WO2004108610A1 - Combination of compressor and permanent magnet motor for sewage aeration - Google Patents
Combination of compressor and permanent magnet motor for sewage aeration Download PDFInfo
- Publication number
- WO2004108610A1 WO2004108610A1 PCT/GB2004/001532 GB2004001532W WO2004108610A1 WO 2004108610 A1 WO2004108610 A1 WO 2004108610A1 GB 2004001532 W GB2004001532 W GB 2004001532W WO 2004108610 A1 WO2004108610 A1 WO 2004108610A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- impeller
- compressor
- motor
- turbocompressor
- diffuser
- Prior art date
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
- F04D27/02—Surge control
- F04D27/0261—Surge control by varying driving speed
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/02—Aerobic processes
- C02F3/12—Activated sludge processes
- C02F3/20—Activated sludge processes using diffusers
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/006—Regulation methods for biological treatment
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D25/00—Pumping installations or systems
- F04D25/02—Units comprising pumps and their driving means
- F04D25/08—Units comprising pumps and their driving means the working fluid being air, e.g. for ventilation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/22—O2
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Definitions
- the present invention relates to sewage aeration, and in particular to a sewage aeration system including a centrifugal air compressor.
- Water treatment plants generate large volumes of sewage sludge. It is necessary to continuously aerate tanks of sewage sludge by delivering compressed air to the sludge in appropriately designed aeration tanks.
- air compressors three different types are used, that is positive displacement blowers, single or multistage centrifugal radial flow fans, and mixed flow turbo compressors.
- Turbocompressors have not dominated the sewage aeration market for two main reasons, that is firstly high capital cost as compared to the alternatives, and secondly an inability to maintain high efficiency in applications where widely varying flow rates are demanded.
- the operators of sewage aeration plant are sensitive to both capital cost and long term operating costs and therefore monitor oxygen demand in treatment plants and reduce the volume of air supplied if a reduced oxygen demand is indicated. This means that in many applications a compressor must be able to be turned down by as much as 50%, that is to deliver anything between 50% and 100% of maximum output.
- Turbocompressors can be considered as belonging to one of two general design types, that is variable geometry and fixed geometry designs.
- variable geometry designs the geometry of passageways within the compressor can be varied as the compressor is rotating so as to adjust compressor characteristics to match varying conditions such as speed or load.
- fixed geometry design no geometry adjustments are possible during operation.
- a constant speed induction motor drive is coupled to the turbocompressor by a fixed ratio gearbox such that the turbocompressor rotates at a constant speed higher than the motor speed.
- a turbocompressor which is driven by a conventional induction motor operating at six times synchronous speed, the motor being directly coupled to the turbocompressor to avoid the need for a gear box.
- the motor is controlled by an inverter, turndown being achieved by controlling the frequency of the AC power supplied to the motor by the inverter.
- This arrangement is advantageous as gear box power losses are avoided, but at the cost of increased power losses arising in the inverter/motor combination.. These losses are substantial however and thus significant power savings cannot be readily achieved.
- stator windings are supplied from a DC source through power electronic switches of an inverter.
- the rotor supports permanent magnets.
- the stator winding switches are switched so as to be conducting at times determined by a controller which in general is responsive to inputs representing a speed command and a measurement of or estimate of rotor position. Interaction between the magnetic fields produced by the permanent magnets and the magnetic fields generated by the stator windings causes the rotor to rotate. It is known that relatively high efficiencies can be achieved with permanent magnet motors but generally such motors are only used in relatively low power applications. The use of permanent magnet motors has not been considered in sewage aeration applications where typically powers of the order of 300kW are required.
- a sewage aeration turbocompressor for continuously delivering air to a sewage sludge treatment plant, comprising a compressor having a housing, an impeller mounted on an impeller shaft within the housing, and an electric motor having an output shaft coupled to and rotating in synchronism with the impeller shaft, the housing defining an axial air inlet extending to the impeller, a diffuser passageway extending radially outwards from the impeller, and a volute extending from the diffuser to an air outlet, wherein the electric motor is a variable speed permanent magnet motor controlled by an inverter, the motor is deigned to drive the compressor at speeds within a range limited by maximum and minimum design speeds, the compressor is a fixed geometry compressor with a vaneless diffuser designed to deliver a pressure rise between the inlet and outlet of not more than 1500 millibar when the motor is driven at the maximum design speed, and the compressor is designed to deliver maximum efficiency when the motor is driven at a speed less than the maximum design speed.
- the electric motor is a variable speed
- the pressure rise ranges from 850 to 1200 millibars. Maximum efficiency may be in the range 1000 to 1050 millibars.
- the impeller design can be optimised to suit the particular application.
- the volute can be designed to optimise efficiency given the vaneless nature of the diffuser.
- no vanes are provided in the air inlet, again avoiding energy losses across at least some of the range of possible impeller rotational speeds.
- the diffuser passageway may be a simple annular passageway of uniform width in the axial direction.
- the inverter may be controlled by an oxygen demand sensor coupled so as to monitor the oxygen content of sludge in the sludge treatment plant.
- Figure 1 is a schematic block diagram illustrating components incorporated in an embodiment of the present invention
- Figure 2 is an axial section through a turbocompressor incorporated in the system illustrated in Figure 1 ;
- Figure 3 is a schematic perspective view of an impeller and volute of the turbocompressor shown in Figure 2;
- Figure 4 represents the relative efficiencies at variable flow rates of the turbocompressor shown in Figures 2 and 3 and a conventional sewage aeration turbocompressor incorporating diffuser vanes;
- Figure 5 represents the variation of isentropic efficiency with mass flow for the impellor, diffuser and impeller/diffuser combination in a turbocompressor according to the invention.
- the illustrated system comprises a turbocompressor 1 delivering a flow of air represented by line 2 to an aeration vessel 3, the delivered air being for example bubbled through sewage sludge retained in the vessel 3.
- the output pressure of the turbocompressor will be relatively low, for example 1.2 bar, with a maximum flow rate of for example 11000m 3 per hour.
- the turbocompressor 1 is driven by a permanent magnet motor 4 having an output shaft 5 which is directly coupled to an input shaft of the turbocompressor. Thus the motor 4 and turbocompressor 1 rotate in synchronism.
- An inverter 6 controls the supply of power to the motor 4, the inverter delivering a current in the range of 200 to 480 Amps to produce a useful power output of the order of up to 300kW.
- the power supplied to the motor 4 by the inverter 6 is controlled by an input 7 to the inverter provided by an oxygen demand sensor 8 which senses the oxygen demand in the vessel 3.
- the turbocompressor comprises a drive shaft 9 which is directly coupled to and rotates in synchronism with the output shaft 5 of the motor 4 (see Figure 1).
- the turbocompressor shaft 9 is mounted on suitable bearings and supports an impeller 10 having a central hub from which an array of impeller vanes extend.
- the hub is shown in Figure 2 but is not shown in Figure 3 so as to make it easier to see the shape of the impeller vanes.
- the impeller extends into a vaneless axial inlet 11 such that when the shaft is rotated the impeller 10 draws air in through that inlet and delivers pressurised air to a diffuser 12 which is in the form of an annular vaneless slot which is of uniform width in the aerial direction and which extends radially outwards from the impeller 10.
- the diffuser 12 communicates with a volute 13 which in turn is coupled to an air delivery line corresponding to the line 2 of Figure 1.
- the radially inner edge of the diffuser 12 is indicated by line 14 and the position of that edge is indicated by numeral 14 in Figure 2.
- Turbocompressors having vaneless inlets and diffusers of the general type illustrated in Figures 2 and 3 are known, as are the criteria which apply to the design of for example the impeller vanes so as to deliver a given rate of flow and output pressure for a given impeller speed.
- the use of such a turbocompressor with a permanent magnet motor to deliver air to an aeration vessel in a sewage plant is not however known.
- the use of such a turbocompressor in those circumstances does however provide substantial benefit as discussed with reference to Figure 4.
- the line 15 shows the relationship between isentropic efficiency and the percentage of maximum flow for the turbocompressor of Figures 2 and 3. It will be noted that efficiency peaks at around 70% of maximum flow at just above 85% and falls by a few percentage points at 100% of maximum flow. At all times the efficiency is well above 80%.
- the line 16 represents the relationship between isentropic efficiency and percentage maximum flow in a turbocompressor with a vaned diffuser designed to maximise efficiency in a conventional manner, that is by achieving the highest possible efficiency over a relatively narrow range of impeller speeds.
- the line 16 indicates a maximum efficiency of 87%, the efficiency falling off with increasing flow to 82% but decreasing very rapidly with decreasing flow.
- row 1 represents a direct drive, permanent magnet motor and high efficiency vaneless diffuser compressor combination in accordance with the invention
- row 2 represents a gear ox, induction motor and variable vane diffuser combination
- row 3 represents a direct drive induction motor vaneless diffuser combination
- row 4 represents a positive displacement belt driven blower
- turbocompressor systems applied to sewage aeration relied upon fixed speed motors and a gearbox, supplemented by variable vane structures
- the motor, turbocompressor and gearbox losses are such that high overall efficiencies cannot be achieved.
- the described embodiment of the present invention relies upon a high efficiency motor, and a very efficient impeller/vaneless diffuser compressor delivering a high efficiency across a wide range of compressor speeds.
- the variable speed drive motor does require an inverter for motor control, but energy losses in the inverter are relatively small, enabling an overall efficiency significantly better than any of the other alternatives, particularly if the turbocompressor is designed to deliver a relatively low pressure flow of air which is what is required in most sewage aeration applications.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP04726203A EP1633682A1 (en) | 2003-06-07 | 2004-04-07 | Combination of compressor and permanent magnet motor for sewage aeration |
CA002522123A CA2522123A1 (en) | 2003-06-07 | 2004-04-07 | Combination of compressor and permanent magnet motor for sewage aeration |
US10/559,394 US20060275114A1 (en) | 2003-06-07 | 2004-04-07 | Combination of compressor and permanent magnet motor for sewage aeration |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0313143.0 | 2003-06-07 | ||
GBGB0313143.0A GB0313143D0 (en) | 2003-06-07 | 2003-06-07 | Sewage aeration |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2004108610A1 true WO2004108610A1 (en) | 2004-12-16 |
WO2004108610A8 WO2004108610A8 (en) | 2005-12-08 |
Family
ID=9959533
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB2004/001532 WO2004108610A1 (en) | 2003-06-07 | 2004-04-07 | Combination of compressor and permanent magnet motor for sewage aeration |
Country Status (8)
Country | Link |
---|---|
US (1) | US20060275114A1 (en) |
EP (1) | EP1633682A1 (en) |
KR (1) | KR20060058057A (en) |
CN (1) | CN1802319A (en) |
CA (1) | CA2522123A1 (en) |
GB (1) | GB0313143D0 (en) |
TW (1) | TW200506172A (en) |
WO (1) | WO2004108610A1 (en) |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1571348A3 (en) * | 2004-03-05 | 2008-12-24 | AWECO APPLIANCE SYSTEMS GmbH & Co. KG | Centrifugal pump |
DE102006028913A1 (en) * | 2006-06-21 | 2007-12-27 | Aweco Appliance Systems Gmbh & Co. Kg | Pump, in particular for water-bearing household machines |
JP5297047B2 (en) * | 2008-01-18 | 2013-09-25 | 三菱重工業株式会社 | Method for setting performance characteristics of pump and method for manufacturing diffuser vane |
US20090241595A1 (en) * | 2008-03-27 | 2009-10-01 | Praxair Technology, Inc. | Distillation method and apparatus |
US7785405B2 (en) * | 2008-03-27 | 2010-08-31 | Praxair Technology, Inc. | Systems and methods for gas separation using high-speed permanent magnet motors with centrifugal compressors |
US8529665B2 (en) | 2010-05-12 | 2013-09-10 | Praxair Technology, Inc. | Systems and methods for gas separation using high-speed induction motors with centrifugal compressors |
CN102182710B (en) * | 2011-03-23 | 2013-07-17 | 清华大学 | Centrifugal compressor with asymmetrical vane-less diffusers and producing method thereof |
EP2545766B1 (en) * | 2011-07-14 | 2014-07-09 | Black & Decker Inc. | A debris blowing and/or vacuum appliance |
US8657918B2 (en) | 2011-11-17 | 2014-02-25 | Praxair Technology, Inc. | Cyclic adsorption process using centrifugal machines |
JP6055706B2 (en) * | 2013-03-28 | 2016-12-27 | 株式会社日立製作所 | Centrifugal pump |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20010018026A1 (en) * | 1999-04-19 | 2001-08-30 | Capstone Turbine Corporation | Helical flow compressor/turbine permanent magnet motor/generator |
EP1217214A2 (en) * | 2000-12-21 | 2002-06-26 | Ingersoll-Rand European Sales Limited | Compressor and driving motor assembly |
US6435167B1 (en) * | 1999-11-26 | 2002-08-20 | Daimlerchrysler Ag | Exhaust gas turbocharger |
WO2002086324A2 (en) * | 2001-04-23 | 2002-10-31 | Elliott Turbomachinery Co., Inc. | Multi-stage centrifugal compressor |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5752380A (en) * | 1996-10-16 | 1998-05-19 | Capstone Turbine Corporation | Liquid fuel pressurization and control system |
US6402941B1 (en) * | 2000-02-07 | 2002-06-11 | Wastewater Biological Solutions, Corp | Apparatus for biological treatment of environmental contaminants and waste |
US6382912B1 (en) * | 2000-10-05 | 2002-05-07 | The United States Of America As Represented By The Secretary Of The Navy | Centrifugal compressor with vaneless diffuser |
-
2003
- 2003-06-07 GB GBGB0313143.0A patent/GB0313143D0/en not_active Ceased
-
2004
- 2004-04-07 CA CA002522123A patent/CA2522123A1/en not_active Abandoned
- 2004-04-07 CN CNA200480015858XA patent/CN1802319A/en active Pending
- 2004-04-07 US US10/559,394 patent/US20060275114A1/en not_active Abandoned
- 2004-04-07 WO PCT/GB2004/001532 patent/WO2004108610A1/en not_active Application Discontinuation
- 2004-04-07 KR KR1020057023463A patent/KR20060058057A/en not_active Application Discontinuation
- 2004-04-07 EP EP04726203A patent/EP1633682A1/en not_active Withdrawn
- 2004-04-08 TW TW093109712A patent/TW200506172A/en unknown
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20010018026A1 (en) * | 1999-04-19 | 2001-08-30 | Capstone Turbine Corporation | Helical flow compressor/turbine permanent magnet motor/generator |
US6435167B1 (en) * | 1999-11-26 | 2002-08-20 | Daimlerchrysler Ag | Exhaust gas turbocharger |
EP1217214A2 (en) * | 2000-12-21 | 2002-06-26 | Ingersoll-Rand European Sales Limited | Compressor and driving motor assembly |
WO2002086324A2 (en) * | 2001-04-23 | 2002-10-31 | Elliott Turbomachinery Co., Inc. | Multi-stage centrifugal compressor |
Non-Patent Citations (1)
Title |
---|
J. APPLEBAUM ET AL.: "Aeration of Fishponds by Photovoltaic Power", PROGRESS IN PHOTOVOLTAICS. RESEARCH AND APPLICATIONS., vol. 9, no. 4, 2001, GBJOHN WILEY AND SONS, CHICHESTER., pages 295 - 301, XP002295322 * |
Also Published As
Publication number | Publication date |
---|---|
KR20060058057A (en) | 2006-05-29 |
CA2522123A1 (en) | 2004-12-16 |
GB0313143D0 (en) | 2003-07-09 |
US20060275114A1 (en) | 2006-12-07 |
EP1633682A1 (en) | 2006-03-15 |
WO2004108610A8 (en) | 2005-12-08 |
CN1802319A (en) | 2006-07-12 |
TW200506172A (en) | 2005-02-16 |
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