硝镁法浓硝酸装置冷凝液的节能改造总结

Summary of energy-saving renovation of condensed fluid in concentrated nitric acid plant by magnesium nitrate method

针对某22万t/a浓硝酸装置闪蒸罐冷凝液处理原设计存在的问题,进行了节能改造。原设计中闪蒸罐底部冷凝液直接对地沟排放,造成了大量的冷凝液物料消耗及能量损失,产品生产成本增加,影响了企业的经济效益;此外,现场运行中还存在闪蒸的低压蒸汽带液的问题,影响低压蒸汽管网其他用户。针对上述问题,对浓硝酸装置的蒸汽冷凝液实施了二次闪蒸回收的改造措施。二次闪蒸出来的低低压蒸汽送至低低压蒸汽回收装置,产生的冷凝液优先供应稀硝装置除氧器作为补水使用,多余部分送至除盐水岗位进行制水。改造后,稀硝装置脱盐水、低压蒸汽消耗明显下降,浓硝装置副产冷凝液量568 kg/t,实现了装置的节能降耗,降低了生产成本,年增加效益200多万元。

The energy-saving renovation is carried out aiming at the problems existed in the original design of condensed fluid treatment of flash tank in a 220 kt /a concentrated nitric acid unit. In the original design, the condensed fluid from the bottom of flash tank is discharged to ditch, which causes a large quantity of loss to material and energy consumption of condensed fluid, increase of production cost, and decrease of economic benefit of enterprise. In addition, the low-pressure steam with condensing liquids has influ-ence on the other user in the low-pressure steam pipe net. Aiming at the mentioned problems, the reformation measures are implemen-ted ,that is secondary flashing and recycling steam condensate of concentrated nitric acid unit. The low-low-pressure steam generated from secondary flashing is sent to recovery unit of low-low-pressure steam, the condensed fluid is preferentially sent to deaerator of di-lute nitric acid unit used as supplementary water, and the remainder is sent to demineralized water device to produce demineralized wa-ter. After renovation, the consumption demineralized water and low-pressure steam decreases sharply, and the amount of byproduct condensed fluid is 568 kg/ t , which realizes energy saving and consumption reducing, and the benefit can increase more than 2 million yuan per year.