Pollution Engineering - April 2009 - (Page 32) Energy SAVINGS Service and maintenance In assessing the situation when asked to consult on the project, the RTO manufacturer estimated that the cost to repair the aging units would have been around $250,000. By making a decision not to invest in the old equipment, the company felt that they would achieve not only energy savings but also a significant reduction in maintenance costs going forward. “There’s really no comparison between the old and the new equipment,” said Bailey. “The old system had 42 hydraulic valves for controlling air flow, which were a maintenance headache. The new unit has a single rotating valve which requires minimal service and is a much simpler design.” Because the manufacturer’s payment depends on the system’s performance, it is critical from their perspective that they continuously monitor performance and regularly inspect and tune the system. Room to grow The company was pleased to discover they now had abatement capacity for a new production line, the exhaust from which could be routed to the old oxidizers. “While energy savings have been realized with the new equip…the average natural gas ment, what’s of equal savings exceeded the monthly importance is the fact that we have more oxipayment for the equipment. dizer capacity that will allow us to add new coating lines,” said Bailey. The company’s ment with the combustion chamber sitold oxidizers are still in place and ready ting atop 12 pie-wedge shaped ceramic to run. A new process could be con- media beds, all in a single can. The nected to them with just minor ductwork ceramic media bed area has also been changes. substantially reduced by the use of structured honeycomb ceramic blocks, which accomplish the same heat exchange at Technical advantages The new RTO system is about a quar- 50 to 100 percent higher velocity than ter the size of the old two-oxidizer randomly packed ceramic saddles. The RTO was delivered and installed system as a result of significant developments in RTO design over the last from November through December 2007, while the company continued production. Only five days of shutdown, split between two weekends, were required to complete the ductwork tie-ins to the existing process duct and existing stack, and to wire interlocks to the process. The RTO’s skid, including the rotary valve, drive system, combustion chamber support steel, gas train and control room, was completely assembled, prewired and pre-piped in the manufacturer’s shop. By implementing this RTO replacement project under an energy performance contract, the company was able, with no capital outlay, to expand their VOC capacity for future production lines, save more than $675,000 annually, replace aged equipment with a state-of-the-art machine, avoid $250,000 in repairs and get longterm supplier monitoring and service. PE 25 years. Whereas the old RTOs were arranged with seven horizontal flow ceramic media beds radiating outward around a central combustion chamber, the new RTO uses a vertical flow arrange- “ ” For more information, contact Jon Hommes, the lead engineer for Dürr Systems Inc., EES. His phone number is (734) 459-6800 and his email is jon.hommes@durrusa.com. Visit www.pollutionengineering.com to electronically forward a copy of this article to a colleague or customer. 32 Pollution Engineering APRIL2009 http://www.pollutionengineering.com
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