Transcript Monoethanolamine production - IQ

Monoethanolamine
Wording
Basic data
Analysis
Performance
Flow pattern
Concentration
Temperature
Pressure
Practical reactor
Diagram
AIM: Develop the proposal of a block diagram and main operating
conditions for a monoethanolamine plant.
Reactions:
Actual process
Ullmann 1
Ullmann 2
Ullmann 3
Integrated Process Design. UVa.
p. 1
Monoethanolamine
BASIC DATA
Wording
Basic data
Analysis
Performance
Flow pattern
Concentration
Temperature
Pressure
Practical reactor
Diagram
Actual process
Ullmann 1
Ullmann 2
Ullmann 3
(Ullmann’s Encyclopedia of Industrial Chemistry)
“In all conventional processes, reaction takes place in the liquid phase, ...”
“The reaction of ethylene oxide with ammonia takes place slowly and is
accelerated by water.”
“The reaction is highly exothermic; the enthalpy of reaction is about
125 kJ per mole of ethylene oxide. ”
“All the reaction steps have about the same activation energy and show a
roughly quadratic dependence of the reaction rate on the water content of
the ammonia – water mixture used. ”
Integrated Process Design. UVa.
TB
(ºC)
TC
(ºC)
NH3
-33
133
EO
10
196
H2O
100
374
MEA
170
405
DEA
268
463
TEA
335
499
p. 2
Monoethanolamine
Wording
Basic data
Analysis
Performance
Flow pattern
Concentration
Temperature
Pressure
Practical reactor
Diagram
Actual process
Ullmann 1
Ullmann 2
Ullmann 3
PERFORMANCE
NH3 + EO 

+ EO
MEA 
+ EO
DEA 
TEA
Type of reaction?
Mixed reactions:
NH3, MEA: Multiple in series
EO: Multiple in parallel
Performance choice?
Maximum selectivity
Conversion target?
Multiple in series reactions: low conversion (50%?)
Integrated Process Design. UVa.
p. 3
Monoethanolamine
FLOW PATTERN
+ EO
NH3 + EO 

Analysis
Performance
Flow pattern
Concentration
Temperature
Pressure
Practical reactor
Diagram
MEA 
CONCENTRATION
PF
Actual process
Ullmann 1
Ullmann 2
Ullmann 3
Product
Feed

NH3 

PF
EO 

CSTR
MEA 

PF
Integrated Process Design. UVa.
+ EO
DEA 
TEA
CSTR
CONCENTRACIÓN
Wording
Basic data
For safety reasons, ethylene oxide must be metered into the
ammonia stream ; in the reverse procedure, ammonia or
amines may cause ethylene oxide to undergo an explosive
polymerization reaction.
Product
Feed

NH3
EO
p. 4
Monoethanolamine
Wording
Basic data
CONCENTRATION
NH3 + EO 

Analysis
Performance
Flow pattern
Concentration
Temperature
Pressure
Practical reactor
Diagram
+ EO
MEA 
+ EO
DEA 
TEA
Performance choice: maximum selectivity
Stoichiometric ratio?
NH3 >> EO
Actual process
Ullmann 1
Ullmann 2
Ullmann 3
Integrated Process Design. UVa.
p. 5
Monoethanolamine
Wording
Basic data
TEMPERATURE
NH3 + EO 

Analysis
Performance
Flow pattern
Concentration
Temperature
Pressure
Practical reactor
Diagram
Actual process
Ullmann 1
Ullmann 2
Ullmann 3
+ EO
MEA 
+ EO
DEA 
TEA
Performance choice: maximum selectivity
“All the reaction steps have about the same activation energy and show
a roughly quadratic dependence of the reaction rate on the water
content of the ammonia – water mixture used. ”
Selectivity does not depend on temperature: maximum T (reduces
reactor volume).
“The reaction is highly exothermic ; the enthalpy of reaction is about 125
kJ per mole of ethylene oxide. ”
Intensive cooling required.
Integrated Process Design. UVa.
p. 6
Monoethanolamine
Wording
Basic data
PRESSURE
NH3 + EO 

Analysis
Performance
Flow pattern
Concentration
Temperature
Pressure
Practical reactor
Diagram
Actual process
Ullmann 1
Ullmann 2
Ullmann 3
+ EO
MEA 
+ EO
DEA 
TEA
Objetivo: máxima selectividad
“All the reaction steps have about the same activation energy and show
a roughly quadratic dependence of the reaction rate on the water
content of the ammonia – water mixture used. ”
“In all conventional processes, reaction takes place in the liquid phase, ...”
Selectivity does not depend on pressure: minimum P required to
keep liquid phase (temperature depending).
Integrated Process Design. UVa.
p. 7
Monoethanolamine
Wording
Basic data
PRACTICAL REACTOR
• Liquid phase reaction.
Analysis
Performance
Flow pattern
Concentration
Temperature
Pressure
Practical reactor
Diagram
Actual process
Ullmann 1
Ullmann 2
Ullmann 3
• Homogeneous catalytic.
• Flow pattern: PF (NH3 and MEA) and CSTR (EO).
• Highly exothermic: cooling required
• High pressure.
“The reaction of ethylene oxide with ammonia takes place slowly and is
accelerated by water.”
• High residence time.
Multi-tubular cooled reactor, with multiple intermediate EO feed
points.
Integrated Process Design. UVa.
p. 8
Monoethanolamine
Wording
Basic data
DIAGRAM
EO
Analysis
Performance
Flow pattern
Concentration
Temperature
Pressure
Practical reactor
Diagram
H2O
SEPARADOR
Actual process
Ullmann 1
Ullmann 2
Ullmann 3
NH3
H2O
MEA
DEA
TEA
EO
Integrated Process Design. UVa.
p. 9
Monoethanolamine
Wording
Basic data
Analysis
Performance
Flow pattern
Concentration
Temperature
Pressure
Practical reactor
Diagram
Ullmann’s Encyclopedia of Industrial Chemistry
“All the reaction steps have about the same activation energy and show a
roughly quadratic dependence of the reaction rate on the water content of
the ammonia – water mixture used. Therefore, product composition
depends solely on the molar excess of ammonia and not on water
content, reaction temperature, or pressure. The product distribution as a
function of the molar ratio of the reactants is shown in Figure.”
Actual process
Ullmann 1
Ullmann 2
Ullmann 3
Integrated Process Design. UVa.
p. 10
Monoethanolamine
Wording
Basic data
Analysis
Performance
Flow pattern
Concentration
Temperature
Pressure
Practical reactor
Diagram
Actual process
Ullmann 1
Ullmann 2
Ullmann 3
Ullmann’s Encyclopedia of Industrial Chemistry
“Today, ethanolamines are produced on an industrial scale exclusively
by reaction of ethylene oxide with excess ammonia, this excess being
considerable in some cases ”
“In all conventional processes, reaction takes place in the liquid phase,
and the reactor pressure must be sufficiently large to prevent
vaporization of ammonia at the reaction temperature.”
“In current procedures, ammonia concentrations in water between 50
and 100 % , pressures up to 16 MPa (160 bar), reaction temperatures
up to 150 °C, and an excess up to 40 mol of ammonia per mole of
ethylene oxide are used. ”
Integrated Process Design. UVa.
p. 11
Monoethanolamine
Wording
Basic data
Ullmann’s Encyclopedia of Industrial Chemistry
Analysis
Performance
Flow pattern
Concentration
Temperature
Pressure
Practical reactor
Diagram
Actual process
Ullmann 1
Ullmann 2
Ullmann 3
Integrated Process Design. UVa.
p. 12