Chlorine consumption

United States Caustic Soda Production. In 1987 U.S. production of caustic soda increased to 10.4 million tons (fig. 1), more than 10% over that of the previous year, furthermore, 1988 production was up another 6.7% to 11.1 million tons. The demand for caustic soda has been very strong in recent years as evidenced by both increased U.S. consumption and a strong export demand. In 1987 the United States exported 1.5 million tons, 14.5% of the total caustic soda production (6), representing a 25.5% increase over exports in 1986. Then, in 1988, caustic soda exports grew by another 4.1%. A weak doUar helped boost the 1987 exports. Growth slowed in 1988, however, as a result of an industry (and world) wide caustic soda shortage, which was caused by lower U.S. chlorine consumption and forced allocations. Because industries switched from caustic to soda ash where possible, the lower 1988 export growth was not indicative of caustic soda s export potential. 

Category includes only direct chlorine consumption the majority of consumption is included in Epichlorohydrin, propylene oxide. 

Major Chlorine Markets. Forecasted changes in chlorine consumption (Table 23) are addressed below in descending order of the importance of the major derivative, based on 1987 demand. 

Caustic Soda to Chlorine Balance. In 1988, the ratio of U.S. caustic soda to chlorine consumption was 0.96 1 (see Fig. 39). Since 1968 this ratio has ranged from alow of 0.88 1 (1978 and 1981) to a high of 0.98 1 (1969). No single factor can explain these variations, since caustic soda and chlorine, with few exceptions, have different markets and are therefore not driven by the same economic forces. This ratio is expected to trend upward over the next five years, however, since caustic soda consumption in the United States is forecasted to grow somewhat faster than chlorine consumption. It is expected that this ratio will remain within the range experienced in 1970—1990. Because caustic soda is co-produced with chlorine at a theoretical ratio of 1.1 1, a U.S. consumption ratio below that level results in excess avaHabihty of caustic soda. This material is typically shipped offshore to fill a significant export demand, and in 1988, for example, net U.S. exports of caustic soda amounted to 7.1% of production. 

Sodium Hydroxide. Before World War 1, nearly all sodium hydroxide [1310-93-2], NaOH, was produced by the reaction of soda ash and lime. The subsequent rapid development of electrolytic production processes, resulting from growing demand for chlorine, effectively shut down the old lime—soda plants except in Eastern Europe, the USSR, India, and China. Recent changes in chlorine consumption have reduced demand, putting pressure on the price and availabiHty of caustic soda (NaOH). Because this trend is expected to continue, there is renewed interest in the lime—soda production process. EMC operates a 50,000 t/yr caustic soda plant that uses this technology at Green River it came onstream in mid-1990. Other U.S. soda ash producers have aimounced plans to constmct similar plants (1,5). 

Two oxidants commonly used are chlorine and potassium permanganate. The Roe chlorine number, the uptake of gaseous chlorine by a known weight of unbleached pulp (ie. Technical Association of the Pulp and Paper Industry (TAPPl) Standard Method T202 ts-66) has been superseded by the simpler hypo number (ie, TAPPl Official Test Method T253 om-86), eg, chlorine consumption in treatment of the pulp with acidified sodium or calcium hypochlorite. 

A study of the North American bleaching agent market was completed in June 1988 and includes consumption quantities for the year 1986 (156). Chlorine consumption for 1986 was 1.86 x 10 t. The North American consumption volume of other chlorine-containing bleaching compounds including sodium and calcium hypochlorite, chlorinated isocyanurates, and hydantoins was 286,000 t. The 1986 North American consumption of sodium chlorate was estimated at 5.5 x 10 t. 

Another reducing agent relevant to chlorination reactions is sulfur dioxide. When the material to be chlorinated contains calcium oxide, it is advantageous to convert it to calcium sulfate rather than to calcium chloride. The advantages are less chlorine consumption and easy disposal of calcium sulfate (which is water-insoluble). The chlorination of scheelite is an important example of the use of the sulfur dioxide chlorine reagent ... 

Figure 10.32 Rates of increase of whiteness, AOX content and chlorine consumption with time of bleaching [247]...

Many of the changes in chlorine consumption in the past ten years have arisen out of the environmental concern about the use of chlorine in some processes such as pulp and paper as well as the concern of the loss of the ozone layer with the use of CFCs. 

These pressures have worked their way through the chain and now we have no chlorine consumption in pulp production in Europe and a much diminished consumption of chlorine in the HFC precursors. In addition the solvents sector saw a reduction in the demand for chlorine as many solvent applications changed. 

Two-thirds of the chlorine produced in North America is consumed by the organic chemicals industry (25% goes to ethylene dichloride production alone). Pulp and paper mills account for another 15%, while 5% of the total is used in water treatment. All of these applications, however, have environmental implications that led to demands from activist groups that the production of chlorine derivatives be reduced (even, in the extreme view, phased out entirely). While these concerns are being taken seriously in all quarters, and some chlorinated products have already been banned, the fact is that chlorine-based technologies make, and will continue to make, important positive contributions to human health and prosperity. Indeed, at the time of writing in 1996, chlorine consumption continues to rise, al-... 

A system consisting of a column and a cooler, produces a material characterized by density as a system response. The density of the observed product is affected by six factors X chlorine consumption X2 water consumption in the column X3 phleg-matizer consumption X4 temperature in column X5 level of liquid in column and X6 water consumption in cooler. The opinions of four researchers are given in Table 2.13. Check the concordance of the researchers opinions. 

The apparatus for the chlorination of titanium raw stock in a fluidised layer is a cylindrical shaft lined with thick silica brick. There are several shelves with gas distribution grates located one above another for better chlorine consumption and titanium extraction. The parent mixture is loaded onto the top shelf where it is partially chlorinated with unreacted chlorine coming from below and is sent onto the next shelf through a pipe. The most intensive chlorination occurs on the lower shelf. 

In fact, active chlorine consumption was observed in disturbed experiments with higher C102 concentration. Chemical formation from active chlorine and chlorite is also favoured due to the reaction behaviour after switching off the electrolysis experiments (Fig 7.11). It can often be seen from the UV spectra that the hypochlorite peak decreases and the C102 peak slightly increases. Increase of C102 concentra-... 

Bergmann, M.E.H., Rollin, J., Koparal, A.S. and Kresse, K. (2006b) What is the ominous chlorine consumption in the disinfectant production from drinking water electrolysis Proceedings 57th Annual Meeting of the International Society of Electrochemistry, 27 Aug. to 1 Sept., Edin-burgh/UK, p. S5.0-4. 

Kraft, A., Blaschke, M., Kreysig, D., Sandt, B., Schroeder, F. and Rennau, J. (1999b) Electrochemical water disinfection. Part II Hypochlorite production from potable water, chlorine consumption and the problem of calcareous deposits. J. Appl. Electrochem. 29, 895-902. 

This type of solution method is possible for reactions where deactivation is slow, and a pseudo steady-state assumption can be made when solving the mass balance equations. Thus, these equations are applicable to reactions where the activity loss is first-order in both the poison and the active sites, and where deactivation is slow compared to the main reaction. A similar type of approach was taken by Johnson et al. (5), for oxygen consumption and carbon content during catalyst regeneration and by Bohart and Adams (6), for chlorine consumption and absorbence capacity of charcoal. 

A series of works [124-128] applied a combination of the chlorine consumption spectrophotometry and organic radical concerntration change evaluation by ESR spectra in the process of photolysis and after it. 

Figure 7. Temperature dependence of quantum yield of chlorine consumption in reaction of methane photochlorination in structurally nonequilibrium glassy mixes of reactants (1) structurally nonequilibrium mix of reactants prepared by rapid spraying at 22 K (2) same mix after thermal annealing at 30-40 K (3) same mix after ultrasonic treatment at 22 K.

The anodic charge-transfer resistance could be extracted from the fitting procedure. Thus the method provided a reliable value of the corrosion current and rate. This corrosion rate is about 10 micrometers per year, which is not negligible if the chlorine consumption is considered. 

In the year 2004, the global demand of chlorine was 48.4 x 106 metric tons, more than 95% thereof by the electrochemical means described as follows. The percentage of world chlorine consumption in 2004... 

The aim of accelerated bleaching is to adopt a continuous bleaching by reducing the bleaching time and chlorine consumption with the help of more reactive bleach liquor. However, the accelerated bleaching may lead to degradation and yellowing of the cotton fabric. 

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