Bio-Energy II - Conference Program

List of speakers, talks and more

Bio-Energy II - Conference Program

List of speakers, talks and more

Impact of local fluidized bed hydrodynamics on interactions between particles and gas-liquid sprays

In the Fluid CokingTM process, heavy oil is sprayed into a downward-flowing fluidized bed of hot coke particles. A good liquid distribution on the particles is essential to achieve a high yield of desirable liquid products and avoid operating problems. This presentation shows how to modify local bed hydrodynamics to improve liquid distribution. The distribution of the injected liquid in the bed can be improved by either increasing the atomization gas flowrate or, preferably, the local fluidization velocity. Study of nozzles at different locations and inclinations identifies the dominant effects of bed hydrodynamics at the nozzle and jet tips on the distribution of liquid on solid particles. Experiments with a moving nozzle, to achieve a relative velocity between spray nozzle and fluidized particles, show that increasing the relative velocity improves liquid distribution. A model for the interactions between sprayed liquid and fluidized is proposed. When a gas-liquid spray enters a fluidized bed, it forms a jet cavity that expands as atomization gas and bubbles enter the cavity and contracts as large bubbles are periodically released from the jet tip. The model assumes that the injected liquid mixes with the solid particles displaced by the jet expansion. The model shows how increasing either the atomization gas flowrate or the local fluidization velocity improves the liquid distribution by shortening the jet expansion-contraction cycle. The model also explains how the motion of the spray nozzle relative to the fluidized bed can improve liquid distribution by preventing wet solids accumulation near the jet cavity

Using the jiggled bed reactor to develop activated carbons from biomass residues

Activated carbons are the most used adsorbent material. Their applications range from wastewater treatment, air purification, removal of contaminants and many others. According to “Global Activated Carbon Market Forecast & Opportunities 2017”, the demand for activated carbon is expected to increase more than 10% per year for the next 5 years to make it a $3 billion market by 2017. Current processes for the production of activated carbons from renewable resources do not provide valuable co-products. This presentation focuses on the conversion to activated carbon of the bio-char co-product of the pyrolysis process. Pyrolysis also provides valuable bio-oil, which is a source of valuable biochemicals and fuels. This can greatly improve the economics of the pyrolysis process and the development of bio-refineries. In this study, a number of different agricultural and forestry residues were investigated as precursors for the production of activated carbons. The activated carbons were then tested for the removal of typical pollutants. A lab scale reactor, the jiggled bed reactor, was used for this study. Its unique features such as excellent mixing and heat transfer allowed for the screening of the impact of pyrolysis conditions (ranging from fast to slow pyrolysis) and activation on the final product properties. Please click Additional Files below to see the full abstract

Development and study of measurement methods for bogging in a fluidized bed

In the Fluid CokingTM process, heavy oil is contacted with hot fluidized coke particles. If the local concentration of liquid is too high, particles may stick together, resulting in poor fluidization or even defluidization, a condition commonly known as bogging . Earlier studies, presented at Fluidization XIV, used capacitance sensors to show how bogging affects bubble properties and the distribution of liquid sprayed into a fluidized bed. The objective of this study is to identify other, more practical methods for early bogging detection. Methods using pressure measurements or active sound transmission are presented. A Kolmogorov-Smirnov test of the wavelet coefficients of pressure fluctuations, optimised with a genetic algorithm, can detect early bogging more effectively than other methods using pressure fluctuations. A major advantage of this method is that its results are not affected by moderate variations in fluidization gas velocity. The success of this new bogging detection method is explained by studying the transmission of sound of different frequencies through dry and wet fluidized beds, which could also be used to detect bogging. A theoretical model confirmed that the changes in bubble properties caused by bogging affect the transmission of sound through the fluidized bed. The geometry of the gas bubbles and their distance from the wall were measured with capacitance sensors to understand how bubble properties affect sound transmission. The propagation of sound with bubbles of various geometries was simulated with Comsol

Pyrolysis of residues from well-established biochemical processes for the production of biochar

The main objective of this work is to use pyrolysis for the production of biochar from the residues of well-established biochemical processes. The residues that were selected come from two major conversion processes: biogas digesters, and wastewater treatment facilities. These processes produce unconverted lignin-rich residues, made of biomass components that are refractory to biochemical conversion. Pyrolysis is an aggressive thermochemical conversion process that is ideally suited to such residues. The desired biochar characteristics were determined by the specific needs of each industrial partner. The desired traits for the biochar obtained from sewage sludge were the capture, and stabilization of heavy metals contained in the sludge, to reduce the release of heavy metals into the environment. Please click on the file below for full content of the abstract

Adhesives from biomass pyrolysis

Fast pyrolysis of waste biomass with high lignin content, such as birch wood, birch bark, hydrolysis lignin, kraft lignin or low-cost digestate from biogas production, provides oils that can be substituted for phenol in phenol-formaldehyde resins. Biomass fast pyrolysis was performed in a dedicated fluidized bed pyrolyzer that incorporated two crucial innovations: a fractional condensation train provided dry bio-oils with ~1% of moisture and much reduced acidity; autothermal pyrolysis with partial oxidation reduces operating and capital costs, as well as increasing the quality of the dry bio-oil. Dry bio-oil obtained from autothermal fast pyrolysis of kraft lignin can be used to substitute up to 80% of phenol in reacting with formaldehyde to produce wood adhesives that met International Standards, including specifications on the dry and wet mechanical strength and formaldehyde emission (Figure 1). With dry bio-oils from the low-cost residues (birch wood, birch bark, hydrolysis lignin, or digestate), the substitution level can be 50~65%. In addition, there is no need to change the hot press temperature or curing time from the current settings for pure phenol resin. The mechanical strength and formaldehyde emission levels of the bonded plywood are affected by the phenol substitution ratio, and the concentration and molecular weight of the phenolics in the dry bio-oil. Please click Additional Files below to see the full abstract