Chlor-alkali electrolysis produces the important commodity chemicals chlorine, hydrogen and caustic soda from sodium chloride and water. The purity of the end products is central to all the process stages. The basic substance is brine. At the start, the brine saturation is set by precipitation, filtration and preliminary purification of the brine. As the electrolysis consumes vast amounts of energy, process efficiency is of particular importance. The modern membrane electrolysis process, which is becoming increasingly popular across the globe, uses much less energy and is less polluting than conventional electrolysis processes – while maintaining a similar level of purity of the end products dry chlorine, hydrogen and caustic soda. However, the membrane process requires the brine used and circulating in the process to be of very high quality. Furthermore, all of the processes attempt to separate the chlorine gas produced from the hydroxide to effectively avoid a back reaction from chlorine to chloride and hypochlorite, as this would contaminate the caustic soda. One of the key process parameters here is the optimal temperature setting. All of this is crucial for composition and concentration of the caustic soda formed.

KROHNE's sophisticated measuring technology is part of the state-of-the-art equipment featured in the superior process technology used in chlorine chemistry. For example, the Coriolis mass flowmeters work for aggressive media such as caustic soda virtually without pressure loss and also feature ultramodern diagnostics functions and digital communications options. Our pressure transmitters feature an impressive robust design for measurements in complex process pressure and level applications, for example in the chlorine tank. And KROHNE's variable area flowmeters can be used to measure the flow of both chlorine gas and liquids. Integrated electronic equipment and application diagnostics in these devices can detect fouling, as well as pulsating flows or gas compression oscillations and even blocked floats. This results in unprecedented reliability.