Everything Depends on Pressure And Maintenance ENERGY AND COST EFFICIENCY OF BIOLOGICAL TREATMENT PLANTS Every biologically working sewage plant needs a compressed air station for the oxygen supply of the aeration basin. This station only works at the highest possible energy efficiency level if excessive plant pressure through the subordinated system, excessive intake temperatures due to insufficient aeration and deaeration, and increased operating hours due to insufficient maintenance, are excluded. The following examples show that these criteria can have a positive or negative effect on the energy balance of a blower. INCREASED PLANT PRESSURETreatment plant maintenancePrior to delivery, each blower is set to a predefined pressure. The air compressed to this pressure is mostly channelled via a closed circular pipe with several stubs to the airstones installed in the basin. Incorrectly triggered diaphragm control valves at the entry of the basin can lead to in- creased pressure in the supply system. Then the compressors have to run against this pressure, which leads to higher energy expenditure and thus to extra costs. Another criterion: the slide valves are triggered via maintaining a constant pressure. The sup- ply pipes are closed automatically as soon as the required oxygen content in the basin has been achieved. Frequency controlled blowers are shut down with a certain delay. In case of a too lengthy delay, first of all the blowers continue running at full load against the closed, or partly closed, slide valves. Air has to escape via the pressure valves, which may lead to air losses and in the worst case scenario to damage of the blower stages.The back pressure can also increase when the airstones in the basin become aged due to the presence of chemical components in the waste water, or the pipings and/or airstones get clogged up over time, for example with detached adsorption material from the blower silencers. For Aerzen positive displacement blowers built since 1995, as well as Aerzen rotary lobe compressors of the new Delta Hybrid series, this risk does not exist. Here, the base support is formed as a pulsation silencer, with noise reduction achieved by means of air deflections instead of via adsorption material. Examples show that a pressure increase of 50 mbar may result in additional energy expenditure, depending on blower design, of between 5 and 10 per cent, and consequently in extra costs potentially amounting to several thousand Euros.INCREASED INTAKE TEMPERATUREExcessive plant pressure or insufficient maintenance can have a negative effect on the energy balance of a positive displacement blower and consequently of a sewage plant.As the air for compression and cooling of a blower comes mostly from the installation room, the room temperature also has an influence on the energy balance of the plant. When there is an increase in the room temperature in the installation room the temperature of the air to be compressed also increases. This not only leads to an increased temperature of the compressed air and consequently to a reduced oxygen volume in the compressed air, but also to a lower degree of filling and to inferior cooling of the compressors. The consequence is that: the compressor will take longer to convey the required oxygen volume. Excessive room temperature can occur in the following situations: (1) if the aeration and deaeration orifices are incorrectly positioned or are too small; (2) if the air- flow is not supported by thermostatically- controlled fans or if their capacity is insufficient; (3) if the roof of the compressor room is insufficiently protected against solar radiation; (4) if the compressed air pipes inside the station are not isolated or else are insufficiently isolated.MAINTENANCEThe energy balance can also be negatively influenced if maintenance is not carried out according to manufacturer’s instructions. A classic example of this is a pressure valve damaged by increased resistance, caused by the above mentioned criteria, or an air filter which was replaced too late. If, just to save 50 Euros, this air filter is not replaced, but is only disassembled and blown out insufficiently and then reinstalled, the energy consumption of the blower will already increase. A standard value: a reduction of the pressure on the suction side by 10 mbar will reduce energy costs by approximately 1 per cent. A new filter will show a pressure loss of only around 5 mbar, but contaminated filters can show a pressure loss of more than 30 mbar. As compressed air stations usually consist of several compressors the extra energy costs can add up quickly. This can be avoided by maintaining all blowers in accordance with instructions, through the service divisions of the manufacturer and/ or the operator. After all, the energy costs of a compressor over its service life amount to up to 90 per cent of the total costs of the plant. Only around 10 per cent are attributable to investment and maintenance costs.
Aerzen U.S.A. selected as the “Coolest Building” In March, Key Stone Edge Magazine selected the Aerzen U.S.A. building in Coatesville as one of the five “coolest” buildings in Pennsylvania.In 2009, the “green” building of our American subsidiary which they had moved into in 2008,was awarded LEED Gold (Leadership in Energy and Environmental Design) for its sustainability by the U.S. Green Building Council. Now they have received another award from a weekly online magazine in Pennsylvania. A decisive factor for the jury was the materials used in the building’s construction, i.e. straw bales and loam, which are reasonably priced but provide good insulation. Our American headquarters is the first commercial building in Pennsylvania with straw walls.
Aerzen Sales Office in Norway Since January, Aerzener Maschinenfabrik has had its own sales office in Norway. The office, headed by Ove Fauskanger, is located in Drammen, in the southwest of Oslo, and is thus close to several big chemical companies such as Ineos, Hydro and Borealis. Besides the chemical industry, the offshore industry - or more precisely “fish farming” -plays a major role in Norway. Salmon is the country’s second most exported product. Aerzen blowers are used for example in the pneumatic conveying of feed pellets.
Aerzen Turbo strengthens Customer Support Since April of this year the arrival of Steffen Helmert has strength- ened the Aerzen Turbo-Team in its Technical Support and Customer Service area. Due to his previous roles at the subsidiary RKR he has many years of professional experience and special expertise in the Turbo Blowers range.
New CNC-external Cylindrical Grinding Machine The production facility in Aerzen deployed a new CNC-external cylindrical grinding machine, made by Messrs. Danobat, at the beginning of the year. It is equipped with three CNC-main axes (X, Z, B) as well as further axes for the workpiece drive, and an “in-process measuring system” through which it is possible to grind to micrometre accuracy. The control of the machine, Siemens 840 D Solution Line, was supplemented by a special Danobat user interface. Danobat, located in the north of Spain, near Bilbao, is part of the Danobat Group, and also demonstrates its considerable skill in innovation, in other technologies.
Aerzen Canada celebrates 25 Years The Canadian Aerzen subsidiary Aerzen Canada Inc., located in Vaudreuil near Montréal, will celebrate its 25th anniversary this year. The company, which was founded in 1987, has developed over the years from a sales office with three employees to a country-wide networked sales company which also has facilities for assembly and repair.
Delta Screw G5-series expands In April, at this year’s COMVAC in Hanover and at the POWTECH in Nuremberg, Aerzener Maschinenfabrik successfully introduced the new “E-class” directly-coupled compressors series Delta Screw G5. The new, highly energy efficient concept met with a positive response from customers and potential buyers. With the new series, Aerzener Maschinenfabrik sets new benchmarks as far as reliability and energy- saving is concerned in oil-free screw compressors. From Summer 2013 the first two compressor types, VM 45 G5-E and VML 60 G5-E, can be ordered from Aerzen. By the end of this year, two more models, the VM 75 G5-E and the VML 95 G5-E, will join the new Aerzen “E-class”. A flyer which describes the innovations, including all of their technical details, can be obtained from the Marketing division.
Aerzen Representation in Nigeria Due to the increasing number of customers in West Africa, Airgas Compressors, the South African subsidiary company of Aerzener Maschinenfabrik based in Johannesburg, decided to establish a sales office in Nigeria. The location they have selected is Lagos, the country’s biggest city, which, due to its central position, offers access not only to Nigeria but also to all of West Africa, and consequently provides considerable proximity to our customers in this region.The new office will be headed by Emmanuel Dazi. After having completed a Bachelor’s Degree in Mechanical Engineering in Nigeria, and a Master’s Degree in Mechanical Engineering at the Brunel University in London, he gained a number of year’s experience in the cement industry, where he was responsible for technical support for blowers and compressors.
Nomination for Innovation Award 2013 Aerzen Delta Real Time Monitoring was nominated for this year’s Innovation Award at the PowTech fair. Ultimately we did not win the award, but just being nominated is quite an achievement in itself, particularly as: The Aerzen product finished in the top three out of 52 competitors. In addition, Delta Real Time Monitoring had been placed, for lack of a suitable alternative, in an inapplicable category, namely MSR and automation. In 2012 Aerzener Maschinenfabrik was able to win the Innovation Award with Delta Hybrid in the apparatus construction and process components category.
