Method for the manufacture of a urea-based composition comprising the addition of an additive in an aqueous form
A method for the manufacture of a homogeneous, solid, particulate, urea-based composition including urea and an additive in a urea production plant with at least an evaporator section and a particulation section, and one or more of a mixing section, an effluent gas treatment section and a scrubber solution storage section. The method includes steps of—: (i) concentrating a urea melt of about 80 weight % to about 95 to 99 weight % of urea-; (ii) particulating a urea or urea-based melt into a urea or urea-based composition; (iii) mixing the urea melt of about 95 to 99 weight % with other fertilizer components to produce a urea-based melt; (iv) treating the effluent gas from the particulation section including urea-based dust particles and ammonia gas with water to produce a scrubber solution; and (v) storing the scrubber solution from the effluent gas treatment section.
1 . A method for the manufacture of a homogeneous, solid, particulate, urea-based composition comprising urea and an additive, in a urea production plant comprising at least an evaporator section, and a particulation section, further comprising at least one of a mixing section, an effluent gas treatment section, and a scrubber solution storage section, wherein the method comprises at least the steps of:
(i) concentrating, in the evaporator section, a urea melt to 95 to 99 weight % of urea;
(ii) particulating, in the particulation section, the urea or the urea melt into a homogeneous, solid, particulate, urea-based composition, thereby producing an effluent gas comprising urea-based dust particles and ammonia gas;
(iii) treating in the effluent gas treatment section, the effluent gas from the particulation section comprising the urea-based dust particles and the ammonia gas with an aqueous solution to produce a scrubber solution; and comprises steps of:
(iv) mixing, in the mixing section the urea melt of 95 to 99 weight % with other fertilizer components to produce the urea melt;
and
(v) storing, in the scrubber solution storage section the scrubber solution from the effluent gas treatment section;
wherein the additive is introduced into the urea melt or the homogeneous, solid, particulate, urea-based composition as an aqueous suspension, an aqueous dispersion, or an aqueous liquid, by adding the additive to at least one of:
(a) said effluent gas treatment section; or
(b) said scrubber solution storage section containing the scrubber solution.
2 . The method according to claim 1 , wherein, the additive is added to the aqueous solution that is used in the effluent gas treatment section for treating the effluent gas from the particulation section comprising the urea-based dust particles and the ammonia gas to produce a scrubber solution.
3 . The method according to claim 2 , further comprising introducing the scrubber solution, including the additive, from the effluent gas treatment section to the evaporator section, the mixing section, or the particulation section.
4 . The method according to claim 1 , wherein the additive is added to said scrubber solution storage section containing the scrubber solution.
5 . The method according to claim 4 , further comprising introducing the scrubber solution, including the additive, from the scrubber solution storage section to the evaporator section, the mixing section, or the particulation section.
6 . The method according to claim 1 , wherein the particulation section is selected from the group consisting of fluidized bed granulator, pan granulator, drum granulator, prilling tower, spherodizer, and pastillizer.
7 . The method according to claim 1 , wherein the additive is at least one of a phosphoric triamide urease inhibitor, a nitrification inhibitor, an alkaline-forming or alkaline inorganic compound, a cation-containing compound, and magnesium sulphate/magnesium oxide mixtures.
8 . The method according to claim 7 , wherein the phosphoric triamide urease inhibitor is a compound of formula:
wherein:
X is oxygen or sulphur;
R 1 is alkyl, cycloalkenyl, aralkyl, aryl, alkenyl, alkynyl, or cycloalkyl;
R 2 is hydrogen, alkyl, cycloalkenyl, aralkyl, aryl, alkenyl, alkynyl, or cycloalkyl; or
R 1 and R 2 together may form an alkylene or alkenylene chain which may optionally include one or more heteroatoms of divalent oxygen, nitrogen or sulphur completing a 4, 5, 6, 7, or 8 membered ring system; and
R 3 , R 4 , R 5 and R 6 are individually hydrogen or alkyl having 1 to 6 carbon atoms.
9 . The method according to claim 8 , wherein the urease inhibitor is added to the urea-based composition at a level of 0.0001 to 1% weight %, relative to the total weight of the urea-based composition.
10 . The method according to claim 9 wherein the urease inhibitor is added to the urea-based composition at a level of 0.02 to 0.2 weight %.
11 . The method according to claim 7 , wherein the nitrification inhibitor is selected from the group consisting of dicyandiamide (DCD); 2-chloro-6-trichloromethylpyridine (nitrapyrin); 3,4-dimethylpyrazole phosphate (DMPP); other dimethylpyrazole (DMP)-based compounds; 3-methylpyrazole (MP); 1-H-1,2,4-triazole (TZ); 3-methylpyrazole-1-carboxamide (CMP); 4-amino-1,2,4-triazole (AT, ATC); 3-amino-1,2,4-triazole; 2-cyanimino-4-hydroxy-6-methylpyrimidine (CP); 2-ethylpyridine; ammonium thiosulfate (ATS); sodium thiosulfate (ST); thiophosphoryl triamide; thiourea (TU); guanylthiourea (GTU); ammonium polycarboxylate; ethylene urea; hydroquinone; phenylacetylene; phenylphosphoro diamidate; neem_cake; calcium carbide; 5-ethoxy-3-trichloromethyl-1,2,4-thiadiazole (etridiazol); 2-amino-4-chloro-6-methylpyrimidine (AM); 1-mercapto-1,2,4-triazole (MT); 2-mercaptobenzothiazole (MBT); 2-sulfanilamidothiazole (ST); 5-amino-1,2,4-thiadiazole; 2,4-diamino-6-trichloromethyl-s-triazine (CL-1580); N-2,5-dichlorophenyl succinanilic acid (DCS); nitroaniline, chloroaniline, and salts thereof.
12 . The method according to claim 11 , wherein the nitrification inhibitor is present in the urea-based composition at a level of 0.0001 to 1 weight %, relative to the total weight of the urea-based composition.
13 . The method according to claim 12 wherein the nitrification inhibitor is present in the urea-based composition at a level of 0.02 to 0.2 weight %.
14 . The method according to claim 7 , wherein the alkaline-forming or alkaline inorganic compound is selected from the group consisting of metal oxides, carbonates, hydroxides, acetates, and any mixture thereof.
15 . The method according to claim 14 wherein the alkaline-forming or alkaline compound is selected from the group of calcium oxide, sodium hydroxide, sodium hydrogen carbonate, sodium carbonate, borax, zinc oxide, magnesium oxide, calcium carbonate, and any mixture thereof.
16 . The method according to claim 14 , wherein the alkaline-forming or alkaline inorganic compound is added to the urea-based composition at a level of 0.02 to 1 weight %, relative to the total weight of the composition.
17 . The method according to claim 16 wherein the alkaline forming or alkaline inorganic compound is added to the urea-based composition at a level of 0.05 to 1 weight %.
18 . The method according to claim 7 , wherein the cation in the cation-containing compound is Ca 2+ , Mg 2+ , Lit, Fe 2+ , Fe 3+ , Al 3+ , Ag + , Cu 2+ , Zn 2+ , Hg 2+ , Pb 2+ , Ba 2+ , or a quaternary ammonium group comprising at least three groups selected from C 1-2 -alkyl, and C 1-2 -hydroxyalkyl.
19 . The method according to claim 18 , wherein the cation-containing compound is added to the urea-based composition at a level of 0.02 to 1 weight %, relative to a total weight of the composition.
20 . The method according to claim 19 wherein the cation-containing compound is added to the urea-based composition at a level of 0.05 to 1 weight %.
21 . The method according to claim 7 , wherein the magnesium sulphate/magnesium oxide mixture is added to the urea-based composition at a level of 0.02 to 1 weight %, relative to a total weight of the composition.
22 . The method according to claim 21 wherein the magnesium sulphate/magnesium oxide mixture is added to the urea-based composition at a level of 0.05 to 1 weight %.
23 . The method according to claim 1 , wherein the solid, particulate, urea-based composition further comprises one or more compounds selected from the group of ammonium nitrate, calcium nitrate, calcium ammonium nitrate, sodium nitrate, ammonium sulphate nitrate, potassium ammonium nitrate, mono-ammonium phosphate (MAP), di-ammonium phosphate (DAP), other ammonium phosphates, calcium bis(dihydrogen orthophosphate), super phosphate, triple superphosphate, rock phosphate, potassium sulphate, potassium magnesium sulphate, ammonium sulphate (AS), urea ammonium sulphate, urea calcium ammonium nitrate, urea ammonium sulphate, potassium chloride (MOP), urea potassium salts (UK), elemental sulphur, or mixtures thereof.
24 . The method according to claim 23 , wherein the solid, particulate, urea-based composition comprises from about 40 to 99 weight % of urea.