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1.
对平均孔径200 nm的氧化锆陶瓷膜进行疏水改性与表征,并将其组装制成疏水性单管陶瓷膜接触器,采用清水作为低成本吸收液,开展了陶瓷膜接触器在废气脱硫方面应用的研究。比较了亲、疏水陶瓷膜接触器的传质性能,考察了进气流量、吸收液流量、进气浓度和吸收液温度等因素对SO2脱除率和传质速率的影响,并对陶瓷膜接触器进行了长期稳定性测试。研究表明,疏水改性只改变陶瓷膜的表面性质(接触角达到132°),对形貌结构影响较小;与未改性的陶瓷膜相比具有更高的脱硫效率和总传质系数。SO2的脱除率和传质速率随吸收液流量的增加均增加;SO2的脱除率随进气流量和进气浓度的增加而降低,但传质速率增加;吸收液温度的升高不利于SO2的吸收;原料气中的CO2对SO2的脱除率影响较小。与传统的填料塔相比,陶瓷膜接触器具有更小的传质单元高度(HTU)值。陶瓷膜接触器脱硫效率高,可稳定操作,在废气脱硫方面具有良好的应用前景。 相似文献
2.
利用聚丙烯中空纤维双层曝气式膜接触器,对膜曝气-膜吸收耦合式海水烟气脱硫过程开展实验研究,考察了烟气流量、海水流量、海水pH以及曝气量等因素对烟气脱硫参数的影响。结果表明,曝气式膜吸收过程具有更高的脱硫效率和传质性能,相较于非曝气过程,SO2吸收率可提高12.4%。提高烟气流量,使SO2吸收率降低,总传质系数先增大再减小;提高吸收剂流量、pH和曝气量,SO2吸收率和总传质系数均会提高,海水pH较高条件下加入曝气更能有效加强吸收效果;烟气中SO2的吸收通量均随海水pH和曝气量的增加而增加。扫描电镜及接触角测量显示在使用一个月后的膜丝仍具有较高的疏水性能和使用性能。 相似文献
3.
采用臭氧氧化结合湿法喷淋硫代硫酸钠溶液的方法开展模拟烟气同时脱硫脱硝实验研究。结果表明,采用臭氧氧化结合Na2S2O3-NaOH溶液湿法喷淋可以实现NOx和SO2协同脱除:在O3/NO摩尔比为1.1~1.2时,溶液中Na2S2O3浓度的增加会提高系统的NOx脱除效率,烟气中SO2的存在会促进NOx的脱除,当SO2浓度为1030 mg·m-3、2.0%Na2S2O3溶液作为喷淋液时可实现较高的SO2脱除效率,同时NOx脱除效率可达70%以上;喷淋液pH在2.5~9范围内变化时提高浆液pH有利于NOx的脱除,当pH 9时脱硝效率可达75%。180 min连续同时脱硫脱硝实验结果表明,硫代硫酸钠可有效促进NOx的脱除,并实现SO2较高的脱除效率,同时可实现系统同时脱硫脱硝连续稳定运行,喷淋吸收后烟气中NOx的主要转化产物为NO2-, 该方法作为一种有效的同时脱硫脱硝技术,具有一定的工业应用推广前景。 相似文献
4.
在小型紫外光-鼓泡床反应器中,对UV/H2O2氧化联合Ca(OH)2吸收同时脱除燃煤烟气中NO与SO2的主要影响因素[H2O2浓度、紫外光辐射强度、Ca(OH)2浓度、NO浓度、溶液温度、烟气流量以及SO2浓度]进行了考察。采用烟气分析仪和离子色谱仪分别对尾气中的NO2和液相阴离子作了检测分析。结果显示:在本文所有实验条件下,SO2均能实现完全脱除。随着H2O2浓度、紫外光辐射强度和Ca(OH)2浓度的增加,NO的脱除效率均呈现先大幅度增加后轻微变化的趋势。NO脱除效率随烟气流量和NO浓度的增加均有大幅度下降。随着溶液温度和SO2浓度的增加,NO脱除效率仅有微小的下降。离子色谱分析表明,反应产物主要是SO42-和NO3-,同时有少量的NO2-产生。尾气中未能检测到有害气体NO2。 相似文献
5.
《化工学报》2017,(6)
对平均孔径200 nm的氧化锆陶瓷膜进行疏水改性与表征,并将其组装制成疏水性单管陶瓷膜接触器,采用清水作为低成本吸收液,开展了陶瓷膜接触器在废气脱硫方面应用的研究。比较了亲、疏水陶瓷膜接触器的传质性能,考察了进气流量、吸收液流量、进气浓度和吸收液温度等因素对SO_2脱除率和传质速率的影响,并对陶瓷膜接触器进行了长期稳定性测试。研究表明,疏水改性只改变陶瓷膜的表面性质(接触角达到132°),对形貌结构影响较小;与未改性的陶瓷膜相比具有更高的脱硫效率和总传质系数。SO_2的脱除率和传质速率随吸收液流量的增加均增加;SO_2的脱除率随进气流量和进气浓度的增加而降低,但传质速率增加;吸收液温度的升高不利于SO_2的吸收;原料气中的CO_2对SO_2的脱除率影响较小。与传统的填料塔相比,陶瓷膜接触器具有更小的传质单元高度(HTU)值。陶瓷膜接触器脱硫效率高,可稳定操作,在废气脱硫方面具有良好的应用前景。 相似文献
6.
为减少船舶柴油机烟气中NO的排放,将光催化技术与紫外/NaHSO3高级还原技术联合还原脱除模拟烟气中NO。制备了Ag/TiO2-x/泡沫陶瓷光催化剂,利用自制的光催化海水喷淋反应器考察了温度、液气比、NaHSO3浓度、空速、NO浓度对脱硝率的影响。结果表明,随着温度的升高,脱硝率提高;液气比为3~6 L/m3时,脱硝率变化较小;随着NaHSO3浓度的增大,脱硝率先升后降;空速和NO浓度增大都不利于脱硝。光催化联合海水NaHSO3能还原脱除NO,NO质量浓度为1 000 mg/m3时,脱硝率可达66.6%,N2选择性为67.54%,NH+4选择性为13.16%。 相似文献
7.
在CO2化学吸收法工艺中,采用富液分流工艺,利用在贫富液换热器前分流的冷富CO2吸收剂溶液回收再生塔顶排出的热再生气(一般为CO2和水蒸气混合气)的余热,有助于降低CO2再生热耗。本文在乙醇胺(MEA)基富液分流化学吸收工艺中,以纳米级多孔亲水陶瓷膜作为分流冷富液和热再生气之间的换热介质,利用水的热质耦合传递强化余热的回收性能。以余热回收通量为指标,探讨了分流的MEA富液流量、温度、质量分数、CO2负荷和热再生气流量及再生气中水蒸气摩尔分数对陶瓷膜热回收性能的影响,并对比了不同分离层孔径陶瓷膜的余热回收性能。结果显示,陶瓷膜的余热回收性能随MEA富液流量的增加而增加,但却随富液温度的升高而大幅下降。同时,随着气体流量和再生气中水蒸气摩尔分数的增大,热回收通量均会增大。由水传质所引发的对流换热对热回收通量具有促进作用,可占总热回收量的10%左右。由于CMHE-10陶瓷膜的分离层孔径与孔隙率均大于CMHE-4陶瓷膜,因而其水传质通量大于CMHE-4陶瓷膜。但CMHE-10陶瓷膜的有效热导率却低于CMHE-4陶瓷膜,因而热回收过程中其水蒸气的冷凝总量要小,导致其热回收性能低于CMHE-4陶瓷膜。 相似文献
8.
为强化二氧化碳的吸收过程,采用一类旋流逆向气液多级接触的方式,以NaOH溶液为吸收剂,研究其与大跨度浓度CO2(2.5%~15%)接触反应的传质性能。分别探讨了吸收剂浓度、吸收剂流量、烟气CO2浓度、烟气流量及反应温度对气相总体积传质系数(Kga)的定量影响。结果表明,在实验条件下,其Kga可达(4.53×10-5)~(9.22×10-5)kmol·m-3·s-1·kPa-1。与双级直流喷雾和单级旋流喷雾相比,旋流逆向气液多级接触能够有效强化大跨度浓度CO2的吸收过程。Kga随吸收剂浓度、流量和反应温度的增加而增加,随CO2浓度增加呈现先增加后减小(CO2浓度大于5%)的非线性关系,随气体流量增加先增加后趋于稳定。 相似文献
9.
在一种新型高效的气液传质设备--水力喷射-空气旋流器(WSA)中,以Ca(OH)2料浆为吸收剂进行了模拟烟气湿法脱硫的实验研究。结果表明:脱硫率随进口气速增加而增加;随液体喷射速度增加先增加,增加到一定程度后几乎不变;随烟气中SO2的进口浓度增加而减小,存在一适宜的Ca(OH)2浓度和回流比。在气体流量24~72 m3·h-1、循环液体量0.4~0.8 m3·h-1、料浆中Ca(OH)2浓度7500 g·m-3时,对SO2浓度为1891~6373 mg·m-3的烟气进行湿法脱硫,脱硫率达88.9%~97.7%,且WSA的旋流气体和喷射液体在湿法脱硫中具有自清洁能力,未发现内部结垢和喷孔堵塞现象。总体积传质系数KGa、有效相界面积a均随进口气速uG增大而增大,而总传质系数KG随uG增加变化较小;当液体喷射速度 uL≤0.26 m·s-1时,KGa和KG随uL增加快速增大,之后增加缓慢,而a随uL几乎线性增加,KGa和KG随吸收剂中Ca(OH)2浓度cL增加有一最大值。结合实验数据拟合得到了相关的经验公式,这些关联式能较好地预测WSA的湿法脱硫传质性能。气体旋流场强度对总体积传质系数KGa和有效相界面积a起支配作用,脱硫传质过程同时受气膜和液膜阻力控制,但以液膜控制为主。 相似文献
10.
利用湿壁塔实验台对燃煤烟气中SO2对氨水溶液[1%~7%(质量)]吸收CO2的影响进行了实验研究,具体分析了不同反应温度(20~80℃)和CO2体积分数(5%~20%)条件下,CO2传质通量及传质系数随SO2浓度和SO2负载量的变化规律。结果表明, SO2浓度由0增至11428 mg·m-3,CO2传质通量及传质系数均有一半左右降幅,而SO2负载量[0.1~0.4 mol SO2·(mol NH3)-1]的增加,同样导致CO2传质通量及传质系数明显减小。氨水浓度及反应温度增加可有效提高CO2传质通量和传质系数,相对降低SO2对CO2传质的影响。CO2浓度的增加可明显提高其传质通量,但是CO2的传质系数有所降低。 相似文献
11.
中空纤维膜吸收烟气中CO2是一种清洁、高效、最具潜力的脱碳技术方法之一。本文建立了一个二维的中空纤维膜接触器平行逆流吸收混合气中CO2的非润湿模型。考虑轴向和径向扩散,模拟了EEA、EDA和PZ 3种吸收剂在不同操作条件下对CO2的脱除效果和传质性能。结果表明:脱碳性能从大到小为PZ>EDA>EEA;气相参数对脱碳和传质的影响比液相参数更显著;提高气体流速、CO2浓度和气温,脱碳率均会下降;提高液速、吸收剂浓度和液温,脱碳率均增大,而传质速率只有在提高气温时会下降,其他参数的升高均会使其增大;应采用适当的液相参数,防止操作参数过高带来的不利影响。 相似文献
12.
Theoretical and Experimental Studies on Acetylene Absorption in a Polytetrafluoroethylene Hollow‐Fiber Membrane Contactor
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The separation of acetylene from a gas mixture was investigated using a polytetrafluoroethylene hollow‐fiber membrane contactor and 1‐methyl‐2‐pyrrolidinone as absorbent. The effects of the gas velocity, the liquid velocity, the feed gas concentration, and the module length on the acetylene mass transfer were investigated. The results showed that the acetylene mass transfer flux increased with increasing liquid velocity, gas velocity, and feed gas concentration, but decreased with increasing membrane module length. A mathematical model was used to predict the wetting extent of the membrane and the mass transfer resistance in the acetylene mass transfer process. The wetting extent of the membrane was found to increase with increasing liquid velocity and to be effectively restrained with increasing gas velocity. The liquid phase resistance and the wetted‐membrane phase resistance controlled the acetylene mass transfer in the acetylene absorption process. The acetylene absorption efficiency was maintained at 90 % for 114 h of the C2H2 membrane absorption–thermal desorption cycle process. 相似文献
13.
N,N-二甲基乙醇胺(DMEA)是一种很有前途的吸收剂,具有较快的反应速率和较高的CO2捕集能力。在本研究中,DMEA作为一种新型吸收剂被应用于中空纤维膜接触器,用于从CO2/CH4气体混合物中分离CO2。通过建立二维稳态数学模型,模拟了MEA、DEA、MDEA和DMEA四种吸收剂在不同操作条件下对CO2吸收性能的影响。结果表明,脱碳性能大小为MEA>DMEA>DEA>MDEA;气相参数对脱碳率的影响比液相参数更显著;提高气体流速和CO2浓度,脱碳率均会下降;提高液速和吸收剂浓度,脱碳率均增大,适当提高吸收剂流速和吸收剂浓度可以提高CO2去除效率。此外,CO2吸收通量将随着气体速度的增加而增加,随着液相中CO2负荷的增加而减少。最后,通过两种影响因素共同作用确定了膜接触器分离酸性气体的最佳操作条件。因此,膜吸收法在天然气脱碳方面有良好的潜力。 相似文献
14.
A process of simultaneous desulfurization and denitrification of flue gas was conducted in this study. The flue gas containing 200 mg·m-3 NO, 1000-4000 mg·m-3 SO2, 3%-9% O2, and 10%-20% CO2 was first oxidized by O3 and then absorbed by ammonia in a bubbling reactor. Increasing the ammonia concentration or the SO2 content in flue gas can promote the absorption of NOX and extend the effective absorption time. On the contrary, both increasing the absorbent temperature or the O2 content shorten the effective absorption time of NOX. The change of solution pH had substantial influence on NOX absorption. In the presence of CO2, the NOX removal efficiency reached 89.2% when the absorbent temperature was raised to 60 °C, and the effective absorption time can be maintained for 8 h, which attribute to the buffering effect in the absorbent. Besides, both the addition of Na2S2O3 and urea can promote the NOX removal efficiency when the absorbent temperature is 25 °C, and the addition of Na2S2O3 had achieved better results. The advantage of adding Na2S2O3 became less evident at higher absorbent temperature and coexistence of CO2. In all experiments, SO2 removal efficiency was always above 99%, and it was basically not affected by the above factors. 相似文献
15.
Xingyin Gao Minghui Qiu Kaiyun Fu Peng Xu Xiangli Kong Xianfu Chen Yiqun Fan 《中国化学工程学报》2018,26(10):2139-2147
Hydrophilic ceramic membranes would be potential candidates for membrane gas absorption if they could be applied to appropriate separation processes. This study highlights a novel concept for the practical implementation of SO2 absorption in hydrophilic ceramic membrane that exhibits outstanding thermal and mechanical stabilities. With this aim, we investigated experimentally the performance of SO2 absorption into aqueous sodium hydroxide (NaOH) solution in a hydrophilic alumina (Al2O3) membrane contactor in terms of SO2 removal efficiency and SO2 mass transfer flux, and compared the performance with that in a hydrophobic one. A series of experiments were performed at various conditions over a NaOH concentration range of 0-1.0 mol·L-1, a liquid flow rate range of 30-180 ml·min-1, a gas flow rate range of 120-1000 ml·min-1, an inlet SO2 concentration range of 400-2000 μl·L-1, and a temperature range of 10-35℃. It was found that the hydrophilic membrane was more competitive when using a NaOH concentration higher than 0.2 mol·L-1. Furthermore, it can be inferred that the hydrophilic α-Al2O3 membrane exhibited exceptional long-term stability under 480 h continuous operation. 相似文献
16.
在传统的除雾型旋风分离器基础上进行改进,使其同时具备液相射流、气液吸收反应以及气液分离功能,并将这一新型旋风分离器用于烟气脱硫实验。实验中气相为含SO2烟气,液相为NaOH或Na2CO3碱液吸收剂,通过调节吸收剂浓度、烟气含硫浓度、烟气喷射速度、吸收剂喷射速度、吸收剂固含率等参数得到其相应脱硫率的变化。实验研究表明:脱硫率随吸收剂浓度的增加先增加,达到一定浓度后脱硫率几乎不变;脱硫率随SO2进口浓度的升高而下降;随进口气速的增大,脱硫率也一定程度增大;随液体喷射速度的增加脱硫率先增大,增大到一定程度后脱硫率趋于不变;NaOH作为吸收剂所得最佳脱硫率可达85%,Na2CO3作为吸收剂,最佳脱硫率可达77%;当其他参数一定时,加入一定量的CaCO3固体微粒,可以提高脱硫效率1%~2%。该液相射流吸收耦合气相旋流分离装置不仅脱硫效率高,而且脱硫剂损失少,投资成本与运行维护费用均低于相同处理量的烟气脱硫塔,具有良好的应用前景。 相似文献
17.
Hyun-Hee Park Chun-Won Lim Hang-Dai Jo Won-Kil Choi Hyung-Keun Lee 《Korean Journal of Chemical Engineering》2007,24(4):693-697
In this study, removal of SO2 from gas stream was carried out by using microporous polyvinylidene fluoride (PVDF) asymmetric hollow fiber membrane modules
as gas-liquid contactor. The asymmetric hollow fiber membranes used in this study were prepared polyvinylidene fluoride by
a wet phase inversion method. Water was used as an internal coagulant and external coagulation bath for all spinning runs.
An aqueous solution containing 0.02 M NaOH was used as the absorbent. This study attempts to assess the influence of PEG additive,
absorbent flow rate, SO2 concentration, gas flow rate and gas flow direction on the SO2 removal efficiency and overall mass transfer coefficient. The effect of liquid flow rate on SO2 removal efficiency shows that at very low liquid flow rate, the NaOH available at the membrane surface for reacting with
SO2 is limited due to the liquid phase resistance. As liquid flow rate is above the minimum flow rate which overcomes the liquid
phase resistance, the SO2 absorption rate is controlled by resistance in the gas phase and the membrane. The SO2 absorption rate with inlet SO2 concentration was sharply increased by using hollow fiber membranes compared to a conventional wetted wall column because
the former has higher gas liquid contacting area than the latter. The mass transfer coefficient is independent of pressure.
When the gas mixture was fed in the shell side, the removal efficiency of SO2 declined because of channeling problems on the shell side. Also, the addition of PEG in polymer dopes increased SO2 removal efficiency.
This work was presented at the 6
th
Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006. 相似文献