Reactive Distillation blog contains following
- History
- Principle
- Conventional Process
- MTBE Production Using Reactive Distillation
- Advantages
- Disadvantages
- Application
History
• Reactive distillation technique first applied for the recovery of ammonia in the classic solvey process during 1860s.
• Then in 1920s esterification process using homogeneous liquid phase catalyst comes into the picture.
• In 1970s, manufacturing of MTBE using hetrogeneous catalyst comes into the consideration.
Principle
• LeChatelier's law:-
For the reaction in equilibrium, if any change in any process variables like temperature, pressure or composition of reaction mass is made, reaction move in such a direction which will nullify the change.
A+B <--> C+D
Conventional Process
ɑc = 8, ɑa = 4, ɑb = 2, ɑd= 1
MTBE Production Using Reactive Distillation
(1) Water scrubber
(2) Reactor
(3) Reactive Distillation column
(4) Absorber
(5) Stripper
(1) Effect of feed:-
Increase in isobutylene percentage in feed
(a) Decrease energy cost per kg of MTBE produced
(b) Decrease in size of RD unit and associated equipments for the same production rate of MTBE
(2) Effect of excess methanol:- suppress side reaction
(3) Effect of column pressure
(4) Effect of increasing length of reaction zone
(5) Effect of separation stages
(a)reaction zone temperature reduces
(b)concentration of ether in reaction zone reduces. It reduces catalytic cracking of MTBE
(7)Effect of feed point
Various contact devices used for Reactive Distillation
• Tray column in which bed of catalyst is placed either in downcomers or above the trays.
• Packed tower using random packing elements which contain the catalyst or which may be made of the catalyst
• Packed tower using ordered packing elements which contain catalyst particles. In orderly packing element, catalyst particles are sandwiched between two supporting materials. Two types of ordered packings are used.
Advantages of Reactivate distillation
•Shifting of equilibrium
•Reduction in plant cost
• Heat integration benefits
• Avoidance of azeotropes
• Improved selectivity
Disadvantages of Reactive Distillation
• Volatility constraints
•Residence time requirements
•Operating conditions for reaction and distillation
Application of Reactive Distillation
• Manufacturing of ethylacetate from ethanol
• Manufacturing of methylacetate from methnol
• Manufacturing of butyalacetate from butanol
• Manufacturing of MTBE and ETBE
• Manufacturing of benzyl chloride from toluene
• Manufacturing of ethyl propionate from ethanol
• Manufacturing of amino resins
• Selective hydrogenation of butadine of C4 stream
• Selective hydrogenation of pentadine of C5 stream
• Selective hydrogenation of hexadine of C6 stream
• Thioetherification of mercaptens
• Alkylation of benzene to ethyl benzene
• Hydrodesulfurization of naptha