p. 1 wording basic data analysis performance flow pattern concentration temperature pressure...
TRANSCRIPT
p. 1
Wording Basic data
Analysis Performance Flow pattern
Concentration Temperature Pressure Practical reactor Diagram
Actual process Ullmann 1 Ullmann 2 Ullmann 3
Monoethanolamine
Integrated Process Design. UVa.
AIM: Develop the proposal of a block diagram and main operating conditions for a monoethanolamine plant.
Reactions:
p. 2
Wording Basic data
Analysis Performance Flow pattern
Concentration Temperature Pressure Practical reactor Diagram
Actual process Ullmann 1 Ullmann 2 Ullmann 3
Monoethanolamine
Integrated Process Design. UVa.
“The reaction of ethylene oxide with ammonia takes place slowly and is accelerated by water.”
BASIC DATA (Ullmann’s Encyclopedia of Industrial Chemistry)
“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. ”
“In all conventional processes, reaction takes place in the liquid phase, ...”
TB
(ºC)TC
(ºC)
NH3 -33 133
EO 10 196
H2O 100 374
MEA 170 405
DEA 268 463
TEA 335 499
p. 3
Wording Basic data
Analysis Performance Flow pattern
Concentration Temperature Pressure Practical reactor Diagram
Actual process Ullmann 1 Ullmann 2 Ullmann 3
Monoethanolamine
Integrated Process Design. UVa.
PERFORMANCE
Type of reaction?
Maximum selectivity
+ EO + EONH3 + EO MEA DEA TEA
Mixed reactions:NH3, MEA: Multiple in seriesEO: Multiple in parallel
Conversion target?
Multiple in series reactions: low conversion (50%?)
Performance choice?
p. 4
Wording Basic data
Analysis Performance Flow pattern
Concentration Temperature Pressure Practical reactor Diagram
Actual process Ullmann 1 Ullmann 2 Ullmann 3
Monoethanolamine
Integrated Process Design. UVa.
FLOW PATTERN
+ EO + EONH3 + EO MEA DEA TEA
CO
NC
EN
TR
AT
ION
Feed
Product
PF
CO
NC
EN
TR
AC
IÓN
Feed
Product
CSTR
NH3 PF
EO CSTR
MEA PF
NH3
EO
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.
p. 5
Wording Basic data
Analysis Performance Flow pattern
Concentration Temperature Pressure Practical reactor Diagram
Actual process Ullmann 1 Ullmann 2 Ullmann 3
Monoethanolamine
Integrated Process Design. UVa.
CONCENTRATION
+ EO + EONH3 + EO MEA DEA TEA
NH3 >> EO
Performance choice: maximum selectivity
Stoichiometric ratio?
p. 6
Wording Basic data
Analysis Performance Flow pattern
Concentration Temperature Pressure Practical reactor Diagram
Actual process Ullmann 1 Ullmann 2 Ullmann 3
Monoethanolamine
Integrated Process Design. UVa.
TEMPERATURE
+ EO + EONH3 + EO MEA DEA TEA
“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. ”
Performance choice: maximum selectivity
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.
p. 7
Wording Basic data
Analysis Performance Flow pattern
Concentration Temperature Pressure Practical reactor Diagram
Actual process Ullmann 1 Ullmann 2 Ullmann 3
Monoethanolamine
Integrated Process Design. UVa.
PRESSURE
+ EO + EONH3 + EO MEA DEA TEA
“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. ”
Objetivo: máxima selectividad
Selectivity does not depend on pressure: minimum P required to keep liquid phase (temperature depending).
“In all conventional processes, reaction takes place in the liquid phase, ...”
p. 8
Wording Basic data
Analysis Performance Flow pattern
Concentration Temperature Pressure Practical reactor Diagram
Actual process Ullmann 1 Ullmann 2 Ullmann 3
Monoethanolamine
Integrated Process Design. UVa.
PRACTICAL REACTOR
• Liquid phase reaction.
• 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.
p. 9
Wording Basic data
Analysis Performance Flow pattern
Concentration Temperature Pressure Practical reactor Diagram
Actual process Ullmann 1 Ullmann 2 Ullmann 3
Monoethanolamine
Integrated Process Design. UVa.
DIAGRAM
H2O
EO
SE
PA
RA
DO
R
EO
NH3
H2O
MEA
DEA
TEA
p. 10
Wording Basic data
Analysis Performance Flow pattern
Concentration Temperature Pressure Practical reactor Diagram
Actual process Ullmann 1 Ullmann 2 Ullmann 3
Monoethanolamine
Integrated Process Design. UVa.
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.”
p. 11
Wording Basic data
Analysis Performance Flow pattern
Concentration Temperature Pressure Practical reactor Diagram
Actual process Ullmann 1 Ullmann 2 Ullmann 3
Monoethanolamine
Integrated Process Design. UVa.
“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.”
Ullmann’s Encyclopedia of Industrial Chemistry
“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. ”
“Today, ethanolamines are produced on an industrial scale exclusively by reaction of ethylene oxide with excess ammonia, this excess being considerable in some cases ”
p. 12
Wording Basic data
Analysis Performance Flow pattern
Concentration Temperature Pressure Practical reactor Diagram
Actual process Ullmann 1 Ullmann 2 Ullmann 3
Monoethanolamine
Integrated Process Design. UVa.
Ullmann’s Encyclopedia of Industrial Chemistry