Tharapong Vitidsant

Conversion of used vegetable oils to liquid fuels and chemicals over HZSM-5, sulfated zirconia and hybrid catalysts

Thailand’s food manufacturing uses about 47 Million liters per year of vegetable oil. Used vegetable oil is classified as waste, but has potential for conversion into liquid fuel. This research studied the catalytic conversion of used vegetable oil to liquid fuel, where investigation was performed in a batch microreactor over a temperature range of 380–430 °C, initial pressure of hydrogen gas over 10–20 bars, and reaction time of 45–90 minutes. Catalysts such as HZSM-5, Sulfated Zirconia and hybrid of HZSM-5 with Sulfated Zirconia were used to determine the conversion and yield of gasoline fraction. The major products obtained were liquid products, hydrocarbon gases and small amounts of solids. Liquid products were analyzed by simulated distillation gas chromatograph and the product distribution was obtained. Hybrid catalyst HZSM-5 with Sulfated Zirconia showed the highest yield of gasoline with a 26.57 wt% at a temperature of 430 °C, initial hydrogen pressure at 10 bars, and reaction time of 90 minutes in the ratio of hybrid HZSM-5 with Sulfated Zirconia at 0.3: 0.7.

Catalytic steam reforming of biomass-derived tar for hydrogen production with K 2 CO 3 /NiO/ γ -Al 2 O 3 catalyst

A major problem of using Ni-based catalysts is deactivation during catalytic cracking and reforming, lowering catalytic performance of the catalysts. Modification of catalyst with alkali-loading was expected to help reduce coke formation, which is a cause of the deactivation. This paper investigated the effects of alkali-loading to aluminasupported Ni catalyst on catalytic performance in steam reforming of biomass-derived tar. Rice husk and K2CO3 were employed as the biomass feedstock and the alkali, respectively. The catalysts were prepared by a wet impregnation method with γ-Al2O3 as a support. A drop-tube fixed bed reactor was used to produce tar from biomass in a pyrolysis zone incorporated with a steam reforming zone. The result indicated that K2CO3/NiO/γ-Al2O3 is more efficient for steam reforming of tar released from rice husk than NiO/γ-Al2O3 in terms of carbon conversion and particularly hydrogen production. Effects of reaction temperature and steam concentration were examined. The optimum temperature was found to be approximately 1,073 K. An increase in steam concentration contributed to more tar reduction. In addition, the K2CO3-promoted NiO/γ-Al2O3 was found to have superior stability due to lower catalyst deactivation.

Active and regioselective rhodium catalyst supported on reduced graphene oxide for 1-hexene hydroformylation

Alkene hydroformylation with syngas (CO + H2) to produce aldehydes is one of the most important chemical reactions. However, designing heterogeneous catalysts to realize comparable performance with mature homogeneous catalysts is challenging. In this report, a reduced graphene oxide (RGO) supported rhodium nanoparticle (Rh/RGO) catalyst was successfully prepared via a one-pot liquid-phase reduction method and first applied in 1-hexene hydroformylation. 1-Hexene hydroformylation reaction under different reaction conditions with this Rh/RGO catalyst was investigated in detail. Low reaction temperature and short reaction time effectively enhanced the n/i (normal to iso) ratio of heptanal in the products. The catalytic performance of the Rh/RGO catalyst was also compared with those of Rh supported on other carbon materials, including activated carbon and carbon nanotubes (Rh/AC and Rh/CNTs). The results showed that the Rh/RGO catalyst exhibited the highest 1-hexene conversion and the largest n/i ratio of 4.0 among the tested catalysts. The special 2D nanosheet structure of the Rh/RGO catalyst, rather than the 3D porous and 1D nanotube structures of Rh/AC and Rh/CNTs, respectively, principally contributed to its excellent catalytic performance. These findings disclosed that reduced graphene oxide could be a promising catalyst support for designing heterogeneous hydroformylation catalysts.

Synthesis of char, bio-oil and gases using a screw feeder pyrolysis reactor

In this study, char, bio-oil and gases were synthesized with a continuous pyrolysis process from residual plants consisting of Cogongrass and Manilagrass at temperatures in the range of 400–550°C, with a feed rate of 150, 350, and 550 rpm (r min−1). The product yield calculation showed that the liquid yield was highest at 53.56%, at 350 rpm. After separation of the bio-oil from liquid phase, the bio-oil was found to have components of approximately 33.38%, of which the solid yield (char) was highest at 27.35%, at 350 rpm, and the gas yield was highest at 43.60%, at 150 rpm. This indicates that biomass from residual plants materials produced good yields because of low solid and gas yields while having high liquid yield.

Ruthenium promoted cobalt catalysts prepared by an autocombustion method directly used for Fischer–Tropsch synthesis without further reduction

Ru promoted Co/SiO2 Fischer–Tropsch synthesis (FTS) catalysts with high reduction levels were synthesized through an autocombustion method using citric acid (CA) as a reductant and nitrate ions as oxidants. The as-synthesized catalysts were used directly in FTS reaction without further reduction. The effects of the ruthenium promoter, citric acid contents and reductant types on the catalyst structures and FTS performance were systematically studied. Results indicated that the introduction of a small amount of Ru (1 wt%) improved the reduction and dispersion of cobalt during the autocombustion process, and significantly enhanced the FTS activity. The CO conversion of the catalyst increased rapidly from 0.8 to 41.4% after Ru promotion. The citric acid contents (molar ratio of citric acid to nitrates: CA/N) in the precursor also played an important role in controlling the structures and FTS performance of the catalysts. With the increase of CA/N, the metal reduction level increased and the Co crystalline size decreased but the activity of the catalyst first increased and then decreased with gradually increasing CA/N. An excessive amount of the reductant could result in more residual carbon species and decrease the activity of the catalyst. For different types of reductants (at the same molar ratio of reductants to nitrates), the catalyst prepared by citric acid exhibited the highest activity whereas the catalyst synthesized by oxalic acid showed the lowest methane selectivity. The Ru promoted cobalt catalysts prepared by the autocombustion method, which omits the complex and high energy consumption reduction process, can be used directly for highly efficient FTS and thus will be more promising in the future.

Comparative Study of Some Physical and Chemical Properties of Bio-Oil from Manila Grass and Water Hyacinth Transformed by Pyrolysis Process

The analyses of the physical and chemical properties of bio-oil by pyrolysis, which takes place at temperatures in the range of 450-600°C, were to compare the quality of bio-oil extracted from different weeds that is, 1) Manila grass (Zoysia Matrella (L.) Merr) (MG) and 2) Water hyacinth (Eichhornia crassipes (Mart.) Solms) (WH). The preliminary analyses of biomass by proximate analysis. The results showed that biomass extracted from both weeds had good qualities because of low moisture content and high fixed carbon. MG found carbon content of 30.77%. While WH was 29.70%. The analysis of bio-oil can found the heating values of bio-oil from MG were difference from bio-oil obtained from WH, both held that there was in the Heating Value of high-level or better standards, especially bio-oil obtained from the MG have a heating value of about 32 MJ/Kg (at 500 °C). The content of sulfur quantity are found that bio-oil from the MG have lowest a sulfur quantity 0.26 wt.% at 400 oC; similarly; bio-oil from the WH have lowest a sulfur quantity 0.27 wt.% at 400 oC. The amount of carbon in the bio-oil obtained from MG and bio-oil obtained from WH was 55.57 wt.% and 55.03 wt.%, respectively., carbon was relatively high in both weeds. Hence; In this research are concerns the feeding rate, the control gas flow, the temperatures in reactor and reactor operate. MG and WH can produce hi quality of bio-oil and two weeds of resist in Thailand can be also used to generate the other fuel energy in the future.

Catalytically active supercritical fluid to accelerate methanol synthesis

Supercritical phase 2-butanol significantly increased the conversion of methanol synthesis from syngas not only by the conventional promotion effect of supercritical fluid but also by the catalytic effect of 2-butanol solvent itself, breaking through the thermodynamic limitation of this reaction effectively.

Bio-oil synthesis by pyrolysis of cogongrass ( Imperata Cylindrica )

We have studied thermal pyrolysis of cogongrass (Imperata cylindrica) at 400°C, 450°C, and 500°C. We have studied the effect of temperature on the yield of solid, liquid, and gaseous pyrolysis products. The maximum yield (33.67%) of liquid product (bio-oil) is obtained at 500°C. The bio-oil contains oxygen-containing compounds with hydroxyl and carboxyl groups: phenol, 2,6-dimethoxyphenol, 2-methoxyphenol, 2-methylphenol, 4-ethyl-2-methoxyphenol, etc.

Accelerated methanol synthesis in catalytically active supercritical fluid

Abstract The conversion of methanol synthesis was significantly increased when supercritical 2-butanol was used. According to the property of a supercritical fluid, which facilitates heat and product removal, supercritical 2-butanol conventionally promoted the conversion of the methanol synthesis from syngas. Furthermore, supercritical 2-butanol, used as a solvent, had a catalytic effect accelerating a new reaction route. The combination of supercritical fluid and catalytic solvent effects broke through the thermodynamic limitation of the reaction efficiency.

Direct fabrication of catalytically active FexC sites by sol–gel autocombustion for preparing Fischer–Tropsch synthesis catalysts without reduction

Fe-based Fischer–Tropsch synthesis (FTS) catalysts, promoted by copper and potassium, were directly prepared through a novel modified sol–gel autocombustion without further reduction. It was disclosed that the citric acid contents controlled the reduction/carburization of the catalyst, and the performance of FTS reaction was investigated. The molar ratio of citric acid to nitrates (denoted as CA/N) played a noteworthy role in the phase change of the Fe active sites and catalytic performances of the catalysts. Adding CA not only considerably improved the Fe reduction/carburization during the preparation but also the FTS catalytic performance even without a reduction process. Enhancement of the CA/N molar ratio resulted in the increase of the reducibility of catalysts. However, the FTS performance increased first and then decreased because an unnecessary reductant could lead to accumulation of the carbonic residual on the catalyst surface and decreases the catalyst performance for FTS. The FeCuK catalysts prepared using the sol–gel autocombustion method with CA as a reductant could achieve a high FTS performance without further reduction; therefore, this method could be widely applied in designing other metallic nanoparticle catalysts.