Nippon Shokubai Co., Ltd.

Kenji Sanada

Yukihiro Matsumoto

Kazuhiko Sakamoto

Takeshi Nishimura

Harunori Hirao

Sei Nakahara

Masatoshi Ueoka

Masakatsu Mori

Noriaki Mizutani

A method for the production of acrylic acid comprises (i) a step for introducing a polymerization inhibitor to a stage other than a stage for supplying a raw material and a stage for supplying a reflux of said distilling column or (ii) a step for supplying the acrylic acid recovered by thermally decomposing said oligomer to said stage for dehydration. Thus, the present invention enjoys effective utilization of acrylic acid and exalts the efficiency of production.

Method for production of acrylic acid

It is an object of the present invention to provide a process for producing aliphatic carboxylic acid, which can stabilize operation of a distillation column upon production of aliphatic carboxylic acid by reducing a water content in an aqueous aliphatic carboxylic acid solution by a distillation column, and can shorten a time during the non-steady state such as at starting up of distillation column operation. The present invention is directed to a process for producing aliphatic carboxylic acid, which comprises an azeotropic distillation step of supplying an aqueous aliphatic carboxylic acid solution and an azeotropic solvent to an azeotropic distillation column to perform distillation, separating an azeotrope containing the azeotropic solvent and water as a distillate, and recovering aliphatic carboxylic acid with a reduced water content as bottom liquid, characterized in that a target value of an amount of the azeotropic solvent to be supplied is set depending on an amount of water in the aqueous aliphatic carboxylic acid solution supplied to the azeotropic distillation column, and the amount of the azeotropic solvent to be supplied is controlled at the target value.

Process for producing aliphatic carboxylic acid

A perforated tray without downcomer having only a small deviation between the opening ratio based on the diameter of a column and the actual opening ratio and a perforated tray column without downcomer formed by disposing such perforated trays without downcomer are provided. The perforated trays without downcomer are characterized by having a ratio of (A)/(B) in the range of 1.1-1.5, wherein A denotes the opening ratio found from the standard pitch between centers of holes and (B) denotes the opening ratio based on the diameter of a column.

Perforated tray column without downcomer

This invention is providing a method for efficient treatment of the waste material from a process for production of acrylic acid and an acrylic ester. This is a method for the disposal of waste material, which at least one waste material selected from the group consisting of waste oil, waste water, and waste gas emitted from a process for production of acrylic acid is/are purified with at least one waste material selected from the group consisting of waste oil, waste water, and waste gas emitted from a process for production of an acrylic ester jointly. The efficiency of the treatment is enhanced by simultaneously treating the waste material.

Method for disposal of waste from acrylic acid process and acrylic ester process

A method is disclosed which produces acrylic acid in a high yield as maintaining the conditions for purifying acrylic acid in constant ranges and preventing the acrylic acid from polymerization. By using single a single reactor, propylene concentration adjusting in the range of 7&#x2013;15 vol. % and water concentration adjusting in the range of 0&#x2013;10 vol. % are introduced thereinto thereby obtaining an acrylic acid-containing gas. Then the gas is introduced to an acrylic acid absorption column to adjust water concentration in the range of 1&#x2013;45 wt. %, thereby preventing from polymerization.

A method for managing the operation of an apparatus for the reaction of gas phase partial oxidation of an unsaturated hydrocarbon with a molecular oxygen-containing gas for the purpose of omitting wasteful emergency stop of the operation and ensuring execution of necessary emergency measure and a method for producing (meth) acrylic acid by utilizing the method mentioned above are provided. The operation of the apparatus is brought to emergency stop exclusively when thee values of concentrations of various gases obtained by calculation from the flow rates of the gases being introduced at the inlet port of the reactor and the measured values obtained by analysis with gas analyzing instruments both deviate from the ranges of the present values.

Method for managing operation of gas phase reaction apparatus

The present invention provides an apparatus for producing (meth)acrylic acid and a process for producing (meth)acrylic acid with this apparatus wherein the apparatus enables the production of (meth)acrylic acid stably for a long period of time by effectively inhibiting the polymerization of (meth)acrylic acid in its production process (for example, in a reboiler). At least a part of the apparatus is made of a nickel-chromium-iron alloy with a molybdenum content of 3 to 20 mass %, but not including 3 mass %, or with a molybdenum content of 1 to 4 mass % and a copper content of 0.5 to 7 mass %.

Apparatus and process for producing (meth)acrylic acid

A method for distilling a raw material liquid containing (meth)acrylic acid substantially free from azeotropic solvents, collected with a collection agent from a mixed gas obtained by gas phase catalytic oxidation reactions which includes feeding to a distillation column the raw material liquid which temperature is substantially equal to that of the entrance place in the column.

Method for distilling (meth) acrylic acid solution

A distillation apparatus is provided with a distillation tower, a reboiler, a bottom outflow pipe for drawing a liquid from the bottom of the distillation tower, and a pot provided between the bottom of the distillation tower and the bottom outflow pipe. A part of the drawn liquid is discharged to the outside of the distillation apparatus while the rest is flowed to the reboiler. The pot has a cross-sectional area smaller than a cross-sectional area of the distillation tower and larger than a cross-sectional area of the bottom outflow pipe.

Distillation apparatus and distilling method

In a packed column handling an easily polymerizing substance, the packing with which the column is stuffed is subjected to a water-repelling treatment or a wetting treatment to prevent the easily polymerizing substance in the packed column from polymerizing. By preventing the occurrence of a polymer, it is made possible to ensure continuous production of an easily polymerizing substance-containing solution and decrease the content of the easily polymerizing substance in the product and consequently improve the quality of the product.

Method for preventing easily polymerizing substance from polymerization and method for production of (meth) acrylic acid or ester thereof

The present invention provides an apparatus for producing (meth)acrylic acid and a process for producing (meth)acrylic acid with this apparatus wherein the apparatus enables to produce (meth)acrylic acid stably for a long period of time by effectively inhibiting the polymerization of (meth)acrylic acid in its production process (for example, in a reboiler). At least a part of the apparatus is made of a nickel-chromium-iron alloy with a molybdenum content of 3 to 20 mass %, but not including 3 mass %, or with a molybdenum content of 1 to 4 mass % and a copper content of 0.5 to 7 mass %.

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Himeji, Japan

Kenji Sanada