Mitsubishi Chemical Corporation

Masayasu Goriki

Shuhei Yada

Yasushi Ogawa

Yoshiro Suzuki

Kimikatsu Jinno

Hirochika Hosaka

Kenji Takasaki

Yoshihiro Shimizu

A subject for the invention is to provide a method of transferring a polymerizable liquid by which the polymerizable liquid can be stably transferred without arousing any mechanical-seal trouble over long. The method of transferring a polymerizable liquid utilizes a pump which has a mechanical seal having seal faces and has a flushing liquid line for supplying a flushing liquid to a flushing liquid introduction opening of the mechanical seal, wherein the flushing liquid line is equipped with a strainer, a device for adding a polymerization inhibitor, or a flushing liquid cooler.

Method of transferring polymerizable liquid and apparatus for transfer

In the stopping and starting operations of a distillation column used for producing (meth)acrylic acids according to the present invention, upon stopping the operation of the distillation column, the heating of a reboiler attached thereto is interrupted and then the reboiler is rapidly cooled; and/or upon starting the operation of the distillation column for production of the (meth)acrylic acids, an inner wall surface of the distillation column is heated to a temperature higher than a condensation temperature of the (meth)acrylic acids and the operation of the distillation column is started under the heated condition. According to the present invention, it is possible to early and safely stop the operation of the distillation column while preventing the occurrence of polymerization within the distillation column, and stably perform an operation for distillation of acrylic monomers for a long period of time.

Process for producing (meth)acrylic acids and process for distilling the same

A multitube reactor, wherein tubes having smaller tolerance between a nominal size and actual sizes are used as reaction tubes to stably perform a high yield reaction for a long period, a catalyst is filled into the reaction tubes so that the catalyst layer peak temperature portions of the reaction tubes are not overlapped with the connection sites thereof with baffles to effectively prevent hot spots from occurring and stably perform a reaction for a long period without the clogging of the reaction tubes, a heat medium and raw material gas are allowed to flow in the direction of a countercurrent and a specified type of catalyst is filled into the reaction tubes so that activity is increased from the inlet of the raw material gas to the outlet thereof to prevent the autooxidation of products so as to prevent equipment from being damaged due to the reaction, and, at the time of starting, gas with a temperature of 100 to 400&#xb0; C. is led to the outside of the reaction tubes to increase the temperature of the reaction tubes and, a heat medium, which is solid at the room temperature, is heated to circulate to the outside of the reaction tubes to efficiently start up the reactor without affecting the activity of the catalyst.

Multitube reactor, vapor phase catalytic oxidation method using the multitube reactor, and start up method applied to the multitube reactor

The storage tank of the invention for an easily polymerizable compound is a storage tank having an acceptance piping and a delivery piping and is characterized by having a circulation line which directly connects the acceptance piping to the delivery piping or having circulation lines which respectively connect the acceptance piping to the storage tank and the storage tank to the delivery piping; the method of storing of the invention is characterized by storing an easily polymerizable compound in the storage tank while circulating the compound in the storage tank through the circulation line(s); the method of pipe jointing and apparatus therefor of the invention are a method of jointing pipes fitted to a handling apparatus in a production apparatus, storage apparatus, or the like for the purpose of transporting a corrosive liquid, the method being characterized in that the pipes are jointed with flanges, bolts, and nuts made of a material having resistance to corrosion by the corrosive liquid; the process for (meth)acrylic acid compound production of the invention is a process for producing and/or purifying a (meth)acrylic acid compound, and is characterized in that the temperature of a purified (meth)acrylic acid compound obtained which is being supplied to a storage tank is regulated so as to be not higher than the temperature of the purified (meth)acrylic acid compound residing in the storage tank; and the process of the invention for producing an easily polymerizable compound which is a (meth)acrylic acid compound is characterized in that the temperature of a (meth)acrylic acid compound-containing liquid which has been discharged as an off-specification product and is being supplied to a storage tank is regulated so as to be not higher than the temperature of the off-specification liquid stored in the storage tank.

Storage tank for easily polymerizable compound and method of storage

A storage tank for an easily polymerizable compound has acceptance piping and delivery piping with a circulation line directly connecting the acceptance piping to the delivery piping or with circulation lines respectively connecting the acceptance piping to the storage tank and the storage tank to the delivery piping. A method of storing an easily polymerizable compound in the storage tank includes circulating the compound in the storage tank through the circulation line(s), where the compound can be (meth)acrylic acid being produced and/or purified with the temperature of purified (meth)acrylic acid being supplied to or removed from the storage tank being regulated to not be higher than the temperature thereof in the tank. A method of joining pipes for-transporting a corrosive liquid using flanges, bolts, and nuts made of a material having resistance to corrosion by the corrosive liquid.

A subject for the invention is to stably supply an ambient gas having a given composition to a production apparatus or storage apparatus for a compound necessitating strict ambient gas regulation during the production, storage, or handling thereof, such as (meth)acrylic acid or an ester thereof which are easily polymerizable and form an explosive composition at ordinary temperature, in a manner not influenced by fluctuations in the amount of the gas used. In the invention, the pressure of the gas-phase part in a tank () or mixing vessel () is detected with a manometer (P-) or (P-), and a dry air/nitrogen mixed gas is supplied to the tank () or mixing vessel () in an amount compensating for the gas consumption. The pressure in a mixed-gas supply piping () is detected with a manometer (P-), and a dry air/nitrogen mixed gas is supplied to the piping () in an amount compensating for the gas consumption. The degree of opening of a flow control valve (V-) for nitrogen is regulated so as to be in proportion to the degree of opening of a flow control valve (V-) for dry air. Thus, a mixed gas having a given oxygen concentration is supplied.

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Mie, Japan

Masayasu Goriki