CH0204 Organic Chemical Technology
Lecture 6
Chapter 1 Natural Products
Balasubramanian S Assistant Professor (OG) Department of Chemical Engineering
Balasubramanian S 1 Overview of topics
Chapter 1 NATURAL PRODUCTS
2 Sugar
3 Starch and its deriva ves
Balasubramanian S 2 Overview of topics
Chapter 1 NATURAL PRODUCTS
1 Pulp and Paper
2 Sugar
3 Starch and its deriva ves
Balasubramanian S 3 Pulp and Paper
Defini ons History of Pulp and Paper Global Pulp and Paper industries scenario Indian Pulp and Paper Industries scenario Raw materials Manufacture of Pulp and paper Process descrip on Paper products
Balasubramanian S 4 Pulp and Paper – Raw materials Pulping
Paper produc on requires a disintegra on of the bulky fibrous material to individual or small agglomerate fibers. This is called Pulping.
The requirement of a good raw material for pulp and paper produc on,
1. The ideal fiber for high grade paper should be long i.e. fiber must be long 2. High in cellulose content 3. Low in lignin content
Balasubramanian S 5 Pulp and Paper – Raw materials
Coniferous Woods which So wood includes, redwood, spruce, pines and so on.
Comes from deciduous trees which incudes Hard Wood Eucalyptus, Pinus, Rubber plants and so on
Munji, Sabai grass, and Raw material Grasses and reeds Bamboo vari es
Rice, Wheat, Barley, Straws bagasse and so on
Co on linters are fine, silky fibers which adhere Co on linters to the seeds of the co on plant a er ginning.
Balasubramanian S 6 Pulp and Paper – Raw materials
So wood
Coniferous Woods which includes, redwood, spruce, pines and so on.
Balasubramanian S 7 Pulp and Paper – Raw materials
Hard Wood
Comes from deciduous trees which incudes Eucalyptus, Rubber plants and so on
Balasubramanian S 8 Pulp and Paper – Raw materials
Grasses and reeds
Munji, Sabai grass, and Bamboo vari es
Balasubramanian S 9 Pulp and Paper – Raw materials
Straws
Rice, Wheat, bagasse and so on
Balasubramanian S 10 Pulp and Paper – Raw materials
Co on linters
Co on linters are fine, silky fibers which adhere to the seeds of the co on plant a er ginning.
Balasubramanian S 11 Pulp and Paper – Raw materials Wood
Balasubramanian S 12 Pulp and Paper – Raw materials
Array of high molecular weight glucose polymer chains, currently more valuable as fiber
Binder for cellulose fiber and it is a complex amorphous poly phenol polymer
Cellulose
Hemi Cellulose
Disordered array of several sugar polymers Balasubramanian S 13 Pulp and Paper
Defini ons History of Pulp and Paper Global Pulp and Paper industries scenario Indian Pulp and Paper Industries scenario Raw materials Manufacture of Pulp and paper Process descrip on Paper products
Balasubramanian S 14 Pulp and Paper – Pulping Methods
Mechanical Sulfate (or) Kra Process Pulping Chemical Sulfite Semi Chemical
Balasubramanian S 15 Pulp and Paper – Pulping Methods
Mechanical Chemical Semi chemical Wood is debarked and it The cellulose from the Wood chips are given with mild chemical is mechanically wood is freed from treatment with dilute mixture; of sulfite, shredded to form fibers. lignin by chemical sulfate, caus c soda, and or soda ash reagents. reagents. Suitable for the Pulp produced has high The wood is so ened sufficiently to allow produc on of strength and fine mechanical separa on of fibers without newsprint, toweling, texture. Suitable for the excess power. toilet ssues and cheap produc on of rayon, Suitable for prin ng-wri ng and paper books where cellulose deriva ves and newsprint papers. strength and ease of high strength paper. bleaching.
Balasubramanian S 16 Pulp and Paper – Pulping Methods Difference between sulfate (kra ) and sulfite process
Characteris cs Sulfate, or Kra pulp(Alkaline) Sulfite Pulp (Acid) 1. Cellulosic or fibrous raw Any kind of wood, so or hard Coniferous; must be good color material and free from phenolic compounds
2. Cooking liquor or white 60% NaOH Composi on depends on process
liquor composi on 25% Na2S modifica ons, but all use SO3 15% Na2CO3 (a)Magnifite process: Mg(HSO3)2 + free SO2 in acid media
(b)Neutral Sulfite process:
Na2SO3, Na2CO3, NaHCO3
(c)Acid Sulfite process:
NaHCO3, Na2CO3
Balasubramanian S 17 Pulp and Paper – Pulping Methods
Characteris cs Sulfate, or Kra pulp(Alkaline) Sulfite Pulp (Acid) 3. Cooking condi ons Time 2 – 5 h, temp 170 – 176 Time 6 – 12 h, temp 125 – deg. C, Pressure 660 – 925 kPa 160 deg, C, Pressure 620 – 755 kPa
4. Chemical recovery Most of the process is devoted SO3 Relief gas recovered; to the recovery of cooking magnesium liquor recovered chemicals, with recovery of and reused a er wood heat through organic ma er diges on and pulp washing dissolved in liquor from wood; Chemical losses from the system is replenished with salt
cake and Na2SO4
5. Material of construc on Digesters, pipelines, pumps, Acid and magnifite process and tanks can be made of mild requires digester lining of steel or, preferably of stainless acid-proof brick; fi ngs of steel chrome-nickel steel, lead and bronze
Balasubramanian S 18 Pulp and Paper – Pulping Methods
Characteris cs Sulfate, or Kra pulp(Alkaline) Sulfite Pulp (Acid) 6. Pulp characteris cs Brown color; difficult to bleach; Dull white color; easily strong fibers; resistant to bleached; fibers weaker than mechanical refining Kra 7. Typical paper products Strong brown bag and White grades: book paper, wrapping, mul wall bags, bread wrap, fruit ssue, gumming paper, strong white sanitary ssue wri ng and prin ng paper, corrugated boards and cartons
Balasubramanian S 19 Pulp and Paper – Manufacture
General process
Wood – Cellulose fiber White liquor Bleaching Chemicals Process Paper Addi ves or Sizing agents
Water and Steam
Balasubramanian S 20 Pulp and Paper – General aspects process steps
Wood Wood is debarked and made into chips
Pulping 1. Disintegra on of cellulose fibers 2. Removal of lignin
Washing and Improves the brightness of pulp Bleaching
Stock Chemicals as addi ves were added to 1. Increase flexibility, opacity, so ness and weight of finished paper Prepara on 2. Sizing is carried out to reduce water or other liquid penetra on
Forma on of paper by Paper machine 1. Forming a wet web followed by pressing the wet sheet 2. Drying the sheet
Paper Products Finished paper products
Balasubramanian S 21 Pulp manufacture – Block diagram for Kraft process Cooking liqour and steam Wood Blow down Chips Chip Bin Digester Strainer tank Black liquor
Black Liquor Black liquor Soda recovery tank Bleaching agents
Pulp to Rotary Bleaching Screen bleaching drum Addi ves Black liquor Knots and undigested residue Stock Refiner or Wire /Web Head box Prepara on Beater forming
Drying Finishing Rewinder Press rolls Cylinders Balasubramanian S 22 Pulp manufacture – Process diagram for Kraft process
Balasubramanian S 23 Pulp and Paper
Defini ons History of Pulp and Paper Global Pulp and Paper industries scenario Indian Pulp and Paper Industries scenario Raw materials Manufacture of Pulp and paper Process descrip on Paper products
Balasubramanian S 24 Pulp manufacture – Process description
Balasubramanian S 25 Pulp manufacture-Soda recovery for the Kraft process
Balasubramanian S 26 Pulp manufacture – Process description of soda recovery
Balasubramanian S 27 Pulp manufacture – Process description of soda recovery
Balasubramanian S 28 Paper Machine
Primary process involved in the paper sheet forma on:
• Random arrangement of fibers into a wet web • Removal of free water from wet web by wet pressing • Progressive removal of addi onal water by heated rolls
Balasubramanian S 29 Paper Machine
Balasubramanian S 30 Pulp and Paper
Defini ons History of Pulp and Paper Global Pulp and Paper industries scenario Indian Pulp and Paper Industries scenario Raw materials Manufacture of Pulp and paper Process descrip on Paper products
Balasubramanian S 31 Pulp manufacture – Process description of soda recovery
Balasubramanian S 32 Paper Products
Paper Wri ng-prin ng papers News print papers Coated prin ng papers Packaging papers Tissue papers Corrugated boards
Balasubramanian S 33 References
1. Dryden C. E, Outlines of Chemical technoloy – for the 21st Century, 3rd edi on, East-West Press (2004)
2. Aus n G. T, Shreve’s Chemical Process Industries, 5th edi on, Mc Graw Hill Interna onal edi ons (1984)
3. Finar IL, Organic Chemistry Vol. 1 6th Edi on Pearson Educa on 2009 pp.116-117
17/02/11 Balasubramanian S 34