CHEMICAL PROCESS INDUSTRIES-1 (2130505) SEM -3 YEAR 2015-16 BATCH 1C05 POWER POINT PRESENTATION BY: ENROLLMENT NO NAME 1) 140110105056 MILIN SHAH 2) 140110105057 PARTH SHAH 3) 140110105058 RAJ SHAH 4) 140110105059 SHREERAJ JETHWA

CHLOR ALKALI INDUSTRIES

1.INTRODUCTION THE CHLOR ALKALI PROCESS IS AN INDUSTRIAL PROCESS FOR THE ELECTROLYSIS OF NaCl. IT IS THE TECHNOLOGY USED TO PRODUCE CHLORINE AND SODIUM HYDROXIDE (CAUSTIC SODA). 35 MILLION TONS OF CHLORINE WERE PREPARED BY THIS PROCESS IN 1987.

USUALLY THE PROCESS IS CONDUCTED ON A BRINE(AQUEOUS SOLUTION OF NaCl ),in WHICH NaOH, HYDROGEN AND CHLORINE RESULT. RELATED PROCESSES ARE KNOWN THAT USE OF MOLTEN NaCl TO GIVE CHLORINE AND SODIUM METAL OR CONDENSED HYDROGEN CHLORIDE TO GIVE HYDROGEN AND CHLORINE.

2. PRODUCTION METHODS CHLOR ALKALI PROCESS MAINLY USES THREE METHODS.THEY ARE A) BY ELECTROLYSIS 1)MEMBRANE CELL 2)DIAPHRAGM CELL 3) MERCURY CELL B) BY OXIDATION OF CHLORINE. C) BY LIME SODA PROCESS.

A) MEMBRANE CELL

MEMBRANE CELL USED IN ELECTROLYSIS OF BRINE. AT ANODE, CHLORIDE IS OXIDIZED TO CHLORINE. THE ION SELECTIVE MEMBRANE B ALLOWS THE COUNTERION Na⁺ TO FREELY FLOWS. AT THE CATHODE, WATER IS REDUCED TO HYDROXIDE AND HYDROGEN GAS. AS A RESULT PRODUCTS LIKE SODIUM HYDROXIDE AND CHLORINE GAS IS OBTAINED.

B) DIAPHRAGM CELL IN THE DIAPHRAGM CELL PROCESS THERE ARE TWO COMPARTMENTS SEPERATED BY A PERMEABLE DIAPHRAGM,OFTEN MADE OF ASBESTOS FIBRES. BRINE IS INTRODUCED INTO THE ANODE COMPARTMENT AND FLOWS INTO THE CATHODE COMPARTMENT AND SAME REACTION OCCURS AS IN CASE OF MEMBRANE CELL.

C) MERCURY CELL

IT IS ALSO KNOWN AS CASTNER KELLNER PROCESS IT IS ALSO KNOWN AS CASTNER KELLNER PROCESS.A SATURATED BRINE SOLUTION FLOATS ON TOP OF THE CATHODE WHICH IS A THIN LAYER OF MERCURY. CHLORINE IS PRODUCED AT THE ANODE, AND SODIUM IS PRODUCED AT THE CATHODE WHERE IT FORMS SODIUM MERCURY AMALGAM WITH MERCURY. IT FURTHER DECOMPOSED INTO SODIUM HYDROXIDE AND MERCURY

LIME SODA PROCESS

THIS PROCESS DOES NOT USE ANY CELL TECHNOLOGY BUT BY SIMPLE REACTION BETWEEN CALCIUM HYDROXIDE AND SODIUM CARBONATE. CALCIUM HYDROXIDE IS CALLED MILK OF LIME AND SODIUM CARBONATE AS SODA ASH, HENCE THIS PROCESS IS KNOWN AS LIME SODA PROCESS. Na₂CO₃ + Ca(OH)₂ 2NaOH + CaCO₃ SODA ASH WITH CONCENTRATION 20% IS ADDED TO THE DISSOLVING TANKWHICH IS MIXED WITH STREAM OF WEAK LIQUOR THEN IT IS MIXED WITH SLAKED LIME.

THEY ARE HEATED TO 80-90℃ WITH INJECTION OF STEAM AND AIR IT IS CARRIE DOUT TILL THE EQUILIBRIUM IS ATTAINED. THE SLUDGE WHICH SETTLES AT THE BOTTOM OF THICKENER IS WASHED AGAIN AND SENT IT TO THE SECOND ONE TO REMOVE CaCO₃. SLUDGE MOSTLY CONTAINS CALCIUM CARBONATE. NaOH OBTAINED FROM THE OVERFLOW OF THE THICKENER IS CONCENTRATED TO THE REQUIRED CONCENTRATIONS.

DRAWBACKS IN CAUSTIC SODA PRODUCTION BY LIME SODA PROCESS DUE TO HIGH COST OF SODIUM CARBONATE THIS PROCESS IS NOT ENCOURAGED IN LARGE PRODUCTION. FOR INSTANT PREPARATION A SMALL SCALE OF THIS PROCESS WAS PRACTISED.

3) CAUSTIC STORAGE PRODUCTION AND HANDLING Caustic soda is produced in a fixed ratio of 1.128 tonnes per tonne chlorine produced. Under normal operating conditions mercury cell caustic soda contains 20-100ppm of sodium chloride. In case of diaphragm and membrane technologies the caustic soda is concentrated by evaporation before final storage.

4) CHLOR ALKALI PRODUCTS CAUSTIC SODA LYE. CAUSTIC SODA FLAKES. CHLORINE. HYDROGEN. HYDROCHLORIC ACID. SODIUM HYPOCHLORITE.

5) USES OF PRODUCTS CAUSTIC SODA LYE: IT FINDS USE IN ALUMINA REFINERIES, SOAPS,DETERGENTS,VISCOSE FIBRE AND NO OF OTHER APPLICATIONS. B) CAUSTIC SODA FLAKES: IT FINDS USE TEXTILE,SOAPS,DETERGENTS,PULP AND PAPER INDUSTRY.

C) CHLORINE: LIQUID CHLORINE IS USED IN MANUFACTURE OF HYDROGENATED FATS,DERIVATIVES AND EPICHLOROHYDRIN. D) HYDROGEN: HYDROGEN FINDS APPLICATION IN HYDROGENATION OF EDIBLE OILS FOR MANUFACTURING OF VANASPATI AND NON EDIBLE OILS.

E) HYDROCHLORIC ACID: IT IS USED IN PRODUCING FOOD INGREDIETS,ADDITIVES,METAL PICKLING, LATEX COAGULATION AND DYESTUFFS. F) SODIUM HYPOCHLORITE: IT IS AN EXCELLENT STERILISER, OXIDISER AND DECOLOURING AGENT. IT ALSO ACTS AS AN FOOD ADDITIVE.

6) ENVIRONMENTAL IMPACTS TOO MUCH USE OF DIAPHRAGM CELL CAN CAUSE LUNG DISEASES DUE TO ASBESTOS PRESENT IN IT. DUE TO MERCURY PRESENT IN THE MERCURY CELL FOR THE PRODUCTION OF CAUSTIC SODA IT CAN CAUSE VARIOUS CANCER. OZONE DEPLETION WOULD TAKES PLACE DUE TO PRODUCTION OF CHLORINE. AS CHLORINE IS HIGHLY REACTIVE IT SHOULD BE STORED IN NON CORROSIVE VESSEL.

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