Organic Liquid Yield Research Articles

The influence of harvest and storage on the properties of and fast pyrolysis products from Miscanthus x giganteus

The research investigates the fuel property variations associated with the time of harvest and the duration of storage of Miscanthus x giganteus over a one year period. The crop has been harvested at three different times: early (September 2009), conventional (April 2010) and late (June 2010). Once harvested the crop was baled and stored. Biomass properties of samples taken from different storage zones were compared. The thermochemical properties have been investigated using a range of analytical equipment including thermogravimetric analysis (TGA) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). In addition, bio-oil has been produced from the early, conventional and late harvest using a laboratory scale (300 g h−1) fast pyrolysis unit. The potential organic liquid yield (on dry basis, also excluding the reaction water generated) based on the laboratory fast pyrolysis processing undertaken in this study, was found to vary between 2.82 and 3.18 dry t ha−1 for the early and the late harvest respectively. The bio-oil organic yield was reduced by approximately 11% (0.36 t ha−1) between the early and the late harvest. Char yield was also reduced by approximately 18% (0.61 t ha−1). The highest gas yield (18.03%-1.60 t ha−1) was observed for the conventional harvest. Gas chromatography-mass spectrometry (GC-MS) analysis of the bio-oil shows that levoglucosan, methylbenzaldehyde and 1,2-benzenediol all increase as a consequence of delayed harvest. It was also observed that by delaying the harvest time the O:C atomic ratio is reduced and a more carbonaceous feedstock is produced.

The effect of hydrothermal treatment of FCC catalysts and ZSM-5 additives in catalytic conversion of biomass

Fresh fluid catalytic cracking (FCC) catalysts and ZSM-5 additives were hydrothermally treated with 100% steam at 732°C (1350°F) and 788°C (1450°F) for 4h in a fluidized bed reactor. The catalytic pyrolysis of hybrid poplar wood with fresh and steam treated catalysts was conducted in a 50mm bench scale bubbling fluidized bed reactor at 475°C and a weight hourly space velocity (WHSV) of 2h−1. BET surface area measurements showed a reduction of 24% and 34% in the surface area of the FCC catalyst after steam treatment at 732°C and 788°C respectively. The non-phosphorus based ZSM-5 additive lost about 15% of its surface area after mild steaming at 732°C. However, the phosphorus impregnated ZSM-5 additive was not affected at both steaming conditions. The hydrothermal treatment of the catalysts influenced the catalytic product distribution and the quality of the bio-oil. The steamed FCC catalyst produced higher organic liquid and gas yields and lower formation of coke and water. The viscosity and the density of the bio-oils produced from the steamed FCC catalyst were lower than those produced with the fresh FCC catalyst. In the case of the ZSM-5 additives, the steam treatment affected only the organic liquid and gas yields. The organic liquid yield increased and the gas yield decreased. Steaming of the ZSM-5 additive did not show any effect on the char/coke yield as was seen with the FCC catalyst due to the lower tendency of ZSM-5 to form coke. The GC analysis of the product gases suggested that steam treatment influenced the catalyst selectivity in the formation of CO, CO2, H2, CH4 and C2C5 hydrocarbons. The 13C NMR analysis of the bio-oil showed generally that steaming of the FCC catalyst increased the selectivity for the production of aromatic hydrocarbons.

One‐Step Hydrotreatment of Vegetable Oil to Produce High Quality Diesel‐Range Alkanes

A one-step hydrotreatment of vegetable oil combining deoxygenation and isomerization to directly produce low cloud point, high quality diesel is devised. The Pt/zeolite bifunctional catalysts prepared by using SAPO-11 and ZSM-22 zeolites as supports are used in this process. Catalytic reactions are conducted in a fixed-bed reactor under a hydrogen atmosphere. Over the bifunctional catalyst, 100 % conversion of soybean oil is obtained at 357 °C, 4 MPa, and 1 h(-1), and 80 % organic liquid yield is achieved, which is close to the maximum theoretical liquid yield. In the organic products, the alkanes selectivity is 100 % with an i-alkanes selectivity above 63 %. NH(3)-temperature programmed desorption (TPD), pyridine IR spectroscopy, and other characterization techniques are used to study the effect of the support acidity on the reaction pathway. Over the Pt/zeolite bifunctional catalyst with less strong Lewis acid sites, the reaction proceeds via the decarboxylation plus decarbonylation pathway. This one-step method provides a new strategy to produce low cloud point, high quality diesel from biomass feedstock in a more economic and attractive way.

A KINETIC MODEL FOR THE PRODUCTION OF LIQUIDS FROM THE FLASH PYROLYSIS OF BIOMASS

A kinetically based prediction model for the production of organic liquids from the flash pyrolysis of biomass is proposed. Wood or other biomass is assumed to be decomposed according to two parallel reactions yielding liquid tar and ( gas + char) The tar is then assumed to further react by secondary homogeneous reactions to form mainly gas as a product The model provides a very good agreement with the experimental results obtained using a pilot plant fluidized bed pyrolysis reactor The proposed model is shown to be able to predict the organic liquid yield as a function of the operating parameters of the process, within the optimal conditions for maximizing the tar yields, and the reaction rate constants compare reasonably well with those reported in the literature

The continuous flash pyrolysis of biomass

AbstractA continuous atmospheric pressure flash pyrolysis process for the production of organic liquids from cellulosic biomass has been demonstrated at a scale of 1–3 kg/hr of dry feed. Organic liquid yields as high as 65–70% of the dry feed can be obtained from hardwood waste material, and 45–50% from wheat straw. The fluidized sand bed pyrolysis reactor operates on a unique principle so that char does not accumulate in the bed and treatment of the sand is not necessary. The product gas, about 15% of the yield, has a medium heating value. The liquid product is an acidic fluid, which pours easily and appears to be stable. A preliminary economic analysis suggests that if the pyrolysis oil can be used directly as a fuel, its production cost from wood waste is probably competitive with conventional fuel oil at the present time.