Nothing Special   »   [go: up one dir, main page]
Scribd Logo
Upload

Welcome to Scribd!

  • 61 views

    Process Department: MOHAMMAD SHUJJAT ABBAS (Trainee Engineer M&U) - Orientation Report

    Uploaded by

    Shujjat Abbas
    The document describes the process for producing polyester resin such as PET. It involves a series of esterification and polycondensation reactions between di-acid and diol components. In the first step, a paste of terephthalic acid and monoethylene glycol undergoes esterification in a reactor to form a prepolymer consisting of bis-hydroxyethyl terephthalate and short chain oligomers. This is followed by polycondensation where trans-esterification and further esterification occur through melt-phase polymerization to build molecular weight, removing condensate by-products under reduced pressure. The melt is then extruded and cut into essentially amorphous chips for further processing.

    Copyright:

    Attribution Non-Commercial (BY-NC)
    Download as PDF, TXT or read online from Scribd

    Process Department: MOHAMMAD SHUJJAT ABBAS (Trainee Engineer M&U) - Orientation Report

    Uploaded by

    Shujjat Abbas
    61 views4 pages
    The document describes the process for producing polyester resin such as PET. It involves a series of esterification and polycondensation reactions between di-acid and diol components. In the first step, a paste of terephthalic acid and monoethylene glycol undergoes esterification in a reactor to form a prepolymer consisting of bis-hydroxyethyl terephthalate and short chain oligomers. This is followed by polycondensation where trans-esterification and further esterification occur through melt-phase polymerization to build molecular weight, removing condensate by-products under reduced pressure. The melt is then extruded and cut into essentially amorphous chips for further processing.

    Original Description:

    Original Title

    Process Department

    Copyright

    © Attribution Non-Commercial (BY-NC)

    Available Formats

    PDF, TXT or read online from Scribd

    Did you find this document useful?

    Is this content inappropriate?

    The document describes the process for producing polyester resin such as PET. It involves a series of esterification and polycondensation reactions between di-acid and diol components. In the first step, a paste of terephthalic acid and monoethylene glycol undergoes esterification in a reactor to form a prepolymer consisting of bis-hydroxyethyl terephthalate and short chain oligomers. This is followed by polycondensation where trans-esterification and further esterification occur through melt-phase polymerization to build molecular weight, removing condensate by-products under reduced pressure. The melt is then extruded and cut into essentially amorphous chips for further processing.

    Copyright:

    Attribution Non-Commercial (BY-NC)
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    61 views4 pages

    Process Department: MOHAMMAD SHUJJAT ABBAS (Trainee Engineer M&U) - Orientation Report

    Uploaded by

    Shujjat Abbas
    The document describes the process for producing polyester resin such as PET. It involves a series of esterification and polycondensation reactions between di-acid and diol components. In the first step, a paste of terephthalic acid and monoethylene glycol undergoes esterification in a reactor to form a prepolymer consisting of bis-hydroxyethyl terephthalate and short chain oligomers. This is followed by polycondensation where trans-esterification and further esterification occur through melt-phase polymerization to build molecular weight, removing condensate by-products under reduced pressure. The melt is then extruded and cut into essentially amorphous chips for further processing.

    Copyright:

    Attribution Non-Commercial (BY-NC)
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 4

    MOHAMMAD SHUJJAT ABBAS (Trainee Engineer M&U) Orientation Report

    PROCESS DEPARTMENT

    Polyester resin such as PET follows a series of steps involving intermolecular reactions between bifunctional and poly-functional compounds. In the first step a paste comprising: Di-acid component, typically a solid powder Terephthalic Acid (PTA) Diol component, typically a liquid, mono ethylene glycol (MEG) The paste is charged in a first esterification stirred tank reactor maintained at around 255 to 270 degrees Celsius and pressure in the range of 0.50 to 0.95 and for a period ranging between 5.0 and 3.5 hours, resulting in an esterification process leading to the formation of a prepolymer, consisting of bis-hydroxy ethyl terephthalate [BHET] and short chain oligomers. The esterification is not complete and some acid end groups remain in the prepolymer. Water, an esterification byproduct, is removed by a column system and [EG] is recycled. The esterification steps resulting in the prepolymer is typically followed by a polycondensation step in which a trans-esterification and an esterification reaction leads to step-growth polymerization in the melt phase. These reactions are reversible and require that the condensates [EG] and water are efficiently removed from the melt, typically by using reduced pressure. Initially, when the melt viscosity remains relatively low, the condensate products can be removed easily by evaporation. However, as the viscosity increases bubble formation is hindered and diffusion of EG is required. This may be also achieved by using a disk ring reactor to reduce the diffusion path, creating a thin renewable film thereby increasing the surface area and removing the condensates. In general it is difficult to obtain PET of number average molar mass Mn greater than 20,000 g/mole [intrinsic viscosity, IV .about.0.6 dL/g] needed for making bottles . Because of reduced mass transfer rates and chemical degradation at high temperatures and long residence time. However in the disc ring reactor it is possible to reach I.V of about 0.65 without degradation, and with more antimony catalyst even higher. The melt is extruded into strands which solidify on cooling and the strands are cut into essentially amorphous chips for the post polymerization process.

    MOHAMMAD SHUJJAT ABBAS (Trainee Engineer M&U) Orientation Report

    POLYCONDENSTAION
    Paste Vessel 1414-VO1

    Esterfication I 1425 RO1

    Esterfication II 1425 RO2

    Pre Polymerization I 1435 RO1

    Pre Polymerization II 1445 RO1

    Disk Ring Reactor 1465 RO1

    Cutter

    Dryer

    MOHAMMAD SHUJJAT ABBAS (Trainee Engineer M&U) Orientation Report

    SOLID STATE POLYMERIZATION

    Surge Silo

    Pre Crystallizer

    Crystallizer I

    Crystallizer II

    Plug Flow Reactor

    Fluidized Bed Cooler

    Static Cooler

    MOHAMMAD SHUJJAT ABBAS (Trainee Engineer M&U) Orientation Report

    You might also like