Polyethylene Terephthalate

Molecular Structure

Molecular Details

Molecular Formula	(C₁₀H₈O₄)ₙ
Molecular Weight	Variable (polymer)
State	Solid at standard conditions

Olefinverbund Integration

Chemistry & Engineering

Reaction Equation	Esterification + Polycondensation
Thermodynamics	Equilibrium usually driven by vacuum (removal of EG/Water)
Catalyst System	Antimony or Titanium compounds
Reactor Class	Melt reactor followed by Solid State Polymerization (SSP)
Process Considerations	SSP increases Intrinsic Viscosity (IV) for bottle strength.

Extraterrestrial Production Pattern

1. Esterification: PTA + EG → bis(hydroxyethyl) terephthalate
2. Polycondensation at 280-300°C under vacuum
3. Sb or Ti catalyst for condensation
4. Solid-state polymerization for high IV grades

Applications

• Beverage bottles
• Polyester textile fibers
• Food packaging films
• Engineering plastics

Reaction Diagram

Overall Reaction: PTA + MEG -> PET + H2O

Unit Operations

Process steps following chemical engineering unit operation principles:

Step	Operation	Description
1	PTA/MEG Slurry	Prepare slurry of PTA in excess MEG
2	Esterification	Form BHET at 250-280°C
3	Polycondensation	Remove MEG under vacuum at 270-290°C
4	Chipping	Strand extrude and cut to chips
5	SSP	Solid-state polymerize for bottle grade
6	Crystallization	Crystallize amorphous chips

S88 Batch Control Model

This module follows the ISA-88 (S88) batch control standard. Below is a simplified BatchML schema for educational purposes:

<?xml version="1.0" encoding="UTF-8"?>
<!-- ISA-88 Batch Control Model for Polyethylene Terephthalate -->
<!-- Educational schema - simplified for demonstration -->
<BatchML xmlns="http://www.wbf.org/xml/B2MML-V0600">
  
  <ProcessCell ID="PET_PLANT_CELL">
    <Description>Process cell for Polyethylene Terephthalate production</Description>
    
    <Unit ID="PET_PLANT">
      <Description>Main synthesis unit</Description>
      
      <!-- Equipment Modules -->
      <EquipmentModule ID="SLURRY_TANK">
        <Description>Slurry Tank</Description>
      </EquipmentModule>
      <EquipmentModule ID="ESTERIFIER">
        <Description>Esterifier</Description>
      </EquipmentModule>
      <EquipmentModule ID="FINISHER">
        <Description>Finisher</Description>
      </EquipmentModule>
      <EquipmentModule ID="CHIPPER">
        <Description>Chipper</Description>
      </EquipmentModule>
      <EquipmentModule ID="SSP_REACTOR">
        <Description>Ssp Reactor</Description>
      </EquipmentModule>
      <EquipmentModule ID="CRYSTALLIZER">
        <Description>Crystallizer</Description>
      </EquipmentModule>
    </Unit>
  </ProcessCell>
  
  <MasterRecipe ID="PET_PLANT_RECIPE">
    <Description>Master recipe for Polyethylene Terephthalate</Description>
    <ProductID>POLYETHYLENE_TEREPHTHALATE</ProductID>
    
    <UnitProcedure ID="PET_PLANT_UP">
      <Description>Unit procedure for synthesis</Description>
      
      <Operation ID="OP_01">
        <Description>Operation 1</Description>
        <Phase ID="SLURRY">
          <Description>Slurry phase</Description>
          <PhaseLogic>
            <Step ID="STEP_1"><Action>Initialize</Action></Step>
            <Step ID="STEP_2"><Action>Execute</Action></Step>
            <Step ID="STEP_3"><Action>Complete</Action></Step>
          </PhaseLogic>
        </Phase>
      </Operation>
      
      <Operation ID="OP_02">
        <Description>Operation 2</Description>
        <Phase ID="ESTERIFY">
          <Description>Esterify phase</Description>
          <PhaseLogic>
            <Step ID="STEP_1"><Action>Initialize</Action></Step>
            <Step ID="STEP_2"><Action>Execute</Action></Step>
            <Step ID="STEP_3"><Action>Complete</Action></Step>
          </PhaseLogic>
        </Phase>
      </Operation>
      
      <Operation ID="OP_03">
        <Description>Operation 3</Description>
        <Phase ID="POLYCONDENSE">
          <Description>Polycondense phase</Description>
          <PhaseLogic>
            <Step ID="STEP_1"><Action>Initialize</Action></Step>
            <Step ID="STEP_2"><Action>Execute</Action></Step>
            <Step ID="STEP_3"><Action>Complete</Action></Step>
          </PhaseLogic>
        </Phase>
      </Operation>
      
      <Operation ID="OP_04">
        <Description>Operation 4</Description>
        <Phase ID="CHIP">
          <Description>Chip phase</Description>
          <PhaseLogic>
            <Step ID="STEP_1"><Action>Initialize</Action></Step>
            <Step ID="STEP_2"><Action>Execute</Action></Step>
            <Step ID="STEP_3"><Action>Complete</Action></Step>
          </PhaseLogic>
        </Phase>
      </Operation>
      
      <Operation ID="OP_05">
        <Description>Operation 5</Description>
        <Phase ID="SSP">
          <Description>Ssp phase</Description>
          <PhaseLogic>
            <Step ID="STEP_1"><Action>Initialize</Action></Step>
            <Step ID="STEP_2"><Action>Execute</Action></Step>
            <Step ID="STEP_3"><Action>Complete</Action></Step>
          </PhaseLogic>
        </Phase>
      </Operation>
      
      <Operation ID="OP_06">
        <Description>Operation 6</Description>
        <Phase ID="CRYSTALLIZE">
          <Description>Crystallize phase</Description>
          <PhaseLogic>
            <Step ID="STEP_1"><Action>Initialize</Action></Step>
            <Step ID="STEP_2"><Action>Execute</Action></Step>
            <Step ID="STEP_3"><Action>Complete</Action></Step>
          </PhaseLogic>
        </Phase>
      </Operation>
    </UnitProcedure>
  </MasterRecipe>
  
</BatchML>

**Key S88 Concepts:**
- **Process Cell**: The physical grouping containing all equipment for this process
- **Unit**: The major equipment that performs the synthesis
- **Equipment Modules**: Individual pieces of equipment (reactors, columns, etc.)
- **Unit Procedure**: The sequence of operations to produce the product
- **Phases**: The lowest level of procedural control (e.g., REACT, SEPARATE, PURIFY)

Key S88 Concepts:
• Process Cell: Physical grouping containing all equipment
• Unit: Major equipment performing synthesis
• Equipment Modules: Individual pieces (reactors, columns, etc.)
• Phases: Lowest level of procedural control (REACT, SEPARATE, etc.)

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This Synthesis Module is part of the 100chemicals Olefinverbund — an integrated chemical production network designed for extraterrestrial civilization on Moon and Mars.