Numerical Analysis of Performance of Cyclone-Tube Demister Based on Orthogonal Design

doi:10.12141/j.issn.1000-565X.220655

Abstract

Abstract:

Facing the increasingly strict requirements of industrial flue gas emission in China, this paper designed a new type of cyclone-tube demister to overcome the low removal efficiency of fine droplets that particle size less than 20 μm by wave-plate demister. The flow of flue gas in the cyclone tube demister was numerically simulated by using Euler-Lagrangian method, using rigid spherical water drops instead of fog drops. And the RNG k-ε model and DPM model were used for the alternating coupling calculation of continuous phase and discrete phase. The performance changes of the cyclone-tube demister under different flow velocities were studied. Based on the simulation experiment of orthogonal design, the influence of the structural parameters of the cyclone-tube demister on the demisting performance was studied. The simulation results of basic structure cyclone-tube demister show that, under the flow rate of 3~7 m/s, the removal efficiency of droplets with diameter greater than 20 μm is more than 99%; the removal efficiency of droplets with a diameter of 10~20 μm is above 86.5%; the removal efficiency of droplets with a diameter of 2~10 μm is above 51.3%; when the pressure drop is 61.4~321.3 Pa, it can significantly improve the removal efficiency of fine droplets. By analyzing the results of orthogonal simulation test, it is found that the increase of a and the decrease of d are beneficial to improve the removal efficiency of droplets. With the increase of a, d and H, the pressure drop of flue gas flowing through the demister will be increased. The optimum structure with demister efficiency of 2~10 μm as index is d=100 mm, H=2 000 mm, a=900°, the optimum structure with demister efficiency of 10~20 μm as index is d=100 mm, H=1 600 mm, a=900°, the optimum structure with the pressure drop as index d=100 mm, H=2 400 mm, a=540° are obtained. The cyclone-tube demister proposed in this study can significantly improve the removal efficiency of fine droplets, which is of great significance to the ultra clean emissions of coal-fired power plants.

Key words: cyclone-tube demister, demisting performance, gas-liquid flow, numerical simulation, orthogonal test

CLC Number:

TQ028.8

LIU Dingping, ZHANG Xiangyang, CHEN Aihua, et al. Numerical Analysis of Performance of Cyclone-Tube Demister Based on Orthogonal Design[J]. Journal of South China University of Technology(Natural Science Edition), 2023, 51(6): 89-96.

Figures/Tables 10

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结构参数	取值		取值
L₁	200 mm	D	500 mm
L₂	200 mm	x	0.75d
H	2 000 mm	a	720°
d	200 mm

试验号	影响因素				模拟结果
试验号	d/mm	H/mm	a/（°）	Ω	η_2~10/%	η_10~20/%	压降/Pa
1	100	2 000	720	5	64.86	95.06	96.13
2	100	1 800	630	3	59.40	93.93	93.37
3	150	2 000	540	4	57.07	91.80	94.42
4	200	1 600	630	4	46.42	91.52	183.76
5	250	2 000	630	2	55.81	92.71	186.84
6	200	2 400	540	2	53.62	88.34	98.99
7	200	2 000	810	3	54.93	94.91	207.00
8	250	2 200	720	4	57.93	95.37	202.12
9	300	2 200	540	3	48.46	85.18	178.90
10	150	2 200	630	1	51.44	90.51	99.45
11	200	2 200	900	5	57.11	95.47	213.36
12	250	1 600	900	3	58.45	97.97	481.45
13	300	1 800	810	4	57.30	97.14	438.05
14	300	2 000	900	1	60.35	97.65	441.09
15	150	2 400	720	3	52.78	92.27	107.45
16	300	2 400	630	5	52.71	90.19	186.72
17	100	2 200	810	2	66.54	95.94	102.84
18	100	2 400	900	4	70.70	96.28	108.75
19	100	1 600	540	1	53.90	91.98	85.27
20	250	2 400	810	1	60.44	96.15	223.14
21	300	1 600	720	2	53.85	96.02	439.58
22	150	1 800	900	2	63.20	97.54	195.35
23	200	1 800	720	1	61.14	97.13	196.36
24	250	1 800	540	5	40.51	84.10	178.04
25	150	1 800	810	5	58.57	96.65	192.15

分析参数	d	H	a	Ω
κ₁	315.40	271.19	253.56	287.27
κ₂	283.06	281.55	265.78	293.02
κ₃	273.22	293.02	290.56	274.02
κ₄	273.14	281.48	297.78	289.42
κ₅	272.67	290.25	309.81	273.76
z₁	63.080	54.238	50.712	57.454
z₂	56.612	56.310	53.156	58.604
z₃	54.644	58.604	58.112	54.804
z₄	54.628	56.296	59.556	57.884
z₅	54.534	58.050	61.962	54.752
R	42.73	21.83	56.25	19.26
排秩	2	3	1	4

分析参数	d	H	a	Ω
κ₁	473.19	474.15	441.40	473.42
κ₂	468.78	469.85	458.86	470.57
κ₃	467.37	472.13	475.86	464.26
κ₄	466.30	462.47	480.79	472.11
κ₅	466.19	463.23	484.920	461.47
z₁	94.638	94.830	88.280	94.684
z₂	93.756	93.970	91.772	94.114
z₃	93.474	94.426	95.172	92.852
z₄	93.260	92.494	96.158	94.422
z₅	93.238	92.646	96.984	92.294
R	7.00	11.68	43.52	11.95
排秩	4	3	1	2

分析参数	d	H	a	Ω
κ₁	486.36	1 382.21	635.62	1 045.31
κ₂	688.82	1 101.17	750.14	1 023.60
κ₃	899.47	1 025.48	1 041.64	1 068.17
κ₄	1 271.59	796.67	1 163.18	1 027.10
κ₅	1 684.34	725.05	1 440.00	866.40
z₁	97.272	276.442	127.124	209.062
z₂	137.764	220.234	150.028	204.720
z₃	179.894	205.096	208.328	213.634
z₄	254.318	159.334	232.636	205.420
z₅	336.868	145.010	288.000	173.280
R	1 197.98	657.16	804.38	201.77
排秩	1	3	2	4