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公开(公告)号：US20190233361A1
公开(公告)日：2019-08-01
申请号：US16331851
申请日：2017-08-28
摘要： A method for producing high-purity terephthalic acid, comprising following steps (a) to (e):(a) a step of obtaining a crude terephthalic acid crystal by liquid-phase oxidizing a p-phenylene compound, (b) a step of dissolving the crude terephthalic acid crystal in water and then subjecting to catalytic hydrogenation treatment, (c) a step of depressurizing and cooling a reaction liquid after the catalytic hydrogenation treatment in stages with two or more stages of crystallization vessels, to crystallize terephthalic acid to obtain a terephthalic acid slurry, (d) a step of introducing the terephthalic acid slurry into an upper portion of a mother liquor replacement tower, bringing the terephthalic acid crystal into contact with an upward flow of replacement water introduced from a tower lower compartment of the mother liquor replacement tower while making the terephthalic acid crystal settled down in the tower, and withdrawing the terephthalic acid crystal as slurry with the replacement water from the tower lower compartment, and (e) a step of subjecting the slurry withdrawn from the tower lower compartment to solid-liquid separation into water and the terephthalic acid crystal, and drying the separated terephthalic acid crystal, wherein when a throughput of the crystal subjected to the catalytic hydrogenation treatment is Q [ton/hr], and residence time in a first-stage crystallization vessel of the two or more stages of crystallization vessels is T1 [hr], and a cross-sectional area of the mother liquor replacement tower is A [m2], following conditions (1) to (3): 0.07≤T1≤0.5 (1) 0.3≤A/Q≤0.8 (2) 0.035≤T1×A/Q≤0.25 (3) are all satisfied. In the method for producing high-purity terephthalic acid, mother liquor replacement is efficiently performed, the heating load during the step of drying the purified terephthalic acid cake after the solid-liquid separation is small, and terephthalic acid that exhibits good behavior as a starting material of polyester can be produced.
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公开(公告)号：US20190169109A1
公开(公告)日：2019-06-06
申请号：US16088226
申请日：2017-03-07
CPC分类号： C07C51/47 , C07B2200/13 , C07C51/43 , C07C63/26
摘要： A method of terephthalic acid production in which slurry of crude terephthalic acid obtained through liquid-phase oxidation of a p-phenylene compound or a terephthalic acid slurry resulting from catalytic hydrogenation of the crude terephthalic acid is introduced into an upper part of a dispersion medium replacement tower while a second dispersion medium for replacement is introduced from a lower part of the dispersion medium replacement tower to perform dispersion medium replacement. The method is capable of enabling the dispersion medium replacement tower to continue stable operation while maintaining an extremely high efficiency of dispersion medium replacement.
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公开(公告)号：US20180230078A1
公开(公告)日：2018-08-16
申请号：US15745738
申请日：2016-07-21
发明人： Goh NAKAMURA , Hideaki FUJITA , Kotaro MURAKAMI
IPC分类号： C07C51/43 , C07C51/265
CPC分类号： C07C51/43 , C07C51/265 , C07C51/487 , C07C63/26
摘要： A method for producing high-purity terephthalic acid, comprising following steps (a) to (c): the step (a); obtaining crude terephthalic acid crystal by liquid phase-oxidizing a p-phenylene compound; the step (b); obtaining a terephthalic acid crystal slurry by a catalytic hydrogenation treatment of the crude terephthalic acid crystal; and the step (c); introducing the terephthalic acid crystal slurry into an upper portion of a mother liquor replacement tower, and bringing the slurry into contact with an upward flow of replacement water introduced from a bottom portion of the mother liquor replacement tower while making the terephthalic acid crystal settled down in the tower, and extracting the terephthalic acid crystal as a slurry with the replacement water from the tower bottom portion, wherein (1) a stirring blade unit is disposed in a slurry layer in the bottom portion of the mother liquor replacement tower, and fluidity of the slurry layer is maintained by rotating the stirring blade unit in such a way that stirring power is 0.1 to 1.0 kWh/m3 per unit volume of the slurry layer, and (2) the replacement water is fed through the replacement water feed opening provided in the stirring blade unit.
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