Numerical Study of the Effect of Primary Air Velocity of Pulverizer...

International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:20 No:01 70

202101-5353-IJMME-IJENS © February 2020 IJENS I J E N S

Abstract— The challenges faced by the electricity industry

in Indonesia at present with a considerable generating

capacity. One of them is the problem of variations in coal

calories and fuel prices. Besides that, it also relates to the

amount of generating capacity which has an impact on the

amount of NOx gas release which has the potential to disturb

the environment. By understanding the mechanism of

optimization and setting of the pulverizer in this case the primary air velocity settings that coming out of each pulverizer

output line can improve the performance of the generator itself

and reduce NOx gas. By setting the primary air velocity at the

outlet the process of forming fireball is more perfect which

influences a better combustion process. Thus, the purpose of

this research is to obtain the condition of setting the primary

air velocity so that it causes the combustion process to produce

exhaust gas with NOx content that meets the applicable

criteria. In this study the Computational Fluid Dynamics (CFD)

method is used. The boiler geometries are made using Gambit

software and for numerical simulations using ANSYS Fluent

software 19.2. For validation, the initial simulation results for the current boiler conditions are compared with actual

measurement data. Furthermore, it will be simulated by

varying the primary air velocity. The simulation results show that the effect of increasing in

velocity outlet of pulverizer on the combustion temperature in

the furnace (without changing secondary water) is inversely

proportional. The greater the velocity outlet pulverizer, the

lower the combustion temperature in the furnace. So that the

recommended model design is a variation of the velocity outlet

of pulverizer with a speed of 28 m/s because it has a

superheater inlet temperature slightly above the existing

model, so that the use of superheater and reheat spray only

slightly adds to the existing model while for NOx mass fraction

boiler output is around 65% of the existing model.

Index Term— Primary air velocity, fireball, computational

Fluid Dynamic, Power Plant.

I. INTRODUCTION

In boilers, air and exhaust gases play an important role in

the combustion process. The air system in general is a

system that functions as a medium for transporting coal to

the boiler, adding oxygen to the combustion process and

making turbulence (secondary air). In this case, there needs

to be optimal air control so that the combustion process is

perfect and efficient. While, the exhaust gas system is the output of the combustion process which is used to transfer

the hot gas from the remaining combustion process to water

and steam pipes and air heating elements. At the time of

stoichiometric combustion, it is a process of mixing

chemical elements between air and fuel which produce

products H, SOx, NOx, CO2, etc. Therefore, it is necessary

to pay attention to how much chemical elements are

produced in the combustion process. In addition, to pay

attention to the balance of fuel and air, it is also necessary to

study the effects of flow imbalance from each angle of the

burner on the combustion product. Air flow regulation can improve the combustion balance

in the boiler. Oxygen, exhaust gas flow rate, temperature

and NOx imbalance at the boiler outlet can be significantly

reduced [1]. Flow velocity distribution at the burner in high

speed of NOx formation occurs in the center of the fire ball

and small when the flow velocity in the burner decreases

until it does not reach the center of fireball and forms NOx it

widens [2].

Good tangential circulation of gas causes an increase in

flame distribution [3]. When primary air from the burner is

injected into the furnace, in the center of the furnace will form a fireball in a clockwise direction. The secondary air

concentric firing is biased relative to the direction of the

primary air jet. Near the water wall, it will result a stronger

oxidizing atmosphere. This is to reduce the risk of slagging

and longer residence time for pulverized coal in the furnace,

to diminish the carbon content in the fly ash. However, a

larger tangential circle diameter is formed, which leads to a

dense residual rotation flow at the furnace exit and this will

produce in an increase in the temperature deviation of the

gas at the crossover pass [4].

According to the authors [5], there are three mecahnism

must be taken account in the modeling of NOx formation, such as: formation of thermal NOx, formation of prompt

NOx, and formation of fuel NOx. Temperature in the burner

zone and the resulting NOx emissions are closely related to

the type of fuel used. The air that is inserted into the boiler

can cool the exhaust gas so that the temperature and

concentration of the species drops as the ratio of excess air

[6]. Higher mixing rates from air and fuel tend to reduce

unburned combustibles at the expense of higher NOx

emissions [7]. The increase in the Primary air ratio has a

large influence on combustion performance. Overall, the

combustion process decreases with increasing Primary air ratio. However, in the main burner region and the area

above separated-over fire air (SOFA), the combustion characteristics show the trend of parabolic with the Primary

water ratio increasing [8]. The increase of the air flow rate

Numerical Study of the Effect of Primary Air

Velocity of Pulverizer Output on NOx

Formation in the Boiler of Labuan Steam Power

Plant, Indonesia Taufik Hidayat1, Triyogi Yuwono1, 2, *)

1Graduate Student in the Department of Mechanical Engineering, Institut Teknologi Sepuluh Nopember, 2Department of Mechanical Engineering, Institut Teknologi Sepuluh Nopember,

Jl. Arif Rahman Hakim, Kampus ITS-Sukolilo, Surabaya-60111, East Java, Indonesia *) Corresponding Author: [email protected]

mailto:[email protected]



leads as expected is a decrease of the furnace outlet temperature and an increase in NOx emissions [9]. When the difference in primary and secondary air flow velocity is large it can increase the combustion temperature but an increase in NOx emissions [10].

The suggested formula for NOx concentration was based

on three factors, i.e. moisture, fixed carbon, and fuel ratio

correlations. Having compared the calculated amount of

NOx generation from the actual power plant using four

system indicator factors (coefficients) while considering the

design and operating conditions of each boiler [11].

In accordance with the authors [12], the concentration of

NO augments fast in the furnace lowers part. In this zone,

volatile N reacts with O2 to form CNO that is in due course

oxidized to NO. Simultaneously, at the bottom of the

furnace, the combustion of charcoal particles forms NO. Compared with the observations of physical model, the

predictions through CFD model were generally better. The

CFD could precisely simulate the mixing and flow fields of

the boiler for a varied range of the inlet flow rate, however

some difference were also found for some flow conditions.

Primary air ratio has high impacts on the temperature and

atmosphere of combustion inside the furnace. Because, the

characteristics of NOx formation are mainly dependent on

the temperature of combustion and the oxidation/reduction

atmosphere inside the furnace [14].

II. RESEARCH METHODOLOGY

a. Simulation

This research includes 3 steps; the first step is taking

operational data as a basis for reference, including

operational data taken through Distribute Control System

(DCS), and laboratory data. The next step is to create a 3D

Boiler model base on real geometry of boiler with Gambit

Software, and the last is to validate the simulating model

and running several operating patterns with Computational

fluid dynamics (CFD) to get optimum results.

In this simulation data is taken from Labuan’s Power

Plant with 300 MW capacities of sub-critical specifications,

natural circulation, single furnace, tangential firing and, single reheat and balance draft [15].

This 3D Boiler model has 757724 nodes with shape of

the mesh are hexahedral and tetrahedral as shown in Fig. 1.

There are 5 coal burner elevation layers, 7 secondary air

dampers and 1 layer separated-over fire air (SOFA).

Operating data is obtained from the parameters in the

Distribute Control System (DCS), manual book and

laboratory data for coal properties. In this simulation we use

2 types of coal that is Low rank coal (LRC) for burner A and

burner B while burner C and E using medium rank coal

(MRC). Table 1 shows the properties of the coal, it is consist of ultimate and proximate analysis that needed for

input in simulation. While the other input data are:

a) Primary air Flow (kg/s).

b) Secondary Air Flow (kg/s).

c) Coal Flow (kg/s).

d) Boiler Outlet Pressure (Pa).

e) Heat exchanger (W/m3).

Fig. 1. Meshing boiler geometry models.



Table I.

Properties of coal

Heating Value Unit

AR

LRC MRC

Higher Heating Value (AR) kcal/kg-f 3,999 4,582

Higher Heating Value (AR) kJ/kg-f 16,744 19,183

Ultimate Analysis

Carbon Content (AR) wt % 43 58

Hydrogen Content (AR) wt % 3 6

Oxygen Content (AR) wt % 13 27

Sulfur Content (AR) wt % 0 1

Nitrogen Content (AR) wt % 1 1

Ash Content (AR) wt % 9 7

Moisture Content (AR) wt % 30 -

Total wt % 100 100

ProximateAnalysis

Total Moisture Content (AR) wt % 30 -

Fixed Carbon Content (AR) wt % 29 39

Volatile Matter (AR) wt % 32 38

Ash Content (AR) wt % 9 7

Total wt % 100 84

Carbon Content in Fly Ash wt % 2 2

Carbon Content in Bottom Ash wt % 2 2

Fly Ash Split wt % 1 1

Bottom Ash Split wt % 0 0

Mass of Residue wt % 0 0

Carbon in Ash wt % 2 2

Unburn Carbon in Fuel wt % 0 0

Carbon Burned Content wt % 43 58

Fig. 2. Boundary conditions and sensor location.



Fig. 3. Comparison between results of measurement and simulation – for validation.

Table II

Comparison data between results of measurement and simulation

Sensor Positions 1 2 3 4 5 6

Measured Results (0C) 971 889 800 660 654 401

Simulation Results (0C) 950 859 853 676 636 438

Error 2.20% 3.40% 6.60% 2.40% 2.80% 9.20%

Boundary conditions in this simulation, it can be classified

into 4 types, which are wall, mass flow inlet, pressure outlet

and interior. Fig. 2 describe inlet is primary air, coal flow

and secondary air is used boundary condition mass-flow-

inlet, while the boiler outlet uses a pressure outlet. Primary

air enters the furnace through burners A, B, C, D and E, but

in this simulation the D burner is standby so that the D

burner can be defined as a wall. Secondary air enters the

furnace through burners AA, AB, BC, CC, DD, DE, EF, and

EFF whereas the water wall tube becomes a boundary condition of the wall type by entering the temperature value

which is assumed to be the temperature of the water flowing

in the tube. Heat exchanger described as porous media with

its own heat absorption.

b. Validation

Before proceeding with the simulation at the various case

stages it is necessary to validate the simulation data. In this

study validation of the flue gas temperature between the

actual data is compared with the simulation data.

Fig. 3 indicates the comparison of the actual operating data

of the point of the flue gas temperature. Retrieval of data for

validation by making iso-points, in accordance with the

points, where the sensor is placed in the boiler sensor. Table

2 shows the measurement and simulation results. The results

showed that the simulation accuracy was assessed from the

error value between the actual (measured) data and the

simulation data less than 10%, with an average error value

of 4.43%. So, the simulation method used in this study can

be considered an accurate simulation and can be used to simulate the problem studied.

c. Simulation with alternative design

In this variation of simulation all parameters are made the

same as validation data except velocity Primary air outlet

data. Variations in velocity Primary air outlet affect the Primary air mass flow needed. The Table 3 mass flow data

obtained from several velocity Primary air outlets.

0

200

400

600

800

1000

1200

1 2 3 4 5 6

Tem

peratu

re (

oC

)

Sensor position

Measured results

Simulation results



Table III

Variation of simulation model

Velocity (m/s) PA per layer (T/h) Total PA (T/h) SA Flow (T/h) Total Air Flow (T/h) Coal Flow (T/h)

23 27.5 109.9 643.4 753.3 165.4

24 35.4 141.7 643.4 785.1 165.4

26 51.4 205.4 643.4 848.8 165.4

28 67.3 269.1 643.4 912.5 165.4

30 83.2 332.8 643.4 976.2 165.4

32 99.1 396.5 643.4 1,039.9 165.4

III. RESULTS AND DISCUSSION

To analyze the effect of variations in primary air flow

velocity on boiler that affects combustion process, so it is

necessary to analyze the contours of the magnitude of flow velocity on the boiler. Simulation results of the velocity

magnitude in the boiler as shown in Fig. 4.

Inside the boiler, the combustion process of particles of

coal and air produces flue gas with high temperature having

the direction of flue gas flowing from the furnace to the boiler outlet.

Fig. 4. Velocity Magnitude.

In the furnace, the air flow and coal particles coming out of

the four corners of the boiler burner and secondary water will form a fireball, with the fireball the trajectory of coal

particles becoming longer, which causes the time span of

particles in the furnace area will be longer. Another thing the effect of pressure area at the center of the furnace occurs



small due to in simulations 23 and 24 the low flue gas

velocity is in the lowest area of the boiler (bottom ash) due to

the lack of air flow, causing a portion of the coal particle on

burner A to go downward. In the middle part of the furnace a

low pressure is caused by the fireball effect. In simulations

23 and 24, taking vector velocity magnitude is done by

making a vertical cross section of the boiler. The velocity

magnitude vector results are shown in Fig. 4, the range of

velocity of coal varies between 0-23.5 m/s for all variations. In simulations 23 and 24 the low velocity primary air outlet

which indicates that the fireball that occurs at the center of

the furnace is only small and only reaches the super heater

inlet which is reduced due to constriction at the super heater

inlet. In the burner wall area, there is a low-pressure spot that

occurs in the burner area that is not standby.

Whereas, the low pressure outlets of the boiler are caused by

reduced flue gas velocity, after passing through the super

heater, reheat, and economizer panels. In simulation 26, the

pressure in the middle of the furnace which has a low

pressure widens due to the formation of an enlarged fireball

because the direction of coal flow in each corner affects each

other away from the midpoint of the furnace. The greater the

velocity primary air outlet the wider or larger approaching

the wall of the water wall. In simulation 28, 30 and 32, the

formation of fireball enlarges near the wall and is formed to

the bottom ash area to the super heater area.

The highest temperature occurs in the furnace area because

in this area the combustion process travels to the boiler outlet, the temperature decreases more and more due to

absorption in the water wall, super heater, reheat and

economizer. In Fig. 5, it is shown that the temperature

measurement range is between 0 oC to 1210 oC with a cross

section on the boiler, with the low velocity furnace

temperature produced higher when compared with higher

velocity.

Fig. 5. Static temperature cross section of the boiler.



Fig. 6. Distribution of profile temperature along furnace height.

Fig. 7. The pattern of fireball formation in velocity variations.

Fig. 6 demonstrates the combustion temperature at the

related elevation; where 7 m-elevation is the elevation at the

bottom ash while at the 47-m elevation is the super heater

inlet elevation. At variations 23, 24, and 26 the outlet furnace

temperature is high because the ratio of air and fuel is very

lame, i.e.; 1: 4.6-5.3, so that makes burning very rich which

causes very high temperatures, whereas the ratio of primary

air and secondary air is 1: 5.8 - 3.2. As for variations of 28,

7

12

17

22

27

32

37

42

47

52

200 400 600 800 1000 1200 1400 1600

Ele

vati

on

(m

)

Static Temperature (°C)

23 m/s

24 m/s

26 m/s

28 m/s

30 m/s

32 m/s



30 and 32, the ratio of air and fuel is 1: 5.5 - 6.3 which is

close to ideal combustion, but the ratio of primary air and

secondary air is 1: 2.3 - 1.6. This causes the combustion

temperature to decrease due to primary air temperature is

52.5 oC while secondary air is 324.4 oC. Theoretically, the

ratio between primary and secondary air for a 300 MW plant

is 1: 2.8 [7]. In addition to coal calories which greatly affect

the combustion results, it is also important to consider the

velocity outlet which serves to determine the location of the combustion process. The transverse contour area of each

burner and inlet super heater elevation in Fig. 7 can explain

the effect of fireball pattern formation on the velocity

primary air outlet.

It is noticed that the effect of the velocity of primary air

outlet on the combustion temperature is inversely

proportional to the temperature of combustion. For the effect

of fireball pattern formation on the velocity of the primary air

outlet, it is seen that the effect of the velocity primary air

outlet on the combustion temperature is inversely

proportional to the temperature of combustion. for the case of

variations of 24 m/s and 28 m/s in the bottom ash area, NO

concentrations can increase rapidly. Char particles are not

formed but volatile N reacts with the change of O2 to NO

which is then oxidized to NOx. So that the NOx mass

fraction in that area increases in that area [12]. In Fig. 8 can

be seen in burner A at a variation of 24 m/s high output

temperature so that thermal NOx can be created. Whereas in

the bottom ash, the largest NOx formation occurs due to organic nitrogen which is chemically bound in coal. The

reaction of NOx formation on the char surface is described in

the formula below:

C_Char+1/2 O_2↔〖CO〗_Char

N_Char+1/2 O_2↔NO+Char

NO+2〖CO〗_Char↔N_2+2〖CO〗_2+Char

Fig. 8. NOx Mass contour on cross section of boiler.



0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

1 2 3 4 5 623 m/s 24 m/s 26 m/s 28 m/s 30 m/s 32 m/s

Fig. 9. Mass fraction of NOx along furnace height.

Fig. 10. Mass fraction of NOx at outlet boiler.

The formula shows that the amount of NOx produced by nitrogen in coal increases with increasing residence time of

the burned particles. This relation can be observed as long as

the reaction occurs at temperatures above 800°C. The

increase in NOx due to nitrogen in the fuel can also occur

due to an increase in oxygen content in the flame which

results in a fuel poor condition [16], so that the mass fraction

of NOx is high in the bottom ash area.

At variations of 23 m/s, 24 m/s, 26 m/s and 28 m/s, thermal

NOx formation occurs with a high mass fraction because

around the burner area E temperature in the furnace section

reaches the requirement of thermal NOx formation of

1204oC. The asymmetry of NOx mass fraction formation in the area is due to the narrowing of the profile furnace when

entering the superheater inlet so that the fireball in the form

of fireball shifts to one side depending on the speed of the

primary air velocity. In variations of 30 m/s and 32 m/s in the

E burner area, NOx mass fraction formation also occurs but

this is small because the resulting temperature of combustion

is very low as in Fig. 8 above.

In case of variation 28 m/s, there is NOx formation in the

reheat area due to unburned coal in the furnace area and

oxidized area to form NOx.

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0.0014

0 10 20 30 40 50 60

Mass

Fracti

on

of

Poll

uta

n N

Ox

23 m/s 24 m/s

26 m/s 28 m/s

30 m/s 32 m/s

Velocity Variation

Elevation (m)

Mass

Fract

ion

of

NO

x



For more details on the distribution of NOx mass fraction

can be seen in Fig. 9 which explains the magnitude of NOx

mass fraction to the height of the furnace. The data taken is

NOx data in the middle of the furnace from the bottom ash to

the superheater inlet.

Fig.10 illustrates the NOx mass fraction at the boiler outlet

before the highest preheater water, where for a variation of

26 m/s is 0,000976 and the lowest at a variation of 30 m/s is

0.00000402.

IV. CONCLUSION

The simulation results show that the effect of increasing

the velocity outlet of pulverizer on the combustion

temperature in the furnace (without changing secondary

water) is inversely proportional. The greater the velocity

outlet of pulverizer, the lower the combustion temperature in

the furnace. The combustion temperature at super heater inlet

temperature for existing model is 1218oC, meanwhile the

variation 23 m/s is 1433oC, the variation 24 m/s is 1438oC,

the variation 26 m/s is 1434oC, the variation 28 m/s is 1257oC, the variation 30 m/s s is 1106oC, and the variation of

32 m/s are 592oC.

The NOx mass fraction that occurs at the boiler outlet for

the existing model is 0.001991, while the variation 23 m/s is

0.000507, the variation 24 m/s is 0.00671, the variation 26

m/s is 0.00976, the variation 28 m/s is 0.00727, the variation

30 m/s is 0.00000402, and the variation of 32 m/s is

0.000163

From the analysis of numerical simulation results, the

recommended model design is a variation of the velocity

outlet of pulverizer with a speed of 28 m/s because it has a super heater inlet temperature slightly above the existing

model, so that the use of super heater and reheat spray only

slightly adds to the existing model while for NOx mass

fraction boiler output is about 35% of the existing model.

ACKNOWLEDGMENTS

This research did not receive any specific grant from

funding agencies in the public, commercial, or not-for-profit

sectors. Also, the authors have declared no conflict of

interest.

NOMENCLATURE Abbreviation

AR as received

CFD Computational Fluid Dynamic

DCS Distribute Control System

LRC Low Rank Calories

MRC Medium Rank calories

MSM Medium Speed Mill

OVA Separated Over fire Air

PA Primary air

SA Secondary air

wt % weight percent

REFERENCES [1]. Blondeau, J. et al., “Burner air-fuel ratio monitoring in large

pulverised-fuel boiler”. Thermal Science and Engineering Progress.

Vol. 5, March (2018), pp. 471-481.

(https://doi.org/10.1016/j.tsep.2018.02.006).

[2]. Choi, C.R., and Kim, C.N., “Numerical investigation on the flow,

combustion and NOx emission characteristics in a 500MWe

tangentially fired pulverized-coal boiler”. Fuel. Vol. 88, Issue 9,

September (2009), pp. 1720-1731.

(https://doi.org/10.1016/j.fuel.2009.04.001).

[3]. Al-Abbas , A.H. and Naser, J., “Computational Fluid Dynamic

Modeling of a 550 MW Tangentially-Fired Furnace under Different

Operating Conditions”. Procedia Engineering, Vol. 56, (2013), pp.

387-392.

(https://doi.org/10.1016/j.proeng.2013.03.137).

[4]. Liu, Y.C., Fan, W.D., and Wu, M.Z., “Experimental and numerical

studies on the gas velocity deviation in a 600 MW tangentially fired

boiler”. Applied Thermal Engineering. Vol. 110, January (2017), pp.

553-563.

(https://doi.org/10.1016/j.applthermaleng.2016.08.185)

[5]. Chernetskiy, M., Dekterev, A., Chernetskaya, N., and and Hanjalić,

K., “Effects of reburning mechanically-activated micronized coal on

reduction of NOx: Computational study of a real-scale tangentially-

fired boiler”. Fuel. Vol. 214, February (2018), pp. 215-229.

(https://doi.org/10.1016/j.fuel.2017.10.132).

[6]. Li, D., et al., “Effects of Coal Blending and Operating Conditions on

Combustion and NOx Emission Characteristics in a Tangentially-

fired Utility Boiler”. Energy Procedia. Vol. 105, May (2017), pp.

4015-4020. (https://doi.org/10.1016/j.egypro.2017.03.846).

[7]. Babcock and Wilcox company (2005). Steam its Generation and Use

41st Edition. McDermott Company. Ohio, USA.

[8]. Li, Z., Miao, Z., Zhou, Y., We, S., and Li, J., “Influence of increased

primary air ratio on boiler performance in a 660 MW brown coal

boiler”. Energy, Vol.152, June (2018), pp.804-817.

(https://doi.org/10.1016/j.energy.2018.04.001).

[9]. Xu, M., Azevedo, J.L.T, and Carvalho, M.G., “Modeling of the

combustion process and NOx emission in a utility boiler”. Fuel, Vol.

79, Issue 13, (2000), pp. 1611-1619.

(https://doi.org/10.1016/S0016-2361(00)00019-3).

[10]. Li, Z., Miao, Z., Shen, X., and Li, J., ”Effects of momentum ratio

and velocity difference on combustion performance in lignite-fired

pulverized boiler”. Energy. Vol. 165, Part A, December (2018), pp.

825-839. (https://doi.org/10.1016/j.energy.2018.09.082).

[11]. Kim, G.M., Jeong, J.W., Jeong, J.S., Kim, D.Y., Kim, S.M., and

Jeon, C.H., “Empirical Formula to Predict the NOx Emissions from

Coal Power Plant using Lab-Scale and Real-Scale Operating

Data”. Appl. Sci. 2019, 9 (14), 2914.

(https://doi.org/10.3390/app9142914).

[12]. Ji et al., “Predictions of NOx/N2O emissions from an ultra-

supercritical CFB boiler using a 2-D comprehensive CFD

combustion model”. Particuology, June (2019).

(https://doi.org/10.1016/j.partic.2019.04.003).

[13]. Hart, J., Bhuiyan, A.A., and Naser, J., “Aerodynamics of burner jet

in a tangentially-fired boiler: A CFD modeling and experiment”.

International Journal of Thermal Sciences, Vol. 129, July (2018), pp.

238-253.

(https://doi.org/10.1016/j.ijthermalsci.2018.02.030).

[14]. Li, Z., and Miao, Z., “Primary air ratio affects coal utilization mode

and NOx emission in lignite pulverized boiler”. Energy. Vol. 187,

15 November (2019), 116023.

(https://doi.org/10.1016/j.energy.2019.116023).

[15]. DONGFANG Boiler Group Co, LTD (2008) 96M-3SM Combustion

Equipment Instruction.

[16]. Hachenberg, N, “Predictions of NOx emissions in pulverized coal

combustion”. Electronic Theses and Dissertations. Paper 557.

(https://doi.org/10.18297/etd/557).

https://doi.org/10.1016/j.tsep.2018.02.006

https://www.sciencedirect.com/science/journal/00162361

https://www.sciencedirect.com/science/journal/00162361/88/9

https://doi.org/10.1016/j.fuel.2009.04.001


https://www.sciencedirect.com/science/journal/18777058/56/supp/C

https://doi.org/10.1016/j.proeng.2013.03.137



https://doi.org/10.1016/j.applthermaleng.2016.08.185

https://doi.org/10.1016/j.fuel.2017.10.132



https://doi.org/10.1016/j.egypro.2017.03.846



https://doi.org/10.1016/j.energy.2018.04.001

https://doi.org/10.1016/S0016-2361(00)00019-3)


https://www.sciencedirect.com/science/journal/03605442/165/part/PA

https://doi.org/10.1016/j.energy.2018.09.082

https://doi.org/10.3390/app9142914


https://doi.org/10.1016/j.partic.2019.04.003



https://doi.org/10.1016/j.ijthermalsci.2018.02.030



https://doi.org/10.1016/j.energy.2019.116023

https://doi.org/10.18297/etd/557

Numerical Study of the Effect of Primary Air Velocity of Pulverizer...

Documents

Transcript of Numerical Study of the Effect of Primary Air Velocity of Pulverizer...