煤粉密相气力输送弯管流动特性

王翀; 陆海峰; 郭晓镭; 刘海峰; 龚欣

doi:10.14135/j.cnki.1006-3080.20201009002

煤粉密相气力输送弯管流动特性

doi: 10.14135/j.cnki.1006-3080.20201009002

华东理工大学上海煤气化工程技术研究中心，上海 200237

基金项目: 国家自然科学基金资助项目(51876066)；国家重点研发计划资助(2018YFC0808500)；上海煤气化工程技术研究中心(18DZ2283900)；中央高校基本科研业务费专项资金

详细信息

作者简介:
王翀：王　翀(1995-)，男，浙江杭州人，硕士生，从事密相气力输送研究。E-mail：717022137@qq.com

通讯作者:
陆海峰，E-mail：luhf@ecust.edu.cn

中图分类号: TQ54
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出版历程
- 收稿日期: 2020-10-09
- 网络出版日期: 2021-01-19
- 刊出日期: 2021-12-30

Flow Characteristics of Dense Phase Pneumatic Conveying of Pulverized Coal through the Bend

Shanghai Engineering Research Center of Coal Gasification, East China University of Science and Technology, Shanghai 200237, China

摘要

摘要: 在自主搭建的工业级管径（内径50 mm）气力输送实验平台上开展了密相气力输送实验，对气固两相通过弯管的流动特性进行了研究。借助电容层析成像技术分析弯管出口截面流型特征，发现煤粉流经弯管时管道截面浓度存在明显的径向分布，外壁浓度相对较高。采用附加压降法，并结合对实验数据的回归分析，建立了精度±10%以内弯管压降模型。并基于微元分析和弯管压降分布的基本规律，获得了煤粉浓度沿弯管流动方向的分布特征。
- 密相气力输送 /
- 弯管 /
- 流型 /
- 浓度 /
- 压降
Abstract: Experiments on dense phase pneumatic conveying of pulverized coal were carried out in the self-built pneumatic conveying facility with an industrial pipe diameter of 50 mm. The gas-solid two-phase flow characteristics through the bend were studied. With the help of Enick and Klinzing model, the entrance length of gas-solid two-phase flow in a bend outlet was calculated. It was found that the fluid flow to the electrical capacitance tomography (ECT) was not fully developed, and the fluid was affected by the bend. The flow patterns of the outlet section of the bend were analyzed in the means of ECT, and it was found that the flow pattern changed from the packed bed flow to the unstable/stable plug flow with the increase of the superficial gas velocity. Due to the influence of inertial force and centrifugal force, there was an obvious radial distribution in the concentration of the pipe section when the pulverized coal flowed through the bend, while the coal concentration on lateral wall surface was relatively high. Regression analysis of experimental data was carried out using pressure drop model and dimensional analysis method, a pressure drop model of pulverized coal dense phase pneumatic conveying bend was established by providing errors most smaller than ±10%. Finally, based on micro element analysis and pressure drop distribution along the bend, the distribution characteristics of pulverized coal concentration along the bend were obtained. This work may provide important guiding significance in reducing the wear of bend.
- dense phase pneumatic conveying /
- bend /
- flow pattern /
- concentration /
- pressure drop

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图 1 实验装置图

1—Air compressor; 2,4—Buffer tank; 3—Dryer; 5—Gas distributor; 6—Gas flow meter；7—Filter; 8—Feeding vessel; 9—Pressure sensor; 10—Solid mass flow meter; 11—ECT sensor; 12—Receiving vessel; 13—Weighing sensor

Figure 1. Diagram of experimental equipment

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图 2 表观气速与固气比关系图

Figure 2. Relationship between superficial gas velocity and ratio of solid and gas

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图 3 ECT处流型以及截面相对平均浓度分布图

Figure 3. Flow pattern and relative average concentration distribution of cross section at ECT

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图 4 弯管压降实验值与计算值比较

Figure 4. Comparison of experimental value and calculated value of pressure drop of bend

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图 5 弯管结构示意图及压力的沿程变化图

Figure 5. Schematic diagram of bend pipe structure and trend of pressure drop along the distance

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图 6 压力、浓度沿管道变化趋势图

Figure 6. Trend diagram of pressure and concentration along the pipeline

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表 1 煤粉的物料性质

Table 1. Material properties of pulverized coal

d_v/μm	d_s/μm	d₁₀/μm	d₅₀/μm	d₉₀/μm	ρ_p/(kg·m⁻³)	Moisture mass fraction/%
40.30	4.83	2.07	17.42	115.30	1627.50	1.15

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表 2 实验工况表

Table 2. Experimental condition

Case	Q₂/(m³·h⁻¹)	Q₃/(m³·h⁻¹)	W_s/(kg·h⁻¹)	p_T/kPa	U_g/(m·s⁻¹)	∆p₁/kPa	$ \dfrac{{\Delta {p_2}}}{{{L}}}$/(kPa·m⁻¹)	p/kPa	μ/(kg·kg⁻¹)
1	15.75	0	4659.85	68.22	1.09	10.21	5.64	39.79	328.23
2	16.34	5.73	4161.88	62.15	1.76	8.61	3.90	49.65	170.14
3	16.07	16.41	3980.70	91.63	2.20	7.30	2.94	79.34	110.92

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表 3 L_e计算表

Table 3. Calculation of L_e

Case	U_g/(m·s⁻¹)	ρ_g/(kg·m⁻³)	Re	L_e/mm
1	1.09	1.80	5480.45	2506.37
2	1.76	1.93	9488.27	1731.07
3	2.20	2.31	14195.53	1115.49

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