A urea preparation machine includes a cabinet, a stirring tank, a filtering portion, a water tank portion and a heating portion. The stirring tank is provided in the cabinet. The filtering portion is provided in the cabinet. An inlet of the water tank portion s communicated with an outlet of the filtering portion. The heating portion is provided in the cabinet, the heating portion is communicated with the outlet of the water tank portion, and an outlet of the heating portion is communicated with the stirring tank. The independent heating portion is used for heating water in the water tank portion, then the water heated by the heating portion is conveyed to the stirring tank for preparing urea, through such installation, the heating portion is capable of heating the water in the water tank portion in time.

Disclosed is a method for the removal of urea dust from the off-gas of a finishing section (1) of a urea production plant, the method comprises subjecting the off-gas to quenching with water (06) so as to produce quenched off-gas, and subjecting the quenched off-gas to scrubbing using at least one venturi scrubber (11). As a result, a lower pressure drop over the scrubber is attained, and a more efficient growth of urea particles, facilitating the removal thereof.

Disclosed is a method for the removal of urea dust from the off-gas of a finishing section (1) of a urea production plant, the method comprises subjecting the off-gas to quenching with water (06) so as to produce quenched off-gas, and subjecting the quenched off-gas to scrubbing using at least one venturi scrubber (11). As a result, a lower pressure drop over the scrubber is attained, and a more efficient growth of urea particles, facilitating the removal thereof.

Disclosed is a method for the removal of urea dust from the off-gas of a finishing section of a urea production plant. the method comprises subjecting the off-gas to quenching with water so as to produce quenched off-gas. The quenched off-gas is subjected to humidification by mixing said quenched gas stream with a humidification fluid selected from (a) saturated steam and (b) superheated steam mixed with a second aqueous stream, so as to produce a humidified gas stream, subjecting said humidified gas stream to particle separation (i.e., dust removal) by means of a scrubbing liquid in which at least part of the particles in the gas stream are soluble.

The present invention discloses a synthetic procedure for the preparation of Methylliberine and its polymorphs thereof in a simple and efficient manner.

The present invention discloses a synthetic procedure for the preparation of Methylliberine and its polymorphs thereof in a simple and efficient manner.

A distribution chamber suitable for distributing a liquid stream to a plurality of pipe openings distributed over a planar surface. The distribution chamber includes three perforated plates. A method to distribute a liquid stream to a plurality of pipe openings, a method to decompose ammonium carbamate from an aqueous solution comprising ammonium carbamate and a method to produce a concentrated aqueous urea solution from a diluted aqueous urea solution.

A distribution chamber suitable for distributing a liquid stream to a plurality of pipe openings distributed over a planar surface. The distribution chamber includes three perforated plates. A method to distribute a liquid stream to a plurality of pipe openings, a method to decompose ammonium carbamate from an aqueous solution comprising ammonium carbamate and a method to produce a concentrated aqueous urea solution from a diluted aqueous urea solution.

The present invention discloses a method of quickly desorbing phosgene from a catalyst in a phosgene synthesizing tower when the catalyst in the phosgene synthesizing tower is replaced. The method is carried out by first purging out easily-desorbed phosgene from the catalyst activated carbon in the phosgene synthesizing tower with nitrogen gas, then purging with ammonia gas, and the ammonia gas is reacted with the hardly-desorbed phosgene in the catalyst of the phosgene synthesizing tower. Then the phosgene synthesizing tower is rinsed with a water gun and then dried with hot gas. The phosgene content at an outlet of the phosgene synthesizing tower after purging is below 0.5 ppm, which can significantly save the time of the phosgene synthesizing tower for purging the phosgene, greatly reduce the amount of nitrogen gas consumed, and improve the safety of the process operation.

The present invention relates to compositions containing at least 80% by weight, especially at least 90% by weight, based on the total weight of the composition, of at least one magnesium sulfate-urea compound selected from the compound of the formula (I) and mixtures of the compound of the formula (I) with the compound of the formula (II): [MgSO.sub.4.mCO(NH.sub.2).sub.2.nH.sub.2O] (I), [MgSO.sub.4.xCO(NH.sub.2).sub.2.yH.sub.2O] (II), in which m and x are each in the range from 0.9 to 1.1, n is in the range from 1.9 to 2.1 and y is in the range from 2.9 to 3.1, where the compositions, based on the total weight of the composition, contain less than 10% by weight of free MgSO.sub.4 in the form of the anhydrate or in the form of hydrates of magnesium sulfate and less than 10% by weight of unbound urea. The invention also relates to the production of the compositions and to the use thereof as fertilizers or fertilizer additive.