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.

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.

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.

scholarly journals Analysis Combustion Efficiency in a Fluidized-Bed Combustor With a Modified Perforated Plate for Air Distribution

2021 ◽  
Author(s):  
Erdiwansyah Erdiwansyah ◽  
Mahidin Mahidin ◽  
Husni Husin ◽  
Nasaruddin Nasaruddin ◽  
Muhtadin Muhtadin ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Combustion Temperature ◽  
Perforated Plate ◽  
Combustion Efficiency ◽  
Biomass Waste ◽  
Transfer Rates ◽  
Burn Out ◽  
Maximum Combustion Temperature ◽  
Solid Biomass ◽  
Fluidized Bed Combustor

Abstract Combustion efficiency is one of the most important parameters, especially in the FBC combustion chamber. Investigations into the efficiency of combustion in FBC fuels using solid biomass waste fuels in recent years are increasingly in demand by researchers around the world. Specifically, this study aims to calculate the combustion efficiency in the FBC combustion chamber. Combustion efficiency is calculated based on combustion results from modification of hollow plates in the FBC combustion chamber. The modified hollow plate aims to control combustion so that the fuel incorporated can burn out and not saturate. The combustion experiments were tested using palm oil biomass solid waste fuels such as PKS, OPM, and EFB. The results of the measurements showed that the maximum combustion temperature for MCC fuel reached 863oC for M1 and 887oC on M2. The maximum combustion temperature measurements for M1 and M2 from OPM fuel testing reached 898oC and 858oC, respectively, while the maximum combustion temperature for EFB fuel was 667oC andM2 847oC, respectively. The rate of combustion efficiency with the modification of the hole plate in the FBC combustion chamber reached 96.2%. Thermal efficiency in FBC combustion chamber for OPM 72.62%, MCC 70.03%, and EFB 52.43%. The highest heat transfer rates for OPM fuel reached 7792.36 w/m, MCC 7167.38 w/m, and EFB 5127.83 w/m. Thus, modification of the holed plate in the FBC chamber showed better performance of the plate without modification.

scholarly journals Analysis Combustion Efficiency in a Fluidized-Bed Combustor With a Modified Perforated Plate for Air Distribution

2021 ◽  
Author(s):  
Erdiwansyah Erdiwansyah ◽  
Mahidin Mahidin ◽  
Husni Husin ◽  
Nasaruddin Nasaruddin ◽  
Muhtadin Muhtadin ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Combustion Temperature ◽  
Perforated Plate ◽  
Combustion Efficiency ◽  
Biomass Waste ◽  
Transfer Rates ◽  
Burn Out ◽  
Maximum Combustion Temperature ◽  
Solid Biomass ◽  
Fluidized Bed Combustor

Abstract Combustion efficiency is one of the most important parameters, especially in the FBC combustion chamber. Investigations into the efficiency of combustion in FBC fuels using solid biomass waste fuels in recent years are increasingly in demand by researchers around the world. Specifically, this study aims to calculate the combustion efficiency in the FBC combustion chamber. Combustion efficiency is calculated based on combustion results from modification of hollow plates in the FBC combustion chamber. The modified hollow plate aims to control combustion so that the fuel incorporated can burn out and not saturate. The combustion experiments were tested using palm oil biomass solid waste fuels such as PKS, OPM, and EFB. The results of the measurements showed that the maximum combustion temperature for MCC fuel reached 863oC for M1 and 887oC on M2. The maximum combustion temperature measurements for M1 and M2 from OPM fuel testing reached 898oC and 858oC, respectively, while the maximum combustion temperature for EFB fuel was 667oC andM2 847oC, respectively. The rate of combustion efficiency with the modification of the hole plate in the FBC combustion chamber reached 96.2%. Thermal efficiency in FBC combustion chamber for OPM 72.62%, MCC 70.03%, and EFB 52.43%. The highest heat transfer rates for OPM fuel reached 7792.36 w/m, MCC 7167.38 w/m, and EFB 5127.83 w/m. Thus, modification of the holed plate in the FBC chamber showed better performance of the plate without modification.

Optimization Process of Biomass Combustion in the Advanced FBC Using Factorial Design and Response Surface Methodology

2005 ◽  
Author(s):  
Shijun Zhu ◽  
Yun Liu ◽  
Seong Lee
Keyword(s):  
Response Surface Methodology ◽  
Moisture Content ◽  
Factorial Design ◽  
Poultry Manure ◽  
Combustion Efficiency ◽  
Air Injection ◽  
Excess Air ◽  
Secondary Air Injection ◽  
Carbon Combustion ◽  
Secondary Air

This paper studied the optimization process of the combustion of poultry waste material (i.e. poultry manure) in an advanced fluidized bed combustor (FBC) with the secondary air tangential injection. In order to test the influences of combustion parameters on the carbon combustion efficiency, factorial design (FD) and response surface methodology (RSM) were applied in the experimental process and data analysis. The parameters studied were moisture content, waste/natural gas ratio, excess air ratio, secondary/total air ratio, and the height levels of the secondary air injection. Using the 25−1 fractional factorial design, moisture content, excess air and secondary air injection height were found to be significant for the carbon combustion efficiency at the critical level of type-I error α = 0.1. The RSM was used to approach the optimal combustion condition. The optimal condition regarding the significant factors was found. Then the data from a validation experiment was compared with the computed combustion efficiency under the optimal condition. The result showed the combustion efficiency for poultry manure can reach up to 83%, which indicated that the poultry manure could be effectively burned in the advanced FBC.

scholarly journals Modeling of the Thermal Efficiency of a Whole Cement Clinker Calcination System and Its Application on a 5000 MT/D Production Line

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5257
Author(s):  
Yanfei Yao ◽  
Songxiong Ding ◽  
Yanxin Chen
Keyword(s):  
Calcium Carbonate ◽  
Thermal Efficiency ◽  
Production Line ◽  
Cement Clinker ◽  
Specific Process ◽  
Excess Air ◽  
Positive Linear Correlation ◽  
Excess Air Coefficient ◽  
Secondary Air ◽  
The Relationship

This paper proposes that the scope of research should be extended to the whole clinker calcination system from its single device or specific process (i.e., its functional subunits) as conventionally conducted. Mass/heat flow and effective heat were first analyzed to obtain the thermal efficiencies of its subunits (φi); a thermal efficiency model of the whole system φQY was thus established by correlating the relationship between φi and φQY. The thermal efficiency model of the whole system showed that φi had a positive linear correlation with φQY; it was found that the thermal efficiency of the decomposition and clinker calcination unit (φDC) had the greatest weight on φQY, where a 1% increase in φDC led to a 1.73% increase in φQY—improving φDC was shown to be the most effective way to improve φQY. In this paper, the developed thermal efficiency model was applied to one 5000 MT/D production line. It was found that its φQY was only 61.70%—about 2.35% lower than a representative line; such decrease was caused by its low φDC and φP which, as disclosed by model, were derived from the low decomposition rate of calcium carbonate in preheated meal put into a calciner and the high excess air coefficient of secondary air. Controlled parameter optimization of this 5000 MT/D production line was then carried out. As a result, the φDC and φP of the production line were increased from 30.03% and 64.61% to 30.69% and 65.69%, respectively; the φQY increased from 61.70% to 62.55%; the clinker output of the production line increased from 5799 MT/D to 5968 MT/D; the heat consumption of clinker was reduced from 3286.98 kJ/kg·cl to 3252.41 kJ/kg·cl.

The Influence of Excess Air Coefficient of Boiler Efficiency

2013 ◽  
Vol 409-410 ◽  
pp. 548-552
Author(s):  
Jiu Sheng Shi ◽  
Fei Peng ◽  
Bing Wen Zhang
Keyword(s):  
Thermal Efficiency ◽  
Linear Relation ◽  
Combustion Efficiency ◽  
Efficiency Analysis ◽  
Furnace Temperature ◽  
Excess Air ◽  
Important Impact ◽  
Boiler Efficiency ◽  
Excess Air Coefficient ◽  
One To One

Excess air coefficient has an important impact on the combustion conditions of boiler and thermal efficiency, analysis shows that the furnace temperature and the combustion efficiency is the linear relation of one to one correspondence. Any combustion conditions, there is an optimum excess air coefficient makes the top of furnace temperature, thus it can establish a control relationship, furnace temperature is optimization index, excess air coefficient is disturbance.It can achieve the purpose of improving the efficiency of boiler combustion.

scholarly journals Universal Combustion Chamber for Utilization of Petroleum Gases of Different Composition and Heat Output

2021 ◽  
Author(s):  
Alena Shilova ◽  
◽  
Nikolai Bachev ◽  
Oleg Matyunin ◽  
◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Power Plants ◽  
Energy Balance Equation ◽  
Working Fluid ◽  
Heat Output ◽  
Combustion Chambers ◽  
Fuel Gas ◽  
Excess Air ◽  
Secondary Air

When developing micro-gas turbine power plants, it is necessary to have universal two-zone combustion chambers for utilizing petroleum gases of different composition and heat output at different oil deposits. In the combustion zone, the excess air ratio is selected from the interval between the lower and upper concentration limits of combustion. In the dilution zone by supplying secondary air, the working fluid with specified parameters is prepared for supply to the turbine. The excess air coefficient at the exit from the combustion chamber is determined from the energy balance equation and depends on the air and fuel gas parameters at the entrance to the combustion chamber and on the temperature of the working fluid at the entrance to the turbine. The purpose of this work is to develop recommendations for creating a universal combustion chamber for combustion of fuel gases of different composition and heat output. This goal is achieved by selecting the diameter of the chamber in order to ensure the required ratios between the average flow rate of the combustible air mixture and the rate of turbulent combustion, at which a stable position of the flame front is observed. The most noticeable result of the research conducted is substantiation of the possibility of using a universal combustion chamber with constant dimensions in utilization gas turbine installations designed for burning nonstandard fuel gases with ballasting components content up to 70%, which will reduce the time and cost of development and implementation of these installations.

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