A logic-based controller for the mitigation of ventilation air methane in a catalytic flow reversal reactor

Abstract

The control system of a catalytic flow reversal reactor (CFRR) for the mitigation of ventilation air methane was investigated. A one-dimensional heterogeneous model with a logic-based controller was applied to simulate the CFRR. The simulation results indicated that the controller developed in this work performs well under normal conditions. Air dilution and auxiliary methane injection are effective to avoid the catalyst overheating and reaction extinction caused by prolonged rich and lean feed conditions, respectively. In contrast, the reactor is prone to lose control by adjusting the switching time solely. Air dilution exhibits the effects of two contradictory aspects on the operation of CFRR, i.e., cooling the bed and accumulating heat, though the former is in general more prominent. Lowering the reference temperature for flow reversal can decrease the bed temperature and benefit stable operation under rich methane feed condition.

Key words： ventilation air methane; reverse flow reactor; lean methane combustion; logic-based controller; mathematical modeling

Acknowledgments

The authors are grateful for the financial supports of National Basic Research Program of China (2010CB226900, 2011CB201400), the National Natural Science Foundation of China (21227002), Natural Science Foundation of Shanxi Province of China (2011011006-3, 2012021005-3).

Nomenclature

an	surface area per unit volume /m2·m-3
CCH4	methane concentration /mol·m-3
CP	heat capacity /(J·kg-1·K-1)
Deff	effective dispersion coefficient /m2·s-1
DR	diameter of reactor /m
h	heat transfer coefficient /(W·m-2·K-1 )
DH	enthalpy of reaction of methane /J·mol-1
km	mass transfer coefficient /m·s-1
k	thermal conductivity /(W·m-1·K-1)
L	reactor length /m
–RCH4	rate of disappearance of methane /(mol·m-3·s-1)
t	time /s
tsw	switching time /s
T	temperature /K
u	superficial gas velocity /m·s-1
Uk	overall heat transfer coefficient /(W·m-2·K-1)
x	axial coordinate /m
Greek letters
a	air dilution term
b	methane injection term
e	porosity
h	effective factor
r	density /kg·m-3
t	tortuosity factor
Superscripts and subscripts
0	time t= 0
f	fluid properties
feed	feed properties
in	inlet properties
max	maximum
out	outlet properties
s	solid properties
Abbreviations
CFRR	catalytic flow reversal reactor
LQR	linear-quadratic regulator
MPC	model predictive control
RFR	reversal flow reactor
RMPC	repetitive model predictive control
STP	standard temperature and pressure
VAM	ventilation air methane

References

1 Karakurt I, Aydin G, Aydiner K. Sources and mitigation of methane emissions by sectors: A critical review. Renewable Energy, 2012, 39(1): 40–48

2 Su S, Beath A, Guo H, Mallett C. An assessment of mine methane mitigation and utilisation technologies. Progress in Energy and Combustion Science, 2005, 31(2): 123–170

3 Gosiewski K, Matros Y S, Warmuzinski K, Jaschik M, Tanczyk M. Homogeneous vs catalytic combustion of lean methane-air mixtures in reverse-flow reactors. Chemical Engineering Science, 2008, 63(20): 5010–5019

4 Karakurt I, Aydin G, Aydiner K. Mine ventilation air methane as a sustainable energy source. Renewable & Sustainable Energy Reviews, 2011, 15(2): 1042–1049

5 Warmuzinski K. Harnessing methane emissions from coal mining. Process Safety and Environmental Protection, 2008, 86(5): 315–320

6 Trimm D. Catalytic combustion. Applied Catalysis A, General, 1983, 7(3): 249–282

7 Pio Forzatti G G. Catalytic combustion for the production of energy. Catalysis Today, 1999, 54(1): 165–180

8 Zhang Y, Qin Z, Wang G, Zhu H, Dong M, Li S, Wu Z, Li Z, Wu Z, Zhang J, Hu T, Fan W, Wang J. Catalytic performance of MnO_x-NiO composite oxide in lean methane combustion at low temperature. Applied Catalysis B: Environmental, 2013, 129(1): 172–181

9 Wang B, Qin Z, Wang G, Wu Z, Fan W, Zhu H, Li S, Zhang Y, Li Z, Wang J. Catalytic combustion of lean methane at low temperature over palladium on a CoO_x-SiO₂ composite support. Catalysis Letters, 2013, 143(5): 411–417

10 Budhi Y W, Jaree A, Hoebink J H B J, Schouten J C. Simulation of reverse flow operation for manipulation of catalyst surface coverage in the selective oxidation of ammonia. Chemical Engineering Science, 2004, 59(19): 4125–4135

11 Grigorios Kolios G E. Styrene synthesis in a reverse-flow reactor. Chemical Engineering Science, 1999, 54(13-14): 2637–2646

12 Dillerop C, van den Berg H, van der Ham A G J. Novel syngas production techniques for GTL-FT synthesis of gasoline using reverse flow catalytic membrane reactors. Industrial & Engineering Chemistry Research, 2010, 49(24): 12529–12537

13 Glöckler B, Kolios G, Eigenberger G. Analysis of a novel reverse-flow reactor concept for autothermal methane steam reforming. Chemical Engineering Science, 2003, 58(3-6): 593–601

14 Matros Y S, Bunimovich G A. Reverse-flow operation in fixed bed catalytic reactors. Catalysis Reviews, 1996, 38(1): 1–68

15 Kolios G, Frauhammer J, Eigenberger G. Autothermal fixed-bed reactor concepts. Chemical Engineering Science, 2000, 55(24): 5945–5967

16 Balaji S, Fuxman A, Lakshminarayanan S, Forbes J F, Hayes R E. Repetitive model predictive control of a reverse flow reactor. Chemical Engineering Science, 2007, 62(8): 2154–2167

17 Devals C, Fuxman A, Bertrand F, Forbes J F, Perrier M, Hayes R E. Enhanced model predictive control of a catalytic flow reversal reactor. Canadian Journal of Chemical Engineering, 2009, 87(4): 620–631

18 Dufour P, Couenne F, Toure Y. Model predictive control of a catalytic reverse flow reactor. Control Systems Technology. IEEE Transactions on, 2003, 11(5): 705–714

19 Dufour P, Touré Y. Multivariable model predictive control of a catalytic reverse flow reactor. Computers & Chemical Engineering, 2004, 28(11): 2259–2270

20 Fuxman A M, Forbes J F, Hayes R E. Characteristics-based model predictive control of a catalytic flow reversal reactor. Canadian Journal of Chemical Engineering, 2007, 85(4): 424–432

21 Edouard D, Hammouri H, Zhou X G. Control of a reverse flow reactor for VOC combustion. Chemical Engineering Science, 2005, 60(6): 1661–1672

22 Fuxman A M, Aksikas I, Forbes J F, Hayes R E. LQ-feedback control of a reverse flow reactor. Journal of Process Control, 2008, 18(7-8): 654–662

23 Edouard D, Dufour P, Hammouri H. Observer based multivariable control of a catalytic reverse flow reactor: comparison between LQR and MPC approaches. Computers & Chemical Engineering, 2005, 29(4): 851–865

24 Fissore D, Barresi A A. Robust control of a reverse-flow reactor. Chemical Engineering Science, 2008, 63(7): 1901–1913

25 Barresi A A, Vanni M. Control of catalytic combustors with periodical flow reversal. AIChE Journal. American Institute of Chemical Engineers, 2002, 48(3): 648–652

26 Hevia M A G, Ordóñez S, Díez F V, Fissore D, Barresi A A. Design and testing of a control system for reverse-flow catalytic afterburners. AIChE Journal. American Institute of Chemical Engineers, 2005, 51(11): 3020–3027

27 Balaji S, Lakshminarayanan S. Heat removal from reverse flow reactors used in methane combustion. Canadian Journal of Chemical Engineering, 2005, 83(4): 695–704

28 Mancusi E, Russo L, Brasiello A, Crescitelli S, di Bernardo M. Hybrid modeling and dynamics of a controlled reverse flow reactor. AIChE Journal. American Institute of Chemical Engineers, 2007, 53(8): 2084–2096

29 Marín P, Ho W, Ordóñez S, Díez F V. Demonstration of a control system for combustion of lean hydrocarbon emissions in a reverse flow reactor. Chemical Engineering Science, 2010, 65(1): 54–59

30 Salomons S, Hayes R E, Poirier M, Sapoundjiev H. Modelling a reverse flow reactor for the catalytic combustion of fugitive methane emissions. Computers & Chemical Engineering, 2004, 28(9): 1599–1610

31 Aubé F, Sapoundjiev H. Mathematical model and numerical simulations of catalytic flow reversal reactors for industrial applications. Computers & Chemical Engineering, 2000, 24(12): 2623–2632

32 Li Z, Qin Z, Zhang Y, Wu Z, Wang H, Li S, Shi R, Dong M, Fan W, Wang J. A control strategy of flow reversal with hot gas withdrawal for heat recovery and its application in mitigation and utilization of ventilation air methane in a reverse flow reactor. Chemical Engineering Journal, 2013, 228: 243–255

33 Vortmeyer D, Jahnel W. Moving reaction zones in fixed bed reactors under the influence of various parameters. Chemical Engineering Science, 1972, 27(8): 1485–1496

34 Froment G F, Bischoff K B. Chemical Reactor Analysis and Design. New York: John Wiley & Sons, 1979, 476