This page contains a Flash digital edition of a book.
Process Equipment Update


project it has just completed for a major food processor in the USA.


In an effort to prevent steam trap failures the company had already implemented a preventative maintenance (PM) schedule. However, with close to 100 traps in the plant, PM could only be performed once per year – taking up to 100 hours in total.


For steam trap monitoring, the company decided to install nine 708 Rosemount wireless acoustic transmitters which provide acoustic event detection, including leaks in steam traps and pressure relief valves.


These were placed on steam lines throughout the plant and integrated into the existing Smart Wireless Gateway, which communicates to a plant host system, data historians or energy management software.


Unparalleled visibility The 708 transmitter, with a combination of temperature measurement and acoustic ‘listening’, gives unparalleled visibility into steam trap states.


“Manual monitoring of temperature did not give us enough information to conclusively target a steam trap for replacement when we saw water- hammering,” reported a project engineer from the food processing company. “But when we installed the wireless acoustic transmitter, we could tell immediately which steam trap was stuck.”


This problem was quickly fixed, and a trend of the new trap showed normal acoustics and temperature.


Now the plant has real time alerts for each of the nine steam traps with wireless acoustic transmitters. Some are in wash down areas, and one is in a high humidity environment. All are communicating reliably.


Overall the food processor has managed to reduce energy use by minimising steam blow-through and/or blocked flow; improved productivity by eliminating preventative maintenance activities on steam traps; and reduced mechanical/ asset failures by minimising water- hammering. l


Steam trap assessments are crucial S


o concerned was the US Department of Energy (DOE)


about energy wastage that it launched a Save Energy Now campaign to highlight the issues involved. As part of this campaign, the DOE performed a steam assessment at Dow Chemical’s plant in Hahnville, Louisiana, USA. The main objective was to identify opportunities for natural gas savings in the plant’s steam system.


The key findings of the assessment included: quantifying potential energy


12 www.engineerlive.com


savings, especially with the assistance of an outside expert, can provide the impetus for management to take action. Although Dow Chemical had an active energy management programme, the Save Energy Now assessment was able to uncover substantial additional opportunities for energy savings by focusing on a specific system; repairing leaks and failed steam traps. The personnel at the site improved their steam trap programme and enhanced their leak repair campaign.


Although Dow was aware that the efficiency of these systems could be improved, the assessment quantified the potential energy savings in a manner that made it more compelling to implement the improvements.


The combined annual energy and cost savings resulting from these two efficiency measures amounted to 272,000 MMBtu and US$1.9 million, respectively. With project costs of approximately US$225,000, the simple payback was around six weeks. l


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39