Microstructural wettability of oil and gas condensate zones of the Karachaganak field

The Karachaganak field is represented by gas condensate and oil zones, a convenient object for studying changes in microstructural wettability during the transition from one zone to another. Microstructural wettability was characterized by a hydrophobization coefficient, Ѳн, which determines the proportion of the pore surface area occupied by adsorbed hydrocarbons. It was found that Ѳн of the samples of the gas and gas condensate zones is the same (on average 0.140), the oil zone - on average 0.250. Analysis of the IR spectra of extracted hydrocarbons showed that the microstructural wettability of the oil zone contains more aromatic, aliphatic, oxidized and sulfur-containing structures and fewer branched structures than in the gas condensate zone. The microstructural wettability of carbonate reservoirs depends on the hydrocarbon composition of the adsorbed oil. Keywords: microstructural wettability; hydrophobic coefficient; hydrocarbons; spectral coefficients.

Immobilization of β-Glucosidase on Different Supports and Evaluation of Its Activity in Cellobiose Hydrolysis

β-glucosidase was used as catalyst for the hydrolysis of cellobiose, immobilized on different supports, including two silicas (MSNS and MCM-41) and three carbon supports (GAC, BDH and Norit). It was observed that mesoporous nanoparticles are better candidates as supports for the β-glucosidase, and that silica has a better performance, probably due to the presence of silanol groups. The MSNS showed better recovered activity compared to other supports, showing an optimum temperature at 70 0 C and an optimum pH of 5. The enzyme immobilized in MSNS showed results 80% to 98% better than those immobilized on other supports. However, for the recycling test, from the second cycle onwards, the MSNS showed a performance drop of around 40%, reaching a relative activity of 41.9% for both the fourth and the final cycle. MCM-41, on the other hand, did not show as much discrepancy in the recycling test. However, its relative activity in the first cycle was 20% of the activity achieved by MSNS, at its optimum temperature of 60 0 C. Such results indicate that the smaller particle size favours enzymatic activity. Notwithstanding, a larger available intra-pore surface area protects the enzyme from denaturation.

TEKNOLOGI PEMBUATAN ADSORBEN DARI LIMBAH EKSTRAKSI BIOSILIKA SEKAM PADI

Adsorbent from lignocellulosic waste constitutes an alternative in industry due to the large amount and easy to get. The unique characteristics of activated carbon from lignocellulosic waste as well as more economically with regard to mass production were the reasons for the development of by-products of this rice husk biosilica waste. This research aimed to produce adsorbent from waste of nanobiosilica powder extraction. Calcination or treatment without impregnation) and with impregnation were applied in this study. Calcination was carried out by heating the residual waste at 600 ° C; 700 ° C; and 800 ° C; however the impregnation process was carried out by immersing the residual waste with catalysts ZnCl2, H3PO4, and KOH with ratio 1: 1 and 1: 2 for 24 hours. Subsequently, carbonisation was carried out at 600 ° C; 700 ° C; and 800 ° C for 1 and 3 hours with variations in mesh sizes of 10, 20, 80, and 100 mesh. The results showed that the waste of nanobiosilica extraction still contained high SiO2 (89.86%) so that it could be used as raw material for adsorber to apply in water purification applications. The calcination treatment showed the highest absorption as well as the area of the pore surface. The best particle size was 100 mesh and calcined at 800 ° C in which has a pore surface area meet the requirement of commercial activated charcoal, which is 15.83 m² / g.

Diverse crystal size effects in covalent organic frameworks

Crystal size effect is of vital importance in materials science by exerting significant influence on various properties of materials and furthermore their functions. Crystal size effect of covalent organic frameworks (COFs) has never been reported because their controllable synthesis is difficult, despite their promising properties have been exhibited in many aspects. Here, we report the diverse crystal size effects of two representative COFs based on the successful realization of crystal-size-controlled synthesis. For LZU-111 with rigid spiral channels, size effect reflects in pore surface area by influencing the pore integrity, while for flexible COF-300 with straight channels, crystal size controls structural flexibility by altering the number of repeating units, which eventually changes sorption selectivity. With the understanding and insight of the structure-property correlation not only at microscale but also at mesoscale for COFs, this research will push the COF field step forward to a significant advancement in practical applications.

Activated Carbon Production Through Co-Pyrolysis of Vacuum Residue and Dehydrated Castor Oil

Crude oil refineries in Indonesia produce waste in the vacuum distillation as vacuum residue and utilization is still low. Vacuum residue contains high aromatics which can be utilized as raw material to produce activated carbon. Such a activated carbon is widely used as electric double-layer capacitors. Vacuum residue was mixed with dehydrated castor oil as conjugated double bond source, then followed by pyrolysis at heating rate of 5°C/min until 450°C and holding time at 450°C for 90 minutes. The amount of dehydrated castor oil added to vacuum residue was varied at 0 wt%, 5wt%, 10 wt%, and 15 wt% of vacuum residue. Co-pyrolysis of vacuum residue and dehydrated castor oil reduce C/H atomic ratio precursors, from 1.82 to 1.50, 1.48, and 1.45 and used as a precursor of activated carbon. The activation was conducted by activating the precursor with KOH solution and followed by carbonization at heating rate of 5°C/min until 700°C and holding time at 700°C for 30 minutes. The results show that the addition of castor oil improved pore surface area from 150.32 m2/g to 236.97, 290.99, and 357.78 m2/g, respectively, and also have high crystallinity structures, so they may be used as active materials in capacitors.

Methane Adsorption Interpreting with Adsorption Potential and Its Controlling Factors in Various Rank Coals

Water content, metamorphism (coal rank) particle size, and especially pore structure, strongly influence the adsorption capacity of coal to methane. To understand the mechanism of methane adsorption in different rank coals, and its controlling factors, isothermal adsorption experiments with different coal ranks, moisture contents and particle sizes at the temperature of 303.15 K were conducted. In addition, the pore structures of coals were investigated through N2 adsorption/desorption experiments at the low-temperature of 77 K for selected coals from the Junggar Basin of NW China, Qinshui Basin and Ordos Basin of north China. Moreover, the adsorption potential of methane on the surface of the coal matrix was calculated, the controlling factors of which were discussed. The obtained methane isothermal adsorption result shows that the Langmuir volume (VL) of coal is independent of the particle size, and decreases with the increase of moisture content, which decreases first and then increases when the coal rank increases. Combined with the pore structure by the N2 adsorption at 77 K, VL increases with the increase of pore surface area and pore volume of coal pores. Besides, the adsorption potential of all selected coals decreased with the increase of the methane adsorption volume, showing a negative relationship. The interesting phenomena was found that the surface adsorption potential of the coal matrix decreases with the increase of moisture content, and increases with the decrease of particle size at the same pressure. With the same adsorption amount, the adsorption potential on the surface of coal matrix decreases first, and then increases with the increase of coal rank, reaching a minimum at Ro,m of 1.38%, and enlarging with the increase of pore surface area and the pore volume of coal pores. These findings may have significant implications for discovering CBM accumulation areas and enhancing CBM recovery.

Conservation tillage positively influences soil organic carbon through earthworm excrement physical structure stability in a Chinese Mollisoil

<p>Identifying the relationship between earthworm activity and soil organic carbon is vital for both planning and performing farming operations. Numerous studies have emphasized that earthworms affect soil organic carbon greatly. However, the extent of this effect is still somewhat vague, and very little is known, not to mention the role of earthworm excrement. The objective for this study is to determine the effect of earthworm excrement on soil organic carbon following different tillage practices based on physical structure stability parameters. Both no tillage (NT) and ridge tillage (RT) led to significant total pore surface area, permeability, fluid conductivity, water resistance index and tensile strength increment than moldboard plow (MP) (p<0.05), whereas water repellency significant decrement (p<0.05). Similar to soil organic carbon, NT and RT significantly increase organic carbon in earthworm excrement than MP (p<0.05). A significant positive correlation (p<0.05) was found between organic carbon in earthworm excrement and total pore surface area, water repellency, tensile strength, respectively. This finding demonstrates that conservation tillage increase organic carbon in earthworm excrement through physical structure stability namely aggregation effect of earthworm excrement on soil water movement and gas diffusion, potentially important for the soil organic carbon increment.</p>

The Effect of Chitosan’s Addition to Resorcinol/Formaldehyde Xerogels on the Characteristics of Resultant Activated Carbon

Hybrid chitosan-resorcinol/formaldehyde xerogels were synthesized, and the effect of including minor quantities of chitosan on the consequent activated carbon was investigated. The resulting activated carbon were characterized by different techniques. Clear changes were found in the structure of activated carbon as a result of including chitosan in the synthesis. The results showed that the disorder ratio of crystal lattice decreased from 0.750 to 0.628 when increasing the concentration of chitosan from 0 to 0.037 wt%. The micropores increased from ~0.3% to ~1.0%, mesopores increased from ~11.2% to ~32.9% and macropores decreased from ~88.4% to ~66.1%. The total pore volume decreased from 1.040 to 0.238 cm3/g and the total pore surface area decreased from 912.3 to 554.4 m2/g. On the other hand, the average pore width decreased from 2.3 to 0.8 nm and the average particle size decreased from 224 to 149 nm. Nano-scale Scanning Electron Microscope (NanoSEM) morphology indicated a critical composition of chitosan (0.022 wt%) that affects the structure and thermal stability of activated carbon produced.

Nano-Scale Pore Structure and Fractal Dimension of Longmaxi Shale in the Upper Yangtze Region, South China: A Case Study of the Laifeng–Xianfeng Block Using HIM and N2 Adsorption

This paper tries to determine the key evaluation parameters of shale reservoirs in the complex tectonic provinces outside the Sichuan Basin in South China, and also to target the sweet spots of shale reservoirs accurately. The pore-structure characteristics of the Lower Silurian Longmaxi shale gas reservoirs in Well LD1 of the Laifeng–Xianfeng Block, Upper Yangtze region, were evaluated. N2 adsorption and helium ion microscope (HIM) were used to investigate the pore features including pore volume, pore surface area, and pore size distribution. The calculated results show good hydrocarbon storage capacity and development potential of the shale samples. Meanwhile, the reservoir space and migration pathways may be affected by the small pore size. As the main carrier of pores in shale, organic matter contributes significantly to the pore volume and surface area. Samples with higher total organic carbon (TOC) content generally have higher porosity. Based on the Frenkel–Halsey–Hill equation (FHH model), two different fractal dimensions, D1 and D2, were observed through the N2 adsorption experiment. By analyzing the data, we found that large pores usually have large values of fractal dimension, owing to their complex pore structure and rough surface. In addition, there exists a good positive correlation between fractal dimension and pore volume as well as pore surface area. The fractal dimension can be taken as a visual indicator that represents the degree of development of the pore structure in shale.

Influence of Open-Porous System on the Solid-State Phase Transition in 1-Octadecene

The solid-state phase transition in the silica gel–1-octadecene system has been studied at various temperatures with the help of differential scanning calorimetry and FTIR spectroscopy. Silica gels KSK-2.5, KSS-4, and Silica Gel 60 with different surface parameters are used. The temperature of the solid-state phase transition in the silica gel–1-octadecene system is shown to linearly depend on the ratio between the pore surface area and the pore volume. The energy characteristics of 1-octadecene nanocrystals in the surface layer are calculated in the framework of a thermodynamical model of crystal melting in pores.