WO1997022400A1 - Method for separating dust from hot process gases - Google Patents
Method for separating dust from hot process gases Download PDFInfo
- Publication number
- WO1997022400A1 WO1997022400A1 PCT/SE1996/001454 SE9601454W WO9722400A1 WO 1997022400 A1 WO1997022400 A1 WO 1997022400A1 SE 9601454 W SE9601454 W SE 9601454W WO 9722400 A1 WO9722400 A1 WO 9722400A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- dust
- process gases
- mixer
- flue gases
- duct
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D51/00—Auxiliary pretreatment of gases or vapours to be cleaned
- B01D51/02—Amassing the particles, e.g. by flocculation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
- B03C3/34—Constructional details or accessories or operation thereof
- B03C3/88—Cleaning-out collected particles
-
- 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
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S55/00—Gas separation
- Y10S55/25—Agglomerators
Definitions
- the present invention relates to a method for sepa ⁇ rating dust from hot process gases, such as flue gases, in which method the process gases are conducted through a gas inlet duct to a dust separator, in which dust is separated from the process gases and from which the cleaned process gases are discharged through an outlet duct, part of the dust separated in the dust separator being passed to a device for agglomeration of the dust and then recirculated by being introduced into the pro- cess gases in the gas inlet duct.
- process gases such as flue gases
- the effi ⁇ ciency of the dust separator is increased in relation to the efficiency obtained without such recirculation.
- the object of the present invention is to provide a method for separating dust from hot process gases, said method additionally improving the efficiency of the dust separator.
- This object is achieved by a method which is of the type described by way of introduction and characterised in that liquid is supplied to the dust in the agglomerat ⁇ ing device in such an amount that the relative humidity in the cleaned process gases in the outlet duct is higher than 30%, preferably 40-60%.
- Fig. 1 is a schematic view of a plant for cleaning flue gases from a coal-fired central heating plant, the cleaning plant being provided with equipment for carrying out the method according to the invention
- Fig. 2 is a side view in which certain parts have been broken away and which shows a mixer used for carry- ing out the method according to the invention
- Fig. 3 shows a mixer according to Fig. 2 from above
- Fig. 4 is a cross-sectional view along line IV-IV in Fig. 3.
- Fig. 1 schematically shows a plant for cleaning flue gases from a coal-fired central heating plant 1, said flue gases containing dust, such as fly ash.
- a preheater 2 is arranged to transmit heat from the hot flue gases to combustion air, which is supplied through a duct 2a to the central heating plant 1 by means of a fan 3.
- the hot flue gases are passed through a duct 4 to a dust separator 5, which in the shown embodiment is a fabric filter, which in known manner comprises a plura ⁇ lity of rows of filter bags and through which the flue gases are passed to be cleaned.
- the thus cleaned flue gases are passed through a duct 6 to a flue gas blower 7, which through a duct 8 feeds them to a chimney 9 to be discharged into the atmosphere.
- the dust separator can also be, for instance, an electrostatic precipitator.
- the duct 4 comprises a vertical portion 10.
- a mixer 11 communicates with this portion 10 in the lower part thereof.
- the mixer 11 introduces in the manner that will be described in more detail below moistened and agglome ⁇ rated dust particles into the flue gases in the lower part of the duct portion 10.
- the dust particles separated in the dust separator 5 are collected in the hoppers 12 of the dust separator 5. Part of the collected dust particles is recirculated in the system by being passed to the mixer 11 (arrow Pl ) . The remainder of the collected dust particles is trans ⁇ ported away in a manner not described in detail, for instance, by means of a screw conveyor.
- the mixer 11 is a mixer of the type described in WO 96/16727 and shown in more detail in Figs 2-4.
- the mixer 11 shown in Figs 2-4 comprises a contai ⁇ ner 13, which essentially is in the shape of an elongate, parallelepipedal box.
- the container 13 has two vertical side walls 14 and 15, a vertical rear end wall 16, a ver ⁇ tical front end wall 17, a horizontal upper bottom 18, a horizontal lower bottom 19 and a horizontal top or lid 20.
- the container 13 has an inlet 21, through which dust particles from the hoppers 12 are supplied from above into the container 13 (arrow Pl in Figs 1 and 2), and at its front end, an outlet 22, through which a homogeneous mixture of agglomerated dust particles and water is discharged (arrows P2 in Figs 3 and 4 ) .
- the front end of the container 13 is inserted in the vertical duct por ⁇ tion 10, through which the flue gases are conducted up- wards (arrows P3 in Figs 1, 2 and 4).
- the outlet 22 is an overflow formed as a result of the side walls 14 and 15 being lower in the part of the container 13 inserted in the duct portion 10 than in the container part located outside the duct portion 10.
- the top 20 extends from the inlet 21 to the outlet 22, i.e. up to the duct portion 10.
- the two bottoms 18 and 19 define a chamber 23 which, in the lateral direction, is delimited by the two side walls 14 and 15 and, in the longitudinal direction, is delimited by the two end walls 16 and 17.
- the ceiling of the chamber 23, i.e. the upper bottom 18, consists of an air-permeable fluidisation cloth of poly ⁇ ester mounted in stretched state in the container 13.
- An air-supply means, which in the embodiment shown consists of two air inlets 24 and 25, is arranged to supply air to the chamber 23 ( arrows P4 in Figs 2 and 3 ) , so as to fluidise the dust particles in the container 13.
- a water-supply line 26, which disposed above the container 13 is connected to a plurality of nozzles 27 arranged in the upper part of the container 13 to spray water in finely-divided form over the dust particles in the container.
- the nozzles 27, of which but a few are shown in the drawings, are arranged in two parallel rows extending along the container 13.
- Two juxtaposed horizontal shafts 28, 28' extend along the entire container 13 and are rotatably mounted in the two end walls 16 and 17 with the aid of bearings 29, 29' and 30, 30', respectively.
- a motor 31 is arranged to rotate the shafts 28, 28' via a transmission unit 32.
- Each shaft 28, 28' supports a plurality of elliptic discs 33, 33', which, about their minor axes, are mounted in inclined state on the shafts 28, 28' at an axial dis ⁇ tance from one another.
- the shafts 28, 28' extend through the centres of the respective discs 33, 33' .
- each disc 33, 33' is so inclined in re ⁇ lation to the shaft 28, 28' that the angle ⁇ between the major axis of the disc and the shaft 28, 28' is about 60° (see Fig. 2). This angle ⁇ may vary between 45° and 80°.
- the discs 33, 33' are so inclined in relation to the respective shafts 28, 28' and have such an elliptic shape as to have a circular axial projection, as illustrated in Fig. 4.
- the discs 33, 33' are so positioned on the respective shafts 28, 28' that the discs of the one shaft project into the spaces between the discs of the other shaft.
- Each of the discs 33, 33' arranged and designed in the manner indicated above performs, during the rotation of the shafts 28, 28', a throwing movement conducive to thorough mixing of the dust particles.
- a partition 34 in the front part of the container 13 the chamber 23 is divided into a front part chamber 23a, which is situated in the duct portion 10, and a rear part chamber 23b.
- the air inlet 24 opens into the rear part chamber 23b, while the air inlet 25 opens into the front part chamber 23a.
- the mixer 11 By the design of the mechanical mixing mechanism and by fluidisation of the dust particles supplied to the mixer, the mixer 11 produces a homogeneously moistened, homogeneous mixture of dust particles which is, via the overflow 22 of the mixer 11, continuously introduced into the duct portion 10 as agglomerated dust particles.
- the flow rate of the flue gases was 45,000 Nm-3/h.
- the flue gases had a dust content of 19.3 g/Nrn ⁇ and a temperature of 130°C.
- the differential pressure over the fabric filter 5, which comprised 20 rows of filter bags, was constantly kept at 2,000 Pa by cleaning each row of filter bags by means of a strong compressed-air pulse, an entire cycle for clean ⁇ ing all the rows of filter bags of the filter being pass- ed in about 30 s. The interval between the pulses thus was about 1.5 s.
- separated dust par ⁇ ticles were recirculated in an amount of about 60 t/h.
- the recirculated dust particles had an average particle size of 26 ⁇ m.
- the dust content of the flue gases at B in the duct 6 was measured to be 35 mg/Nm ⁇ .
- the flow rate of the flue gases was 45,000 Nm ⁇ /h.
- the flue gases had a dust content of 20.5 g/Nm-3 and a temperature of 130°C.
- the differential pressure over the fabric filter 5, which comprised 20 rows of filter bags, was constantly kept at 2,000 Pa by cleaning each row of filter bags by means of a strong compressed-air pulse, an entire cycle for clean ⁇ ing all rows of filter bags of the filter being passed in about 16 min. The interval between the pulses thus was about 48 s.
- separated dust particles were recirculated in an amount of about 60 t/h.
- the recirculated dust particles had an average particle size of 33 ⁇ m.
- the flow rate of the flue gases was 45,000 Nm ⁇ /h.
- the flue gases had a dust content of 20.2 g/Nm ⁇ and a temperature of 130°C.
- the differential pressure over the fabric filter 5, which comprised 20 rows of filter bags, was constantly kept at 2,000 Pa by cleaning each row of filter bags by means of a strong compressed-air pulse, an entire cycle for clean ⁇ ing all rows of filter bags of the filter being passed in about 28 min. Thus, the interval between the pulses was about 84 s.
- separated dust particles were recirculated in an amount of about 60 t/h.
- the re ⁇ circulated dust particles had an average particle size of 40 ⁇ m. Water was supplied to the mixer 11 in an amount of about 1.4 m- ⁇ /h, thereby cooling the flue gases to about
- the dust content of the flue gases at B in the duct 6 was measured to be 8.8 mg/Nm ⁇ .
- Experiment 5 Like in Experiments 1, 2, 3 and 4, the flow rate of the flue gases was 45,000 Nm ⁇ /h. At A, the flue gases had a dust content of 18.5 g/Nm ⁇ and a temperature of 130°C.
- the differential pressure over the fabric filter 5, which comprised 20 rows of filter bags, was constantly kept at 2,000 Pa by cleaning each row of filter bags by means of a strong compressed-air pulse, an entire cycle for clean ⁇ ing all rows of filter bags of the filter being passed in about 62 min. Thus, the interval between the pulses was about 186 s.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Filtering Of Dispersed Particles In Gases (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Treating Waste Gases (AREA)
- Cyclones (AREA)
Abstract
Description
Claims
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE69620795T DE69620795T2 (en) | 1995-12-20 | 1996-11-12 | METHOD FOR SEPARATING DUST FROM HOT PRODUCTION GASES |
AU75938/96A AU7593896A (en) | 1995-12-20 | 1996-11-12 | Method for separating dust from hot process gases |
AT96938601T ATE216279T1 (en) | 1995-12-20 | 1996-11-12 | METHOD FOR SEPARATING DUST FROM HOT MANUFACTURING GASES |
EP96938601A EP0876191B1 (en) | 1995-12-20 | 1996-11-12 | Method for separating dust from hot process gases |
DK96938601T DK0876191T3 (en) | 1995-12-20 | 1996-11-12 | Process for separating matter from hot process gases |
US09/100,099 US6051054A (en) | 1995-12-20 | 1998-06-19 | Method for separating dust from hot process gases |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9504557-1 | 1995-12-20 | ||
SE9504557A SE505579C2 (en) | 1995-12-20 | 1995-12-20 | Ways to separate dust from hot process gases |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/100,099 Continuation US6051054A (en) | 1995-12-20 | 1998-06-19 | Method for separating dust from hot process gases |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1997022400A1 true WO1997022400A1 (en) | 1997-06-26 |
Family
ID=20400649
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE1996/001454 WO1997022400A1 (en) | 1995-12-20 | 1996-11-12 | Method for separating dust from hot process gases |
Country Status (11)
Country | Link |
---|---|
US (1) | US6051054A (en) |
EP (1) | EP0876191B1 (en) |
AT (1) | ATE216279T1 (en) |
AU (1) | AU7593896A (en) |
DE (1) | DE69620795T2 (en) |
DK (1) | DK0876191T3 (en) |
ES (1) | ES2175144T3 (en) |
SE (1) | SE505579C2 (en) |
TR (1) | TR199601029A1 (en) |
WO (1) | WO1997022400A1 (en) |
ZA (1) | ZA9610152B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7766997B2 (en) | 2007-12-21 | 2010-08-03 | Alstom Technology Ltd | Method of reducing an amount of mercury in a flue gas |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE512227C2 (en) * | 1998-06-24 | 2000-02-14 | Flaekt Ab | Ways to clean flue gases during the start-up of a boiler |
US20040106366A1 (en) * | 2002-08-26 | 2004-06-03 | Robinson Robert A. | Portable pipe restoration system |
US20060037293A1 (en) * | 2004-08-17 | 2006-02-23 | Storer Ron D | Blast medium pot |
US7008304B1 (en) * | 2004-08-17 | 2006-03-07 | Media Blast & Abrasives, Inc. | Abrasive and dust separator |
US20070202781A1 (en) * | 2006-02-28 | 2007-08-30 | Media Blast & Abrasives, Inc. | Blast media nozzle and nozzle assembly |
US9623539B2 (en) | 2014-07-07 | 2017-04-18 | Media Blast & Abrasive, Inc. | Carving cabinet having protective carving barrier |
US20190201828A1 (en) | 2017-12-29 | 2019-07-04 | Media Blast & Abrasive, Inc. | Adjustable abrasive & dust separator |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3834123A (en) * | 1971-03-18 | 1974-09-10 | A Margraf | Dust and like filters method |
DE3639824A1 (en) * | 1986-10-22 | 1988-05-05 | Margraf Adolf | FILTERING SEPARATOR FOR PARTICLES AND POLLUTANT GAS FROM RAW GASES |
DE3925818C2 (en) * | 1989-08-04 | 1993-06-09 | Intensiv-Filter Gmbh & Co Kg, 5620 Velbert, De | |
DE19515352A1 (en) * | 1994-05-04 | 1995-11-09 | Volkswagen Ag | Agglomerator to clean diesel exhaust and other waste gases |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1445810A (en) * | 1973-09-07 | 1976-08-11 | Berz W | Apparatus for separating dust from a dust-containing gas |
US4205931A (en) * | 1978-12-04 | 1980-06-03 | Combustion Engineering, Inc. | Pneumatic ash transporting and containing system |
US4378976A (en) * | 1981-08-14 | 1983-04-05 | Institute Of Gas Technology | Combined sonic agglomerator/cross flow filtration apparatus and process for solid particle and/or liquid droplet removal from gas streams |
US4874402A (en) * | 1981-12-01 | 1989-10-17 | Shell Oil Company | Process for purifying and cooling a hot gas |
US4579567A (en) * | 1984-09-18 | 1986-04-01 | Phillips Petroleum Company | Agglomerating carbon black using cyclone at entrance to bag filter |
US4865629A (en) * | 1988-07-05 | 1989-09-12 | Industrial Filter & Pump Mfg. Co. | Control of particle size distribution in gas filtration |
US5505766A (en) * | 1994-07-12 | 1996-04-09 | Electric Power Research, Inc. | Method for removing pollutants from a combustor flue gas and system for same |
TW279242B (en) * | 1994-11-29 | 1996-06-21 | Asahi Denka Kogyo Kk | The wasted-gas processing method & device for CVD apparatus |
-
1995
- 1995-12-20 SE SE9504557A patent/SE505579C2/en not_active IP Right Cessation
-
1996
- 1996-11-12 WO PCT/SE1996/001454 patent/WO1997022400A1/en active IP Right Grant
- 1996-11-12 ES ES96938601T patent/ES2175144T3/en not_active Expired - Lifetime
- 1996-11-12 AU AU75938/96A patent/AU7593896A/en not_active Abandoned
- 1996-11-12 DK DK96938601T patent/DK0876191T3/en active
- 1996-11-12 EP EP96938601A patent/EP0876191B1/en not_active Expired - Lifetime
- 1996-11-12 DE DE69620795T patent/DE69620795T2/en not_active Expired - Lifetime
- 1996-11-12 AT AT96938601T patent/ATE216279T1/en active
- 1996-12-03 ZA ZA9610152A patent/ZA9610152B/en unknown
- 1996-12-19 TR TR96/01029A patent/TR199601029A1/en unknown
-
1998
- 1998-06-19 US US09/100,099 patent/US6051054A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3834123A (en) * | 1971-03-18 | 1974-09-10 | A Margraf | Dust and like filters method |
DE3639824A1 (en) * | 1986-10-22 | 1988-05-05 | Margraf Adolf | FILTERING SEPARATOR FOR PARTICLES AND POLLUTANT GAS FROM RAW GASES |
DE3925818C2 (en) * | 1989-08-04 | 1993-06-09 | Intensiv-Filter Gmbh & Co Kg, 5620 Velbert, De | |
DE19515352A1 (en) * | 1994-05-04 | 1995-11-09 | Volkswagen Ag | Agglomerator to clean diesel exhaust and other waste gases |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7766997B2 (en) | 2007-12-21 | 2010-08-03 | Alstom Technology Ltd | Method of reducing an amount of mercury in a flue gas |
US8277545B2 (en) | 2007-12-21 | 2012-10-02 | Alstom Technology Ltd | Method of reducing an amount of mercury in a flue gas |
Also Published As
Publication number | Publication date |
---|---|
US6051054A (en) | 2000-04-18 |
ES2175144T3 (en) | 2002-11-16 |
ATE216279T1 (en) | 2002-05-15 |
SE505579C2 (en) | 1997-09-15 |
DK0876191T3 (en) | 2002-07-01 |
EP0876191A1 (en) | 1998-11-11 |
SE9504557D0 (en) | 1995-12-20 |
DE69620795T2 (en) | 2002-10-17 |
EP0876191B1 (en) | 2002-04-17 |
DE69620795D1 (en) | 2002-05-23 |
SE9504557L (en) | 1997-06-21 |
TR199601029A1 (en) | 1997-07-21 |
ZA9610152B (en) | 1997-06-18 |
AU7593896A (en) | 1997-07-14 |
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