falling film sulphonation

BY

ANAY NILESH KACHARIA&

GURUPRASAD VENKATAKRISHNA RAO

CONTINOUS SULPHONATION

PLANT

IMP NOTE

• IN SULPHONATION SO3 REACTS WITH ORGANIC MOLECULE TO PRODUCE SULPHUR AND CARBON BOND.

• SULFATION ON OTHER HAND IS FORMATION OF SULPHUR-OXYGEN-CARBON BOND.

SULPHONATION

• SO3 is an aggressive electrophilic reagent that rapidly reacts with any organic compound containing an electron donor group.

• Sulfonation is a difficult reaction to perform on an industrial scale because the reaction is rapid and highly exothermic, releasing approximately 380 kJ/kg SO3 (800 BTUs per pound of SO3) reacted.

SULPHONATION

• Most organic compounds form a black char on contact with pure SO3 due to the rapid reaction and heat evolution.

• Additionally, as shown in Figure, the reactants increase in viscosity between 15 and 300 times as they are converted from the organic feedstock to the sulfonic acid.

SULPHONATION THIS LARGE INCREASE IN VISCOSITY MAKES HEAT REMOVAL DIFFICULT. THE HIGH VISCOSITY OF THE FORMED PRODUCTS REDUCES THE HEAT TRANSFER COEFFICIENT FROM THE REACTION MASS.

EFFECTIVE COOLING OF THE REACTION MASS IS ESSENTIAL BECAUSE HIGH TEMPERATURES PROMOTE SIDE REACTIONS THAT PRODUCE UNDESIRABLE BY-PRODUCTS.

ALSO, PRECISE CONTROL OF THE MOLAR RATIO OF SO3 TO ORGANIC IS ESSENTIAL BECAUSE ANY EXCESS SO3, DUE TO ITS REACTIVE NATURE, CONTRIBUTES TO SIDE REACTIONS AND BY-PRODUCT FORMATION.

Air supply system

• Process requires Dry and cool air .• Air should be deficient in any kind of

disturbance• Control valves sort out disturbance problems• Air chiller cools the filtered air• Regenerated air can be recycled

Air supply system

Sulfur feed sysytem

• Control of sulfur to sulfur burning unit is important since that is going to effect mole ratio in main unit

• Sulfur feed system ensures that.• Melting of sulfur takes place here• Entire sulfur feed system is jacketed

considering freezing point of sulphur is 112.60 C.

Sulfur burning unit

• Consist of atomized sulfur burning.• Sulfur dioxide leaving burner is cooled to 4200 C & is

passed through vanadium pentoxide catalytic converter where SO2 is converted to SO3 with 99 % efficiency.

• SO3 is initially cooled in a double pipe cooler by regenerated air.

• Finally cooled by heat exchanger to ambient temperature.

• Inlet mist eliminator eliminates any residual oleum.

Falling Film Reactor

Common Types

Annular Falling Film ReactorMultitube Falling Film

Reactor

• It employs interchangeable organic metering flanges.

• The mole ratio control is maintained on a micro scale throughout the sulfonator.

• Cooling jackets on the reactor remove most of the heat of the reaction.

• The additional recycle system is a huge benefit.

• The cooling process reduces the amount of time of holding sulfonic acid at elevated temperatures.

• It consists of a number of vertical tubes as arranged in a shell and tube heat exchanger

• The tubes are generally 25mm internal diameter and about 6m in length.

• Generally a reactor with 70 tubes would have a capacity of about 3 tonnes of surfactant per hour.

• The residence time from the top of the reactor to the neutralizer is between 2-3 minutes.

Features of a FFR

• Various configurations of Feedstock entry.

• Thin distribution of liquid olefin to prevent localized overheating.

• Short residence time owing to its instantaneous reaction completion.

Points to Remember• Temperature gradient must be sufficent to control the extremely vigorous intial exotherm to avoid charring.

• Air temperature should be below olefin feed.

• Film thickness has to be maintained in the order of (0.001-0.01 inches)

• Mixture of air and S03 should contain 2%-4% of S03

• Here stoichometry plays a very significant role.

EFFECT OF MOLE RATIOS ON 1,4 DIOXANE CONTENT

SO3 absorber

• Is capable of treating the total output from the SO3 generation system to form 98% sulfuric acid.

• It is a convenience in plant startup , shutdown and product changeover. It is also recommended in situations where frequent power failures can interrupt production.

• Generally used when alcohol feedstock are available in plant.

Neutralizer

• The neutralizer combines sulfonic acid or organo-sulfuric acid with a neutralizing agent, additives, and dilutent (water).

• A recycle loop circulates neutral slurry through a heat exchanger to remove heat of neutralization, mixing and pumping.

• Buffer is added to maintain pH.

Effluent Gas Treatment System

References

• Kirk & othmer , 3rd edition• www.chemithon.com• www.ballestra.org• www.google.com ( Images )• Chemistry and technology of surfactants by

Richard farn

THANK YOU