Particle Size Distribution Of Biomass Research Articles

Influence of bed material on biomass gasification in fluidized beds via a TFM-DEM hybrid model

In the biomass gasification process, mixing and segregation behaviors of fuel particles and bed materials greatly influence the performance. In this work, the Two-Fluid Model-Discrete Element Method (TFM-DEM) hybrid model is employed to evaluate the impact of bed material on biomass gasification in a fluidized bed reactor, where fuel particles and bed material particles are described by the Lagrangian method and Eulerian method respectively. The biomass particle size distribution is taken into consideration. The kinetic theory of rough sphere (KTRS) is employed to consider the rotation impact of bed materials. Flow behaviors of binary mixture and gas composition distribution are analyzed. The results reveal that the bed materials with greater size can hinder the particle mixing behaviors and make the biomass particles concentrate on the bed surface so as to increase the non-uniformity of temperature distribution in the bed. A good fluidization with smaller bed material particles is beneficial to hydrogen production.

Effects of chemical composition of Miscanthus sacchariflorus var. No. 1 on pelletizing, focusing on optimal pressure and compression ratio

Pelletizing characteristics were investigated according to the chemical composition and particle size distribution of biomass. Particularly, biomass fractionation was performed to obtain extractive-free, holocellulose, and Klason lignin fractions. Pelletizing was conducted with each biomass fraction. The particle size distribution, chemical composition, and fuel properties differed depending on the biomass fraction. Regarding fuel properties, Klason lignin presented a higher carbon content (63.27 %), gross calorific value (25.5 MJ/kg), and thermostability compare to the other fractions. However, the gross calorific value was low for holocellulose (17.4 MJ/kg). Pelletizing was conducted to produce pellets with a density of 1200 kg/m3 using a single pellet press. Optimal pressure was calculated using the Jones model at the density of 1200 kg/m3. The raw material required high pressure (178 MPa) to produce pellets, whereas the pellets of holocellulose were produced with at low pressure (59 MPa). The compression ratio (ratio between the length and diameter of the die: L/D ratio) was calculated via regression analysis, while optimal and discharge pressures were kept constant. This compression ratio was low for Klason lignin, at 3.3, and it was the highest for holocellulose, at 9.8. Additionally, pelletizing was conducted at a certain particle size (250−500 μm) to investigate the influencing factors between chemical composition and particle size for pelletizing. The composition of biomass affected the pelletizing rather than the particle size.

Effect of Biomass Carbonization on the Grinding of Coal/Biomass Mixtures.

To increase the co-firing ratio of biomass in existing pulverized coal-fired power plants, biomass should be pulverized to obtain a particle size suitable for combustion. However, evaluation of the particle size distribution of each coal and biomass mixture via traditional fuel analysis is difficult. Because coal does not contain neutral sugars, the particle size distribution of biomass in the mixture can be estimated based on its neutral sugar content. The current study was conducted to evaluate the effect of biomass carbonization on the grinding process via neutral sugar analysis. Mixtures of coal and carbonized pine chips with three different degrees of carbonization were prepared and ground using a Hardgrove grindability index mill. In the pulverized mixtures of low carbonized biomass and coal, the biomass content at all particle size ranges was nearly the same as that of the input feedstock. As the degree of biomass carbonization increased, the biomass content in the mixture of large particle sizes was decreased, whereas it was increased in the mixture of small particle sizes. The current study indicated that particle size distribution of coal and biomass in the pulverized mixture depends on the degree of carbonization of biomass.

Effect of quorum quenching on EPS and size-fractioned particles and organics in anaerobic membrane bioreactor for domestic wastewater treatment

Quorum quenching (QQ) has been applied as a promising membrane fouling control strategy for anaerobic membrane bioreactors (AnMBRs). Nevertheless, long-term operation of AnMBRs for real domestic wastewater (DWW) treatment needs to be systematically studied to evaluate comprehensive membrane fouling mechanisms and bioprocess performance. In this study, the impact of QQ on membrane fouling was investigated using a quorum quenching AnMBR (QQAnMBR) deploying a bead-entrapped facultative quorum quenching consortium (FQQ) to treat DWW. FQQ was shown to prolong membrane filtration operation by an average of 75%. Reduced proteins (p < 0.005) and carbohydrates (p < 0.005) in the extracellular polymeric substances (EPS) of mixed liquor (ML) were key differentiators that led to lower cake layer (CL) formation. Additionally, reduced biopolymers production (p < 0.05) in EPS improved sludge dewaterability. The findings suggested that QQ could alter fluorescent microbial metabolites of both EPS and CL as unveiled by excitation-emission matrix spectra pattern. Furthermore, colloidal particles (i.e., particles with size larger than 0.45 μm in ML supernatants) production was retarded by QQ, thereafter, also contributed to the reduced CL formation. Pore blockage was slightly increased by QQ, which might be attributed to pore blockage by large (∼230 nm) and small organic compounds (∼51 nm) in soluble microbial products (SMP). However, QQ had no significant impact on organic concentration of SMP, and QQ was not associated with particle size distribution of biomass. QQ performance was further affirmed through suppressed production of C4-HSL, 3-OXO-C6-HSL, and C6-HSL. The overall AHLs degradability of FQQ was well-maintained even after five membrane service cycles (total operation of 70 d). Moreover, QQ had no compromised impact on treatment performance (i.e., chemical oxygen demand (COD) removal and methane yield). Collectively, this study bridged the knowledge gap to bring forward QQ technology in AnMBR for widespread domestic wastewater treatment application.

Laboratory studies on the influence of biomass particle size on pyrolysis and combustion using TG GC/MS

The agriculture residues and energy crops have significant energy potential, which is not enough used so far. The agriculture production in Poland, and other countries of EU, gives a huge amount and variety of agriculture wastes. Whereas, energy crops characterise large annual growth at low-quality soil and high energy yields per unit of area. For this study three different agriculture biomass and two energy crops were selected. The samples were characterized in terms of their proximate and ultimate analysis. The main aim of this paper was to investigate the influence of biomass particle size distribution on the combustion and pyrolysis processes using thermogravimetric analysis (up to 600 °C at 5, 10 and 20 K/min or 50 K/min heating rate). Two fractions of biomass samples were investigated, smaller (S) size of major fraction smaller than 0.09 mm and sample of particle size smaller than 0.425 mm named larger (L). The gaseous products generated during pyrolysis process were analysed with GC/MS. Additionally, the kinetics analysis of studied processes was performed. Finally, it was found the particle size influences on the TG/DSC results and consequently significantly on the activation energy of combustion and slightly on pyrolysis of studied biomass samples.

Particulate size of microalgal biomass affects hydrolysate properties and bioethanol concentration.

Effective optimization of microalgae-to-bioethanol process systems hinges on an in-depth characterization of key process parameters relevant to the overall bioprocess engineering. One of the such important variables is the biomass particle size distribution and the effects on saccharification levels and bioethanol titres. This study examined the effects of three different microalgal biomass particle size ranges, 35 μm ≤ x ≤ 90 μm, 125 μm ≤ x ≤ 180 μm, and 295 μm ≤ x ≤ 425 μm, on the degree of enzymatic hydrolysis and bioethanol production. Two scenarios were investigated: single enzyme hydrolysis (cellulase) and double enzyme hydrolysis (cellulase and cellobiase). The glucose yield from biomass in the smallest particle size range (35 μm ≤ x ≤ 90 μm) was the highest, 134.73 mg glucose/g algae, while the yield from biomass in the larger particle size range (295 μm ≤ x ≤ 425 μm) was 75.45 mg glucose/g algae. A similar trend was observed for bioethanol yield, with the highest yield of 0.47 g EtOH/g glucose obtained from biomass in the smallest particle size range. The results have shown that the microalgal biomass particle size has a significant effect on enzymatic hydrolysis and bioethanol yield.

On-line particle sizing of pneumatically conveyed biomass particles using piezoelectric sensors

In recent years the firing of biomass at existing or new power plants has been widely adopted as one of the main technologies for reducing greenhouse gas emissions from power generation. The particle size distribution of pneumatically conveyed biomass correlates closely with combustion efficiency and pollutant emissions and should therefore be monitored continuously.In this paper, an instrumentation system based on a polyvinylidene difluoride (PVDF) piezoelectric film sensor is proposed, to achieve on-line continuous measurement of biomass particle size distribution. The sensor is attached to an impact bar protruding into the biomass particle flow. The relationship between the resulting impact signals and particle size is modelled mathematically, allowing particle size distribution to be inferred. Experimental work, undertaken with willow chips and miscanthus chips, has allowed both the effectiveness of the on-line particle sizing system and the validity of the mathematical model to be evaluated. The results indicate that the system has good linearity and repeatability.

Toward Long Solids Retention Time of Activated Sludge Processes: Benefits in Energy Saving, Effluent Quality, and Stability

The activated sludge process is the most common method of secondary municipal wastewater treatment; solids retention time (SRT) is the key control parameter for this process. Typically, operating at long SRT is considered only for nitrification, but there are additional benefits of high SRT operation. This paper presents experimental and literature evidence to demonstrate three major additional benefits of long SRT operation: increased oxygen transfer efficiency; improved biomass particle size distribution, which results in more efficient clarification with fewer effluent particles and suspended solids; and enhanced removal of many emerging contaminants such as pharmaceuticals, personal care products, and endocrine disrupting compounds. This paper presents experimental results from several treatment plants that showed increasing oxygen transfer efficiency and particle size with increasing SRT, and evidence documenting improved removal of emerging contaminants and biodegradable organic carbon. A long-term survey of three treatment plants concludes that operating at higher SRT is not as energy intensive as typically assumed.

Sedimentological evolution in an UASB treating SYNTHES, a new representative synthetic sewage, at low loading rates

The changes in the sedimentological attributes of the sludge bed in an upflow anaerobic sludge blanket (UASB) reactor fed with a low-strength wastewater mimicking raw domestic sewage were assessed in this study. The reactor was inoculated with 250 ml of granular sludge from a full-scale UASB reactor. The organic loading rate (OLR) varied from 1 to 2 g COD/l d. During the half-year long study, the reactor was operated at hydraulic retention times (HRT s) of 4.8 and 10 h, at 33 °C. Sludge sedimentology showed that the original granular sludge experienced serious instability and disintegration, leading to a much finer final grain assemblage, mainly due to substrate transfer limitation and cell starvation at the interior of larger granules. With time, the size uniformity tended to decrease, sphericity tended to increase, the skewness of the granule size distribution became negative, and the kurtosis became peaked and leptokurtic. In spite of the observed size reduction, reactor efficiency increased to a COD total removal of 96%. Biomass (sludge) yield was 0.012 g VS/g COD removed. The CH 4 content of the biogas was high (up to 96%). This study thus highlights the treatment of a new type of wastewater with the deployment of the UASB reactor. It also reports the evolutionary trend of the biomass particle size distribution, making reference to a classic sedimentological appraisal.