Application of sampling method based on negative pressure pneumatic conveying in soft coal seam

作者：Zhang Hongtu; Wei Jianping; Wang Yungang; Wen Zhihui; Yao Banghua

来源：International Journal of Heat and Technology, 2016, 34(3): 473-478.

DOI：10.18280/ijht.340317

• Drilling velocities
• Inner diameters
• Multi-phase theory
• Negative pressures
• Particle breakage
• Pneumatic conveying
• Positive pressure
• Sampling devices

Accurately determining coalbed gas content is difficult using the existing sampling methods in China. In this paper, the drawbacks of the sampling method based on positive pressure pneumatic conveying were analyzed. The sampling method based on negative pressure pneumatic conveying was presented aiming at increasing the coal sampling purity. Furthermore, the two key parameters of power device used during the process were determined using the multi-phase theory. Then, on-site tests were carried out to test the feasibility of the application of the sampling method based on negative pressure pneumatic in the soft coal seam of the Xin'an Coal mine by the self-developed sampling device. The result showed that the effect of drilling pipe rotation on the coal along the hole and poor stability of the hole in the soft coal seam led to low coal sampling purity with positive pressure pneumatic in the sampling method. The sampling method based on negative pressure pneumatic avoided the drawback of the sampling method based on positive pressure with higher coal sampling purity and shorter time consumption. The coal sampling with a length of 50m hole can be achieved within 0.5 min by the negative pressure pneumatic conveying sampling.

• 出版日期2016
• 单位Polytechnic university