Characteristics of Pressure Drop of Charred Layer in Coke Dry

Article pubs.acs.org/EF

Characteristics of Pressure Drop of Charred Layer in Coke Dry Quenching over Coke Oven Gas Guojie Zhang,*,†,‡ Peiyu Zhao,† Ying Xu,† and Yongfa Zhang† †

Key Laboratory of Coal Science and Technology, Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024, P. R. China ‡ State Key Laboratory of Coal and CBM Co-Mining, Jincheng 048012, P.R. China ABSTRACT: In a self-designed experimental apparatus, coke oven gas, H2, CO, CH4, CO2, and N2 as coke dry quenching medium, coke as the bed filler, and the influences of particle shape, particle size, the gas flow, and gas species on the bed pressure drop characteristics were investigated. Furthermore, the mathematical model of coke bed pressure drop of coke dry quenching by coke oven gas was established. The results show that coke bed pressure drop increases with the increasing of the gas flow and decreases with the coke particle size increasing. When the gas flow is larger and the particle size of the coke is smaller, the coke bed pressure drops obvious change. It was also found that the coke bed pressure drop has a direct relationship with gas properties, such as density, viscosity, and so on. For the different gas (H2, CO, CH4, CO2, and N2) in the same bed thickness of coke, the order of bed pressure drop has the following relationship: PCO2 > PN2 ≈ PCO > PCH4 > PH2. Under the coke oven gas as coke dry quenching medium, the mathematical model of coke bed pressure drop of coke dry quenching by coke oven gas is μu ΔP established as following, L = kβ d 2 Repn Compared to the classic Ergun empirical formula, the bed pressure data obtained by the p

equation established in this paper would result in a better fit to the data points. In the 1930’s, Ergun put forward the fixed bed pressure drop model and established the following equation:14

1. INTRODUCTION China is a coke production country.1,2 The coke output was 0.45 billion of tons in 2015. At present, most coking plants use wet quenching technology, which not only wastes heats of high-temperature coke but also causes dust pollution caused by steam evaporation in the quenching process. Compared to wet quenching, dry quenching technology can reduce pollution and CO2 emission as well as improve coke quality and energy utilization.3−6 Since Bao Steel introduced the dry quenching device in 1985, dry quenching technology has not been popularized in China.7 Only about 18% coking plants are using dry quenching technology for the moment. This is mainly caused by its high investment and operation cost. To take full advantage of dry quenching technology, it is necessary to improve the dry quenching device and reduce investment and operation cost. To solve these problems, we developed a new dry quenching technology for coke oven gas.8,9 Pressure drop of charred layer in the dry quenching furnace is an important parameter to evaluate the dry quenching system and an important measurement index of energy consumption and the running cost.3,4,10−12 The pressure drop of charred layer in the dry quenching furnace was calculated by the following empirical formula which was proposed by the National Coking Design Institute of the former Soviet Union:13 5.9v 0.45u1.55S1.45ρg ΔP = L ε3

μ(1 − ε)2 ρ(1 − ε) ΔP = 150 u + 1.75 L (d p)2 ε 3 (d p)ε 3

where ρ and μ are the density and viscosity, respectively, of the fluid and dp is the diameter of a different hypothetical sphere having the average volume of the actual particles. This equation was widely accepted for a long time. However, the Ergun equation was obtained under a large bed aspect ratio. Results under different bed aspect ratios will differ significantly. Besides, this equation is also influenced by particle shape. Song et al. made a numerical simulation on pressure loss of charred layer in the dry quenching furnace by using the computational fluid dynamics (CFD) software based on Ergun equation.15 They also found that the Ergun equation had certain limitations on applications of nonspherical large coke particles. Zhao et al. introduced the gas state parameter based on the Ahmed-Sunada equation and improved the Ergun equation, getting the pressure drop formula of gas in fixed bed.16 In accordance with this formula, pressure drop of the bed is inversely proportional to pressure level in the bed. The total pressure drop under certain bed height could be gained through numerical integration. Under isothermal conditions, the analytical expression of total pressure drop of the bed is as follows: ⎛ χ ⎞L P (1 − ε) ΔP = ⎜⎜ + γ ⎟⎟ 1.75 0 3 ρu 2 Pε ⎝ Rep ⎠ dp

(1)

where Δp/L is the pressure drops per unit height bed (Pa/m), υ is the dynamic viscosity of gases (m2/s), u is the average velocity of a gas (m/s), ρg is the density of the fluid (kg/m3), S is the surface area of the porous medium perpendicular to the flow direction, (m2/m3), and ε is the porosity of the porous medium. © XXXX American Chemical Society

(2)

(3)

Received: December 11, 2016 Revised: February 4, 2017 Published: February 24, 2017 A

DOI: 10.1021/acs.energyfuels.6b03286 Energy Fuels XXXX, XXX, XXX−XXX

Article

Energy & Fuels where χ and γ are model parameters, P0 is the pressure at the environmental state (1.01325 bar), P is the average value of bed inlet and outlet pressure, L is the height of the medium, and Rep is the Reynolds number. The research indicates that for the bed with different particle shapes, there are significant differences between the coefficients α and γ, which reflects the influence of particle shape (including roughness) on bed pressure drop. Pressure drop of beds with different particle shapes is the collaborative consequence of multiple factors. Porosity of the bed is the biggest influencing factor.17−19 Although people have established several bed pressure drop models in dry quenching furnace, these models use nitrogen as the dry quenching carrier. Little research on reducing gas has been reported. With the newly developed dry quenching technology or coke dry quenching over coke oven gas technology, a bed pressure drop model was established on the basis of theoretical derivation. This model used main components of the coke oven gas (H2, CO, CH4, CO2, and N2) as the dry quenching media and used coke as the bed filler. Effects of particle shape, size, and gas flow on bed pressure drop were analyzed.

Table 2. Parameters of Different Particle-Size Coke number

dr (mm)

WT (kg)

dp (mm)

ε (%)

1 2 3 4 5

3−6 6−10 10−13 13-21 21−25

2.82 2.56 2.54 2.34 2.17

4.50 8.00 11.50 17.00 23.00

49.07 53.77 54.13 57.74 60.81

2. EXPERIMENTAL SECTION The evaluation device of bed pressure drop in the dry quenching furnace is shown in Figure 1. The inner diameter and height of the dry

Figure 2. log

ΔP / L μu / d p2

vs log Rep relationships under different coke

particle sizes and gas atmospheres.

Table 3. Value of k and n under the Different Bed Voidage ε ε k n

60.81% 50.68 0.73

57.74% 78.95 0.73

54.13% 75.18 0.75

53.77% 110.58 0.67

49.07% 332.02 0.51

Figure 1. Process flow diagram of coke dry quenching system. quenching furnace are 80 mm and 1.0m, respectively. Dry quenching used N2, H2, CO, CH4, and CO2 or coke oven gas at a flow rate of 1.6−18 m3/h. The used coke was collected from the second coking plant of Shanxi Taiyuan Gasification Company. The industrial analysis and element analysis are shown in Table 1. Effect of coke particle size

Table 1. Proximate Analysis and Ultimate Analysis of Coke proximate analysis/wt %, ad

Ultimate analysis/wt %, ad

moisture

ash

volatile

carbon

H

N

S

O(diff)

0.62

13.8

2.47

81.7

0.92

0.37

0.85

1.74

Figure 3. Correlations between k, n, and ε.

(3−6, 6−10, 10−13, 13−21, and 21−25 mm) on bed pressure drop in the dry quenching furnace was investigated. The porosity of coke is measured according to KS EISO 1014−2002 “Coke -- Determination of true relative density, apparent relative density and porosity”. Loading level of different particle-size coke and the bed porosity are listed in Table 2. Bed pressure drop in the dry quenching furnace was tested by a YYT-2000B-type tilting differential pressure gauge. The reproduction of the experimental results was more than 97%, and all experiments with large errors were rejected.

3. ESTABLISHMENT OF THE BED PRESSURE DROP MODEL 3.1. Establishment of a Mathematical Model of Bed Pressure Drop in Dry Quenching Furnace. Pressure drop of the coke bed in the dry quenching furnace has certain relationships with gas composition of dry quenching as well as density, viscosity, molecular weight, and gas flow rate of components and B


Article

Energy & Fuels

Figure 4. Test of the established mathematical model and Ergun equation with the data.

bed materials.20−25 To further determine the quantitative relationship between bed pressure drop and physical quantity, a dimensional analysis on influencing factors of bed pressure drop was carried out first. In accordance with the correlation analysis of hydraulic resistance, the bed pressure drop is mainly related to following factors. The corresponding mathematical functional equation could be expressed as ΔP = f (dp , ε , ρ , u , μ) L

If

and Rep is a power function, eq 5 can be expressed as

ΔP /L = Renp f (ε) μu/d p2

(6)

Calculate logarithm of two sides of eq 6, then, log

(4)

In the Ergun equation, dp, ρ, u, and μ are related with Reynolds dimensionless number of particles Rep. Both ε and Rep are dimensionless factors. In accordance with the principle of dimensional consistency, eq 4 can be rewritten as ΔP /L = f (Re p)f (ε) μ u/d p2

ΔP / L μu / d p2

ΔP /L = n log Rep + log f (ε) μu/d p2

If eq 7 is true, log

ΔP / L -log μu / d p2

3.2. Verification of

(7)

Rep is a straight line.

ΔP / L log μu / d p2

Rep. The log

ΔP / L −log μu / dp2

Rep relationships under different coke particle sizes and gas atmospheres are shown in Figure 2.

(5) C


Article

RE (%)l

12.27 5.29 1.74 2.65 5.53 6.61 5.68

TMCD

67.18 86.90 108.61 132.22 157.66 184.86

ED

9.44 3.89 2.73 1.84 0.86 1.02 3.30 201.67 265.59 335.20 410.08 489.90 574.38

76.58 91.75 110.53 135.82 166.89 197.95 average relative error

RE (%) TMCD ED

222.70 276.34 344.61 417.76 494.16 580.31 average relative error 42.22 42.11 43.47 45.51 46.46 44.27 44.01 22.54 27.60 33.08 38.97 45.26 51.94

RE (%) TMCD ED


N2

CO

CH4

CO2

coke oven gasa

0.85

1.00

1.21

1.82

1.05

1.13

The composition of the coke oven gas is 60% H2, 25% CH4, 5% CO, 3% CO2 and 7% N2.

It can be known from the above five groups of experimental ΔP / L data that in the same bed, log μu / d 2 vs log Rep gives straight p

line plots, indicating the above hypotheses are true. Let f(ε) = k, so the bed pressure drop is

μu ΔP = k 2 Renp L dp

29.69 14.21 20.23 13.17 16.53 12.13 17.66 8.43 12.38 16.94 22.08 27.78 34.02 6.50 10.84 14.09 19.51 23.84 30.34 average relative error

(8)

3.3. Determination of the Model Equation. The k and n could be gained from the above five groups of bed experimental data (Table 3). It can be seen from Table 3 that k and n under the five groups of bed pressure drops are different, indicating that they have certain relationships with the bed porosity. In accordance with the experimental data fitting (Figure 3), the relationship of k, n, and ε is n = −6.8 + 25.5ε − 21.6ε 2

k = 11289 − 38577ε + 33084ε 2

Substitute n and k into eq 8 and the mathematical model of the bed pressure drop could be gained: μu ΔP = (11289 − 38577ε + 33084ε 2) 2 L dp 2

× Re p(−6.8 + 25.5ε − 21.6ε )

16.99 16.73 12.45 14.14 13.13 11.66 14.18

RE (%)

β

H2 a

(9)

4. RESULTS AND DISCUSSION 4.1. Comparison of Experimental Results, Modeling Equation and E Empirical Equation. To verify reliability of the modeling equation, the mathematical modeling equation results were compared with experimental results and E empirical equation results (Figure 4). In Figure 4, compared to the Ergun empirical equation results, the mathematical model results and experimental results are closer. Moreover, the model results were basically consistent with experimental results when CO2 and N2 were used as the dry quenching atmosphere. When H2, CO, and CH4 were used as the dry quenching atmosphere, the model results have certain deviation with experimental results as shown in Table 4. From Table 4, it can be found that the average relative error of bed pressure drop is 17.66%, 14.18%, 44.01%, 3.30%,and 5.68% in H2, CO, CH4, N2, and CO2, respectively. This is mainly because the bed pressure drop is also related with the gas type except for coke particle size, bed porosity, gas density, viscosity, and gas flow rate. It can be known from the Van Der Waals equa-

54.87 68.58 83.49 99.55 116.73 134.98

TMCD relative error (RE) (%) theoretical model calculation data (TMCD) experimental data (ED)

ED

Table 5. Calculated Calibration Factors of Different Gases


CH4 CO H2

Table 4. Comparison of Experimental Data, Theoretical Model Calculations, and Relative Errors in Different Gases

N2

CO2

Energy & Fuels

(

tion p +

a Vm2

)(V

m

− b) = RT that different attractions of gas

molecules and molecular volumes will cause changes of bed pressure drop.26,27 In addition, different interactions between different gases and coke will cause changes of bed pressure drop. To make the established mathematical model agree with experimental results as much as possible, the calibration factor (β) of different gases was introduced for further optimization of f(ε). The calculated calibration factors of different gases are D


Article

Energy & Fuels

Figure 5. Correlation between bed pressure drop and gas flow rate under different dry quenching gas conditions.

pressure loss of gases after flowing through the coke bed is related with gas type and flow rate to some extent. In the dry quenching furnace, the trend of gas flow rate with the bed pressure drop under different dry quenching gas conditions is presented in Figure 5. It can be seen from Figure 5 that although the bed pressure under different atmospheres is different, the overall trend is the same and the bed pressure drop increases with the increase of gas flow rate. This is because viscous frictional resistance is the main flow resistance against fluid flowing through the bed and the flow is viscous in most cases.28−31 At viscous flow, the bed pressure drop is proportional to flow rate. Besides, bed pressure drop of different gases may be related to the molecular

shown in Table 5. From Table 5, it can be found that the calibration factor (β) of coke oven gas is only 1.13. This indicates that the deviation between the theoretical model calculation value and the experimental is relatively small in the coke oven gas as a coke dry quenching atmosphere. Finally, the bend pressure drop model in a dry quenching furnace is 2

(−6.8 + 25.5ε − 21.6ε ) μu ⎛ d pρu ⎞ ΔP = (11289 − 38577ε + 33084ε 2)β 2 ⎜ ⎟ L dp ⎝ μ ⎠

(10)

4.2. Effects of Different Gas Type and Flow Rate on Bed Pressure Drop. In accordance with the hydromechanics, E


Article

Energy & Fuels

Figure 6. Effects of coke particle size on bed pressure drop under different dry quenching atmospheres.

that of H2. In the CH4 molecule, C forms four σ bonds by overlapping between four sp3 hybrid orbits and 1s of 4 H atoms. Viewed from the atom overlapping, bond energy of the π bond is smaller than that of the σ bond, so the π bond is less stable than the σ bond and the bend pressure drop of CH4 is between H2 and N2. In the CO2 molecules, the C atom uses sp hybrid orbitals to form bonds with O atoms. The p orbitals and the sp hybrid orbital on the C atom which did not participate in hybridization are mutually perpendicular and form side-by-side overlaps with p orbitals of the O atom from the profile, producing two groups of three-orbital and four-electron big π bonds.

structure of the gas. The heteronuclear diatomic CO has 14 electrons, which is same of N2 molecules and belongs to isoelectronic species. The structure and property of the CO molecular orbit are similar to N2, belonging to the triple bond. Therefore, CO and N2 have similar bed pressure drops. H2 and N2 are diatomic molecules. In H2 molecules, s-s orbits overlap into “head-to-head” σ covalent bond. The N2 molecule forms one σ bond and two π bonds, developing a covalent triple bond. Since there are abundant bonding electrons in the triple bond and the electron cloud occupies a large space and has a strong repulsive force, the bed resistance of N2 is stronger than F


Article

Energy & Fuels ORCID

These shorten the distance between C−O atoms, so that the C−O bond in CO2 has some triple bond features. This may be the biggest cause of pressure drop of the CO2 bed in the above gases. In Figure 5, the pressure drop sequence of different gases under above five coke particle sizes remains the same: PCO2 > PN2 ≈ PCO > PCH4 > PH2. This is because under the same conditions, the bed pressure drop of different gases is directly related with gas properties (density and viscosity). Under the same conditions, the density order of different gases is ρCO2 (1.83 kg/m3) > ρN2 (1.16 kg/m3) > ρCO(1.15 kg/m3) > ρCH4 (0.67 kg/m3) > ρH2 (0.08 kg/m3) and the viscosity order is μN2 (1.76 × 10−5 Pa s) > μCO (1.69 × 10−5 Pa s) > μCO2 (1.47 × 10−5 Pa s) > μCH4 (1.10 × 10−5 Pa s) > μH2 (8.84 × 10−5 Pa s). The order of magnitude of gas viscosity is 10−5. The gas viscosity influences the bed pressure drop slightly and could be neglected. Therefore, the direct relationship between bed pressure drop of different gases and gas properties is mainly reflected on density. 4.3. Effect of Coke Particle Size on Bed Pressure Drop. Effects of coke particle size on bed pressure drop under different dry quenching atmospheres are shown in Figure 6. It can be seen from Figure 6 that under different dry quenching atmospheres, bed pressure drops and coke particle size present the same trend. The bed pressure drop decreases with the increase of coke particle size. This is because of two reasons:32,33 first, smaller coke particle size brings smaller porosity between coke particles, stronger gas flow resistance, and greater pressure loss; and second, a smaller coke particle size leads to larger surface roughness, stronger coke surface-gas frictions, and a larger pressure drop. Moreover, the growth rate of bed pressure drop increases with the increase of gas inflow under same coke particle size. When the gas inflow is relatively small, pressure drop changes are mainly caused by gas flow resistance by coke blocks in the bed pores. With the increase of gas flow rate, it is necessary to overcome coke resistance and resistance against fluid flowing in spaces of particles. Therefore, the bed pressure drop increases quickly with the growth of flow rate.

Guojie Zhang: 0000-0001-5830-3539 Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (Grants 21376003, 21676174, and U1610115), the National Science & Technology Pillar Program (Grant 2012BAA04B03), and the Joint Fund of Shanxi Provincial Coal Seam Gas (Grant 2015012019).

■

5. CONCLUSION Research results demonstrated that under all atmospheric conditions, bed pressure drop in the dry quenching furnace is positively correlated with the gas flow rate but is negatively correlated with coke particle size. The higher gas inflow and smaller coke particle size, the more obvious the bed pressure drop changes. The pressure drop order of different gases in the same bed is PCO2 > PN2 ≈ PCO > PCH4 > PH2. Finally, the bed pressure drop equation in a dry quenching device could be gained from the mathematical modeling based on experimental μu ΔP data: L = kβ 2 Renp The established mathematical model d p

results are compared with the Ergun empirical equation and experimental results, and it is found that the established mathematical model could basically reflect the bed pressure drop law of the dry quenching furnace. The proposed mathematical model is more accurate than the classical Ergun empirical equation, which appears to be adequate for a wide variety of unconsolidated porous media. It is likely that the experimental results will lie within ±20% of the predicted values.

■

REFERENCES

(1) Chen, W. H.; Hsu, C. L.; Du, S. W. Thermodynamic analysis of the partial oxidation of coke oven gas for indirect reduction of iron oxides in a blast furnace. Energy 2015, 86, 758−771. (2) Liu, X.; Yuan, Z. Life cycle environmental performance of byproduct coke production in China. J. Cleaner Prod. 2016, 112, 1292− 1301. (3) Sun, K.; Tseng, C. T.; Shan-Hill Wong, D.; Shieh, S. S.; Jang, S. S.; Kang, J. L.; Hsieh, W. D. Model predictive control for improving waste heat recovery in coke dry quenching processes. Energy 2015, 80, 275−283. (4) Errera, M. R.; Milanez, L. F. Thermodynamic analysis of a coke dry quenching unit. Energy Convers. Manage. 2000, 41 (2), 109−127. (5) Kim, J. H.; Lee, Y. J.; Kim, K. S. Modeling for a Coke Dry Quenching Process Using a Theory of a Porous Material. Journal of the Korean Society of Manufacturing Technology Engineers 2012, 21 (5), 697−701. (6) Vogel, C. A.; Ponder, W. H. Environmental tests comparing Kress Indirect Dry-Cooling with conventional Coke Oven Pushing and Quenching. Stud. Environ. Sci. 1994, 61, 397−397. (7) Ching-Han, W. How Baoshan Steel Works commissioned China’s first coke dry quench plant. Steel Times International 1987, 11 (1), 48−49. (8) Zhang, Y. F.; Wang, L. X. Thermal Equilibrium and Characters of Fluid Resistance in CH4 -CO2 Reforming Reactor. Chem. Ind. Eng. 2010, 27 (5), 391−396. (9) Wang, L. X; Zhang, Y. F. Current Status of the Study on Coke Dry quenching technology and coke oven gas coke dry quenching new technology development. Chem. Ind. Eng. Prog. (Beijing, China) 2009, 28 (S1), 74−77. (10) Chelgani, S. C.; Matin, S. S.; Hower, J. C. Explaining relationships between coke quality index and coal properties by Random Forest method. Fuel 2016, 182, 754−760. (11) Buczynski, R.; Weber, R.; Kim, R.; Schwöppe, P. Onedimensional model of heat-recovery, non-recovery coke ovens. Part III: Upper-oven, down-comers and sole-flues. Fuel 2016, 181, 1132− 1150. (12) Roest, R.; Lomas, H.; Mahoney, M. R. Fractographic approach to metallurgical coke failure analysis. Part 2: Cokes from binary coal blends. Fuel 2016, 180, 794−802. (13) Pan, L. H.; Wei, S. B. Coke Dry Quenching Technology, 1st ed.; Metallurgical Industry Press: Beijing, 2005. (14) Ergun, S. Fluid flow through packed columns. Chem. Eng. Prog. 1952, 48, 89−94. (15) Song, B.; Feng, Y. H.; Zhang, X. X.; Xu, L.; Yu, Z. D. Numerical study and experimental verification of the pressure drop of coke bed in CDQ shaft. Industrial Furnace 2007, 6, 1−4. (16) Zhao, Q. G.; Liao, H.; Li, S. F. The Effects of pressure, temperature, and particle shape on the pressure drop in fixed bed. Chem. React. Eng. Technol. 2000, 16 (1), 1−6. (17) Macdonald, I. F.; El-Sayed, M. S.; Mow, K.; Dullien, F. A. L. Flow through porous media-the Ergun equation revisited. Ind. Eng. Chem. Fundam. 1979, 18 (3), 199−208. (18) Dullien, F. A. L. Single phase flow through porous media and pore structure. Chemical Engineering Journal 1975, 10 (1), 1−34.

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected] and [email protected]. G


Article

Energy & Fuels (19) Ahmed, N.; Sunada, D. K. Nonlinear Flow in Porous Media. Journal of the Hydraulics Division Proceedings of the American Society of Civil Engineers 1969, 95, 1847−1857. (20) Ç arpinlioğlu, M.Ö .; Ö zahi, E. A simplified correlation for fixed bed pressure drop. Powder Technol. 2008, 187 (1), 94−101. (21) Zhang, D.; Fan, P.; Wu, D.; Li, Y. Pressure drop across a fixed bed reactor with mechanical failure of catalyst pellets described by simplified ergun’s equation. China Particuol. 2005, 3 (01n02), 23−25. (22) Oda, J.; Akimoto, K.; Sano, F.; Tomoda, T. Diffusion of energy efficient technologies and CO2 emission reductions in iron and steel sector. Energy Economics 2007, 29 (4), 868−888. (23) Bisio, G.; Rubatto, G. Energy saving and some environment improvements in coke-oven plants. Energy 2000, 25 (3), 247−265. (24) Luckos, A.; Bunt, J. R. Pressure-drop predictions in a fixed-bed coal gasifier. Fuel 2011, 90 (3), 917−921. (25) Di Felice, R.; Gibilaro, L. G. Wall effects for the pressure drop in fixed beds. Chem. Eng. Sci. 2004, 59 (14), 3037−3040. (26) Thanh, M. D.; Huy, N. D.; Hiep, N. H.; Cuong, D. H. Existence of traveling waves in van der Waals fluids with viscosity and capillarity effects. Nonlinear Analysis: Theory, Methods & Applications 2014, 95, 743−755. (27) Bira, B.; Sekhar, T. R. Evolution of weak discontinuity in a van der Waals gas. Ain Shams Engineering Journal 2015, 6 (3), 1129−1132. (28) Jena, H. M.; Roy, G. K.; Biswal, K. C. Studies on pressure drop and minimum fluidization velocity of gas−solid fluidization of homogeneous well-mixed ternary mixtures in un-promoted and promoted square bed. Chem. Eng. J. 2008, 145 (1), 16−24. (29) Bendová, H.; Šiška, B.; Machač, I. Pressure drop excess in the flow of viscoelastic liquids through fixed beds of particles. Chem. Eng. Process. 2009, 48 (1), 29−37. (30) Sau, D. C.; Mohanty, S.; Biswal, K. C. Minimum fluidization velocities and maximum bed pressure drops for gas−solid tapered fluidized beds. Chem. Eng. J. 2007, 132 (1), 151−157. (31) Sau, D. C.; Mohanty, S.; Biswal, K. C. Critical fluidization velocities and maximum bed pressure drops of homogeneous binary mixture of irregular particles in gas−solid tapered fluidized beds. Powder Technol. 2008, 186 (3), 241−246. (32) Keyser, M. J.; Conradie, M.; Coertzen, M.; Van Dyk, J. C. Effect of coal particle size distribution on packed bed pressure drop and gas flow distribution. Fuel 2006, 85 (10), 1439−1445. (33) Sun, L. Y.; Liu, Y. D.; Zhai, C.; Zhou, H. Process simulation of an integrated coke dry quenching combined gasification. Petroleum & Coal 2012, 54 (1), 34−41.

H


Characteristics of Pressure Drop of Charred Layer in Coke Dry

Recommend Documents