Abstract: There is provided a method for handling high-viscosity substances discharged from a production process of acrylic acid or esters thereof by gas-phase catalytic oxidation, which method is improved such that upon transporting the high-viscosity substances in a molten state to a storage tank through a pipeline, the retention or clogging of the high-viscosity substances in the pipeline can be effectively prevented without adding a solvent thereto, resulting in smooth transportation thereof through the pipeline.

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: There is provided a process for producing (meth)acrylic acid and (meth)acrylic esters, which can be operated in a continuous and stable manner for a long period of time.

Abstract: There is provided a process for producing (meth)acrolein or (meth)acrylic acid which is capable of avoiding stoppage of operation of a plant for production thereof as a whole due to failure of an oxidation reaction step in the process and ensuring a continuous stable operation of the plant, and is excellent in economical aspects.

Abstract: There is provided a process for producing (meth)acrolein or (meth)acrylic acid which is capable of avoiding stoppage of operation of a plant for production thereof as a whole due to failure of a low-boiling fraction separation step in the process and ensuring a continuous stable operation of the plant, and has excellent economical aspects.

Abstract: The present invention provides a process for recovering liquid chemical products, in which the residual liquid chemical products remaining in respective handling devices in a chemical production facility can be efficiently and safely recovered therefrom without leakage thereof out of the system. In the process for recovering liquid chemical products in a chemical production facility according to the present invention, the chemical products are withdrawn from the handling devices through bottom discharge pipes (14), (15), (16) and (17) thereof, directly collected by the gravity thereof into a common inclined collection pipe (13) located at a position lower than the bottom discharge pipes and connected to the bottom discharge pipes, and then delivered by the gravity thereof through the inclined collection pipe (13) to a recovery tank (1) located at a position lower than the inclined collection pipe and connected to a lower end of the inclined collection pipe.

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: There is provided a method for preventing clogging in an apparatus for handling (meth)acrylic acid or esters thereof which is capable of inhibiting occurrence of clogging in nozzles or conduits connected to a gas-phase portion of the apparatus and ensuring a stable continuous operation of the apparatus for a long period of time. The method for preventing clogging in an apparatus for handling (meth)acrylic acid or esters thereof, comprises blowing a gas having a polymerization inhibiting action into a nozzle or conduit connected to a gas-phase portion of the apparatus, wherein said gas having a polymerization inhibiting action, which is blown into the nozzle or conduit, has a temperature not less than a temperature of the gas-phase portion.

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: There is provided an industrially useful process for producing (meth)acrylic esters which is improved so as to prolong a life of a strong acid cation exchange resin catalyst used therein. The process for producing a (meth)acrylic ester according to the present invention comprises a reaction step of esterifying (meth)acrylic acid with a C1 to C4 alcohol in the presence of a strong acid cation exchange resin catalyst to produce the (meth)acrylic ester; a recovery step of separating an unreacted (meth)acrylic acid from a reaction solution obtained in the reaction step; and a recycling step of recycling the thus recovered unreacted (meth)acrylic acid to the reaction step, solids contained in the recovered unreacted (meth)acrylic acid to be recycled to the reaction step being separated therefrom.

Abstract: There is provided a method for storing (meth)acrylic acid or (meth)acrylic esters in a storage tank for receiving or discharging the (meth)acrylic acid or (meth)acrylic esters, which is capable of storing the (meth)acrylic acid or (meth)acrylic esters for a long period of time. According to the method of the present invention, upon storing the (meth)acrylic acid or (meth)acrylic esters in the storage tank for receiving or discharging the (meth)acrylic acid or (meth)acrylic esters, a concentration of suspended particulate matters contained in a gas phase portion of the storage tank is controlled to not more than 0.01 mg/m3.

Abstract: There is provided a method for handling high-viscosity substances discharged from a production process of acrylic acid or esters thereof by gas-phase catalytic oxidation, which method is improved such that upon transporting the high-viscosity substances in a molten state to a storage tank through a pipeline, the retention or clogging of the high-viscosity substances in the pipeline can be effectively prevented without adding a solvent thereto, resulting in smooth transportation thereof through the pipeline.

Abstract: The present invention provides a method for handling a (meth)acrylic ester-containing solution in which the (meth)acrylic ester-containing solution is treated by at least one process selected from washing, neutralization and extraction, the said method being capable of ensuring a stable continuous operation of the treating system for a long period of time without deteriorating a liquid-liquid separation efficiency and a distillation efficiency in subsequent steps while inhibiting the formation of sludge, when waste water or a waste aqueous solution obtained by recovering effective ingredients from the (meth)acrylic ester-containing solution treated by said at least one process is recycled to the previous process and reused therein. The above waste water or waste aqueous solution is previously cooled to a temperature of 10 to 50° C. and then solids are removed therefrom prior to recycling the waste water or waste aqueous solution to the previous process and reusing the same therein.

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. Provided is a method for removing a metal from wastewater formed by subjecting at least a part of liquid waste to wet combustion treatment or wet oxidation treatment, said liquid waste resulting from an acrylic acid production process involving the steps of forming acrylic acid through catalytic vapor phase oxidation of at least one of propane, propylene, and acrolein, and purifying the acrylic acid through distillation, wherein the method comprises the steps of: (a) removing a solid content from the wastewater; (b) removing carbonate ions and carbonate salts from the treated liquid obtained by the step (a); and (c) removing a metal from the treated liquid from the step (b).

Abstract: The present invention provides a process for producing purified (meth)acrylic acid by subjecting crude (meth)acrylic acid containing maleic acids and aldehydes as impurities to distillation, the said process comprising, prior to the distillation, the following steps: (A) adding hydrazines to the crude (meth)acrylic acid at a temperature of not less than a melting point of acrylic acid and not more than 50° C. to react the maleic acids with the hydrazines; (B) heat-treating the reaction solution obtained in the above step (A) at a temperature of 60 to 90° C. to convert the reaction product into a substance soluble in the reaction solution; and (C) adding hydrazines to the thus heat-treated reaction solution obtained in the above step (B) at a temperature of not less than the melting point of acrylic acid and not more than 50° C. to react the aldehydes with the hydrazines, thereby producing a substance soluble in the reaction solution.

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 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: The present invention provides a process for recovering liquid chemical products, in which the residual liquid chemical products remaining in respective handling devices in a chemical production facility can be efficiently and safely recovered therefrom without leakage thereof out of the system. In the process for recovering liquid chemical products in a chemical production facility according to the present invention, the chemical products are withdrawn from the handling devices through bottom discharge pipes (14), (15), (16) and (17) thereof, directly collected by the gravity thereof into a common inclined collection pipe (13) located at a position lower than the bottom discharge pipes and connected to the bottom discharge pipes, and then delivered by the gravity thereof through the inclined collection pipe (13) to a recovery tank (1) located at a position lower than the inclined collection pipe and connected to a lower end of the inclined collection pipe.

Abstract: There is provided a process for purifying (meth)acrylic acid by efficiently removing transition metal components from crude (meth)acrylic acid containing the transition metal components as impurities. When the crude (meth)acrylic acid containing the transition metal components as impurities is contacted with the cation exchange resin to remove the transition metal components therefrom, water is previously added to the crude (meth)acrylic acid prior to contacting the crude (meth)acrylic acid with the cation exchange resin. In the preferred embodiment of the present invention, the transition metal component is manganese.

Abstract: An object of the present invention is to provide a method of vapor phase catalytic oxidation which is capable of: efficiently removing heat of reaction; preventing the formation of hot spots; and efficiently providing a desired product.