Process for producing (meth)acrylic acid
View Patent ↗Clogging of a distillation column by polymerization caused by a change of the production rate of (meth)acrylic acid, is prevented to carry out a stabilized operation over a long period. A process for producing (meth)acrylic acid, which includes a purification step wherein a (meth)acrylic acid-containing material to be purified is supplied to and distilled by a distillation column, wherein during a cut operation in which the production rate of (meth)acrylic acid is reduced by α% relative to the production rate of (meth)acrylic acid during the ordinary operation, the liquid/gas flow rate in the distillation column is adjusted to be at least (100−α/2)% of the liquid/gas flow rate during the ordinary operation.
1. A process for producing (meth)acrylic acid, which comprises purifying a (meth)acrylic acid-containing material to be purified, wherein said purifying comprises distilling said (meth)acrylic acid containing material in a distillation column, wherein during a cut operation in which a production rate of (meth)acrylic acid is reduced by α% relative to a production rate of (meth)acrylic acid prior to said cut operation, a liquid/gas flow rate in the distillation column is adjusted to be at least (100−α/2)% of the liquid gas flow rate prior to said cut operation,
wherein a fluctuation margin of a heat load on a reboiler of the distillation column prior to said cut operation is a fluctuation margin such that proportions X B and X A of the differences between an average value R 5 of a heat load during optional 5 minutes and an average value R B of a heat load during one hour before the 5 minutes and between R 5 and an average value R A of a heat load for one hour after the 5 minutes, as calculated by the following formulae, are at most 10%:
X B =(| R B −R 5 |/R B )×100
X A =(| R A −R 5 |/R A )×100.
2. The process for producing (meth)acrylic acid according to claim 1 , wherein a liquid withdrawn from a top and/or the bottom of the distillation column is recycled to the distillation column on an upstream side thereof.
3. The process for producing (meth)acrylic acid according to claim 1 , wherein during the cut operation in which the production rate of (meth)acrylic acid is reduced by α%, the liquid/gas flow rate in the distillation column is adjusted to be at least (100−α/3)% of the liquid/gas flow rate prior to said cut operation.
4. The process for producing (meth)acrylic acid according to claim 1 , wherein when an amount of the material to be purified, supplied to the distillation column, an amount of a liquid refluxed to the distillation column, or a heat load on a reboiler side of the distillation column, is changed, the change per hour is at most ±5%.
5. The process for producing (meth)acrylic acid according to claim 1 , wherein α is at most 30.
6. The process for producing (meth)acrylic acid according to claim 2 , wherein α is at most 30.
7. The process for producing (meth)acrylic acid according to claim 3 , wherein α is at most 30.
8. The process for producing (meth)acrylic acid according to claim 4 , wherein α is at most 30.
9. The process for producing (meth)acrylic acid according to claim 2 , wherein during the cut operation in which the production rate of (meth)acrylic acid is reduced by α%, the liquid/gas flow rate in the distillation column is adjusted to be at least (100−α/3)% of the liquid/gas flow rate during the ordinary operation.
10. The process for producing (meth)acrylic acid according to claim 4 , wherein during the cut operation in which the production rate of (meth)acrylic acid is reduced by α%, the liquid/gas flow rate in the distillation column is adjusted to be at least (100−α/3)% of the liquid/gas flow rate during the ordinary operation.
11. The process for producing (meth)acrylic acid according to claim 5 , wherein during the cut operation in which the production rate of (meth)acrylic acid is reduced by α%, the liquid/gas flow rate in the distillation column is adjusted to be at least (100−α/3)% of the liquid/gas flow rate during the ordinary operation.
12. The process for producing (meth)acrylic acid according to claim 2 , wherein when an amount of the material to be purified, supplied to the distillation column, an amount of a liquid refluxed to the distillation column, or a heat load on a reboiler side of the distillation column, is changed, the change per hour is at most ±5%.
13. The process for producing (meth)acrylic acid according to claim 3 , wherein when an amount of the material to be purified, supplied to the distillation column, an amount of a liquid refluxed to the distillation column, or a heat load on a reboiler side of the distillation column, is changed, the change per hour is at most ±5%.
14. The process for producing (meth)acrylic acid according to claim 1 , wherein when an amount of the material to be purified, supplied to the distillation column, an amount of a liquid refluxed to the distillation column, or a heat load on a reboiler side of the distillation column, is changed, the change per hour is at most ±5%.