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A pulp mill is a manufacturing facility that converts wood chips or other plant fiber sources into a thick fiber board which can be shipped to a paper mill for further processing. Pulp can be manufactured using mechanical, semi-chemical, or fully chemical methods ( kraft and sulfite processes). [ 1 ]
Chemical pulping involves dissolving lignin in order to extract the cellulose from the wood fiber. The different processes of chemical pulping include the Kraft process, which uses caustic soda and sodium sulfide and is the most common; alternatively, the use of sulfurous acid is known as the sulfite process, the neutral sulfite semichemical is treated as a third process separate from sulfite ...
International Paper: Kraft paper mill Woodchips for paper production. The kraft process (also known as kraft pulping or sulfate process) is a process for conversion of wood into wood pulp, which consists of almost pure cellulose fibres, the main component of paper.
Chemical pulp mills, especially kraft mills, are energy self-sufficient and very nearly closed cycle with respect to inorganic chemicals. Bleaching with chlorine produces large amounts of organochlorine compounds, including polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs).
A typical refiner pulp can require 2000 kWh/mass ton pulp. [1] A larger mechanical pulp and paper mill can, including the paper production, consume 200-300 MW electricity. The chemical pulping processes can often generate enough energy (steam and electricity) to make the mill energy self-sufficient.
Chemical processes quickly followed, first with Julius Roth's use of sulfurous acid to treat wood in 1857, followed by Benjamin Chew Tilghman's US patent on the use of calcium bisulfite, Ca(HSO 3) 2, to pulp wood in 1867. [3] Almost a decade later in 1874 the first commercial sulfite pulp mill was built in Sweden.
Pulp mills have used black liquor as an energy source since at least the 1930s. [8] Most kraft pulp mills use recovery boilers to recover and burn much of the black liquor they produce, generating steam and recovering the cooking chemicals (sodium hydroxide and sodium sulfide used to separate lignin from the cellulose fibres needed for ...
International Paper: Kraft paper mill. Paper engineering is a branch of engineering that deals with the usage of physical science (e.g. chemistry and physics) and life sciences (e.g. biology and biochemistry) in conjunction with mathematics as applied to the converting of raw materials into useful paper products and co-products. [1]