Structure optimization of foam generator for soft coal seam and foaming effect simulation

Authors

JIN Xin, Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Changsha 410083, China; School of Geosciences and Info-Physics, Central South University, Changsha 410083, China; CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, ChinaFollow

Abstract

Objective The application of air screw drilling technology in gas drainage borehole within soft coal seam presents challenges, including severe dust pollution, low drill bit lifespan, and great difficulty in borehole purification. The use of air screw foam drilling technology is an effective way to solve the problem. A foam generator with good foaming performance is one of the keys to implementing the foam drilling technology. However, most current foam generators could not meet the requirements. Methods In response to this issue, a small-sized foam generator was designed based on the spiral foam generator, with an air kinetic energy conversion device increased. Besides, the rationality of the structural design of the air kinetic energy conversion device and the installation angle of the stirring blades in the turbine stirring section were evaluated and optimized using the numerical simulation analysis methods. Results and Conclusions The results show that: (1) The air kinetic energy conversion device could effectively drive the main shaft of the foam generator to rotate, achieving an average rotational speed 621.61 r/min under 0.8 MPa air pressure. (2) After the kinetic energy conversion, the gas can enter the foam generator continuously and mix with the foam base liquid to achieve the design purpose. (3) By comparing and analyzing the trace distribution of the mixed phase, turbulence distribution in the fluid domain, gas phase distribution and bubble size distribution, it is found that a stirring blade with an installation angle of 30° has good stirring efficiency and gas-liquid mixing effect. The research results have established a foundation for the successful application of air screw foam drilling technology in gas drainage boreholes within soft coal seams.

Keywords

soft coal seam, air screw foam drilling, foam generator, air kinetic energy conversion device, stirring blades, numerical simulation

DOI

10.12363/issn.1001-1986.24.05.0301

Recommended Citation

J. (2024) "Structure optimization of foam generator for soft coal seam and foaming effect simulation," Coal Geology & Exploration: Vol. 52: Iss. 8, Article 20.
DOI: 10.12363/issn.1001-1986.24.05.0301
Available at: https://cge.researchcommons.org/journal/vol52/iss8/20

Reference

[1] 赵维国，王继仁，兰天伟，等. 低透气性煤层的渗透率试验与瓦斯抽采技术[J]. 辽宁工程技术大学学报(自然科学版)，2020，39(3)：201−207.

ZHAO Weiguo，WANG Jiren，LAN Tianwei，et al. Permeability test and gas drainage technology of low permeability coal seam[J]. Journal of Liaoning Technical University (Natural Science)，2020，39(3)：201−207.

[2] 袁亮，张平松. 煤炭精准开采地质保障技术的发展现状及展望[J]. 煤炭学报，2019，44(8)：2277−2284.

YUAN Liang，ZHANG Pingsong. Development status and prospect of geological guarantee technology for precise coal mining[J]. Journal of China Coal Society，2019，44(8)：2277−2284.

[3] 徐书荣，刘飞，梁道富，等. 底板梳状钻孔在碎软煤层瓦斯治理中的应用[J]. 探矿工程(岩土钻掘工程)，2019，46(7)：45−50.

XU Shurong， LIU Fei， LIANG Daofu， et al. Application of comb type directional drilling in broken–soft coal seam floor for gas control[J]. Exploration Engineering (Rock & Soil Drilling and Tunneling)，2019，46(7)：45−50.

[4] 叶旭东，黄盛初. 煤炭工业“十三五” 面临的形势及发展重点[J]. 煤炭经济研究，2016，36(7)：11−14.

YE Xudong，HUANG Shengchu. The situation and development priority of coal industry during the 13^th Five-Year Plan period[J]. Coal Economic Research，2016，36(7)：11−14.

[5] 刘春. 松软煤层瓦斯抽采钻孔塌孔失效特性及控制技术基础[D]. 徐州：中国矿业大学，2014.

LIU Chun. Study on mechanism and controlling of borehole collapse in soft coal seam[D]. Xuzhou：China University of Mining and Technology，2014.

[6] 卢平，袁亮，程桦，等. 低透气性煤层群高瓦斯采煤工作面强化抽采卸压瓦斯机理及试验[J]. 煤炭学报，2010，35(4)：580−585.

LU Ping，YUAN Liang，CHENG Hua，et al. Theory and experimental studies of enhanced gas drainage in the high-gas face of low permeability coal multi-seams[J]. Journal of China Coal Society，2010，35(4)：580−585.

[7] 苟治伦，毛薪杰，郭煜. 复杂地质条件采煤工作面过地质构造带瓦斯综合治理技术研究[J]. 煤炭技术，2021，40(1)：96−98.

GOU Zhilun，MAO Xinjie，GUO Yu. Study on comprehensive gas control technology of coal face passing through geological structure zone under complex geological conditions[J]. Coal Technology，2021，40(1)：96−98.

[8] 杜子健，刘子龙. 煤矿井下顺煤层千米枝状长钻孔抽采瓦斯技术[J]. 矿业安全与环保，2007，34(1)：27−30.

DU Zijian，LIU Zilong. Gas drainage from underground mine with 1000m branched long holes along seam[J]. Mining Safety & Environmental Protection，2007，34(1)：27−30.

[9] 孙利海. 碎软煤层空气定向钻进工艺最小供风流量[J]. 煤矿安全，2021，52(7)：175−180.

SUN Lihai. Minimum wind flow of air directional drilling technology in soft-fragmentized coal seam[J]. Safety in Coal Mines，2021，52(7)：175−180.

[10] 郭盛强，苏中良，何庆宏，等. 碎软煤层穿层压裂的层段优选方法研究[J]. 煤矿安全，2018，49(11)：155−159.

GUO Shengqiang，SU Zhongliang，HE Qinghong，et al. Layer selection method for translayer fracturing of broken and soft coalbed[J]. Safety in Coal Mines，2018，49(11)：155−159.

[11] 狄朋毅，熊祖强，芦海广. 千米钻机氮气复合钻进工艺在碎软煤层的试验[J]. 山西焦煤科技，2019，43(5)：28−31.

DI Pengyi，XIONG Zuqiang，LU Haiguang. Experimental study on nitrogen composite drilling process of kilometer-deep drilling in broken soft coal seam[J]. Shanxi Coking Coal Science & Technology，2019，43(5)：28−31.

[12] 李泉新，石智军，田宏亮，等. 我国煤矿区钻探技术装备研究进展[J]. 煤田地质与勘探，2019，47(2)：1−6.

LI Quanxin，SHI Zhijun，TIAN Hongliang，et al. Progress in the research on drilling technology and equipment in coal mining areas of China[J]. Coal Geology & Exploration，2019，47(2)：1−6.

[13] 王建彬，金新，王力，等. 中风压空气钻进技术在平煤某矿的应用[J]. 探矿工程(岩土钻掘工程)，2011，38(11)：35−37.

WANG Jianbin，JIN Xin，WANG Li，et al. Application of medium pressure air drilling technology in Pingdingshan coalmine[J]. Exploration Engineering (Rock & Soil Drilling and Tunneling)，2011，38(11)：35−37.

[14] 殷新胜，刘建林，冀前辉. 松软煤层中风压空气钻进技术与装备[J]. 煤矿安全，2012，43(7)：63−65.

YIN Xinsheng，LIU Jianlin，JI Qianhui. Medium wind pressure air drilling technique and equipments in soft coal seam[J]. Safety in Coal Mines，2012，43(7)：63−65.

[15] 姚宁平，王毅，姚亚峰，等. 我国煤矿井下复杂地质条件下钻探技术与装备进展[J]. 煤田地质与勘探，2020，48(2)：1−7.

YAO Ningping，WANG Yi，YAO Yafeng，et al. Progress of drilling technologies and equipments for complicated geological conditions in underground coal mines in China[J]. Coal Geology & Exploration，2020，48(2)：1−7.

[16] 申瑞臣. 泡沫发生器结构设计综述[J]. 石油机械，1993，21(5)：52−55.

SHEN Ruichen. Summary of structural design of foam generator[J]. China Petroleum Machinery，1993，21(5)：52−55.

[17] 章志轩，颜廷超，鲁明春，等. 低压疏松砂岩气井泡沫发生装置的研发与应用[C]//2021IPPTC国际石油石化技术会议论文集. 北京，2021：635–645.

[18] 刘承婷，张维薇，刘钢，等. 螺旋挡板式泡沫发生器的设计及内部流动特性研究[J]. 数学的实践与认识，2018，48(8)：120−127.

LIU Chengting，ZHANG Weiwei，LIU Gang，et al. Design of spiral baffle foam generator and study on internal flow characteristics[J]. Mathematics in Practice and Theory，2018，48(8)：120−127.

[19] 刘宏生，杨莉，许关利，等. 一种可调孔隙介质的泡沫发生器：CN201236686Y[P]. 2009-05-13.

[20] 张维薇. 多级挡板扰流泡沫发生器流场分析及实验研究[D]. 大庆：东北石油大学，2019.

ZHANG Weiwei. Numerical study of gas-liquid flow and experimental study in foam generator with disturbing device of multi-baffle[D]. Daqing：Northeast Petroleum University，2019.

[21] 李家丞，栾伯川. 射流式泡沫发生器内部流场的数值模拟[J]. 辽宁化工，2017，46(9)：920−922.

LI Jiacheng，LUAN Baichuan. Numerical simulation of internal flow field in jet-type foam generator[J]. Liaoning Chemical Industry，2017，46(9)：920−922.

[22] 文虎，黄剑，赵炬，等. 基于FLUENT的气化灰渣灌浆输送特性模拟[J]. 煤炭技术，2023，42(9)：119−124.

WEN Hu，HUANG Jian，ZHAO Ju，et al. Simulation of gasification ash grouting transport characteristics based on FLUENT[J]. Coal Technology，2023，42(9)：119−124.

[23] 杨希培，邢玉强. 采动应力作用下煤岩渗流场演化规律数值模拟[J]. 煤矿安全，2024，55(4)：33−41.

YANG Xipei，XING Yuqiang. Numerical simulation of evolution law of coal seepage field under mining stress[J]. Safety in Coal Mines，2024，55(4)：33−41.

[24] 张志军，黄旭贝. 湍流环境下颗粒与气泡黏附过程的数值模拟研究[J]. 煤炭学报，2024，49(4)：2057−2066.

ZHANG Zhijun，HUANG Xubei. Numerical simulation of the attachment process of particles and bubbles in a turbulent environment[J]. Journal of China Coal Society，2024，49(4)：2057−2066.