Gas separation: processes – Deflecting – Centrifugal force
Reexamination Certificate
1999-07-23
2001-05-01
Smith, Duane S. (Department: 1724)
Gas separation: processes
Deflecting
Centrifugal force
C055S325000, C055S442000, C055S444000, C055S447000, C055SDIG002, C095S272000, C096S055000
Reexamination Certificate
active
06224654
ABSTRACT:
BACKGROUND OF THE INVENTION
Dust particles must be removed from chimney gases of factories to improve the environment and comply with legal environmental standards. A number of methods are available for the dust collection of the outgoing gases. For example, bag filters, electrostatic precipitators (ESP) and cyclones have been used in the past. Kwasniak,
Application of the Multiwir Method to Separation of Droplets and Solid Particles from Gases
, Institute of Chemical Engineering, Technical University of Lodz, ul, Zwirki 36, 90-924 Lodz (Poland), pp 211-2151 hereby incorporated by reference has suggested the use of ‘Multiwir’ packaging to separate droplets and solid particles from gases. U.S. Pat. No. 5,813,451 for an “Apparatus for Heat Transfer from Dust Laden Gases to Fluids”, which is hereby incorporated by reference, describes the use of Multiwir packaging has been extended to remove solid particles and at the same time to recover waste heat out of dust laden gases. Multiwir, which is a type of filter consisting of a number of parallel plates, as shown in
FIG. 1
, is explained in further detail below.
In many cases the removal efficiency achieved with cyclones, ESP or in Multiwir is not sufficient to meet legal standards created for the protection of the environment. For example, if there is a large number of smaller (finer) particles present that are difficult to remove from the gases, or if the gas flow rate or the dust load has been increased substantially as compared to the amounts anticipated in the original design of the dust removal system.
It is an object of this invention to provide a substantial increase in the efficiency of dust removal, by dedusters to comply with legal standards and to benefit the environment.
SUMMARY OF THE INVENTION
It has been found that maximum dust removal can take place using a two-step process. The chimney gases are passed through two sets of Multiwirs, described below. First, the gases pass through a first Multiwir at a high rate of speed-preferably between approximately 8-14 m/s.
Second, the gases pass through a second Multiwir at a low rate of speed-preferably approximately 6.5 m/s or less.
A Multiwir is shown in FIG.
1
. The Multiwir packaging consists of multiple adjacent layers of uniformly spaced parallel plates that are inclined at an angle to the flow of gas, the angle of one layer of parallel plates being oppositely inclined from, preferably substantially complementary to, that of the next adjacent layer. The parallel plates divide the gas streams that cross each other and collide, thereby causing vortices (whirling masses) of gases to be formed by the transfer of momentum between the gas streams.
During the first step, as the gases pass through the first Multiwir, the dust particles begin to agglomerate and produce larger particles. Agglomeration is the process in which particles grow by collision with and assimilation of other particles suspended in gases. Most of these larger particles, which are the result of agglomeration, flow into the second Multiwir.
During the second step, the agglomerated particles are removed. Thus, the invention provides for a method and apparatus for removing chimney dust by agglomerating the particles as they pass through a first Multiwir at a high rate of speed preferably between approximately 8-14 m/s, then removing the agglomerated particles as they pass through a second Multiwir at a low rate of speed, preferably approximately 2-6.5 m/s.
Ultimately a method is contemplated of (1) passing a flow of chimney gases laden with dust particles, at a certain velocity through a first Multwir, where the velocity is selected both to cause agglomeration of the dust particles and suspension of agglomerated particles in the gas stream; (2) agglomerating the dust particles of the gases as they pass through the first Multiwir; (3) passing the gas stream carrying agglomerated particles at a selected second gas stream velocity through a second Multwir; (4) removing the agglomerated dust particles as they pass through the second Multiwir at the second gas stream velocity;
wherein the second gas stream velocity is substantially slower than the first gas stream velocity.
REFERENCES:
patent: 1405613 (1922-02-01), Milliken
patent: 2013644 (1935-09-01), Bubar
patent: 3389974 (1968-06-01), Baratini et al.
patent: 3785620 (1974-01-01), Huber
patent: 3813856 (1974-06-01), Jensen
patent: 4036461 (1977-07-01), Soligno
patent: 4062524 (1977-12-01), Brauner et al.
patent: 4570883 (1986-02-01), Wepfer
patent: 4637455 (1987-01-01), Tordonato
patent: 4832710 (1989-05-01), Jury
patent: 5238055 (1993-08-01), Kelley
patent: 5318609 (1994-06-01), Kittler
patent: 5500271 (1996-03-01), Pasch et al.
patent: 5536288 (1996-07-01), DeWitt et al.
patent: 5813451 (1998-09-01), Chawla
patent: 5816317 (1998-10-01), Chawla
patent: 6007593 (1999-12-01), Dullien
patent: 6051041 (2000-04-01), Wurz et al.
Kurt Leschonski, et al., “The Measurement of the Separation of Fine Solid Particles in Multiwir Packings”,Part. Part. Syst. Charact.vol. 15, pp. 274-280 (Oct. 1998).
Jan Kwasniak, “Application of the Multivir Method to Separation of Droplets and Solid Particles From Gases”,Chemical Engineering Process,vol. 24, pp. 211-215 (Sep. 1988).
J. Kwasniak, et al., Stromungsfelder, Partikelabscheidung und Druckverlust in Multiwir-Packungen,Chemical Engineering Process,pp. 1-10 (Sep. 1988).
Peter Weib, Untersuchungen am Multiwir-Tropfenabscheider, Dralluckgewinnung in Zyklontauchrohen,Studienarbeit am Institut fur Mechanische Verfahrenstechnik, pp. 1-T6 (Stuttgart 1993).
Joachim Fischer, “Partikelabscheidung in Multiwir—Packungen”, Zugl: Clausthal, Techn. Univ. Diss., Papierflieger, Clausthal-Zellerfeld, pp. 1-196 (Aug. 1996).
Chem. Eng. Process. 24 p. 211-215 ,“Application of the 'Mutlivir38 Method to Separation of Droplets and Solid Particles from Gases” by Jan Kwasniak (1988).
Jaeckle Fleischmann & Mugel LLP
Smith Duane S.
LandOfFree
Method for enhancement of duct removal out of chimney gases does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for enhancement of duct removal out of chimney gases, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for enhancement of duct removal out of chimney gases will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2523517