Compositions and methods are presented that selectively dissolve calcium from a variety of cementitious materials without dissolving or otherwise degrading calcium silica hydrate (CSH). Preferably, contemplated compositions comprise guanidine bisulfate hydrochloride, which can be prepared from a reaction of urea, hydrochloric acid, and sulfamic acid. Therefore, it is especially contemplated that the compositions contemplated herein are particularly suitable to clean or otherwise condition surfaces of cured concrete, Portland cement-based material, or an aggregate containing CSH.

Granulator (1), in particular for urea, comprising an active system for removal of encrustations from at least one wall (4) with a surface (14) exposed to the granulation process, wherein said system operates by imparting a pulsed deformation to said wall.

Granulator (1), in particular for urea, comprising an active system for removal of encrustations from at least one wall (4) with a surface (14) exposed to the granulation process, wherein said system operates by imparting a pulsed deformation to said wall.

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 is 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.

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 is 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.

Method for solidifying a chemical product (10) which is in melt form, comprising the following steps: subjecting a first stream (10a) of said chemical product to a prilling stage, with production of prills (12) of varying diameter; feeding said prills (12) to a screening device, which separates them according to their diameter into at least a first fraction (13) and a second fraction (14), the average diameter of the prills of said first fraction (13) being smaller than the average diameter of the prills of said second fraction (14); subjecting a second stream (10b) of said chemical product and the first fraction (13) of prills to a granulation stage, with the production of granules (16).

Method for solidifying a chemical product (10) which is in melt form, comprising the following steps: subjecting a first stream (10a) of said chemical product to a prilling stage, with production of prills (12) of varying diameter; feeding said prills (12) to a screening device, which separates them according to their diameter into at least a first fraction (13) and a second fraction (14), the average diameter of the prills of said first fraction (13) being smaller than the average diameter of the prills of said second fraction (14); subjecting a second stream (10b) of said chemical product and the first fraction (13) of prills to a granulation stage, with the production of granules (16).

A process for the production of formaldehyde-stabilised urea is described comprising the steps of: (a) generating a synthesis gas; (b) subjecting the synthesis gas to one or more stages of water-gas shift in one or more water-gas shift reactors to form a shifted gas; (c) cooling the shifted gas to below the dew point and recovering condensate to form a dried shifted gas; (d) recovering carbon dioxide from the dried shifted gas in a carbon dioxide removal unit to form a carbon dioxide-depleted synthesis gas; (e) synthesising methanol from the carbon dioxide-depleted synthesis gas in a methanol synthesis unit and recovering the methanol and a methanol synthesis off-gas; (f) subjecting at least a portion of the recovered methanol to oxidation with air to form formaldehyde in a stabiliser production unit; (g) subjecting the methanol synthesis off-gas to methanation in a methanation reactor containing a methanation catalyst to form an ammonia synthesis gas; (h) synthesising ammonia from the ammonia synthesis gas in an ammonia production unit and recovering the ammonia; (i) reacting a portion of the ammonia and at least a portion of the recovered carbon dioxide stream in a urea production unit to form a urea stream; and (j) stabilising the urea by mixing the urea stream and a stabiliser prepared using the formaldehyde produced in the stabiliser production unit, wherein the carbon dioxide removal unit operates by means of absorption using a liquid absorbent and comprises an absorbent regeneration unit, wherein the process includes recovering a carbon dioxide-containing gas stream from the absorbent regeneration unit, compressing at least a portion of the recovered carbon dioxide-containing gas stream to form a compressed carbon dioxide-containing gas stream and passing the compressed carbon dioxide-containing gas stream to the methanol synthesis unit.

Method and fluidized bed reactor for the production of granules, such as granules of urea or ammonium nitrate. The reactor comprises at least one granulation compartment with air inlets, and an air moving device downstream the granulation compartment, e.g., downstream one or more scrubbers. The air moving device is configured to draw air through said one or more air inlets into the granulation compartment.

Method and fluidized bed reactor for the production of granules, such as granules of urea or ammonium nitrate. The reactor comprises at least one granulation compartment with air inlets, and an air moving device downstream the granulation compartment, e.g., downstream one or more scrubbers. The air moving device is configured to draw air through said one or more air inlets into the granulation compartment.