Abstract: A shell-and-tube type heat exchanger of the smallest possible length necessary for heat exchange is disclosed which is capable of obtaining uniform distribution of flow of a shell side fluid and substantially eliminating the structural restriction imposed on the shell side. This shell-and-tube type heat exchanger is provided with one annular conduit furnished with not less than two partitions concurrently serving as an expansion joint for introducing and discharging a shell side fluid and allowing the flow path for said shell side fluid to be separated into an introducing part and a discharging part and which comprises a place having no array of heat-transfer tubes in the flow path for said shell side fluid. It prevents the equipment from necessitating an unnecessary enlargement due to the structural restriction on the shell side and enables the shell side fluid to produce a uniform flow.

Abstract: This invention resides in providing a method for the prevention of possible polymerization of the easily polymerizable substance during the purification thereof by a column provided with (a) at least one tray directly fixed to a support ring with a bolt and a nut and/or (b) at least one tray fixed to a support ring with a vertical clamp or a distillation column provided in the lower part thereof with a splash collision plate.

Abstract: A shell-and-tube type heat exchanger of the smallest possible length necessary for heat exchange is disclosed which is capable of obtaining uniform distribution of flow of a shell side fluid and substantially eliminating the structural restriction imposed on the shell side. This shell-and-tube type heat exchanger is provided with one annular conduit furnished with not less than two partitions concurrently serving as an expansion joint for introducing and discharging a shell side fluid and allowing the flow path for said shell side fluid to be separated into an introducing part and a discharging part and which comprises a place having no array of heat-transfer tubes in the flow path for said shell side fluid. It prevents the equipment from necessitating an unnecessary enlargement due to the structural restriction on the shell side and enables the shell side fluid to produce a uniform flow.

Abstract: A shell-and-tube type heat exchanger of the smallest possible length necessary for heat exchange is disclosed which is capable of obtaining uniform distribution of flow of a shell side fluid and substantially eliminating the structural restriction imposed on the shell side. This shell-and-tube type heat exchanger is provided with one annular conduit furnished with not less than two partitions concurrently serving as an expansion joint for introducing and discharging a shell side fluid and allowing the flow path for said shell side fluid to be separated into an introducing part and a discharging part and which comprises a place having no array of heat-transfer tubes in the flow path for said shell side fluid. It prevents the equipment from necessitating an unnecessary enlargement due to the structural restriction on the shell side and enables the shell side fluid to produce a uniform flow.

Abstract: The present invention provides an industrially easy and economical method for purification of acrylic acid which enables to efficiently eliminate impurities from a crude acrylic acid containing aldehydes as the impurities while the formation of acrylic acid polymer is inhibited. The method for purification of acrylic acid includes the step of distilling a crude acrylic acid which is charged with an aldehyde treatment chemical, wherein the concentration ratio of furfural to acrolein by weight in the crude acrylic acid is adjusted so as to satisfy the following equation: (furfural concentration by weight)/(acrolein concentration by weight)?100.

Abstract: In an apparatus provided with a plate type heat exchanger as a heater and/or a cooler and operated to treat a gas containing an easily blocking substance, a method for preventing the plate type heat exchanger from being blocked is disclosed which is characterized by i) setting the width of a flow path on a plate of the plate type heat exchanger in the apparatus in a range of 6-25 mm and ii) setting the average flow rate of the gas passing the plate type heat exchanger in the apparatus per unit cross-sectional area of the flow path on the plate in the range of 3-15 m/s. In the exchange of heat of an easily blocking substance by the use of a plate type heat exchanger, a method for preventing the plate type heat exchanger from blockage is disclosed which has the plate type heat exchanger provided in the port for introducing a gas containing an easily blocking substance with a gas dispersion plate.

Abstract: A method for producing an organic acid and/or an organic acid ester which utilizes a steam system permitting stable production of an organic acid and/or an organic acid ester and realizing a high thermal efficiency constantly relative to the waste heat generated in the process of the production is provided. More particularly, this invention concerns a method for the production of an organic acid and/or an organic acid ester, wherein heat generated in the process for producing an organic acid and/or an organic acid ester is recovered in the form of steam, and the steam is used in any of the following forms: {circle around (1)} thermal energy, {circle around (2)} dynamic energy, and {circle around (3)} electrical energy in the process for producing an organic acid and/or an organic acid ester.

Abstract: A method for mixing a plurality of gases including forming a helical flow within a mixing vessel thereby allowing simplification of construction, avoiding pressure drop to the fullest possible extent, and expediting the mixture lest the volume of a gas within the explosion limits should increase, and an apparatus to be used for the method.

Abstract: A method for producing (meth)acrylic acid of high purity by repressing formation of a polymer possibly generated during the course of production is disclosed. The production is accomplished by returning the waste liquid generated at the step of the addition of aldehyde treating agents (d) to the step of the absorption (b) and/or the step of separation (c).

Abstract: In an apparatus provided with a plate type heat exchanger as a heater and/or a cooler and operated to treat a gas containing an easily blocking substance, a method for preventing the plate type heat exchanger from being blocked is disclosed which is characterized by i) setting the width of a flow path on a plate of the plate type heat exchanger in the apparatus in a range of 6-25 mm and ii) setting the average flow rate of the gas passing the plate type heat exchanger in the apparatus per unit cross-sectional area of the flow path on the plate in the range of 3-15 m/s. In the exchange of heat of an easily blocking substance by the use of a plate type heat exchanger, a method for preventing the plate type heat exchanger from blockage is disclosed which has the plate type heat exchanger provided in the port for introducing a gas containing an easily blocking substance with a gas dispersion plate.

Abstract: A shell-and-tube type heat exchanger of the smallest possible length necessary for heat exchange is disclosed which is capable of obtaining uniform distribution of flow of a shell side fluid and substantially eliminating the structural restriction imposed on the shell side. This shell-and-tube type heat exchanger is provided with one annular conduit furnished with not less than two partitions concurrently serving as an expansion joint for introducing and discharging a shell side fluid and allowing the flow path for said shell side fluid to be separated into an introducing part and a discharging part and which comprises a place having no array of heat-transfer tubes in the flow path for said shell side fluid. It prevents the equipment from necessitating an unnecessary enlargement due to the structural restriction on the shell side and enables the shell side fluid to produce a uniform flow.

Abstract: A method for producing an organic acid and/or an organic acid ester which utilizes a steam system permitting stable production of an organic acid and/or an organic acid ester and realizing a high thermal efficiency constantly relative to the waste heat generated in the process of the production is provided. More particularly, this invention concerns a method for the production of an organic acid and/or an organic acid ester, wherein heat generated in the process for producing an organic acid and/or an organic acid ester is recovered in the form of steam, and the steam is used in any of the following forms: {circle over (1)} thermal energy, {circle over (2)} dynamic energy, and {circle over (3)} electrical energy in the process for producing an organic acid and/or an organic acid ester.

Abstract: A heat exchanger for an easily polymerizing substance-containing gas provided with a shell possessed of a heat-exchanging gas inlet and a heat-exchanging gas outlet and a heat-exchanging part adapted to circulate fluid introduced from outside the shell between the gas inlet and said gas outlet, which heat exchanger is characterized by being provided with a gas distributing plate between the gas inlet and the heat-exchanging part. The heat exchanger is characterized by the gas distributing plate having a cross-sectional area in the range of 1.0-10.0 times the cross-section of the gas inlet. When an easily polymerizing substance-containing gas contacts a structure, the gas is condensed on the contact surface of the structure and suffered to generate a polymer.

Abstract: This invention resides in providing a method for the prevention of possible polymerization of the easily polymerizable substance during the purification thereof by a column provided with (a) at least one tray directly fixed to a support ring with a bolt and a nut and/or (b) at least one tray fixed to a support ring with a vertical clamp or a distillation column provided in the lower part thereof with a splash collision plate.

Abstract: A heat exchanger for an easily polymerizing substance-containing gas provided with a shell possessed of a heat-exchanging gas inlet and a heat-exchanging gas outlet and a heat-exchanging part adapted to circulate fluid introduced from outside the shell between the gas inlet and said gas outlet, which heat exchanger is characterized by being provided with a gas distributing plate between the gas inlet and the heat-exchanging part. The heat exchanger is characterized by the gas distributing plate having a cross-sectional area in the range of 1.0-10.0 times the cross-section of the gas inlet. When an easily polymerizing substance-containing gas contacts a structure, the gas is condensed on the contact surface of the structure and suffered to generate a polymer.

Abstract: A method for producing (meth) acrylic acid of high purity by repressing formation of a polymer possibly generated during the course of production is disclosed. The production is accomplished by returning the waste liquid generated at the step of the addition of aldehyde treating agents (d) to the step of the absorption (b) and/or the step of separation (c).

Abstract: The present invention provides an industrially easy and economical method for purification of acrylic acid which enables to efficiently eliminate impurities from a crude acrylic acid containing aldehydes as the impurities while the formation of acrylic acid polymer is inhibited.