PPT - Sulfate (Kraft) Pulping Process Chemical Engineering Notes | EduRev

Chemical Technology

Chemical Engineering : PPT - Sulfate (Kraft) Pulping Process Chemical Engineering Notes | EduRev

 Page 1


WHAT IS PULP?
Pulp is a commercial fibrous material obtained from
bamboo, wood, bagasse (waste material) etc. by
mechanical and chemical means.
 Pulping means disintegration of bulky fibrous material
to small fibers.
 There are mainly three modes of production of pulp:
 Mechanical
 Chemical
 Semi chemical
Page 2


WHAT IS PULP?
Pulp is a commercial fibrous material obtained from
bamboo, wood, bagasse (waste material) etc. by
mechanical and chemical means.
 Pulping means disintegration of bulky fibrous material
to small fibers.
 There are mainly three modes of production of pulp:
 Mechanical
 Chemical
 Semi chemical
CHEMICAL CONVERT WOOD BLOCKS INTO
CELLULOSIC PULP
WOOD BLOCKS
CELLULOSIC PULP
Page 3


WHAT IS PULP?
Pulp is a commercial fibrous material obtained from
bamboo, wood, bagasse (waste material) etc. by
mechanical and chemical means.
 Pulping means disintegration of bulky fibrous material
to small fibers.
 There are mainly three modes of production of pulp:
 Mechanical
 Chemical
 Semi chemical
CHEMICAL CONVERT WOOD BLOCKS INTO
CELLULOSIC PULP
WOOD BLOCKS
CELLULOSIC PULP
SULFATE (KRAFT) PULPING PROCESS
 Most popularly used process.
 This is an alkaline process.
 Na2SO4 is added to the cooking liquor, So it’s
common name is sulfate process.
 The presence of sodium sulfide makes bleaching of
pulp easier and the paper produced has better
strength.
Page 4


WHAT IS PULP?
Pulp is a commercial fibrous material obtained from
bamboo, wood, bagasse (waste material) etc. by
mechanical and chemical means.
 Pulping means disintegration of bulky fibrous material
to small fibers.
 There are mainly three modes of production of pulp:
 Mechanical
 Chemical
 Semi chemical
CHEMICAL CONVERT WOOD BLOCKS INTO
CELLULOSIC PULP
WOOD BLOCKS
CELLULOSIC PULP
SULFATE (KRAFT) PULPING PROCESS
 Most popularly used process.
 This is an alkaline process.
 Na2SO4 is added to the cooking liquor, So it’s
common name is sulfate process.
 The presence of sodium sulfide makes bleaching of
pulp easier and the paper produced has better
strength.
CHEMICAL REACTIONS
(i) Digestion (hydrolysis and solubilization of lignin):
R-R’ + NaOH ? R”COONa + ROH
R-R’ + Na2S ? Mercaptans
(ii) Chemical recovery from black liquor:
(a) Smelting:-
2NaR + air ? Na2CO3 + CO2
(lignin)
Na2SO4 + 2C  ? Na2S + 2CO2
(from R)             (white liquor)
Page 5


WHAT IS PULP?
Pulp is a commercial fibrous material obtained from
bamboo, wood, bagasse (waste material) etc. by
mechanical and chemical means.
 Pulping means disintegration of bulky fibrous material
to small fibers.
 There are mainly three modes of production of pulp:
 Mechanical
 Chemical
 Semi chemical
CHEMICAL CONVERT WOOD BLOCKS INTO
CELLULOSIC PULP
WOOD BLOCKS
CELLULOSIC PULP
SULFATE (KRAFT) PULPING PROCESS
 Most popularly used process.
 This is an alkaline process.
 Na2SO4 is added to the cooking liquor, So it’s
common name is sulfate process.
 The presence of sodium sulfide makes bleaching of
pulp easier and the paper produced has better
strength.
CHEMICAL REACTIONS
(i) Digestion (hydrolysis and solubilization of lignin):
R-R’ + NaOH ? R”COONa + ROH
R-R’ + Na2S ? Mercaptans
(ii) Chemical recovery from black liquor:
(a) Smelting:-
2NaR + air ? Na2CO3 + CO2
(lignin)
Na2SO4 + 2C  ? Na2S + 2CO2
(from R)             (white liquor)
CONTINUE….
(b) Causticzing:-
Na2CO3 (aq) + Ca(OH)2 (s) ? 2NaOH (aq) + CaCO3 (s)
(green liquor)                         (white liquor)
CaCO3 ? CaO + CO2
CaO + H2O ? Ca(OH)2
Read More
Offer running on EduRev: Apply code STAYHOME200 to get INR 200 off on our premium plan EduRev Infinity!

Related Searches

shortcuts and tricks

,

Important questions

,

Viva Questions

,

Objective type Questions

,

Sample Paper

,

study material

,

PPT - Sulfate (Kraft) Pulping Process Chemical Engineering Notes | EduRev

,

pdf

,

mock tests for examination

,

video lectures

,

Semester Notes

,

Summary

,

past year papers

,

MCQs

,

ppt

,

Previous Year Questions with Solutions

,

Extra Questions

,

Exam

,

practice quizzes

,

PPT - Sulfate (Kraft) Pulping Process Chemical Engineering Notes | EduRev

,

PPT - Sulfate (Kraft) Pulping Process Chemical Engineering Notes | EduRev

,

Free

;