Industrial electrolysis plants

Both Italy and Switzerland have work in progress on advanced alkaline electrolyzers. The DeNora Corporation and Brown Boveri of Italy and Switzerland, respectively, have built some of the largest industrial electrolysis plants and are each supporting in-house R D efforts, as well as working on contracts from their respective governments. 

An industrial electrolysis plant is considerably more complex. In addition to the basic tank arrangement—electrodes, electrolyte, separators to... 

More than 400 industrial water electrolyzers were in operation by the beginning of the nineteenth century. In 1939, the first large water electrolysis plant of 10,000 Nm3 H2/h capacity went into operation and in 1948, Zdansky/Lonza built the first pressurized industrial electrolyzer [1],... 

Since PV electrolysis plants are modular in design, it is possible to couple the expansion of PV electrolysis plants to growth in the FCV market. The creation of a H2 production and distribution system is contingent on the development of a working partnership between PV, electrolyser, automobile, pipeline, metal mining and retail fuel companies. The capital investments required for the construction of a PV electrolytic H2 production and distribution system is comparable to the capital investments in the construction of the cable and satellite infrastructure for the information technology industries in the latter part of the 20th century. 

Another Flemion which is suitable for the case where a caustic solution as low as 20% concentration may be utilized directly from an electrolysis plant on site, such as in the pulp industry, named Flemion 430, was also developed. This has an asymmetric structure, that is, the ion exchange capacity of the membrane surface facing a cathode is made lower than that of bulk membrane. 

Industrial scale electrolyzers were developed early in the 20th century for the manufacture of chlorine and caustic soda from brine, and for the commercial production of hydrogen used in ammonia synthesis. Large water-electrolysis plants were constructed in Norway and Canada in the 1930 s, based on cheap hydroelectric power, and the hydrogen so produced was used in fertilizer manufacture. With the advent of natural gas and low cost petroleum, hydrogen production moved toward catalytic steam-reforming of hydrocarbons, and water electrolysis became less significant. 

By the JAWE-process, now being introduced into the industrial production of future electrolysis plants, three fundamental major improvements have been achieved. 

A first ODC hydrochloric acid electrolysis plant in an industrial scale (10,000 and later 20,000 t/a chlorine capacity) is operated since 2003 and a first world scale plant (215,000 t/a) started in 2008. Further plants are under construction [4]. 

Normally the decision for a conversion is initiated by plans for an expansion of the production capacity or by environmental legislation. Each change in the plant structure or in the cost structure may lead to reevaluation of the future of the electrolysis plant. Therefore, each plant has to be considered individuaUy [190], [191]. For the European chlor-alkali industry a detailed analysis of the impact of a conversion of all mercury cells to the membrane technology on the competitiveness of the industry is given in [111]. 

World trade Most chlor-alkali electrolysis plants are situated in the vicinity of the chlorine users. The alkali users, particularly the alumina and pulp paper industries, are placed in the winning regions. Like the world trade with chlorinated hydrocarbons there are flows of liquid caustic soda with a volume between 2 and 3 million tonnes of NaOH (100%) per year. The net exporting regions are and will remain North America, the Middle East, Japan and Western Europe. Importing regions are South America (Surinam, Venezuela), Australia and South East Asia. 

Saline Water for Municipal Distribution. Only a very small amount of potable water is actually taken by people or animals internally, and it is quite uneconomical to desalinate all municipally piped water, although all distributed water must be clear and free of harmful bacteria. Most of the water piped to cities and industry is used for Htfle more than to carry off small amounts of waste materials or waste heat. In many locations, seawater can be used for most of this service. If chlorination is requited, it can be accompHshed by direct electrolysis of the dissolved salt (21). Arrayed against the obvious advantage of economy, there are several disadvantages use of seawater requites different detergents sewage treatment plants must be modified the usual metal pipes, pumps, condensers, coolers, meters, and other equipment corrode more readily chlorination could cause environmental poUution and dual water systems must be built and maintained. 

At present about 77% of the industrial hydrogen produced is from petrochemicals, 18% from coal, 4% by electrolysis of aqueous solutions and at most 1% from other sources. Thus, hydrogen is produced as a byproduct of the brine electrolysis process for the manufacture of chlorine and sodium hydroxide (p. 798). The ratio of H2 Cl2 NaOH is, of course, fixed by stoichiometry and this is an economic determinant since bulk transport of the byproduct hydrogen is expensive. To illustrate the scde of the problem the total world chlorine production capacity is about 38 million tonnes per year which corresponds to 105000 toimes of hydrogen (1.3 x I0 m ). Plants designed specifically for the electrolytic manufacture of hydrogen as the main product, use steel cells and aqueous potassium hydroxide as electrolyte. The cells may be operated at atmospheric pressure (Knowles cells) or at 30 atm (Lonza cells). 

In 1808, Sir Humphry Davy reported the production of Mg in the form of an amalgam by electrolytic reduction of its oxide using a Hg cathode. In 1828, the Fr scientist A. Bussy fused Mg chloride with metallic K and became the first to produce free metallic Mg. Michael Faraday, in 1833, was the first to produce free metallic Mg by electrolysis, using Mg chloride. For many years, however, the metal remained a laboratory curiosity. In 1886, manuf of Mg was undertaken on a production scale in Ger, using electrolysis of fused Mg chloride. Until 1915, Ger remained the sole producer of Mg. However, when a scarcity of Mg arose in the USA as a result of the Brit blockade of Ger in 1915, and the price of Mg soared from 1.65 to 5.00 per lb, three producers initiated operations and thus started a Mg industry in the USA. Subsequently, additional companies attempted production of Mg, but by 1920 only two producers remained — The Dow Chemical Co (one of the original three producers) and. the American Magnesium Corn. In 1927. the latter ceased production, and Dow continued to be the sole domestic producer until 1941. The source of Mg chloride was brine pumped from deep wells. In 1941, Dow put a plant into operation at Freeport, Texas, obtaining Mg chloride from sea-... 

Kenneth Warren. Chemical Foundations The Alkali Industry in Britain to 1926. Oxford Clarendon Press, 1980. Source for family shops changing to giant factories Liebig quotation plant sources of alkalis Leblanc s experiment Victorians like Leblanc factories reduction in hydrochloric acid pollution cost of pollution abatement electrolysis and 3 raw material units make 1 unit of product. 

A mixture of hydrogen and chlorine gas, eventually in combination with air, can be very explosive if one of the components exceeds certain limits. In chlorine production plants, based on the electrolysis of sodium chloride solutions, there is always a production of hydrogen. It is, therefore, essential to be aware of the actual hydrogen content of chlorine gas process streams at any time. There are several places in the chlorine production process where the hydrogen content in the chlorine gas can accumulate above the explosion limits. Within the chloralkali industry, mainly two types of processes are used for the production of chlorine—the mercury- and the membrane-based electrolysis of sodium chloride solutions (brine). 

Electrolysis has the potential advantage that a metal can be recovered in its most valuable forms as metal film or powder and sold or recycled to the process. Cf. also Walsh, Ref. [133]. Heavy metals, such as copper from metal complex dyes, or from catalysts in industrial effluents, have become a problem in clarification plants because of their toxic effects on microorganisms. Their disposal through deposition after chemical or physical treatment is senseless,... 

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