为解决梗丝气流干燥出口含水率波动大、合格率低等问题，通过对气流干燥过程分析，对出口含水率的控制模式进行了优化设计：①调整出口水分仪检测点位置，将出口水分仪检测点从干燥出口处调整到梗丝风送后电子秤处。②增设计量管，在风送工序出口的落料器上安装计量管。③优化PID控制程序，重新设置控制点延时时间以及各工序的数据反馈时间，将物料流量的步长值从2 kg/s提高到5 kg/s，保证了物料流量控制的准确性。结果表明：改进后梗丝气流干燥出口含水率为12.61%，能够满足卷烟工艺标准；出口含水率合格率由78.52%提高到99.40%；过程控制西格玛水平从2.86提高到4.07。改进后生产运行稳定，提高了气流干燥过程控制能力和成品梗丝品质。%To reduce the fluctuation of moisture content in cut stems out of the pneumatic dryer, the control system in the pneumatic dryer was optimized as following: 1) Relocating the testing point of moisture meter from the outlet to the electronic weigher next to pneumatic cut stem conveying. 2) Adding a metering tube to the feeding airlock at the outlet of pneumatic conveying. 3) Optimizing PID control program, resetting the delay time of control points and the data feedback from each processing step and increasing the step of tobacco flow from 2 to 5 kg/s to ensure accurate tobacco flow control. The results showed that after improvement, the moisture content in dried cut stems was 12.61%, which conformed to the technical standard; the qualified rate raised from 78.52% to 99.40%; and the sigma level of process control increased from 2.86 to 4.07. The equipment ran stably, the process control of pneumatic drying and the quality of dried cut stems were promoted.
展开▼
