The document discusses advancements in gas-liquid operations, focusing on techniques such as extractive distillation, gas absorption, and various scrubber designs. It highlights the importance of optimizing equipment and processes to enhance separation efficiency and reduce energy consumption. Additionally, it addresses limitations in traditional methods and presents new approaches for improved mass transfer and operational effectiveness.

1. CURRENT ADVANCEMENT IN DIFFERENT
GAS-LIQUID OPERATIONS

2. CONTENT
• Introduction
• Gas Liquid operation equipment
• Extractive distillation
• Advances in Gas Absorption
• High efficiency venturi scrubber
• Advances in Diffusion
• Advances in Stirred Tanks
• Advances in Distillation
• Advances in Venturi Scrubber

3. INTRODUCTION
• Gas-liquid operations are one of the mass
transfer operation in which two immiscible
phases (gas & liquid) are in direct contact.
• Different Gas-Liquid operations :
1. Distillation (fractional distillation)
2. Gas absorption
3. Stripping
4. Humidification
5. Dehumidification

4. GAS-LIQUID OPERATION EQUIPMENT
• Sparged Vessel
• Mechanically Agitated Vessel
• Tray Tower
• Venturi Scrubber
• Wetted Wall Tower
• Spray Tower
• Packed Tower
• Distillation Column

5. EXTRACTIVE DISTILLATION
• In most separation systems, the predominant non ideality
occurs in the liquid phase because of molecular
interactions.
• Azeotropic and low-relative-volatility mixtures are often
present in the separating industry, and their separation
cannot be realized by conventional distillation.
• Extractive distillation is then a suitable widely used
technique for separating azeotropic and low-relative-
volatility mixtures in the pharmaceutical and chemical
industries.
• Given an azeotropic mixture A-B (with A having a lower
boiling temperature than B does), an entrainer E is added
to interact selectively with the original components and
alter their relative volatility, thus enhancing the original
separation.

6. EXTRACTIVE DISTILLATION
• Extractive distillation differs from azeotropic distillation by
the fact that the third-body solvent E is fed continuously in
another column position than the feed mixture.
• Extractive distillation has been studied for many decades,
with a rich body of literature. Some main subjects studied
include column with all possible configurations; process
operation polices and strategy; process design, synthesis,
and optimization; determination of separation sequencing;
entrainer design and selection; feasibility studies; and so
on.
• Feasibility studies also contribute to a better understanding
of complex unit operations such as batch extractive
distillation (BED).

7. ADVANCES IN GAS ABSORPTION
• Micro porous hollow fiber modules offer a larger area per
volume between gas and liquid than that commonly
encountered in packed towers.
• This larger area can be sustained at very low flows, where
packed towers will not be loaded, and at very high flows,
where packed towers will flood.
• As a result, the modules offer the potential of faster mass
transfer. This potential can be compromised by the
resistance to mass transfer of the membrane itself, a
resistance which is increased if the liquid wets the
membrane.
• The results presented in this two-part series show when
the advantage of the increased area is greater than the
disadvantage of the membrane resistance.

8. HIGH EFFICIENCY VENTURI SCRUBBER
• A high efficiency, compact, and
cost effective scrubber is well
suited for a broad range of
applications. Particulates
removal, fumes removal, and
removal of sulphur oxides and
obnoxious gases are
accomplished with less energy
consumption than other type
of scrubbers. Scrubbers are
available in stainless steel, c.
S., FRP and other plastics.

9. HIGH EFFICIENCY VENTURI SCRUBBER
• High Efficiency Venturi Scrubber is a most energy
efficient and compact scrubber design developed
through extensive research and testing. Using a
horizontal flow Venturi and an intensive water
distribution system to scrub the contaminated gases
followed by separation of the scrubbing water in a
cyclonic separator, this model has been shown in field
tests to out performance other competitive scrubbers
by a margin of 2:1 ratio in term of outlet loading when
operating on same conditions. Removal of SO2, HCl,
and other acidic gases are accomplished with the use
of alkalinic solution for scrubbing.

10. ADVANCES IN DIFFUSION
• There are some limitations of the Fick's law for
describing diffusion .
• It is argued that the Maxwell-Stefan formulation
provides the most general, and convenient,
approach for describing mass transport which
takes proper account of thermodynamic non-
idealities and influence of external force fields.
• Furthermore, the Maxwell-Stefan approach can
be extended to handle diffusion in macro- and
micro porous catalysts, adsorbents and
membranes.

11. ADVANCES IN STIRRED TANKS
• Effects of mechanical and hydrodynamic forces on cells
of the microalga Porphyridium cruentum are reported
for aerated cultures in stirred vessels.
• The specific rate of cell death varied linearly with the
specific interfacial area, suggesting the importance of
bubble-cell contacting in the damaging process.
• At low rates of mechanical agitation, bubble break-up
at the culture surface was the predominant cause of
damage.
• In contrast, at higher agitation intensities, cell damage
was caused predominantly by hydrodynamic stress in
bulk turbulent flow.

12. ADVANCES IN DISTILLATION
• The industrial production of anhydrous bioethanol requires
energy demanding distillation steps to overcome the
azeotropic behavior of the ethanol–water mixture. In spite
of the recent developments in pervaporation and
adsorption with molecular sieves, the large scale
production is still dominated by extractive and azeotropic
distillation as the separation technology of choice.
• This study proposes novel distillation technologies for
enhanced bioethanol dehydration, by extending the use of
dividing-wall columns (DWC) to energy efficient extractive
distillation (ED) and azeotropic distillation (AD). Notably,
DWC is one of the best examples of proven process
intensification technology in distillation, as it allows
significantly lower investment and operating costs while
also reducing the equipment and carbon footprint.

13. ADVANCES IN DISTILLATION
• For both ED and AD cases a classic sequence of two
distillation columns and the alternative based on DWC
are optimized using the state of the art sequential
quadratic programming (SQP) method. A mixture of
85 mol.% ethanol is dehydrated using ethylene glycol
and n-pentane as mass separating agents in an
extractive and azeotropic distillation setup,
respectively. The results of the rigorous simulations
performed in Aspen Plus show that energy savings of
10–20% are possible for the novel process
intensification alternatives based on DWC, while using
less equipment units as compared to the conventional
ED and AD configurations.

14. ADVANCES IN VENTURI SCRUBBER
• Accurately predicting and rationally using pressure drop are very
important in optimizing the design of a Venturi scrubbers and
reducing energy consumption.
• Experimental results show that diverging section will recover a
considerable part of energy, so it′s incorrect to consider that
pressure recovery in diverging section can compensate for frictional
pressure drop.
• In this model, through theoretical analysis, considering gas frictional
pressure drop and pressure regain in diverging section due to
droplet′s deceleration, a simple and accurate model for the
prediction of overall pressure drop in Venturi scrubbers is deduced.
• Calculation data are found in good (agreement) with that of
experiment.
• Comparison is made experimentally with predictions of pressure
drop for Venturi scrubber between presented model, modified
Calvert model and Yung model.