The following specification particularly describes the invention and the manner in which
it is to be performed.
FIELD OF THE INVENTION:
The present invention relates to a process for desulfurization of fuels or organics. More
particularly, the present invention relates to a multiphase process for desulfurization of
fuels or organics using hydrodynamic cavitation through in situ generation of oxidizing
species e.g. OH. radicals which react with the sulfur moiety resulting in removal of sulfur
from the organic phase.
BACKGROUND AND PRIOR ART:
For many years, growing concerns over environmental pollution caused by the presence
of sulfur-containing compounds in hydrocarbon-based fuels such as diesel, gasoline, and
kerosene has provided impetus for the development of desulfurization technology. A high
level of sulfur in fuels is undesirable due to the formation of SOx from the combustion of
sulfur-containing compounds. The existing norms in transportation fuels such as gasoline
and diesel require sulfur below 30 and 15 ppm respectively. The existing methods such as
hydrodesulfurization have limitations in bringing sulfur levels to meet desired norms and
other methods such as adsorption, oxidative desulfurization or biodesulfurization have
not been satisfactory in general for commercial practice. The use of fuels for Fuel Cell is
limited due to issues pertaining to sulfur content in fuels as sulfur is a poison to the
catalyst. Many processes employing organics such as terpentines also require effective
removal of sulfur compounds.
Thus, effective removal of sulfur from organics, in general and fuels, in particular, is a
serious challenge for existing treatment technologies, especially in transportation fuels
due to stringent government regulations and also due to applications in Fuel Cell that
requires sulfur well below 1 ppm to avoid catalyst poisoning. Solving these problems can
also help in enhancing performance of processes that use organics and/or fuels containing
sulfur. The existing methods can be classified as:
a) Hydrodesulfurization process that requires use of hydrogen at high temperatures and
pressures (Temp up to 400o C and pressures up to 70 atm)
3
b) Oxidation process that requires specialized catalyst for oxidation and requires
oxidation in organic medium. Reaction conditions are also severe in most cases.
c) Adsorption process that requires use of specific adsorbent to transfer sulfur to solid
adsorbent phase from organic phase. Though the process works under mild
operating conditions, its application is severely limited because of low capacity for
sulfur removal.
d) Biodesulfurization is a biological method and not chemical method that works on the
principle of sulfur removal using microorganisms. It has limited commercial
viability due to various process issues.
US8002971 disclosed a processes and systems associated with hydrodynamic cavitationcatalyzed
oxidation of sulfur-containing substances in a fluid. The document also
discloses a method for removing sulfur-containing compounds from a petroleum-based
fluid containing one or more sulfur-containing compounds that are substantially apolar.
However, the invention disclosed in this patent requires presence of at least one oxidizing
agent like hydrogen peroxide, ozone or monosubstitution products of hydrogen peroxide
(i.e., dioxidane), having the chemical formula, ROOH, where R may be an organic group
or an inorganic group.
Article titled “Catalytic desulfurization of diesel fuel with a cavitation mixer” by S. I.
Kolesnikov et al. published in Chemistry and Technology of Fuels and Oils, 2010, 46(1),
pp70-73 reports cavitation activation of catalytic desulfurization of diesel fuels with a
decrease in the residual content of mercaptan sulfur by 2-2.2 times with a simultaneous
decrease in consumption of the catalytic complex by 2 times.
Article titled “A Review on Diesel Fuel Desulfurization by Adsorption Process” by
Seyed Abolhasan Alavi et al. published in International Conference on Chemical,
Agricultural, and Biological Sciences (ICCABS'2014) Oct. 9-10, 2014 Antalya (Turkey)
reports diesel desulfurization by adsorption method.
Article titled “Optimization of diesel fuel desulfurization by adsorption on activated
carbon” by Marko Muzic et al. reports Diesel fuel was desulfurized by adsorption on a
commercial activated carbon in a batch adsorber. Response surface methodology was
applied for optimizing the adsorption process of organic sulfur compounds. The four
factor Box-Behnken design with five center points and two responses was performed and
4
aimed at developing second order polynomial models and to generate the optimum
conditions.
Article titled “Diesel desulfurization using reactive adsorption on metal impregnated
functionalized polymer” by Yogesh P. Koparkar et al. published in Journal Separation
Science and Technology, 2011,46 (10) pp 1647-1655 reports Organosulfur compounds
were removed from commercial diesel by reactive adsorption on metal impregnated
functionalized polymers at ambient temperature and pressure. The equilibrium adsorption
capacities of Ag+ and Cu+ impregnated resins for dibenzothiophene (DBT) are 13
mg/gm and 9.6 mg/gm. Adsorption and desorption cycle studies in a column packed with
Ag+ and Cu+ loaded BSR resin showed intraparticle resistance affecting uptake of the
sulfur compounds. Only 40% of the adsorbed organo-sulfur compounds was recovered by
solvent regeneration using toluene, but complete regeneration of the bed was possible by
simultaneous microwave heating. Density functional theory (DFT) calculations show
stronger interaction between organosulfur compounds and Cu(I) on the polymer resins.
The interaction energy increases with the number of substituents around ‘S’ in the
structure, giving stronger interaction of the metal ions with dialkyl-substituted
dibenzothiophene than monosubstituted and unsubstituted thiophene.
Article titled “Desulfurization of diesel fuels by adsorption via π-complexation with
vapor-phase exchanged Cu(I)-Y Zeolites” by Arturo J. Herna´ndez-Maldonado et al.
published in Journal of American Chemical Society, 2003, reports desulfurization of
diesel fuels by adsorption via π-complexation with vapor-phase exchanged Cu(I)-Y
Zeolites.
PCT Appl. No. 2013054362 discloses device that can generate a strong vortex in the
vortex chamber which significantly enhances rate of reactions and effectiveness of waste
water treatment and use of a vortex diode that uses the cavitation generated by rotational
flows for the treatment of effluent.
The existing methods such as hydrodesulfurization have limitations in deep
desulfurization due to severe process conditions and excessive requirement of catalyst
and energy. Methods such as adsorption, though useful in lowering sulfur from organics,
have limited capacity and have difficulty in commercial application due to these apart
from regeneration problems.
5
Therefore, there is need in the art to develop a desulfurization process which will
overcome prior art problems. Accordingly, the present invention provides a multiphase
process that can work even without employing any catalyst or any external oxidizing
agents like hydrogen peroxide, ozone or monosubstitution products of hydrogen
peroxide. In this invention, the multiphase process, in which organic and aqueous phases
are mixed in a predefined manner and a third vapor phase is allowed to form in the form
of cavities for in situ generation of oxidizing species e.g. OH. for effective removal of
sulfur.
OBJECTIVE OF THE INVENTION:
The main objective of the present invention is to provide a multiphase process for
desulphurization of fuels or organics.
Another objective of the present invention is to provide effective, controlled and selective
removal of sulfur from fuels and any organic stream.
Still another objective of the present invention is to provide process wherein said process
can be combined with other established processes such as oxidation, adsorption for
further process improvements or for cost benefits or both for sulfur removal.
SUMMARY OF THE INVENTION:
Accordingly, the present invention provides a multiphase process for desulfurization of
fuels or organics in which organic and aqueous phases are mixed in a predefined manner
and a third vapor phase is allowed to form in the form of cavities for in situ generation of
oxidizing species such as OH. radicals which react with the sulfur moiety resulting in
removal of sulfur from the organic phase.
In an embodiment, the fuels are selected from gasoline, kerosene, diesel and the like or
mixture thereof containing any amount of sulfur and containing any type of sulfur
compounds- such as mercaptans, thiols, sulfides, thiophene, benzothiophene or mixture
thereof.
In another embodiment, the organics are selected from alcohols, benzene, toluene, octane,
terpentines/ terpenes and the like or mixture thereof containing any amount of sulfur and
6
for any type of sulfur compounds such as mercaptans, thiols, sulfides, thiophene,
benzothiophene etc. or mixture thereof.
In yet another embodiment, the cavitation is performed by using but not limited to
acoustic cavitation or hydrodynamic cavitation and said cavitation is performed in
cavitation reactor(s) which is able to generate suitable level of cavitation e.g. valves,
orifice, venturi, Vortex diodes, acoustic cavitation, laser cavitation, particle cavitation etc.
In still another embodiment, said process may be operated in such a way that controlled
and selective reduction of sulfur is achieved.
In further embodiment, said process may be intensified through use of oxygen or air
during the cavitation or through any such process intensification technique.
In further embodiment, said process may be combined with any established or newer
catalyst or may be combined with other established processes such as oxidation,
adsorption for further process improvements or for cost benefits or both.
BRIEF DESCRIPTION OF THE DRAWINGS:
Figure 1: Typical experimental set-up for hydrodynamic cavitation using different
cavitation devices.
Figure 2: Typical flow chart for removal of sulfur from organics using new cavitation
based process
Figure 3: Typical Flow Chart for Removal of Sulfur from Organics using Process
Integration –Cavitation with Adsorption
Figure 4: Cavitation coupled with adsorption (Adsorbent Shirasagi TAC; 4% loading)
Figure 5: Cavitation coupled with adsorption (Adsorbent Shirasagi TAC: 2% loading)
Figure 6: Deep desulfurization results (a) commercial diesel (b) comparison with other
organics
DETAILED DESCRIPTION OF THE INVENTION:
The invention will now be described in detail in connection with certain preferred and
optional embodiments, so that various aspects thereof may be more fully understood and
appreciated.
7
In view of above, the present invention provides a multiphase process for desulfurization
of fuels or organics in which organic and aqueous phases are mixed in a predefined
manner and a third vapor phase is allowed to form in the form of cavities for in situ
generation of oxidizing species such as OH. radicals which react with the sulfur moiety
resulting in removal of sulfur from the organic phase.
In an embodiment, the present invention provides a process for desulfurization of fuels or
organics comprising the steps of:
a) Mixing organic phase with aqueous phase followed by preparing third vapor
phase by in situ cavitation;
b) Subjecting cavities formed in step (a) to collapse so as to generate in situ
oxidizing species e.g. hydroxyl radicals or even hydrogen peroxide;
c) Subjecting reaction mixture of step (b) to various reaction mechanisms involving
phase transfer for removal of sulfur from the organic phase;
d) Separating the organic phase and aqueous phase to afford treated product devoid
of sulfur content or having sulfur content within desired limits or selectively
removing specific sulfur compounds.
In preferred embodiment, said Step b) is essentially carried out at the temperature ranging
from 27°C to 50°C.
In another preferred embodiment, the amount of aqueous phase i.e. water may be varied
from 1 to 99.99%.
Still in another preferred embodiment, the process involves above distinct stages of
operation which may be performed in a single unit or using multiple units.
The process may additionally be carried out in presence of suitable adsorbent. Preferably,
the suitable adsorbents are selected from clays, zeolites, activated carbon, modified
adsorbents, polymeric adsorbent etc.
Yet in another preferred embodiment, the fuels are selected from gasoline, kerosene,
diesel and the like or mixture thereof containing any amount of sulfur and containing any
type of sulfur compounds such as mercaptans, thiols, sulfides, thiophene, benzothiophene
or mixture thereof.
8
Still yet in another preferred embodiment, the organics are selected from alcohols
specifically octanol, benzene, toluene, octane, terpentines/ terpenes and the like or
mixture thereof containing any amount of sulfur and for any type of sulfur compounds
such as mercaptans, thiols, sulfides, thiophene, benzothiophene etc. or mixture thereof.
Still yet in another preferred embodiment, the cavitation is performed by using but not
limited to acoustic cavitation or hydrodynamic cavitation but not limited to and said
cavitation is performed in cavitation reactor(s) which is able to generate suitable level of
cavitation e.g. valves, orifice, venturi, Vortex diodes, acoustic cavitation, laser cavitation,
particle cavitation etc.
Still yet in another preferred embodiment, said cavitation is hydrodynamic cavitation
used for generating cavities in cavitation reactor such as vortex diode which drastically
reduce or even eliminate the sulfur from organics and fuels.
In one embodiment, said process may be operated in such a way that controlled and
selective reduction of sulfur is achieved.
In another embodiment, said process may be intensified through use of oxygen or air
during the cavitation or through any such process intensification technique.
Still in another embodiment, said process may be combined with any established or
newer catalyst for further process improvements or for cost benefits or both.
Yet in another embodiment, said process may be combined with other established
processes such as oxidation, adsorption for further process improvements or for cost
benefits or both.
Still yet in another embodiment, after separation of organic phase and aqueous phase,
said aqueous phase can be used/ recycled for further use.
The intermittent steps can also be appropriately modified in combination with other
established methods such as adsorption using suitable adsorbent- e.g. cavitation coupled
with adsorption or cavitation followed by adsorption; oxidation or such methods for
further improvements, as and when required.
Figure 1 depicts typical experimental set-up for hydrodynamic cavitation using different
cavitation devices.
Figure 2 depicts typical flow chart for removal of sulfur from organics using new
cavitation based process.
9
Figure 3 depicts typical flow chart for removal of sulfur from organics using process
integration –cavitation with adsorption.
Figure 4 depicts cavitation coupled with adsorption (Adsorbent Shirasagi TAC; 4%
loading).
Figure 5 depicts cavitation coupled with adsorption (Adsorbent Shirasagi TAC: 2%
loading).
Figure 6 depicts results of sulfur removal using commercial diesel as solvent and
comparison with different solvents.
A novel approach is developed for desulfurization of fuels or organics without use of
catalyst. In this process, organic and aqueous phases are mixed in a predefined manner
under ambient conditions and passed through a cavitating device. Vapor cavities formed
in the cavitating device are then collapsed which generate (in-situ) oxidizing species
which react with the sulfur moiety resulting in the removal of sulfur from the organic
phase. In this work, vortex diode is used as a cavitating device. Three organic solvents (noctane,
toluene and n-octanol) containing known amount of a model sulfur compound
(thiophene) up to initial concentrations of 500 ppm are used to verify the proposed
method. A very high removal of sulfur content to the extent of 100% is demonstrated.
The nature of organic phase and the ratio of aqueous to organic phase are found to be the
most important process parameters. The results are also verified and substantiated using
commercial diesel as a solvent. The developed process has great potential for deep
desulfurization of various organics, in general, and for transportation fuels, in particular.
Inventor present a new process based on hydrodynamic cavitation for deep
desulfurization of fuels and organics without employing any catalyst and using mild
operating conditions. Thiophene is chosen as a model sulfur compound mainly due to
limitation of conventional oxidation processes in its removal. Sulfur containing organic
phase is mixed with water under ambient conditions and passed through a vortex diode.
Vapor cavities are allowed to form in the diode and get transported to the downstream
region where these cavities collapse. The cavity collapse generates localized very high
pressure and temperature as well as hydroxyl radicals. Interaction of hydroxyl radicals
with sulfur compound under these locally extreme conditions result in removal of sulfur
from the organic phase without any catalyst under apparently ambient conditions of bulk.
10
The process block diagram along with schematic of experimental set-up is given in Figs.2
and 1 respectively. The thiophene containing organic solvent was mixed with measured
quantity of water to generate two phase mixtures with organic solvent volume fraction in
the range of 2.5% to 10%. This mixture is passed through vortex diode (at pressure drop
across diode as 0.5 bar and 2 bar with flow rate of ~330 and 680 LPH respectively). The
sulfur content in organic phase, in ppm (obtained by separating organic layer from the
treated mixture) is monitored as a function of time.
Initial experiments are carried out to identify point of cavitation inception. Pressure drop
measurements as a function of flow rate of two phase mixture (organic phase and water)
are carried out. The cavitation inception can be identified from the deviation of measured
pressure drop from the usual square law (ΔP proportional to square of flow rate or mean
velocity). It is established that for the case of octanol – water mixture (up to 10% volume
percent of octanol), the cavitation inception occurs just before the pressure drop across
vortex diode reaches 0.5 bar. In order to establish that sulfur removal is because of
hydrodynamic cavitation and not because of vigorous contact with aqueous phase, the
results of stirred tank experiments are also compared. The results confirm desulfurization
due to hydrodynamic cavitation without employing catalyst. All the further experiments
are carried out at two values of pressure drop across vortex diode (0.5 bar and 2 bar).
Hydrodynamic cavitation is known to generate hydroxyl radicals- an active oxidant. A
plausible mechanism for the removal of sulfur would require cleavage of the sulfur bond
with the attack from the oxidant and release of sulfur dioxide. Alternatively, it can also
form other oxidation products such as sulfones that would go in the aqueous phase,
thereby effecting sulfur removal. A number of other possibilities such as formation of
SO2, HSO3, H2SO4 etc. may also be listed. No change in the pH of the aqueous solution is
observed during or after hydrodynamic cavitation experiments, indicating that formation
of acid or acidic species may not occur though possibility of sulfones formation does
exist. FTIR analysis of the aqueous samples, however, indicated no appreciable presence
of sulfones in the aqueous phase. According to the literature reports, mechanisms in the
case of oxidative desulfurization in presence of various catalysts such as hydrogen
peroxide and other acid catalysts involves reaction of hydrogen peroxide with the acid
resulting into formation of acid peroxide which subsequently reacts with the organic
11
sulfur resulting into formation of sulfone or sulfoxide. Otsuki et al., (2000) reported
formation of sulfones in the organic phase during oxidative desulfurization. The
sulfone/sulfoxide, thus formed, can be extracted in different solvents. It is important to
note that the authors indicated difficulty in oxidising thiophene at 50 0C due to low
electron density though benzothiophne or dibenzothiophene can be easily oxidised using
hydrogen peroxide and formic acid mixture as catalyst. Thus, in the developed method,
removal of organic sulfur is possible by both mineralization as well as oxidation
mechanism. However, since the process here does not employ acid catalyst, the
contribution of later mechanism may not be significant. The role of solvent can be
viewed predominantly as a facilitator in oxidative interfacial reactions through effective
transfer of sulfur moiety in cavities that provide predominantly oxidising species.
Pressure drop across the vortex diode or for that matter any cavitating device, is an
important parameter that contributes towards the extent of cavitation. The number density
of cavities and effective intensity of cavity collapse are governed by pressure drop across
cavitating devices. As mentioned earlier, the pressure drop is varied in the range of 0.5 to
2 bar across the vortex diode. The effect of pressure drop was found to be rather
negligible, especially at low values of organic to aqueous phase volume ratio. It was also
observed that sulfur removal was generally better when initial sulfur concentration was
low for high organic phase volume as shown in the examples below. The trend depends
on nature of organic solvent and ratio and a very high removal close to 100 % can be
obtained at low organic fraction of 2.5%. In the developed process, there are two distinct
liquid phases viz. aqueous and organic (containing sulfur compounds). Influence of
nature of organic phase is expected to be important. Realized cavities and cavity collapse
intensities are expected to vary with respect to the nature of organic phase and volume
ratio of organic to aqueous phase. Experiments are therefore carried out for different
organic solvents and using different volume ratios of organic to aqueous phase. It can be
seen that the removal of sulfur compounds is drastically different with different organic
phases. A very high removal of sulfur is observed with n-octanol compared to other
solvents.
It is instructive to evaluate the impact of the process from commercial application point
of view. For this purpose, a commercial diesel is tested for the removal of sulfur12
thiophene. The commercial diesel had initial sulfur content of 30 ppm (probably in the
form of refractory sulfur compounds). A known amount of sulfur using thiophene is
added in this diesel and the effect of cavitation process was studied for pressure drop and
for the extent of sulfur removal. The results for the two different pressure drop conditions
and using an intermediate organic to aqueous ratio (Organic phase, 6.5%) are shown in
Figure 6(a) along with a comparison with other organic solvents (Fig. 6(b)). The results
indicated a very high removal of sulfur even from the commercial diesel which is a
mixture of aliphatic and aromatic organic compounds. The process is advantageous, cost
effective, has many implications for future developments and may further be intensified
using a number of ways e.g. aeration, use of catalyst etc.
A new multiphase non-catalytic process is developed for deep desulfurization of fuels or
organics using hydrodynamic cavitation with vortex diode as a cavitating device. The
process can completely remove thiophene sulfur from organic streams with considerable
ease of operation and under mild operating conditions. Deep desulfurization of fuels to
the extent of 100% was demonstrated for thiophene in model fuel. The removal
efficiency depends strongly on nature of organics e.g. alcohols, aromatic solvents,
aliphatic solvents or their mixtures apart from organic to aqueous ratio, pressure drop,
and initial concentration of sulfur.
The aqueous phase used in the proposed method can be recycled after removing a purge
stream (with corresponding make-up water). Hydrodynamic cavitation usually improves
performance with scale-up and hence the proposed method can be effectively
implemented for large scale deep desulfurization operations.
The following examples, which include preferred embodiments, will serve to illustrate
the practice of this invention, it being understood that the particulars shown are by way of
example and for purpose of illustrative discussion of preferred embodiments of the
invention.
Examples:
Example 1: Hydrodynamic Cavitation for Removal of Sulfur from Real Diesel:
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000 LPH flow through the section. A storage tank of 50 liters was used for the
13
storage of diesel to be desulfurized. A real diesel solution containing 10% diesel v/v and
90% water was used for the treatment. Using different conditions for the pressure drop
through the disclosed invention, a reduction of ~28 % was obtained in the sulfur content
for initial sulfur of ~ 30 ppm in about 1 h using pressure drop of 2 bar(Table-1)
Table-1. Hydrodynamic Cavitation of Real Diesel (Δp=2 bar; Flow rate=700 LPH)
Time, min Temperature, 0C Sulfur content, ppm % Sulfur removal
0 34 29 0
60 34 20.95 27.7
Example 2: Hydrodynamic cavitation for Removal of Sulfur from Diesel containing
Thiophene:
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000 LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A real diesel solution containing 10% diesel v/v and
90% water was used for the treatment. A known quantity of Sulfur in the form of
Thiophene (300 ppm) was added to the mixture and the total sulfur content was 323 ppm.
Using the same conditions of Example-1, for the pressure drop through the disclosed
invention device, a sulfur reduction of ~80% was obtained in 1h and 96 % reduction was
obtained in the sulfur content in about 3 h (Table-2).
Table-2. Hydrodynamic Cavitation at Δp=2 bar and Flow rate=700 LPH
Time, min Temperature, 0C Sulfur content, ppm % Sulfur removal
0 34.5 322 0
60 44.8 59.33 81.6
90 46 30.01 90.7
120 46.4 23.59 92.7
150 46.6 14.95 95.4
180 46.8 14.02 95.6
Example 3
14
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A synthetic fuel comprising thiophene in n-octane was
used. Initial thiophene concentration was 305ppm & 235ppm for a pressure drop of 2bar
and 0.5 bar respectively. An organic phase to aqueous phase volume ratio of 1:9 was
used. Experiments were carried out at ambient temperature and the temperature was
controlled using cooling arrangement. Sulfur reduction of 17% and 23% was obtained
after 2h for a pressure drop of 2bar and 0.5 bar respectively.
Example 4
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A synthetic fuel comprising thiophene in n-octanol was
used. Initial thiophene concentration was 220ppm & 235ppm for a pressure drop of 2bar
and 0.5 bar respectively. An organic phase to aqueous phase volume ratio of 1:9 was
used. Experiments were carried out at ambient temperature and the temperature was
controlled using cooling arrangement. Sulfur reduction of 62% and 72% was obtained
after 2h for a pressure drop of 2bar and 0.5 bar respectively. The results are shown in
Table-3.
Table-3: Desulfurization results with n-octanol-water system (1:9 v/v).
Time(min)
%S removal
ΔP=2 bar ΔP=0.5bar
30 26 30
60 40 50
90 52 67
120 62 72
15
Example 5
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A synthetic fuel comprising thiophene in toluene was
used. Initial thiophene concentration was 240ppm & 285ppm for a pressure drop of 2bar
and 0.5 bar respectively. An organic phase to aqueous phase volume ratio of 1:9 was
used. Experiments were carried out at ambient temperature and the temperature was
controlled using cooling arrangement. Sulfur reduction of 5% and 15% was obtained
after 2h for a pressure drop of 2bar and 0.5 bar respectively. The results are shown in
Table-4.
Table-4: Desulfurization results with toluene-water system (1:9 v/v).
Time(min)
%S removal
ΔP=2 bar ΔP=0.5bar
30 0.42 5.81
60 1.68 11.85
90 4.72 13.01
120 5 15
Example 6
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A synthetic fuel comprising thiophene in n-octane was
used. Initial thiophene concentration was 85 ppm & 75ppm for a pressure drop of 2bar
and 0.5 bar respectively. An organic phase to aqueous phase volume ratio of 1:9 was
used. Experiments were carried out at ambient temperature and the temperature was
controlled using cooling arrangement. Sulfur reduction of 27% and 29% was obtained
after 2h for a pressure drop of 2bar and 0.5 bar respectively. The results are shown in
Table-5.
16
Table-5: Desulfurization results with n-octane-water system (1:9 v/v).
Time(min)
%S removal
ΔP=2 bar ΔP=0.5bar
30 12.7 7.78
60 14 18.1
90 21.7 22.89
120 26.4 28.81
Example 7
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A synthetic fuel comprising thiophene in n-octanol was
used. Initial thiophene concentration was 105ppm & 65ppm for a pressure drop of 2bar
and 0.5 bar respectively. An organic phase to aqueous phase volume ratio of 1:9 was
used. Experiments were carried out at ambient temperature and the temperature was
controlled using cooling arrangement. Sulfur reduction of 78% and 64% was obtained
after 2h for a pressure drop of 2bar and 0.5 bar respectively. The results are shown in
Table-6.
Table-6: Desulfurization results with n-octanol-water system (1:9 v/v).
Time(min)
%S removal
ΔP=2 bar ΔP=0.5bar
30 44.82 28.02
60 65.73 44.23
90 71.90 57.14
120 77.5 64.49
Example 8
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
17
providing 1000LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A synthetic fuel comprising thiophene in toluene was
used. Initial thiophene concentration was 85ppm & 100ppm for a pressure drop of 2bar
and 0.5 bar respectively. An organic phase to aqueous phase volume ratio of 1:9 was
used. Experiments were carried out at ambient temperature and the temperature was
controlled using cooling arrangement. Sulfur reduction of 12% and 15% was obtained
after 2h for a pressure drop of 2bar and 0.5 bar respectively. The results are shown in
Table-7.
Table-7: Desulfurization results with toluene-water system (1:9 v/v).
Time(min)
%S removal
ΔP=2 bar ΔP=0.5bar
30 4.8 3
60 4.25 4.04
90 4.5 5.14
120 11.65 14.71
Example 9
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A synthetic fuel comprising thiophene in n-octane was
used. Initial thiophene concentration was 220ppm & 235 ppm for a pressure drop of 2bar
and 0.5 bar respectively. An organic phase to aqueous phase ratio of 1:40 was used.
Experiments were carried out at ambient temperature and the temperature was controlled
using cooling arrangement. Sulfur reduction of 87% and 89% was obtained after 2h for a
pressure drop of 2bar and 0.5 bar respectively. The results are shown in Table-8.
Table-8: Desulfurization results with n-octane-water system (1:40 v/v).
Time(min)
%S removal
ΔP=2 bar ΔP=0.5bar
18
30 38.12 34.2
60 62.07 60.61
90 77.22 77.43
120 86.08 88.87
Example 10
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A synthetic fuel comprising thiophene in n-octanol was
used. Initial thiophene concentration was 195ppm & 210 ppm for a pressure drop of 2bar
and 0.5 bar respectively. An organic phase to aqueous phase volume ratio of 1:40 was
used. Experiments were carried out at ambient temperature and the temperature was
controlled using cooling arrangement. Sulfur reduction of 97% and 100% was obtained
after 2h for a pressure drop of 2bar and 0.5 bar respectively. The results are shown in
Table-9.
Table-9: Desulfurization results with n-octanol-water system (1:40 v/v).
Time(min)
%S removal
ΔP=2 bar ΔP=0.5bar
30 64.1 58.78
60 88.69 93.38
90 96.12 100
120 97.38 100
Example 11
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A synthetic fuel comprising thiophene in toluene was
used. Initial thiophene concentration was 240ppm & 220 ppm for a pressure drop of 2bar
and 0.5 bar respectively. An organic phase to aqueous phase volume ratio of 1:40 was
used. Experiments were carried out at ambient temperature and the temperature was
19
controlled using cooling arrangement. Sulfur reduction of 47% and 35% was obtained
after 2h for a pressure drop of 2bar and 0.5 bar respectively. The results are shown in
Table-10.
Table-10: Desulfurization results with toluene-water system (1:40 v/v).
Time(min)
%S removal
ΔP=2 bar ΔP=0.5bar
30 15.1 5.38
60 24.82 17.23
90 38.73 26.44
120 47.01 35.26
Example 12
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A synthetic fuel comprising thiophene in n-octane was
used. Initial thiophene concentration was 85ppm & 80 ppm for a pressure drop of 2bar
and 0.5 bar respectively. An organic phase to aqueous phase volume ratio of 1:40 was
used. Experiments were carried out at ambient temperature and the temperature was
controlled using cooling arrangement. Sulfur reduction of 94% and 92% was obtained
after 2h for a pressure drop of 2bar and 0.5 bar respectively. The results are shown in
Table-11.
Table-11: Desulfurization results with n-octane-water system (1:40 v/v).
Time(min)
%S removal
ΔP=2 bar ΔP=0.5bar
30 43.57 46.04
60 64.11 63.34
90 81.49 80.70
120 93.93 92.23
20
Example 13
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A synthetic fuel comprising thiophene in n-octanol was
used. Initial thiophene concentration was 135ppm & 75 ppm for a pressure drop of 2bar
and 0.5 bar respectively. An organic phase to aqueous phase volume ratio of 1:40 was
used. Experiments were carried out at ambient temperature and the temperature was
controlled using cooling arrangement. Sulfur reduction of 100% was obtained after 2h for
a pressure drop of 2bar and 0.5bar. The results are shown in Table-12
Table-12: Desulfurization results with n-octanol-water system (1:40 v/v).
Time(min)
%S removal
ΔP=2 bar ΔP=0.5bar
30 89.67 85.29
60 100 100
90 100 100
120 100 100
Example 14
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A synthetic fuel comprising thiophene in toluene was
used. Initial thiophene concentration was 90ppm & 105 ppm for a pressure drop of 2bar
and 0.5 bar respectively. An organic phase to aqueous phase volume ratio of 1:40 was
used. Experiments were carried out at ambient temperature and the temperature was
controlled using cooling arrangement. Sulfur reduction of 34% and 32% was obtained
after 2h for a pressure drop of 2bar and 0.5 bar respectively. The results are shown in
Table-13.
21
Table-13: Desulfurization results with toluene-water system (1:40 v/v).
Time(min)
%S removal
ΔP=2 bar ΔP=0.5bar
30 5.18 --
60 14.43 11.80
90 21.72 21.62
120 34.10 31.18
Example 15
Experimental loop for desulfurization of diesel with disclosed invention was established.
The nominal pipe diameter used was ¾”. The set-up was equipped with pump capable of
providing 1000LPH flow through the section. A storage tank of 50 liters was used for the
storage of fuel to be desulfurized. A synthetic fuel comprising thiophene in diesel was
used. Initial thiophene concentration was 220 ppm & 230 ppm for a pressure drop of 2bar
and 0.5 bar respectively. An organic phase to aqueous phase volume ratio of 1:14 was
used. Experiments were carried out at ambient temperature and the temperature was
controlled using cooling arrangement. Sulfur reduction of 81% and 90% was obtained
after 2h for a pressure drop of 2bar and 0.5 bar respectively. The results are shown in
Table-14.
Table-14: Desulfurization results with diesel-water system (1:14 v/v).
Time(min)
%S removal
ΔP=2 bar ΔP=0.5bar
60 69.25 74.37
90 77.09 87.03
120 81.28 89.80
Example 16
Comparison of the solvents
22
Fig.6 summarizes the effect of nature of solvent (n-octane, n-octanol and toluene along
with commercial diesel) for the case of higher initial sulfur concentration (Initial
Concentration of Thiophene: 285 ppm in toluene and 235 ppm in all other solvents) and
using low pressure drop condition of 0.5 bar.
Advantages of invention:
1. The use of novel process, reaction, reactors and reactor combinations and method can
offer effective, controlled and selective removal of sulfur from fuels and any organic
stream.
2. The developed process does not require high temperature and pressure conditions of
conventional hydrodesulfurization processes and operates at nearly ambient
conditions. The developed process also operates without use of any catalyst.
3. The process can be combined with other established processes such as oxidation,
adsorption for further process improvements or for cost benefits or both.

We claim,
1. A multiphase process for desulfurization of fuels or organics comprising the steps
of:
a) Mixing organic phase with aqueous phase followed by preparing third
vapor phase by in situ cavitation;
b) Subjecting cavities formed in step (a) to collapse so as to generate in situ
oxidizing species e.g. hydroxyl radicals or even hydrogen peroxide;
c) Subjecting reaction mixture of step (b) to various reaction mechanisms
involving phase transfer for removal of sulfur from the organic phase;
d) Separating the organic phase and aqueous phase to afford treated product
devoid of sulfur content or having sulfur content within desired limits or
selectively removing specific sulfur compounds followed by recycling
said aqueous phase for further use.
2. The process is claimed in claim 1, wherein said step (b) is essentially carried out
at the temperature ranging from 27°C to 50°C.
3. The process is claimed in claim 1, wherein said steps a-d are performed in a single
unit or using multiple units.
4. The process is claimed in claim 1, wherein said aqueous phase is water and
amount of said water is varied from 1 to 99.99%.
5. The process is claimed in claim 1, wherein said process is additionally carried out
by in presence of suitable adsorbent, wherein said adsorbent is selected from
clays, zeolites, activated carbon, modified adsorbents, polymeric adsorbent.
6. The process is claimed in claim 1, wherein said fuels are selected from gasoline,
kerosene, diesel or mixture thereof and containing sulfur compounds or mixture
thereof.
7. The process is claimed in claim 1, wherein said organics are selected from
alcohols e.g. octanol, benzene, toluene, octane, terpentines/ terpenes or mixture
thereof containing sulfur compounds or mixture thereof.
8. The process is claimed in claim 1, wherein said cavitation is performed by using
acoustic cavitation or hydrodynamic cavitation, said cavitation is performed in
cavitation reactor(s) wherein said cavitation reactor is Vortex diodes.
24
9. The process is claimed in claim 1, wherein said process is carried out alone or in
combination with oxidation, adsorption.
10. The process is claimed in claim 1, wherein said process is carried out without
catalyst.