Chlorine production capacities

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). 

The chlor-alkali industry in Australia is dispersed, with chlorine production capacity of 127 000 tonnes per annum from a total of nine plants spread across the country. 

Of the chlorine production capacity installed in Germany, which totalled 4.4 million tonnes in 2003, 50% were from the membrane cell process, 27% from the mercury cell process and 23% from the diaphragm cell process. The mercury cell process has been the subject of environmental policy criticism for years because of its use of mercury cathodes and resulting pollutant emissions. Hence, no new mercury plants will be... 

Due to its high vapor pressure at the operating temperature of the electrolysis, mercury, whose circulating tonnage represents 700 to 2400 kg/t per day of chlorine production capacity, pollutes the different gaseous streams produced (chlorine, hydrogen). Similarly, it contaminates the different liquids produced by the operation (spent brine, caustic soda, etc.). This results in substantial losses, which must be limited for economic as well as environmental reasons. Whereas small. amounts of mercury in the chlorine (0.1 to 0.2 g/t) are not detrimental to its subsequent uses, the same cannot be said of caustic soda, especially for food applications, in which it is removed by filtration (up to 15 ppb), for hydrogen, from which it is removed (up to 3 to 5 ppb) by absorption in sodium hypochlorite, adsorption on activated charcoal etc, and aqueous wastes, from which it is removed (up to 5 to 10 ppb) by precipitation, adsorption, reduction or extraction. The spent brine, which normally contains 1 to 10 ppm mercury and occasionally 1000 ppm, is usually recycled and therefore does not require treatment... 

The total mercury loss is thus up to 2 to 3 g/t of chlorine produced. US regulations stipulate that the daily release must not exceed 23 kg, corresponding to the normal operation of a plant with a chlorine production capacity of 1000 t/day. This regulation is expected to be even more stringent in the future (maximum daily release about 1.1 kg). 

Chlorine is one of the most important base chemicals in chemical industry. The worldwide chlorine production capacity in 2008 was... 

Figure 108. Chlorine production capacities by economic regions (1983 and 1997)...

Opeiating capacity as of Match 1989. Idled capacity is noted where information is available. Refers to year chlorine production started at location. 

Synthesis from Hydrogen and Chlorine. Less than 10% of the U.S. production capacity of HCl is made by the direct reaction of the elements. 

Over 90% of the HCl produced ia the United States origiaates as a coproduct from various chlorination processes direct generation of HCl from and CI2 accounts for only about 8% of the total production. Table 11 describes the production contribution of HCl from significant sources through the period 1980 to 1992 (72). Figure 6 illustrates the historical production growth of HCl ia the United States (73). The growth rate, about 5—6% from 1955 to 1975, slowed to - 1% because of disparity between supply and demand (see Table 12). The production capacity ia 1993 was about 2.92 million metric tons, down 9.6% from the 1992 production of 3.24 million metric tons (74). 

Economic Aspects. Sodium chlorate production has grown at about a 5% rate since the early 1970s and is expected to grow at 8—10% through 1995. The projected rapid growth is related to the increased use of chlorine dioxide in the pulp and paper industry. The 1991 production capacities of various North American plants are given in Table 7. The price of sodium chlorate has increased from 165/t in 1970 to about 480/t in 1991 (113,114). 

Producers. In the years since 1945, production capacities and the number of producing companies have substantiaHy increased however the high temperature chlorination reaction has remained the exclusive technique for commercial production of aHyl chloride. Production facHities thought to be in existence in 1990 are Hsted in the foHowing, in order of estimated production capacities (40—48). 

World production of Bra in 1990 was about 438 000 tonnes pa, i.e. about one-hundredth of the scale of the chlorine industry. The main producing countries are (tonnes) USA 177000, Israel 135 000, Russia 60000, UK 28 000, France 18 000 and Japan 15 000. The production capacity of Israel has recently increased almost threefold because of expanded facilities on the Dead Sea. Historically, bromine was shipped in individual 3-kg (net) bottles to minimize damage due to breakage, but during the 1960s bulk transport in monel metal drums (100-kg capacity) or lead-lined tanks (24 or 48 tonnes) was developed and these are now used for transport by road, rail and ship. The price of Bra in tank-car lots was 975/kg in 1990. 

The use of mercury for extracting precious metals by amalgamation has a long history and was extensively used by Spain in the sixteenth century when her fleet carried mercury from Almaden to Mexico and returned with silver. However, environmental concerns have resulted in falling demand and excess production capacity. It is still used in the extraction of gold and in the Castner-Kellner process for manufacturing chlorine and NaOH (p. 72), and a further major use is in the manufacture of batteries. It is also used in street lamps and AC rectifiers, while its small-scale use in thermometers, barometers and gauges of different kinds, are familiar in many laboratories. 

The plant capacity for all waste types together will be around 45,000 tpa. It will have a heat production capacity of 25 MW at 7,500 productive hours a year. The plant can also accept PVC. Eor such solid chlorinated waste at most 15,000 tpa/yr capacity is available. This has been based on a test with a DOW kiln in Stade, Germany. The BSL plant has been operational since mid 1999. 

Plant location Capacity (tonnes per annum as chlorine) Products Comments... 

Krupp Uhde has more than 40 years of experience in the design and construction of chlorine/caustic soda plants [1]. The company s 150 plants throughout the world have an overall production capacity of approximately 8 million metric tonnes per year of NaOH (100%) and thus make Krupp Uhde unique in its field. 

Measurements taken in the plant show that the formation of chlorine dioxide is dependent on temperature, production capacity, hypochlorite concentration, caustic concentration and residence time of the hypochlorite in the reactor at step one. 

For the steady-state situation, chlorine dioxide emissions are measured when altering process variables such as concentration, temperature and production capacity. These measurements result in a number of relationships, plotted in Figs 25.2 and 25.3, with respect to the hypochlorite installation. 

Figure 25.2 shows that the emission of chlorine dioxide strongly increases with increasing temperature and is linear with increasing production capacity under the steady-state condition. In Fig. 25.3 it is seen that emission increases with increasing... 

The time elapsed between the start of the peak in the chlorine feed and the increase of the chlorine dioxide emission is about 2 min. The height of the peak is dependent on the reaction temperature, hypochlorite concentration, production capacity, gas... 

When the capacity is increased under the same process conditions the caustic concentration is increased on higher dosing. As the quantity of free caustic in the end-product and in the liquid flow of the jet-loop reactor is the same, the percentage of caustic reacting with chlorine increases by roughly 25-60% when the production capacity is increased. Depletion of caustic at the liquid-gas interface can then occur more easily. 

Dichlorobenzene is currently produced by 3 U.S. companies at 3 different locations Monsanto Company, in Sauget, Illinois PPG Industries, Inc., in Natrium, West Virginia and Standard Chlorine of Delaware, Inc., in Delaware City, Delaware (SRI 1997). Current annual production capacity for the Monsanto Company, PPG Industries, Inc., and Standard Chlorine Chemical Company is 33, 36, and... 

Chlorobenzene is produced by three United States chemical companies Monsanto Chemical Company, Sauget, Illinois PPG Industries, Inc., Natrium, West Virginia and Standard Chlorine Chemical Co., Inc., Delaware City, Delaware. Production capacity for chlorobenzene at these plants has remained constant since 1985 although it appears that actual production has declined slightly during that period (Hughes et al. 1983 SRI 1985, 1986, 1987, 1988 USITC 1988). 

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