Title of Invention

TREATMENT PROCESSES TO REMOVE HYDROGEN SULPHIDE AND MERCAPTAN SULPHUR FROM USED COMPRESSOR OILS FOR SALVAGING AND RECYCLING

Abstract A process for removal of H2S and Mercaptans sulphur from compressor oil comprising: adding adsorbents under heating in presence of nitrogen bubbling for a certain period of time with stirring; subjecting the oil thus obtained to the step of filtration.
Full Text


FIELD OF INVENTION:
This invention relates to treatment processes to remove Hydrogen Sulphide and
Mercaptan Sulphur from used compressor oils for salvaging and recycling.
BACKGROUND OF INVENTION:
Heavy water play crucial role in the generation of nuclear energy and is used as
moderator and coolant in the reactors using Uranium as fuel. The viability of
producing heavy water depends on the isotopic mass transfer rate and chemical
exchange process involving hydrogen containing compounds such as H2, H2O,
H2S, NH3, CH4 etc.. For acceptable isotopic mass transfer rate the bonds of the
above molecules should be made labile. Among available Hydrogen containing
molecules the bonds of O-H, S-H and N-H are so much labile that bond braking
and making processes occur in isotopic exchange reaction without any catalyst
at any temperature. Hence the exchange processes of H2S-H2O and NH3-H2O
are preferred, as the reaction does not involve catalyst and can be conducted at
any desired temperature. Thus heavy water production utilizes dual temperature
exchange process of H2S and water for extracting Deuterium from water up to
15% and subsequent enrichment to reactor grade through vacuum distillation.
Thus Hydrogen Sulphide is used in large quantities as carrier gas, which is highly
toxic and corrosive in nature. Hydrogen Sulphide gas booster compressors are
used in the exchange units to make up the pressure loss for circulating the H2S
gas through exchange unit towers. A dedicated seal oil system is provided for
supplying seal oil to the compressor seal. The seal oil is likely to get
contaminated with H2S over a period of time due to diffusion of gas into the seal
oil and hence mixing of seal oil with lube oil result in the contamination of lube oil


also. The lube oil is supposed to be free from H2S gas, as any traces of H2S in
lube oil is critical and will effect the bearings made of white metal causing
pressure loss to the exchange towers. In such cases, the contaminated oil
cannot be used in the lube oil system and has to be rejected. The rate of
rejection may be around 200 to 400 Liters per day which cannot be reused and
the oil is difficult to dispose off due to the toxicity and environmental problems of
H2S gas. Thus, large quantities of oil is to be rejected due to the contamination
of H2S gas which is not economically feasible. When H2S gas dissolves in oil it
causes formation of Mercaptans also.
This patent covers reclamation and regeneration of used oil. During the process
of dissolution of H2S in oil, there is a possibility of elemental sulphur and
Mercaptan sulphur formation due to the oxidation caused by ingressed oxygen.
The formation of Mercaptan Sulphur and other forms of Sulphur cause corrosion
and damage to the copper containing components.
AB Nynaes Petroleum in their publication WO 071363401-A1. and Marine oil
technology in their publication EP 1059988-B1, deals with general lubricants not
specific to oil contaminated with H2S gas. Corex Technologies in their publication
WO9600273-A1 process for the reclamation of used lubricating oils. The
following patents which are reported, deal with general reclamation methods for
lubricating oils, light Petroleum distillates and LPG. They are not relevant to the
present patent being filed.
Nalco chemical company in their publication EP0617991B1, A1 & US6082982
'On method of recovering oil from waste oil fluids'.
Adfiltech US 5330636 'Apparatus for reconditioning of hydrocarbon fluids'.
Opcon Inc US4769147 'Oil reclamation apparatus'.
Budny, Rick R US 4681660. 'Method and Device for reclaiming fluid lubricants'


Rosser Frank S US 6082982 deals with reclamation of compressor refrigerant.
'CBM oil reclamation systems incorporated US 4515684 oil reclamation process
and apparatus there for.
Separator EC C10M175/00F an improvement process and apparatus for the
reclamation of used lubricating oil.
US Patent no. 5135616 on 'Oil purification deals with packed column method for
collecting and purification of oil for removal of lighter fractions of oil'.
US Patent No. 5332507 deals with recovery of oil from recycling of waste oil
fluids by removing solids and emulsion water.
US Patent No. 6485632B1 'Apparatus and method for waste oil deals with
recovery waste oil to make it suitable as fuel for diesel engine through filtration'.
US Patent No. 5944034 'Apparatus and method for recycling oil laden waste
materials through vapoursing condensation'.
US Patent No. 7022240 'Method and apparatus for on-site treatment of oil and
gas well waste fluids'.
US Patent 6565740 'Process for sweetening of LPG, Light petroleum distillates
by liquid-liquid extraction using metal phthalocyanine sulphonamide catalyst'.
In addition to the above, the following patents have also been referred which
mostly deal with reclamation of combustion engine oils and adopt different
treatment procedures.
WO07136340, US 5330636, GB 318626, GB 284327, US 4769147, US
4681660, US 5314613, US 5135616, US 5332507, US 6139725, US 5824211,
US 5630956, US 5556548, US 5286380, US 5242034, US 5240593, US
4443334, US 4330038, US 4289583, US 4227969, US 4189351, US 5776315
and US 4943352. None of the Patents cited herein above teaches the method of
the present invention.


OBJECT OF THE INVENTION:
An object of this invention is to propose a process for the removal of H2S &
Mercaptan Sulphur from the used compressor oils;
Another object of this invention is to propose a process for the removal of H2S &
Mercaptan Sulphur from the used compressor oils for recycling;
Further, object of this invention is to propose a process for the reclamation and
regeneration of used compressor oils.
SUMMARY OF THE INVENTION:
According to this invention there is provided a process for removal of H2S and
Mercaptans sulphur from compressor oil comprising:
adding adsorbents under heating in presence of nitrogen bubbling for a certain
period of time with stirring;
subjecting the oil thus obtained to the step of filtration.
In accordance with this invention there is also provided a process as claimed in
the proceeding claim wherein 20 wt% of dried molecular sieves 13 X is added to
compressor oil and heated to 90°C with nitrogen bubbling for 2 hours with stirring
are treated with 99.9% electrolytic grade copper powder and the temperature
is increased to 100°C for 2 hrs and then filtered.
Further, in accordance with this invention there is provided a process for removal
of H2S & Mercaptans from compressor oil by heating to a temperature of 90 to
120°C in the presence of electrolytic grade copper powder or mixture of copper
and silver powders


DESCRIPTION OF THE INVENTION:
In petroleum industry, the H2S contamination is usually removed by caustic wash
which is very effective and cheaper but caustic wash cannot remove the
Mercaptans and free sulphur formed during the reaction with H2S gas. Further
alkali treatment may remove the additives which are generally added to improve
the performance of oil. Hence various reclamation processes were studied to
remove the contaminants from oil so as to make it reusable. Keeping in view of
the scaling up of the processes and economy of regeneration, different
adsorbents such as animal charcoal, fullers earth, neutral alumina, molecular
sieves, were tried in different combinations to achieve the goal of removal of H2S
and Mercaptans below the instrument detection level as per the methods given.
With the combination of different adsorbents, the treatment process can be
scaled up continently to suit the batch size by designing columns with proper bed
material as experimented in our processes.
In this process the used oil is heated to 90°C with nitrogen bubbling for 1 to 2
hours and then the oil is treated with electrolyte grade copper powder (20% by
weight) at 120°C and stirring and filtered. The filtered oil is treated with neutral
alumina at temperature of 60 to 70°C filtered. The contaminants like H2S
Mercaptan Sulphur and elemental Sulphur were determined. When the treated oil
is tested, it is found to be free from H2S, Mercaptan and elemental Sulphur.
Experiments were also conducted with mixture of Copper and Silver powders (15
and 5% by weight). There is improvement in the color of the oil and the oil has
become more clear.


The contaminated oil is degassed under vacuum for 2 to 4 hours at 60 to 80°C
with stirring. The oil is then treated with dried animal charcoal (5 to 10%) and
fullers earth (Korvi earth) (5 to 10%) and filtered. The filtered oil is tested for H2S,
merchantman sulphur and elemental Sulphur.
The contaminated oil is bubbled with nitrogen gas at 120, 240, 360 ml/minute for
2 to 4 hours at 80 to 100°C and then treated with animal charcoal (5 to 10%)
followed by fullers earth (5 to 10%)
The contaminated oil is bubbled with nitrogen gas and treated with neutral
alumina followed by animal charcoal and fullers earth
The contaminated oil is treated with molecular sieve 13 X at room temperature to
remove H2S gas and then subsequently treated with neutral alumina, animal
charcoal and fullers earth to remove the Mercaptans, acid contaminants,
moisture and to improve colour. The advantage of using molecular sieve 13X is
to regenerate H2S gas by heating molecular sieves to 150° C. Thus, the H2S gas
is recovered and reused. This process is usefull in a continuous process after
scaling up by using a column with a bed of molecular sieves. The molecular
sieves has got the capability adsorbing 50 g of H2S gas per Kg of molecular
sieves.
The oil is treated with molecular sieve 13 X with stirring and then treated with
electrolytic copper powder at 100°C with stirring for 2 to 4 hours and then filtered.
The filtered oil is treated with animal charcoal (5 to 10%) followed by neutral
alumina (2 to 4%) and fullers earth.
The physical and chemical properties of oil before processing and after
processing by the above methods are determined. The H2S was tested by IP
342/93 method by treatment with Cadmium Sulphate. The qualitative presence of
Mercaptans were determined by ASTM D 4952 (Doctors test). The quantitative


estimation of Mercaptan and H2S were determined by potentionmetric method
using silver-silver sulphide electrode with nitrogen purging and by titrating the oil
sample in a solvent like Isopropanol as per UOP 163-89.
Further, the process of the present invention will be described in greater details
with the help of the examples:
Treatment with Copper, Silver powders and other adsorbent materials
The treatment of the oil by the process given under 3.1, though effective, it
causes oil to become dark in color, and the acid values are comparatively higher
as compared to the other process. Treatment of oil given under 3.2 to 3.6 can
effectively remove the Mercaptans and elemental Sulphur and the process is
safe to handle as the reaction temperature is on lower side.
Example-1
Oil C (Process-1):
100 g of compressed oil containing H2S and Mercaptan is taken in a beaker and
heated to 90°C with Nitrogen bubbling for 2 hours under stirring. The oil is then
treated with 20 g of 99.9% pure electrolytic grade copper powder under stirring.
The temperature of the oil is slowly increased from 90 to 120°C over a period of
one hour and the temperature is maintained at 120°C for 2 hours with stirring. At
the end of 2 hours the stirring is stopped, the oil is allowed to settle and then
filtered hot through a sintered glass crucible (G4) under vacuum. The colour of
the oil is found to be dark brown. The physical and chemical properties of the oil
after treatment are determined and are given in table-1.


Example-2
Oil D (Process-2)
100 g of compressed oil containing H2S and Mercaptan is taken in a beaker and
heated to 90°C with Nitrogen bubbling for 2 hours under stirring. The oil is then
treated with 15 g of 99.9% pure electrolytic grade copper powder and 5 g of
99.9% silver powder under stirring. The temperature of the oil is slowly increased
from 90 to 120°C over a period of one hour and the temperature is maintained at
120°C for 2 hours with stirring. At the end of 2 hours the stirring is stopped the oil
is allowed to settle and then filtered hot through a sintered glass crucible (G4)
under vacuum. The oil is found to be clear and dark brown in colour. The
physical and chemical properties of the oil after treatment are determined and
are given in table-2


Example-3
Oil E (Process-3):
100 g of the compressor oil containing H2S and Mercaptan is taken in a 2 necked
round flask with a paddle for stirring. One neck is connected to a vacuum pump
through a trap. The oil is heated to 60°C under vacuum at 2 mm of Hg for 2 hours
with constant stirring. At the end of 2 hours, 5 g of previously dried animal
charcoal is added slowly for period of 20 minutes through a separating funnel
under stirring maintaining the vacuum and temperature. The stirring is continued
for 30 minutes. 10 g of fullers earth (korvi earth) previously dried for 24 hours at
105°C is added slowly through a separating funnel for 20 minutes under stirring
maintaining temperature and vacuum. The temperature of the oil is increased to
80°C and maintained for 2 hours with stirring. The stirring is stopped after 2
hours and the oil is filtered through a buckner funnel with a filter paper under
vacuum. The physical and chemical properties of the oil is determined and are
given in table-3


Example-4
Oil F (Process-4):
100 g of the compressor oil containing H2S and Mercaptans is taken in a 2
necked round flask with a paddle for stirring. One neck is connected to a nitrogen
cylinder for sparging nitrogen gas. The oil is heated to 80°C under nitrogen
bubbling at the rate of 360 ml/min for 2 hours with constant stirring. At the end of
2 hours, 5 g of previously dried animal charcoal is added slowly for periord of 20
minutes through a separating funnel under stirring maintaining the temperature.
The stirring is continued for 30 minutes, 10 g to fullers earth (korvi earth)
previously dried for 24 hours at 105°C is added slowly through a separating
funnel for 20 minutes under stirring maintaining temperature and Nitrogen. The
temperature of the oil is increased to 90°C and maintained for 2 hours with
stirring. The stirring is stopped after 2 hours and the oil is filtered through a
buckner funnel with a filter paper under vacuum. The physical and chemical
properties of the oil is determined and are given in table-4


Example-5
Oil G (Process-5):
100 g of the compressor oil containing H2S and Mercaptan is taken in a 2 necked
round flask with a paddle for stirring. One neck is connected to a nitrogen
cylinder with flow controller for sparging nitrogen gas. The oil is heated to 80°C
under nitrogen bubbling at the rate of 360 ml/min for 2 hours with constant
stirring. At the end of 2 hours, the 5 g of previously dried neutral alumina is
added slowly for period of 20 minutes through a separating funnel under stirring
maintaining the temperature. The stirring is continued for 30 minutes. 10 g of
fullers earth (korvi earth) previously dried for 24 hours at 105°C is added slowly
for 20 minutes under stirring maintaining temperature and Nitrogen. The
temperature of the oil is increased to 90°C and maintained for 2 hours with
stirring. The stirring is stopped up to 2 hours and the oil is filtered through a
buckner funnel with a filter paper under vacuum. The physical and chemical
properties of the oil is determined and are given in table-5.


Example-6
Oil H (Process-6):
100 g of the compressor oil containing H2S and Mercaptans is taken in a 2
necked round flask with a paddle for stirring. 20 g of previously dried molecular
sieve 13 X is added slowly at room temperature with stirring for a period of 2 to 4
hours. At the end of 4 hours, the oil is filtered. The filtered oil is heated to 80°C
under nitrogen bubbling at the rate of 360 ml/min for 2 hours with constant
stirring. At the end of 2 hours, the 5 g of previously dried neutral alumina is
added slowly for period of 20 minutes through a separating funnel under stirring
maintaining the temperature. The stirring is continued for 30 minutes. 10 g of
fullers earth (korvi earth) dried for 24 hours at 105°C is added slowly for 20
minutes under stirring maintaining temperature and Nitrogen. The temperature of
the oil is increased to 90°C and maintained for 2 hours with stirring. The stirring is

stopped after 2 hours and the oil is filtered through a buckner funnel with a filter
paper under vacuum. The physical and chemical properties of the oil is
determined and are given in table -6.

Example-7
Oil I (Process-7):
100 g of compressed oil containing H2S and Mercaptans is taken in a beaker and
treated with 10 g of molecular sieve 13 X and then heated to 90°C with Nitrogen
bubbling for 2 hours under stirring. The oil is then treated with 20 g of 99.9% pure
electrolytic grade copper powder under stirring. The temperature of the oil is
slowly increased from 90 to 100°C over a period of one hour and the temperature
is maintained at 100°C for 2 hours with stirring. At the end of 2 hours the stirring
is stopped, the oil is allowed to settle and then filtered hot through a sintered
glass crucible (G4) under vacuum. The colour of the oil is found to be brown. The

physical and chemical properties of the oil after treatment are determined. Since
the colour is dark brown and the acid value is high the process adopted under
Example-4 is applied to remove the acids and also to remove any traces of
Mercaptans present in the oil after treatment. The oil is heated to 80°C under
nitrogen bubbling at the rate of 360 ml/min for 2 hours with constant stirring. At
the end of 2 hours, the 5 g of previously dried animal charcoal is added slowly for
period of 20 minutes through a separating funnel under stirring maintaining the
temperature. The stirring is continued for 30 minutes. 10 g of fullers earth (korvi
earth) dried for 24 hours at 105°C is added slowly for 20 minutes under stirring
maintaining temperature and nitrogen sparging. The temperature of the oil is
increased to 90°C and maintained for 2 hours with stirring. The stirring is stopped
after 2 hours and the oil is filtered through a buckner funnel with a filter paper
under vacuum. The physical and chemical properties of the oil is determined and
are given in table-7.





The properties obtained after subjecting H2S contaminated oils to different
treatment processes as compared to fresh oil and H2S saturated site oils are
given in Table-8.
In the model experiments H2S free compressor grade oil is taken and saturated
by bubbling H2S gas and then subjected the oil by the above treatment methods.
The H2S presence is tested by adding cadmium sulphate which did not show any
precipitate indicating the absence of H2S. Similarly Mercaptan free compressor
oil is mixed with known concentrations of Octadecylmercaptan or ethyl
Mercaptan and subjected the oil to the above processes to find out the efficiency
of the method for total removal of Mercaptan as indicated by Doctors test. The
RBOT value of the treated oil is comparable with fresh oil indicating that the
performance additives are not lost or depleted during the treatment. The debris
after removal of impurities can be disposed off by incinerating.

WE CLAIM:
1. A process for removal of H2S and Mercaptans sulphur from compressor oil
comprising:
adding adsorbents under heating in presence of nitrogen bubbling for a certain
period of time with stirring;
subjecting the oil thus obtained to the step of filtration.
2. The process as claimed in claim 1, wherein the said adsorbents are selected
from animal charcoal fullers earth, neutral alumina, molecular sieves, copper
powder, silver powder and mixtures thereof.
3. The process as claimed in claim 1, wherein the oil is heated to a temperature
of 90 to 120°C
4. The process as claimed in claim 1, wherein the nitrogen bubbled for 1 to 2
hours under stirring.
5. The process as claimed in claim 1, wherein nitrogen gas is bubbled at 80°C at
the rate of 360 ml/min for 2 hours and treated with 5 wt% animal charcoal and 10
wt% fullers earth at 90°C and maintaining temperature for 2 hrs and filtration.
6. The process as claimed in claim 5, wherein instead of 5 wt% animal charcoal
5 wt% dried neutral alumina at 80°C is used.
7. The process as claimed in claim 5, wherein 20 wt% of dried molecular sieves
13 X at room temperature is added to the compressor oil under stirring for 4
hours.

8. The process as claimed in the preceeding claims wherein 20 wt% of dried
molecular sieves 13X is added to compressor oil and heated to 90°C with
nitrogen bubbling for 2 hrs with stirring and treated with 99.9% electrolytic grade
copper powder and the temperature is increased to 100°C for 2 hrs and the
filtered.
9. A process for removal of H2S and Mercaptans from compressor oil by heating
to a temperature of 90 to 120°C in the presence of electrolytic grade copper
powder or mixture of copper and silver powders.


ABSTRACT

Title: Treatment processes to remove hydrogen sulphide and mercaptan sulphur
from used compressor oils for salvaging and recycling.
A process for removal of H2S and Mercaptans sulphur from compressor oil
comprising: adding adsorbents under heating in presence of nitrogen bubbling for
a certain period of time with stirring; subjecting the oil thus obtained to the step of
filtration.

Documents:

00766-kol-2008-abstract.pdf

00766-kol-2008-claims.pdf

00766-kol-2008-correspondence others.pdf

00766-kol-2008-description complete.pdf

00766-kol-2008-form 1.pdf

00766-kol-2008-form 2.pdf

00766-kol-2008-form 3.pdf

00766-kol-2008-gpa.pdf

766-KOL-2008-(13-07-2012)-CORRESPONDENCE.pdf

766-KOL-2008-(19-12-2011)-ABSTRACT.pdf

766-KOL-2008-(19-12-2011)-CLAIMS.pdf

766-KOL-2008-(19-12-2011)-CORRESPONDENCE.pdf

766-KOL-2008-(19-12-2011)-DESCRIPTION (COMPLETE).pdf

766-KOL-2008-(19-12-2011)-FORM-1.pdf

766-KOL-2008-(19-12-2011)-FORM-2.pdf

766-KOL-2008-ABSTRACT.pdf

766-KOL-2008-CLAIMS.pdf

766-KOL-2008-CORRESPONDENCE 1.1.pdf

766-KOL-2008-CORRESPONDENCE.pdf

766-KOL-2008-DESCRIPTION (COMPLETE).pdf

766-KOL-2008-FORM 1.pdf

766-KOL-2008-FORM 18 1.1.pdf

766-kol-2008-form 18.pdf

766-KOL-2008-FORM 2.pdf

766-KOL-2008-FORM 3.pdf

766-KOL-2008-GPA.pdf

766-KOL-2008-GRANTED-ABSTRACT.pdf

766-KOL-2008-GRANTED-CLAIMS.pdf

766-KOL-2008-GRANTED-DESCRIPTION (COMPLETE).pdf

766-KOL-2008-GRANTED-FORM 1.pdf

766-KOL-2008-GRANTED-FORM 2.pdf

766-KOL-2008-GRANTED-SPECIFICATION.pdf

766-KOL-2008-REPLY TO EXAMINATION REPORT 1.1.pdf

766-KOL-2008-REPLY TO EXAMINATION REPORT.pdf

766-KOL-2008-SPECIFICATION.pdf


Patent Number 254259
Indian Patent Application Number 766/KOL/2008
PG Journal Number 41/2012
Publication Date 12-Oct-2012
Grant Date 10-Oct-2012
Date of Filing 24-Apr-2008
Name of Patentee BHARAT HEAVY ELECTRICALS LIMITED
Applicant Address REGIONAL OPERATIONS DIVISION (ROD), PLOT NO : 9/1, DJ BLOCK 3RD FLOOR, KARUNAMOYEE, SALT LAKE CITY, KOLKATA - 700091, HAVING ITS REGISTERED OFFICE AT BHEL HOUSE, SIRI FORT, NEW DELHI – 110049, INDIA
Inventors:
# Inventor's Name Inventor's Address
1 TANGIRALA SITA RAMA MURTHY BHEL R&D, HYDERABAD
2 KANURU PRABHAKARA RAO BHEL R&D, HYDERABAD
3 MS MEENAKSHI BHEL R&D, HYDERABAD
PCT International Classification Number B01D
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA