Santi Kulprathipanja

Mixed Matrix Membrane Development

Abstract: Two types of mixed matrix membranes were developed by UOP in the late 1980s. The first type includes adsorbent polymers, such as silicalite‐cellulose acetate (CA), NaX‐CA, and AgX‐CA mixed matrix membranes. The silicalite‐CA has a CO2/H2 selectivity of 5.15 ± 2.2. In contrast, the CA membrane has a CO2/H2 selectivity of 0.77 ± 0.06. The second type of mixed matrix membrane is PEG‐silicone rubber. The PEG‐silicone rubber mixed matrix membrane has high selectivity for polar gases, such as SO2, NH3, and H2S.

Mixed matrix membrane development

Abstract This article looks at two types of mixed matrix membranes that have been developed by UOP LLC. The first type includes adsorbent—polymers such as silicalite—cellulose acetate (CA), NaXCA and AgXCA mixed matrix membrane. The silicalite—CA has a CO 2 /H 2 selectivity of 5.15±2.20. In contrast, the cellulose acetate membrane has a CO 2 /H 2 selectivity of 0.77±0.06. The second type of mixed matrix membrane has a polyethyleneglycol silicone rubber structure. This has a high selectivity for polar gases such as SO 2 , NH 3 and H 2 S.

Effect of metal type and loading on hydrogen storage on NaAlH4

Although hydrogen has a great potential as clean energy, safe practical storage of hydrogen for applications such as fuel cells has been a major challenge. NaAlH4 is one of the metal hydrides, which are candidates for hydrogen storage in vehicles. However, the rather slow absorption/desorption kinetics is still a significant drawback. To alleviate this problem, purified NaAlH4 was ground with TiCl3, ZrCl4, or HfCl4. Desorption kinetics and capacities were observed under TPD-like operation. Absorption efficiency was determined by raising the temperature up to 125 8C. Of the three doped metals investigated for the positive effect on facilitating NaAlH4 decomposition, TiCl3 assists the best on the first reaction while ZrCl4 and HfCl4 do for the second one. Despite the kinetics enhancement directly involves with the ZrCl4 amount, there is a threshold of ZrCl4-content which affects. 6% ZrCl4 is considered as an appropriate amount to improve the hydrogen release because it simultaneously decreases the desorption temperature and gives the outstanding rate. In hydrogen desorption, ZrCl4 provides the most amount of released hydrogen, but for hydrogen absorption TiCl3-doped NaAlH4 possesses the highest capacity. It is believed that the metal size is one of the key factors resulting in such the behavior.

Phenol Hydroxylation with TS-1 in a Chromatographic Reactor

ABSTRACT Phenol hydroxylation with TS-1 was studied in a chromatographic reactor. TS-1 not only acts as the catalyst for the reaction but also the adsorbent for the separation. The reaction/separation was carried out at 60°C with water and 0.2wt% of aqueous H2O2 as the desorbent. Separation of hydroquinone (HQ) can be achieved in all cases. With water as the desorbent, separation of catechol (CT) depends on the phenol feed concentration, which has been confirmed from both reaction/separation in the chromatographic reactor and equilibrium competitive adsorption experiment. Some unknown by-products not commonly reported in batch experiments have been observed here. TS-1 can also be regenerated using just water. With the aqueous mixture of H2O2 as the desorbent, separation of HQ and CT is possible. Reactive separation schemes based on the simulated counter-current technology have been proposed according to the experimental results.

Phenol hydroxylation using Ti- and Sn-containing silicalitesElectronic supplementary information (ESI) available: XRD pattern of Ti?Sn?S-1s. See http://www.rsc.org/suppdata/cc/b3/b303455k/

New bimetallic framework and non-framework titanium and tin silicalite have been investigated for phenol hydroxylation with H2O2 in different solvents, and the optimized catalyst composition showed 26% higher initial rate than reference TS-1.

Roles of Sodium Dodecyl Sulfate on Tetrahydrofuran-Assisted Methane Hydrate Formation

Sodium dodecyl sulfate (SDS) markedly improved tetrahydrofuran (THF) - assisted methane hydrate formation. Firstly, methane hydrate formation with different THF amount, 1, 3, and 5.56 mol%, was studied. SDS with 1, 4, and 8 mM was then investigated for its roles on the methane hydrate formation with and without THF. The experiments were conducted in a quiescent condition in a fixed volume crystallizer at 8 MPa and 4°C. The results showed that almost all studied THF and SDS concentrations enhanced the methane hydrate formation kinetics and methane consumption compared to that without the promoters, except 1 mol% THF. Although, with 1 mol% THF, there were no hydrates formed for 48 hours, the addition of just 1 mM SDS surprisingly promoted the hydrate formation with a significant increased in the kinetics. This prompts the use of methane hydrate technology for natural gas storage application with minimal promoters.

Novel polymeric membrane materials for ethanol/water separation via pervaporation

In this research, novel polybenzoxazine (PBZ) membranes, synthesized from bisphenol-A, formaldehyde and diamines, were coated on a tubular alumina support by dip-coating technique for ethanol purification application via pervaporation. The effects of dipping time and precursor concentration on the membrane preparation and the separation performance showed that both PBZ membranes were remarkably stable, resistant to swelling, and provided an impressively high separation factor of higher than 10,000 for all ethanol concentration ranges, characteristics implying that they could be a good candidate for high purity ethanol production.

Effects of Metal Loading and Milling Time on Hydrogen Storage on Modified Graphite

This paper examines the effect of metal loading (Zr-, V-, Ti-, and K-compounds) on the hydrogen storage property of mechanically milled graphite. The hydrogen adsorption took place at room temperature and 11 MPa measured by thermal volumetric analysis. The results showed that the graphite loaded with ZrCl4 provided a maximum hydrogen storage capacity of 0.6 wt%. Moreover, a milling time of 2 h seems to be the best, offering the highest hydrogen adsorption capacity due to the high specific surface area and the appropriate pore diameter created after the milling. In addition, it was found that the transition metals (ZrCl4 and VCl3) could stabilize the graphite structure and enlarge the gap between the grapheme layers to be suitable trapping sites for hydrogen adsorption. On the other hand, the K2CO3 and TiO2 loaded graphite did not show any improvement for hydrogen adsorption.

SMB: Mono-methyl paraffin separation

Abstract A process for the recovery and purification of mono-methyl branched C 10 –C 15 paraffins from kerosene or n-paraffin depleted kerosene through an adsorptive separation has been developed. Two complimentary adsorptive separation-operating modes were demonstrated for efficient mono-methyl paraffin production. The first method uses simulated moving-bed adsorptive separation with a silicalite adsorbent and a mixture of C 5 and/or C 6 n-paraffin and iso and/or cyclo-paraffin as the desorbent. The second method, which provides enhanced mono-methyl paraffin recovery, uses the pre-pulse technique in combination with the first operating method. Pulse tests (chromatographic separation) with both techniques showed good performance in the laboratory. Both methods were demonstrated successfully in a continuous counter-current chromatographic separation pilot plant using commercial n-paraffin depleted kerosene feedstock. Better than 90% normal and mono-methyl paraffin purity with greater than 70% recovery of normal and mono-methyl paraffins was achieved from the pilot plant. Detailed information on the process development including feed composition, desorbent composition, temperature, diffusion rates, and model simulations will be discussed.