Xerolyt® EXTRA Electrodes Optimize
A large chemical plant in Germany has been using Xerolyt pH electrodes in various process steps. Important is the very low maintenance requirement: no pressurization of the electrolyte shall be needed and no diaphragm contamination shall occur.
The international PVC market
The PVC industry is emerging again from several weak years in terms of profitability. Economic growth of 2.8% per annum from 1999 - 2004 is forecast to accelerate to 3.6% from 2004 through 2009. Global PVC demand recovered in 2004 and is forecast to continue to grow at a rate of 4.1% per year through 2009. China will be the key country for world demand and supply issues. China is planning on adding most of the world’s new PVC capacity over the next few years.
PVC production process
PVC, first synthesized in the laboratory in 1903, is made through polymerization of VCM (vinyl chloride monomer) which is made from ethylene and chlorine. In two simultaneous processes, 1.2-dichloroethane (EDC) is produced. Through “direct chlorination”, EDC is produced from ethylene and chlorine at approx. 60 °C (140 °F) in the presence of an iron compound catalyst. In a cracking unit EDC is converted to VCM under formation of hydrogen chloride HCl.