PLAN ESTRAT

1
SYNTHESIS OF PROPYLENE GLYCOL BY REACTIVE
DISTILLATION
S. Galán1, R. De María1 F. Domingo2 1ETSII-Unive
rsidad Politécnica de Madrid 2Repsol-YPF, ID
Downstream, Química, Energía y Gas
PROCESS SIMULATION AS A TOOL FOR THE
CONCEPTUAL DESIGN OF NEW PROCESSES
2
OUTLINE

• Propylene glycol production
• Reactive distillation
• Use of simulation through the design process
• Conceptual design
• Kinetic model development
• Pilot plant
• Results
• Steady state multiplicities
• Influence of variables

3
Reactions
4
Glycol production at Repsol-YPF

• 2 plants
• Puertollano (Spain) 20,000 t/a
• Tarragona (Spain) 50,000 t/a (_at_ 2000)
• 2/3 Tubular reactors 7 distillation columns
• Important issues
• High Water/PO ratio to maximize MPG selectivity
• Running cost related to water excess
• Changes in product demand
• Process flexibility

5
Current process
6
Reactive distillation
7
Conventional process vs. Reactive distillation
8
Simulation for Conceptual Design

• Preliminary design
• Screening of process alternatives
• Profitability analysis
• Definition of a base flowsheet

9
Simulation for Kinetic Modeling

• Experimental program
• Data regression
• Analysis of results

10
Simulation in the Pilot Plant
11
Design of the Pilot Plant
12
Temperature profiles
13
Steady State Multiplicities
14
Composition profiles
15
Reaction rate profiles
16
Feed and pressure influence
17
Pressure influence
18
Boil-up ratio influence
19
Software Tools

• ASPEN PLUS
• MATLAB for data analysis
• PITCON AUTO for detection of multiplicities by
  homotopy continuation methods
• ABACUSS for dynamic simulation

20
Conclusions

• A process for MPG by hydration of PO in a
  (reactive) distillation column is considered
  profitable.
• The interaction between reaction and separation
  introduces a more complex behaviour leading to
  new challenges in design, operation and control.
• Repsol-YPF has been applying succesfully
  simulation (Aspen Plus) as a key tool through the
  development process. At this time, in the pilot
  plant stage.

21

• Santos Galán (sgalan_at_diquima.upm.es)
• Francisco Domingo (fdomingor_at_repsol.es)
• http//www.diquima.upm.es/proyectos/glicoles/glico
  les.html