Abstract: A first and second aspect of the invention relate to a process for producing a (meth)acrylic acid compound and a process for producing a (meth)acrylic ester, respectively. In particular, the second aspect of the invention relates to a process for (meth)acrylic ester production which includes a step in which by-products of a (meth)acrylic ester-yielding reaction are decomposed to recover a (meth)acrylic ester. A third aspect of the invention relates to a method of decomposing by-products of (meth)acrylic ester production in order to recover (meth)acrylic acid, a (meth)acrylic ester, and an alcohol through the decomposition of the by-products of (meth)acrylic ester production. A fourth and fifth aspect of the invention relate to a method of decomposing by-products of (meth)acrylic acid compound production in order to recover (meth)acrylic acid, a (meth)acrylic ester, and an alcohol through the decomposition of by-products of (meth)acrylic acid production and by-products of (meth)acrylic ester production.

Abstract: 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 fo

Abstract: 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.

Abstract: An object of the present invention is to provide a method for vapor phase catalytic oxidation which is almost free of variations in reaction states in respective reaction tubes of the fixed bed multi-tube heat-exchanger type reactor.

Abstract: (1) In a gas-phase catalytic oxidation process for conducting gas-phase catalytic oxidation reaction using a fixed bed multipipe type reactor having reaction tubes filled with a catalyst while feeding a reaction raw gas thereinto, the catalyst is filled in each of the reaction tubes of the fixed bed multipipe type reactor to form two or more catalyst layers having different catalytic activities from each other in a direction of the oxidation reaction, and the catalyst layer disposed nearest to a reaction raw gas inlet of the reaction tube has a higher catalytic activity than that of the next catalyst layer adjacent thereto, or (2) in a process for producing (meth)acrolein or (meth)acrylic acid by subjecting a raw material of the (meth)acrolein or (meth)acrylic acid, and molecular oxygen or a molecular oxygen-containing gas to gas-phase catalytic oxidation reaction using a fixed bed multipipe type reactor having two or more catalyst layers in an axial direction of each of reaction tubes provided in the reactor

Abstract: 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° C.

Abstract: A multiple-projection system capable of stably observing high-definition and high quality images and capable of corresponding to the switching of the routes promptly, without irregular color etc. and without performing calibration at each switching of routes, is provided. A multiple-projection system for projecting one image on a screen 5 by two or more projectors 4, comprises a plurality of switchable routes for observing an image projection, a compensation data preservation sections 21a, 21b for storing compensation data to correct output characteristic of respective projectors 4 corresponding to respective routes, and an image processing section 22 for correcting and processing the input image signal based on the compensation data stored in the compensation data preserving section corresponding to the route used.

Abstract: In a nozzle or a pipe for connecting a measuring device which monitors a process state of (meth)acrylic acid and esters thereof and a gas-phase part and/or a liquid-phase part of an apparatus for handling (meth)acrylic acid and esters thereof, a gas comprising at least one of an inert gas, oxygen, and a gas having an effect of inhibiting polymerization is blown into the nozzle and/or the pipe connected to the gas-phase part of the apparatus at a flow rate of 0.03 to 1 m/second and a liquid medium is blown into the nozzle and/or the pipe connected to the liquid-phase part of the apparatus at a flow rate of 0.03 to 1 m/second to prevent a clogging of the apparatus for handling (meth)acrylic acid and esters thereof. According to the method, stable and efficient operation of the apparatus for handling (meth)acrylic acid and the like and a decrease of a cost for production or storage of (meth)acrylic acid can be achieved.

Abstract: In an apparatus capable of distilling and refining an easily polymerizable substance, piping is performed so that when a strainer in action is switched to a backup strainer, the strainer can be switched after removing the air in the backup strainer to replace the air in the backup strainer to a discharge liquid of a pump. According to the apparatus, switching the strainers installed on the upstream side of the pump for extracting a liquid of a vacuum distillation column which distills and refines the easily polymerizable substance can be performed with no trouble in the operation of the distillation column. When the apparatus comprises a means measuring a differential pressure between the upstream side and the downstream side of the strainer in action, the two or more strainers installed in parallel can be switched at proper times and the easily polymerizable substance can be produced efficiently.

Abstract: In a distillation apparatus, a production process and a purification method of readily polymerizable compounds, a problem of the invention is to solve a serious plugging problem in a large-sized distillation column as in the commercial equipment and to provide an apparatus and a method for distilling and purifying a readily polymerizable compound stably over a long period of time.

Abstract: In a process for producing (meth)acrylic acid comprising contacting a reaction gas containing (meth)acrylic acid obtained by gas-phase catalytic oxidation with an absorbent solvent to prepare a (meth)acrylic acid solution; and introducing the (meth)acrylic acid solution into a distillation column to purify (meth)acrylic acid, after a dissolved oxygen concentration in the (meth)acrylic acid solution to be introduced into the distillation column is adjusted to not less than 12 ppm by weight, the (meth)acrylic acid solution is fed to the distillation column. In addition, upon an azeotropic dehydration distillation step, a phenol-based polymerization inhibitor is fed to an azeotropic dehydration distillation column from a position not lower than a raw material feed stage thereof, and a copper-based polymerization inhibitor is fed to the azeotropic dehydration distillation column from a position lower than the raw material feed stage.

Abstract: A problem of the invention is to provide a method of decomposing a Michael addition reaction product formed as a by-product in the production step of a (meth)acrylic ester and recovering (meth)acrylic acid, a (meth)acrylic ester and an alcohol, in which the formation of an olefin as a by-product can be suppressed.

Abstract: 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 &agr;% 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−&agr;/2)% of the liquid/gas flow rate during the ordinary operation.

Abstract: An object of the present invention is to provide a method for efficiently removing a metal from wastewater formed by subjecting the liquid waste to wet combustion treatment or wet oxidation treatment, said liquid waste resulting from an acrylic acid production process.

Abstract: An object of the invention is to provide a process in which Michael addition reaction products generated as by-products in a (meth)acrylic acid production step are pyrolyzed to enable high-purity (meth)acrylic acid to be recovered at a high recovery and troubles such as clogging in production steps are prevented.

Abstract: A process for producing (meth)acrylic acid or (meth)acrylic acid esters, which comprises a reaction step comprising vapor phase catalytic oxidation of propylene, propane or isobutylene and, if necessary, a reaction step comprising an esterification step, characterized in that at the time when a high boiling mixture (hereinafter referred to as a high boiling material) containing a Michael addition product, is decomposed in a decomposition reactor to recover (meth)acrylic acids, while forcibly imparting a liquid flow in the circumferential direction to a liquid reaction residue in the decomposition reactor, the liquid reaction residue is discharged. In a process for recovering a valuable substance by thermally decomposing the high boiling material containing the Michael addition product of (meth)acrylic acids, it is possible to transfer the decomposition residue from the decomposition reactor to the storage tank without clogging, whereby a long-term continuous operation is possible.

Abstract: A method for transporting an easily polymerizable liquid by a pipeline having branches, wherein among pipelines branched at a branch point, one pipeline which may not be used over a long period of time, is provided with a valve to close the pipeline, within 500 mm from the branch point.

Abstract: In an acrylic acid production process which comprises the step of producing acrylic acid by catalytic vapor-phase oxidation of propane, propylene, and/or acrolein; and purifying the acrylic acid produced in the step of producing with distillation in the presence of the polymerization inhibitor for preventing polymerization of the acrylic acid, a viscosity at 20° C. of the bottoms which comprises the polymerization inhibitor, discharged in the step of purifying, is adjusted to 2 Pa.s (2,000 cP) or less and the polymerization inhibitor is extracted using an aqueous medium.

Abstract: A method for purifying a crude (meth)acrylic acid obtained by a vapor phase catalytic oxidation method, characterized in that the crude (meth)acrylic acid having most parts of water and acetic acid removed therefrom, is fed to and distilled in a first distillation column of a purification system comprising first to third three distillation columns, the top fraction from the first distillation column is fed to and distilled in the second distillation column, the resulting top fraction is recovered as a high purity (meth)acrylic acid product, the bottoms from the first and second distillation columns are fed to and distilled in the third distillation column, and the resulting top fraction is fed to the first distillation column.

Abstract: A method for collecting acrylic acid comprising the step of collecting acrylic acid using an aqueous medium from a reaction gas comprising acrylic acid obtained by catalytic vapor-phase oxidation of propane, propylene, and/or acrolein, the step being conducted so as to satisfy the following formula (1) wherein A represents a weight fraction of acrylic acid to all condensable ingredients in the reaction gas before collecting acrylic acid and B represents a weight fraction of acrylic acid in bottoms of a collection device used in the step of collecting. According to the method, acrylic acid can be efficiently collected from the reaction gas comprising acrylic acid obtained by catalytic vapor-phase oxidation.