New compressors boost energy savings

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 contacted Atlas Copco to obtain a tailor-made solution.
 
The units at the site consisted of two turbo compressors and four old oil-free reciprocating compressors that supplied 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 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.
 
Engineers were tasked with accomplishing the changeover without shutting down production, which was successfully done due 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.
 
The central compressed-air unit offers EMS-Chemie a saving in electricity consumption of 10%, and the new cooling water system reduces water use 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. Energy efficiency is simply better. That is exactly what we need.”