吸附树脂真空变压吸附法处理丙酮气体研究

发布时间：2017-12-27 08:38

本文关键词：吸附树脂真空变压吸附法处理丙酮气体研究　出处：《南京大学》2016年硕士论文　论文类型：学位论文

【摘要】：吸附法由于去除效率高、工艺简单、可回收有机溶剂及一次投资成本低等优点,是当前国内外用于回收废气中挥发性有机物(VOCs)的主流技术。水蒸气变温吸附和真空变压吸附是吸附法处理VOCs最常用的两种工艺,相比水蒸气变温吸附工艺,真空变压吸附工艺可以对脱附下的水溶性VOCs直接冷凝回收,具有无二次污染、能耗低等优点。超高交联吸附树脂具有稳定的机械强度、可根据被吸附组分调控的孔结构、良好的吸附-脱附性能等优点,在吸附处理VOCs上逐渐成为研究热点。本文选用超高交联吸附树脂HCP-001作为吸附剂,以工业上常用的水溶性有机溶剂丙酮为研究对象,开展了超高交联吸附树脂变压吸附特性研究。主要的研究内容和结果如下：(1)采用柱吸附-脱附装置,研究了丙酮在超高交联吸附树脂HCP-001上的等温变压吸附特性。实验结果表明：丙酮在超高交联吸附树脂HCP-001上的吸附量,随着丙酮气体浓度的提高而增大,随着吸附温度升高而降低。真空度、脱附温度、吸附时丙酮浓度等是影响丙酮真空脱附效率的重要因素。真空度越高,脱附率越高,真空度为98kPa时脱附率比真空度90kPa增加25.3%;脱附温度越高越有利于丙酮脱附,脱附温度60℃时脱附率达到85.3%,相比脱附温度30℃时增加53.3%；吸附时丙酮浓度越高,脱附率越高,这可能是因为低浓度丙酮主要被吸附在微孔,而浓度较高的丙酮不仅在微孔内发生吸附,而且在中孔内也发生了吸附；由于微孔比中孔具有更大的吸附势,因而吸附在中孔内丙酮相比微孔内丙酮更易脱附,导致吸附高浓度丙酮的树脂比吸附低浓度丙酮具有更高脱附率;吸附-脱附两操作之间静置时间对脱附有一定的影响,静置时间越长脱附率越低,这主要是因为丙酮在超高交联吸附树脂上吸附,主要受孔内扩散控制,吸附穿透时并没有达到平衡状态,被吸附的丙酮分子继续向吸附作用势更强的微孔内吸附位点扩散,强的吸附作用力导致脱附率和脱附速率的下降。此外,还对比研究了氮气吹扫的脱附特性,吹扫气量越大、温度越高,脱附率和初始脱附速率越高;热氮气吹扫脱附率比真空脱附高,但脱附下的丙酮浓度较低,不利于后续的回收。(2)采用拟绝热吸附装置,通过检测超高交联吸附树脂HCP-001吸附、脱附丙酮过程中床层温度和出口浓度变化,研究丙酮在超高交联吸附树脂上的拟绝热变压吸附特性。实验结果表明：吸附时丙酮浓度越高,穿透时间越短,床层温升越高；真空脱附过程中,吸附时丙酮浓度越高,脱附率越低,这是由于吸附时丙酮浓度越高,脱附过程中床层温度降低越多,较低的床层温度导致了低脱附率；真空度越高,脱附率越高,脱附气浓度越高。此外,还比较研究了氮气吹扫的脱附特性,吹扫气量越大、吹扫气温度越高,脱附率越高,脱附率高于真空脱附效率;但是,相比于真空脱附方法,吹扫气脱附下的丙酮浓度较低,不利于后续的回收。(3)针对常规真空变压吸附工艺,开展了吹扫气辅助真空脱附和床层内置换热管变压吸附改进研究。实验结果表明：吹扫气辅助真空脱附可提高脱附效果,“真空+氮气间歇吹扫”、“先真空+后吹扫”和“先吹扫+后真空”的脱附率皆高于单一真空脱附,其中采用“真空+氮气间歇吹扫”进行脱附时,脱附气中丙酮浓度最高且脱附率最高,脱附率比只采用真空脱附增加28.91%。吸附床内置换热管对吸附和脱附效率都有提高,吸附时通入20℃的冷却水,可将床层最高温升降低3.8℃,而且增加了吸附树脂的穿透吸附能力,穿透时间延长37.4%；脱附时通入60℃的热水,提高了脱附气中丙酮的浓度,而且相比无加热脱附,脱附率提高约10%。
[Abstract]:Adsorption is a mainstream technology for recovering volatile organic compounds (VOCs) from waste gas at home and abroad due to its high removal efficiency, simple process, recyclable organic solvents and low investment cost. Steam temperature swing adsorption and vacuum pressure swing adsorption are two most commonly used VOCs processes for adsorption. Compared with steam temperature swing adsorption process, vacuum pressure swing adsorption process can directly recover condensed water soluble VOCs from desorption, and has the advantages of no two times pollution and low energy consumption. Super high crosslinked adsorption resin has stable mechanical strength and can be controlled according to the pore structure of adsorption components, and has good adsorption and desorption properties. It has gradually become a research hotspot in adsorption treatment of VOCs. In this paper, super high crosslinking adsorption resin HCP-001 was used as adsorbent, and the water soluble organic solvents acetone in industry as the research object, the pressure swing adsorption characteristics of super high crosslinked adsorption resin were studied. The main research contents and results are as follows: (1) the adsorption characteristics of acetone on the super high crosslinking adsorption resin HCP-001 were studied by column adsorption desorption device. The experimental results show that the adsorption amount of acetone on the super high crosslinking adsorption resin HCP-001 increases with the increase of acetone gas concentration, and decreases with the increase of adsorption temperature. The vacuum degree, the desorption temperature, the concentration of acetone and so on are the important factors that affect the efficiency of the acetone vacuum desorption. The higher the vacuum, the desorption rate is high, the vacuum degree of 98kPa desorption rate is 25.3% higher than the vacuum desorption temperature of 90kPa; more conducive to acetone desorption, desorption temperature of 60 DEG C when the desorption rate reached 85.3%, compared to the desorption temperature of 30 DEG C when the increase of 53.3%; when the concentration of acetone adsorption high desorption rate is high, it may be because of the low concentration of acetone was the main adsorption in micropores, and the higher concentration of acetone in the micropore adsorption occurs not only, but also in the hole also occurred due to micropore adsorption; adsorption potential is greater than the hole, the hole in the adsorption of acetone is more easily in the desorption phase than microporous resin adsorption of high concentration lead to acetone, acetone has a high rate of adsorption of low concentration acetone; adsorption desorption between the two operation time on the removal of a certain impact, the longer the static desorption rate is low, this is mainly because the acetone in the high-crosslinked Adsorption on resin is mainly controlled by pore diffusion, and the equilibrium state is not reached when adsorption is penetrating. The adsorbed acetone molecules continue to move towards the adsorption sites with stronger adsorption force, and strong adsorption force leads to the decrease of desorption rate and desorption rate. In addition, the desorption characteristics of nitrogen purging were compared. The higher the purging volume and the higher the temperature, the higher the desorption rate and the initial desorption rate. The purging desorption rate of hot nitrogen is higher than that of vacuum desorption, but the acetone concentration under desorption is low, which is not conducive to subsequent recovery. (2) the quasi adiabatic adsorption device, by detecting the hypercrosslinked resin HCP-001 adsorption, desorption of acetone of the bed temperature and outlet concentration, pseudo adiabatic pressure swing adsorption in the hypercrosslinked resin on acetone. The experimental results show that the adsorption of acetone concentration is high, the breakthrough time is shorter, the bed temperature rise high; vacuum desorption process, the adsorption of acetone concentration is higher, the lower the desorption rate, which is due to the adsorption of acetone concentration, desorption of the bed temperature decreased, the bed temperature is low leads to low desorption rate; the higher the vacuum, the desorption rate is higher, the higher the concentration of gas desorption. In addition, the desorption characteristics of nitrogen purging were also compared. The higher the purging gas volume and the higher the purging gas temperature, the higher the desorption rate, the higher the desorption rate than the vacuum desorption efficiency. However, compared with the vacuum desorption method, the acetone concentration under purge gas desorption is low, which is not conducive to subsequent recovery. (3) aiming at the conventional vacuum pressure swing adsorption process, the improvement of the vacuum desorption of blowing gas and the pressure swing adsorption of the inner heat transfer tube of the bed are carried out. The experimental results show that the purge gas assisted vacuum desorption can improve desorption effect, "vacuum intermittent + nitrogen purge" and "first vacuum + Post purge" and the "first purge + after vacuum desorption rate is higher than that of the vacuum desorption, which adopted the" vacuum batch + nitrogen purge "for desorption, removal of gas in the highest concentration of acetone and the removal of the highest rate, desorption rate than the vacuum desorption increased by 28.91%. The adsorption bed built-in heat pipe on the adsorption and desorption efficiency are improved, the cooling water adsorption into 20 DEG, 3.8 DEG C can be reduced or the bed temperature, but also increase the adsorption resin adsorption capacity, penetration time increased 37.4%; desorption by introducing 60 DEG C hot water, improve the concentration of deacetone gas, and compared with no heating desorption, desorption rate increased about 10%.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X701

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