Khalik M. Sabil

Study of 1-(2-hydroxyethyle) 3-methylimidazolium halide as thermodynamic inhibitors

In this study, the performance of 1-(2-Hydroxyethyle) 3-methylimidazolium chloride [OH-EMIM][Cl] and 1-(2-Hydroxyethyle) 3-methylimidazolium bromide [OH-EMIM][Br] was investigated as thermodynamic gas hydrate inhibitors. The dissociation temperature was determined for methane gas hydrates using a high pressure micro deferential scanning calorimeter at a pressure range of 36-97 bar. Both ionic liquids (ILs) were studied at concentrations of 5, 10, 15, 20 and 25 wt% then their performance was compared with commercially available inhibitors. It was observed that both ILs shift the methane hydrate equilibrium curve to lower temperature and higher pressure; and the performance of [OH-EMIM][Cl] is better than [OH-EMIM][Br]. Nevertheless both of them were found to be less effective compared to methanol and mono ethylene glycol.

Capturing Carbon Dioxide Through a Gas Hyydrate-based Process

a Research Center for CO2 Capturing, Chemical Engineering Department, Universiti Teknology PETRONAS, 32610 Bandar Seri Iskandar, Perak Darul Ridzuan, Malaysia b Institute of Petroleum Engineering, School of Energy, Geoscience, Infrastucture and Society, Heriot-Watt University, Malaysia, No 1 Jalan Venna P5/2, Precinct 5, 62200 Putrajaya, Federal Territory of Putrajaya Malaysia bezadpartoon@gmail.com

Characterization and Assessment of Cockle Shell as Potential CO2 Adsorbents

Material characterization is a crucial step to ensure the characteristics and properties of the samples are comparable to the standard adsorbent and suitable for CO2 adsorption. The objective of this work is to characterize natural calcium based materials for CO2 adsorption which are obtained from waste cockle shells. Characterization analyses are conducted by using XRD, BET and FESEM. Material characterization indicates that raw cockle shell is made up of aragonite and needle-like structure. It is also shown that CaCO3 can be decomposed to CaO through high temperature calcination process. Through physisorption analysis, the samples are classified as mesoporous materials and it is shown that calcined cockle shell is better than raw cockle shell in term of surface area and pore volume. The results proved that calcium based materials could be successfully employed as sorbent for CO2 separation.

Permeability Evaluation in Hydrate-Bearing Sand Using Tubular Cell Setup

Production of natural gas from hydrate-bearing sediments is significantly influenced by permeability variations in the presence of gas hydrate. The quantification on how absolute permeability and relative permeability affect natural gas production from hydrate-bearing sediments is one of the key interests for reservoir engineering studies. This study focuses on the relationship between water saturation, permeability, and porosity in unconsolidated quartz sand. Methane hydrate was formed in quartz sand in high-pressure stainless steel cell using deionized water at 276 K and 8 MPa. The sand pack with porosity of 40% was saturated with 35% water. This study found that porosity of the sample reduced significantly as the sand pack saturated with 35% of water. Porosity reduced from 40 to 37.4% due to the increase of hydrate saturation. Absolute permeability is 108.72 mD, and it was measured before gas hydrate formation. Relative permeability was measured after gas hydrate formation, and results show that relative permeability is 0.49. Formation of hydrate in pores significantly reduces the relative permeability and porosity. Relative permeability from this work is compared with a theoretical model, and the value shows that the relative permeability from this work is close to the value from Masuda model with N = 10.

Sorption equilibria of CO2 on synthesized CaO in the presence of water

Calcium-based adsorbents produced by biomass material is technically feasible, costly effective and advantageous to a certain extent in capturing CO2. Since the waste of a cockle shell is found to contain around 98% calcium, it can be a good source for CaCO3 and yield CaO through the high temperature calcination process. The sorption equilibria of CO2 on synthesized CaO with different amounts of water were measured experimentally by using a volumetric method at a temperature of 2°C. Under dry conditions, synthesized CaO has a low CO2 uptake, as the adsorption rate of CO2 in calcium-based sorbent is high at higher temperatures. While under wet conditions, the large increment of CO2 adsorption was observed due to formation of CO2 hydrates which were indicated by inflection of isotherms at a definite pressure of the S-shape. At the inflection point, the highest sorption capacity (5.07 mmol/g) was obtained at a water ratio of 0.55, which is about 30 times higher than dry samples. The trend of FTIR spectra were observed to be similar for raw cockle shells and wet CaO after CO2 adsorption, in contrast with spectra of CaO before adsorption. The formation of CO2 hydrate can be further verified by the changes of surface morphology of CaO, before and after adsorption. It can be concluded that calcium-based sorbent with the presence of water has the ability to be further utilized for CO2 separation.

The Impact of the Composition of the Crude Oils on the Wax Crystallization

One of the major problems in petroleum industry is wax precipitation and deposition. The component’s compositional and structural analysis of the crude oils is key factors to be studied to mitigate wax formation and precipitation tendency for the betterment of the crude oil flowability. In this work, the compositions and structures of two Malaysian and Sudanese crude oil samples were determined to investigate their effects on wax precipitation. The GC/MS was used to analyze hydrocarbon components. For this work, high pressure micro differential scanning calorimetry (HPμDSC) is used to determine the wax crystallization point and solubility curve. Results showed a linear relationship between wax appearance temperature (WAT) and weight percentage of component in the crude oil having > 14 carbon atoms. In addition, the effect of temperature on the amount of wax precipitation has also been investigated. Keywords: N-paraffin, Wax appearance temperature, Wax precipitation, High pressure micro differential scanning calorimetry

Impact of Gas Phase Composition on Gas Hydrate Process for Carbon Dioxide Capturing from Gaseous Mixtures

Hydrate based technology is a promising new process for separation of Carbon dioxide from different gas mixtures. The process is claimed to be less energy intensive, green and low technology. In this article effect of composition on the efficiency of such process is discussed. CSMGem software is used for analysis. Results shows that gas phase composition have important impact on the efficiency of process.

Effect of Porosity to Methane Hydrate Formation in Quartz Sand

Natural gas hydrates are recognized as the potential source of methane gas as the current estimates of the global methane hydrates inventory range between 1000 and 10000 Giga Tonnes of carbon. The behavior of methane hydrate formation in porous media is investigated in the Tubular Hydrate Cell at 8 MPa and 276 K. The present work is focused on finding the optimum porosity of the quartz sand with the grain sizes of 600–800 µm that could accelerate the methane hydrate formation. The effect of different porosity (O of 0.32, 0.34, 0.37, and 0.4) on the methane hydrate induction time, methane hydrate saturation, and the time taken for methane hydrates to completely form in the unconsolidated sand is investigated. The result shows that the optimum value for porosity is 32% based on the fastest time taken for complete formation and largest value of methane hydrate saturation which is 33.35 h and 6.34%, respectively, at the specified operating conditions.

Addition of water in calcium based adsorbent for CO2 adsorption: Experimental and isotherm modelling studies

In this work, a combined process of adsorption and gas hydrate formation is proposed as an alternative approach for the separation of carbon dioxide (CO2) content from gas stream. The objective of this research is to study adsorption isotherms of the CO2 gas onto the synthesized calcium oxide (CaO) via a static volumetric method at 2 °C at a different amount of water ratio (Rw). A large increment of CO2 adsorption was observed on the wetted sample due to formation of CO2 hydrates, particularly at high pressure. The highest adsorption capacity was obtained at Rw of 0.67. The experimental data of CO2 adsorption isotherms for Rw = 0 and Rw = 0.67 are further analyzed by five isotherm models which are Langmuir, Freundlich, Redlich-Peterson (R-P), Toth and Sips. The Freundlich model satisfactorily describes the CO2 adsorption onto the dried sample, whilst the R-P model is best fitted for the wetted sample.

CO2 rich gas mixture hydrate-liquid water- vapor (H-Lw-V) equilibrium measurement and prediction

In this paper we present experimental hydrate-liquid water vapor equilibrium data for mixtures of gas comprising rich CO2 content. Data were generated by a reliable step-heating technique validated using measured data for CH4. The experimental results obtained in this measurement were compared with various commercial softwares (CSMGem, CSMHYD). The prediction results obtained with different software packages shows in weak agreement with experiment data point with high average absolute error (AAE) of 1.18 and 1.45 for hydrate equilibrium pressure condition while with model used in this work the average absolute error obtained is 0.01 respectively.