1. Methane to Aromatics
Aric Von Buettner

2. Background Current glut (valley) in natural gas prices
High BTX product demand
North America currently imports benzene to meet demand
This enables a sizable opportunity for processes that convert natural gas to benzene that has no sign of becoming smaller

3. Process Overview and Issues
Use natural gas as the feedstock to produce 728 million lb/yr of mixed benzene and toluene
Molybdenum catalyst facilitates reaction
Can become deactivated due to coking
Various byproducts as result of reaction
Hydrogen and Naphthalene

4. Process Flow Diagram Recycle Section Separation Section
Reactor Section

5. Catalyst Research Each group member found catalyst
I presented my research on Mo/ZSM-5
After discussion, chose Mo/H-MFI instead

6. Constraints Constraint Type of constraint Constraint met (Y/N)
How? (Design value)
Air Pollution
Environmental Y
Apply for permit
Energy Consumption (depletion of natural resource NG)
Brief analysis of NG market
Cost of chemicals
Economic
Economic sensitivities
Feedstock limited by amount that is produced
Product/Feedstock
Comparing our use to total production
Unit Op Material Compatibility with chemicals
Safety
Use stainless steel for unit ops

7. Design Layout and Optimization
Used Visio to create initial process flow diagram
Later helped rest of group in making initial Aspen model, converging it
Optimization of distillation tower

8. Unit Operations Sizing and Pricing
Hydrogen membrane
Allowable hydrogen flow rate
Membrane cost $/ft^2
Change in pressure
Hydrogen purity

9. Products: Benzene and Toluene
Economic analysis
Chemical costing
Products: Benzene and Toluene
Naphthalene
Purge fuel use

10. Alternative catalysts
Design Alternatives
Mo/ZSM-5
Mo/MCM-22
Alternative catalysts
5% of stream coming out of hydrogen membrane
Purge
Burn entire vent stream
Vent
Mo/H-MFI-B catalyst
1% purge stream
Separate aromatics from vent stream
Base case

11. Safety and Risk Management
Heat Exchangers
Reactor
Distillation tower
Safety issues
Large Temperature deviations from norm
Risks Management: Adjusting cold or hot stream flow
Temperature and Pressure deviations
HTFA
Risk Management: Use stainless steel, lower/raise heating/cooling and feed streams,
Leaks
Obstruction of feed stream
Risk Management: Install level alarm and feed flow-rate meter

12. HAZOP Analysis Table
Helpful tool in analyzing the risks with each unit op, along with how to make them safer
Example:
Unit Op
Guideword
Deviation
Causes
Consequences
Action required
Distillation tower
Utility failure
Failure
Power to reboiler stopped
Insufficient reheating resulting in impure bottoms product
Install temp. sensor

13. Broader Impacts / Contemporary Issues
Job Creation from methane development
CO2 emissions contributing to global greenhouse effect
Texas state incentives for chemical plants

14. Questions?