Chloro Alkali (CA) Process - Hanwha Chemical (Korea)

CA research center has been carrying out R&D in the CA (Chloro-Alkali) process and chemicals covering sodium hydroxide, chlorine, sodium chlorate, hydrochloric acid, ammonium chloride, and ECH. Recently,

Hanwha Chemical, the largest producer of CA chemicals, has successfully developed an energy-saving HCC electrolyzer and electroplating technology for cathodes and anodes, Hanwha R&D center is also conducting research on proton membrane used for polymeric electrolytes in fuel cells.

Korea Ministry of Science & Technology and Seoul Economy News nominated this fuel-cell technology as the one of the 100 best new technologies in Korea in December of 1999. CA research center is also allocating its resources in developing cost-effective and environment-friendly process and products mainly through electro-chemical procedure.

Electrolzyer

CA is an abbreviation of Chloro-alkali, and a broad term covering chlorine and caustic, or sodium hydroxide. Chlorine is the main raw material for PVC (Poly vinyl chloride), the widely used plastics.

Chlorine is also used for producing organic and inorganic chemicals, and also in bleaching, sterilization and water treatment. Caustic soda is used for producing organic and inorganic chemicals and soaps, and also heavily used in textile industry, pulp industry and water treatment.

Chlorine and caustic soda are made by electrolysis of brine, and its process schematic is shown in the following picture.

In the electrolysis process, the most important part is the electrolyzer, composed of frame, cathodes, anodes and membranes that separate these electrodes. Chlorine is generated on the surface of cathodes and caustic soda and hydrogen are generated on the surface of anodes. Due to the nature of process, reducing electricity by designing efficient electrolyzer is very important in this process. Hanwha Chemical had successfully replaced imported parts for electrolyzer with newly developed parts and also reduced utility costs.

Hanwha Chemical is currently carrying out a government funded research project of "Development of Electrolyzer for oxygen anodes". Once this project is finished successfully, one can run CA process at extremely low costs.

Electrode Coating

Hanwha Chemical, who leads domestic CA business, has been increasing quality of product by development, and trying to reduce on manufacturing cost. Anodes for CA and cathode, the core part of electrolysis facility, are important elements to decide electrolysis cost reduce.

Some of the electrode for CA (chlorine / anhydrous soda) is applying at our factory. We have developed and commercialized electrode such as EGL (Electro-Galvanizing line), ETL (Electro-Tinning line), ECL (Electro-Copper line) on base of accumulated techniques.

The Electro-Galvanizing line for car sheet steel, Electro-Tinning line for drinking can, and Electro-Copper line for printed circuit board are used the unplanted sheet steel as cathode, and used noble metal as anode.
These processes use electricity a lot, so reduce on the cost is pending problem by electrolysis voltage strengthening and durability improve. Our company tries to develop anode for EGL/ETL/ECL in order to increase sales amount base on electrode for CA development.

To improve the durability problem, we manufactured an electrode by applying coating surface morphology design. Sol-gel, manufacturing method for coating solution the liquid for coating by sol-gel process react as a sector or ring shape become a polymer, if you coat with it and dried, an oxide polymer(glass) forms.

The glass oxide layer is excellent in adhesion with Ti, and expecting to prevent base Ti corrosion by penetrates acid because of the layer’s delicacy. The manufactured electrode was compare and watched the corrosion of the electrode.

Also, its surface was treated for expansion of active layer surface and adhesion improvement of Ti substrate, the base plate of electrode. The developed electrode is improved 40~60% more of life time than ELTECH company’s electrode of America. We have supplied it to Hyundai steel pipe, Il Jin, POSCO, Dong Bu steel, Tea Yang metal and now we are monitoring the product.
The developed electrode has almost no crack as seen on the picture, and it can maintain long life time in harsh corrosion and acid because it combined hardly with titanium, shows delicate structure.

Specialty

Hanhwa Chemical R&D center has developed a manufacturing technique of membrane for polymer electrolyte membrane fuel cell. It is clean high efficient energy source for electric automobile engine, small break up power, portable and battery replacing power. As it is well known to be commercially used in near future, automobile makers, oil companies, chemical companies, catalyst companies, and electronic companies are actively research and developing it.

.The company has been developing the core part, PEM of PEMFC based on technologies of electric chemical, high molecule synthesis, and processing. And the company also practiced government’s programs such as “development of fluorine material for proton exchange layer” (1995-1996) and G7 business “development of 5KW solid high molecule energy fuel system”(1996-1998, cooperated with Korea institute of energy research).

The main techniques of this development are over fluorine sulfonic acid type Monomer and cooperate with TFE technology, film fabrication technology of copolymer, and proton exchange technology. The product from our company, membrane for PEMFC, the unit weight(EW) 1000-1100. in case of layer, proton conduction at normal temperature is 0.09-0.1S/?. With condition of EW 1020, 100? thick of layer 80?, 1atm, the result of single FEMFC battery turns out to 970 mA/cm2 at 0.6V.

It was better than commercial layer 810mA/cm2 of Dupont Company’s Nafion 115. The corporately developed with KIER “development of fluorine material for proton exchange layer” was selected as one of the top 100 technology of Korea on Seoul economy and Ministry of Science & Technology news paper issued on Dec. 1999.

Our company will not satisfy with these results, but keep try to have the best efficient membrane for PECFC in the world. We are groping to have cooperation with competitive organizations related to these fields.

Reference :
Web site http://research.hanwha.co.kr

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