The Swiss chemical group EMS-CHEMIE, an industry leader in the speciality chemicals and polymer materials field, has put its trust in Atlas Copco. In 2012 Atlas Copco supplied two type ZH 15000 oil-free centrifugal turbo compressors, including dry coolers and pumps, for a new cooling-water circuit. The units provide compressed air for the plant air supply and for nitrogen production at the Domat/Ems production site. Atlas Copco also consulted on the ideal solution for optimizing the site’s infrastructure.
The high-performance polymer specialist, whose products are used in areas such as the automotive and mobile phone industries, presented Atlas Copco with an ambitious challenge. The compressed air supply for the plant air and the air separation system needed improving, while the new compressed-air unit required installation of a new cooling system. The challenge was to carry out the work without a moment’s interruption of production.
The needs at the Domat/Ems production site are enormous. Every year 74,000,000 Nm3 of compressed air is required for the plant air supply and 69,000,000 Nm3 for the production of nitrogen. In 2010 it became apparent that the existing systems were approaching capacity and would be unable to meet production requirements much longer. When one of the six compressors broke down, EMS-CHEMIE engineers questioned the existing concept as well as the planned capacity increase. They investigated a redesign of the entire system and contacted Atlas Copco to obtain a tailor-made solution to suit their needs and to optimize the entire infrastructure.
The existing unit consisted of two turbo compressors and four old oil-free reciprocating compressors that supplied the two compressed-air networks operating at different pressure levels (plant air and nitrogen production). The two turbo compressors, one from another supplier and a type ZH 10000 geared turbo from Atlas Copco, were retained to ensure security of supply and because they complemented the two new type ZH 15000 geared turbo compressors.
The two new compressors supply both the plant air and the compressed air for the nitrogen production at different pressure levels in an optimal and efficient range. Furthermore, the plant air network was expanded with an additional adsorption dryer to meet the increasing requirements for compressed air.
The engineers were tasked with accomplishing the changeover without shutting down production, which was successfully done thanks to meticulous planning and precise execution. The first step was to install a new, closed cooling-water circuit with a dry cooling capacity of 3 MW and then to lay the new pipework system in the central compressed air unit. The new compressed-air unit was set up alongside the old compressors.
“We prepared a complete parallel system and then swapped over the unit, one machine at a time, ensuring that round-the-clock production was maintained.” explained Josef Wolf, Project Manager at EMS-CHEMIE. “With Atlas Copco at our side, we had an outstanding partner who always came up with a solution when problems were encountered.”
Focusing on energy savings
The state-of-the-art central compressed-air unit offers EMS-CHEMIE a saving in electricity consumption of 10%, and the new cooling water system reduces water usage by up to 75%. “The question of energy requirements was our prime concern, and here, too, we are more than satisfied,” summed up Martin Schlumpf, Energy Manager at EMS-CHEMIE. “The Atlas Copco ZH 15000 produces less waste heat and consumes less energy with the same output. Their energy efficiency is simply better. That is exactly what we need!”