WO2002072312A1 - Procede de traitement par projection de matiere - Google Patents

Procede de traitement par projection de matiere Download PDF

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Publication number
WO2002072312A1
WO2002072312A1 PCT/EP2002/002338 EP0202338W WO02072312A1 WO 2002072312 A1 WO2002072312 A1 WO 2002072312A1 EP 0202338 W EP0202338 W EP 0202338W WO 02072312 A1 WO02072312 A1 WO 02072312A1
Authority
WO
WIPO (PCT)
Prior art keywords
coatings
blasting
materials
irradiated
dry ice
Prior art date
Application number
PCT/EP2002/002338
Other languages
German (de)
English (en)
Inventor
Michael Heisel
Alexander Buinger
Original Assignee
Linde Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Linde Aktiengesellschaft filed Critical Linde Aktiengesellschaft
Priority to DE50200964T priority Critical patent/DE50200964D1/de
Priority to AT02735115T priority patent/ATE275462T1/de
Priority to EP02735115A priority patent/EP1368158B1/fr
Publication of WO2002072312A1 publication Critical patent/WO2002072312A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
    • B24C1/08—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods for polishing surfaces, e.g. smoothing a surface by making use of liquid-borne abrasives
    • B24C1/086—Descaling; Removing coating films
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
    • B24C1/003—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods using material which dissolves or changes phase after the treatment, e.g. ice, CO2

Definitions

  • the invention relates to a method for blasting objects with blasting media, the blasting media being blasted onto the object to be processed with the aid of a gas stream.
  • the blasting of objects as a treatment method with blasting media is known in numerous industrial applications.
  • the known blasting treatment methods can be divided into two groups with regard to the blasting media used.
  • the first group relates to blasting with conventional blasting media such as quartz sand in particular (sandblasting), but also with other conventional blasting media such as steel gravel, hard cast gravel, wire grain and corundum.
  • conventional blasting media such as quartz sand in particular (sandblasting)
  • other conventional blasting media such as steel gravel, hard cast gravel, wire grain and corundum.
  • Other inorganic or organic blasting agents or blasting agents based on plants can also be used as blasting media for dry abrasive blasting treatment. All these conventional abrasives have the common property that the abrasives are in a solid state under normal conditions. They are usually abrasive. Blasting treatment using conventional, abrasive blasting media results in a mixture of blasted material and blasting media, which usually has to be disposed of with great effort and high costs.
  • a second group of abrasives is known for blasting treatments which are in gaseous or liquid state under normal conditions.
  • solid carbon dioxide (CO 2 ) is used in the form of compressed, usually rice grain-sized granules.
  • CO 2 pellets are metered into a gas stream in a blasting system, conveyed with the gas stream to a blasting nozzle and passed through the blasting nozzle onto the surface to be processed.
  • the blasting nozzle is usually installed in a blasting gun.
  • Most dry ice pellets are made in a pelletizer.
  • liquid carbon dioxide is injected into the pelletizer, transferred to dry ice (snow) by expansion, compressed into a "cake” and finally pressed through a die.
  • the result is approximately rice grain-sized CO 2 pellets with a certain size distribution.
  • the granules produced in this way typically have mean values of a length of 8 mm and a diameter of 3 mm.
  • the hardness of dry ice roughly corresponds to the low hardness of gypsum.
  • the invention is based on the object of demonstrating a method of the type mentioned at the outset which brings about an improvement in the blasting treatment of surfaces.
  • This object is achieved in that at least dry ice is used as the blasting agent and an object is irradiated which comprises a carrier material with materials or coatings, the materials or coatings having a greater hardness than dry ice and a lower thermal conductivity than the carrier material.
  • an effective blasting treatment of surfaces - in particular an effective cleaning of surfaces - with the help of dry ice, i.e. by means of blasting media in fluid form under normal conditions, even if accumulations, deposits, buildup, deposits or coatings made of materials with a greater hardness than dry ice are processed.
  • object surfaces on or on which material adheres or which are coated with material which has a greater hardness than the blasting media present under normal conditions can be effectively subjected to a blasting treatment using carbon dioxide as at least one blasting agent. Because of the comparatively low hardness of the dry ice particles, it has previously been assumed that they are not suitable for blast treatment of harder materials.
  • Dry ice has a very low temperature of around -78 ° C.
  • the low temperature means a high temperature difference ⁇ T to the material to be removed.
  • the high flow velocity (preferably 100 to 300 m / s) of the carrier gas leads to high turbulence and thus high heat transfer coefficients ⁇ .
  • High heat transfer coefficients and a large temperature difference ⁇ T mean very quick, superficial cooling.
  • material that is bad Thermal conductivity as is the case with sulfur, for example, leads to high temperature gradients within the contamination layer. These in turn lead to high thermal voltages that are not reduced by heat conduction. As a result, structural changes occur in the material, which is embrittled by the low temperature, which result in weakening of the material up to cracks.
  • the blasting treatment is advantageously carried out with CO 2 pellets.
  • the dry ice or the CO 2 pellets hit the materials, coverings and / or coatings to be removed at high speed.
  • the abrasion which would require particularly hard blasting material for hard coverings, is only of minor importance as an effect in the blasting treatment.
  • the thermal conductivity of the materials or coatings has a value less than 20 W / m ° K, preferably less than 15 W / m ° K, particularly preferably less than 9 W / m ° K.
  • the thermal conductivity of the carrier material of the object is preferably greater than 30 W / m ° K greater than 35 W / m ° K, particularly preferably greater than 45 W / m ° K.
  • the carrier material is often steel, which has a thermal conductivity of approx.
  • the flow velocities of the carrier gas stream in the working area at the nozzle are from 50 m / s to 400 m / s, preferably from 100 to 350 m / s, particularly preferably from 200 to 300 m / s.
  • CO 2 penetrates into the cracks described above in the state of the transient liquid phase at high pressure. Afterwards, however, there is a sudden pressure relief because the impact energy of the CO 2 pellet does not reach down to the depth of the crack.
  • the pressure relief can have two consequences: a) The liquid relaxes and evaporates suddenly with an increase in volume by about a factor of 500 to 600. This creates a local explosive effect, the
  • the gas stream for conveying the dry ice or the CO 2 pellets can be composed of any suitable gas or gas mixture.
  • compressed air is used to supply the blasting system, for example at a pressure of 5 to 20 bar, with a dew point of 5 ° C or drier.
  • the dry ice particles or the CO 2 pellets are metered into the air stream, conveyed through the jet nozzle with the aid of the air stream, accelerated to a speed of up to 400 m / s and directed onto the surface to be cleaned.
  • the materials or coatings to be treated at least partially have a coefficient of thermal expansion different from that of the object surface.
  • the method according to the invention loses its effectiveness in the case of very thin layers of a solid. With such thin layers, poor heat conduction through the material to be removed to the underlying surface is still so good due to the small thickness that, despite poor thermal conductivity, there is only a small temperature difference between the material and the surface. This also creates only low shear forces.
  • the thin layer is only mechanically resilient, so that it adapts to the movements of the surface without becoming detached.
  • blasting media which are present can also be used under normal conditions in a solid state. Under certain circumstances, there may be advantages that outweigh or exceed the disadvantage of blasting media processing or disposal.
  • organic materials or coatings and / or sulfur-containing materials or coatings can be irradiated.
  • Parts of the system such as sulfur condensers from Claus systems, form
  • Sulfur, salts and catalyst abrasion from upstream reactors Deposits called "Sulfurcrete”. Sulfurcrete is described, for example, in the publication: H.G. Paskall, J.A. Sames: “Sulfur Recovery”, Calgary (Canada), 1989, mentioned in the chapter “Sulfur condenser function and problem areas”.
  • Sulfurcrete is a solid with a hardness similar to that of granite. Such coverings have been removed with the help of drills or similar mechanical devices. Damage to the apparatus and object surfaces due to this mechanical cleaning cannot be completely avoided and lead to a short service life of the apparatus, for example the sulfur capacitors mentioned. It It has been shown that Sulfurcrete coverings can be removed effectively using the method according to the invention. With corresponding tests on Sulfurcrete coverings, it was confirmed that blasting with dry ice particles, despite their low hardness, means that the coverings made of harder material can be separated from the surface of the object. This unexpected fact is probably due to the above-mentioned special properties of carbon dioxide and the lower thermal conductivity of Sulfurcrete compared to the carrier material, i.e. mostly steel. Specifically, the thermal conductivities of steel are approx. 46 W / m ° K, of Sulfurcrete approx. 0.5 to 1 W / m ° K.
  • the invention has proven itself particularly in the removal of soot or coke-containing materials or coatings from objects.
  • the cleaning of canned pipes, quench coolers and similar plant components that are used in the thermal cracking of hydrocarbons should be mentioned in particular. This is to be illustrated in the following using the example of cleaning quench coolers in cracking furnaces in ethylene plants.
  • coke is deposited on a wide variety of plant parts and apparatus, for example in the cracked tubes, but also in quench coolers.
  • the coke deposits narrow the free cross section of the gas flow.
  • the coke deposits also act as thermal insulation in the externally heated reaction tubes. This means that the system parts have to be decoked at regular intervals.
  • the stoves and coolers must therefore be cleaned mechanically every three to four months when they have cooled down.
  • high-pressure water of up to 2500 bar is used for cleaning, with which the deposits are removed from the tube walls.
  • this treatment leads to a sufficiently good cleaning, it leaves damage on the treated surfaces, often shell-shaped washouts.
  • areas that have already been attacked on the pipes or system parts are preferably washed out by corrosion, so that incipient damaged areas are further damaged. Due to the high pressure water treatment, the treated surface does not become 100% shiny. Some contaminants remain so that the surface appears roughened and new deposits preferentially accumulate there.
  • Such mechanical cleaning typically takes three to four days, including cooling and reheating the furnace.
  • the greatly different thermal conductivity and thermal expansion of the deposits and of the pipe material or of the system parts is used.
  • deposits, pipes or system parts can be removed from the equipment with minimal mechanical stress.
  • the soot or coke-containing impurities can be removed with a pressure of around 12 bar. Air or nitrogen is preferably used as the blowing agent. A 100% shiny metallic surface is achieved, while experience has shown that cleaning with high pressure water only leaves about 80% shiny surfaces.
  • a major advantage of the method according to the invention is that the surfaces can be polished during cleaning, possibly with the addition of abrasion aids.
  • the roughness of the surfaces can be reduced to less than 5 micrometers. The consequence of this is that new deposits do not find a starting point on the smooth surface and consequently not or only very much attach later. This significantly extends the life of the ovens. In practice, a quarter to a half of the mechanical cleaning required can be eliminated, which increases the availability of the furnaces and thus the amount of ethylene produced by about 2 percent per year.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Cleaning In General (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Polishing Bodies And Polishing Tools (AREA)

Abstract

Procédé de traitement d'objets par projection de matière, la matière de projection étant projetée à l'aide d'un flux gazeux sur l'objet à traiter. Selon la présente invention, de la neige carbonique au moins est utilisée comme matière de projection. Lesdits objets traités par projection sont couverts de matériaux ou de revêtements qui d'une part possèdent une dureté supérieure à la neige carbonique, mais d'autre part une conductibilité thermique inférieure à celle de la matière de support de l'objet à laquelle adhèrent les matériaux ou revêtements et / ou sur laquelle se trouvent lesdits matériaux ou revêtements. Ce traitement par projection de matière est effectué de préférence à l'aide de granulés de CO2.
PCT/EP2002/002338 2001-03-08 2002-03-04 Procede de traitement par projection de matiere WO2002072312A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DE50200964T DE50200964D1 (de) 2001-03-08 2002-03-04 Verfahren zur strahlbehandlung mit strahlmitteln
AT02735115T ATE275462T1 (de) 2001-03-08 2002-03-04 Verfahren zur strahlbehandlung mit strahlmitteln
EP02735115A EP1368158B1 (fr) 2001-03-08 2002-03-04 Procede de traitement par projection de matiere

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10111235.1 2001-03-08
DE10111235A DE10111235A1 (de) 2001-03-08 2001-03-08 Verfahren zur Strahlbehandlung mit Strahlmitteln

Publications (1)

Publication Number Publication Date
WO2002072312A1 true WO2002072312A1 (fr) 2002-09-19

Family

ID=7676769

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2002/002338 WO2002072312A1 (fr) 2001-03-08 2002-03-04 Procede de traitement par projection de matiere

Country Status (4)

Country Link
EP (1) EP1368158B1 (fr)
AT (1) ATE275462T1 (fr)
DE (2) DE10111235A1 (fr)
WO (1) WO2002072312A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011088884A1 (fr) 2010-01-25 2011-07-28 Oerlikon Trading Ag; Trübbach Procédé de nettoyage pour des installations de revêtement
WO2013112884A3 (fr) * 2012-01-26 2013-10-10 Alain Turenne Procédé de purification du silicium
WO2013159766A1 (fr) * 2012-04-23 2013-10-31 Koch Industrieanlagen Gmbh Dispositif de nettoyage des portes de fours à coke

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2276186T3 (es) * 2004-05-06 2007-06-16 Siemens Aktiengesellschaft Procedimiento para ajustar la conductividad electrica de un recubrimiento de una pieza constructiva de maquina, cuya conductividad electrica puede modificarse mediante presion, mediante radiacion de hielo seco.

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2627121A1 (fr) * 1988-02-12 1989-08-18 Carboxyque Francaise Procede, installation et buse de projection pour le traitement de pieges par soufflage de grenaille
DE4420579A1 (de) * 1994-06-03 1995-12-07 Meyer & John Gmbh & Co Verfahren zum Reinigen von Rohrleitungen
WO2000067928A2 (fr) * 1999-05-07 2000-11-16 Berndorf Band Gesmbh Dispositif comportant au moins une bande d'acier sans fin, et procede pour soumettre a une contrainte thermique des matieres plastiques

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2627121A1 (fr) * 1988-02-12 1989-08-18 Carboxyque Francaise Procede, installation et buse de projection pour le traitement de pieges par soufflage de grenaille
DE4420579A1 (de) * 1994-06-03 1995-12-07 Meyer & John Gmbh & Co Verfahren zum Reinigen von Rohrleitungen
WO2000067928A2 (fr) * 1999-05-07 2000-11-16 Berndorf Band Gesmbh Dispositif comportant au moins une bande d'acier sans fin, et procede pour soumettre a une contrainte thermique des matieres plastiques

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011088884A1 (fr) 2010-01-25 2011-07-28 Oerlikon Trading Ag; Trübbach Procédé de nettoyage pour des installations de revêtement
DE102010005762A1 (de) 2010-01-25 2011-07-28 Oerlikon Trading Ag, Trübbach Reinigungsverfahren für Beschichtungsanlagen
WO2013112884A3 (fr) * 2012-01-26 2013-10-10 Alain Turenne Procédé de purification du silicium
KR20140114440A (ko) * 2012-01-26 2014-09-26 실리코르 머티리얼즈 인코포레이티드 규소 정제 방법
WO2013159766A1 (fr) * 2012-04-23 2013-10-31 Koch Industrieanlagen Gmbh Dispositif de nettoyage des portes de fours à coke
RU2638986C2 (ru) * 2012-04-23 2017-12-19 Дсд Кох Индустрианлаген Гмбх Устройство для очистки дверей коксовой печи

Also Published As

Publication number Publication date
EP1368158B1 (fr) 2004-09-08
EP1368158A1 (fr) 2003-12-10
DE50200964D1 (de) 2004-10-14
DE10111235A1 (de) 2002-09-19
ATE275462T1 (de) 2004-09-15

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