US20070131381A1 - Method for belt conditioning in pelletizing plants, method for pelletizing urea and pelletizing plant - Google Patents

Method for belt conditioning in pelletizing plants, method for pelletizing urea and pelletizing plant Download PDF

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Publication number
US20070131381A1
US20070131381A1 US11/593,139 US59313906A US2007131381A1 US 20070131381 A1 US20070131381 A1 US 20070131381A1 US 59313906 A US59313906 A US 59313906A US 2007131381 A1 US2007131381 A1 US 2007131381A1
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US
United States
Prior art keywords
product
steel belt
washing liquid
pelletizing
pelletized
Prior art date
Legal status (The legal status 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 status listed.)
Abandoned
Application number
US11/593,139
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English (en)
Inventor
Konrad Schermutzki
Hans-Kurt Schromm
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Santrade Ltd
Original Assignee
Santrade Ltd
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 Santrade Ltd filed Critical Santrade Ltd
Assigned to SANTRADE LTD. reassignment SANTRADE LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SCHERMUTZKI, KONRAD, SCHROMM, HANS-KURT
Publication of US20070131381A1 publication Critical patent/US20070131381A1/en
Abandoned legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
    • B01J2/26—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic on endless conveyor belts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B9/00—Making granules
    • B29B9/10—Making granules by moulding the material, i.e. treating it in the molten state
    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05C—NITROGENOUS FERTILISERS
    • C05C9/00—Fertilisers containing urea or urea compounds
    • C05C9/005—Post-treatment

Definitions

  • the invention relates to a method for belt conditioning in pelletizing plants with a rotating steel belt to which is applied in drop-like manner a melt of a product to be pelletized which is then solidified on the steel belt.
  • the invention also relates to a method for pelletizing urea and to a pelletizing plant for performing the inventive method.
  • a melt of a product to be pelletized is forced into a heated inner body and an outer tube provided with numerous holes and which rotates concentrically about the fixed inner body and deposits product drops over the entire width of a rotating steel belt. Water is sprayed onto the underside of the steel belt, so as to dissipate the heat released during the solidification of the melt and the cooling of the then formed pellets.
  • the pellets are then removed from the steel belt in the vicinity of a reversal thereof by means of a scraper. On removal the pellets have cooled to such an extent that they can be stored and transported as bulk material.
  • a pellet quality is defined by a high pellet shape approaching a spherical shape. If the steel belt is moist during product melt application, the product drops applied run apart, so that flat cake-like pellets are formed. In extreme cases adjacent product drops solidify together to give irregular pellet shapes. If dust-like product residues are collected on the steel belt, they can absorb moisture from the ambient air and once again reduce the pellet quality, because the melt applied absorbs moisture from the moist product residues and consequently gives rise to the formation of flat drops.
  • the problem of the invention is to ensure a high and constant pellet quality with low apparatus and energy costs, even under unfavourable environmental conditions and/or when pelletizing hygroscopic products.
  • the invention provides a method for belt conditioning in pelletizing plants with a rotating steel belt, to which is applied in drop-like manner a melt of a product to be pelletized which is then solidified on the steel belt involving the steps of washing off product residues present on the steel belt after removing the solidified pellets using a washing liquid, which at least contains the dissolved product, and drying the washing liquid adhering to the steel belt for forming a dry product film on said belt prior to the renewed application of a melt of a product to be pelletized.
  • the steel belt is drawn off after washing for forming a washing liquid film adhering to said steel belt.
  • the dry product film has a thickness of less than 5 ⁇ m, particularly less than 1 ⁇ m.
  • a product film with such a limited thickness can be rapidly formed by drying, so that it is also possible to set high belt rotation speeds.
  • the product film cannot lead to a contamination of the pellets produced, because it is itself formed from the product to be pelletized. After removing the pellets, the product film is washed off again and supplied to the washing liquid.
  • the washing liquid also leads to no contamination, but instead must be merely kept at the desired solution concentration by the supply of solvents, particularly water, as well as the product.
  • the washing liquid exclusively comprises a solution of the product with a solvent.
  • a solvent is used as the solvent.
  • the washing liquid only contains the product to be pelletized and the solvent, particularly water, the washing liquid leads to no contamination and no waste quantities are in principle produced.
  • the use of water as the solvent is inexpensive and environmentally friendly, because no environmentally prejudicial solvent vapours are formed.
  • the washing liquid is an unsaturated product solution, so that product residues to be washed from the steel belt can still dissolve and consequently a reliable, thorough cleaning is ensured.
  • the steel belt and/or the air surrounding the latter is heated for drying the detergent film adhering to the said belt.
  • the additional heating of the steel belt and/or the surrounding air can lead to a satisfactory pellet quantity.
  • the heating of the belt leads to a lower relative atmospheric humidity in the boundary layer area of the belt and to a faster product film drying. Heating of the surrounding air increases the ambient temperature whilst simultaneously reducing the atmospheric humidity, so that this also leads to a faster product film drying.
  • Appropriately additional heating is provided in the vicinity of the lower strand of the rotating steel belt.
  • the product to be pelletized is urea.
  • the washing liquid contains between 40% and 80%, particularly 50% water and between 60% and 20%, particularly 50% of the product to be pelletized, particularly urea.
  • the washing liquid contains an agent for preventing agglomeration of the pelletized product and/or caking of the product to be pelletized on the steel belt.
  • the agent is advantageously a urea-formaldehyde reaction product. It is also advantageous for the washing liquid to contain 2% to 8%, particularly 5% of the so-called anti-caking agent.
  • an anti-caking agent can be added to the washing liquid. Although such an anti-caking agent is detectable in the end product, it is acceptable for certain products.
  • the fundamental problem of the invention is also solved by a method for pelletizing urea using the inventive belt conditioning method.
  • the fundamental problem of the invention is also solved by a pelletizing plant with a rotating steel belt to which is applied in drop-like manner a melt of a product to be pelletized which is then solidified on the steel belt, in which means are provided for washing off product residues present on the steel belt after removing the solidified pellets using a washing liquid containing at least the dissolved product, and for forming a dry product film on the steel belt prior to the renewed application of a melt of a product to be pelletized.
  • the pelletizing plant according to the invention can be operated with high belt rotation speeds even under unfavourable climatic conditions and specifically high atmospheric humidity.
  • the pelletizing plant according to the invention permits a high pellet output, even in the case of hygroscopic products, e.g. urea.
  • the means have a washing device downstream of a point for removing solidified product pellets from the steel belt, the washing device having a roller for the application of the washing liquid extending over the entire width of and engaging on the steel belt.
  • the roller advantageously engages on the steel belt and is driven by the latter, so that there is no need to provide an additional drive for the washing device.
  • the roller can have a smooth surface and engages substantially linearly on the steel belt.
  • the roller feeds washing liquid to the steel belt and the washing liquid collects in a cross-sectionally wedge-shaped area between the roller and belt. Despite an in extreme case only linear contact between roller and steel belt, the washing liquid is consequently a really applied to the belt.
  • the roller can have a plastic surface.
  • the roller dips sectionally into a tank fillable with washing liquid.
  • the construction costs for the washing device are further reduced, because there is no need to provide pumps or nozzles in order to bring the washing liquid onto the steel belt.
  • On rotating the roller washing liquid adheres to its surface and is applied to the steel belt in the vicinity of the contact point between the latter and the roller.
  • the means have at least one elastic draw-off lip engaging on the steel belt positioned downstream of the roller in the belt running direction.
  • the means have heating coils under the return strand of the steel belt and/or at least on a heating drum engaging on the steel belt return strand.
  • FIG. 1A diagrammatic representation of an inventive pelletizing plant for performing the inventive method.
  • FIG. 2 A diagrammatic representation of another embodiment of an inventive pelletizing plant for performing the inventive method.
  • FIG. 1 diagrammatically shows a pelletizing plant 10 for pelletizing urea.
  • Urea is a meltable product, but in both the solidified and in the melt-like state it is hygroscopic. Urea pellets are e.g. used in fertilizer manufacture.
  • a urea melt is fed through a supply line 12 to a so-called rotoformer 14 , which comprises a fixed, heated inner body and an outer tube provided with a plurality of holes and which rotates concentrically about the fixed inner body and deposits the urea melt in drop-like manner over the entire width of the rotating steel belt 16 .
  • the urea drops carry the reference numeral 18 in FIG. 1 .
  • Steel belt 16 conveys away the urea drops 18 and during conveying on the upper strand of belt 16 they solidify, so that they can be removed as solid pellets from steel belt 16 using a removal device 20 in the area where said belt is reversed.
  • the upper strand of steel belt 16 is sprayed from below with cooling water from nozzles 22 positioned above a cooling liquid tank 24 .
  • Steel belt 16 is reversed about two spaced drums 26 , 28 , which rotate clockwise in each case, as indicated by the arrows in FIG. 1 .
  • the pellets removed by means of the removal device 20 are collected in a container 30 and are supplied there, e.g. by means of a line 32 to a further processing or intermediate storage.
  • a container 30 On removal from steel belt 16 the urea pellets have solidified and cooled to such an extent that they can be conveyed on and stored in bulk material form.
  • the steel belt 16 can be covered with product residues, which absorb moisture from the ambient air.
  • the urea drops 18 can consequently absorb moisture from product residues on steel belt 16 and therefore assume a flat cake-like shape. This effect naturally occurs if there is a high atmospheric humidity level.
  • a washing and draw-off device 34 is provided in which, in the vicinity of reversing drum 28 , any adhering product residues are cleaned from steel belt 16 which is simultaneously provided with a thin washing liquid film, which during movement along the lower strand to reversing drum 16 dries to a thin product film.
  • the washing device 34 has a roller 36 , which on the one hand is in contact with steel belt 16 and is driven by the latter. On the other roller 36 is sectionally immersed in a washing liquid tank 38 .
  • roller 36 supplies washing liquid to steel belt 16 , so that any product residues which may be on said belt are dissolved and washed away by the washing liquid.
  • the two draw-off lips 40 , 42 can be replaced separately from one another, so that replacement thereof can take place without interrupting the operation of pelletizing plants 10 , 20 and therefore without stopping steel belt 16 .
  • the washing liquid is constituted by an unsaturated urea solution containing 50% urea and 50% water. It has surprisingly been found that such a urea solution has a very good washing action and is able to reliably wash away urea residues adhering to the steel belt 16 and furthermore said urea solution dries more rapidly than water alone. Even in the case of high rotation speeds of steel belt 16 , this ensures that the washing liquid film has completely dried on renewed application of the urea melt by means of rotoformer 14 and it is consequently ensured that the urea drops 18 absorb little or no moisture quantities from the steel belt 16 .
  • the product film formed on steel belt 16 after washing liquid film drying has a very limited thickness of less than 5 ⁇ m, particularly less than 1 ⁇ m.
  • washing liquid only contains urea and water
  • the application of washing liquid and the resulting urea film cannot negatively influence product purity.
  • there are no washing liquid waste quantities because only urea residues are washed away and dissolve again in the washing liquid and do not have to be disposed of.
  • the washing liquid in container 38 is produced in a mixer 44 , which is on the one hand supplied with urea pellets from pellet container 30 and on the other water from a water tank 46 .
  • a water supply line to washing liquid container 38 so as to be able to set a desired urea solution concentration.
  • FIG. 2 shows a pelletizing plant 20 for pelletizing urea, which is in principle identical to pelletizing plant 10 of FIG. 1 . Therefore identically constructed and functioning elements compared with those of pelletizing plant 10 of FIG. 1 are not described again. Differences compared with pelletizing plant 10 of FIG. 1 occur in pelletizing plant 20 with respect to a heated reversing drum 48 .
  • FIG. 2 shows in a purely diagrammatic manner heating coils 50 , which are intended to heat an outer circumference of reversing drum 48 and consequently steel belt 16 .
  • the heating of steel belt 16 serves to more rapidly dry the washing liquid film applied by washing device 34 and consequently make it possible to operate with an even higher rotational speed of steel belt 16 and/or under extremely unfavourable climatic conditions, specifically a tropical climate, to make it reliably possible to provide a thin, dry product film when urea melt is again applied to the steel belt, thereby ensuring a high pellet quality.
  • heating coils 52 with which the air surrounding steel belt 16 is heated. Heating coils 52 also contribute to a rapid drying of the washing liquid film on steel belt 16 so as to give a thin product film.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Detergent Compositions (AREA)
  • Drying Of Solid Materials (AREA)
  • Cleaning By Liquid Or Steam (AREA)
  • Hydroponics (AREA)
  • Manufacture And Refinement Of Metals (AREA)
US11/593,139 2005-11-08 2006-11-06 Method for belt conditioning in pelletizing plants, method for pelletizing urea and pelletizing plant Abandoned US20070131381A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102005054462A DE102005054462B4 (de) 2005-11-08 2005-11-08 Verfahren zur Bandkonditionierung bei Pastillieranlagen
DE102005054462.2 2005-11-08

Publications (1)

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US20070131381A1 true US20070131381A1 (en) 2007-06-14

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US11/593,139 Abandoned US20070131381A1 (en) 2005-11-08 2006-11-06 Method for belt conditioning in pelletizing plants, method for pelletizing urea and pelletizing plant

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US (1) US20070131381A1 (it)
CN (1) CN1962042B (it)
AT (1) AT502737B1 (it)
DE (1) DE102005054462B4 (it)
IT (1) ITPD20060407A1 (it)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100288005A1 (en) * 2007-12-11 2010-11-18 Hans-Kurt Schromm Method and drop former for producing tablets and method for producing a sulfurous fertilizer
US20120187223A1 (en) * 2009-05-20 2012-07-26 Stamicarbon B.V. Process for producing granules
US8303872B2 (en) 2007-12-21 2012-11-06 Basf Se Ethylene urea displaying lasting powder flow
WO2013062410A1 (en) * 2011-10-24 2013-05-02 Stamicarbon B.V. Method of making controlled release fertilizer particles
EP2716620A2 (en) 2012-10-02 2014-04-09 SBS Steel Belt Systems S.R.L. Process and apparatus for producing fertiliser in pellet form
CN105371672A (zh) * 2015-12-14 2016-03-02 吉林市道特化工科技有限责任公司 一种加热结片机钢带的方法
WO2020046936A1 (en) * 2018-08-30 2020-03-05 Dow Global Technologies Llc Apparatus and method for granulating low viscosity materials
US10675603B2 (en) 2014-12-03 2020-06-09 Ipco Germany Gmbh Device and method for pastillating a flowable product
EP4001246A1 (en) 2020-11-20 2022-05-25 Clariant Produkte (Deutschland) GmbH Vinasse containing fertilizer

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010007390A1 (de) * 2010-02-02 2011-08-04 Sandvik Materials Technology Deutschland GmbH, 40549 Verfahren zur Bandkonditionierung bei Pastillieranlagen und Vorrichtung zum Herstellen von Pastillen
DE102010007391A1 (de) * 2010-02-02 2011-08-04 Sandvik Materials Technology Deutschland GmbH, 40549 Verfahren zur Bandkonditionierung bei Pastillieranlagen und Vorrichtung zum Herstellen von Pastillen

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4297091A (en) * 1980-03-10 1981-10-27 Strefling Michael R Alfalfa pelletizing apparatus

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1497391A1 (de) * 1951-01-28 1969-06-04 Agfa Gevaert Ag Vorrichtung zur kontinuierlichen Erstarrung und Zerkleinerung gelatinehaltiger Halogensilberemulsionen
US4189458A (en) * 1976-12-20 1980-02-19 Standard Oil Company A Corporation Of Indiana Method for converting polymer powder to pellets
DE4130341C2 (de) * 1991-09-12 1994-04-21 Pkl Verpackungssysteme Gmbh Formstabiler Schmelzhaftkleber und Verfahren zu seiner Herstellung
US5633018A (en) * 1995-01-20 1997-05-27 E. I. Du Pont De Nemours And Company Apparatus for forming crystalline polymer pellets
DE29610971U1 (de) * 1996-06-22 1996-08-29 Santrade Ltd., Luzern Kühleinrichtung für aus Schmelzen gewonnene Produkte
DE10004174A1 (de) * 2000-02-01 2001-08-09 Santrade Ltd Vorrichtung zur Herstellung und Umhüllung von Schmelzenportionen

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4297091A (en) * 1980-03-10 1981-10-27 Strefling Michael R Alfalfa pelletizing apparatus

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8349229B2 (en) 2007-12-11 2013-01-08 Sandvik Materials Technology Deutschland Gmbh Method and drop former for producing tablets and method for producing a sulfurous fertilizer
US20100288005A1 (en) * 2007-12-11 2010-11-18 Hans-Kurt Schromm Method and drop former for producing tablets and method for producing a sulfurous fertilizer
US8303872B2 (en) 2007-12-21 2012-11-06 Basf Se Ethylene urea displaying lasting powder flow
US20120187223A1 (en) * 2009-05-20 2012-07-26 Stamicarbon B.V. Process for producing granules
US8622325B2 (en) * 2009-05-20 2014-01-07 Stamicarbon B.V. Process for producing granules
US9120709B2 (en) 2011-10-24 2015-09-01 Stamicarbon B.V. Method of making controlled release fertilizer particles
WO2013062410A1 (en) * 2011-10-24 2013-05-02 Stamicarbon B.V. Method of making controlled release fertilizer particles
EP2716620A2 (en) 2012-10-02 2014-04-09 SBS Steel Belt Systems S.R.L. Process and apparatus for producing fertiliser in pellet form
EP3636624A1 (en) 2012-10-02 2020-04-15 SBS Steel Belt Systems S.R.L. Process and apparatus for producing a fertilizer in pellet form
US10675603B2 (en) 2014-12-03 2020-06-09 Ipco Germany Gmbh Device and method for pastillating a flowable product
CN105371672A (zh) * 2015-12-14 2016-03-02 吉林市道特化工科技有限责任公司 一种加热结片机钢带的方法
WO2020046936A1 (en) * 2018-08-30 2020-03-05 Dow Global Technologies Llc Apparatus and method for granulating low viscosity materials
US12070876B2 (en) 2018-08-30 2024-08-27 Dow Global Technologies Llc Apparatus and method for granulating low viscosity materials
EP4001246A1 (en) 2020-11-20 2022-05-25 Clariant Produkte (Deutschland) GmbH Vinasse containing fertilizer

Also Published As

Publication number Publication date
DE102005054462B4 (de) 2009-08-06
ITPD20060407A1 (it) 2007-05-09
AT502737B1 (de) 2008-06-15
DE102005054462A1 (de) 2007-05-10
AT502737A2 (de) 2007-05-15
CN1962042B (zh) 2011-05-04
CN1962042A (zh) 2007-05-16

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AS Assignment

Owner name: SANTRADE LTD., SWITZERLAND

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SCHERMUTZKI, KONRAD;SCHROMM, HANS-KURT;REEL/FRAME:018964/0312

Effective date: 20061220

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION