CA2553755A1 - Urea granulation process - Google Patents
Urea granulation process Download PDFInfo
- Publication number
- CA2553755A1 CA2553755A1 CA002553755A CA2553755A CA2553755A1 CA 2553755 A1 CA2553755 A1 CA 2553755A1 CA 002553755 A CA002553755 A CA 002553755A CA 2553755 A CA2553755 A CA 2553755A CA 2553755 A1 CA2553755 A1 CA 2553755A1
- Authority
- CA
- Canada
- Prior art keywords
- urea
- granulation
- granulator
- granule
- additive
- 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.)
- Granted
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05C—NITROGENOUS FERTILISERS
- C05C9/00—Fertilisers containing urea or urea compounds
- C05C9/005—Post-treatment
-
- 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
- B01J2/16—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by suspending the powder material in a gas, e.g. in fluidised beds or as a falling curtain
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G5/00—Fertilisers characterised by their form
- C05G5/30—Layered or coated, e.g. dust-preventing coatings
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Pest Control & Pesticides (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Fertilizers (AREA)
- Agricultural Chemicals And Associated Chemicals (AREA)
- Glanulating (AREA)
Abstract
Urea granulation process in a granulator that contains urea nuclei, to which a urea melt and at least one granulation additive are added, wherein the urea nuclei are transported and the urea melt is added perpendicularly to the direction of transport of the urea nuclei, wherein the granulation additive is at least partially supplied to the last section of the granulator.
Description
UREA GRANULATION PROCESS
The invention relates to a urea granulation process in a granulator that contains urea nuclei, to which a urea melt and at least one granulation additive are added, wherein the urea nuclei are transported and the urea melt is added perpendicularly to the direction of transport of the urea nuclei.
Such urea granulation processes are described in the Encyclopedia of Chemical Technology, third edition, volume 23, pages 566-572. It discusses among other things the Cominco granulation process, the TVA falling-curtain granulation process, the NSM granulation process and the MitsuiToatsu-Toyo Engineering granulation process, wherein granulation is effected in the manner described above.
The Cominco granulation process and the TVA falling-curtain granulation process employ as a granulator a drum that rotates about its longitudinal axis and so transports nuclei that are supplied at the beginning of the granulator through the granulator, with sprayers being present over a large part of the length of the drum for spraying urea melt. In the NSM granulation process and the MitsuiToatsu-Toyo Engineering granulation process the nuclei are introduced in a fluid bed and transported in the fluid bed, with the nuclei growing to form granules on account of urea melt being sprayed in the fluid bed by sprayers that are positioned along a large part of the length of the fluid bed.
It is known that in these granulation processes formaldehyde or another granulation additive may be added to the urea melt before it is supplied to the granulator so as to improve granulation and to enhance the properties of the urea granules.
A drawback of the known process is that comparatively much granulation additive relative to the urea melt needs to be added in order to achieve the desired improvements.
The object of the invention is to reduce the quantity of granulation additive relative to the urea melt, with urea granulate with comparable properties being obtained.
The invention is characterized in that the granulation additive is at least partially supplied to the last section of the granulator. In this way, less granulation additive is needed for obtaining urea granulate with good properties.
The invention relates to a urea granulation process in a granulator that contains urea nuclei, to which a urea melt and at least one granulation additive are added, wherein the urea nuclei are transported and the urea melt is added perpendicularly to the direction of transport of the urea nuclei.
Such urea granulation processes are described in the Encyclopedia of Chemical Technology, third edition, volume 23, pages 566-572. It discusses among other things the Cominco granulation process, the TVA falling-curtain granulation process, the NSM granulation process and the MitsuiToatsu-Toyo Engineering granulation process, wherein granulation is effected in the manner described above.
The Cominco granulation process and the TVA falling-curtain granulation process employ as a granulator a drum that rotates about its longitudinal axis and so transports nuclei that are supplied at the beginning of the granulator through the granulator, with sprayers being present over a large part of the length of the drum for spraying urea melt. In the NSM granulation process and the MitsuiToatsu-Toyo Engineering granulation process the nuclei are introduced in a fluid bed and transported in the fluid bed, with the nuclei growing to form granules on account of urea melt being sprayed in the fluid bed by sprayers that are positioned along a large part of the length of the fluid bed.
It is known that in these granulation processes formaldehyde or another granulation additive may be added to the urea melt before it is supplied to the granulator so as to improve granulation and to enhance the properties of the urea granules.
A drawback of the known process is that comparatively much granulation additive relative to the urea melt needs to be added in order to achieve the desired improvements.
The object of the invention is to reduce the quantity of granulation additive relative to the urea melt, with urea granulate with comparable properties being obtained.
The invention is characterized in that the granulation additive is at least partially supplied to the last section of the granulator. In this way, less granulation additive is needed for obtaining urea granulate with good properties.
This is advantageous since granulation additives are costly and their addition heavily affects the cost price of urea granulate.
A granulator for granulating urea comprises a casing to one side of which nuclei are supplied. Furthermore, the granulator comprises means of transporting the granules that develop from the nuclei to the opposite side.
In a drum granulator such transport takes place through rotation of the drum granulator and displacement of the granules by the blades present therein.
In a fluid bed granulator the fluid bed is located above a distribution plate. The fluid bed is maintained by the fluidization air supplied through the distribution plate. In a fluid bed granuiator the transport of granules through the granulator is controlled by the supply direction of the fluidization air through the distribution plate.
The urea melt is supplied to the granulator perpendicularly to the transport direction of the nuclei and the urea granulate through the granulator.
Perpendicular here and hereinafter means at an angle of 70-110° to the transport direction of the nuclei and the urea granulate.
The urea melt is supplied to the granulator through sprayers or distributors that are located over almost the full length of the granulator.
According to the process of the invention the granulation additive is now at least partially supplied to the last section of the granulator, that is, the section where the last sprayers or urea melt distributors are present.
Besides the supply of the granulation additive to the last section of the granulator, a portion of the granulation additive may be supplied in a preceding section of the granulator by for example mixing a proportion of the granulation additive with the urea melt before it is added to the granulator. Addition of the granulation additive at least partially to the last granulator section means that at least 50% of the granulation additive is added here. Preferably at least 70% of the granulation additive is supplied to the last granulator section.
The granulation additive may be supplied separately from the urea melt but is preferably mixed with the urea melt before it is supplied to the last granulator section.
Following the last granulator section, prior to the granulate leaving the granulator, the granulator typically contains a zone to which urea melt is not supplied. The granulate is cooled in this zone.
Examples of granulation additives are formaldehyde, methylolurea, formurea, hexamethylene tetramine. Formaldehyde is preferably used as granulation additive for improving the mechanical strength of the urea granules and for reducing the tendency of the urea granules to adhere together during storage (caking behaviour). Formaldehyde may be added as gaseous formaldehyde, formalin, paraformaldehyde, a solution of paraformaldehyde or as urea formaldehyde precondensate.
Formaldehyde is most often added as formaldehyde precondensate.
Formaldehyde precondensate contains for example 60 wt.% formaldehyde.
Preferably 0.01-0.4 wt.% formaldehyde is added to the urea melt relative to the urea added.
The invention also relates to a urea granule containing a granulation additive.
In the processes described in the aforementioned Encyclopedia of Chemical Technology, third edition, volume 23, pages 566-572, the granulation additive is added over the full length of the granulator, as a result of which the concentration of the granulation additive is the same throughout the urea granule. State of the art processes are known whereby the granulation additive is distributed over the surface of the urea granule after the formation of a urea granule, so in essence after the granulation process is completed. Thus, following such a process the granulation additive is present on the urea granule's surface only.
The process according to the invention ensures that the granulation additive is present in the granule such that the concentration of the granulation additive is highest in the outer layer of the granule. The granulation additive is not only present on the surface of the granule, but is solidified together with the urea melt in the outer layer of the granule. Granulation additive may also be present in the rest of the granule.
Preferably, the granulation additive is present in the granule such that its concentration increases from the core to the outside surface of the granule.
The granules according to the invention preferably contain 0,01-0,4 wt.% formaldehyde relative to urea.
In Figure 1 urea granulation process according to the invention is represented. Figure 1 shows a granulator wherein sprayers (S) are present over almost the full length for adding the urea melt originating from a urea plant or a urea melt storage tank (U). Nuclei (N) are supplied to the granulator above a distribution plate.
Fluidization air and secondary air (A) are supplied beneath the distribution plate and to the sprayers, respectively.
At the end of the granulator the granules (G) are discharged. The granulation additive (D) is completely added to the urea melt supply line connecting to the last sprayer.
A granulator for granulating urea comprises a casing to one side of which nuclei are supplied. Furthermore, the granulator comprises means of transporting the granules that develop from the nuclei to the opposite side.
In a drum granulator such transport takes place through rotation of the drum granulator and displacement of the granules by the blades present therein.
In a fluid bed granulator the fluid bed is located above a distribution plate. The fluid bed is maintained by the fluidization air supplied through the distribution plate. In a fluid bed granuiator the transport of granules through the granulator is controlled by the supply direction of the fluidization air through the distribution plate.
The urea melt is supplied to the granulator perpendicularly to the transport direction of the nuclei and the urea granulate through the granulator.
Perpendicular here and hereinafter means at an angle of 70-110° to the transport direction of the nuclei and the urea granulate.
The urea melt is supplied to the granulator through sprayers or distributors that are located over almost the full length of the granulator.
According to the process of the invention the granulation additive is now at least partially supplied to the last section of the granulator, that is, the section where the last sprayers or urea melt distributors are present.
Besides the supply of the granulation additive to the last section of the granulator, a portion of the granulation additive may be supplied in a preceding section of the granulator by for example mixing a proportion of the granulation additive with the urea melt before it is added to the granulator. Addition of the granulation additive at least partially to the last granulator section means that at least 50% of the granulation additive is added here. Preferably at least 70% of the granulation additive is supplied to the last granulator section.
The granulation additive may be supplied separately from the urea melt but is preferably mixed with the urea melt before it is supplied to the last granulator section.
Following the last granulator section, prior to the granulate leaving the granulator, the granulator typically contains a zone to which urea melt is not supplied. The granulate is cooled in this zone.
Examples of granulation additives are formaldehyde, methylolurea, formurea, hexamethylene tetramine. Formaldehyde is preferably used as granulation additive for improving the mechanical strength of the urea granules and for reducing the tendency of the urea granules to adhere together during storage (caking behaviour). Formaldehyde may be added as gaseous formaldehyde, formalin, paraformaldehyde, a solution of paraformaldehyde or as urea formaldehyde precondensate.
Formaldehyde is most often added as formaldehyde precondensate.
Formaldehyde precondensate contains for example 60 wt.% formaldehyde.
Preferably 0.01-0.4 wt.% formaldehyde is added to the urea melt relative to the urea added.
The invention also relates to a urea granule containing a granulation additive.
In the processes described in the aforementioned Encyclopedia of Chemical Technology, third edition, volume 23, pages 566-572, the granulation additive is added over the full length of the granulator, as a result of which the concentration of the granulation additive is the same throughout the urea granule. State of the art processes are known whereby the granulation additive is distributed over the surface of the urea granule after the formation of a urea granule, so in essence after the granulation process is completed. Thus, following such a process the granulation additive is present on the urea granule's surface only.
The process according to the invention ensures that the granulation additive is present in the granule such that the concentration of the granulation additive is highest in the outer layer of the granule. The granulation additive is not only present on the surface of the granule, but is solidified together with the urea melt in the outer layer of the granule. Granulation additive may also be present in the rest of the granule.
Preferably, the granulation additive is present in the granule such that its concentration increases from the core to the outside surface of the granule.
The granules according to the invention preferably contain 0,01-0,4 wt.% formaldehyde relative to urea.
In Figure 1 urea granulation process according to the invention is represented. Figure 1 shows a granulator wherein sprayers (S) are present over almost the full length for adding the urea melt originating from a urea plant or a urea melt storage tank (U). Nuclei (N) are supplied to the granulator above a distribution plate.
Fluidization air and secondary air (A) are supplied beneath the distribution plate and to the sprayers, respectively.
At the end of the granulator the granules (G) are discharged. The granulation additive (D) is completely added to the urea melt supply line connecting to the last sprayer.
Comparative Experiment A
In a urea granulation process according to figure 1 a formaldehyde-containing solution (UFC 85~) was added to the urea melt directly after the evaporators in the urea plant (U). The amount of the formaldehyde-containing solution added, was such that the urea granules obtained after granulation, contained 0.4 wt% of formaldehyde relative to urea. Urea granules were obtained wherein formaldehyde was evenly distributed.
The crushing strength of the granule was determined using an apparatus of Lloyds instruments; type LRX + and has a value of 4.8 kgf determined on a granule with a diameter of 2.85 mm.
Almost no dust formation occurred during transport and handling of the granules.
Example I
In a urea granulation process according to figure 1 a formaldehyde-containing solution (UFC 85~) was partially added to the urea melt directly after the evaporators in the urea plant (U) and partially to the urea melt at place D according to the figure.
The ratio of the amount of the formaldehyde-containing solution added directly after the evaporators and the amount added to place D was 1:2.5. The total amount of the formaldehyde-containing solution that was added was such that the urea granules obtained after granulation, contained 0.2 wt% of formaldehyde relative to urea.
Urea granules were obtained wherein the concentration of formaldehyde in the outer layer of the granule was about 30% higher than the concentration in the middle of the granule.
The crushing strength of the granule was determined as described for Comparative Experiment A and had a value of 4.8 kgf.
Almost no dust formation occurred during transport and handling. With respect to dust formation the product was comparable with the product according to Comparative Experiment A.
In a urea granulation process according to figure 1 a formaldehyde-containing solution (UFC 85~) was added to the urea melt directly after the evaporators in the urea plant (U). The amount of the formaldehyde-containing solution added, was such that the urea granules obtained after granulation, contained 0.4 wt% of formaldehyde relative to urea. Urea granules were obtained wherein formaldehyde was evenly distributed.
The crushing strength of the granule was determined using an apparatus of Lloyds instruments; type LRX + and has a value of 4.8 kgf determined on a granule with a diameter of 2.85 mm.
Almost no dust formation occurred during transport and handling of the granules.
Example I
In a urea granulation process according to figure 1 a formaldehyde-containing solution (UFC 85~) was partially added to the urea melt directly after the evaporators in the urea plant (U) and partially to the urea melt at place D according to the figure.
The ratio of the amount of the formaldehyde-containing solution added directly after the evaporators and the amount added to place D was 1:2.5. The total amount of the formaldehyde-containing solution that was added was such that the urea granules obtained after granulation, contained 0.2 wt% of formaldehyde relative to urea.
Urea granules were obtained wherein the concentration of formaldehyde in the outer layer of the granule was about 30% higher than the concentration in the middle of the granule.
The crushing strength of the granule was determined as described for Comparative Experiment A and had a value of 4.8 kgf.
Almost no dust formation occurred during transport and handling. With respect to dust formation the product was comparable with the product according to Comparative Experiment A.
Claims (9)
1. Urea granulation process in a granulator that contains urea nuclei, to which a urea melt and at least one granulation additive are added, wherein the urea nuclei are transported and the urea melt is added perpendicularly to the direction of transport of the urea nuclei characterized in that the granulation additive is at least partially supplied to the last section of the granulator.
2. Process according to Claim 1, characterized in that at least 70 wt.% of the granulation additive is supplied to the last granulator section.
3. Process according to Claim 1 or 2, characterized in that the granulation additive is mixed with the urea melt before it is supplied to the last granulator section.
4. Process according to any one of Claims 1-3, characterized in that the granulation additive is formaldehyde.
5. Process according to any one of Claims 1-4, characterized in that 0.01-0.4 wt.% formaldehyde is added to the urea melt relative to urea.
6. Urea granule containing a granulation additive, characterized in that the concentration of the granulation additive is highest in the outer layer of the granule.
7. Urea granule according to Claim 6, characterized in that the granulation additive is present in the whole granule such that the concentration of the granulation additive increases from the core to the outside surface.
8. Urea granule according to Claim 6 or 7, characterized in that the granulation additive is formaldehyde.
9. Urea granule according to any one of claims 6-8, characterized in that the granule contains 0,01-0,4 wt.% formaldehyde relative to urea.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL1025805 | 2004-03-25 | ||
| NL1025805A NL1025805C2 (en) | 2004-03-25 | 2004-03-25 | Process for the granulation of urea. |
| PCT/NL2005/000136 WO2005092486A1 (en) | 2004-03-25 | 2005-02-24 | Urea granulation process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2553755A1 true CA2553755A1 (en) | 2005-10-06 |
| CA2553755C CA2553755C (en) | 2013-12-03 |
Family
ID=34960584
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2553755A Active CA2553755C (en) | 2004-03-25 | 2005-02-24 | Urea granulation process |
Country Status (8)
| Country | Link |
|---|---|
| CN (1) | CN100551511C (en) |
| AR (1) | AR049627A1 (en) |
| CA (1) | CA2553755C (en) |
| EA (1) | EA008602B1 (en) |
| EG (1) | EG26185A (en) |
| MY (1) | MY166037A (en) |
| NL (1) | NL1025805C2 (en) |
| WO (1) | WO2005092486A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2431346A1 (en) * | 2010-09-15 | 2012-03-21 | Uhde Fertilizer Technology B.V. | Method for producing urea fertilizer with low moisture absorption tendencies |
| EP2489429A1 (en) * | 2011-02-21 | 2012-08-22 | Urea Casale S.A. | Fluid bed granulation of urea and related apparatus |
| EP3095770A1 (en) * | 2015-05-21 | 2016-11-23 | Casale SA | Process for the production of combined fertilizers |
| EP3594194A1 (en) | 2018-07-12 | 2020-01-15 | Casale Sa | Urea granulation process |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB944875A (en) * | 1959-09-14 | 1963-12-18 | Ici Ltd | Improvements in and relating to urea |
| DE1916368A1 (en) * | 1969-03-29 | 1970-10-01 | Veba Chemie Nord Gmbh | Slow-acting fertilizers |
| JPS5330689B1 (en) * | 1970-03-16 | 1978-08-29 | ||
| CA1101641A (en) * | 1977-06-09 | 1981-05-26 | Anton Niks | Urea granulation |
| JP2515888B2 (en) * | 1989-08-09 | 1996-07-10 | 鹿島建設株式会社 | Construction method of steel pipe pile for building offshore structure and its equipment |
| RU2104258C1 (en) * | 1992-08-07 | 1998-02-10 | Хидро Агри Слейскил Б.В. | Method of granulated urea production |
| JPH09169717A (en) * | 1995-12-19 | 1997-06-30 | Toyo Eng Corp | Production of large granule urea |
| JP3667418B2 (en) * | 1996-02-01 | 2005-07-06 | 東洋エンジニアリング株式会社 | Method for producing granular urea |
-
2004
- 2004-03-25 NL NL1025805A patent/NL1025805C2/en not_active IP Right Cessation
-
2005
- 2005-02-24 CA CA2553755A patent/CA2553755C/en active Active
- 2005-02-24 EA EA200601764A patent/EA008602B1/en not_active IP Right Cessation
- 2005-02-24 WO PCT/NL2005/000136 patent/WO2005092486A1/en active Application Filing
- 2005-02-24 CN CNB2005800094900A patent/CN100551511C/en active Active
- 2005-03-23 AR ARP050101183A patent/AR049627A1/en active IP Right Grant
- 2005-03-24 MY MYPI20051297A patent/MY166037A/en unknown
-
2006
- 2006-09-24 EG EGPCTNA2006000915A patent/EG26185A/en active
Also Published As
| Publication number | Publication date |
|---|---|
| CN1933900A (en) | 2007-03-21 |
| CA2553755C (en) | 2013-12-03 |
| CN100551511C (en) | 2009-10-21 |
| NL1025805C2 (en) | 2005-09-27 |
| EA008602B1 (en) | 2007-06-29 |
| WO2005092486A1 (en) | 2005-10-06 |
| EG26185A (en) | 2013-04-07 |
| AR049627A1 (en) | 2006-08-23 |
| EA200601764A1 (en) | 2007-02-27 |
| MY166037A (en) | 2018-05-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request |