膜吸收法浓海水烟气脱硫试验研究

采用疏水性聚丙烯中空纤维膜制成膜接触器,以海水循环冷却系统排放的浓海水和与其pH值相同的原海水分别作为吸收液.考察吸收液流量、烟气流量、烟气浓度、气液相压力差等因素对脱硫率的影响.结果表明:与原海水作吸收剂相比,浓海水吸收SO2缓冲能力更大.脱硫效率更高.在操作方式相同,吸收液流量为10 L/h,烟气流量1 000 L/h的条件下,浓海水的脱硫率是原海水的2倍.在高盐度、高碱度、高浊度的浓海水介质条件下,膜接触器性能稳定,具备潜在工业化应用前景.     

气-液膜接触器结构优化及其传质性能研究

以海水作为吸收剂,采用模拟烟气,对气-液膜接触器进行传质性能评价试验,考察其工艺结构参数、气液介质流动速率及方式、气液压差、烟气SO2浓度等因素对传质系数、脱硫率及膜效用的影响.试验表明,在气相压力较低情况下,气液流速、气液压差对总气相传质系数影响明显,而烟气SO2浓度的影响可忽略不计.适当提高膜接触器的填充密度,增加膜吸收级数,采用错流模式的气液流动方式,均可改善烟气流场分布,增大有效传质面积,提高膜效用.与传统吸收塔相比,新型膜气体吸收装置的气液两相独立控制,可灵活应对烟气浓度变化对脱硫稳定性的影响,同时具有低气阻、耐污染、规模可线性放大等优点,工业化应用前景广阔.     

膜吸收法烟气同时脱硫脱硝试验研究

采用自行研制的新型错流式气-液膜接触器,以NaClO2海水溶液为吸收液,分别以NaHCO3/Ca(OH)2/Ca(ClO)2为添加剂,对电厂燃煤烟气开展膜吸收法烟气同时脱硫脱硝现场试验研究.考察了吸收液流量、浓度、活化时间、初始pH以及烟气流量、SO2浓度等因素对脱硫脱硝效果的影响.试验表明:增大吸收液流量和浓度,NOx和SO2脱除率升高;延长吸收液活化时间,增大烟气流量,脱硫脱硝率略有降低;吸收液初始pH升高,脱硫率几乎不变,而脱硝率却略有降低;随着SO2浓度增大,脱硝率出现极值点;另外,添加剂NaHCO3/Ca(OH)2/Ca(ClO)2对NaClO2氧化吸收NOx和SO2均有增强作用.采用膜气体吸收技术,可实现烟气同时脱硫脱硝,具有一定应用潜力.     

膜吸收法海水脱硫研究

实验采用疏水性聚丙烯中空纤维膜组件为膜接触器,以清水、海水以及与海水相同pH值的NaOH溶液作吸收液,比较了3种不同的吸收液对SO2与空气混合气体的脱硫效果.研究了气液压力差、吸收液流量、进气流量以及进气浓度等因素对脱硫效率的影响.结果表明,与清水及相同pH值的NaOH溶液相比,海水是一种对二氧化硫缓冲能力大,资源丰富,脱硫效率较高的吸收剂.在气液两相压力差保持在穿透压范围内时,以较低流量的海水吸收液处理较高流量的低浓度(SO2体积分数ψ为2 000×10-6以下)气体时,脱硫效率可达90%以上.因此膜吸收法海水脱硫技术在沿海地区具有广阔的应用前景.     

膜法海水吸收烟气中二氧化碳的试验研究

采用自制聚丙烯中空纤维膜接触器,以海水作为吸收剂,对模拟烟气中CO2进行吸收试验研究,主要考察烟气流量、CO2浓度、海水流量、海水pH值及膜填充率对CO2脱除率及膜接触器传质性能的影响.研究结果表明:(1)提高烟气流量或CO2浓度能提高膜接触器对CO2的处理量,导致脱碳率下降;(2)提高海水流量能明显提高脱碳率和传质速率;(3)提高海水pH可增大海水对CO2的吸收能力,直接决定了海水对CO2的吸收机制;(4)增大膜接触器填充率所对应的脱碳率并非最高,有效气液接触面积是影响脱碳率和过程传质的重要因素.     

气-液膜接触器法烟气脱硫脱硝的研究进展

气-液膜接触器以其比表面积大、体积小、模块化设计与安装和规模易于放大等优点,有望替代传统的湿法烟气脱硫脱硝装置.本文对气-液膜接触器法烟气脱硫脱硝的研究进行了综述,指出选择与开发高性能的吸收剂、构造合理的气-液膜接触器的结构、优化膜法烟气脱硫脱硝的操作工艺和烟气中同时脱硫脱硝等方面,是气-液膜接触器法烟气脱硫脱硝领域的主要研究方向.     

中空纤维膜接触器用于柠檬酸盐溶液吸收模拟烟气中SO2的研究

采用中空纤维膜接触器对柠檬酸盐溶液吸收模拟烟气中SO2的行为进行了研究.考察了柠檬酸盐溶液浓度、溶液pH值对膜吸收效果的影响,对比了不同中空纤维膜材料的吸收效果,考察了吸收液中硫酸根的生成情况.研究结果表明:增大柠檬酸盐浓度有利于提高SO2的吸收速率和容量;吸收液pH值越高,吸收效果越好;疏水性中空纤维膜吸收效果优于亲水性膜;吸收液中硫酸根离子浓度随时间基本呈线性增加,增加的速率约为0.192 g/(L.h).     

中空纤维膜接触器分离烟气中CO2试验研究

在中空纤维膜接触器分离CO2试验台上,对模拟烟气进行分离CO2试验,采用MEA、MDEA和氨基酸盐3种吸收液,考察了吸收液流速、浓度、温度以及气体流速和入口CO2浓度对CO2的脱除效率和系统阻力的影响。试验结果表明采用氨基酸盐吸收液,CO2的脱除效率可达90％以上,而气相阻力小于150Pa。因此该技术满足了锅炉烟气大、压力小的特点,非常适合于烟气中CO2的分离与回收,是一种很有前途的分离CO2的方法。     

PVDF膜接触器在电厂含氨废水处理中的应用研究

燃煤电厂含氨废水具有水量大、氨氮浓度高、水质波动大的特点,常规脱氨工艺处理困难.本文采用PVDF膜接触器处理燃煤电厂高浓含氨废水,考察了膜接触器类型、水侧流量、气侧真空度、气液接触面积、进水水质等因素对脱氮效率的影响.结果表明,基于PVDF膜接触器的气液分离工艺,能够将高浓含氨废水中的氨氮浓度由1 250 mg/L降至300 mg/L以下;外压式和内压式膜接触器都有理想的应用效果;提高膜接触器水侧流量、气侧真空度能够有效提高NH₃传质效率;增大传质膜面积能够显著提升循环液氨氮脱除率.提出了分离NH₃在燃煤电厂的多种资源化回用途径,为膜接触器的工程化应用提供参考.     

膜接触器分离混合气中二氧化碳

以N-甲基二乙醇胺（MDEA）水溶液为吸收剂,采用疏水性聚丙烯中空纤维膜组件（HFPPM）作为膜接触器,研究了膜接触器分离CO2/N2混合气传质性能,主要考察了吸收剂浓度,液速,吸收温度,原料气浓度和气速等因素对CO2吸收性能的影响,比较了同一膜组件不同流程和不同膜组件及膜形态对分离效果的影响,并对膜组件运行的稳定性进行了初步考察,实验结果表明,采用MDEA溶液和HFPPM膜接触器分离CO2/N2混合气具有较快的传质速率和较高的分离效率．     

燃煤烟气中Hg迁移转化特性研究

研究了300 MW煤粉锅炉系统选择性催化还原（selective catalytic reduction,SCR）、低低温电除尘器、海水脱硫、湿式电除尘器等超低排放设施在不同工况、不同煤种情况下的Hg迁移特性和脱除能力。结果表明：各工况下总汞排放浓度为1.16~2.90 μg/m³。最终排入大气中的汞主要以单质汞存在,还有少量氧化态汞,颗粒态汞被全部脱除;汞主要是在海水法烟气脱硫中被去除的,低低温电除尘器、海水脱硫、湿式电除尘器对总汞平均脱除率分别为25%、62%、37%;Hg²⁺占比是影响烟气中汞脱除效率的关键,气相中较高的Hg²⁺份额有利于在电除尘器和海水脱硫装置中获得较高的脱除效率;在该配备SCR脱硝、低低温电除尘器、海水脱硫、湿式电除尘器等超低排放设施的300 MW煤粉锅炉电厂中,总汞平均脱除率约为83%,能够实现较大程度的汞脱除。     

湿法烟气脱硫塔能效特性研究

针对湿法烟气脱硫能效规律欠缺问题,以150 MW超低排放机组湿法脱硫塔为研究对象,基于脱硫设备的主要能耗和脱硫效率构建了脱硫能效指标——脱硫能效值,并采用数值模拟和理论分析相结合的方法,探究了液气比、入口烟气量、烟气流速、入口SO₂质量浓度、烟气温度等参数以及不同喷淋层组合方式对脱硫能效特性的影响规律。结果表明：脱硫能效值为0.22~0.96 kg/（kW·h）,并随入口SO₂质量浓度增加呈正比例变化,随喷淋层组合数、液气比和入口烟气温度增加呈反比例变化,随入口烟气量和塔内烟气流速增加先上升后下降。研究结果可为脱硫技术评价和脱硫系统节能运行提供参考。     

Multi-pollutants simultaneous removal from flue gas

The multi-stage humidifier semi-dry flue gas cleaning technology, the CRS plasma flue gas cleaning technology and oxidative additive flue gas cleaning technology were investigated for multi-pollutants removal. The semi-dry flue gas cleaning technology using multistage humidifier and additive can improve oxidation and absorption, and it can achieve high multi-pollutants removal efficiency. The CRS discharge can produce many OH radicals that promote NO oxidation. Combining NaOH absorption can achieve high deSO2 and deNOx efficiencies. It is very fit of the reconstruction of primary wet flue gas desulfurization (WFGD). In addition, Using NaClO2 as additive in the absorbent of WFGD can obtain very high removal efficiency of SO2 and NOx.     

活性炭法脱硫脱硝的自动控制

烧结烟气活性炭法脱硫脱硝技术成功解决了烧结烟气量大、SO2浓度低、成份复杂等脱硫脱硝工艺技术的难题,在烧结脱硫脱硝领域取得了重大突破,其自动控制系统的成功开发与应用使工艺系统得以安全、高效、稳定运行.     

Simultaneous desulfurization and denitrification by microwave reactor with ammonium bicarbonate and zeolite

Microwave reactor with ammonium bicarbonate (NH(4)HCO(3)) and zeolite was set up to study the simultaneous removal of sulfur dioxide (SO(2)) and nitrogen oxides (NO(x)) from flue gas. The results showed that the microwave reactor filled with NH(4)HCO(3) and zeolite could reduce SO(2) to sulfur with the best desulfurization efficiency of 99.1% and reduce NO(x) to nitrogen with the best NO(x) purifying efficiency of 86.5%. Microwave desulfurization and denitrification effect of the experiment using ammonium bicarbonate and zeolite together is much higher than that using ammonium bicarbonate or zeolite only. NO(x) concentration has little effect on denitrification but has no influence on desulfurization, SO(2) concentration has no effect on denitrification. The optimal microwave power and empty bed residence time (EBRT) on simultaneous desulfurization and dentrification are 211-280 W and 0.315 s, respectively. The mechanism for microwave reduced desulfurization and denitrification can be described as the microwave-induced catalytic reduction reaction between SO(2), NO(x) and ammonium bicarbonate with zeolite being the catalyst and microwave absorbent.     

A modeling and experimental study of flue gas desulfurization in a dense phase tower

We used a dense phase tower as the reactor in a novel semi-dry flue gas desulfurization process to achieve a high desulfurization efficiency of over 95% when the Ca/S molar ratio reaches 1.3. Pilot-scale experiments were conducted for choosing the parameters of the full-scale reactor. Results show that with an increase in the flue gas flow rate the rate of the pressure drop in the dense phase tower also increases, however, the rate of the temperature drop decreases in the non-load hot gas. We chose a water flow rate of 0.6 kg/min to minimize the approach to adiabatic saturation temperature difference and maximize the desulfurization efficiency. To study the flue gas characteristics under different processing parameters, we simulated the desulfurization process in the reactor. The simulated data matched very well with the experimental data. We also found that with an increase in the Ca/S molar ratio, the differences between the simulation and experimental data tend to decrease; conversely, an increase in the flue gas flow rate increases the difference; this may be associated with the surface reactions caused by collision, coalescence and fragmentation between the dispersed phases.     

离子液体中阴阳离子的特性对其吸收二氧化硫的影响

SO_2是一种无色、有强烈刺激性气味的气体,弥散在空气中的SO_2对人体健康、生态环境有着严重的危害,是导致空气质量不断恶化的主要大气污染物之一。人为造成的SO_2污染物的主要来源有燃料燃烧、工业生产、交通运输等,其中燃料燃烧占70%。因此,削减和控制燃料燃烧所产生的SO_2的排放是我国能源利用和环保领域的重要研究方向,烟气脱硫是应对烟气中SO_2排放的有效途径。湿法烟气脱硫是目前应用最广泛的方法,占世界安装烟气脱硫机组总容量的85%,采用该方法处理的烟气占总处理量的80%。在湿法烟气脱硫技术中比较实用的主要包括钙法脱硫、有机胺脱硫、海水脱硫。其中,钙法脱硫的脱硫效率高,对煤种的适应性较强,但是脱硫会产生CaSO_4沉淀,降低经济效益;有机胺脱硫的系统腐蚀性小,副产品可生产硫酸,但是胺易挥发,造成吸收剂损失和环境污染;海水法脱硫的工艺简单、运行可靠,但其应用受到地域的影响,并且对环境也会产生一定的影响。离子液体是一种新兴的绿色介质,它具有环保、可再生、结构可调控的优点,为解决传统工艺中的污染问题提供了新方案。在离子液体吸收气体的过程中,吸收液不会因其挥发性而蒸发进入气相,并且可以在较低的温度下完成吸收解吸循环。离子液体的这些优良特性使其在SO_2吸收方面有着极广阔的应用前景。目前,研究者们已合成了一系列胍盐类、咪唑类、醇胺类、吡啶类等离子液体,探究其吸收SO_2的性能与机理,并根据其结构可设计的特点,在离子液体中的阴阳离子上引入各类官能团(如氰基、醚基、氨基、卤素),合成满足特定需求的离子液体,使其高效、可逆、低耗地吸收SO_2。本文总结了近年来各类离子液体吸收SO_2的性能和机理,为系统地认识离子液体在SO_2分离领域的应用提供了帮助;重点阐明了离子液体中阴阳离子的种类、官能化,尤其是酸碱性对其吸收SO_2的影响,这为调整离子液体酸碱性、合理设计离子液体的结构,探索离子液体吸收SO_2的机理,改善其对SO_2的吸收性能有着重要的价值。最后指出了目前研究中存在的问题并且对未来新型离子液体的合成进行了展望。     

Sulfation and attrition of calcium sorbent in a bubbling fluidized bed

A bubbling fluidized bed reactor was used as a desulfurization apparatus in this study. The height of the bed was 2.5 m, and the inner diameter was 9 cm. The bed materials were calcium sorbent and silica sand. The effects of the operating parameters of the flue gas desulfurization including relative humidity, temperature, superficial gas velocity, and the particle size of calcium sorbent on SO₂ removal efficiency and calcium sorbent conversion and attrition rate in the fluidized bed were investigated. It was found that the temperature effect in our system was negligible from 40 to 65°C. A higher relative humidity had a higher calcium conversion and a higher sulfur dioxide removal efficiency. Moreover, a smaller particle size of calcium sorbent had a lower calcium conversion in the cyclone but a higher sulfur dioxide removal efficiency. A lower superficial gas velocity resulted in a higher sulfur dioxide removal efficiency and a higher calcium conversion, thus, the total volume of the flue gas treated was maximum near the minimum fluidization velocity. Finally, an attrition rate model proposed in this study could predict the elutriation rate satisfactorily.