In an embodiment, a method of manufacture of a melt polycarbonate comprises melt polymerizing a bisphenol and diphenyl carbonate to form phenol and the melt polycarbonate in a polymerization unit; removing an overhead stream comprising the phenol in a gas phase from the polymerization unit; combining the overhead stream with a gas stream comprising a solvent in a gas phase to form a combined gas stream; wherein the combined gas stream has a freezing point at less than 3 mbar absolute that is less than the triple point of phenol; and condensing the combined gas stream in a condenser to form a condensed stream comprising the phenol and the solvent in a liquid phase.

In an embodiment, a method of manufacture of a melt polycarbonate comprises melt polymerizing a bisphenol and diphenyl carbonate to form phenol and the melt polycarbonate in a polymerization unit; removing an overhead stream comprising the phenol in a gas phase from the polymerization unit; combining the overhead stream with a gas stream comprising a solvent in a gas phase to form a combined gas stream; wherein the combined gas stream has a freezing point at less than 3 mbar absolute that is less than the triple point of phenol; and condensing the combined gas stream in a condenser to form a condensed stream comprising the phenol and the solvent in a liquid phase.

A method of decomposing a phenol by-product produced in a phenol preparation process, in which acetophenone separated from a distillation column is mixed with tar separated and collected in a decomposition reactor, thereby significantly decreasing viscosity of tar. The decomposition method according to the present invention allows tar to have sufficient viscosity for flowability even at room temperature, whereby transfer and storage of tar may be more smoothly done without using any heating device for transfer of tar.

A method of decomposing a phenol by-product produced in a phenol preparation process, in which acetophenone separated from a distillation column is mixed with tar separated and collected in a decomposition reactor, thereby significantly decreasing viscosity of tar. The decomposition method according to the present invention allows tar to have sufficient viscosity for flowability even at room temperature, whereby transfer and storage of tar may be more smoothly done without using any heating device for transfer of tar.

The present disclosure provides a method for decomposing a phenolic by-product, the method including: a step S10 of injecting and mixing a bisphenol A by-product produced in a bisphenol A production process, a mixed by-product stream of phenol by-products produced in a phenol production process, a decomposition apparatus side discharge stream, and a process water stream in a mixing apparatus; a step S20 of injecting a mixing apparatus discharge stream discharged from the mixing apparatus into a phase separation apparatus and phase-separating the mixing apparatus discharge stream into an oil-phase stream and a liquid-phase stream; a step S30 of feeding the oil-phase stream, which is phase-separated in the step S20 and discharged from the phase separation apparatus, to a decomposition apparatus to decompose the oil-phase stream; and a step S40 of circulating the decomposition apparatus side discharge stream obtained by the decomposition in the step S30 to the mixing apparatus in the step S10.

The present disclosure provides a method for decomposing a phenolic by-product, the method including: a step S10 of injecting and mixing a bisphenol A by-product produced in a bisphenol A production process, a mixed by-product stream of phenol by-products produced in a phenol production process, a decomposition apparatus side discharge stream, and a process water stream in a mixing apparatus; a step S20 of injecting a mixing apparatus discharge stream discharged from the mixing apparatus into a phase separation apparatus and phase-separating the mixing apparatus discharge stream into an oil-phase stream and a liquid-phase stream; a step S30 of feeding the oil-phase stream, which is phase-separated in the step S20 and discharged from the phase separation apparatus, to a decomposition apparatus to decompose the oil-phase stream; and a step S40 of circulating the decomposition apparatus side discharge stream obtained by the decomposition in the step S30 to the mixing apparatus in the step S10.

The present invention relates to the fractionation technology that is used to create purified phenol and acetone products. More specifically, the present invention relates to a fractionation technology that is used to create crude acetone and crude phenol streams using a dividing wall column intended to remove cumene, alpha-methyl styrene and water from the product side of the wall.

Provided is a method of decomposing phenolic by-products, and more particularly, a method of decomposing phenolic by-products including: supplying a phenolic by-product stream to a decomposition device to perform thermal decomposition; separating an upper discharge stream including effective components and a lower discharge stream including materials having a high boiling point in the decomposition device; supplying the lower discharge stream from the decomposition device, a side discharge stream from the decomposition device, and a process water stream to a mixing device and mixing these streams; and supplying a discharge stream from the mixing device to a layer separation device to separate the discharge stream from the mixing device into an oil phase and an aqueous phase.

Provided is a method of decomposing phenolic by-products, and more particularly, a method of decomposing phenolic by-products including: supplying a phenolic by-product stream to a decomposition device to perform thermal decomposition; separating an upper discharge stream including effective components and a lower discharge stream including materials having a high boiling point in the decomposition device; supplying the lower discharge stream from the decomposition device, a side discharge stream from the decomposition device, and a process water stream to a mixing device and mixing these streams; and supplying a discharge stream from the mixing device to a layer separation device to separate the discharge stream from the mixing device into an oil phase and an aqueous phase.

Provided is a method of decomposing phenolic by-products, and more particularly, a method of decomposing phenolic by-products including: supplying a phenolic by-product stream to a decomposition device to perform thermal decomposition; separating an upper discharge stream including effective components and a lower discharge stream including materials having a high boiling point in the decomposition device; supplying the lower discharge stream from the decomposition device, a side discharge stream from the decomposition device, and a process water stream to a mixing device and mixing these streams; and supplying a discharge stream from the mixing device to a layer separation device to separate the discharge stream from the mixing device into an oil phase and an aqueous phase.