TY  - JOUR
TT  - Evaporation Plant for Recycling of Caustic Soda
AU  - Elmas, Emin Taner
PY  - 2017
DA  - September
Y2  - 2017
DO  - 10.19072/ijet.331578
JF  - International Journal of Engineering Technologies IJET
JO  - IJET
PB  - İstanbul Gelisim University
WT  - DergiPark
SN  - 2149-0104
SP  - 176
EP  - 185
VL  - 3
IS  - 3
KW  - Evaporation
KW  - Recycling
KW  - Caustic soda
KW  - Sodium hydroxide
KW  - Vacuum
KW  - Steam
N2  - The most important problem that humanityis expected to face in the coming century shall be environmental pollution. Onone hand, the population of human beingsare using natural resources rapidly, on the other hand, they are addinghundreds of pollutants in the form of metals, acids, bases and etc. Thus, theyhave created an abnormal situation whichhas resulted in an imbalance in the natural systems.  As the industrialization improves, itcreates pollution and also it creates jobs for the people. Especially indeveloped countries, for instance European countries and U.S.A. there are alsomany stringent restrictions for the environmental pollution, and there are manylaws, political arrangements. Of course , a pollution free environment willrequire a high cost, often an expensive operation. However , it is much morecostlier trying to undo the damage done. On the basis of concept tried to mentionabove human beings have studied on the subjects related with environmentalpollution. They have established waste water treatment plants, many kinds ofrecycling and recovery plants, and etc. In this study , it has been tried toestablish such an idea that a pollution free environment may be available ifthis technical process is used properly. So, the first goal of this study is toprovide a concise statement of the requirements and opportunities for obtainingenvironmental benefits. The second objective will be to provideeconomical savings while providing the environmental benefits at the same time. To emphasize the great importance of abovementioned subjects the application of recycle technology for the sodiumhydroxide (NaOH), which is named as caustic soda in industrial processes,realized by means of an evaporation plant is used. Caustic soda is used in textile industryfor mercerizing process as it is used in many different processes. To give thecotton more strength and to obtain a smoother surface and an improved affinitythe mercerizing is essential. After being finished the mercerizing operation,generally the process solution (containing caustic soda) is discharged to theenvironment,. e.g. , rivers, seas and sewage. In spite of the fact that this applicationis widely spread in use, it is forbidden in all developed countries todischarge the caustic soda solutions even at a 1% concentration since thecaustic soda is highly basic (highly alkaline). For this reason it is veryharmful for the environment. It is possible to extract the caustic sodafrom the caustic soda solutions before discharging it to the environment forpreventing the harms of this material. The washing water containing NaOH will beconcentrated by H2O evaporation and shall be recycled in themercerizing system. The concentration may take place in a single or multiple –stage (double–stage) installation under vacuum or atmospheric pressure. The washing water to be concentrated ismoved from the storage tank to the first evaporation stage and the thermalenergy for evaporation operation is added by the steam. The vapor coming from the first evaporation stage isused for the next evaporation stage as the heating steam of this unit. Thevapor from the last stage is condensed in a condenser. The condensed vapor canbe safely discharged and the concentrated caustic soda can be reused for thesubsequent mercerizing operation. So, both economical profits and environmentalbenefits can be provided by reusing the caustic soda for next processes , afterit is recovered by the help of this way. Desalination unit in Jeddah which is thecapital city of Saudi Arabia , is an example for this kind of operations.. Thisplant was established 1970’s and has been used as both a power station and adesalination unit. At this plant the exhaust steam coming from the steamturbines is used as the heating steam for evaporators of desalination unit. Unfortunately, in our country, even inİzmir, the waste water of textile industry is discharged to the environment.Because , the environmental laws are not adequate and theenterprisers think that a recycling plant is not an economical investment.However , it is stated in this study that such a concept is not right. It has been tried to show that such an investment, i.e.,“An Evaporation Plant for Recycling of Caustic Soda” may be profitable if it isinstalled and operated properly, and also it has been tried to increase the attractivity of thesekinds of plants . It is hoped that, the laws and stringentrestrictions related with environment shall be arranged, so that we shall live in a healthy world.
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UR  - https://doi.org/10.19072/ijet.331578
L1  - https://dergipark.org.tr/en/download/article-file/359900
ER  -