低浓度VOCs废气转轮吸附浓缩装置设计毕业论文

 2021-04-28 11:04

摘 要

随着我国经济的高速发展,挥发性有机污染物(Volatile Organic Compounds,VOCs)的排放量因为治理不善和一些化工企业不重视环保,加剧了空气污染。在众多的 VOCs处理技术中,吸附技术因为其工艺成熟、去除率高等诸多优点成为主流处理技术。作为一种新型高效率吸附装置的,转轮吸附浓缩装置的特征在于,将吸附工段和解吸工段都集中于连续操作的一个装置上,通过转轮的旋转,吸附剂周期性吸附和脱附以实现VOCs的废气的净化。在本设计中,温度为25 ℃,流量为100000 m3/h通过转轮吸附VOCs混合物浓度为 116 mg/m3的甲苯,135 mg/m3乙酸乙酯,200 mg/m3乙醇,120 mg/m3环己烷为主要成分废气处理对象,在设计浓缩比为9的条件下,基于自主开发的吸附效率为80%的高性能复合吸附材料及其通过吸附实验得到的实验数据,从而通过这些数据和相关计算设计出一套使用转轮吸附装置,主要设计结果为:转轮转速ω=2 r/h,再生风温度为100 ℃,吸附剂体积为1.26 m 3,转轮盘面采用24分割,吸附区占7/8,脱附区占1/8,每个分割区采用双层堆叠吸附单元的方式。该装置与传统的固定床吸附装置相比具有运行稳定、内部阻力小、,能量损失小、结构紧凑、整体设备占地面积小等诸多优点。吸附效果稳定,可以有效吸附吸附效率可以达到80%,经过吸附脱附后C甲苯=0.94 g/Nm3,C乙酸乙酯=1.10 g/Nm3,C乙醇=1.63 g/Nm3,C环己烷=0.89 g/m3,排放气C甲苯=23.20 mg/m3,C乙酸乙酯=27.00 mg/m3,C乙醇=40.00 mg/m3,C环己烷=24.00 mg/m3,使其浓度大大降低可以有效降低VOCs对环境污染。

关键词:立式转轮;转轮吸附;有机废气;

Design of adsorption and concentration device for low concentration vocs waste Gas Runner

ABSTRACT

With the rapid development of China's economy, the emission of volatile organic pollutants (VOCs) has increased air pollution because of poor treatment and some chemical enterprises do not pay attention to environmental protection. Among many VOCs treatment technologies, adsorption technology has become the mainstream treatment technology because of its mature technology and high removal rate. As a new type of high efficiency adsorption device, the rotary adsorption concentration device is characterized by that both the adsorption section and the desorption section are concentrated on a continuous operation device. The adsorbent periodically adsorbs and takes off with the rotation of the channel. Cooling is added to purify VOCs. In this design, the temperature is 25 ℃and the flow rate is 100000 m3/h, which is adsorbed by the runner. The toluene exhaust gas with toluene concentration of 200 mg/m3 is treated as the object. Under the condition of design concentration ratio of 9, a set of runner adsorption device is designed based on the self-developed high performance composite adsorption material with 80% adsorption efficiency and experimental data obtained from adsorption experiments. The main design results are as follows: runner speed=2 r/h, regeneration air temperature 100 ℃. The volume of adsorbent is 1.26 m3. The runner disk is divided into 24 parts, the adsorption area accounts for 7/8, and the desorption area accounts for 1/8. Each partition is made up of two layers of stacked adsorption units. Compared with the traditional fixed bed adsorption device, the device has many advantages, such as stable operation, small internal resistance, small energy loss, compact structure and small occupied area of the whole equipment. The adsorption effect is stable, and the effective adsorption efficiency can reach 80%. After adsorption and desorption, the concentration of concentrated gas is 402.04 mg/Nm3 and the concentration of toluene is reduced to 40 mg/m3, which can effectively reduce VOCs pollution to the environment.

Key words:vertical runner; Wheel adsorption; Organic waste gas;

目 录

摘 要 1

ABSTRACT 2

前 言 6

1. VOCs的介绍 7

1.1 工业源 VOCs的特点 7

1.1.1 种类多且性质差异大 7

1.1.2 同时含有多种类型的污染物 7

1.2 VOCs 治理技术 7

1.2.1 回收技术 8

1.2.2 销毁技术 9

2. 吸附原理 12

2.1 传质作用机理 12

2.1.1 吸附平衡 12

2.1.2 吸附速率 13

2.1.3 吸附阻力 13

2.2吸附剂 13

1、活性炭 14

2、硅胶 14

3、活性氧化铝 14

4、沸石分子筛 14

3. 吸附工艺及设备 15

3.1 固定床吸附工艺 15

3.2 移动床吸附工艺 15

3.3 流化床吸附工艺 15

3.4 吸附剂再生 16

4 设计意义及内容 17

4.1 设计意义 17

4.2 设计内容 17

结 论 29

致 谢 30

参考文献 31

前 言

VOCs 污染现状

VOCs是易挥发性有机物的英文简称。在我国,VOCs定义为指20 ℃下饱和蒸汽压大于133.32 Pa、在760 mmHh的气压下沸点为50~260 ℃一类容易挥发的有机化合物,或者在1.013 kPa,298.15 K任何容易挥发的有机固体或者液体。VOCs是一大类有机化合物的统称,包括了大部分有机化合物门类比如烷基类、苯类、羰基化合物、酯类化合物等。常见的有苯、甲苯、甲醛等容易挥发的有机物,因为它具有很强的毒性而且对人体的肺部和其他器官有很大的刺激性,对人体健康危害大[1-2]。除此以外,VOCs有比较大的处理难度,容易造成污染。据环保部门,烟雾,PM2.5,O3统计,酸雨等气象灾害与挥发性有机物[3]的排放密切相关。随着中国经济的快速发展,挥发性有机物的污染已成为大气复合污染的重点城市群,并在中国的主要工业区的重要前体之一。由相关统计资料表明,在中国,大部分的VOCs排放来源于石油化工生产以及其他相关产业 [4]。近年来,工业生产造成的VOCs排放量持续增长,而挥发性有机化合物的年均增长率更是高达11%-12%。由此可见,对工业生产过程中产生的VOCs的严格控制和对工业废气中的VOCs进行终端净化,是降低大气中 VOCs含量的重要手段。随着挥发性有机化合物对环境到现在越来越多的负面影响,从2010年开始,国家先后出台了十几个国家的政策和相关的挥发性有机化合物的严格防范和控制法律和法规。有些省市陆续推出污染物排放挥发性有机化合物。我国在1997年1月1日国家出台的《中华人民共和国国家标准大气污染物综合排放标准》(GB16297-1996)规定了苯、甲苯、二甲苯、氯乙烯、二氯甲烷等 VOCs 排放许可标准。国家地方两手抓,从而实现综合治理,改善空气质量的目的。

  1. VOCs的介绍

1.1 工业源 VOCs的特点

VOCs根据主要官能团可分为 8 类[5] ,如表 1.1 所示。

您需要先支付 80元 才能查看全部内容!立即支付

课题毕业论文、开题报告、任务书、外文翻译、程序设计、图纸设计等资料可联系客服协助查找,优先添加企业微信。