequential life cycle assessment of kraft lignin recovery …
If only the market pulp is considered (90 % of which is sulphate pulp), the scenario is quite different. In fact, European production is lower than annual consumption (slightly increased in recent years) (CEPI, 2022). In most pulp mills the recovery boiler operates at maximum capacity and becomes the bottleneck (Moretti et al., 2021). …
Sulfate Pulp
Amino and Furan Resins. Christopher C. Ibeh, in Handbook of Thermoset Plastics (Second Edition), 1998 Paper treatment and coating. Enhancing strength is the major reason for impregnating paper with resin. Sulfate pulp paper, Kraft paper, and unbleached sulfite cellulose paper are impregnated with amino resins typically at a pH of about 4 to 5. Urea …
The role of sulfidity during kraft pulping
The history of the kraft pulping process is obscure, and few patents and stories try to explain the origin of this chemical pulping process. The story that most likely explain its origin goes back to the 1870s in a soda mill, where a chemical recovery plant operator made a mistake in the process of adding sodium carbonate (Na 2 CO 3) for …