Experimental Study on Combustion Characteristic of Biomass Micron Fuel

2017 ◽  
Author(s):  
Qi Zhang ◽  
Bo Xiao ◽  
Shiping Jin ◽  
Xun Wang ◽  
Xiaokang Liu ◽  
...  
Keyword(s):  
Particle Size ◽  
Combustion Temperature ◽  
Combustion Characteristic ◽  
Agriculture Waste ◽  
Fuel Feed ◽  
Fuel Ratio ◽  
Excess Air ◽  
Waste Energy ◽  
Excess Air Coefficient ◽  
Forestry Residues

This study developed a new kind of biomass fuel with biomass (forestry residues, agriculture waste, energy crops and so on) crushed below certain particle size (micron level, ≤250 μm) to form biomass powder, biomass-micron-fuel (BMF). And effects of excess air coefficient, air-fuel ratio, and particle size of BMF on the combustion temperature were studied through a self-designed lab-scale cyclone combustion system. Results showed that temperature increased first and then decreased with the increasing air flow rate and best excess air coefficient occurred in the region of 1.05–1.18. Similarly, combustion temperature also increased first and then decreased as the fuel feed rate increased and 225 g/m3–265 g/m3 air-fuel ratio would guarantee the effective combustion of BMF. The influence of particle size on the combustion temperature was also determined under five different combustion conditions and results demonstrated that the smaller the particle size is, the higher the temperature will be. (CSPE)

Modeling and Experiment on Combustion Characteristics for Biomass Rotary Burner

2020 ◽  
Vol 04 ◽  
Author(s):  
Guohai Jia ◽  
Lijun Li ◽  
Li Dai ◽  
Zicheng Gao ◽  
Jiping Li
Keyword(s):  
Combustion Chamber ◽  
Combustion Temperature ◽  
Combustion Efficiency ◽  
Middle Part ◽  
Combustion Characteristics ◽  
Maximum Temperature ◽  
Excess Air ◽  
Element Simulation ◽  
Excess Air Coefficient ◽  
Secondary Air

Background: A biomass pellet rotary burner was chosen as the research object in order to study the influence of excess air coefficient on the combustion efficiency. The finite element simulation model of biomass rotary burner was established. Methods: The computational fluid dynamics software was applied to simulate the combustion characteristics of biomass rotary burner in steady condition and the effects of excess air ratio on pressure field, velocity field and temperature field was analyzed. Results: The results show that the flow velocity inside the burner gradually increases with the increase of inlet velocity and the maximum combustion temperature is also appeared in the middle part of the combustion chamber. Conclusion: When the excess air coefficient is 1.0 with the secondary air outlet velocity of 4.16 m/s, the maximum temperature of the rotary combustion chamber is 2730K with the secondary air outlet velocity of 6.66 m/s. When the excess air ratio is 1.6, the maximum temperature of the rotary combustion chamber is 2410K. When the air ratio is 2.4, the maximum temperature of the rotary combustion chamber is 2340K with the secondary air outlet velocity of 9.99 m/s. The best excess air coefficient is 1.0. The experimental value of combustion temperature of biomass rotary burner is in good agreement with the simulation results.

scholarly journals Effect Analysis on Combustion and Emission Characteristics of a Rotary Burner Fueled by Biomass Pellet Fuel

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Guohai Jia ◽  
Lijun Li ◽  
D. M. Zhang
Keyword(s):  
Gas Flow ◽  
Combustion Temperature ◽  
Concentration Field ◽  
Large Temperature ◽  
Middle Region ◽  
Steady State Condition ◽  
Excess Air ◽  
Excess Air Coefficient ◽  
Simulation Results ◽  
Biomass Pellet

A biomass pellet rotary burner was chosen as the research object, in order to study the influence of excess air coefficient on the combustion phenomenon of biomass rotary burner, the finite element simulation model of a biomass rotary burner was established, and simulation results of a biomass rotary burner were verified by the experiment. The computational fluid dynamics software was applied to simulate the combustion characteristics of biomass rotary burner in a steady-state condition, and the effect of excess air coefficient on temperature field and component concentration field in biomass rotary burner was analyzed. The results show that the flue gas flow rate inside the burner gradually increases with the increase of air velocity, the area with large temperature is mainly concentrated in the middle region of the rotary burner, and the maximum combustion temperature also appeared in the middle region of the combustion chamber, and the formation area of CO decreases with the increase of excess air coefficient. CO2 is mainly concentrated in the middle region of the burner, and the CO2 generating region decreases with the increase of excess air coefficient. The experimental value of the combustion temperature of the biomass rotary burner is in good agreement with the simulation results.

Research on the Burnout of Fujian Anthracite in CFB Boiler

2011 ◽  
Author(s):  
H. Z. He ◽  
H. H. Zhuang ◽  
Z. Y. Luo ◽  
K. F. Cen
Keyword(s):  
Fly Ash ◽  
Combustion Temperature ◽  
Separation Efficiency ◽  
Operating Parameter ◽  
Cfb Boiler ◽  
Excess Air ◽  
Circulation Ratio ◽  
Excess Air Coefficient ◽  
Secondary Air ◽  
Combustion Reactivity

Coal property, boiler structural and designing parameters, running parameters of boiler are the main factors which influence the burnout of Fujian anthracite during combustion in CFB boiler. These coal properties and combustion characteristics such as the compact inner structure of particle, the poor combustion reactivity, and the strong thermal fragmentation tendency are the main reason that cause the Fujian anthracite difficult to burnout in CFB boiler. And these operating parameter such as the combustion temperature, the particle size distribution of feeding coal, the flow velocity of flue gas in furnace, the fly ash reburning, the excess air coefficient and the secondary air ratio have also an strong effect on its burnout. By means of improving the boiler structure and designing parameter such as rising the height of furnace, layout of refractory belt, choosing low-medium circulation ratio, employing high separation efficiency cyclone, ect, can also promote the burnout of Fujian anthracite when it combustion in CFB boiler. For those small-medium capacity CFB boiler (capacity ≤ 75 t/h) burning Fujian anthracite, due to its limited height of furnace, it is good to improve the burnout of Fujian anthracite by adjusting the operation parameter of boiler such as employing the mid-coarse size particle in feeding coal, properly rising the excess air coefficient and the secondary air ratio, intensifying the perturbation and penetration capability of secondary air in furnace, increasing the combustion temperature, and reburning the fly ash. In order to get a good burnout result, the running temperature of boiler should be risen to about 1000 °C, and the excess air coefficient is supposed to maintain in 1.25–1.30.

scholarly journals A Thermally Conductive Pt/AAO Catalyst for Hydrogen Passive Autocatalytic Recombination

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 491
Author(s):  
Alina E. Kozhukhova ◽  
Stephanus P. du Preez ◽  
Aleksander A. Malakhov ◽  
Dmitri G. Bessarabov
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Combustion Temperature ◽  
Volume Fraction ◽  
Morphological Characteristics ◽  
Al Alloy ◽  
Impregnation Method ◽  
Case Scenario ◽  
Worst Case ◽  
Thermal Distribution

In this study, a Pt/anodized aluminum oxide (AAO) catalyst was prepared by the anodization of an Al alloy (Al6082, 97.5% Al), followed by the incorporation of Pt via an incipient wet impregnation method. Then, the Pt/AAO catalyst was evaluated for autocatalytic hydrogen recombination. The Pt/AAO catalyst’s morphological characteristics were determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The average Pt particle size was determined to be 3.0 ± 0.6 nm. This Pt/AAO catalyst was tested for the combustion of lean hydrogen (0.5–4 vol% H2 in the air) in a recombiner section testing station. The thermal distribution throughout the catalytic surface was investigated at 3 vol% hydrogen (H2) using an infrared camera. The Al/AAO system had a high thermal conductivity, which prevents the formation of hotspots (areas where localized surface temperature is higher than an average temperature across the entire catalyst surface). In turn, the Pt stability was enhanced during catalytic hydrogen combustion (CHC). A temperature gradient over 70 mm of the Pt/AAO catalyst was 23 °C and 42 °C for catalysts with uniform and nonuniform (worst-case scenario) Pt distributions. The commercial computational fluid dynamics (CFD) code STAR-CCM+ was used to compare the experimentally observed and numerically simulated thermal distribution of the Pt/AAO catalyst. The effect of the initial H2 volume fraction on the combustion temperature and conversion of H2 was investigated. The activation energy for CHC on the Pt/AAO catalyst was 19.2 kJ/mol. Prolonged CHC was performed to assess the durability (reactive metal stability and catalytic activity) of the Pt/AAO catalyst. A stable combustion temperature of 162.8 ± 8.0 °C was maintained over 530 h of CHC. To confirm that Pt aggregation was avoided, the Pt particle size and distribution were determined by TEM before and after prolonged CHC.

Effect of thermal input, excess air coefficient and combustion mode on natural gas MILD combustion in industrial-scale furnace

Fuel ◽  
2021 ◽  
Vol 302 ◽  
pp. 121179
Author(s):  
Mingming Huang ◽  
Ruichuan Li ◽  
Jikang Xu ◽  
Shen Cheng ◽  
Haoxin Deng ◽  
...  
Keyword(s):  
Natural Gas ◽  
Industrial Scale ◽  
Combustion Mode ◽  
Mild Combustion ◽  
Excess Air ◽  
Excess Air Coefficient

The Effect of Biomass Shapes on Combustion Characteristic in Updraft Chamber

2021 ◽  
Vol 13 (4) ◽  
Author(s):  
Wasu Suksuwan ◽  
◽  
Mohd Faizal Mohideen Batcha ◽  
Arkom Palamanit ◽  
Makatar Wae-hayee ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Combustion Chamber ◽  
Combustion Temperature ◽  
Ambient Air ◽  
Combustion Characteristics ◽  
Flue Gases ◽  
Combustion Characteristic ◽  
Rubber Wood ◽  
Chip Shape ◽  
Biomass Sample

Combustion of agricultural residues and wastes for energy applications is still popular. However, combustion of biomass with different shapes leads to many side effects such as agglomeration, emission and incomplete combustion. The aim of this study was therefore to investigate the effects of biomass shapes on combustion characteristics in an updraft combustion chamber. The rubber wood chip, coconut shell, oil palm empty fruit bunch, corn straw, rubber wood sawdust, and mixed palm cake were used as fuel and they were categorized as 3 shapes namely, chip shape, fiber shape, and powder shape. The biomass sample was combusted in simple cylindrical shape combustion chamber. The diameter of combustion chamber was 20 cm and its height was 160 cm. The biomass sample (moisture content below 20%) with amount of 1 kg was used to perform the experiment. The ambient air that had velocity of 0.50, 0.75 and 1.00 m/s (corresponding to an equivalence ratio of 1-3.5) was supplied to combustion chamber. The temperature at different positions along combustion chamber height and the properties of flue gases (carbon monoxide) were then measured. The results showed that the biomass shape had effect on combustion characteristics. Combustion of fiber shape biomass led to low combustion temperature, while the carbon monoxide in flue gases was high. This indicates the improper combustion process. The chip shape biomass was well combusted at a higher air velocity and the flue gases had lowest carbon monoxide. The highest combustion temperature was obtained from combustion of powder shape biomass. However, it led to the problem of unburned biomass such in case of sawdust. This is because the sawdust powder was carried from combustion chamber before burning completely.

Effects of Air Flowrate on the Combustion and Emissions of Blended Corn Straw and Pinewood Wastes

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Xiaoxiao Meng ◽  
Wei Zhou ◽  
Emad Rokni ◽  
Honghua Zhao ◽  
Rui Sun ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ignition Delay Time ◽  
Fixed Bed ◽  
Combustion Efficiency ◽  
Fixed Bed Reactor ◽  
Corn Straw ◽  
Excess Air ◽  
Burning Rates ◽  
Excess Air Coefficient ◽  
Hazardous Pollutants

This research investigated the effects of the specific primary (under-fire) air flowrate (m˙air) on the combustion behavior of a 50–50 wt % blend of raw corn straw (CS) and raw pinewood wastes in a fixed-bed reactor. This parameter was varied in the range of 0.079–0.226 kg m−2 s−1, which changed the overall combustion stoichiometry from air-lean (excess air coefficient λ = 0.73) to air-rich (excess air coefficient λ = 1.25) and affected the combustion efficiency and stability as well as the emissions of hazardous pollutants. It was observed that by increasing m˙air, the ignition delay time first increased and then decreased, the average bed temperatures increased, both the average flame propagation rates and the fuel burning rates increased, and the combustion efficiencies also increased. The emissions of CO as well as those of cumulative gas phase nitrogen compounds increased, the latter mostly because of increasing HCN, while those of NO were rather constant. The emissions of HCl decreased but those of other chlorine-containing species increased. The effect of m˙air on the conversion of sulfur to SO2 was minor. By considering all of the aforesaid factors, a mildly overall air-rich (fuel-lean) (λ = 1.04) operating condition can be suggested for corn-straw/pinewood burning fixed-bed grate-fired reactors.

Numerically Study on Combustion and NOx Emission Characteristics in Tangentially Fired Boiler Co-Firing Semi-Coke

2018 ◽  
Author(s):  
Yongbo Du ◽  
Chang'an Wang ◽  
Pengqian Wang ◽  
Qiang Lv ◽  
Defu Che
Keyword(s):  
Bituminous Coal ◽  
Combustion Efficiency ◽  
Low Rank ◽  
Operation Performance ◽  
Combustion Heat ◽  
Practical Utilization ◽  
Excess Air ◽  
Utility Boilers ◽  
Excess Air Coefficient ◽  
Char Burnout

Semi-coke is a specific solid fuel, which is mainly produced by upgrading low-rank coal. The poor reactivity of semi-coke makes a difficulty to its practical utilization in utility boilers. Previous research was mainly focused on the combustion behavior of semi-coke, while the industrial application has to be understood. In this paper, the effect of co-firing semi-coke and bituminous coal on the operation performance of pulverized boiler was numerically studied. The work was conducted on a 300 MW tangentially fired boiler, and the temperature distribution, the char burnout and NOx production were mainly examined. The results indicate that the incomplete combustion heat loss drops with the increase in semi-coke blending ratio. The NOx concentration increases from 186 mg/Nm3 for only firing the bituminous coal to 200, 214, and 255 mg/Nm3, when the blending ratio was 17%, 33% and 50%, respectively. With enhancing excess air coefficient for the co-firing condition, the combustion efficiency got improved, while NOx production increased very slightly. In general, the boiler is well adapted to co-firing semi-coke, and the semi-coke blending ratio of 1/3 with an excess air coefficient of 1.235 is recommended.

Experimental Study on Combustion Characteristics of Biomass and Coal Blended

2013 ◽  
Vol 805-806 ◽  
pp. 200-207
Author(s):  
Bing Zhang ◽  
Guang Wu Lu
Keyword(s):  
Particle Size ◽  
Ignition Temperature ◽  
Combustion Process ◽  
Combustion Characteristics ◽  
Combustion Characteristic ◽  
Thermogravimetric Analyzer ◽  
Rate Of Combustion ◽  
Mixing Proportion ◽  
Biomass Particle Size ◽  
Obvious Weight Loss

Under different conditions,combustion characteristics of the single biomass,the single coal and the mixture of biomass and coal were analyzed by using thermogravimetric analyzer. Combustion characteristic parameters of the sawdust,the rice husk,the rice straw and the Baisha coal of Leiyang were studied,including ignition temperature,the maximum rate of combustion temperature,the burnout temperature and so on. The experimental results show that the biomass burning temperature is lower than the Baisha coal and there are two obvious weight loss phases in the combustion process of the biomass. However,there is only one in the coal. The ignition temperature and time of the coal can be reduced ,the temperature range of the entire combustion can be extended,the coal can be burnout more well and the fuel combustion characteristic can be optimized by blending combustion. With the increase of biomass mixing proportion, the ignition temperature of mixing samples was decreased more obviously. Moreover,when the biomass particle size becomes R200,compared with R90 particle size under the same blending ratio,its ignition temperature is more lower.

Numerical Simulation on Moisture Influence to MSW Combustion

2014 ◽  
Vol 1006-1007 ◽  
pp. 181-184
Author(s):  
Zhu Sen Yang ◽  
Xing Hua Liu ◽  
Shu Chen
Keyword(s):  
Numerical Simulation ◽  
Moisture Content ◽  
Flue Gas ◽  
Combustion Process ◽  
Average Temperature ◽  
Excess Air ◽  
Heat Value ◽  
Moisture Influence ◽  
Excess Air Coefficient ◽  
Combustible Gases

The combustion process of municipal solid waste (MSW) in a operating 750t/d grate furnace in Guangzhou was researched by means of numerical simulation. The influence of MSW moisture content on burning effect was discussed. The results show that: with the moisture content dropped from 50% to 30%, the heat value could be evaluated from 13.72% to 54.91% and the average temperature in the furnace could be promoted 90-248°C. However, the combustible gases and particle in the flue gas of outlet would take up a high proportion since lacking of oxygen would lead to an incomplete combustion. The excess air coefficient should be increased to 2.043~2.593 in order to ensure the flue gas residence time more than 2s and temperature in the furnace higher to 800°C.

Sign in / Sign up

Export Citation Format

Share Document