A polycarbonate prepolymer, final polymerization cleaning, diphenyl carbonate and phenol recovery device

Abstract

The utility model provides a kind of polycarbonate prepolymer, final polymerization cleaning diphenyl carbonate and phenol recovery device.The utility model includes recovery pipeline system and low-pressure steam heat tracing structure;The recovery pipeline system is closed pipe, one end is fixedly connected with the prepolymers / final polymerization process cleaning material discharge of polycarbonate production line, another end is detachably connected with the import of diphenyl carbonate and phenol recovery closed storage tank;The recovery pipeline system sequentially includes DN80 pipe section, DN80 / DN25 concentric reducing joint, DN25 pipe section along material conveying direction, and each pipe section and reducing joint are fixed by welding;The low-pressure steam heat tracing structure is wrapped in the outside of recovery pipeline system, for maintaining the material in pipe is liquid state.The utility model uses closed recovery pipeline system, there is no material spilling phenomenon, and the recovery rate of diphenyl carbonate and phenol is high, and a large amount of material waste can be reduced annually.

Description

Technical Field

[0001] This utility model relates to the field of auxiliary equipment and process technology for polycarbonate (PC) production, and in particular to a device for prepolymerizing and finalizing polycarbonate, cleaning diphenyl carbonate, and recovering phenol. Background Technology

[0002] Polycarbonate is a high-performance engineering plastic widely used in electronics, automotive, and construction. When producing polycarbonate using the melt transesterification process, after the prepolymerization and final polymerization steps, the equipment needs to be cleaned. This cleaning process generates a liquid mixture containing diphenyl carbonate and phenol. Current technology lacks a dedicated closed-loop pipeline system for recovering this mixture. The cleaned diphenyl carbonate and phenol mixture is directly discharged into a recovery tank through a simple outlet. Because the material is liquid and highly fluid, and there is no dedicated connection between the outlet and the tank, spillage is highly likely. This discharge method has the following drawbacks: First, the spilled diphenyl carbonate and phenol cannot be recovered, leading to reduced raw material utilization and increased production costs. Second, diphenyl carbonate and phenol are corrosive and toxic, and spillage can easily come into contact with the skin and respiratory tract of operators, causing safety accidents. Third, the spilled material can contaminate the production site, seep into the soil, or flow into the wastewater system, failing to meet environmental emission requirements. Utility Model Content

[0003] To address the aforementioned technical problems, a device for prepolymerizing and finalizing polycarbonate, cleaning diphenyl carbonate, and recovering phenol is provided. The technical means employed in this invention are as follows: A polycarbonate prepolymerization and final polymerization cleaning device for diphenyl carbonate and phenol recovery includes a recovery pipeline system and a low-pressure steam tracing structure. The recovery pipeline system is a closed pipeline, with one end fixedly connected to the discharge port of the prepolymerization / final polymerization cleaning process of the polycarbonate production line, and the other end detachably connected to the inlet of a closed storage tank for diphenyl carbonate and phenol recovery. The recovery pipeline system consists of a DN80 pipe section, a DN80 / DN25 concentric reducer, and a DN25 pipe section sequentially along the material conveying direction, with each pipe section and reducer fixed by welding. The low-pressure steam tracing structure is wrapped around the outside of the recovery pipeline system to maintain the material inside the pipeline in a liquid state.

[0004] Furthermore, the other end of the recovery pipeline system is connected to the inlet of the closed storage tank for the recovery of diphenyl carbonate and phenol via a flange with specifications of PN1.0MPa and DN25.

[0005] Furthermore, the low-pressure steam heat tracing structure includes a heat tracing pipe and an insulation layer. The heat tracing pipe is spirally wound around the outer wall of the recovery pipe, and the insulation layer is wrapped around the outside of the heat tracing pipe.

[0006] Furthermore, the length of the DN80 pipe section is 1.5-3m, the length of the DN25 pipe section is 0.5-1m, and the length of the concentric reducer is 100-150mm.

[0007] This utility model has the following advantages: 1. This utility model adopts a closed-loop recycling pipeline system, which eliminates material spillage and achieves high recovery rates of diphenyl carbonate and phenol, thereby reducing a significant amount of material waste annually.

[0008] 2. The entire recycling process of this utility model is sealed, and operators do not need to directly contact the materials, completely eliminating the risk of personal injury caused by the corrosiveness and toxicity of diphenyl carbonate and phenol. No safety accidents have occurred since its operation.

[0009] 3. The low-pressure steam heating structure of this utility model avoids material solidification and blockage of the pipeline, and the pipeline specifications are compatible with the prepolymerization / final polymerization process cleaning material discharge port of the existing polycarbonate production line. It is connected to the sealed storage tank for diphenyl carbonate and phenol recovery, without the need for major modifications to the existing equipment, and is easy to install. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a system diagram of the present utility model. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0013] like Figure 1As shown in the figure, this utility model discloses a polycarbonate prepolymerization and final polymerization cleaning device for diphenyl carbonate and phenol recovery, including a recovery pipeline system and a low-pressure steam heating structure. The recovery pipeline system is a closed pipeline, one end of which is fixedly connected to the cleaning material discharge port of the prepolymerization / final polymerization process of the polycarbonate production line, and the other end is detachably connected to the inlet (N14) of the closed storage tank for diphenyl carbonate and phenol recovery (V-6510 in the figure). The polycarbonate production line (formerly PC unit) is a complete production line equipment for producing polycarbonate (including processes such as 119P and 119E shown in the figure), including core processes such as prepolymerization, final polymerization, and cleaning, and is the source of the mixed cleaning liquid of diphenyl carbonate and phenol. The cleaning material outlet valves of the prepolymerization process 2 and the final polymerization process on the polycarbonate production line correspond to three different cleaning stations (SD-41 / 42 / 43-01 in the figure), which are the discharge ports of the mixed liquid of diphenyl carbonate and phenol, and are the starting point of the recovery process. In the diagram, the closed storage tank for diphenyl carbonate and phenol recovery (formerly the V-6510 storage tank) is a closed container specifically for storing recovered materials. It is used to collect the recovered diphenyl carbonate and phenol mixture and is the end point of the recovery process. The recovered materials can then be reused in production.

[0014] The recycling pipeline system consists of a DN80 pipe section, a DN80 / DN25 concentric reducer, and a DN25 pipe section, arranged sequentially along the material conveying direction. Each pipe section and reducer is fixed by welding. The low-pressure steam heating structure is wrapped around the outside of the recycling pipeline system to maintain the material inside the pipeline in a liquid state.

[0015] Furthermore, the other end of the recovery pipeline system is connected to the inlet of the closed storage tank for the recovery of diphenyl carbonate and phenol via a flange with specifications of PN1.0MPa and DN25.

[0016] Furthermore, the low-pressure steam heat tracing structure includes a heat tracing pipe and an insulation layer. The heat tracing pipe is spirally wound around the outer wall of the recovery pipe, and the insulation layer is wrapped around the outside of the heat tracing pipe.

[0017] Furthermore, the length of the DN80 pipe section is 1.5-3m, the length of the DN25 pipe section is 0.5-1m, and the length of the concentric reducer is 100-150mm.

[0018] In actual use, a pneumatic test is conducted on the pipeline before recycling to ensure its airtightness; then low-pressure steam is introduced to preheat the pipeline, and the next step is carried out after the temperature stabilizes. Slowly open the valves of the prepolymer / final polymerization process cleaning material discharge ports (outlet valves of the 3 cleaning stations), adjust the opening to control the material conveying flow rate, and the mixed material enters along the DN80 pipe section. After being depressurized and stabilized by the concentric reducer, it is smoothly conveyed to the diphenyl carbonate and phenol recovery sealed storage tank through the DN25 pipe section. Throughout the conveying process, low-pressure steam is continuously introduced into the heat tracing pipe to reduce heat loss through the insulation layer and maintain a stable temperature inside the pipeline. The material enters the sealed storage tank through the N14 port of the diphenyl carbonate and phenol recovery tank for sealed storage, and can be recycled and reused later.

[0019] This invention, through the combined design of a dedicated closed-loop recovery pipeline system and a low-pressure steam heating structure, completely solves the problems of material waste, personnel injury, and environmental pollution during the prepolymerization and final polymerization cleaning process of polycarbonate, and has significant economic, safety, and environmental benefits. It has a simple structure, is easy to install and maintain, and can be widely used in enterprises that produce polycarbonate using the melt transesterification method, and has good promotional value.

[0020] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A device for cleaning diphenyl carbonate and recovering phenol from polycarbonate prepolymerization and final polymerization, characterized in that, The system includes a recovery pipeline system and a low-pressure steam tracing structure. The recovery pipeline system is a closed pipeline, with one end fixedly connected to the discharge port of the prepolymer / final polymerization process cleaning material of the polycarbonate production line, and the other end detachably connected to the inlet of the closed storage tank for diphenyl carbonate and phenol recovery. The recovery pipeline system consists of a DN80 pipe section, a DN80 / DN25 concentric reducer, and a DN25 pipe section, arranged sequentially along the material conveying direction. Each pipe section and reducer is fixed by welding. The low-pressure steam tracing structure is wrapped around the outside of the recovery pipeline system to maintain the material inside the pipeline in a liquid state.

2. The polycarbonate prepolymerization, final polymerization cleaning diphenyl carbonate and phenol recovery device according to claim 1, characterized in that, The other end of the recovery pipeline system is connected to the inlet of the closed storage tank for the recovery of diphenyl carbonate and phenol via a flange with specifications of PN1.0MPa and DN25.

3. The polycarbonate prepolymerization, final polymerization cleaning diphenyl carbonate and phenol recovery device according to claim 1, characterized in that, The low-pressure steam heat tracing structure includes a heat tracing pipe and an insulation layer. The heat tracing pipe is spirally wound around the outer wall of the recovery pipe, and the insulation layer is wrapped around the outside of the heat tracing pipe.

4. The polycarbonate prepolymerization, final polymerization cleaning diphenyl carbonate and phenol recovery device according to claim 1, characterized in that, The length of the DN80 pipe section is 1.5-3m, the length of the DN25 pipe section is 0.5-1m, and the length of the concentric reducer is 100-150mm.

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