Investigation of an active noise control system to reduce the noise emitted by an industrial stack

A precise analysis of the noise emitted by an aluminum plant has shown that one of the main sources of noise is the noise emitted by an exhaust stack 40 m high and 1.8 m diametre, emitting a pure tone at 320 Hz. Because a classical cost effective solution is not available for this source, active noise control (ANC) solution was investigated.
Commonly available ANC systems, however, are not applicable to the chimney considered because the diameter of the stack (f) is too important compared to the wave length (?) of the frequency to control. In fact, until now, active noise control (ANC) has been successfully used to reduce the acoustical energy emitted at the end of ducts in the case of plane wave propagation, i.e. ?/f ?/1.7, high order modes propagate in the duct and a single canal active noise
control system is not sufficient.
This paper presents an ANC system developed to control higher modes in a circular duct. The controller used is based on a multiple-input, multiple-output adaptive filtered X-LMS and allows up to 11 error microphones and controls sources. The system has been used in a laboratory on a finite duct of 3.5 m long and 0.30 m diameter which corresponds to the same ratio ?/f for the real stack. The efficiency of the system with different numbers and location of control sources and errors sensors has been analyzed. Noise reduction of 15 dB(A) could be obtained with some configurations. Actually, the system is being considered for installation on the real chimney stack.
Full Access to Technical Paper
PDF version for $20.00
Search
Sort By:  Relevance
Showing results 1 - 8
Text
Summary: Economics of wear in mining industry and methods by which wear cost may be reduced will be discussed.
Publication: CIM Bulletin
Author(s): V.S. Sastri, M. Elboujdaini
Issue: 1012
Volume: 90
Year: 1997
Text
Summary: Laboratory wear tests are important tools that can be used for the evaluation of materials for wear applications and mitigation of wear problems in the mining industry. However, laboratory test parameters must be fully characterized and test results must be carefully interpreted if a material selection is to be made. Failure to do so may lead to erroneous conclusions. Suitable laboratory tests are valid only if they reflect the field conditions to which materials are subjected. Therefore, it...
Publication: CIM Bulletin
Author(s): W. Pascheto, N. Behnood
Issue: 1012
Volume: 90
Year: 1997
Text
Summary: Recently, lining life of the INMETCO submerged arc furnace has been dramatically extended from an average of eleven months in the 1980s to a current record of 34 months.
This paper summarizes test work and operating results describing the development and establishment
of slag parameters that reduce corrosion of the magnesite-chrome refractory lining. The desired slag parameters are now maintained by utilizing waste streams as slag additives. This paper also discusses the successful evaluation...
Publication: CIM Bulletin
Author(s): D.M. Hoffman, R.H. Hanewald, W.J. Koshut, C. Doyle, J. Hrepic, C. Díaz
Issue: 1012
Volume: 90
Year: 1997
Text
Summary: Mining along with subsequent processing of the minerals often presents conditions where a wear- and/or corrosion-resistant alloy is needed to minimize downtime and maximize efficiency. This paper is intended to give an overview of the alloys that are currently being used, as well as those developed in recent years that could be used in the mining industry. Emphasis will be put on the iron-, nickel-, cobalt-based alloys and composites containing a variety of carbides. The characteristics,...
Publication: CIM Bulletin
Author(s): B. McKee, J.B.C. Wu
Issue: 1012
Volume: 90
Year: 1997
Text
Summary: Fine tailings produced in the milling process have traditionally been disposed of in tailings ponds. Attempts have been made to use these fine tailings in backfill, however, to date the majority of backfill operations have utilized only a small percentage of fines. The
remaining fines are, therefore, being sent to tailings ponds creating a waste disposal and environmental problem. This disposal practice is even more acute in the gold milling industry where fine grinding, required for value...
Publication: CIM Bulletin
Author(s): L.M. Amaratunga, G.G. Hein, D.N. Yaschyshyn
Issue: 1012
Volume: 90
Year: 1997
Text
Summary: In 1991/1992, INCO undertook a successful R&D program aimed at extending the lining lives of the top blown rotary converters (TBRCs) at its Copper Cliff Nickel Refinery (CCNR) and the electric furnace at INMETCO. At the laboratory scale, this effort was divided into three phases. In the first part, mineralogical work was performed on six refractories that were either currently being used to line these vessels or were considered suitable alternatives. In the second part, this mineralogical...
Publication: CIM Bulletin
Author(s): C. Doyle, K. Cushnie, C. Díaz, J. Hrepic, J. Brennan
Issue: 1012
Volume: 90
Year: 1997
Text
Summary: Wear damage is responsible for very high maintenance costs and significant production losses in the oil sands industry of northern Alberta. It affects all areas of operations and involves a panoply of wear mechanisms from low stress sliding abrasion at extremely frigid temperatures during winter mining, to elevated temperature erosion/corrosion in processes where bitumen is converted to lighter hydrocarbon products.
There is no universal panacea to defend against such diverse attack and a...
Publication: CIM Bulletin
Author(s): R. Llewellyn
Issue: 1012
Volume: 90
Year: 1997
Text
Summary: Mineral exploration assessment file information has long been considered a useful resource for developing mineral exploration strategies, and one of the most common data sets filed in assessment reports is ground magnetic surveys. The new Earth Resources and Land Information System database (ERLIS) now provides a method for rapidly accessing all references to a specific area through a series of raster images. The ERLIS provides access to the Assessment File Research Imaging (AFRI) database...
Publication: CIM Bulletin
Author(s): S. Manning, W. Morris
Issue: 1012
Volume: 90
Year: 1997
Powered by Coveo Enterprise Search