Description:FIELD
The present disclosure relates to a process for removal of sodium from di-sulfide oil.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Disulfide oil (DSO), consisting of C2 to C4 di-sulfides, is produced during regeneration of spent caustic in Merox process for removal of mercaptans from liquefied petroleum gas (LPG: Scheme 1).
RSH + NaOH ? NaSR + H2O
4NaSR + O2 + 2H2O ? 2RSSR + 4NaOH
Scheme 1- Production of DSO
Generally, total sulfur content in DSO is in the range of 60 % to 65% depending upon its composition. Due to high sulfur content, DSO can be used as a pre-sulfiding agent in steam crackers and for pre-sulfiding of a hydro-treating catalyst. DSO produced from the Merox process contains sodium in the range of 1 ppm to 10 ppm. Sodium content higher than 0.5 ppm in DSO is not desirable for pre-sulfiding of the hydro-treating catalyst. Therefore, DSO is required to be treated with a suitable adsorbent to reduce the sodium content in DSO to less than 0.5 ppm.
Commercially, there are alumina based adsorbents available/ known for the treatment of DSO for reducing its sodium content. However, these adsorbents may be suitable for treatment of DSO having lower sodium concentration in the range of 1 ppm to 2 ppm and hence such known adsorbents are not very efficient for the removal of sodium from DSO containing higher sodium concentration.
There is, therefore, felt a need to provide a process for removal of sodium from di-sulfide oil that mitigates the drawbacks mentioned hereinabove or at least provide a useful alternative.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to ameliorate one or more problems of the background or to at least provide a useful alternative.
Another object of the present disclosure is to provide a process for removal of sodium from di-sulfide oil.
Still another object of the present disclosure is to provide a simple and economical process for removal of sodium from di-sulfide oil.
Another object of the present disclosure is to provide a process for removal of sodium from di-sulfide oil to obtain a treated di-sulfide oil having sodium content below 0.5 ppm.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to a process for removal of sodium content from di-sulfide oil. The process comprises passing a stream of di-sulfide oil having sodium level in the range of 5 ppm to 30 ppm through a zeolite bed packed in a column, at a liquid hourly space velocity (LHSV) ranging from 0.2 h-1 to 6 h-1 at a predetermined temperature and a predetermined pressure for a pre-determined period of time to obtain a treated di-sulfide oil having sodium content below 0.5 ppm.
In accordance with the present disclosure, the LHSV is in the range of 0.3 h-1 to 6 h-1. In another embodiment of the present disclosure, the LHSV is in the range of 0.3 h-1 to 5.2 h-1.
In accordance with the present disclosure, the pre-determined temperature is in the range of 20ºC to 40ºC. In another embodiment, the pre-determined temperature is in the range of 20ºC to 30ºC.
In accordance with the present disclosure, the pre-determined time period is in the range of 400 hrs. to more than 900 hrs.
In accordance with the present disclosure, the predetermined pressure is in the range of 1 atmosphere to 4 atmospheres.
In accordance with an embodiment of the present disclosure, the length of the adsorbent bed to diameter (L/D) ratio is in the range of 1.5 to 4.5.
In accordance with an embodiment of the present disclosure, the treated stream has sodium in the range of 0.05 ppm to 0.5 ppm. In another embodiment of the present disclosure, the treated stream comprises di-sulfide oil that has sodium in the range of 0.05 ppm to 0.3 ppm. In another embodiment of the present disclosure, the treated DSO stream has sodium in the range of 0.05 ppm to 0.2 ppm.
In accordance with the present disclosure, the zeolite is at least one selected from the group consisting of faujasite zeolite, zeolite X, zeolite Y, zeolite 3Å, zeolite Å, zeolite 5Å and ZSM-5.
In accordance with the present disclosure, the zeolite has silica to alumina ratio (SAR) in the range of 5 to 80.
In accordance with the present disclosure, the zeolite for removal of sodium content to less than 0.5 ppm is having a surface area in the range of 600 m2/g to 1000 m2/g, bulk density in the range of 300 kg/cm3 to 450 kg/m3, soda content in the range of 0.01wt% to 0.6wt%, crushing strength in the range of 1.5 kgf to 6 kgf; and attrition loss < 0.1%.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a removal of sodium from DSO with respect to time in a continuous flow reactor in the Example 3, in accordance with the present disclosure;
Figure 2 illustrates a removal of sodium from DSO with respect to time in a continuous flow reactor by using regenerated adsorbent (regeneration of spent adsorbent obtained from example 3), in accordance with the present disclosure;
Figure 3 illustrates a removal of sodium from DSO with respect to time in a continuous flow reactor, in accordance with the present disclosure;
Figure 4 illustrates a removal of sodium from DSO with respect to time in a continuous flow reactor in accordance with the present disclosure.
Figure 5 illustrates a removal of sodium from DSO by using commercial alumina and a cation exchanged zeolite Y.
Figure 6 illustrates a removal of sodium using a cation exchanged Zeolite-Y for a lab scale and commercially scaled up experiments.
DETAILED DESCRIPTION
The present disclosure relates to a process for removal of sodium from disulfide oil.
Embodiments of the present disclosure will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Disulfide oil (DSO), consisting of C2 to C4 di-sulfides, is produced during regeneration of spent caustic in Merox process for removal of mercaptans from liquefied petroleum gas (LPG: Scheme 1).
RSH + NaOH ? NaSR + H2O
4NaSR + O2 + 2H2O ? 2RSSR + 4NaOH
Scheme 1- Production of DSO
Generally, total sulfur content in DSO is in the range of 60 % to 65% depending upon its composition. Due to high sulfur content, DSO can be used as a pre-sulfiding agent in steam crackers and for pre-sulfiding of a hydro-treating catalyst. DSO produced from the Merox process contains sodium in the range of 1 ppm to 10 ppm. Sodium content higher than 0.5 ppm in DSO is not desirable for pre-sulfiding of the hydro-treating catalyst. Therefore, DSO is required to be treated with a suitable adsorbent to reduce the sodium content in DSO to less than 0.5 ppm.
Commercially, there are alumina based adsorbents available / known for the treatment of DSO. These adsorbent may treat DSO having lower sodium concentration in the range of 1 ppm to 2 ppm. However, these adsorbents are not very efficient for the removal of sodium from DSO containing higher sodium concentration in the range of 5 ppm to 30 ppm.
The present disclosure provides a process for removal of sodium from di-sulfide oil (DSO) for obtaining a treated di-sulfide oil.
The process of the present disclosure provides a treated di-sulfide oil having sodium content less than 0.5 ppm from a stream of di-sulfide oil having sodium content in the range of 5 ppm to 30 ppm.
The process for removal of sodium from di-sulfide oil (DSO) comprises passing a stream of di-sulfide oil having sodium content in the range of 5 ppm to 30 ppm through a zeolite bed packed column, at a liquid hourly space velocity (LHSV) ranging from 0.2 h-1 to 6 h-1 at a predetermined temperature and pressure for a predetermined period of time to obtain a treated di-sulfide oil having sodium content less than 0.5 ppm.
In accordance with an embodiment of the present disclosure, the LHSV is in the range of 0.3 h-1 to 6 h-1. In another embodiment of the present disclosure, the LHSV is in the range of 0.3 h-1 to 5.2 h-1. In an exemplary embodiment of the present disclosure, LHSV is 2.6 h-1.
In accordance with the present disclosure, the pre-determined temperature is in the range of 20ºC to 40ºC. In an embodiment of the present disclosure, the pre-determined temperature is in the range of 20ºC to 30ºC. In an exemplary embodiment, the pre-determined temperature is 25oC.
In accordance with an embodiment of the present disclosure, the predetermined pressure is in the range of 1 atmosphere to 4 atmospheres. In an exemplary embodiment, the pre-determined pressure is 1 atmosphere.
In accordance with an embodiment of the present disclosure, the predetermined period of time ranges from 400 hrs. to more than 900 hrs. In an exemplary embodiment, the predetermined time period is 400 hrs. In another exemplary embodiment, the pre-determined time period is 925 hrs.
In accordance with an embodiment of the present disclosure, the treated stream of di-sulfide is having sodium content in the range of 0.05 ppm to 0.5 ppm. In another embodiment of the present disclosure, the treated stream of disulfide oil has sodium content in the range of 0.05 ppm to 0.3 ppm. In yet another embodiment of the present disclosure, the treated DSO stream has sodium content in the range of 0.05 ppm to 0.2 ppm.
In accordance with an embodiment of the present disclosure, the zeolite is at least one selected from the group consisting of faujasite zeolite, zeolite X, zeolite Y, zeolite 3Å, zeolite Å, zeolite 5Å and ZSM-5.
In accordance with an embodiment of the present disclosure, the zeolite has silica to alumina ratio (SAR) in the range of 5 to 80.
In accordance with an embodiment of the present disclosure, a ratio of the length of the adsorbent bed to diameter of the adsorbent bed (L/D) ratio) is in the range of 1.5 to 5. In an exemplary embodiment, the length of the adsorbent bed to the diameter of the adsorbent bed (L/D ratio) is 2. In another exemplary embodiment, the length of the adsorbent bed to the diameter of the adsorbent bed L/D ratio is 4.5.
Selection of a suitable zeolite is critical for the removal of sodium in the treated DSO to less than 0.5 ppm. A zeolite is characterized by its surface area, bulk density, crushing strength and attrition loss.
In accordance with an embodiment of the present disclosure, the zeolite for removal of sodium to less than 0.5 ppm is characterized by the properties as disclosed hereunder:
Surface area is in the range of 600 m2/g to 1000 m2/g;
Bulk density ranging from 300 kg/cm3 to 450 kg/m3;
Crushing strength ranging from 1.5 kgf to 6 kgf; and
Attrition loss < 0.1 %.
Soda content in the range of 0.01wt% to 0.6 wt%.
In accordance with an embodiment of the present disclosure, zeolite is selected from a cylindrical zeolite and a spherical zeolite.
In accordance with an embodiment of the present disclosure, the cylindrical zeolite has a diameter in the range of 1 mm to 3 mm and a length in the range of 0.5 cm to 2 cm.
In accordance with the present disclosure, the moisture content in the treated DSO is reduced by 40% to 50%. The moisture content in DSO feed is in the range of 800 ppm to 1200 ppm which is reduced to 250 ppm to 500 ppm after treatment with zeolite adsorbent.
In accordance with an embodiment of the present disclosure, extrudates of zeolite Y (Na-Y) were prepared using Na-Y powder. The extrudates were dried and its cation exchange was carried out using ammonium nitrate for exchanging sodium cations of Na-Y zeolite by ammonium ions.
In accordance with an embodiment of the present disclosure, cation exchanged zeolite is used as an adsorbent bed for removal of sodium content from DSO.
In accordance with an embodiment of the present disclosure, spent absorbent bed is regenerated. In an embodiment of the present disclosure, regeneration of the spent zeolite is carried out by washing the spent absorbent with distilled water and carrying out cation exchange using ammonium nitrate.
The foregoing description of the embodiments has been provided for purposes of illustration and is not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXPERIMENTAL DETAILS
Example 1: Equilibrium studies for screening of zeolite (adsorbent)
Equilibrium experiments were carried out using zeolite (adsorbent) by taking 1 g of pre-heated zeolite at 120°C for 4 hours in a 30 ml bottle. 5 g of disulfide oil (DSO) containing 5 ppm sodium was added to the bottle containing zeolite. The cap of the bottle was closed and stirred manually for 2 minutes to 5 minutes. Then the sample bottle containing the zeolite (adsorbent) and DSO was kept at the room temperature for 14 hours. After 14 hours, DSO was separated from the zeolite (adsorbent) and was analyzed for sodium content by inductively coupled plasma mass spectrometry (ICP-MS) for sodium content. Further, the equilibrium studies for other adsorbents including commercial alumina was also carried out as shown in Table 1.
Table 1: Screening of adsorbents for removal of sodium from DSO in equilibrium experiments
Sr. No. Adsorbent Sodium in treated DSO, ppm
1 H-Y Zeolite (SAR = 12) 0.47
2 H-Y Zeolite (SAR = 5.1) 0.2
3 Na-X 1.2
4 H-ZSM-5 0.29
5 Spent FCC 1.1
6 Commercial alumina 0.8

From Table 1, it is evident that H-Y Zeolite and H-ZSM-5 adsorbents showed lower sodium in treated DSO obtained from equilibrium adsorption studies as compared to commercial alumina. Therefore, these adsorbents were selected for removal of sodium from DSO in a continuous flow reactor.
Example 2: Ion exchange study of the zeolite (adsorbent), in accordance with the present disclosure
Step 1: Extrusion of Zeolite Y (Na-Y) Powder
For extrusion of Na-Y powder (SiO2/Al2O3 molar ratio = 5.1 and 12), pre-heated Na-Y and pseudobhoemite or kaolin (10-40% by weight of Na-Y) as a binder were mixed in a mortar and pestle for 5 minutes to 10 minutes to make a homogeneous powder. 54 ml of water containing contains 4% to 10% of acetic acid was added slowly and stepwise to prepare a dough. Crystalline methyl cellulose (0.5-1%) was also used as an extrusion aid. The extrudates of Na-Y were prepared from dough. The extrudates of Na-Y were first dried at a room temperature for 4 hours, then at 105°C for 16 hours and calcined in air at 550 °C for 6-8 hours to obtain extrudates of Na-Y.
Step 2: Ion Exchange of Na-Y Extrudates
Cation exchange of Na-Y was carried out using 0.5 molar solution of ammonium nitrate for exchanging sodium cations of Na-Y zeolite by ammonium ions. For cation exchange, 50 g of Na-Y extrudates from step 1 were taken in a 500 ml round bottom flask. 250 ml, 0.1 to 1.5 molar solution of ammonium nitrate was added to the flask containing Na-Y extrudates. A refluxing condenser was fitted to the flask. Cation exchange was carried out at 90°C to 100°C for 4 hours to obtain a solution containing zeolite Y extrudates. The solution containing zeolite Y extrudates was cooled to the room temperature. Excess solution from the flask was drained off and a sample of liquid and zeolite Y from solids was collected for the analysis to measure the sodium content in the liquid and solids by ICP-MS. The cation exchange procedure was repeated for 4 to 10 times to exchange the maximum sodium cations by ammonium ions. At each cation exchange step, sodium content was measured by ICP-MS analysis. After final cation exchange, the extrudates of zeolite Y were dried at 120°C for 14 hours followed by calcination in air at 540°C for 6 hours. The sodium content in the cation exchanged zeolite was found in the range of 0.024% to 0.6%.
For cation exchange of Na-Y, ammonium ions, ammonium acetate, ammonium sulphate, and ammonium chloride salts were also used in the place of ammonium nitrate.
Example 3: Process for removal of sodium from di-sulfide oil, in accordance with the present disclosure
10 g extrudates of cation exchanged zeolite Y (silica to alumina ratio of zeolite was 12; 1.5 mm of the diameter and 0.5 to 1 cm of the length of extrudates) obtained as per example 2 were charged in a glass reactor of 2 cm diameter. The length of zeolite (adsorbent) bed to diameter (L/D) ratio was calculated as 4.5. Untreated DSO containing 5 ppm sodium was fed to the reactor at 26 mL/h flow rate (LHSV = 1.3 h-1). The treated DSO was collected at every 1 hour of interval for sodium analysis in treated DSO by ICP-MS. The sodium content in the treated DSO was observed in the range of 0.15 ppm to 0.5 ppm as illustrated in Figure 1. The run was stopped after 427 hours as sodium content in treated DSO was observed higher than 0.5 ppm.
In accordance with the present disclosure, figure 1 depicts that on increasing the run length, sodium content in treated DSO is also increased significantly after 325 hours run length which may be due to saturation on adsorbent bed of zeolite. The moisture content in the DSO feed is in the range of 800 ppm to 1000 ppm which is reduced to 250 ppm after treatment with zeolite adsorbent.
Example 4: Regeneration of spent adsorbent obtained from example 3
Regeneration of the spent adsorbent obtained from example 3 was carried out by first washing with distilled water followed by ion exchange as per the experimental procedure mentioned in example 2. Before ion exchange, the washed spent adsorbent was dried and calcined. The activity of the regenerated adsorbent was evaluated for removal of sodium from DSO using the experimental conditions mentioned in Example 3. Sodium content in treated DSO was obtained in the range of 0.1 to 0.24 ppm upto 300 hours without any significant changes in the activity of regenerated adsorbent as shown in Figure 2.
In accordance with the present disclosure, figure 2 shows that the sodium content in the treated DSO is obtained in the range of 0.1 ppm to 0.24 ppm upto 300 hours run length without any significant changes in the activity of the regenerated adsorbent as compared to the fresh adsorbent.
Example 5: Process for removal of sodium from di-sulfide oil, in accordance with the present disclosure
10 g extrudates of cation exchanged zeolite Y (silica to alumina ratio of zeolite was 5.1; 1.5 mm of the diameter and 0.5 to 1 cm of the length of extrudates) obtained as per example 2 were charged in a glass reactor of 2 cm diameter. Untreated DSO containing 5 ppm sodium was fed to the reactor at 26 mL/h flow rate (LHSV = 1.3 h-1. The treated DSO was collected at every 1 hour of interval for sodium analysis in treated DSO by ICP-MS. Sodium content in the treated DSO was observed in the range of 0.1 ppm to 0.2 ppm as shown in Figure 3. The moisture in DSO feed was measured in the range of 800 ppm to 1200 ppm which was reduced to 250 ppm to 500 ppm after treatment with zeolite adsorbent.
In accordance with the present disclosure, figure 3 shows that sodium content in the treated DSO is in the range of 0.1 ppm to 0.2 ppm. The moisture in DSO feed is in the range of 800 ppm to 1200 ppm which is reduced to 250 ppm to 500 ppm after treatment with the zeolite adsorbent.
Experiments at varied LHSV of 0.31 h-1, 0.6 h-1, 1 h-1, 1.3 h-1, 2.6 h-1 and 5.2 h-1 were also carried out to study the effect of LHSV on sodium removal efficiency of adsorbent using feed DSO containing 5 ppm sodium. It was observed that, on increasing the LHSV from 0.31 to 5.2 h-1, sodium content in treated DSO was also increased from 0.1 ppm to 0.5 ppm as indicated in Table 2. Lower LHSV allow more contact time between feed DSO and adsorbent which results into lower sodium content in the treated DSO. The length of adsorbent bed to diameter (L/D) ratio was also varied from 2 to 4.5 in the experiments for sodium removal from DSO.
Table 2. Effect of LHSV on sodium removal efficiency of adsorbent
Sr. No. LHSV, h-1 Average sodium in treated DSO, ppm
1 0.31 0.1
2 0.6 0.15
3 1 0.14
4 1.3 0.15
5 2.6 0.25
6 5.2 0.5

Example 6: Effect of variation of sodium concentration in DSO feed
To study the effect of sodium concentration in DSO, 10 g extrudates of cation exchanged zeolite Y (1.5 mm diameter and 0.5 to 1 cm length of extrudates) obtained in example 2 were charged in a glass reactor of 2 cm diameter. The content of sodium in feed DSO was varied as 5 ppm, 15 ppm and 30 ppm and the DSO feed passed through the zeolite (adsorbent) bed at the flow rate of 26 mL/h (LHSV = 1.3 h-1). The treated DSO was collected at every 1 hour of interval for sodium analysis by ICP-MS. Sodium content in the treated DSO is shown in Table 3. Sodium content in the treated DSO increased on increase in the sodium concentration in feed DSO.
Table 3. Effect of sodium concentration in feed on activity of cation exchanged zeolite Y
Sr. No. Sodium content in untreated DSO (ppm) Sodium in treated DSO (ppm)
1 5 0.15
2 15 0.42
3 30 1.47

Example 7: Process for removal of sodium from di-sulfide oil, in accordance with the present disclosure
19.2 g extrudates of cation exchanged zeolite Y (1.5 mm diameter and 0.5 to 1 cm length of extrudates) obtained in example 2 were charged in a glass reactor of 2.94 cm diameter. The length of adsorbent bed to diameter (L/D) ratio was calculated as 2. DSO containing 5 ppm sodium was fed to the reactor at 12 mL/h flow rate (LHSV = 0.31 h-1). Treated DSO was collected at every one-hour interval for sodium analysis in the treated DSO by ICP-MS. Initially less than 0.1 ppm sodium was observed in the treated DSO, that increased to the range of 0.1-0.2 ppm upto 500 h time on stream run as illustrated in Figure 4. A maximum of 0.3 ppm sodium in the treated DSO was observed in 900 h run. On increasing the run length (hours on stream), some of active sites for adsorption of sodium may be occupied thus reducing the activity of the adsorbent.
In accordance with the present disclosure, figure 4 showed that initially less than 0.1 ppm sodium was observed in treated DSO stream that increased to a range of 0.1-0.2 ppm upto 500 hours run length. Maximum 0.3 ppm sodium in treated DSO was observed after 900 hours run length. On increasing the run length, some of the active sites for adsorption of sodium may be occupied thus reducing the activity of the adsorbent. The moisture in DSO feed was measured in the range of 800-1200 ppm which reduced to the range of 250 ppm to 500 ppm after treatment with adsorbent.
Example 8: Comparative study for removal of sodium from di-sulfide oil using commercial alumina and cation exchanged zeolite Y adsorbents
For comparison of the data, removal of sodium was also carried out using commercial alumina as a reference adsorbent under similar experimental conditions as given in example 7. The sodium in the treated DSO was obtained in the range of 0.2 to 1.76 ppm using commercial alumina as an adsorbent, 5 ppm sodium in feed DSO, LHSV = 0.31 h-1. Comparative data for sodium in the treated DSO using commercial alumina and cation exchanged zeolite Y is shown in Figure 5. Alumina based adsorbent showed higher sodium content in the treated DSO than cation exchanged zeolite Y under the similar adsorption conditions. Sodium in the treated DSO was observed to increase from 0.2 to 1.76 ppm on increasing the run time to 775 h using alumina based adsorbent, whereas, the cation exchanged zeolite Y showed 0.1 to 0.33 ppm sodium in treated DSO. This data confirmed the higher sodium removal capacity of cation exchanged zeolite Y, disclosed in the present invention for removal of sodium from DSO.
Comparative data for sodium content in the treated DSO using commercial alumina and cation exchanged zeolite Y is shown in Figure 5. Alumina based adsorbent showed higher sodium content in treated DSO than cation exchanged zeolite Y under the similar adsorption conditions. Sodium content in the treated DSO was observed to increase from 0.2 to 1.76 ppm on increasing the run length to 775 h using alumina based adsorbent, whereas, cation exchanged zeolite Y as per the present disclosure, showed 0.1 to 0.33 ppm sodium in treated DSO. This data confirmed the higher sodium removal capacity of cation exchanged zeolite Y, disclosed in the present invention for removal of sodium from DSO.
Example 9: Scale-up of cation exchanged Zeolite-Y adsorbent
Scale-up of cation exchanged Zeolite-Y of SiO2/Al2O3molar ratio of 5.1 was carried out from 50 g batch to 200 kg level. The activity of composite cation exchanged Zeolite-Y adsorbent was evaluated for removal of sodium from DSO containing 5 ppm sodium and other reaction conditions similar to Example 7 and is shown in figure 6.
In accordance with the present disclosure, figure 6 shows the activity of scaled-up batch which was observed to be similar to the cation exchanged Zeolite-Y adsorbent prepared in lab at 50 g scale, confirming successful scale-up of the preparation of cation exchanged Zeolite-Y adsorbent. Sodium in the treated DSO was observed in the range of 0.1 ppm to 0.3 ppm using both adsorbent samples upto 870 h run length.
The activity of scaled-up batch was observed similar to cation exchanged Zeolite-Y adsorbent prepared in lab at 50 g scale (Figure 6) which confirmed successful scale-up of the preparation of cation exchanged Zeolite-Y adsorbent at bigger scale (200 kg).
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a process for removal of sodium from di-sulfide oil for obtaining a treated di-sulfide oil that:
is simple and economical;
is environment-friendly;
reduces sodium level below 0.5 ppm; and
the so obtained DSO has the potential to replace imported dimethyl disulphide (DMDS) for a steam cracker and a hydrotreater application.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising, will be understood to imply the inclusion of a stated element, integer or step,” or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. , Claims:WE CLAIM:
1. A process for removal of sodium from di-sulfide oil for obtaining a treated di-sulfide oil having sodium content below 0.5 ppm, said process comprising passing a stream of di-sulfide oil having sodium content in the range of 5 ppm to 30 ppm through a zeolite bed packed in a column, at a liquid hourly space velocity (LHSV) ranging from 0.2 h-1 to 6 h-1 at a predetermined temperature for a predetermined time period and at a predetermined pressure to obtain said treated di-sulfide oil having sodium content below 0.5 ppm.
2. The process as claimed in claim 1, wherein said liquid hourly space velocity (LHSV) is in the range of 0.3 h-1 to 6 h-1.
3. The process as claimed in claim 1, wherein said liquid hourly space velocity (LHSV) is in the range of 0.3 h-1 to 5.2 h-1.
4. The process as claimed in claim 1, wherein said pre-determined temperature is in the range of 20ºC to 40ºC.
5. The process as claimed in claim 1, wherein said pre-determined temperature is in the range of 20ºC to 30ºC.
6. The process as claimed in claim 1, wherein said pre-determined time period is in the range of 400 hrs to more than 900 hrs.
7. The process as claimed in claim 1, wherein said predetermined pressure is in the range of 1 atmosphere to 4 atmospheres.
8. The process as claimed in claim 1, wherein said treated stream comprising di-sulfide oil is having sodium in the range of 0.05 ppm to 0.5 ppm.
9. The process as claimed in claim 1, wherein said treated stream comprising di-sulfide oil is having sodium in the range of 0.05 ppm to 0.3 ppm.
10. The process as claimed in claim 1, wherein said treated stream comprising di-sulfide oil is having sodium in the range of 0.05 ppm to 0.2 ppm.
11. The process as claimed in claim 1, wherein said zeolite has silica to alumina ratio (SAR) in the range of 5 to 80.
12. The process as claimed in claim 1, wherein said zeolite is at least one selected from the group consisting of faujasite zeolite, extrudate of zeolite, zeolite X, zeolite Y, zeolite 3Å, zeoliteÅ, zeolite 5Å and ZSM-5.
13. The process as claimed in claim 1, wherein said zeolite has a surface area in the range of 600 m2/g to 1000 m2/g.
14. The process as claimed in claim 1, wherein said zeolite has a soda content in the range of 0.01wt% to 0.6 wt.%.
15. The process as claimed in claim 1, wherein said zeolite has a crushing strength in the range of 1.5 kgf to 6 kgf.
16. The process as claimed in claim 1, wherein said zeolite has a bulk density in the range of 300 kg/m3 to 450 kg/m3.
17. The process as claimed in claim 1, wherein said zeolite has attrition loss of <0.1%.
18. The process as claimed in claim 1, wherein said zeolite packed bed is cylindrical in shape having length to diameter ratio in the range of 1.5 to 4.5.
Dated this 28th day of December, 2023

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI