Chlorine balances

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. 

In contrast, an iron oxide carbon composite has been reported that is highly effective in removing both bromine and chlorine from a blend of brominated HIPS and PVC in the course of catalytic thermal degradation, with respect to the liquid fraction of the products of pyrolysis (52). The amounts of chlorine and bromine in the solid have been given. However, a through chlorine balance has not... 

Table 5 gives a summary of the chlorine balances obtained Both CO and CO were formed over this catalyst, with the proportion of CO constant with time-on-stream at 23% of the total CO. ... 

Chlorine balances for catalyst B Fluid-bed oxidation of feed B... 

The presence of various chloride species in the PPY/chloride complex further suggests that any reaction stoichiometry based on the total chlorine balance of the complex can be quite misleading. For example, at least two reaction schemes which give rise to complexes which pyrrole CP ratios of 3 1 [88] and 4 1 [89] have been proposed. However, from the actual chloride anion content of the complex and the corresponding amount of deprotonated pyrrolylium nitrogens ( 25%) after complete base compensation of the complex, it appears that the reaction stoichiometry corresponding to 25% oxidized pyrrole units in the complex is more appropriate. 

A chlorine balance in the raw fluff has been reported [2] and chlorine recovery had reached 94.95% as 9.6% hydrochloric acid. Recently, calcium hydroxide is added to the fluff as in the Sapporo Plastic Recycling Center to stabilize the operation. The recovery of HCl decreased greatly from 5.4 to 1.2%, as shown in the material balance in Figure 26.3 and is discarded after neutralization. 

Prutton, Turnbull and Dlouhy [36] studied the chlorine balance in the thermal decomposition of oil solutions of chlorinated additives in the presence and the absence of iron powder. A summary of their results is shown in Table 11-10. The effect of iron in promoting the loss of chlorine from chlorinated paraffin wax is evident at both 473 K and 523 K, the reaction being more pronounced at 523 K. On the other hand, iron has no influence on the decomposition of chlorine tightly bound to the... 

The addition of hexane and toluene also had a beneficial effect. Over Pd/AbOs the amount of C2CI4 formed was 40 times lower in the presence of hexane whilst it was 20 times lower with toluene added. C2CI4 formation was also inhibited and it was apparent that the production of CI2 was suppressed. It was also noted that the chlorine balance was often low, suggesting that chlorine was retained by the catalyst and this eventually could lead to deactivation. 

The management of the hydrochloric acid streams plays a decisive role for the equilibrium of the chlorine balance of an economic region. It is estimated, that in Europe one third of the total chlorine demand is covered by HCl [338), see Chapter 14.8. 

In the past the chemistry with chlorine was discussed mostly in an emotional manner because reliable figures were scarce or not available. In order to provide an unbiased base for fact-orientated debates with authorities and in the public, chlorine balances have been prepared since the beginning of the nineties, giving informations about the quantities of material flows as well as their structures. 

The chlorine balances for Western Europe in 1992 and 1995 are described as an example [386]. The usefulness of such balances depends on the access to realistic data from competitive companies. ECOTEC in Munich, an independent consultant collected all necessary data in cooperation with the chlorine producing and using companies (21 companies with 83 production sites), checked the data and aggregated them to establish the balance. 

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