Wide Flow Channels 
The patented parallel-plate design of MLM lets air flow through uniform straight channels, unlike saddles that make the air turn repeatedly as it flows through irregular passages that are narrow in places. Wood dust that would lodge in tight gaps between saddles passes right through MLM into the combustion chamber and burns up. In severe applications involving large particles or sticky condensibles, it may be necessary to pre-filter the air through high-efficiency cyclones, wet electrostatic precipitators and/or mist eliminators.

Proven in the Field
MLM's ability to resist plugging was demonstrated at the Hatfield, Pennsylvania Wastewater Treatment Plant, where an 8,000-scfm 3-canister RTO is used to destroy VOCs and odors from the exhaust of a multiple-hearth sludge incinerator.

A Challenging Application
When those RTO canisters were packed with 1" ceramic saddles, the pressure drop crept up constantly, increasing fan

power consumption and requiring frequent washing and replacement of the saddles. Even though the pre-filtering system included a venturi scrubber and a wet ESP, enough fine ash particles got into the RTO to require wash-out of the saddle beds every 11 to 14 days, whenever the pressure drop reached 10" per canister. The washing process took about 18 hours, usually on premium overtime pay.

Media Change OutCuts DP
In 1998, 4 ft of MLM-180 was installed to replace 8 ft of 1" saddles in each canister. Thermal efficiency remained at 95% thanks to MLM's higher heat capacity, and stack emissions stayed in compliance. The pressure drop across each canister dropped to under 1.5", providing an enormous savings in electric power use. Maintenance costs savings were even greater. The MLM only has to be washed out two or three times a year. Each washing has returned the pressure drop to under 1.5" per canister, unlike the saddles whose pressure drop after washing grew higher every time, until they eventually had to be replaced.

Wood Industry RTO Test
MLM has also passed a nearly 2-year test in an RTO canister at an oriented strand board plant. Dryer exhaust passed through a well-maintained cyclone and wet ESP, where the voltage was always above 50 kV and the wash water was kept at low TDS. The MLM-200 bed showed a pressure drop of 9" initially, which increased to 12-13" before washing - vs. 20" initially and 30" before washing when the same canister had been packed with saddles.