Hydrogen production chlor-alkali cells

The products of the electrochemical reactions in a chlor-alkali cell are the same as the electrode products in a chlorate cell. Thus, both types of cell generate chlorine at the anode and hydrogen and hydroxyl ions at the cathode. In the chlorate ceU, the products... 

Electrolytic Preparation of Chlorine and Caustic Soda. The preparation of chlorine [7782-50-5] and caustic soda [1310-73-2] is an important use for mercury metal. Since 1989, chlor—alkali production has been responsible for the largest use for mercury in the United States. In this process, mercury is used as a flowing cathode in an electrolytic cell into which a sodium chloride [7647-14-5] solution (brine) is introduced. This brine is then subjected to an electric current, and the aqueous solution of sodium chloride flows between the anode and the mercury, releasing chlorine gas at the anode. The sodium ions form an amalgam with the mercury cathode. Water is added to the amalgam to remove the sodium [7440-23-5] forming hydrogen [1333-74-0] and sodium hydroxide and relatively pure mercury metal, which is recycled into the cell (see Alkali and chlorine products). 

The most frequent synthetic use of electrolytic hydrogen is the production of HCl, which is covered in Section 9.1.9.2. This is a natural outlet for a chlor-alkali producer, who can use HCl to acidify cell feed brine or depleted brine and to regenerate ion-exchange columns. It also allows profitable use of the chlorine contained in the liquefaction tail gas. The HCl that can be consumed internally, and so the amount of... 

Hydrogen evolution reaction (her) is one of the most frequently occurring cathodic reactions in industrial cell processes. Hydrogen is formed as a by-product in the chlor-alkali process and in the chlorate production, which are the major industrial electrochemical processes [1], but it is the desired reaction in water electrolysis. Traditional cathode materials for industrial applications have long been iron and mild steel. But, with the increasing cost of electrical power and especially... 

A marked fraction of the plants were built using PEMFCs, which cost more than other fuel cell systems. A wider use of such fuel cells is probably justified in those cases where a cheap source of highly pure hydrogen is available, such as close to chlor-alkali industries, where pure hydrogen is a free by-product. 

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