Latest revision as of 15:54, 12 January 2021

Infobox on Cellulose, chemical pulp
Example of Cellulose, chemical pulp
Facts
Origin	This table shows only a selection of the most important countries of origin and should not be thought of as exhaustive. Europe: Norway, Sweden, Finland, Portugal, Spain, France, Germany, Belgium, Luxembourg, Denmark, Greece, Great Britain, Ireland, Italy, Netherlands, Austria, Switzerland, Czech Republic, Poland, Turkey, former USSR Africa Asia: Japan America: Canada, USA, Brazil Australia: Australia
Stowage factor (in m³/t)	1.25 - 1.39 m3/t (loose bales) 1.25 - 1.39 m3/t (unitized bales) 1.45 - 1.56 m3/t (wet pulp) 1.65 - 1.90 m3/t (bales)
Humidity / moisture	Relative humidity: 60 - 65% (dry pulp) 85 - 90% (wet pulp) Water content 8 - 15% 5 - 10% (dry pulp) 40 - 55% (wet pulp) Maximum equilibrium moisture content: < 65% (dry pulp) 90% (wet pulp) Pulp is transported either as dry pulp or occasionally as wet pulp.
Ventilation	Recommended ventilation conditions: - for dry pulp: air exchange rate: 6 changes/hour (airing) - for wet pulp: air exchange rate: 10 - 20 changes/hour (airing) See text for more particulars
Risk factors	Chemical pulp is highly flammable, so protect from sparks, cigarette ends, fire and naked lights. Smoldering fires are also a risk.(see also text)

Cellulose, chemical pulp

Description

Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibres from wood, fibre crops or Waste Paper. Wood pulp is the most common raw material in papermaking.

There are three main chemical pulping processes.

The sulfite process dates back to the 1840's, and it was the dominant process before the second world war.
The kraft process, invented in the 1870's and first used in the 1890's, is now the most commonly practiced strategy.
Soda pulping is a specialty process used to pulp straws, bagasse, and hardwoods with high silicate content.

Mechanical pulping
There are two major mechanical pulps, thermo mechanical pulp (TMP) and groundwood pulp (GW).

In the TMP process, wood is chipped and then fed into large steam-heated refiners where the chips are squeezed and made into fibres between two steel discs.
In the groundwood process, debarked logs are fed into grinders where they are pressed against rotating stones and made into fibres. Mechanical pulping does not remove the lignin, so the yield is very high, >95%, but also causes paper made from this pulp to yellow and become brittle over time. Mechanical pulps have rather short fibre lengths and produce weak paper. Although large amounts of electrical energy are required to produce mechanical pulp, it costs less than chemical pulp.

Deinked pulp
Paper recycling processes can use either chemical or mechanical pulp. By mixing with water and applying mechanical action the hydrogen bonds in the paper can be broken and fibres separated again. Most recycled paper contains a proportion of virgin fibre in the interests of quality. Generally deinked pulp is of the same quality or lower than the collected paper it was made from.

There are three main classifications of recycled fibre:

Mill broke or internal mill waste – this incorporates any substandard or grade-change paper made within the paper mill which then goes back into the manufacturing system to be re-pulped back into paper. Such out-of-specification paper is not sold and is therefore often not classified as genuine reclaimed recycled fibre. However, most paper mills have been recycling their own waste fibre for many years, long before recycling became popular.
Preconsumer waste – this is offcuts and processing waste, such as guillotine trims and envelope blank waste. This waste is generated outside the paper mill and could potentially go to landfill, and is a genuine recycled fibre source. Also includes de-inked preconsumer (recycled material that has been printed but did not reach its intended end use, such as waste from printers and unsold publications).
Postconsumer waste – this is fibre from paper which has been used for its intended end use and would include office waste, magazine papers and newsprint. As the vast majority of this paper has been printed (either digitally or by more conventional means such as lithography or rotogravure), it will either be recycled as printed paper or go through a deinking process first.

Recycled papers can be made from 100% recycled materials or blended with virgin pulp. They are (generally) not as strong nor as bright as papers made from virgin pulp.
Besides the fibres, pulps may contain fillers such as chalk or China Clay, which improve the characteristics of the paper for printing or writing. Additives for sizing purposes may be mixed into the pulp and/or applied to the paper web later in the manufacturing process. The purpose of sizing is to establish the correct level of surface absorbency to suit the ink or paint.

Whiteness, strength and cleanness are the most important features in papermaking pulps.

Applications

Paper can be produced with a wide variety of properties, depending on its intended use.

For representing value: paper money, bank note, cheque, security, voucher and ticket.
For storing information: book, notebook, magazine, newspaper, art, zine, letter.
For personal use: diary, note to remind oneself, etc.; for temporary personal use: scratch paper.
For communication: between individuals and/or groups of people.
For packaging: corrugated box, paper bag, envelope, wrapping tissue, Charta emporetica and wallpaper.
For cleaning: toilet paper, handkerchiefs, paper towels, facial tissue and cat litter.
For construction: papier-mâché, origami, paper planes, quilling, paper honeycomb, used as a core material in composite materials, paper engineering, construction paper and paper clothing.
For other uses: emery paper, sandpaper, blotting paper, litmus paper, universal indicator paper, paper chromatography, electrical insulation paper and filter paper.

Shipment/storage

Woodpulp is shipped in (unitized) pressed bales (or rolls) and can be either 'dry' or 'wet'.
Wet pulp should not be stowed with goods liable to be damaged by drainage. Contact with water is liable to rust-stain the wrappers, but should not necessarily damage the contents other than causing possible bursting of the covering through expansion. Wrappers are usually of kraft paper and bound with wire.
The produce is subject to varying moisture content, which should be taken into account on assessment of any weight differences.
Contamination by any fibrous material may cause loss in value.
Wetting by salt water renders pulp unacceptable for use in the viscose process and any bale so wetted are mostly rejected, but may yet be used in papermaking.

Chemical pulp should be duly ventilated, to dissipate the production gases. Due to substantial water vapour release, wet pulp should be ventilated immediately at the beginning of the voyage. Where wet pulp is transported in standard containers, condensation will deposit on the internal container 'skins'.

Risk factors

- Self-heating / Spontaneous combustion
- Odor
- Contamination
- Mechanical influences
- Toxicity / Hazards to health
- Shrinkage/Shortage
- Insect infestation / Diseases

@@ Line 1: / Line 1: @@
 {{Infobox_Other_organic
-| image                               = cellulose.jpg
+| image                               = cellulose.JPG
-| origin                              =
+| origin                              = This table shows only a selection of the most important countries of origin and should not be thought of as exhaustive.<ul><li>Europe: Norway, Sweden, Finland, Portugal, Spain, France, Germany, Belgium, Luxembourg, Denmark, Greece, Great Britain, Ireland, Italy, Netherlands, Austria, Switzerland, Czech Republic, Poland, Turkey, former USSR</li><li>Africa</li><li>Asia: Japan</li><li>America: Canada, USA, Brazil</li><li>Australia: Australia</li></ul>
-| stowage factor                      =
+| stowage factor                      = <ul><li>1.25 - 1.39 m3/t (loose bales)</li><li>1.25 - 1.39 m3/t (unitized bales)</li><li>1.45 - 1.56 m3/t (wet pulp)</li><li>1.65 - 1.90 m3/t (bales)</li></ul>
-| humidity and moisture               =
+| humidity and moisture               = <ul><li>Relative humidity: 60 - 65% (dry pulp)</li><li>85 - 90% (wet pulp)</li><li>Water content 8 - 15%</li><li>5 - 10% (dry pulp)</li><li>40 - 55% (wet pulp)</li><li>Maximum equilibrium moisture content: < 65% (dry pulp)</li><li>90% (wet pulp)</li><li>Pulp is transported either as dry pulp or occasionally as wet pulp.</li></ul>
-| ventilation                         =
+| ventilation                         = Recommended ventilation conditions:<br>- for dry pulp: air exchange rate: 6 changes/hour (airing)<br>- for wet pulp: air exchange rate: 10 - 20 changes/hour (airing)<br>See text for more particulars
-| risk factors                        =
+| risk factors                        = Chemical pulp is highly flammable, so protect from sparks, cigarette ends, fire and naked lights. Smoldering fires are also a risk.(see also text)
 }}
-Description
+==Description==
-Chemical pulp is a man-made fiber of cellulose (C6H10O5)n, which is obtained from plant material (95% from wood) and is further processed predominantly in the paper industry, white pulp being used to produce printing and writing paper and brown pulp being used to produce paperboard and packing paper.
+Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose [[fibres]] from wood, fibre crops or [[Waste Paper]]. Wood pulp is the most common raw material in papermaking.
+<br><br>
+There are three main '''chemical pulping''' processes.<br>
+*The sulfite process dates back to the 1840's, and it was the dominant process before the second world war.<br>
+*The kraft process, invented in the 1870's and first used in the 1890's, is now the most commonly practiced strategy.<br>
+*[[Soda]] pulping is a specialty process used to pulp straws, bagasse, and hardwoods with high silicate content.<br><br>
+'''Mechanical pulping'''<br>
+There are two major mechanical pulps, thermo mechanical pulp (TMP) and groundwood pulp (GW).<br>
+*In the TMP process, wood is chipped and then fed into large steam-heated refiners where the chips are squeezed and made into [[fibres]] between two steel discs.<br>
+*In the groundwood process, debarked logs are fed into grinders where they are pressed against rotating [[stones]] and made into fibres. Mechanical pulping does not remove the lignin, so the yield is very high, >95%, but also causes paper made from this pulp to yellow and become brittle over time. Mechanical pulps have rather short fibre lengths and produce weak paper. Although large amounts of electrical energy are required to produce mechanical pulp, it costs less than chemical pulp.<br><br>
+'''Deinked pulp'''<br>
+Paper recycling processes can use either chemical or mechanical pulp. By mixing with water and applying mechanical action the hydrogen bonds in the paper can be broken and fibres separated again. Most recycled paper contains a proportion of virgin fibre in the interests of quality. Generally deinked pulp is of the same quality or lower than the collected paper it was made from.<br><br>
+There are three main classifications of recycled fibre:<br>
+*Mill broke or internal mill waste – this incorporates any substandard or grade-change paper made within the paper mill which then goes back into the manufacturing system to be re-pulped back into paper. Such out-of-specification paper is not sold and is therefore often not classified as genuine reclaimed recycled fibre. However, most paper mills have been recycling their own waste fibre for many years, long before recycling became popular.<br>
+*Preconsumer waste – this is offcuts and processing waste, such as guillotine trims and envelope blank waste. This waste is generated outside the paper mill and could potentially go to landfill, and is a genuine recycled fibre source. Also includes de-inked preconsumer (recycled material that has been printed but did not reach its intended end use, such as waste from printers and unsold publications).<br>
+*Postconsumer waste – this is fibre from paper which has been used for its intended end use and would include office waste, magazine papers and [[newsprint]]. As the vast majority of this paper has been printed (either digitally or by more conventional means such as lithography or rotogravure), it will either be recycled as printed paper or go through a deinking process first.<br><br>
+Recycled papers can be made from 100% recycled materials or blended with virgin pulp. They are (generally) not as strong nor as bright as papers made from virgin pulp.<br>
+Besides the fibres, pulps may contain fillers such as chalk or [[China Clay]], which improve the characteristics of the paper for printing or writing. Additives for sizing purposes may be mixed into the pulp and/or applied to the paper web later in the manufacturing process. The purpose of sizing is to establish the correct level of surface absorbency to suit the ink or paint.<br><br>
+Whiteness, strength and cleanness are the most important features in papermaking pulps.<br><br>
-Chemical pulp is subdivided into the following groups:
+==Applications==
+Paper can be produced with a wide variety of properties, depending on its intended use.<br><br>
+For representing value: paper money, bank note, cheque, security, voucher and ticket.<br>
+For storing information: book, notebook, magazine, newspaper, art, zine, letter.<br>
+For personal use: diary, note to remind oneself, etc.; for temporary personal use: scratch paper.<br>
+For communication: between individuals and/or groups of people.<br>
+For packaging: corrugated box, paper bag, envelope, wrapping tissue, Charta emporetica and wallpaper.<br>
+For cleaning: toilet paper, handkerchiefs, paper towels, facial tissue and cat litter.<br>
+For construction: papier-mâché, origami, paper planes, quilling, paper honeycomb, used as a core material in composite materials, paper engineering, construction paper and paper clothing.<br>
+For other uses: [[emery]] paper, sandpaper, blotting paper, litmus paper, universal indicator paper, paper chromatography, electrical insulation paper and filter paper.<br><br>
-•	sulfate pulp
+==Shipment/storage==
-•	sulfite pulp
+[[Woodpulp]] is shipped in (unitized) pressed bales (or rolls) and can be either 'dry' or 'wet'.<br>
-•	semichemical pulp
+Wet pulp should not be stowed with goods liable to be damaged by drainage. Contact with water is liable to rust-stain the wrappers, but should not necessarily damage the contents other than causing possible bursting of the covering through expansion. Wrappers are usually of kraft paper and bound with wire. <br>
-•	linters
+The produce is subject to varying moisture content, which should be taken into account on assessment of any weight differences.<br>
-•	mechanical pulp (MP, TMP, CTMP)
+Contamination by any fibrous material may cause loss in value. <br>
+Wetting by [[salt]] water renders pulp unacceptable for use in the viscose process and any bale so wetted are mostly rejected, but may yet be used in papermaking.<br><br>
-in each case fully bleached, semibleached or unbleached.
+Chemical pulp should be duly ventilated, to dissipate the production gases. Due to substantial water vapour release, wet pulp should be ventilated immediately at the beginning of the voyage. Where wet pulp is transported in standard containers, condensation will deposit on the internal container 'skins'.
-Cellulose raw materials include all cellulose-containing materials, such as wood, cotton, straw and other annual [[plants]]. Yield varies between 15 and 80% depending on the raw material and processing method used. During production, the cellulose fibers are separated from one another, either by pressure boiling (chemical pulping) or by mechanical comminution:
-. alkaline pressure boiling = sulfate pulp
-. acidic or neutral pressure boiling = a) sulfite pulp or b) semichemical pulp
-. mechanical comminution = mechanical pulp (MP and TMP)
-.CTMP is subjected initially to chemical/thermal pretreatment and is then mechanically comminuted, thereby assuming an intermediate position.
-Pressure boiling is followed by multi-stage bleaching. Unbleached chemical pulp is brown.
-Once dried, chemical pulp is sold commercially in sheets, pressed blocks or rolls.
-A distinction is drawn between papermaking pulps and special pulps. Special pulps are individually produced for their particular field of use, the important factor generally being chemical purity.
-The most important features of papermaking pulps are whiteness, strength and cleanness. In paper and [[cardboard]] production, papermaking pulps are either used in the pure state or mixed with secondary fibers.
-	Newsprint: more or less chemical pulp or mechanical pulp depending on waste paper content
-	Rotogravure paper: moderate to high chemical pulp content depending on quality
-	Hand-made paper: pure chemical pulp
-	Imitation parchment paper: pure sulfite pulp
-	Insulating paper: pure sulfate pulp, though mixtures with waste paper also possible
-	Kraft sack paper: sulfate pulp
-	Kraft packing paper: sulfate pulp, possibly also mixed with a small proportion of waste paper
-	Toilet paper: sulfite pulp, mixed with waste paper, 100% waste paper also possible
-Subject to compliance with the appropriate temperature and humidity/moisture conditions, duration of storage is not a limiting factor as regards transport and storage life.
-Applications
-Chemical pulps are used in the manufacture of paper and cardboard, among other things in the production of newsprint, rotogravure paper, hand-made paper, imitation parchment paper, insulating paper, kraft sack paper, kraft packing paper and toilet paper.
-Shipment/storage
-Chemical pulp is predominantly supplied in bales (e.g. 120 x 80 cm) weighing approx. 200 or 250 kg and rolls weighing 250 - 400 kg. According to [14], the bales may also weigh between 120 and 160 kg. Packaging generally consists of white or brown paper with a high cellulose content or of actual sheets of chemical pulp. Bales of chemical pulp are held together with wires or steel strapping. For ease of handling during loading and unloading, the individual bales are generally strapped together in units of 6 or 8 or even 12.
-Dry pulp may be transported in standard containers, subject to compliance with limits for water content of goods, packaging and flooring. If there is too much moisture present in the container, there is a risk that condensation water may form. Where containers are not watertight, there is a risk of ingress of moisture from outside (precipitation, seawater), leading to losses. It is therefore generally better to stow the containers below deck.
-Wet pulp is highly susceptible to losses in standard containers, as the high water content of the goods means that even slight temperature fluctuations may cause condensation water to form.
-The cargo must also be protected from moisture (rain, snow) during cargo handling (stow in hold or cover with tarpaulins in the case of truck and rail transport).
-During cargo handling, ensure that surfaces are clean. In addition, forklift trucks should be checked for hydraulic fluid and oil leaks and squeeze clamps should be clean.
-Papermaking pulp may also be stored in the open air in the short term, provided that it is adequately covered (tarpaulins) and the ground is clean. It is usually set down on squared lumber or pallets. Special pulp should be stored in sheds where possible.
-Chemical pulp is contaminated by fibrous materials and it is therefore important, where possible, to use wire rope or chains during cargo handling.
-Before the cargo is accepted, holds or containers must be absolutely clean (e.g. no patches of fat or oil) and dry, in particular in the case of viscose pulp (silk pulp).
-In the case of transport by ship, pipework must be leak-free, bilges must be inspected and hatch covers must be watertight. Where possible, dry pulp should not be stored on deck.
-Wet pulp may be transported on deck, but it must then be carefully protected from contact with seawater, to prevent blue discoloration. To minimize risks, it is therefore best to avoid stowage on deck.
-For stabilization purposes, cellulose packages may be provided with wooden frames. To prevent the packages from shifting and suffering damage during transport, the holds/containers should be tightly packed or any spaces that may remain should be filled with appropriate stowage material.
-Temperature
-Chemical pulp requires particular temperature, humidity/moisture and possibly [[ventilation]] conditions.
-Favorable travel temperature range: no lower limit - 30°C
-At higher temperatures, the risk of mold attack increases.
-Humidity/Moisture
-Designation 	                                    Humidity/water content
-Relative humidity 	                                    60 - 65% (dry pulp)
-- 90% (wet pulp)
-Water content 	                                     8 - 15%
-- 10% (dry pulp)
-- 55% (wet pulp)
-Maximum equilibrium moisture content 	< 65% (dry pulp)
-% (wet pulp)
-Pulp is transported either as dry pulp or occasionally as wet pulp.
-During cargo handling and transport, the cargo must be protected from all forms of moisture (seawater, rain and condensation water) and excessive relative humidity. Chemical pulp has a high swelling capacity and may increase in volume by > 50% if it absorbs moisture. Its suitability for transport may then be affected, the mixture ratio with other products changes and the risk of mold attack and mustiness increases, especially at elevated temperatures. Mold spoils the pulp and causes it to disintegrate. The action of seawater causes problems, since it leads to chemical reactions as well as rust spots. Technical developments in recent years mean that processing [[plants]] react more sensitively to seawater due to closed water circuits and because most operations are carried out at neutral pH. Seawater-sodden bales may be rejected.
-Wet pulp should not be stowed together with moisture-sensitive goods due to its high water content and its capacity to release water vapor.
-Cargo fires should be extinguished with CO2 or foam. If a fire is extinguished with water or in the event of water ingress, the swelling capacity of chemical pulp may result in severe damage to the structure of the vessel. For example, water ingress occurred when a ship loaded with pulp was in a collision. After only a short time, the pulp bales began to swell, forcing up the hatch covers. The cargo was so saturated and swollen with water that the central area of the ship became completely deformed. Unloading proved extremely difficult, with the severely swollen bales having to be wrenched out.
-Ventilation
-Chemical pulp requires particular temperature, humidity/moisture and possibly ventilation conditions.
-Recommended ventilation conditions:
-	for dry pulp: air exchange rate: 6 changes/hour (airing)
-	for wet pulp: air exchange rate: 10 - 20 changes/hour (airing)
-Chemical pulp must be carefully ventilated, to dissipate the gases generated in production. Wet pulp should be ventilated immediately after the start of the voyage, as considerable quantities of condensation may arise due to constant water vapor release. Where wet pulp is transported in standard containers, large amounts of condensation form on the container walls. At an equilibrium moisture content of 90%, a temperature difference of just 2°C between the pulp and the container wall is sufficient to cause condensation to form on the container walls, the container ceiling being most at risk of condensation.
-Biotic activity
-Chemical pulp displays 3rd order biotic activity.
-Chemical pulp is a product in which respiration processes are suspended, but in which biochemical, microbial and other decomposition processes still proceed.
-Gases
-Chemical pulp may release gases generated in production. Do not stow with chemicals ([[acids]], alkalies, gases), as explosive vapors may develop.
-Risk factors
-Self-heating / Spontaneous combustion
-Chemical pulp is highly flammable, so protect from sparks, cigarette ends, fire and naked lights. Smoldering fires are also a risk. Smoking is absolutely prohibited during cargo handling. Do not stow with chemicals (acids, alkalies, gases), as explosive vapors may develop. Cargo fires should be extinguished with CO2 or foam due to the swelling capacity of the cargo.
-Odor
-Active behavior 	Chemical pulp has a slight, unpleasant odor.
-Passive behavior 	Chemical pulp absorbs foreign odors easily. This risk is particularly significant in the case of materials to be used for foodstuffs (e.g. coffee filters).
-Contamination
-Active behavior 	Chemical pulp does not cause contamination.
-Passive behavior 	Chemical pulp is contaminated in particular by coal, grain, [[fats]]/oils and fibrous material. Contamination by fats/oil often results in the entire cargo being lost, as the pulp becomes unfit for further processing. Do not accept any bales which are dirty or are strapped with rusty steel straps.
-Chemical pulp is supplied as a finished auxiliary or end product for further processing. Contamination caused by external dirt (on the packaging) need not be considered serious as long as it is certain that the product itself is not contaminated. Internal contamination disrupts production operations. Bitumen and plastic pellets are extremely deleterious, but grain, wood splinters and other small items may also [[lead]] to production defects. The former contaminants bring with them the very real risk of consequential losses amounting to many times the value of the product (unreusable waste, machine down-time and possibly even damage to the wire and cylinder).
-Mechanical influences
-Improper handling, e.g. incorrect positioning of the clamps or bumping, may result in mechanical damage to the pulp bales. To prevent this damage, the bales are wrapped in protective sheets.
-Toxicity / Hazards to health
-Gases generated during the production of chemical pulp may present a risk to health when released.
-Shrinkage/Shortage
-Unclearly marked bales may result in losses of volume due to incorrect delivery.
-Insect infestation / Diseases
-Chemical pulp may be attacked and destroyed by microbes and insects, especially moths. The risk of moth infestation increases if the bales are contaminated or stowed near [[wool]] bales or if their packaging consists of material susceptible to moth attack
-Note:
-(Source including Transport Information Service of the GDV)
+==Risk factors==
+- Self-heating / Spontaneous combustion<br>
+- Odor<br>
+- Contamination<br>
+- Mechanical influences<br>
+- Toxicity / Hazards to health<br>
+- Shrinkage/Shortage<br>
+- Insect infestation / Diseases<br>
+<br><br>
 [[Category: Products]]
-[[Category: Other organic material]]
+[[Category: Forest products]]

Difference between revisions of "Cellulose, chemical pulp"

Latest revision as of 15:54, 12 January 2021

Cellulose, chemical pulp

Contents

Description

Applications

Shipment/storage

Risk factors

Categories

Products A-Z

Difference between revisions of "Cellulose, chemical pulp"

Latest revision as of 15:54, 12 January 2021

Cellulose, chemical pulp

Contents

Description

Applications

Shipment/storage

Risk factors