Method and equipment for producing granular ammonium sulfate

Abstract

This product enables the stable production of large-particle granular ammonium sulfate. [Solution] A method for producing granular ammonium sulfate, comprising: reacting an ammonia-containing gas with an aqueous sulfuric acid solution to form an aqueous ammonium sulfate solution; introducing the aqueous ammonium sulfate solution into a crystallization vessel; precipitating ammonium sulfate in the crystallization vessel to form granular ammonium sulfate; and withdrawing a slurry containing the granular ammonium sulfate from the bottom of the crystallization vessel, wherein the solid-liquid ratio at multiple heights in the crystallization vessel is measured, and the amount of slurry withdrawn is controlled based on a corrected solid-liquid ratio calculated from the solid-liquid ratios measured at the multiple heights.

Claims

1. A method for producing granular ammonium sulfate, comprising: reacting an ammonia-containing gas with an aqueous sulfuric acid solution to form an aqueous ammonium sulfate solution; introducing the aqueous ammonium sulfate solution into a crystallization vessel; precipitating ammonium sulfate in the crystallization vessel to form granular ammonium sulfate; and withdrawing a slurry containing the granular ammonium sulfate from the bottom of the crystallization vessel, A method for producing granular ammonium sulfate, comprising measuring the solid-liquid ratio at multiple heights within the crystallization vessel and controlling the amount of slurry drawn based on a corrected solid-liquid ratio calculated from the solid-liquid ratios measured at the multiple heights.

2. The method for producing granular ammonium sulfate according to claim 1, wherein in calculating the corrected solid-liquid ratio, the corrected solid-liquid ratio is determined by correcting the solid-liquid ratio measured at the lowest position with a correction value obtained from the solid-liquid ratios measured at other heights.

3. In controlling the amount of extraction, the method for producing granular ammonium sulfate according to claim 1 or 2, wherein the target amount of extraction is determined from the corrected solid-liquid ratio, and the amount of extraction is adjusted so that the actual amount of extraction becomes the target amount of extraction.

4. A correspondence table is predetermined that associates the value of the corrected solid-liquid ratio with the value of the target withdrawal amount. The method for producing granular ammonium sulfate according to claim 3, wherein in determining the target extraction amount, the target extraction amount is determined from the corrected solid-liquid ratio calculated based on the correspondence table.

5. In the aforementioned correspondence table, the values ​​of the corrected solid-liquid ratio and the target extraction amount are associated such that the target extraction amount changes in steps in response to the change in the corrected solid-liquid ratio. The method for producing granular ammonium sulfate according to claim 4, wherein the range of the corrected solid-liquid ratio corresponding to one target extraction amount is 0.5% to 2%.

6. An absorption tower that reacts ammonia-containing gas with an aqueous sulfuric acid solution to produce an aqueous ammonium sulfate solution, A crystallizer for precipitating ammonium sulfate from the aforementioned ammonium sulfate aqueous solution to produce granular ammonium sulfate, An extraction means for drawing out the slurry containing the granular ammonium sulfate from the bottom of the crystallization container, A solid-liquid ratio measuring means for measuring the solid-liquid ratio at multiple heights within the crystallization vessel, A calculation means for calculating a corrected solid-liquid ratio from the solid-liquid ratio measured at the aforementioned multiple heights, A granular ammonium sulfate production apparatus comprising: an extraction amount control means for controlling the extraction amount of the slurry based on the corrected solid-liquid ratio; and a granular ammonium sulfate production apparatus.

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