GB2028294A - Improvements relating to fertilizers - Google Patents
Improvements relating to fertilizers Download PDFInfo
- Publication number
- GB2028294A GB2028294A GB7927781A GB7927781A GB2028294A GB 2028294 A GB2028294 A GB 2028294A GB 7927781 A GB7927781 A GB 7927781A GB 7927781 A GB7927781 A GB 7927781A GB 2028294 A GB2028294 A GB 2028294A
- Authority
- GB
- United Kingdom
- Prior art keywords
- fertilizer
- salt
- granules
- sludge
- spherical
- 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.)
- Withdrawn
Links
- 239000003337 fertilizer Substances 0.000 title claims abstract description 59
- 150000003839 salts Chemical class 0.000 claims abstract description 41
- 239000008187 granular material Substances 0.000 claims abstract description 36
- 239000010801 sewage sludge Substances 0.000 claims abstract description 20
- 238000005469 granulation Methods 0.000 claims abstract description 10
- 230000003179 granulation Effects 0.000 claims abstract description 10
- 239000010802 sludge Substances 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 20
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical group N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 claims description 12
- 229910052921 ammonium sulfate Inorganic materials 0.000 claims description 12
- 239000001166 ammonium sulphate Substances 0.000 claims description 12
- 235000011130 ammonium sulphate Nutrition 0.000 claims description 12
- 239000007787 solid Substances 0.000 claims description 12
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical group N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 5
- 239000004254 Ammonium phosphate Substances 0.000 claims description 4
- 239000002253 acid Substances 0.000 claims description 4
- 229910021529 ammonia Inorganic materials 0.000 claims description 4
- 229910000148 ammonium phosphate Inorganic materials 0.000 claims description 4
- 235000019289 ammonium phosphates Nutrition 0.000 claims description 4
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 239000010865 sewage Substances 0.000 claims description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 2
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- 229910021653 sulphate ion Inorganic materials 0.000 claims description 2
- 239000001117 sulphuric acid Substances 0.000 claims description 2
- 235000011149 sulphuric acid Nutrition 0.000 claims description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims 2
- 150000001450 anions Chemical class 0.000 claims 2
- 229910019142 PO4 Inorganic materials 0.000 claims 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims 1
- 150000001768 cations Chemical class 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 claims 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims 1
- 239000010452 phosphate Substances 0.000 claims 1
- 230000001747 exhibiting effect Effects 0.000 abstract 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 12
- 239000013078 crystal Substances 0.000 description 9
- 229910052757 nitrogen Inorganic materials 0.000 description 6
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 5
- 229910052698 phosphorus Inorganic materials 0.000 description 5
- 239000011574 phosphorus Substances 0.000 description 5
- 239000007788 liquid Substances 0.000 description 4
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 3
- 238000005054 agglomeration Methods 0.000 description 3
- 230000002776 aggregation Effects 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 239000011591 potassium Substances 0.000 description 3
- 229910052700 potassium Inorganic materials 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 235000015097 nutrients Nutrition 0.000 description 2
- CBXWGGFGZDVPNV-UHFFFAOYSA-N so4-so4 Chemical compound OS(O)(=O)=O.OS(O)(=O)=O CBXWGGFGZDVPNV-UHFFFAOYSA-N 0.000 description 2
- DLYUQMMRRRQYAE-UHFFFAOYSA-N tetraphosphorus decaoxide Chemical compound O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 241000284610 Minoa Species 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 235000021049 nutrient content Nutrition 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- CHWRSCGUEQEHOH-UHFFFAOYSA-N potassium oxide Chemical compound [O-2].[K+].[K+] CHWRSCGUEQEHOH-UHFFFAOYSA-N 0.000 description 1
- 229910001950 potassium oxide Inorganic materials 0.000 description 1
- 159000000001 potassium salts Chemical class 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05B—PHOSPHATIC FERTILISERS
- C05B7/00—Fertilisers based essentially on alkali or ammonium orthophosphates
-
- 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
- B01J2/12—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic in rotating drums
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05C—NITROGENOUS FERTILISERS
- C05C3/00—Fertilisers containing other salts of ammonia or ammonia itself, e.g. gas liquor
- C05C3/005—Post-treatment
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Fertilizers (AREA)
Abstract
Fertilizer granules exhibiting good shape and low hygroscopicity are formed by adding wet sewage sludge to fertiliser salts during or after granulation thereof.
Description
SPECIFICATION
Improvements relating to fertilizers
Synthetic fertilizers are manufactured as liquids or as solids containing nutrients of nitrogen, phosphorus, and potassium salts. The solid fertilizers are generally produced as spherical or semi-spherical granules with each granule containing one or more of the fertilizer salts. Both solid and liquid fertilizers are packaged in a fairly precise manner to provide a fertilizer containing specific percentages of nitrogen, phosphorus, and potassium. These percentages are usually indicated on the package as numbers such as 2-4-2, which translates to 2% nitrogen, 4% phosphorus pentoxide and 2% potassium oxide. Obviously, the process for producing liquid fertilizers is much easier to control than the process for mixing together solid fertilizers.
Granules of different fertilizer salts are mixed together in a desired ratio to provide specific percentages of nitrogen, phosphorus, and potassium. Generally, packaged fertilizers remain homogeneously mixed during packaging, handling, storage and application. There are, however, problems in obtaining semi-spherical (which term is used herein to indicate a granule approximating the desired spherical shape) granules of synthetically prepared, and therefore relatively pure, fertilizer salts as ammonium phosphate and ammonium sulphate particularly the latter. These salts are most easily produced in crystalline form. When granules of a crystalline salt such as ammonium sulphate are mixed with more nearly spherical prills of other fertilizer components, the mixture tends to become segregated.Consequently, when the fertilizer is applied, the percentage of one or more of the fertilizer salts is likely to be wrong.
Another problem with fertilizers is that they exhibit an affinity for water. Therefore, humid air will cause the prills or granules to absorb water and to agglomerate into a huge mass, which is difficult to handle and distribute evenly. Many manufacturers have had to coat the prills with a non-hygroscopic coating to prevent agglomeration. This, of course, requires additional steps and adds to the cost of fertilizers. Cystalline fertilizer salts as ammonium sulphate and ammonium phosphate are very hygroscopic; therefore, it is advantageous to coat the crystals to prevent agglomeration.
Disposal of sewage sludge has become a major problem in most urban areas, adversely affecting both environment and energy consumption. Although both land and water disposal of unprocessed sludge are still widely practised as the only viable alternatives presently available, it is generally recognized that they cannot continue indefinitely. Disposal by burning is extremely inefficient due to the enormous quantity of energy required to drive off water contained by the sludge.
From the foregoing, it is apparent that the major problems associated with both physical handling and disposal of sewage sludge can be reduced by finding fu rther use for the sludge. Raw and activated sewage sludge-commonly contain upwards of 75% by weight of water, and plant nutrients totaling 5-10%. Because of the nutrient content of the sludge, it has been used as a fertilizer, either mixed with fertilizer salts or alone.
In accordance with the invention, in a method of making a granular fertilizer, wet sewage sludge is mixed with at least one fertilizer salt during or after granulation thereof, and at least a portion of the water is removed from the granules.
If the sewage sludge is applied after granulation of the, preferably crystalline salt(s), it will form a coating on the granules, and if during granulation it will be uniformly mixed with the salt(s) in the granules. In either case the method provides granules fertilizer salts having improved shape, enlarged size, and reduced hygroscopicity as compared to conventional granulated fertilizer products, whilst providing a convenient and useful means for disposing of sewage sludge.
The sewage sludge may be mixed with the salt(s) during granulation thereof in a method comprising:
a) mixing a fertilizer salt-producing acid and base in a mixing vessel;
b) adding wet sewage sludge to the vessel;
c) controlling the temperature and moisture level within the vessel to cause the formation of solid, individual granules of fertilizer salt and sludge solids; and,
d) removing at least a portion of the water from the granules to produce substantially dry, semi-spherical fertilizer granules.
Semi-spherical granules of fertilizer salts, which normally do not led themselves to spherical shapes, can thus be made. This arises from the effect that sewage sludge has on the crystallization process of inorganic, particularly ammonium, salts. It is well known from theoretical chemistry that crystallization of inorganic salts are usually modified by impurities in the precipitating medium and this is well illustrated in this aspect ofthe invention.
In carrying out the new method, a crystalline fertilizer salt, or the reactants to produce a fertilizer salt, or a combination of these two that could result from recycling a portion of the product as to balance wateritemperature variables, may be mixed with wet sludge in a fertilizer granulation process such as a rotating drum. The proportions are generally 10% by weight of sludge to 90% by weight of effluent fertilizer salts. This will vary widely, depending not only on the wetness of the sludge and the hygroscopicity of the crystalline fertilizer salt, but upon the local economics. In some locations, sludge disposal may be at an economic premium while in other instances the production of a semi-spherical granule may be the dominant objective.Most sewage sludges have about 75% water by weight; actual water contents range from 50-60% (depending on whether sludge was filtered and/or allowed to evaporate in holding ponds or on sand beds) up to 90%. The wet sludge not only affects the crystallization process of virgin solids, but also dissolves and e-precipitates the solid fertilizer salts already existing in the granulator. The net result is the production of a ;emi-spherical granule of a fertilizer salt contaning sewage sludge which can then be dried to produce a nost desirable fertilizer product.Further reduction in hygroscopicity can be obtained by either selectively controlling addition of sludge only at the end of the cycle (in a batch operation) or by the subsequent addition of sludge only in a separate vessel to form a coating of sludge on the individual granules.
The accompanying drawing is a diagrammatic iliustration of a rotary granulator which may be used to produce prills in accordance with the method of this invention.
As shown in the drawing, sulphate acid and ammonia may be mixed in a granulation drum 10, and wet sewage sludge added. The sulphuric acid and ammonia react according to the well-known process for forming ammonium sulphate. Heatfrom an external heat source 16and/oran infrared lamp 18crystalizethe ammonium sulphate. As the crystals are formed wet sludge, which has been added to the granulation drum 10 from a hopper 12 and a chute 14, uniformly adheres to the crystals and fill the voids therein forming spherical or semi-spherical granules. Air from a blower 20 circulates in the interior of the drum to withdraw moisture and fumes from the drum. The granulation drum 10, may be rotated by a motor 22.
Specific examples of experiments demonstrating this process are as follows:
Example I
A crystalline ammonium sulphate and a typical municipal sewage sludge obtained from the Syracuse
Minoa sludge plant were introduced into the rotating granulator 10 through hopper 12 and chute 14. Heat from heat source 16 and infrared lamp 18 were applied to the exterior of the granulator 10. As the ammonium sulphate and sewage sludge cascade and mix together in the granulator 10, moisture is driven from the sewage sludge, which was found to contain about 75% water by weight. The sewage sludge adheres to the surface of the ammonium sulphate crystals and fills the voids in the crystals, forming uniform, spherical prills, or semi-spherical granules.
The results of this somewhat crude experiment showed that the resulting granules were enlarged and that the sludge was uniformly spread on the surface of the ammonium sulphate crystals.
Example Il Using a commercial grade fertilizer containing 10% nitrogen, 20% phosphorus, and 20% potassium in place of the ammonium sulphate crystals of Example I, it was found that the prills were similarly enlarged and uniformly coated with sludge.
Example III 709 of ammonium sulphate crystal was mixed with 50g of sewage sludge in a rotating granulator in accordance with Example I.
Quantitative measurements taken on a dry basis showed that the resulting granules contained 15.1% sludge.
Example IV
65g of granular fertilizer containing 11% nitrogen and 48% phosphorus was mixed with 409 of sewage sludge in accordance with Example I.
The results of the quantitative measurements taken on a dry basis showed that the resulting granules contained 13.2% sludge.
The effectiveness of granule size enlargement of Examples Ill and IV was measured by determining the quantity of a petroleum solvent, in which fertilizer salt granules are incoluble, required to fill the void spaces in a measured quantity of granules. The results of this test are as follows:
Ammonium Ammonium 11-48-0 11-48-0
Sulphate Sulphate & ludge
& sludge wtofgranules 249 149 139 10g density of granules 1.035 0.69 1.035 0.69
Vol. of granules 28cc 20.3cc 12.6cue 14.5cue Vol. of kerosene 8.45cc 8.45cc 4.23cc 9.85cc % of voids 30% 41.75% 33.5% 68% % increase of voids 39% 103%
The significance of the above test is high amount of enlargement of the fertilizer salt crystals when granulated with sludge.In the case of the 11-48-0 fertilizer prills, agglomeration occured which indicates that crystalline ammonium phosphate would also exhibit size enlargement when granulated with sludge.
To measure the hygroscopicity of the fertilizer salts and 11-48-0 fertilizer prills with and without sludge, the salts were enclosed in a humidity chamber. The salts were treated separately by being exposed to water vapour, without contact with liquid water. The results of these tests are as follows:
Ammonium Ammonium 11-48-0 11-48-0
Sulphate Sulphate & ludge
Granules & ludge InitialWt 11g llg 25g 199
Wt after 26 hours 12g 11g 299 19g
Water pick-up (g) 1 0 4 0 % Water pick-up 9.1% 0 16% 0
There was no further increase in weight observed after an additional 12 hours in the humidity chamber.
The results of these tests show that granulating the fertilizer salts with sludge significantly reduced hygroscopicity.
Claims (14)
1. A method of making a granular fertilizer wherein wet sewage sludge is mixed with at least one fertilizer salt during or after granulation thereof, and at least a portion of the water is removed from the granules.
2. A method according to claim 1, wherein the dewatering is carried out by application of heat from non-solar sources other than chemical reaction heat.
3. A method according to claim 1 or claim 2, wherein the, or at least one, salt is crystalline in structure.
4. A method according to any one of claims 1 to 3, wherein the salt is ammonium sulphate or ammonium phosphate.
5. A method according to claim 1 or claim 2, the method comprising:
a) mixing a fertilizer salt-producing acid and base in a mixing vessel;
b) adding wet sewage sludge to the vessel;
c) controlling the temperature and moisture level within the vessel to cause the formation of solid, individual granules of fertilizer salt and sludge solids; and,
d) removing at least a portion of the water from the granules to produce substantially dry, semi-spherical fertilizer granules.
6. A method according to claim 5 wherein the acid is sulphuric acid or phosphoric acid.
7. A method according to claim 5 or claim 6, wherein the base is ammonia.
8. A method according to claim 1, substantially as described with reference to any one of the examples.
9. A granular fertilizer made by a method according to any one of the preceding claims.
10. A fertilizer product comprising substantially dry, semi-spherical granules each consisting essentially of a substantially uniform mixtue of a fertilizer salt and sewage slude solids.
11. A fertilizer product comprising substantially dry, semi-spherical granules each consisting essentially of a fertilizer salt substantially completely coated by sewage sludge solids.
12. A product according to claim 10 or claim 11, wherein ammonia is one of the cations contained in the fertilizer salt.
13. A product according to any one of claims 10 to 12, wherein sulphate is one of the anions contained in the fertilizer salt.
14. A product according to any one of claims 10 to 12, wherein phosphate is one of the anions contained in the fertilizer salt.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US93266278A | 1978-08-10 | 1978-08-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2028294A true GB2028294A (en) | 1980-03-05 |
Family
ID=25462684
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7927781A Withdrawn GB2028294A (en) | 1978-08-10 | 1979-08-09 | Improvements relating to fertilizers |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS5551787A (en) |
| DE (1) | DE2931949A1 (en) |
| GB (1) | GB2028294A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4565563A (en) * | 1978-08-10 | 1986-01-21 | Talbert Norwood K | Method of producing fertilizer product containing sewage sludge |
| CN110325289A (en) * | 2016-12-28 | 2019-10-11 | 沙特基础工业全球技术公司 | The recycling design from purge stream |
| CN110366453A (en) * | 2016-12-27 | 2019-10-22 | 沙特基础工业全球技术公司 | Coating drying using electromagnetic radiation or drum heating |
-
1979
- 1979-08-07 DE DE19792931949 patent/DE2931949A1/en not_active Withdrawn
- 1979-08-09 GB GB7927781A patent/GB2028294A/en not_active Withdrawn
- 1979-08-10 JP JP10140579A patent/JPS5551787A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4565563A (en) * | 1978-08-10 | 1986-01-21 | Talbert Norwood K | Method of producing fertilizer product containing sewage sludge |
| CN110366453A (en) * | 2016-12-27 | 2019-10-22 | 沙特基础工业全球技术公司 | Coating drying using electromagnetic radiation or drum heating |
| EP3562597A4 (en) * | 2016-12-27 | 2020-08-26 | SABIC Global Technologies B.V. | DRYING A COATING USING ELECTROMAGNETIC RADIATION OR HEATING A DRUM |
| EP3928879A1 (en) * | 2016-12-27 | 2021-12-29 | SABIC Global Technologies B.V. | Drying a coating using electromagnetic radiation or heating of drum |
| CN110366453B (en) * | 2016-12-27 | 2022-04-05 | 沙特基础工业全球技术公司 | Drying of coatings by electromagnetic radiation or roller heating |
| US11492300B2 (en) | 2016-12-27 | 2022-11-08 | Sabic Global Technologies B.V. | Drying a coating using electromagnetic radiation or heating of drum |
| CN110325289A (en) * | 2016-12-28 | 2019-10-11 | 沙特基础工业全球技术公司 | The recycling design from purge stream |
| US11291944B2 (en) | 2016-12-28 | 2022-04-05 | Sabic Global Technologies B.V. | Solvent recovery from sweep gas streams |
| CN110325289B (en) * | 2016-12-28 | 2022-04-08 | 沙特基础工业全球技术公司 | Recovery of solvent from purge gas stream |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2931949A1 (en) | 1980-02-21 |
| JPS5551787A (en) | 1980-04-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |