Projects For :-
As desired by the Cess Committee the
outcome of the following completed Cess Funded Projects will be presented in
workshop proposed to be held in May 2011, at New Delhi
||Name of projects
||Name of Sponsoring Agency
||Data for Amendments in Stiffness
Specification for different Paper grads in BIS standards
||Colour & TDS Removal from ECF Bleach
Plant Effluent (IPMA)
||Secondary Sludge Treatment & Disposal
in Pulp and Paper Industries
||Online batch digester monitoring and
control of Kappa number in Indian Pulp & Paper Mills
||CPPRI / IIT
Cess Project on "Data
for Amendment in stiffness specifications for different Paper Grades under
Stiffness has become an important
parameter for most of paper grades. Bending stiffness is necessary for good
runnability on the printing presses and converting machines. A uniform
tensile stiffness over the width of the paper web is for instance a
condition for good register. During post-treatment in the bindery, the
folding machines usually require a certain bending stiffness for good
convertibility. In photo copying machine proper stiffness is necessary for
proper functioning. Paper products like corrugated fibre board boxes are
manufactured from materials which have a marked stiffness towards tensile
and compression forces. Modern liquid packages, cartons etc. are further
examples of a paper usage which would be impossible without the considerable
bending stiffness of the material. Overall stiffness has become an important
parameter for most of paper grades.
Bureau of Indian Standards has
prescribed different values for cover paper, photocopier paper, coated board
and straw board. Different terminology has been used in different standards
and there is no uniformity in prescribed methods of testing and ways of
expressing the results. Stiffness measurement has become a confused concept
according to the procedure prescribed in different BIS standards. The
nomenclature used in these standards is not as per International Standards.
The test method prescribed is no longer relevant. There is no uniformity in
specified values. This is posing lot of problem to Paper manufacturers and
traders dealing in national and international market. Detailed studies were
carried out on different papers viz. cover paper, coated board, straw board
and photocopier papers using L & W stiffness tester (bending stiffness
type) and Taber tester. Based on the results of above study following values
are recommended for adoption in different BIS standard.
||Recommended Bending stiffness index
valueAvg MD & CD
For photocopier paper which is
normally in grammage range of 70 to 80 g/m2, instead of specifying Bending
stiffness index, the stiffness in Taber unit or millinewton should be
||Recommended stiffness Avg MD & CD
||Taber unit - 2.5
|mN - 5.0
Color and TDS removal from bleach
||DC (Paper), DoIPP, Govt of India
||Tamilnadu Newsprint and Papers Ltd.
||CLRI laboratory of CSIR
|Total Budget (Rs. Lacs)
effluent generated in Pulp & Paper industry is treated to reduce the
COD, TDS and other parameters to conform to the pollution control board
norms. Many mills in India have started opting for pollution minimisation at
source and switched over to environment friendly process technologies such
as Oxygen-De-Lignification (ODL) and Elemental chlorine free (ECF) bleaching
to reduce pollution load instead of end-of-pipe treatment, which is not
sustainable both environmentally and economically.
colour, COD and inorganic TDS are a major source of pollution, which are
generated even in the modern bleaching process however to significantly
lesser level as the lignin entering the bleaching section is reduced by 40
-50% by ODL to about 1.5% of residual lignin and subsequently the Elemental
Chlorine addition is reduced by 2.6 times by replacing elemental chlorine
with Chlorine-dioxide having higher oxidation potential.
Pilot Plant was commissioned on 12.7.2009.
2. The trials with Eop
effluent shows that colour and COD reduction to the level of 80 to 85 % in
the first ten days. The rate of COD reduction was 0.68 mg of COD / gm of
activated carbon in the FACCO reactor of CLRI design.
3. Due to the
high sodium content (1200 ppm) and viscous nature of the effluent caused
saturation of the catalyst in FACCO process, the reduction has decreased in
the subsequent trials to 40 to 50 %; COD reduction -36 mg/gm of carbon.
Ferrate dosage was increased to 100 ppm and the COD reduction improved to
5. When the flow rate was optimised at 600 to 800 lit/hr and
Fenton added to EOP filtrate there was an improvement in the reduction of
color & COD to 60 %.
6. Pre-treated Eop filtrate with FACCO
process is processed through UF/RO/Nano membrane system helped in
segregation of Calcium and Sodium as envisaged and recovery of good quality
RO water. However, TNPL has opted for recycling the extraction filtrate
through ODL stage and currently discharging the acid bleach filtrate.
Acid filtrate of bleach plant was treated with lime soda process to
neutralise the effluent, which also reduced the COD and hardness along with
colloidal silica. This process generates lime sludge that can go into lime
cycle. The filtrate primarily contains sulphate, chloride and COD. The COD
is further reduced using anaerobic and aerobic process. This biologically
treated filtrate is passed through NF system to separate the chlorides and
sulphates. The NF concentrate primarily contains sulphate with minor
contaminants such as chlorides which can partially substitute saltcake
requirement in SRP line.
8. Based on these concepts TNPL is trying
to validate the process to close the bleach loop.
On-line Digester Monitoring and
Control of Kappa Number in Indian Pulp & Paper Mills
Growing demands for improved quality, increasing global
competition and stringent environmental and safety regulations have
emphasized the need for chemical industries to rely on model based
technologies for optimization and control. Model Predictive Control (MPC)
has emerged as one of the powerful control algorithms which predicts future
output behavior from dynamic model and on-line measurements of the plant.
The work under this CESS funded project focuses on the development of a
mathematical model of Pandia Digester and online kappa measurement system
based on this model which will work on the feed back of soft sensors (pH,
conductivity and temperature) from the Pandia digester. Pandia digester is a
horizontal continuous digester used in pulp and paper industry for the
cooking of non-wood fibers. A kinetic model for delignification of wheat
straw has been adopted from literature and it was also further validated by
laboratory studies at Central Pulp and Paper Research Institute (CPPRI).
Since this model was not complete for incorporation in the system,
we have augmented it by using data corresponding to wood and modified it in
order to predict exit Kappa number based on experimental data provided by
CPPRI, Saharanpur. With suitable assumptions, a dynamic model has been
derived based on first principles and is simulated in MAT LAB(R).
state profiles have been obtained and parametric sensitivity analysis has
been performed on the model. As the model for continuous digester is
non-linear, Extended Kalman Filter technique has been used for state
estimation. Input disturbance modeling has been done to account for steady
state sets observed due to parameter mismatches.
of the model, design data of the digester was collected from one wheat straw
based mill alongwith the operational parameters. It was then validated by
running the program with the input values of the mill data and the outputs
were compared with the operational values from the mills. Necessary
correction factors were used to match the program out put with the mill
results. The results have shown that the kappa variation pattern can be
observed with the feed back from the mill. The system developed in the study
has capabilities to accept the online temperature, pH and conductivity of
the black liquor from the digester at different points and predict the
online kappa number, alkali profile at different points along the digester
tube length. The system for the insertion of the probes at appropriate
position is required to be designed by the supplier to effectively monitor
the online kappa with the developed software.
For Further Details Regarding Projects
Please Contact :
Dr. R. M. Mathur,
Central Pulp and Paper Research Institute,
: firstname.lastname@example.org, email@example.com
10. Birbal Road, New Delhi - 110014 (India)
(011) - 24315400
Fax : (011) - 2431 5401
Email : firstname.lastname@example.org
Person: Dr. Kawaljeet Singh (Sc E I & officer In charge)
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