Tiếng Việt English China
牛皮 纸
双挂纸 (Duplex)

Hot news
» 美卓矿机(衢州)有限公司成立两周年
» 美卓在芬兰Neste波尔沃炼油厂大修中提高了阀门可用性
» 美卓连续四次荣获智力矿山最佳供应商殊荣
» 美卓诺德伯格GP220圆锥破碎机提高月产量114%
» 美卓创新的深冷蝶阀马帕克BWX系列
» 美卓推出PREMIER与COMPACT系列振动筛,提供多用途解决方案
    要闻和事件 » 目录 UKp - - - paper - Magazine Roll-up Crafts - How to Make a Vase out of Magazines - How To Make Paper - How To Make Paper - How to on Handmade Paper - Exhibit shows paper to be anything but plain - Timerman: “The pulp mill of Colonia respects the treaty of Río de la Plata” - What is Kraft Paper? - Thurso, QC, pulp mill restart will restore large pulpwood, biomass demand - Timber management company enters biomass supply realm - Giant miscanthus grass studied for biofuel production - AbitibiBowater studies $51M power generation project in Ontario - Alabama Power partners with lumber producer Westervelt to make biomass energy - Clearwater using wood slash for biofuel at Idaho mill [From the web] - Wisconsin legislature advances logging equipment tax relief bill - New York coal power plant to co-fire with wood - BC government issues review of busy 2009 wildfire season - USDA announces new subsidies and loans for biomass development - Quebec wood energy plant expands effort to use fuel from old bark piles - Bids come in to convert IP’s Franklin mill to energy plant - Graphic Packaging to go off the grid with 100% biomass in Georgia - Electrabel more than quadruples wood biomass use at Netherlands power plant - Idle QC pulp mill to become pellet plant - Clenergen, Honeywell to test dedicated wood biomass crops for oil production - Siemens awarded contract for biomass-powered turbine at paper mill in UK - May 5, 2010 Clenergen secures land lease in India to cultivate dedicated biomass crops - The RISI Top 50 Power List - APP applies advanced wastewater treatment to enhance environmental performance - New York coal power plant to co-fire with wood - Demand drop caused IP Franklin mill shutdown [From the web] - Paperlinx to close Burnie Mill in Tasmania and become merchant only - Billerud's Skärblacka paper mill faces production shutdown due to Swedish paper union strike - Taiwan Pulp & Paper halts production due to earthquake - Asia Pulp & Paper Disappointed in Subsidy Case Findings - Metso to deliver defibrator system to Siempelkamp for Indonesia - 2010 AF&PA Community Recycling Award Presented to Virginia Beach, Virginia - Process for manufacturing bleached pulp with reduced chloride production - £350,000 kit investment for new finishing startup - APP claims new study proves its green credentials - Pulp giants to boost capacit) - Paper - How To Recycle Paper (homemade Letter Paper) - Paper recycling information sheet - Recycling Cardboard and Paper - Why Recycle Paper? - CHINA - TEND YOUR TALENT ‘SEEDLINGS’ - THE PRIDE OF ESTONIA - WORLDWIDE NEWS - Wood pulp - Pulp mill - Wood pulp is made in several stages: - Paper history - 3000BC - Paper history - AD 105 - Paper history - AD 610 - Paper history - 14th CENTURY - Paper history - 16th CENTURY - Paper history - 17th CENTURY - Paper history - 18th CENTURY - Paper history - 19th & 20th CENTURY - Paper history - 2000 & BEYOND -
Share |
Pulp mill

 Milling process

The process begins at the chip pile, where planer wood chips and sawmill chips may be stored for one to two months for 'seasoning' for mechanical pulping.

The wood from the trees contains three main components, in addition to water. The components are cellulose polymer fibres, which are the desired material for papermaking, lignin, which is a three-dimensional polymer that cements the cellulose fibres together to produce the strength inherent in a tree or in lumber, and so-called hemicelluloses, which are shorter polymer chains of sugars. The aim of chemical pulping is to separate the useful cellulose fibres from the lignin and hemicelluloses. The balance is to remove all of the lignin without reducing the strength of the cellulose fibres by cutting them.

Chemical pulping processes such as the Kraft (or sulphate) process and the sulphite process reduce much of the hemicelluloses and lignin. The kraft process is more successful than the sulphite at allowing the strength of the cellulose fibres to remain. The chemical pulping processes use a combination of high temperature and alkaline (kraft) or acidic (sulphite) chemicals to break the chemical bonds of the lignin.

The various mechanical pulping methods, such as groundwood (GW) and refiner mechanical (RMP) pulping, physically tear the cellulose fibres one from another. Much of the lignin remains adhering to the fibres. Strength is impaired because the fibres may be cut.

There are a number of related hybrid pulping methods that use a combination of chemical and thermal treatment to begin an abbreviated chemical pulping process, followed immediately by a mechanical treatment to separate the fibres. These hybrid methods include thermomechanical pulping (TMP) and chemithermomechanical pulping (CTMP). The chemical and thermal treatments reduce the amount of energy subsequently required by the mechanical treatment, and also reduce the amount of strength loss suffered by the fibres.

The chips are brought into the screening section of the mill, where they are sorted and screened of sawdust. The oversize chips are rechipped or used as fuel. Once screened, the chips make their way to the Digester where they are mixed into the large vessel with sodium hydroxide and sodium sulphide liquids and heated with steam from the mill boiler.

After several hours in the digester, the chips break down into a thick porridge-like consistency and the chips are squeezed from the outlet of the digester through an airlock. The sudden change in pressure causes the chips to expand in a popcorn-like fashion, thereby separating the wood fibres further. The resulting fibre suspension in water solution is termed pulp or stock.

The wood fibres are washed clean of all chemical residue, which is recovered and recycled in the plant. The fibre, now known as 'stock' can be bleached or left unbleached. The stock is sprayed onto the pulp machine wire and the water is drained and the pulp is pressed prior to passing into the machine-room drier. The fibres at this point have been allowed to reorient themselves into non linear patterns. The pressing and drying of these fibres in this state creates a strong linking bond between them not unlike a mesh. The dried pulp is cut, stacked and bailed at the layboy, on the drier outlet.

The pulp may then be loaded into rail car, truck, or seagoing vessel.


Online: 25
Today: 990
Yesterday: 1.917
This month: 44.893
Last month: 67.764
Counter: 19.164.270
  Copyright © 2006 ASIA INVESTMENT JSC. All rights reserved.