Presentation on theme: "Fishbeck, Thompson, Carr & Huber, Inc. Application of High-Speed Turbocompressors at Municipal WWTPs in Michigan Jim Flamming, P.E., Senior Process Engineer,"— Presentation transcript:
Fishbeck, Thompson, Carr & Huber, Inc. Application of High-Speed Turbocompressors at Municipal WWTPs in Michigan Jim Flamming, P.E., Senior Process Engineer, Fishbeck, Thompson, Carr & Huber, Inc.
Aeration Blowers Aeration consumes 40-70% of energy used in activated sludge plants (WEF MOP OM-9) For supplying diffused aeration grids, 2 types: Positive Displacement Approx. 60% efficient Typically smaller (<100 hp) Output varies with speed, not pressure Factory or OEM packages available Widely applied, low capital costs
Aeration Blowers Multistage Centrifugal : Approx. 65-75% efficient Wide range of sizes, typ. >50 hp Output varies with pressure Widely applied for over 100 yrs. Can be more expensive initially than positive displacement PD and multistage blowers are the workhorses of the industry.
But Times Are Changing! With renewed emphasis on energy efficiency, new styles of blowers are starting to be applied. High speed turbocompressors offer several potential advantages over traditional blowers: Higher efficiencies Lower maintenance costs Variable output Quiet operation
High Speed Turbocompressors Operate at very high speeds: 25,000 to 45,000 rpm No contact bearing surface: magnetic or airfoil bearings No contact = no friction = no wear parts Oil free operation; no lubrication required or bearings to service Very low maintenance
High Speed Turbocompressors 10-20% improvement in efficiency Operate on VFDs; maintaining best efficiency at turndowns of up to 50% of max output No contact – very low vibrations – low noise (<70 dB at operating speed) Factory supplied package units with controls Typically small footprints
High Speed Turbocompressors Different styles from different manufacturers Magnetic Bearings – ABS/HST, Hoffman Revolution, Atlas Copco ZB-VSD; Spencer AyrJet Air Foil Bearings – HIS HT; K-Turbo; APG-Neuros; Turblex Magnetic bearings prevent any contact during operation, but typically cost more upfront Most are direct drive units; Turblex also provides a separately geared unit with additional control capability
ABS/HST Of the direct drive units, so far ABS/HST has the most installations in the U.S. at municipal WWTPs (61 units at 21 WWTPs, and 1300 units worldwide) Built in Sweden Only one with direct drive installations so far in Michigan, at three sites, which we will review as case studies
ABS/HST Five models 93-536 HP 600-10,400 scfm 5.5 – 18.2 psig discharge pressure
Fishbeck, Thompson, Carr & Huber, Inc. Case Studies Michigan WWTPs
Marquette WWTP Replaced RBCs with three plug flow 500,000-gallon nitr. basins; plus one 500,000-gallon WAS tank 1 50-hp and 1 75-hp blower to three 200-hp turbocompressors (ABS HST SP6000-1-L-5) each 4,337 scfm at 8 psig Start up July 2008
Coldwater WWTP Trickling filter-solids contact plant NH 3 violations, May 2007 Installed new IFAS, which required added aeration (presented in Session 1) Existing plant had two 75-hp, 900-scfm blowers
Coldwater WWTP Installed two 93-hp ABS/HST S2500-2-A-5; each 1,257 scfm at 8 psig Placed in new building; existing blowers remain as backup units City doesn’t have historical flow and hp draw data for blowers; difficult to compare
Reed City WWTP Three basin SBR plant Industrial/municipal WW Utilized three 150-hp PD blowers which had HIGH rates of failure Replaced units with four 111-hp HST S2500-1-H-5; each 1,969-scfm at 8 psig in new blower building
After installation, plant measured output: Old blowers rated for 3,000 scfm with two blowers running New HSTs – 3,600 scfm at 80 hp DO’s higher in SBRs Low noise Virtually no vibration Still in start-up; addressing electrical issues at site
Some Things To Consider… HSTs may not be suitable for every plant Relatively high initial capital costs; need to do a life cycle cost analysis; magnetic vs. air-foil Not cost-effective at lower HP requirements Would not want to parallel with PD blowers Sophisticated electronics, need to review existing electrical service and power quality Faults happen during start-up
Conclusions The world of wastewater treatment is changing New PLC-based controls open up the possibility for new kinds of technologies Offer better efficiencies and less maintenance While not for every application, HSTs offer some intriguing advantages that are worth consideration.
Fishbeck, Thompson, Carr & Huber, Inc. Any Questions? Thank you