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{{Short description|Science of paper and papermaking}}
{{Use mdy dates|date=February 2014}}
[[File:InternationalPaper6413.jpg|250px|thumb|right|[[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.<ref name=autogenerated1>{{Cite web |url=http://www.industrysolutions.siemens.com/paper/en/index.htm |title=Siemens AG. Pulp and Paper Technologies. |publisher=[[Siemens]] |access-date=November 23, 2010 |archive-url=https://web.archive.org/web/20101106134519/http://www.industrysolutions.siemens.com/paper/EN/index.htm |archive-date=November 6, 2010 |url-status=dead }}</ref> The field applies various principles in [[process engineering]] and [[unit operations]] to the manufacture of [[paper]], [[paper chemicals|chemicals]], [[energy]] and related materials. The following timeline shows some of the key steps in the development of the science of chemical and bioprocess engineering:<ref>[http://www.pafko.com/history/h_intro.html  History of Chemical Engineering] – at North Carolina State University (and in general).</ref>

From a heritage perspective, the field encompasses the design and analysis of a wide variety of thermal, chemical and biochemical [[unit operations]] employed in the manufacture of pulp and paper, and addresses the preparation of its raw materials from trees or other natural resources via a [[Wood pulp|pulp]]ing process, chemical and mechanical pretreatment of these recovered [[biopolymer]] (e.g. principally, although not solely, [[cellulose]]-based) fibers in a fluid suspension, the high-speed forming and initial dewatering of a non-woven web, the development of bulk sheet properties via control of energy and mass transfer operations, as well as post-treatment of the sheet with coating, calendering, and other chemical and mechanical processes.<ref name=autogenerated1 />

==Applications==
Today, the field of paper and chemical engineering is applied to the manufacture of a wide variety of products. The forestry and biology, chemical science, (bio)[[chemical industry]] scope manufactures organic and [[agrochemicals]] (fertilizers, insecticides, herbicides), [[oleochemicals]], fragrances and flavors, food, [[Fodder|feed]], [[pharmaceuticals]], [[nutraceuticals]], [[chemicals]], [[polymers]] and power from biological materials.

The resulting products of paper engineering including paper, cardboard, and various paper derivatives are widely used in everyday life. In addition to being a subset of chemical engineering, the field of paper engineering is closely linked to [[forest management]], product [[recycling]], and the mass production of paper – based media.

==Methods==

===Mechanical pulping===
In the process of mechanical pulping, "grinding" and "refining" are the two main methods used to create the pulp. Grinding is the method of pressing logs and chips against a turning stone to produce fibers. Refiner pulping is treating wood chips with chemicals or heat and then crushing the objects between two disks, one or both of which are rotating. There are four main types of refiner pulping, which includes refiner mechanical pulping, thermo-mechanical pulping, chemi-mechanical pulping, and chemithermomechanical pulping.<ref>{{cite web |url=http://www.cfr.washington.edu/classes.pse.476/Powerpoint/Powerpoint-Renata/pse%20476-2%20mechanical%20pulping.ppt |title=Pulping and Bleaching |author=R. Gustafson |date=n.d. |publisher=University of Washington |access-date=November 23, 2010 |archive-url=https://web.archive.org/web/20110114091135/http://www.cfr.washington.edu/classes.pse.476/Powerpoint/Powerpoint-Renata/pse%20476-2%20mechanical%20pulping.ppt |archive-date=January 14, 2011 |url-status=dead }}</ref> Further descriptions of each process are contained in this link:<ref>{{Cite web |url=http://www.cfr.washington.edu/classes.pse.476/Powerpoint/Powerpoint-Renata/pse%20476-2%20mechanical%20pulping.ppt |title=Archived copy |access-date=November 24, 2010 |archive-url=https://web.archive.org/web/20110114091135/http://www.cfr.washington.edu/classes.pse.476/Powerpoint/Powerpoint-Renata/pse%20476-2%20mechanical%20pulping.ppt |archive-date=January 14, 2011 |url-status=dead }}</ref>
Mechanical pulping, when compared to chemical pulping, is relatively inexpensive and has a high pulp yield (85–95%). However, the paper created is generally weak since it retains the lignin.<ref name=autogenerated1 />

===Chemical pulping===
The process of [[chemical pulping]] is used to chemically disband the [[lignin]] found in the cell walls of the material undergoing the process. After the [[cellulose]] fibers are separated from the lignin, a pulp is created which can then be treated to create durable paper, boxes, and corrugated cardboard. Chemical pulping can be characterized by two main methods: sulfate ([[Kraft process]]) pulping and sulfite pulping, and these two methods have different benefits. Sulfate pulping can be performed on a wide range of tree varieties and results in the creation of a strong type of paper. Conversely, sulfite pulping results in a higher volume of pulp which is easier to bleach and process. However, sulfate pulping is more widely used since the product is more durable and the chemicals used in the process can be recovered, thus resulting in minimal environmental pollution.<ref>{{cite web|url=http://www.ecy.wa.gov/programs/air/pdfs/pulpmil3.pdf  |title=Chemical Pulp Mills |author= Washington State Department of Ecology |date=n.d. |access-date=November 23, 2010 }}</ref>

===Further pulp processing===
{{Main|Paper machine}}

The pulp is then processed through an apparatus which renders the pulp as a mesh of fibers. This fiber network is then pressed to remove all water contents, and the paper is subsequently dried to remove all traces of moisture.

===Finishing===
{{Main|Paper}}

After the above processes have been completed, the resulting paper is coated with a minuscule amount of [[china clay]] or [[calcium carbonate]] to modify the surface, and the paper is then re-sized depending on its intended purpose.

===Product recycling ===
{{Main|Paper recycling}}

Generally, the material to be recycled first undergoes mechanical or chemical pulping to render it in pulp form. The resulting pulp is then processed in the same way normal pulp is processed; however, original fiber is sometimes added to enhance the quality and appearance of the product.

==Related fields and topics==
{{Prose|section|date=August 2014}}
Today, the field of paper and bioprocess engineering is a diverse one, covering areas from [[biotechnology]] and [[nanotechnology]] to [[electricity generation]].
[[File:SantaFeRecoveryBoiler.JPG|thumb|500px|Paper engineers design, construct and operate plants]]
[[File:Cellulose strand.svg|thumb|[[Cellulose]] is a natural biopolymer]]
{{div col|colwidth=22em}}
*[[Agricultural engineering]]
*[[Biomolecular engineering]]
*[[Biochemical engineering]]
*[[Biological engineering]]
*[[Chemical process modeling]]
*[[Chemical engineering]]
*[[Chemical reactor]]
*[[Computational fluid dynamics]]
*[[Corrosion engineering]]
*[[Environmental engineering]]
*[[Fluid dynamics]]
*[[Food engineering]]
*[[Forest engineering]]
*[[Heat transfer]]
*[[Mass transfer]]
*[[Materials science]]
*[[Microfluidics]]
*[[Nanotechnology]]
*[[Natural environment]]
*[[Polymer]]s
*[[Process control]]
*[[Process design (chemical engineering)|Process design]]
*[[Process development]]
*[[Safety engineering]]
*[[Separation process]]es
*[[Textile engineering]]
*[[Thermodynamics]]
*[[Transport phenomena]]
*[[Unit operations]]
*[[Water technology]]
{{div col end}}

==Colleges and universities==
{{Prose|section|date=August 2014}}
Generally offered as a specialization within chemical engineering:<ref>{{cite web |url=http://cnr.ncsu.edu/fb/futureundergrads/psedegrees.html |title=Paper Science & Engineering Degrees |access-date=2010-04-21 |url-status=dead |archive-url=https://web.archive.org/web/20100609160853/http://cnr.ncsu.edu/fb/futureundergrads/psedegrees.html |archive-date=June 9, 2010 |df=mdy-all }}:</ref>

*United States
**[[Auburn University]]
**[[Georgia Institute of Technology]]
**[[Miami University]]
**[[North Carolina State University]]
**[[SUNY ESF]]
**[[University of Maine]]
**[[University of Minnesota]]
**[[University of Washington]]
**[[University of Wisconsin - Stevens Point]]
**[[Western Michigan University]]
*Canada
**[[École Polytechnique de Montréal]]
**[[McGill University]]
**[[McMaster University]]
**[[University of British Columbia]]
**[[University of New Brunswick]]
**[[Université du Québec à Trois-Rivières]]
**[[University of Toronto]]
*Europe
**[[Universitat Politècnica de Catalunya]], Spain
**[[Darmstadt University of Technology]], Germany
**[[Dresden University of Technology]], Germany
**[[Grenoble INP]], France
**[[Helsinki University of Technology]], Finland
**[[Lund Institute of Technology]], Sweden
**[[Tampere University of Technology]], Finland
**[[Technische Universitat Graz]], Austria
**[[Saint Petersburg State Technological University of Plant Polymers]], Russia
**[[Technical University of Łódź]], Poland
**[[University of Manchester]], UK
**[[Åbo Akademi University]], Finland
*Asia-Pacific
**[[Akademi Teknologi Pulp dan Kertas]]
**[[Monash University]]<ref>{{cite web| url=http://www.eng.monash.edu.au/chemical/research/centres/appi/ | title=Australian Pulp and Paper Institute (APPI) | publisher=Monash University| access-date=July 29, 2010}}</ref>
**[[Indian Institute of Technology, Roorkee]]
**[[South China University of Technology]]

==See also==
{{Main|Outline of chemical engineering}}
{{Portal|Chemistry|Engineering}}
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* [[Paper folding]]
* [[Chemical engineer]]
* [[List of chemical engineers|List of notable chemical engineers]]
* [[List of chemical engineering societies]]
* [[American Institute of Chemical Engineers]] (AIChE)
* [[Chemistry]] and [[engineering]]
*[http://www.sust.edu/cep/Research/research.htm Chemical engineering and polymer science]
* [[Institution of Chemical Engineers]] (IChemE)
* ''[[Food and Bioprocess Technology]]''
* [[Contemporary food engineering]]
* [[Education for chemical engineers]]
* [[English engineering units]]
* [[Process design (chemical engineering)]]
* [[List of chemical process simulators]]
* [[List of dynamic process simulators]]
<!-- * 35 Chemical engineering equipment design thesis books[http://www.sbioinformatics.com/design_thesis/design-2520thesis.htm] -->
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==References==
{{Reflist}}

{{Paper}}

{{DEFAULTSORT:Paper and Bioprocess Engineering}}
[[Category:Engineering disciplines]]
[[Category:Pulp and paper industry]]
[[Category:Process engineering]]