PDF Extraction of Sulphur Species Using Deep Eutectic Solvent

A project thesis submitted to the Chemical Engineering program Universiti Teknologi PETRONAS as partial fulfillment of the requirement for Therefore, a lot of research has been done to reduce the sulfur content of the fuel to meet the regulatory requirement. The parameters of interest in the experiment are effect of initial concentration of model oil, volume ratio of model oil to DES and molar ratio of glycerol to choline chloride.

I am also very thankful to the Head of Center for Research in Ionic Liquid (CORIL), Assoc. Finally, to those who directly or indirectly contribute to the completion of my FYP. The sulfur composition in diesel fuels has higher molecular weight and larger ring sizes compared to gasoline due to differences in boiling point.

Concentration of the SO2 in the exhaust gas is closely related to the sulfur content in the fuel. The higher the concentration of sulfur species in the diesel fuel, the higher the concentration of SO2 emitted to the air.

Objectives

SO2 can be oxidized to form sulfur trioxide (SO3), a precursor to sulfuric acid, which can cause acid rain. Acid deposition resulting from acid rain adversely affects soil, trees, animals, water, human health and buildings.

Scope of Study

Finally, recycling and regeneration study of the deep eutectic solvents is carried out to minimize waste production in the process.

Relevancy of the Study

LITERATURE REVIEW

Ionic Liquid
Deep Eutectic Solvents
Application Deep Eutectic Solvent
Choline chloride-glycerol deep eutectic solvents
Liquid-liquid Extraction
Desulphurisation via liquid-liquid extraction
METHODOLOGY

Project Process Flow
Gantt Chart and Key Milestones
Deep Eutectic Solvents Synthesis
Deep Eutectic Solvents Characterisation
Model Oil Preparation
Deep Eutectic Solvent Performance

Zhang et al (2012) said the new type of ionic liquid is known as Deep Eutectic Solvents (DES). The first discovery of eutectic solvent by a mixture of urea and choline chloride with molar ratio 2:1 and melting points 133oC and 302oC respectively (Abo- Hamad et al., 2015). The two components of DES are environmentally friendly and abundant in nature, such as choline chloride.

In one research, DES have been tested as extracting solvents in liquid-liquid separation of azeotropic mixtures (Oliveira et al., 2013). Shakirullah et al., 2010) determined that liquid-liquid extraction is widely used in the purification of organic compounds, and the same is very useful in removing unwanted sulfur compounds from petroleum hydrocarbons. The solute is distributed between the food and the solvents so that the ratio of the concentration of solute in the food to the concentration of solute in the solvent remains constant at constant temperature.

If CA is the concentration in layer A and CB is the concentration in layer B, then at constant temperature:. As a very rough approximation, the partition coefficient can be measured equal to the ratio of the solubility in the two solvents. Organic sulfur compounds are mostly soluble in the polar solvents; besides, solvents having an affinity for the sulfur compounds may be more useful in their extraction.

There are seven milestones in the project which are submission of extended proposal, proposal defense, submission of final interim report, submission of progress report, submission of dissertation and technical paper, viva and finally submission of project dissertation in week 28 Please refer to Figure 3.2 in the appendices section for more details on Gantt charts and highlights. Deep eutectic solvents can be prepared by mixing choline chloride and glycerol in a molar ratio of and 1:4.

The amount of dibenzothiophene and benzothiophene required to prepare 100 ml of model oil containing different concentrations of sulfur species is shown in Table 3.3 and Table 3.4 respectively. Shimadzu GC-2010 gas chromatography (SGE BP1 capillary column, 30 m × 0.25 mm, 0.25 μm film thickness) with flame ionization detector was used to determine the concentration of DBT remaining in the dodecane layer before and after desulfurization. The volume of DES was determined to be 4 ml for each volume ratio. The mixture was stirred at 400 rpm.

The performance of DES can be monitored by calculating the desulfurization efficiency of DBT or BT sulfur species in the model oil. Gas chromatography was used to determine the concentration of DBT remaining in the n-dodecane layer before and after desulfurization.

Table 2.1 Melting Point of Deep Eutectic Solvents

RESULTS AND DISCUSSION

Characterisation DES
Effect of extraction time on BT extraction
Effect of extraction time on DBT extraction
Selectivity of Sulphur Species on Extraction
Effect of Model Oil Concentration on DBT and BT extraction
Effect of DES: Model Oil Volume Ratio on DBT extraction
Effect of Choline Chloride: Glycerol Ratio on DBT extraction
Recycling and regeneration

In the experiment, the fixed parameters are DES: molar ratio of choline chloride and glycerol is 1:2, volume ratio of DES: model oil is 1:5, extraction time 3 hours and at room temperature. After equilibrium between model oil and DES is reached, the extraction efficiency shows no significant change. 2012) also stated that the optimal extraction time for desulfurization efficiency is 30 minutes. The parameter set for the experiment was 300 ppm sulfur, the molar ratio of DES choline chloride and glycerol was 1:2, the volume ratio of DES:model oil was 1:5, extraction time 3 hours and at room temperature.

This is to determine the efficiency of the DES to extract sulfur from the model oil as the sulfur content in model oil increases. The constant parameter for this experiment is carried out at room temperature, the ratio DES molar ratio choline chloride: glycerol 1:2 and volume ratio DES: model oil 1:5. As the model oil concentration increases, the amount of sulfur extracted from model oil after DES increases, the empty space between the DES molecule becomes more concentrated and therefore the extraction efficiency decreases.

In this experiment, the fixed parameter is the concentration of DBT in model oil 300 ppm, the DES choline chloride:glycerol molar ratio was 1:2 and at room temperature. The amount of DES use is 4 ml. The sample for analysis is taken every 30 minutes for 3 hours. Based on Figure 4.5, the sulfur extraction efficiency decreased as the volume of the model oil increased.

Based on previous research conducted by Haoijie et al. 2014), sulfur extraction efficiency increases as the ratio of DES/model oil increases. Before the experiment, the DES volume was set at 4 ml for each experiment and the volume of the model oil varied. DBT had more contact possibilities with DES at a higher ratio of DES to model oil or at a lower volume of the model oil.

The parameter held constant for this study is the concentration of DBT in model oil. 300 ppm, volume ratio DES:model oil was 1:5, the mole ratio choline chloride:glycerol is 1:2 and at room temperature. The sample for analysis taken after 3 hours. The DES is reused after the first extraction and the second cycle performed using the same parameter.

Figure 4.1 Effect of extraction time on BT extraction efficiency [Room temperature, DES molar ratio choline chloride and glycerol is 1:2, stirring speed at 400rpm and volume ratio DES: model oil is 1:5]

CONCLUSION AND RECOMMENDATION

Conclusion
Recommendation
Overview Process Flow
Calculation amount of Dibenzothiophene needed to dissolve in dodecane Calculation shown based on 300 ppm sulphur in dodecane
Calculation amount of Benzothiophene needed to dissolve in dodecane Calculation shown based on 200 ppm sulphur in dodecane

Therefore, it is expected that the extraction does not require higher temperature and can be carried out at room temperature. Apart from that, the desulfurization with DES is still new and has rarely been reported in any literature. The desulfurization can be extended by performing photooxidative extraction using metal doped TiO as photocatalyst.

The photocatalyst can be suspended in the model oil containing DBT and photooxidation can be conducted under halogen lamp. However, TiO2 cannot fully utilize the solar energy since the ultraviolet radiation intensity is not very high in the solar energy that reaches the Earth. Then, using DES, DBTO2 can be extracted from the model oil via liquid-liquid extraction process.

In actual diesel, there are many other non-aromatic sulfur compounds, such as thiol sulfides, which DES night does not extract them effectively. In addition, the data experiment conducted using real oil is more realistic than model oil. Ionic liquids and eutectic mixtures as solvents and templates in zeolite analogue synthesis, Nature.

Extraction of S and N compounds from the mixture of hydrocarbons with ionic liquids as selective solvents. A new technique for separating glycerin from palm oil-based biodiesel using ionic liquids, Fuel Process. Liquid-liquid equilibria for the ternary system (phosphonium-based deep eutectic solvent-benzenehexane) at different temperatures: a new solvent introduced, Fluid Phase Equilib.

Liao, H.-G., Jiang, Y.-X., Zhou, Z.-Y., Chen, S.P., Sun, S.G., Shape-controlled synthesis of gold nanoparticles in deep eutectic solvents for structure studies–. functional relationships in electrocatalysis, Angew. Desulfurization of dibenzothiophene by chemical oxidation and solvent extraction with Me3NCH2C6H5Cl.2ZnCl2 ionic liquid. Oxidation of dibenzothiophene with laccase or hydrogen peroxide and deep desulfurization of diesel fuel with the latter.

Density and dynamic viscosities (choline chloride + glycerol) of the deep eutectic solvent and its aqueous mixtures in the temperature range K. Calculation of the amount of dibenzothiophene required for dissolution in dodecane Calculation shown based on 300 ppm sulfur in dodecane Calculation shown based on 300 ppm sulfur in dodecane.