Title of Invention

A METHOD FOR SELECTION OF ECONOMIC GRADE OF STEEL IN SUGAR INDUSTRY TO AVOID CORROSION AND OPERATIONAL BREAK DOWN

Abstract The present invention relates to a method for selection of economical grade of steel pipe in sugar industry by analyzing various different grades of steel pipes (A,B,C,D,E,F) to get a comparative assessment of their performance in relation to corrosion resistance in sugar cane juice by electrochemical Tafel extrapolation technique the method comprising the steps of collecting of different grades of steel pipes (A,B,C,D,E,F) and generating of corrosion rate data by experiment of all the grades by carrying out Tafel polarization experimentations and plotting corrosion rates data obtained by extrapolarisation in a graph having zero current potential in x-axis and potential level of different grade for initiation of corrosion in y-axis and selecting the economical steel pipe which have less susceptible to corrosion (2nd maximum among all the metals as 1st maximum is costly one).
Full Text FIELD OF THE INVENTION
The present invention relates a method of selection of steel grade for pipe
of Sugar Industry. More particularly, the present invention relates to a
method for selection of economic grade of steel pipe adaptable in sugar
industry to avoid unwanted operational breakdowns caused by corrosion.
BACKGROUND OF THE INVENTION
In India, the sugar Industries are operated in a span of about 6 to 8
months in a year and any sudden occurance of operational failure during
this small span causes severe loss in the productivity of sugar products. It
is identified that one of the main causes of operational failure takes place in
sugar Industries is the leakage occurance of steel pipe due to corrosion.
The existing steel pipe is made of IS: 10748 grade I as per Indian standard
IS: 1239 having a chemical composition 0.04%C and 0.2-0.3% Mn in
various thickness ranging from 3 to 6mm.

OBJECTS OF THE PRESENT
It Is therefore, an object of the present invention to propose a method for
selection of economical grade of steel pipe adaptable In sugar industry
which eliminates the adversity of prior art.
Another object of the present invention Is to propose a method for selection
of economical grade of steel pipe adaptable in sugar industry which Is
hygienic for carrying sugar cause juice in sugar Industry.
A further object is to propose a method for selection of economical grade of
steel pipe adaptable in sugar industry which avoids unwanted operational
breakdown caused by corrosion
A still further object is to propose a method for selection of economical
grade of steel pipe adaptable in sugar industry which increases the
productivity of sugar cause juice
An yet further object is to propose a method for selection of economical
grade of steel pipe adaptable in sugar industry which is cost effective.

SUMMARY OF THE INVENTION
To simulate actual service condition, accelerated corrosion studies were carried
out over various grades of steel pipes at ambient temperature in pure fresh
sugar cane juice. The methodology consists of analyzing various different grades
of steel pipe for corrosion resistance in sugar cane juice. The grades of steel
studied and their sample conditions are describes below:


All the above mentioned grades were analysed to get a comparative
assessment of their performance is sugar cane juice. The Tafel
extrapolation technique was used to obtain the result of the experiment.
The pH value of the sugar cane juice was measured before and after each
set of experiment. The change in pH value before and after each set of
experiment was not significant which ensured the freshness (almost no
fermentation) of the sugar cane juice
RESULT
The samples were analysed for accelerated corrosion test by electro
chemical method. In order to judge material performance in actual
corrosion atmosphere, the tests were carried out in fresh sugar cane juice
at ambient temperature. Tafel polarization experimentations were carried
out for calculating corrosion rates of all grades. To determine the corrosion
rate from Tafel plot, cathodic and anodic polarization is extrapolated to
corrosion potential. The point of intersection of extrapolated lines
corresponds to current density for metal dissolution ie, corrosion rate.
The comparative Tafel plots of all the grade studied have been shown in
figure- 1. The zero current potential with respect to reference electrode for
different grades are listed in Table - 1 in decreasing order. The corrosion

rates obtained by extrapolations have been tabulated in Table 2 in
increasing order.
Table 1: Zero Current Potential with respect to reference electrode for
different grades (in decreasing order).


Table 2: Corrosion rate of various grades I sugar cane juice (in increasing
order).

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Figure-1- Shows the Tafei plot of various grades in sugar cane juice
indicating comparative potential level of different grade for initiation of
corrosion.

INVENTION
Figure-1- Shows the corrosion rate of various grade In sugar cane Juice.
The figures shows log current density (A/cm2) along the x-axis and
potential (v) vs Eref in y-axis. Tafel plot of various grades in sugar cane
Juice indicating comparative potential level of different grade for initiation
corrosion.
From figure-1, the Tafel plot Indicates that the stainless steel (F) is the
most passive (-230.7) with respect to initiation of corrosion followed by cu-
fi/ bearing grade (C) shown in Table 1
/
As far as material dissolution rate in sugar cone juice is concerned, the
lowest rate is indicated by stain less steel followed by corten and cu-
bearing steel increasing order (Table-2)
As shown in Table, 2 and based on combination of stainless steel (F) cu
bearing steel (C) and corten steel (B) cu-bearing grade steel (C) appears to
be the most economical grade to replace existing grade (IS: 10478 and
grade-1) the expected service life with cu-bearing grade (C) is expected to
be 25% more compared to existing grade. The higher corrosion rate of GI

(D) corresponds to higher dissolution rate of zinc and possibility of
contamination of sugar cane juice.

WE CLAIM
1. A method for selection of economical grade of steel pipe in sugar industry
analyze on various different grades of steel pipes (A,B,C,D,E,F) to get a
comparative assessment of their performance in relation to corrosion
resistance in sugar cane juice by electrochemical Tafel Extrapolation
technique the method comprising the steps of:
- collecting of different grades of steel pipes (A,BfCfDfE,F);
- generating of corrosion rate data by experiment of all the grades by
carrying out Tafel polarization experimentations;
- plotting corrosion rates data obtained by extrapolarisation in a graph
having zero current potential in x-axis and potential level of different
grade for inflation of corrosion in y-axis;
- selecting the economical steel pipe which have less susceptible to
corrosion (2nd maximum among all the metals as 1st maximum is costly
one);
characterised in that the said economical grade steel pipe in sugar
industry minimizes the maintenance cost due to replacement and repair of
equipments due to corrosion abrasion.
2. The method as claimed in claim 1, wherein a comparative assessment of
performance of different grades of steel pipe was carried out in which the
pH value of the sugar cane juice was measured before and after each set
of equipment.

3. The method as claimed in claim 1, wherein Tafel polarization experiments
were carried out for calculating corrosion rate of all grades from Tafel
plot, cathoidic and anodic polarization is extrapolated to corrosion
potential by the point of inter section line corresponds to current density
for metal dissolution i.e. corrosion rate.
4. A method for selection of suitable and economical grade of steel pipe in
sugar industry as substantially described and illustrated herein with
reference to accompanying drawings.


The present invention relates to a method for selection of economical grade of
steel pipe in sugar industry by analyzing various different grades of steel pipes
(A,B,C,D,E,F) to get a comparative assessment of their performance in relation to
corrosion resistance in sugar cane juice by electrochemical Tafel extrapolation
technique the method comprising the steps of collecting of different grades of
steel pipes (A,B,C,D,E,F) and generating of corrosion rate data by experiment of
all the grades by carrying out Tafel polarization experimentations and plotting
corrosion rates data obtained by extrapolarisation in a graph having zero current
potential in x-axis and potential level of different grade for initiation of corrosion
in y-axis and selecting the economical steel pipe which have less susceptible to
corrosion (2nd maximum among all the metals as 1st maximum is costly one).

Documents:

01095-kol-2006-correspondence-1.1.pdf

01095-kol-2006-form-9.pdf

01095-kol-2006-g.p.a.pdf

01095-kol-2006.abstract.pdf

01095-kol-2006.claims.pdf

01095-kol-2006.correspondence others.pdf

01095-kol-2006.description(complete).pdf

01095-kol-2006.drawings.pdf

01095-kol-2006.form-1.pdf

01095-kol-2006.form-2.pdf

01095-kol-2006.form-3.pdf

1095-kol-2006-correspondence.pdf

1095-kol-2006-examination report.pdf

1095-kol-2006-form 18.pdf

1095-kol-2006-form 3.pdf

1095-kol-2006-form 9.pdf

1095-kol-2006-gpa.pdf

1095-kol-2006-granted-abstract.pdf

1095-kol-2006-granted-claims.pdf

1095-kol-2006-granted-description (complete).pdf

1095-kol-2006-granted-drawings.pdf

1095-kol-2006-granted-form 1.pdf

1095-kol-2006-granted-form 2.pdf

1095-kol-2006-granted-specification.pdf

1095-kol-2006-others.pdf

1095-kol-2006-petition under rule 137.pdf

1095-kol-2006-reply to examination report-1.1.pdf

1095-kol-2006-reply to examination report.pdf


Patent Number 247588
Indian Patent Application Number 1095/KOL/2006
PG Journal Number 17/2011
Publication Date 29-Apr-2011
Grant Date 26-Apr-2011
Date of Filing 18-Oct-2006
Name of Patentee TATA STEEL LIMITED
Applicant Address RESEARCH AND DEVELOPMENT AND SCIENTIFIC SERVICES DIVISION, JAMSHEDPUR
Inventors:
# Inventor's Name Inventor's Address
1 RAJIV MISHRA TATA STEEL LIMITED RESEARCH AND DEVELOPMENT AND SCIENTIFIC SERVICES DIVISION, JAMSHEDPUR 831 001
2 NITU RANI TATA STEEL LIMITED RESEARCH AND DEVELOPMENT AND SCIENTIFIC SERVICES DIVISION, JAMSHEDPUR 831 001
3 C.B.LUNAWAT TATA STEEL LIMITED RESEARCH AND DEVELOPMENT AND SCIENTIFIC SERVICES DIVISION, JAMSHEDPUR 831 001
4 NIKHILES BANDYOPADHYAY TATA STEEL LIMITED RESEARCH AND DEVELOPMENT AND SCIENTIFIC SERVICES DIVISION, JAMSHEDPUR 831 001
5 TAPAN KUMAR ROUT TATA STEEL LIMITED RESEARCH AND DEVELOPMENT AND SCIENTIFIC SERVICES DIVISION, JAMSHEDPUR 831 001
PCT International Classification Number C21D 8/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA