Abstract: Provided is a method for preparing steam, comprising: making a process waste heat fluid supplied from a plurality of waste heat sources flow into each of refrigerant evaporators having numbers corresponding to plurality of waste heat sources to vaporize a refrigerant through heat exchange; joining vaporized refrigerant streams from each of refrigerant evaporators to one integrated pipe; compressing refrigerant stream joined to integrated pipe in a refrigerant compressor; heat exchanging compressed refrigerant stream with water in a refrigerant condenser to prepare a condensed refrigerant stream and steam; and decompressing the condensed refrigerant stream by passing condensed refrigerant stream through a refrigerant expansion valve, followed by branching and circulating the condensed refrigerant stream to each of plurality of refrigerant evaporators, and further including transferring and compressing steam flowing out of refrigerant condenser to a steam compressor, and a system for recovering waste heat.

Abstract: Provided is a method for recovering a conjugated diene-based monomer including: supplying a feed stream including a conjugated diene-based monomer to a condensation part and performing condensation to obtain a stream including a condensed conjugated diene-based monomer and a stream including an uncondensed conjugated diene-based monomer; recovering a conjugated diene-based monomer from the stream including a condensed conjugated diene-based monomer, and supplying the stream including an uncondensed conjugated diene-based monomer to a first absorption tower and bringing it into contact with a sorbent to obtain an absorbed solution in which the conjugated diene-based monomer is absorbed into the sorbent; and supplying the absorbed solution to a stripping column to separate the absorbed solution into the sorbent and the conjugated diene-based monomer, circulating a lower discharge stream from the stripping column including the separated sorbent to the first absorption tower, and circulating an upper discharge st

Abstract: Provided is a wastewater purification method, the method including: supplying a first mixed stream, in which an acid component and wastewater including water, a nitrile-based monomer, and ammonia are mixed, to a first column; recovering the nitrile-based monomer from an upper discharge stream from the first column; supplying a second mixed stream, in which a lower discharge stream from the first column and a base component are mixed, to a second column; and recovering the ammonia from an upper discharge stream from the second column and separating purified wastewater.

Abstract: A continuous preparation system of a conjugated diene-based polymer having improved rolling resistance properties is provided. By utilizing the continuous preparation system a polymerization conversion ratio at an initial stage of polymerization is easy to control, long time operation is possible and productivity is excellent.

Abstract: A method for purifying of waste water includes: supplying a mixed stream, in which wastewater including water, a nitrile-based monomer, and ammonia and an acid component are mixed, to a first column; condensing an upper discharge stream of the first column, supplying the condensed stream to a decanter to separate the stream into a water layer and an organic layer, and supplying components of the organic layer to a second column; and separating a by-product from a lower discharge stream of the second column, and recovering the nitrile-based monomer from an upper discharge stream of the second column.

Abstract: Provided is a wastewater purification method, the method including: supplying a first mixed stream, in which an acid component and wastewater including water, a nitrile-based monomer, and ammonia are mixed, to a first column; recovering the nitrile-based monomer from an upper discharge stream from the first column; supplying a second mixed stream, in which a lower discharge stream from the first column and a base component are mixed, to a second column; and recovering the ammonia from an upper discharge stream from the second column and separating purified wastewater.

Abstract: A method of recovering a solvent including: supplying polymerization reactants including one or more monomers and a solvent to a reactor to obtain a polymer solution; supplying a stream including the polymer solution to a separator to separate an upper discharge stream including the solvent, wherein the solvent is in a gaseous phase, and a lower discharge stream including the polymer solution; heating a divergence stream including a part of the lower discharge stream from the separator by a heating device and refluxing the divergence stream to the separator; supplying a residue stream including a remainder of the lower discharge stream from the separator to a steam stripping process unit; and adjusting a vapor mass fraction of the divergence stream which is refluxed to the separator with a pressure adjustment valve after being heated by the heating device.

Abstract: A method of separating an organic solvent which may easily separate and recover an organic solvent from a mixed solution containing the organic solvent, and an organic solvent separation system capable of performing the same are disclosed herein. In some embodiments, the method includes introducing a first mixed solution into a first distillation column to recover an organic solvent and discharge a first fraction containing an unrecovered organic solvent and a high boiling point compound A to a bottom of the column, introducing a second mixed solution into a second distillation column to recover organic solvent and discharge a second fraction containing an unrecovered organic solvent and a high boiling point compound B, and introducing the first fraction and the second fraction into a third distillation column to recover an organic solvent-rich fraction and a high boiling point compound-rich fraction.

Abstract: Disclosed is a recovery method of a nitrile-based monomer including: supplying a feed stream including a nitrile-based monomer, a nitrogen compound, and water to a first distillation tower to separate the stream into a lower discharge stream and an upper discharge stream; condensing the upper discharge stream of the first distillation tower and supplying the condensed stream to a decanter to separate the stream into a water layer and an organic layer; supplying an organic layer stream discharged from the decanter to a second distillation tower to separate the stream into a lower discharge stream and an upper discharge stream; and splitting a part of the upper discharge stream from the second distillation tower and refluxing the split stream to the second distillation tower.

Abstract: A method of recovering a solvent including: supplying polymerization reactants including one or more monomers and a solvent to a reactor to obtain a polymer solution; supplying a stream including the polymer solution to a separator to separate an upper discharge stream including the solvent, wherein the solvent is in a gaseous phase, and a lower discharge stream including the polymer solution; heating a divergence stream including a part of the lower discharge stream from the separator by a heating device and refluxing the divergence stream to the separator; supplying a residue stream including a remainder of the lower discharge stream from the separator to a steam stripping process unit; and adjusting a vapor mass fraction of the divergence stream which is refluxed to the separator with a pressure adjustment valve after being heated by the heating device.

Abstract: A method of preparing a conjugated diene-based polymer is provided. The method includes: adding a conjugated diene-based monomer, a catalyst, and a solvent to parallel polymerization reactors, performing a polymerization reaction to prepare a first polymer solution including a first conjugated diene-based polymer; and adding the first polymer solution to a polymerization reactor connected in series to the parallel polymerization reactors, performing the polymerization reaction to prepare a second polymer solution including a second conjugated diene-based polymer. After the polymerization reaction in the series polymerization reactor, gas produced by polymerization heat is condensed in the series polymerization reactor and refluxed to the parallel polymerization reactors, and a reaction temperature of the series polymerization reactor is maintained to be lower than a reaction temperature of the parallel polymerization reactors by 10° C. or more.

Abstract: A continuous preparation system of a conjugated diene-based polymer having improved rolling resistance properties is provided. By utilizing the continuous preparation system, a polymerization conversion ratio at an initial stage of polymerization is easy to control, long time operation is possible and productivity is excellent.

Abstract: A method of preparing a conjugated diene-based polymer is provided including: a step of polymerizing a first conjugated diene-based monomer in solution in a first polymerization reactor to prepare a first polymer solution including a first conjugated diene-based polymer; a step of polymerizing a second conjugated diene-based monomer in solution in a second polymerization reactor to prepare a second polymer solution including a second conjugated diene-based polymer; a step of supplying a first fluid separated from the first polymer solution to a first purification unit and purifying the first fluid; and a step of supplying a second fluid separated from the second polymer solution to a second purification unit and purifying the second fluid. An apparatus for preparing a conjugated diene-based polymer is also provided.

Abstract: The present invention relates to a method for preparing a modified conjugated diene-based polymer, and more particularly, provides a method for preparing a modified conjugated diene-based polymer including a step of polymerizing a conjugated diene-based monomer in the presence of an organometal compound in a hydrocarbon solvent to prepare an active polymer which is coupled with an organometal (S1); and a step of reacting or coupling the active polymer prepared in step (S1) with a modifier (S2), wherein step (S1) is continuously performed in two or more polymerization reactors, and a polymerization conversion ratio in a first reactor among the polymerization reactors is 50% or less.

Abstract: A method of separating an organic solvent which may easily separate and recover an organic solvent from a mixed solution containing the organic solvent, and an organic solvent separation system capable of performing the same are disclosed herein. In some embodiments, the method includes introducing a first mixed solution into a first distillation column to recover an organic solvent and discharge a first fraction containing an unrecovered organic solvent and a high boiling point compound A to a bottom of the column, introducing a second mixed solution into a second distillation column to recover organic solvent and discharge a second fraction containing an unrecovered organic solvent and a high boiling point compound B, and introducing the first fraction and the second fraction into a third distillation column to recover an organic solvent-rich fraction and a high boiling point compound-rich fraction.

Abstract: The present invention relates to a method for preparing a modified conjugated diene-based polymer, and more particularly, provides a method for preparing a modified conjugated diene-based polymer including a step of polymerizing a conjugated diene-based monomer in the presence of an organometal compound in a hydrocarbon solvent to prepare an active polymer which is coupled with an organometal (S1); and a step of reacting or coupling the active polymer prepared in step (S1) with a modifier (S2), wherein step (S1) is continuously performed in two or more polymerization reactors, and a polymerization conversion ratio in a first reactor among the polymerization reactors is 50% or less.

Abstract: A method of preparing a conjugated diene-based polymer is provided. The method includes: adding a conjugated diene-based monomer, a catalyst, and a solvent to parallel polymerization reactors, performing a polymerization reaction to prepare a first polymer solution including a first conjugated diene-based polymer; and adding the first polymer solution to a polymerization reactor connected in series to the parallel polymerization reactors, performing the polymerization reaction to prepare a second polymer solution including a second conjugated diene-based polymer. After the polymerization reaction in the series polymerization reactor, gas produced by polymerization heat is condensed in the series polymerization reactor and refluxed to the parallel polymerization reactors, and a reaction temperature of the series polymerization reactor is maintained to be lower than a reaction temperature of the parallel polymerization reactors by 10° C. or more.

Abstract: A method of preparing a conjugated diene-based polymer is provided including: a step of polymerizing a first conjugated diene-based monomer in solution in a first polymerization reactor to prepare a first polymer solution including a first conjugated diene-based polymer; a step of polymerizing a second conjugated diene-based monomer in solution in a second polymerization reactor to prepare a second polymer solution including a second conjugated diene-based polymer; a step of supplying a first fluid separated from the first polymer solution to a first purification unit and purifying the first fluid; and a step of supplying a second fluid separated from the second polymer solution to a second purification unit and purifying the second fluid. An apparatus for preparing a conjugated diene-based polymer is also provided.

Abstract: The present invention relates to a method for producing unsaturated aldehydes and unsaturated carboxylic acids. According to the present invention, a method for producing unsaturated aldehydes and unsaturated carboxylic acids which can impart activity and control temperature independently in fixed catalyst layer zones in a shell-and-tube reactor, thereby exhibiting improved yield and operation stability, is provided.

Abstract: The present invention relates to a method for preparing a modified conjugated diene-based polymer, and more particularly, provides a method for preparing a modified conjugated diene-based polymer including a step of polymerizing a conjugated diene-based monomer in the presence of an organometal compound in a hydrocarbon solvent to prepare an active polymer which is coupled with an organometal (S1); and a step of reacting or coupling the active polymer prepared in step (S1) with a modifier (S2), wherein step (S1) is continuously performed in two or more polymerization reactors, and a polymerization conversion ratio in a first reactor among the polymerization reactors is 50% or less.