Bench-scale Unit Research Articles

Microwave assisted pyrolysis of Indian and Indonesian coals and product characterization

In this study, microwave assisted pyrolysis of Indian and Indonesian coals are investigated to evaluate the liquid fuel potential of these two coal varieties. Microwave pyrolysis experiments were conducted in a bench scale unit, and the effects of various parameters such as microwave power, coal particle size and coal:susceptor ratio on product yields and oil composition were thoroughly evaluated. The oil composition was semi-quantitatively analyzed using gas chromatography–mass spectrometry. Oil yield was not significantly affected by microwave power and initial particle size of coal. The oil yields were 23±2wt.% and 35±3wt.% for Indian and Indonesian coals, respectively, on dry ash free basis. The use of graphite as susceptor enhanced the heating rate although the oil and gas yields were not significantly affected. Indian coal oil contained a mixture of monoaromatics, naphthalenes, polyaromatics and phenolic compounds, while Indonesian coal oil was rich in only phenolic compounds. The addition of graphite promoted the formation of long chain alkanes and alkenes in C12–C20 range for both the coal varieties. Hydrogen gas constituted a major fraction of the non-condensable gases. Higher heating values of coal oils were estimated to be 33–39MJkg−1, while that of coal chars were in the range of 19–22MJkg−1.

Optimization and modeling of diananofiltration process for the detoxification of ligno-cellulosic hydrolysates - Study at pre-industrial scale

In order to improve bioethanol production by yeast fermentation of lignocellulosic hydrolysates, sugar/inhibitor separation by nanofiltration was studied on a bench-scale unit equipped with a spiral-wound membrane. Therefore, a model solution containing 3 sugars and 4 inhibitors was treated with two previously selected membranes (NF270 from DOW Filmtec and DK from GE Osmonics). Both membranes led to high sugar rejection, especially at high permeate flux (>90% for glucose and arabinose and >85% for xylose). Although its water permeability was smaller, DK membrane was preferred for its higher transmission of the inhibitors, especially for the largest ones (vanillin and 5-hydroxymethyl furfural), ensuring a better detoxification level. Diafiltration was applied to improve sugar purity of the treated hydrolysate. With a diavolume equivalent to 1.25 times that of the feed, acetic acid concentration was divided by 5 and brought back to concentrations lower than 1gL−1. A simulation model was proposed to predict the diavolume to apply, depending on the initial concentrations. Finally, processed hydrolysates were tested for the fermentation ability with a Pichia stipitis species. Fermentation tests showed that diafiltration followed by concentration led to retentates as fermentable as an equivalent pure sugars solution.

Catalytic Flash Pyrolysis of Biomass Using Different Types of Zeolite and Online Vapor Fractionation

Bio-oil produced from conventional flash pyrolysis has poor quality and requires expensive upgrading before it can be used as a transportation fuel. In this work, a high quality bio-oil has been produced using a novel approach where flash pyrolysis, catalysis and fractionation of pyrolysis vapors using two stage condensation are combined in a single process unit. A bench scale unit of 1 kg/h feedstock capacity is used for catalytic pyrolysis in an entrained down-flow reactor system equipped with two-staged condensation of the pyrolysis vapor. Zeolite-based catalysts are investigated to study the effect of varying acidities of faujasite Y zeolites, zeolite structures (ZSM5), different catalyst to biomass ratios and different catalytic pyrolysis temperatures. Low catalyst/biomass ratios did not show any significant improvements in the bio-oil quality, while high catalyst/biomass ratios showed an effective deoxygenation of the bio-oil. The application of zeolites decreased the organic liquid yield due to the increased production of non-condensables, primarily hydrocarbons. The catalytically produced bio-oil was less viscous and zeolites were effective at cracking heavy molecular weight compounds in the bio-oil. Acidic zeolites, H-Y and H-ZSM5, increased the desirable chemical compounds in the bio-oil such as phenols, furans and hydrocarbon, and reduced the undesired compounds such as acids. On the other hand reducing the acidity of zeolites reduced some of the undesired compounds in the bio-oil such as ketones and aldehydes. The performance of H-Y was superior to that of the rest of zeolites studied: bio-oil of high chemical and calorific value was produced with a high organic liquid yield and low oxygen content. H-ZSM5 was a close competitor to H-Y in performance but with a lower yield of bio-oil. Online fractionation of catalytic pyrolysis vapors was employed by controlling the condenser temperature and proved to be a successful process parameter to tailor the desired bio-oil properties. A high calorific value bio-oil having up to 90% organics was produced using two staged condensation of catalytic pyrolysis vapor. Zeolite-based acidic catalysts can be used for selective deoxygenation, and the catalytic bio-oil quality can be further improved with staged vapor condensation.

In situ performance of various metal doped catalysts in micro-pyrolysis and continuous fast pyrolysis

Catalytic fast pyrolysis (CFP) of biomass is a promising route for the production of deoxygenated liquids suitable for further conversion to fuels and/or chemicals. In this work, CFP of pine wood in a micro-pyrolysis setup and a continuously operated bench-scale fast pyrolysis unit was performed to investigate the effect of catalyst type and reactor type on the products. In total, eight zeolite catalysts (metal doped acidic, basic, and γ-alumina catalysts and their parent counterparts) were tested. In the bench-scale unit, the distribution of products including liquid organics (i.e. CFP-oil), water, char, coke, and non-condensable gases (NCGs) were measured, as well as the compositions of the CFP-oil and NCGs. CFP gives rise to the production of additional water, coke, and NCGs at the expense of CFP-oil. However, the quality of the obtained CFP-oil was altered significantly depending on the catalyst type. For all catalysts, the acidity of CFP-oils remarkably decreased with an increased deoxygenation. The best performance was obtained with the lower redox-metal containing acidic catalyst and freshly calcined metal doped basic mixed-metal oxide catalysts. Py-GC/MS results obtained with the same catalysts were found to be only partially indicative for the performance of a catalyst in CFP of biomass.

Design of a bench scale unit for continuous CO2 capture via temperature swing adsorption—Fluid-dynamic feasibility study

The design of a bench scale unit (BSU) for continuous CO2 capture via temperature swing adsorption (TSA) is introduced. The BSU comprises two, interconnected multi-stage fluidized bed columns that allow for counter-current contact of adsorbent and gas streams during adsorption and desorption, respectively. From a fluid-dynamic point of view, the system is capable to capture 100kg of CO2 per day from a feed gas stream having 5vol.% CO2 content. In order to study the fluid-dynamic operability of the proposed BSU design, a cold flow model (CFM) representing half of the BSU system was constructed and operated. The CFM consists of five consecutive stages of bubbling fluidized beds and a recirculation line that comprises a mechanical screw conveyor, a pneumatic transport riser and a gas–solids separator. A comprehensive CFM campaign that included variations of the main operating parameters was conducted using air as fluidizing agent and polystyrene particles as bed material. Pressure drops across the individual stages and along the transportation riser were continuously measured to monitor the solids distribution within the system. Results from CFM experiments showed that continuous operation of the multi-stage fluidized bed system is possible within a broad range of operating conditions. After completion of the first experimental campaign, a further test was conducted to study the expansion of the dense phase of the fluidized bed within an individual stage, using long-time exposure photography. The obtained pictures delivered qualitative explanations for the results obtained from the parameter variations conducted in the first campaign. Altogether, the CFM test campaign clearly proved the fluid-dynamic feasibility of the proposed BSU design. In a next step, the results of this study will be used to elaborate the detailed design of the actual BSU for continuous CO2 capture via temperature swing adsorption.

Continuous hydrothermal co-liquefaction of aspen wood and glycerol with water phase recirculation

Hydrothermal liquefaction is a promising technology for the conversion of a wide range of bio-feedstock into a biocrude; a mixture of chemical compounds that holds the potential for a renewable production of chemicals and fuels. Most research in hydrothermal liquefaction is performed in batch type reactors, although a continuous and energy-efficient operation is paramount for such process to be feasible. In this work an experimental campaign in a continuous bench scale unit is presented. The campaign is based on glycerol-assisted hydrothermal liquefaction of aspen wood carried out with the presence of a homogeneous catalyst at supercritical water conditions, 400°C and 300bar. Furthermore, in the experimental campaign a water phase recirculation step is incorporated to evaluate the technical feasibility of such procedure. In total, four batches of approximately 100kg of feed each were processed successfully at steady state conditions without any observation of system malfunctioning. The biocrude obtained was characterized using several analytical methods to evaluate the feasibility of the process and the quality of the product. Results showed that a high quality biocrude was obtained having a higher heating value of 34.3MJ/kg. The volatile fraction of the biocrude consisted mostly of compounds having number of carbon atoms in the C6–C12 range similar to gasoline. In terms of process feasibility, it was revealed that total organic carbon (TOC) and ash significantly accumulated in the water phase when such is recirculated for the proceeding batch. After four batches the TOC and the ash mass fraction of the water phase were 136.2 [g/L] and 12.6 [%], respectively. Water phase recirculation showed a slight increase in the biocrude quality in terms on an effective hydrogen-to-carbon ratio, but it showed no effects on the product gas composition or the pH of the water phase. The successful operation demonstrated the technical feasibility of a continuous production of high quality biocrude.

Gas-phase simulated moving bed: Propane/propylene separation on 13X zeolite

In the last years several studies were carried out in order to separate gas mixtures by SMB technology; however, this technology has never been implemented on an industrial scale. In the present work, a gas phase SMB bench unit was built and tested for the separation of propane and propylene mixtures, using 13X zeolite extrudates as adsorbent and isobutane as desorbent. Three experiments were performed to separate propane/propylene by gas phase SMB in the bench scale unit with a 4-2-2 configuration, i.e., open loop circuit by suppressing section IV (desorbent regeneration followed by a recycle). Consequently, all the experiments were conducted using an external supply of pure isobutane as desorbent. Parameters such as switching time, extract and raffinate stream flow rates were changed to improve the efficiency of the process. Experimental results have shown that it is feasible to separate propylene from propane by gas phase SMB at a bench scale and that this process is a potential candidate to replace the conventional technologies for the propane/propylene separation. The performance parameters obtained are very promising for future development of this technology, since propylene was obtained in the extract stream with a purity of 99.93%, a recovery of 99.51%, and a productivity of 114.08 kgC3H6 h−1 madsorbent−3. Propane was obtained in the raffinate stream with a purity of 98.10%, a recovery of 99.73% and a productivity of 30.42 kgC3H8 h−1 madsorbent−3. The success of the above mentioned bench scale tests is a big step for the future implementation of this technology in a larger scale.

Experimental and modelling studies on continuous synthesis and refining of biodiesel in a dedicated bench scale unit using centrifugal contactor separator technology

Continuous synthesis and refining of biodiesel (FAME) using a laboratory scale bench scale unit was explored. The unit consists of three major parts: (i) a continuous centrifugal contactor separator (CCCS) to perform the reaction between sunflower oil and methanol; (ii) a washing unit for the crude FAME with water/acetic acid consisting of a mixer and a liquid–liquid separator; and (iii) a FAME drying unit with air. The continuous setup was successfully used for a 4 h runtime without any operational issues. The CCCS was operated at an oil flow rate of 32 mL/min, rotational speed of 35 Hz, 60°C, a catalyst concentration of 1.2% w/w and a methanol flow rate of 10 mL/min. The flow rate of water (containing 1% w/w acetic acid) for the biodiesel washing unit was 10 mL/min (20°C); the air flow rate (5% humidity) was set at 12 L/min. After 4 h runtime, approximately 7 kg of refined FAME was produced from a cumulative sunflower oil feed of 7.07 kg. The ester content of the refined FAME was 98% w/w (GC). Other relevant product properties were also determined and most were shown to meet the ASTM specifications. The refining section was modelled and optimised using ASPEN software.Practical applications: Synthesis and refining of sunflower biodiesel was successfully performed in a dedicated bench scale unit using centrifugal contactor separator technology. Besides for large scale biodiesel production, this technology has particularly potential to be applied in small mobile biodiesel units due to the compact size, robustness, flexibility in operation and high volumetric productivity of the CCCS devices.Schematic representation of the continuous bench scale unit.

Oilfield produced water treatment by ceramic membranes: Bench and pilot scale evaluation

Oilfield produced water contains a significant amount of suspended solids and oil and grease that need to be almost completely removed prior to reinjection or when subsequent desalination processes are applied. For the separation of both contaminants from oilfield produced water, membrane technology has been described as a potential solution. Therefore, for this study, zirconia oxide ceramic membranes in bench and pilot scale units were used to evaluate the permeate flux behavior in long-term tests. The effect of backpulsing and backwashing procedures on the process performance was also investigated. A 36% boost of the permeate effective flux was achieved when both techniques were applied simultaneously. Based on those results and from literature information, a cost estimation for a full scale plant was obtained. Different cleaning procedures intervals were simulated and related to the process cost. The operational cost and capital expenditure for a plant capable of generating 1000m3h−1 of permeate were found to be equal to US$ 0.27/m3 and MUS$ 7.11, respectively, when the membrane renegeration interval was considered to be equal to 100h.

Effect of Long-Term Storage and Thermal History on the Gas Content of Natural Gas Hydrate Pellets under Ambient Pressure

The use of natural gas hydrate (NGH) as a natural gas transportation and storage medium is expected to meet further energy demand in the near future. To exploit NGH for industrial porposes, it is necessary to establish NGH storage systems using their self-preservation properties. In this report, NGH pellets containing CH4, C2H6, and C3H8 were produced by continuous production using a bench-scale unit and successfully stored for 3 months at 253 K under atmospheric pressure. Qualitative and quantitative analyses [phase-contrast X-ray computed tomography (CT) by means of diffraction-enhanced imaging, cryogenic scanning electron microscopy, powder X-ray diffraction, and gas chromatography] were conducted to investigate the progression of dissociation. Some of the NGH pellets were also examined for their thermal history dependence between approximately 85 and 253 K after storage for 1 day or less to assess their stability under a rapid temperature change. The internal texture of the original NGH pellets was de...

Vacuum Gas Oil Hydrocracking on NiMo/USY Zeolite Catalysts. Experimental Study and Kinetic Modeling

A bench-scale experimental unit based on a Robinson–Mahoney reactor with completely mixed gas and liquid phases was used to study the hydrocracking of a light vacuum gas oil on two base metal sulfide containing acid catalysts, characterized by their textural properties, NH3-TPD and pyridine-adsorbed Fourier-transformed infrared (Py-FTIR) acidity. The reactor effluent was analyzed in great detail by means of online gas chromatography and gas chromatography–mass spectrometry which evidenced the role of the catalyst acidity. The detailed analysis allowed the reaction scheme to be expressed at the level required by the kinetic analysis in terms of the fundamental Single Event Kinetics approach and thus drastically reduce the number of independent kinetic parameters to be determined from the experimental data. Reactor simulations illustrate the detailed predictions made possible by this approach.

Effect of chemical and biological surfactants on activated sludge of MBR system: Microscopic analysis and foam test

A bench-scale MBR unit was operated, under stressing condition, with the aim of stimulating the onset of foaming in the activated sludge. Possible synergies between synthetic surfactants in the wastewater and biological surfactants (Extra-Cellular Polymeric Substances, EPSs) were investigated by changing C/N ratio. The growth of filamentous bacteria was also discussed. The MBR unit provided satisfactory overall carbon removal overall efficiencies: in particular, synthetic surfactants were removed with efficiency higher than 90% and 95% for non-ionic and ionic surfactants, respectively. Lab investigation suggested also the importance to reduce synthetic surfactants presence entering into mixed liquor: otherwise, their presence can significantly worsen the natural foaming caused by biological surfactants (EPSs) produced by bacteria. Finally, a new analytic method based on “ink test” has been proposed as a useful tool to achieve a valuation of EPSs bound fraction.

PVDF hollow fiber and nanofiber membranes for fresh water reclamation using membrane distillation

Polyvinylidene fluoride hollow fiber and nanofibrous membranes are engineered and successfully fabricated using dry-jet wet spinning and electrospinning techniques, respectively. Fabricated membranes are characterized for their morphology, average pore size, pore size distribution, nanofiber diameter distribution, thickness, and water contact angle. Direct contact membrane distillation (DCMD) performances of the fabricated membranes have been investigated using a locally designed and fabricated, fully automated MD bench scale unit and DCMD module. Electrospun nanofibrous membranes showed a water flux as high as 36 L m−2 h−1 whereas hollow fiber membranes showed a water flux of 31.6 L m−2 h−1, at a feed inlet temperature of 80 °C and at a permeate inlet temperature of 20 °C.

Hydrodynamics of sinusoidal spacers for improved reverse osmosis performance

A key to maximizing flux and decreasing fouling in reverse osmosis (RO) is to decrease concentration polarization. This is currently partially accomplished by mesh feed spacers, but mesh spacers increase the longitudinal pressure drop and form dead zones where foulants accumulate. Alternative spacer geometry is presented here where sinusoidal flow patterns are created. Several models of RO spacer channels with varying amplitude and wavelength in their sinusoids were created for evaluation by three-dimensional computational fluid dynamics (CFD) simulations (COMSOL Multiphysics software) that included predictions of concentration polarization and flux. Results over a range of pressures and salt concentrations indicated that the more tortuous geometries (higher amplitude and shorter wavelength) induced greater local fluid velocity and decreased concentration polarization, which led to greater flux. Taylor–Goertler vortices generated in the peaks and valleys of the channels aided in mass transfer. The drawback to the sinusoidal geometry was an increased pressure drop, but one of the sinusoidal geometries tested had both a lower pressure drop and higher flux than a conventional mesh spacer. A subset of the spacer geometries was built and tested experimentally in a bench-scale RO unit. Experimental and modeling data were in good agreement, confirming the benefits of the sinusoidal spacer geometries and suggesting that CFD is an effective tool for predicting performance.

Thermochemical biomass to liquid (BTL) process: Bench-scale experimental results and projected process economics of a commercial scale process

In this paper, we examine the technological feasibility and economic viability of producing liquid fuels from biomass via thermo-chemical route. We initially present laboratory scale production results for synthesizing liquid fuels using syngas derived from biomass. The experiments showed that excellent yield of middle distillate products can be obtained from the bio-derived syngas, but it required supplementing the syngas with hydrogen due to low H2/CO ratio. The results from bench-scale liquefaction unit served as the basis for subsequent modeling and simulation of a biomass to liquid production facility which in turn is used for a preliminary economic analysis of a commercial scale facility using this technology.Two different technologies are compared; one using biomass as the sole feedstock (BTL), while the other augmented biomass derived syngas with hydrogen using the reforming process (BGTL). The idea of co-processing was suggested due to (i) hydrogen deficiency in the biomass feedstock, and, (ii) lower cost of natural gas which is rich in hydrogen. The basis for the design was 2000 metric tons of dry biomass fed per day. We did not include CO2 capture and storage in this study. However, when co-processing was employed, there was significant reduction in CO2 emissions and carbon capture from the biomass increased. A conceptual process capable of 100% feedstock carbon capture is also presented. The breakeven cost of oil (BECOP) was estimated to be $124/bbl for the BTL plant versus $95/bbl for a natural gas assisted BGTL plant using current market prices for raw material and capital equipment. With the increased availability, and falling prices of natural gas, augmentation with natural gas can provide a bridge solution in short term for an economical biomass to liquid fuel technology.

혼합냉매를 이용한 천연가스 액화공정의 제어변수 분석

천연가스 액화 공정은 상온의 천연가스를 상압 <TEX>$-160^{\circ}C$</TEX> 이하로 냉각해서 액화시키는 공정으로, 안정된 LNG 생산을 위해서는 최적의 제어 전략이 필요하다. 제어 전략을 수립할 때 가장 중요한 작업 중 하나가 공정의 분석인데, 조절 변수의 변화에 따른 제어 변수의 변화를 파악하는 것이다. 본 논문에서는 C3MR(Propane Pre-cooled Mixed Refrigerant) 공정으로 BSU(Bench Scale Unit)를 제작하여 천연가스 액화 공정을 실험하였다. 각 조절변수의 조작에 따른 유량의 변화가 공정에 미치는 영향을 알아보기 위해서 냉매의 유량변화에 따른 냉매 온도 변화 및 천연가스의 온도 변화를 분석하였고, 천연가스 자체의 유량 변화에 따른 냉매의 온도 변화를 분석함으로써 3개의 조절 변수와 공정의 제어변수들과의 관계를 알아보았다. 각 제어변수들은 독립적인 요소들이 아닌 서로 연관되어 유기적인 움직임을 보였으나, 특정 조절 변수의 변화에 따라 큰 반응을 보이는 제어 변수를 확인 할 수 있었다. The process of liquefied natural gas is less then <TEX>$-160^{\circ}C$</TEX> to natural gas by cooling at atmospheric pressure. When control strategy was made, one of the most significant is analysis of process. It is important to understand the control variable change according to manipulated variable change. In this study, we experiment natural gas liquefied process using C3MR(Propane Pre-cooled Mixed Refrigerant) process by BSU(Bench Scale Unit). We analyzed the change of refrigerant temperature and natural gas temperature according to the change of refrigerant flow rate so as to search an influence flow rate according to adjust each manipulated variables. One of the manipulated variable affected a number of control variables, but were able to confirm a control variable with a large response.

Model-based analysis of bench-scale fixed-bed units for chemical-looping combustion

The objective of this work is to compare reaction schemes and kinetic mechanisms, and simulate the dynamic behavior of chemical-looping Reducers operating with methane as the feed and nickel oxide as the oxygen carrier. A dynamic model for the reduction step of chemical-looping combustion in fixed-bed reactors is developed, on the basis of the same kinetic network to predict published experimental data of different fixed-bed reactors and data of a chemical-looping fixed-bed reactor operating at the University of Connecticut. Steam reforming, water gas shift, dry reforming, methane decomposition, and carbon gasification by carbon dioxide and steam are considered as reactions catalyzed by the reduced oxygen carrier. Heterogeneous reactions of the oxygen carrier encompass reactions with methane, carbon monoxide and hydrogen. Kinetic expressions reported in the literature are compared and their parameters are estimated on the basis of experimental data of nickel-based oxygen carriers for chemical-looping combustion of methane. Particle shrinking, molar expansion and surface area changes are accounted for in the transient plug flow reactor model. The applicability of the shrinking core and modified volumetric models, which are typically used for the description of gas–solid reactions is verified and compared against various experimental data, showing the superiority of the latter. A global mechanism and kinetic parameters that can be used to simulate CLC Reducers operating with NiO as the oxygen carrier and CH4 as the fuel are proposed. Finally, discrepancies between published data and the model accuracy for different experimental setups are discussed.

Nano Membrane Water: development of innovative hybrid processes for contaminated water treatment using nanoporous membranes

This study aims at the development of a hybrid process for the efficient treatment of water and potentially of wastewater, by the combination of ozonation and membrane filtration and the investigation of the complete ozone utilization by the employment of a novel ceramic membrane reactor concept. The advantages of the process are mainly referred to the achievement of a homogeneous (down to microscale) transfer and distribution of ozone (“bubbles aeration”) within the main body of bulk water stream, which results in very efficient oxidation. Ceramic membranes were prepared initially, in order to investigate the single filtration of groundwater; tubular shaped nonsymmetric ceramic membranes were developed and their efficiency was examined for the removal of As-loaded water. Microporous γ-Al2O3–17Fe (molar ratio Al and Fe: 1:1) membrane was found to adsorb the pollutant As(V) ions up to 95%. The combined process of ozonation and membrane filtration was examined in a bench scale unit, where ozone was added through a ceramic diffuser at low flow rates, under continuous and intermittent modes. Simulated ground and surface water containing 25 mg L-1 of kaolin and humic acid was fed to the reactor; it was found that the intermittent mode of ozone addition was beneficial over the continuous mode of operation, resulting in lower trans-membrane pressure values. However, the hybrid process of ozonation-membrane filtration resulted in a lower quality effluent with a higher Total Organic Carbon content, possibly due to the effect of ozone on organic substances: ozone resulted to the dissociation of large molecular weight compounds and the formation of smaller molecules that could easily pass through the membranes in the effluent. In addition, a new hybrid ozone-filtration unit has been constructed. In this unit, the water to be treated flows through the inner side of a tubular membrane while gaseous ozone stream flows along the outer. An appropriate pressure drop gradient causes ozone to flow towards the inner water stream through the nanopores of the ceramic membrane, causing oxidation (and decomposition) of the organic substances or complexes, which are present in the water stream. The retentate stream of the first step represents the influent to the second step where the removal of ions is achieved by ceramic membranes (ultrafiltration).

Effect of filter media size, mass flow rate and filtration stage number in a moving-bed granular filter on the yield and properties of bio-oil from fast pyrolysis of biomass

Fast pyrolysis of cassava rhizome was performed in a bench-scale fluidised-bed reactor unit incorporated with a cross-flow moving-bed granular filter. The objective of this research was to examine several process parameters including the granular size (425-1160 μm) and mass flow rate (0-12 g/min) as well as the number of the filtration stages (1-2 stages) on yields and properties of bio-oil. The results showed that the bio-oil yield decreased from 57.7 wt.% to 42.0-49.2 wt.% when increasing the filter media size, the mass flow rate and the filtration stage number. The effect of the process parameters on various properties of bio-oil is thoroughly discussed. In general, the bio-oil quality in terms of the solids content, ash content, initial viscosity, viscosity change and ageing rate could be enhanced by the hot vapour granular filtration. Therefore, bio-oil of high stability could be produced by the pyrolysis reactor configuration designed in this work.

The Effect of Boron on the Activity of Hydrotreating Co-Mo/Al2O3 Catalyst

A series of aluminum borate with various boria content were prepared. These materials were used as the supports of Co-Mo catalysts. They were characterized with respect to surface area, pore volume, and pore size distribution. The temperature programmed reduction method was used to monitor molybdenum oxide-support interaction. The results showed that the addition of boria concentration (2, 4, and 6 wt%) decreases the reducibility of the catalyst, reduction peak increase with increasing B2O3 content. Hydrodesulfurization of atmospheric gas oil was carried out over these presulfided catalysts in a bench-scale cata-test unit at 320–360°C and LHSV from 1 to 3 h−1. Hydrogen pressure and H2/HC feed ratio were kept constant at 4 MPa and 300 l/l, respectively. All Co-Mo-/AB catalysts are much more active than the conventional Co-Mo/Al2O3 catalyst on hydrodesulfurization reactions. The dispersion of the active sulfide phase of Co-Mo/Al2O3 catalyst is increased by the incorporation of adequate boria content. An optimum B2O3 content, which gives the highest activity, was found in the vicinity of 4 wt%.