This is a part two of the Advance Process design project. Part one was a group project in which we carried out a feasibility study of Methanol to Olefin (MTO) plant. The plant is an extension of an existing Coal-chemical complex in China, which produces 1,000,000 tonnes of methanol from coal each year. In order to become more competitive in the market, we studied alternative routes of MTO process and designed the most efficient, least pollutant and safest plant. The aim of this individual project is to cover a detailed design of the C2 splitter distillation column which is the final step in the MTO process where ethylene and ethane are separated. As ethylene is one of the most popular petrochemical product and the demand for the product is continuously increasing each year. Therefore, to meet the customers demand the column was designed with 99.4% purity.
For the initial design calculation, the operating pressure of the column was chosen as 24bar. The diameter of the column was calculated to be around 1.66m for the stripping section, which was suitable for the sieve plate design. Using the AlChE method, the plate overall efficiency was obtained as 73%, which was in the range of the distillation column efficiencies, by using the plate efficiency the actual number of stages was obtained, 53 stages, with an overall height of the column as 35m. At 24bar the condenser duty of the column was calculated to be 2.66MW and reboiler duty 2.43MW. The design optimisation shows that as the pressure of the column increases, the capital cost of the column also increases due to the increase in a number of actual stages and the reflux ratio, mean taller and thicker column wall, will be required to meet the right specification and to handle the high pressure of the column. But, with the increasing pressure, the energy cost of the column decreases, as less energy will be required to condense the overhead vapour. The capital cost of the column outweighs the energy cost of the column. Therefore, the column total cost increases with the increase in column pressure. The optimum pressure, for the C2 splitter column, was chosen as 10bar. The reason being, low reflux ratio and less number of stages will be required, meaning the less capital cost of the column.
Inhaltsverzeichnis (Table of Contents)
- Summary.
- 1.0 Project Brief...
- 2 Project Objective.........
- 2.1 Technical Objectives:
- 2.2 Personal Objectives......
- 3 Introduction......
- 3.1 Theory.
- 3.2 Process Description............
- 4 Chemical Engineering Design.
- 4.1 Mass Balance .......
- 4.2 General Design Considerations........
- 4.3 Bubble point for the Condenser and Reboiler.
- 4.4 Minimum Number of Stages (Fenske Equation)
- 4.4:1 Minimum Reflux Ratio.
- 4.5 Gilliland Correlation .........
- 4.6 Feed-Point Location...
- 4.7 Internal Traffic…………………………….
- 4.8 Energy Balance
- 4.8:1 Condenser Duty.
- 4.8:2 Reboiler Duty....
- 4.9 Physical Properties of the Mixture..
- 4.9:1 Vapour density.
- 4.9:2 Liquid density..
- 4.10 Estimation of column diameter (Dc)...
- 4.10:1 Calculating Flooding velocity
- 4.10:2 Estimation of Downcomer area (Ad)... _
- 4.10:3 Column diameter in the Enriching section Dc:.
- 4.10:4 Column diameter in the Stripping section Dc
- 4.10:5 Summary of Calculations......
- 4.11 Provisional Plate Design
- 4.11:1 Types of tray.......
- 4.11: 2 Plate design Procedure
- 4.11: 3 Plate construction .........
- 4.12 Plate Efficiency - AIChE method....
- 4.12:1 Gas-Phase Mass Transfer Units NG
- 4.12:2 Liquid phase transfers unit NÅ..
- 4.12:3 Vapour Liquid Equilibrium diagram for HK and LK Component..
- 4.12:4 Point Efficiency can be calculated using the following equation:.
- 4.12:5 Overall Column Efficiency
- 4.12:6 Actual Number of Plates...
- 4.13 Column Height
- 4.14 Feed-Point Location
- 4.15 Design Optimisation
- 4.16 Evaluation.........
- 5.0 Mechanical Design.........
- 5.1 The Material of Construction
- 5.2 Design temperature.
- 5.3 Design Pressure........
- 5.4 Maximum Allowable Stress
- 5.5 The Welded - Joint Efficiency...
- 5.6 Corrosion Allowance..
- 5.7 Thickness of the wall under internal pressure.
- 5.8 Heads.....
- 5.8;1 Flat Head..
- 5.8;2 Hemispherical Heads.
- 5.8:3 Ellipsoidal Heads
- 5.8:4 Torispherical Heads
- 5.9 Loading analysis.....
- 5.9:1 Dead weight...........
- 5.9:2 Wind Loading....
- 5.9:3 Stresses Analysis
- 5.9:4 Check for Elastic stability or Buckling.
- 5.10 Vessel Supports.
- 5.10:1 Skirt Supports...........
- 5.10:2 Skirt support design.
- 5.11 Tensile check….............
- 5.12 Manhole size...
- 5.13 Estimation of Pipe diameter
- 5.13:1 Feed pipe diameter
- 5.13:2 Distillate Pipe Diameter
- 5.13:3 Reflux Pipe Diameter.
- 5.13:4 Bottom Pipe Diameter.
- 5.13:5 Vapour reboiler Pipe Diameter.
- 5.13:6 Enriching section Pipe Diameter.
- 5.14 Concept Drawing...
- 6.0 Data Sheet
- 7.0 Control and Instrumentation P&ID.
- 7.1 The objectives for the control system of the C04 distillation column are.
- 7.1:1 Temperature/ Composition Control for distillate and Bottom.
- 7.1:2 Pressure control for the distillation column ........
- 7.1:3 Level control in the column and reflux drum.
- 7.1:4 Liquid level in the bottom of the column.
- 7.1:5 Quality Control...........
- 7.2 Alarms, Safety Trips and Interlocks..........\n
- 7.2:1 Primary objectives
- 7.3 Instruments........
- 7.3:1 Pressure instrument
- 7.1 The objectives for the control system of the C04 distillation column are.
- 8.0 Piping & Instrument Diagram
- 8.1 Tag Sheet...
- 9.0 Economic appraisal.........
- 9.1 Capital cost....
- 9.1:1 Bridgewater Method
- 9.1:2 Zevnik and Buchanan.....
- 9.1:3 Amortisation..........\n
- 9.2 Raw materials
- 9.3 Income...
- 9.4 Operating Costs.......
- 9.4:1 Energy Costs.
- 9.4:2 Labour.
- 9.4:3 Insurance, Maintenance, Tax and Royalties
- 9.4:4 Total Fixed Capital Cost....
- 9.5 Operation at 600,000 t/y..
- 9.6 The Breakeven analysis...
- 9.8 Operation at 1000000t/y..
- 9.9 Return on Investment (ROI).
- 9.10 DCFrr.
- 9.11 Cash flow for 600,000 t/y.
- 9.12 Cash flow for 1,000,000 t/y...
- 9.13 Optimisation...
- 9.1 Capital cost....
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This project focuses on the detailed design of a C2 splitter distillation column, a crucial component of the Methanol-to-Olefin (MTO) process, with the aim of optimizing its efficiency, safety, and cost-effectiveness. The project aims to ensure the production of high-purity ethylene, a key petrochemical product in high demand.
- Chemical engineering design of a C2 splitter distillation column
- Process control and instrumentation for efficient and safe operation
- Mechanical design considerations for column construction
- Economic appraisal of the project to assess profitability
- Optimization of design parameters for cost reduction and efficiency
Zusammenfassung der Kapitel (Chapter Summaries)
- Project Brief: Provides a brief overview of the project, outlining its connection to a previous feasibility study and its focus on the design of the C2 splitter column.
- Project Objective: Defines the technical and personal objectives of the project, emphasizing the goal of producing high-purity ethylene and improving efficiency through detailed design.
- Introduction: Offers an overview of the theoretical principles behind distillation and the specific MTO process, providing context for the subsequent design steps.
- Chemical Engineering Design: Delves into the detailed design calculations, including mass balance, general design considerations, bubble point calculation, minimum number of stages determination, energy balance, physical property estimations, column diameter calculation, and plate efficiency analysis.
- Mechanical Design: Focuses on the mechanical aspects of the column's construction, including material selection, design temperature and pressure, maximum allowable stress, welded joint efficiency, corrosion allowance, thickness calculation, head types, loading analysis, vessel supports, and pipe diameter estimation.
- Control and Instrumentation: Addresses the control system for the C2 splitter column, outlining objectives, alarm systems, safety features, and instrumentation details.
- Piping & Instrument Diagram: Provides a schematic representation of the column's layout, highlighting the arrangement of pipes and instruments.
- Economic Appraisal: Evaluates the economic viability of the project, incorporating capital cost estimations, raw material costs, income projections, operating costs, and breakeven analysis.
Schlüsselwörter (Keywords)
This project focuses on key concepts such as distillation, C2 splitter column, Methanol-to-Olefin (MTO) process, ethylene production, process control, mechanical design, economic appraisal, and optimization.
- Quote paper
- Sharyar Ahmed (Author), 2016, Production of a Plant Making 600,000 t/y Methanol-to-Olefin (MTO), Munich, GRIN Verlag, https://www.hausarbeiten.de/document/903164