Hydrodealkylation of Toluene Plant Simulation and Economic Feasibility Study

Project Overview

This project involves the conceptual design and economic feasibility analysis of a Hydrodealkylation (HDA) plant for toluene. The main objectives are to simulate the HDA process using MATLAB and Aspen HYSYS and to assess the economic viability of the plant over an operating year.

Key Reactions

• Primary Reaction:

  • Toluene (C7H8) reacts with hydrogen (H2) to produce benzene (C6H6) and methane (CH4).
  • Reaction: C7H8 + H2 → C6H6 + CH4

• Secondary (Undesired) Reaction:

  • Benzene (C6H6) reacts to form biphenyl (C12H10) and hydrogen (H2).
  • Reaction: 2C6H6 → C12H10 + H2

Project Structure

1. Introduction: Overview of the hydrodealkylation of toluene and its industrial significance.
2. Process Scheme: Detailed process diagrams, including Block Flow Diagram (BFD) and Process Flow Diagram (PFD).
3. Material Balance and Degree of Freedom (DOF) Analysis: Comprehensive material balance calculations for various process components.
4. Reactor Design: Design considerations and governing equations for the reactor.
5. Economic Potential Analysis:
   • EP1: Reactor Selection
   • EP2: Optimization of Hydrogen Vent Stream
   • EP3: Cost Analysis of Reactor and Compression
   • EP4: Design and Cost Analysis of the Separation Train

Simulation Tools

• MATLAB: Used for reactor design and simulation.
• Aspen HYSYS: Used for process simulation and optimization.

Economic Feasibility

The economic assessment is performed through a hierarchical approach with five levels of economic potential evaluation. The study focuses on the first four levels, excluding the Heat Exchange Network:

1. Batch Operation vs. Continuous Operation
2. Input-Output Structure of Flowsheet
3. Recycle Structure of the Flowsheet
4. General Structure of the Separation System

Conclusions

• The optimal temperature for the process is determined to be 600°C.
• Further detailed evaluations are recommended using additional data and techniques for more accurate economic potential calculations.

Authors

• MohammadSina GhanbariPakdehi
• Matteo Robbiano

Acknowledgments

• Instructors: Prof. Davide Manca, Ing. Andrea Isella
• Institution: School of Industrial and Information Engineering, Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Master of Science in Chemical Engineering, Process Systems Engineering A.