Catalytic steam gasification of biomass for a sustainable hydrogen future: influence of catalyst composition

Hydrogen is regarded as a clean energy for fuelling the future. Hydrogen will be the energy carrier from other resources such as hydropower, wind, solar and biomass. Producing hydrogen from gasification of biomass wastes, particularly in the presence of steam, represents a promising route to produce this clean and CO2-neutral fuel. The steam pyrolysis-gasification ofbiomass (wood sawdust) was carried out with various nickel-based catalysts for hydrogen production in a two-stage fixed bed reaction system. The wood sawdust was pyrolysed in the first reactor and the derived products were gasified in the second reactor in the presence of the catalyst and steam. The synthesised Ni-Ca-Al and Ni-Zn-Al catalysts were preparedbyco-precipitation method with different Ni loadings of 20 mol% and various Zn/Al or Ca/Al ratios, which were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and temperature-programmed oxidation (TPO). The results showed that the Ni/Zn-Al (1:9) catalyst resulted in higher hydrogenproduction(23.9 mmol H2 g-1biomass)compared with the Ni/Ca-Al (1:9) catalyst (12.7 23.9 mmol H2 g-1 biomass) and in addition, the increase of Ca or Zn content in the catalyst slightly increased the hydrogen production. The TPO results showed that the catalyst suffered negligible coke deposition from the catalytic steam pyrolysis/gasification of wood sawdust. Additionally, Na2CO3 basic solution was also found toproduce a catalyst with better performance and lower coke deposition, compared with NH4OH catalyst preparation agent, as observed by TPO, SEM and TEM analysis

Advances in reforming and partial oxidation of hydrocarbons for hydrogen production and fuel cell applications

One of the most attractive routes for the production of hydrogen or syngas for use in fuel cell applications is the reforming and partial oxidation of hydrocarbons. The use of hydrocarbons in high temperature fuel cells is achieved through either external or internal reforming. Reforming and partial oxidation catalysis to convert hydrocarbons to hydrogen rich syngas plays an important role in fuel processing technology. The current research in the area of reforming and partial oxidation of methane, methanol and ethanol includes catalysts for reforming and oxidation, methods of catalyst synthesis, and the effective utilization of fuel for both external and internal reforming processes. In this paper the recent progress in these areas of research is reviewed along with the reforming of liquid hydrocarbons, from this an overview of the current best performing catalysts for the reforming and partial oxidizing of hydrocarbons for hydrogen production is summarized

ผลของชนิดเกลือและวิธีการล้างต่อสมบัติของเจลซูริมิและความคงตัวระหว่างการแช่เยือกแข็งของซูริมิปลาเข็มทอง

Thesis (M.Sc., Food Science and Technology)--Prince of Songkla University, 201

Brainstem Seizures and Associated Cardiorespiratory Depression Following Intrahippocampal 4-AP Application in Freely Moving Rats

Cardiorespiratory dysfunction during or after seizures may contribute to hypoxic brain damage or, in some cases, sudden unexpected death in epilepsy (SUDEP). Disruption of lower brainstem cardiorespiratory systems by seizures are postulated to impair respiratory and cardiac function. Here, I explored the effects of brainstem seizures on cardiorespiratory function using a rat model of intrahippocampal 4-aminopyridine (4-AP)-induced acute recurrent seizures. I hypothesize that seizures, focally initiated in the hippocampus, become generalized and propagate into the brainstem, disrupting brainstem function leading to cardiorespiratory depression. Animal mortality is associated with brainstem seizures which cause respiratory arrest followed by cardiac arrest. Hippocampal, cortical and caudal dorsomedial brainstem electrographic recordings together with cardiorespiratory monitoring were conducted in freely moving rats. Increased respiration rate but unchanged heart rate occurred during the seizures in the hippocampus and cortex. Status epilepticus (SE) without brainstem seizures increased respiration and heart rates whereas SE with intermittent brainstem seizures induced repeated cardiorespiratory depression leading to death. Respiratory arrest prior to asystole was a terminal event. Phenytoin (100 mg/kg, i.p.) terminated brainstem seizure-induced cardiorespiratory depression and prevented death in 5/6 rats. Focal electrical stimulation of the brainstem also suppressed cardiorespiratory parameters. I conclude that seizure propagation to the brainstem produces cardiorespiratory depression related to mortality. Although cardiorespiratory depression was observed during SE, I hypothesize that the mechanisms causing death in my model are shared with spontaneous seizures associated with SUDEP. Finally cross frequency coupling and phase coherence features were able to identify different seizure states. These variables may help elucidate the network mechanisms that lead to brainstem seizure generation.Ph.D.2020-11-19 00:00:0

Enhanced catalytic performance of Ni/Α-Al2O3 catalyst modified with CaZrO3 nanoparticles in steam-methane reforming

Ni/α-Al2O3 catalysts containing CaZrO3 nanoparticles as a promoter were prepared by sequential impregnation for H2 production from steam-methane reforming. The effects of different loadings of CaZrO3 nanoparticles from 0 to 15 wt% on the catalytic performance of Ni/α-Al2O3 catalysts in steam-methane reforming were studied. The Ni/α-Al2O3 catalysts containing 15 wt% CaZrO3 nanoparticles provided the highest H2 yield due to facilitative steps of enormous steam adsorption-dissociation at the sites of oxygen vacancies on the surface of CaZrO3 nanoparticles. The existence of facilitative steps created additional H+ and OH− enhancing both H2 yield and the gasification of deposited carbon, respectively. The tests of steam-methane reforming at low S/C ratio of 1/3 for 97 h revealed that the catalytic performance of CaZrO3-modified Ni/α-Al2O3 catalysts was higher than that of the unmodified Ni/α-Al2O3 catalyst. Interestingly, at high S/C ratio of 3 excessive steam adsorption at the oxygen vacancies on CaZrO3 nanoparticles resulted in highly competitive adsorption between steam and methane decreasing CH4 dissociation. The results suggested that in the steam-methane reforming, optimum S/C ratios for the CaZrO3-modified Ni/α-Al2O3 catalysts were relatively lower than those for the unmodified Ni/α-Al2O3 catalyst due to excellent steam adsorption-dissociation capability for CaZrO3 nanoparticles

Performance evaluation of novel PVDF-Cloisite 15A hollow fiber composite membranes for treatment of effluents containing dyes and salts using membrane distillation

The present study reports the performance of a novel PVDF-Cloisite 15A hollow fiber composite membrane for the treatment of effluents containing dyes and salts through a direct contact membrane distillation (DCMD) process. The performance of the membrane was evaluated by varying several important parameters during the DCMD process which included feed properties (type of dyes, dye and salt concentration) and process conditions (feed temperature and flow rate). The experimental results showed that the in-house made membrane was able to achieve stable fluxes and excellent dye rejections (>97%) when tested with feed solutions containing dyes of different classes and molecular weights (MW), except crystal violet (CV) dye. The lower rejection resulting from a CV-containing feed is likely due to its small MW coupled with its high diffusion rate in aqueous solution. With respect to feed concentration, it is found that an increase in salt concentration in the feed solution had a negligible effect on the membrane separation performance. Increasing the dye concentration in the feed however led to lower membrane water flux owing to the deposition of dye particles on the membrane surface which resulted in severe fouling. Meanwhile, increasing the feed temperature and its flow rate could improve the membrane flux without affecting the permeate quality. When tested using a dyeing solution containing 50 ppm acid red and 1.0 M NaCl, the membrane flux was reported to enhance by 200% and 25% on increasing the feed temperature from 50 to 90 °C and the flow rate from 0.010 to 0.023 m s-1, respectively