中浓纸浆泵运行性能试验研究

中浓纸浆泵是中浓输送环节的核心设备,其运行性能直接影响着输送系统的效率。为了研究不同运行条件对中浓纸浆泵运行特点和性能的影响,设计一种基于声纳流量测试系统的中浓纸浆泵性能试验台。研究分析了纸浆浓度(质量分数)为7.52%,9.3%,12.1%,转速为960 r/min,1 140 r/min,1 500 r/min和不同排气抽吸真空度时,泵的扬程、效率、出口含气率及最大极限流量变化特征。试验结果表明:随着纸浆浓度的增加,同一流量下扬程、效率逐渐下降。真空度对泵的性能特性有显著的影响,在不抽真空条件下,中浓纸浆泵可实现7.52%浓度纸浆的输送,但随着流量的增加,扬程、效率明显下降;随着抽吸真空度的增大,扬程逐渐升高,且存在一个最佳真空度值使得泵效率最高,泵出口纸浆的含气率逐渐降低。扬程随转速的增加而升高,泵出口纸浆的含气率降低;所需真空度随转速的增加而减小,表明提高泵转速有利于纸浆中气液的分离从而降低所需的真空度值。泵出口纸浆中含气率随着纸浆浓度的增加而升高,同时所需的抽吸真空度也迅速增加。最大流量极限值随着纸浆浓度的增加而减小,随转速的增加而增加。

Experimental Study on Operation Performance of Medium Consistency Pump

Medium consistency pump (MC pump) is the core equipment of medium consistency pulp transportation,and the efficiency of delivery system is directly determined by pump performance.In order to investigate the operation and performance characteristics of MC pump in different conditions,a MC pump test bed is established using sonar flowmeter and monitoring system.The head,efficiency,gas fraction and max flow rate are studied with pulp concentration 7.52％,9.3％,12.1％,speed 960 r/rain,1140 r/min,1 500 r/min and different degas vacuum degree at vacuum housing.The results show that at constant flow rate,pump head and efficiency decrease with increase of pulp concentration.Vacuum degree has significant effect on pump performance.MC pump can pump concentration 7.52％ pulp without vacuum,but pump head and efficiency decrease obviously with flow rate increasing.With vacuum degree increasing pump head increases,and gas fraction decrease at pump outlet.Head increases with rotation speed increasing,but gas fraction of pulp decreases at pump outlet.Vacuum degree decreases with rotation speed increasing,so enhancing pump speed can improve gas-liquid separation.Gas fraction and degas vacuum degree increase with concentration increasing.The max flow rate decreases with increase of concentration and increases with rotation speed increasing.