过程工业尾气封闭循环原理与应用(Ⅰ):湿法磷酸  

Principles and application of enclosed exhausts cycling for process industry(Ⅰ):Wet process phosphoric acid

作　　者：李季[1] 彭玉凤 朱家骅[1] LI Ji;PENG Yufeng;ZHU Jiahua(School of Chemical Engineering,Sichuan University,Chengdu 610065,Sichuan,China)

机构地区：[1]四川大学化学工程学院,四川成都610065

出　　处：《化工学报》2021年第10期5257-5264,共8页CIESC Journal

基　　金：国家科技支撑计划项目(2013BAC12B01)。

摘　　要：基于Gibbs自由能原理,提出过程工业环境污染治理与产品加工过程相统一的广义生产系统及其自由能衡算方法,以污染物排放对应的自由能耗散与产品加工必需的有效自由能耗之比(自由能耗散比,RFED)表征环境污染的热力学代价,通过模型分析阐明过程工业尾气封闭循环是具有热力学普遍意义的尾气治理技术路线。以湿法磷酸现行尾气达标排放工艺为例,模型分析指出其自由能耗散比为2.54,即尾气污染物排放自由能耗散超过产品加工过程必需的有效自由能耗1.54倍,这是诸多滥用空气为热/质载体的末端排放工艺过程共同特征,亟需采用尾气封闭循环予以改善,亟待发展基于低品位热/质分离回收的尾气净化关键技术、以减排/增收效果强化尾气封闭循环的经济性。本文根据针对湿法磷酸尾气封闭循环取得的一系列单元技术开发成果及其应用前景进行初步报道,以期引起更多共鸣。Based on Gibbs free energy theory,a generalized production system and its free energy balance method that unify the environmental pollution control of the process industry and the product processing process are proposed.The thermodynamic cost of environmental pollution is characterized by the ratio of free energy dissipation(RFED)for pollutant emission-diffusion to free energy consumption necessary for product manufacturing.Through model analysis,it is clarified that enclosed exhausts cycling is a technical route of exhausts treatment with general thermodynamic significance.Taking the current standard of air pollutants emission for wet process phosphoric acid(WPA)industry as an example,the model calculation reveals the RFED value is 2.54,which means the free energy dissipation for exhaust pollutant emission is 1.54 times more than the effective free energy consumption for products.This is the common situation in end-of-pipe treatment processes which abuse air as heat and mass carrier,which is urgent to improve by implementing enclosed exhausts cycling process and developing corresponding key technology of exhaust purification emphasized on lower grade heat and mass separation and recovery,in order to strengthen the economy of enclosed exhausts cycling with the profit increase brought by emission reduction.Therefore,some promising achievements,obtained from a series of unit operation technology R&D of enclosed exhausts cycling for WPA,are preliminarily reported in this paper for arousing more response in this field.

关 键 词：过程系统 集成 污染控制 废物处理 循环利用 

分 类 号：TQ021.4[化学工程] X78[环境科学与工程—环境工程]