scholarly journals Experimental Investigation of the Ash Deposition Characteristics of Biomass Pretreated by Ash Removal during Co-Combustion with Sub-Bituminous Coal

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7391
Author(s):  
Dae-Gyun Lee ◽  
Min-Jong Ku ◽  
Kyeong-Ho Kim ◽  
Jae-Sung Kim ◽  
Seung-Mo Kim ◽  
...  
Keyword(s):  
Bituminous Coal ◽  
Removal Rate ◽  
Unburned Carbon ◽  
Total Biomass ◽  
Drop Tube ◽  
Ash Deposition ◽  
Biomass Ash ◽  
Internal Corrosion ◽  
Before And After ◽  
Ash Removal

Although replacing biomass, (e.g., wood chips and pellets), with thinning wood and herbaceous biomass is eco-friendly and economically advantageous, their direct utilization in plant boilers is associated with ash-related challenges, including slagging and fouling. The aim of this study is to determine the effects of ash removal treatment (ashless biomass (ALB)) in the context of solid fuel power plant boilers. Ash was removed via neutralization of metal ions and carboxylic acids contained in the biomass ash. The ash removal rate of K, Na, Cl was indicated by assessing the total biomass before and after ash removal treatment, via XRF analysis. Co-combustion with sub-bituminous coal and ALB-treated biomass was analyzed using a drop tube furnace and revealed that NOx and SOx values converged converge toward an approximate 10 ppm error, whereas the Unburned Carbon (UBC) data did not exhibit a specific trend. Factors associated with slagging and fouling, (capture efficiency (CE), and energy based growth rate (GRE)) were calculated. All biomass samples without pretreatment exhibited V-shaped variation. Conversely, for ashless biomass (ALB) samples, CE and GRE gradually decreased. Thus, the ALB technique may minimize slagging and fouling in a boiler, thus, reducing internal corrosion associated with ash deposition and enhancing the economic operation of boilers.

scholarly journals Experimental Investigation of Ash Deposit Behavior during Co-Combustion of Bituminous Coal with Wood Pellets and Empty Fruit Bunches

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2087 ◽  
Author(s):  
Tae-Yong Jeong ◽  
Lkhagvadorj Sh ◽  
Jong-Ho Kim ◽  
Byoung-Hwa Lee ◽  
Chung-Hwan Jeon
Keyword(s):  
Melting Temperature ◽  
Power Plants ◽  
Bituminous Coal ◽  
Coal Ash ◽  
Milling Process ◽  
Drop Tube ◽  
Ash Deposition ◽  
Wood Pellets ◽  
Empty Fruit Bunches ◽  
Ash Melting

In Korea, oil-palm empty fruit bunches (EFBs), which are byproducts of the crude palm-oil milling process, are among the most promising potential energy sources for power plants. However, the slagging and fouling characteristics of EFBs during combustion have not yet been fully studied. Accordingly, in this study, we investigated the fundamental ash behavior of EFBs in comparison to that of wood pellets (WPs) using a thermomechanical analyzer (TMA) and a drop-tube furnace (DTF). Ash melting and the deposition of ash particles were investigated with traditional prediction indices at several biomass blending ratios. The results demonstrated that, as the ratio of WPs to EFBs increases, the melting temperature decreases and the slagging propensity increases because of the increased biomass alkali content. Moreover, the penetration derived using the TMA shows a higher melting peak at which rapid melting occurs, and the melting temperature distribution is decreased with increased biomass blending. Conversely, the DTF results show different phenomena for ash deposition under the same blending conditions. Blend ratios approaching 10% WP and 15% EFB result in gradual decreases in ash deposition tendencies because of the lower ash contents of the co-combusted mass compared to that of the single coal ash. Further biomass addition increases ash deposition, which is attributable to ash agglomeration from the biomass. Thus, this study demonstrates that blending ratios of 10% WP and 15% EFB provide optimal conditions for co-combustion with the selected bituminous coal. In addition, it is shown that the slagging propensity of EFB is higher than that of WP owing to its ash content and simultaneous agglomeration.

Ash Deposition at Coal-Fired Gas Turbine Conditions: Surface and Combustion Temperature Effects

1992 ◽  
Vol 114 (1) ◽  
pp. 132-138 ◽  
Author(s):  
G. A. Richards ◽  
R. G. Logan ◽  
C. T. Meyer ◽  
R. J. Anderson
Keyword(s):  
Gas Turbines ◽  
Combustion Temperature ◽  
Bituminous Coal ◽  
Test Surface ◽  
Drop Tube ◽  
Ash Deposition ◽  
Surface Cooling ◽  
Deposit Surface ◽  
Temperature Combustion ◽  
Lower Temperature

A study of ash deposition from a cleaned bituminous and conventional bituminous coal is presented. An electrically heated drop tube furnace is used to burn the coal and provide deposition conditions representative of proposed coal-fired gas turbines. Variations in the combustion temperature and deposit surface temperature demonstrate that surface cooling may significantly reduce ash deposition, or may provide little benefit, depending on the combustion conditions. Lower temperature combustion produced larger ash particles, with a greater fraction of ash adhering to the deposition test surface. Although the sticking coefficient was higher at the lower combustion temperature, the deposits were readily removed. A modest numerical simulation suggests that the smallest ash particles can experience significant boundary layer cooling and may account for the reduction in sticking observed at some conditions.

scholarly journals Investigation of Ash Deposition Dynamic Process in an Industrial Biomass CFB Boiler Burning High-Alkali and Low-Chlorine Fuel

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1092
Author(s):  
Hengli Zhang ◽  
Chunjiang Yu ◽  
Zhongyang Luo ◽  
Yu’an Li
Keyword(s):  
Gas Flow ◽  
Circulating Fluidized Bed ◽  
Deposition Process ◽  
Biomass Combustion ◽  
Ash Deposition ◽  
Biomass Ash ◽  
Cfb Boiler ◽  
Third Stage ◽  
Ash Deposit ◽  
High Alkali

The circulating fluidized bed (CFB) boiler is a mainstream technology of biomass combustion generation in China. The high flue gas flow rate and relatively low combustion temperature of CFB make the deposition process different from that of a grate furnace. The dynamic deposition process of biomass ash needs further research, especially in industrial CFB boilers. In this study, a temperature-controlled ash deposit probe was used to sample the deposits in a 12 MW CFB boiler. Through the analysis of multiple deposit samples with different deposition times, the changes in micromorphology and chemical composition of the deposits in each deposition stage can be observed more distinctively. The initial deposits mainly consist of particles smaller than 2 μm, caused by thermophoretic deposition. The second stage is the condensation of alkali metal. Different from the condensation of KCl reported by most previous literatures, KOH is found in deposits in place of KCl. Then, it reacts with SO2, O2 and H2O to form K2SO4. In the third stage, the higher outer layer temperature of deposits reduces the condensation rate of KOH significantly. Meanwhile, the rougher surface of deposits allowed more calcium salts in fly ash to deposit through inertial impact. Thus, the elemental composition of deposits surface shows an overall trend of K decreasing and Ca increasing.

Mitochondrial Ca2+ uptake is important over low [Ca2+]i range in arterial smooth muscle

2002 ◽  
Vol 283 (6) ◽  
pp. H2431-H2439 ◽  
Author(s):  
Tomoko Kamishima ◽  
John M. Quayle
Keyword(s):  
Smooth Muscle ◽  
Decay Time ◽  
Removal Rate ◽  
Arterial Smooth Muscle ◽  
Carbonyl Cyanide ◽  
Before And After ◽  
Intracellular Ca ◽  
Arterial Smooth Muscle Cells ◽  
Time Required ◽  
Loaded Voltage

Mitochondrial Ca2+ uptake is usually thought to occur only when intracellular Ca2+concentration ([Ca2+]i) is high. We investigated whether mitochondrial Ca2+ removal participates in shaping [Ca2+]i signals in arterial smooth muscle over a low [Ca2+]irange. [Ca2+]i was measured using fura 2-loaded, voltage-clamped cells from rat femoral arteries. Both diazoxide and carbonyl cyanide m-chlorophenylhydrazone (CCCP) depolarized the mitochondria. Diazoxide application increased resting [Ca2+]i, suggesting that Ca2+ is sequestered in mitochondria. Over a low [Ca2+]i range, diazoxide and CCCP slowed Ca2+ removal rate, determined after a brief depolarization. When [Ca2+]i was measured during sustained depolarization to −30 mV, CCCP application increased [Ca2+]i. When Ca2+ transients were repeatedly evoked by caffeine applications, CCCP application elevated resting [Ca2+]i. Caffeine-induced Ca2+ transients were compared before and after CCCP application using the half decay time, or time required to reduce increase in [Ca2+]i by 50% ( t ½). CCCP treatment significantly increased t ½. These results suggest that Ca2+ removal to mitochondria in arterial smooth muscle cells may be important at a low [Ca2+]i.

Effect of Ash Content on Unburned Carbon and NOx Emission in a Drop Tube Furnace

2014 ◽  
Vol 38 (12) ◽  
pp. 963-969 ◽  
Author(s):  
Sang-In Kim ◽  
Byoung-Hwa Lee ◽  
Ke-Ju An ◽  
Man-Cheol Kim ◽  
Seung-Mo Kim ◽  
...  
Keyword(s):  
Ash Content ◽  
Nox Emission ◽  
Tube Furnace ◽  
Unburned Carbon ◽  
Drop Tube ◽  
Drop Tube Furnace

Study on the planarization behaviour of copper CMP utilizing a dense pattern and a global step

2005 ◽  
Vol 867 ◽  
Author(s):  
Tilo Bormann ◽  
Johann W. Bartha
Keyword(s):  
Removal Rate ◽  
Specific Pattern ◽  
Constant Density ◽  
Large Area ◽  
Before And After ◽  
Contour Evolution ◽  
Copper Cmp ◽  
To Come ◽  
Dense Pattern

AbstractThe major aim of CMP is not the removal of excess material but the planarization of the surface. Therefore the determination of the planarization length appears to be more important than the removal rate itself. It has been shown, that the planarization length is not a constant process parameter, but is related to the removal respectively to the polish time in a square root behaviour. Founded on models proposed by Boning, Ouma, et. al. we applied a sequential polish on a single quasi infinite step. The resulting profile could be simulated by a sequential convolution of the surface contour with a Gaussian transfer function.To come closer to the situation on a chip pattern we investigated the planarization behaviour on a specific pattern of the MIT854AZ copper CMP test chip, where a large area of unpatterned surface touches a pattern with a specific constant density.The 200 mm wafer samples consisted of RIE structured oxide films covered with 850 nm ECD copper. The polish was performed on a standard semiconductor manufacturing tool, using a commercial consumables set. The surface profiles were determined by a high resolution profiler within the polishing sequence. The densely patterned areas are removed within a certain polishing time while the transition point between the unpatterned and patterned area appears as a global step. The deposited copper thickness is sufficient to study the contour evolution in both phases, before and after removal of the dense pattern. The paper presents the experimental results on the contour evolution for the patterned fields as well as the global step.

Fuel Flexible Biomass Reburn Technology

2009 ◽  
Author(s):  
Guang Xu ◽  
Wei Zhou ◽  
Larry Swanson
Keyword(s):  
Particle Size ◽  
Bituminous Coal ◽  
Nox Reduction ◽  
Unburned Carbon ◽  
Gas Temperature ◽  
Mean Particle Size ◽  
High Volatility ◽  
Order Of Magnitude ◽  
Char Reactivity ◽  
Computational Fluid Dynamics Cfd

Biomass reburn is a low NOx alternative to cofiring that effectively uses the high volatility and high char reactivity of biomass for NOx reduction. In this paper, computational fluid dynamics (CFD) and thermal modeling, and a NOx prediction model were used to evaluate the impacts of sawdust/coal reburn on the performance of a 250 MW opposed-fired boiler burning bituminous coal as the primary fuel. The results showed that the reburn system maintained overall boiler performance with a 50 – 70 °F reduction in the furnace exit gas temperature. Predicted losses in thermal efficiency were caused by the lower biomass fuel heating value (similar to biomass cofiring) and increase in unburned carbon. The higher unburned carbon emissions were attributed to an order of magnitude larger biomass mean particle size relative to bituminous coal. Thus, LOI emissions can be improved significantly by reducing the biomass mean particle size. The NOx predictions showed that for reburn rates above about 19%, adding dry sawdust biomass to a coal reburn system can improve NOx reduction; i.e., using pure dry sawdust as reburn fuel at 30% of the total heat input can lead to NOx levels about 30% less than those for pure coal reburn under for similar firing conditions.

The Study of Surface Roughness and MRR of Mild Steel Using Manual Plasma Arc Cutting Machining

2012 ◽  
Vol 576 ◽  
pp. 3-6 ◽  
Author(s):  
R. Bhuvenesh ◽  
M.S. Abdul Manan ◽  
M.H. Norizaman
Keyword(s):  
Surface Roughness ◽  
Removal Rate ◽  
Cutting Process ◽  
Material Surface ◽  
Plasma Arc ◽  
Manufacturing Companies ◽  
Average Roughness ◽  
Plasma Arc Cutting ◽  
Before And After ◽  
Manual Plasma

Manufacturing companies define the qualities of thermal removing process based on the dimension and physical appearance of the cutting material surface. Therefore, the roughness of the surface area of the cutting material and the rate of the material being removed during the manual plasma arc cutting process was importantly considered. Plasma arc cutter Selco Genesis 90 was used to cut the specimens made from Standard AISI 1017 Steel manually based on the selected parameters setting. Two different thicknesses of specimens with 3mm and 6mm were used. The material removal rate (MRR) was measured by determining the weight of the specimens before and after the cutting process. The surface roughness (SR) analysis was conducted to determine the average roughness (Ra) value. Taguchi method was utilized as an experimental layout to obtain MRR and Ra values. The results reveal that for the case of manual plasma arc cutting machining, the SR values are inversely proportional to the MRR values. The quality of the surface roughness depends on the dross peak that occurred during the cutting process.

Influence of dissolved oxygen concentration on the start-up of the anammox-based process: ELAN®

2015 ◽  
Vol 72 (4) ◽  
pp. 520-527 ◽  
Author(s):  
N. Morales ◽  
A. Val del Río ◽  
J. R. Vázquez-Padín ◽  
R. Gutiérrez ◽  
R. Fernández-González ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Removal Rate ◽  
Batch Reactor ◽  
Thick Layer ◽  
Average Diameter ◽  
Bulk Liquid ◽  
Anammox Bacteria ◽  
Total Biomass ◽  
Ammonia Oxidizing Bacteria ◽  
Anaerobic Digester Supernatant

The anammox-based process ELAN® was started-up in two different sequencing batch reactor (SBR) pilot plant reactors treating municipal anaerobic digester supernatant. The main difference in the operation of both reactors was the dissolved oxygen (DO) concentration in the bulk liquid. SBR-1 was started at a DO value of 0.4 mg O2/L whereas SBR-2 was started at DO values of 3.0 mg O2/L. Despite both reactors working at a nitrogen removal rate of around 0.6 g N/(L d), in SBR-1, granules represented only a small fraction of the total biomass and reached a diameter of 1.1 mm after 7 months of operation, while in SBR-2 the biomass was mainly composed of granules with an average diameter of 3.2 mm after the same operational period. Oxygen microelectrode profiling revealed that granules from SBR-2 where only fully penetrated by oxygen with DO concentrations of 8 mg O2/L while granules from SBR-1 were already oxygen penetrated at DO concentrations of 1 mg O2/L. In this way granules from SBR-2 performed better due to the thick layer of ammonia oxidizing bacteria, which accounted for up to 20% of all the microbial populations, which protected the anammox bacteria from non-suitable liquid media conditions.

Study on the Preparation of Ceramic Membrane and the Treatment of Tanning Wastewater

2012 ◽  
Vol 487 ◽  
pp. 903-907 ◽  
Author(s):  
Jian Gen Wang ◽  
Ya Hui Liu
Keyword(s):  
Ceramic Membrane ◽  
Removal Rate ◽  
Ammonia Nitrogen ◽  
Sintering Process ◽  
Before And After ◽  
Tanning Process ◽  
Sulfide Content ◽  
Removal Efficiencies ◽  
Process Wastewater ◽  
Plate Type

Preparing 0.2μm, 3μm and 10μm three types of ceramic membrane with membranes pore size through solid state ion sintering process, and treat tanning process wastewater by them. Analyze hardness, sulfide content, ammonia nitrogen (NH3-N) and CODCr before and after the wastewater treatment, calculate and compare their removal rates. Results indicated that tanning process wastewater was treat by plate-type ceramic membrane, the removal rate of wastewater hardness was over 63%, the removal rate of sulfide, CODCr and NH3-N could be achieved 83%. It can get satisfactory removal efficiencies, and meet the national discharge standard, also can be recycled in industry.

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