PRODUCTION OF CAUSTIC SODA
“Chemical Engineering
Department
Graduation Project”
Çağla YARMACI, Emine YETİM,
Prof. Dr. Ayşe Nilgün AKIN
Kocaeli University, Chemical Engineering Department, Kocaeli, 41380, Turkey
3. CAUSTIC PRODUCTION IN KORUMA
CHLOR ALKALI PLANT
ABSTRACT
The chlor-alkali industry is one of the most energy intensive electrochemical
processes in the world. Caustic soda is a product of alkali industry which is produced
by the way of electrolyse of salty water. The industry of chlor alkali is an
electrochemical process which consumes the most energy in the world. Thats why
these processes which have a high energy productivity are important. Caustic soda is
one of the most important raw material of chemical industry. The demand of caustic
was 73 millions ton around the World in 2011. Caustic soda which has a large usage
area is also used alcaline battery. Institutionally the process within mercury cell is
used in the product of caustic but this method gives place to the process within
diaphragm cell and today the membrane technology is dominant. The membrane
technology which changes ion and has the biggest energy conversation, perfect
product quality, not contaminant is a modern chlorine alkali. With this performance,
the information about the industry of chlorine alkali; especially about caustic soda is
given and the steps of production process is investigated. The membrane technology
is concentrated. Lime soda process, trona process and electrolytic cell process are
used in the produtivity in caustic. Membrane cell process is the best of all cell
processes that are mentioned.
Keywords: Caustic Soda, Chlor Alkali, NaOH, Elektrolyse, Membrane Cell
General view;
Electrolysis;
1. INTRODUCTION
Caustic soda is a product of chlorine alkali industry. The main production method is the
electrolysis of salty water. The process can be carried out in these three cell types: mercuric,
diaphragm and membrane cells. The process of mercuric and diaphragm cells was developed
in late 1800’s and the process of membrane cells was developed in 1970’s. By electrolysis of
salty water, chlorine gas is produced in the positive pole and hydrogen and caustic soda are
produced in the negative pole.
Chlorine alkali industry is one of the most energy-consuming electrochemical processes.
So developments about energy conservation are required. The least energy-consuming cell
type in caustic soda production is membrane cell. Studies on membrane cell still continue.
Energy conservation can be increased with the improvements on new membranes.
In this work caustic soda production methods are investigated. Although mercuric cells
provide high concentration (50%) of caustic soda production, they lose their significance
because of high energy-consuming and including mercury. Diaphragm cells enable low
concentration and low purity of caustic soda production. The most appropriate method can be
shown as membrane cell process because of high purity caustic soda production and low
energy-consuming.
2. CAUSTIC SODA
5%
2% 1% 1%
4%
4%
5%
31%
5%
12%
16%
14%
Fıgure 2.1:Uses of Caustic Soda [1]
Organics
Types of Caustic Soda;
Others
Paper cellulose
Other inorganics
Aluminum and metals
Food industries
Water treatment
soop
Bleaching
Mineral oil
Artificial silk
Sud Caustic Flake Caustic Prill Caustic
Phospates
Figure 3.1: Process of caustic production
Table 3.1:Product quality control report of flake caustic
Flake Caustic
Product Date
Parametre
Unit
Spec
18.05.2015
Appearange
-
White flake
White flake
NaOH
%
Min. 98
98,66
Na2CO3
%
Max. 0,40
0,54
NaCl
%
Max. 0,1
0,014
Fe
ppm
Max. 15
5,65
CONCLUSION
Figure 3.2: Caustic production process flow sheme [3]
REFERENCES
1. Brinkmann, T., Santonja, G.G., Schorcht, F., Roudier, S., Sancho, L.D., Best Available
Techniques (BAT) Reference Document for the Production of Chlor-alkali, JRC Science
and Policy Reports, Luxemburg, Publications Office of the European Union, 2014.
2. O’Brien, T., F., Bommaraju, T., V., Hine, F., Chlor Alkai Technology Volume 1: Fundementals,
New York, Springer, 2005
3. Koruma Chlor-alkali Company
The chlor-alkali industry is developed and geographically dispersed in various time
zones. It is a problem that sodium hydroxide and chlorine produced together and almost
same amount. These two products have very different courses and different end-use
market Dynamics and demand’s of them almost never overlap.
Sodium hydroxide is usually marketed as a 50% aqueous solution, it can be maintained for
a long time and can be easily transported.
Mainly, caustic soda production method investigated in this report. Clearly the
conclusions reached is that the most appropriate method is membrane cell electrolysis.
Membrane cell process is advantageous than olders others because not mercury or
asbestos not used and has lower energy consumption. Despite these advantageous,
transition to membrane cell prosess is slowly in Europe. Because plants that established
1970’s have 40-60 years service life and there is no need increase capacity. There is no
legislation that will accelerate this transition is not available. Nearly 56% of the World used
membrane process.
Three manufacturers that in our country today as the company realizes its production
with membrane cell process.
Graduation Project
Baki Komsuoglu Culture and Conference Center
5th June 2015, KOCAELI