H202氧化——碱液吸收脱除NOx的工艺研究

针对制药行业NOx废气氧化度低、间歇排放的特点,提出了H2O2氧化--碱液吸收脱除NOx的方法.考察了H2O2质量分数、喷淋密度、氧化时间对NOx氧化度的影响以及氧化度、碱度对NOx吸收率的影响.结果表明,当温度为25℃、气体流量为8m3·h-1,NOx进口浓度为5000-6000mg·m-3,H2O2质量分数为2.5...     

NO2促进碱液吸收NO的作用机理

在鼓泡床反应器中实验研究了碱液吸收NOx过程中NO2对NO吸收的促进作用,考察了NaOH浓度、NOx体积分数、NO/NO2体积比及反应温度(283~358 K)对NOx吸收效率的影响. 结果表明,在NOx≥600′10-6(j), NO/NO2≤2(j)的条件下,NO2有效促进了碱液对NO的吸收,且吸收NO的效率高于NO2. 反应体系气相与液相产物分析表明,吸收过程产生的暂态中间活性组分存在类催化作用,其反应机理为NO2与气相中H2O反应生成HONO(+M),其部分在液膜分解生成NO(aq)和×OH,生成的NO(aq)进入液相,×OH与气相中的NO反应,促进了NO的吸收.     

H2O2氧化-碱液吸收脱除NOx的工艺研究

针对制药行业NOx废气氧化度低、间歇排放的特点,提出了H2O2氧化-碱液吸收脱除NOx的方法。考察了H2O2质量分数、喷淋密度、氧化时间对NOx氧化度的影响以及氧化度、碱度对NOx吸收率的影响。结果表明,当温度为25℃、气体流量为8m3.h-1、NOx进口浓度为5000～6000mg.m-3、H2O2质量分数为2.5%、氧化时间为13s、H2O2喷淋密度为15m3.m-2.h-1时,NOx氧化度最高,达到67.2%;当NOx氧化度为50%、碱度为30g.L-1时,NOx吸收率最高,达到96.1%。     

碱吸收法治理硝酸尾气

论述了碱吸收法治理硝酸尾气过程中,硝酸尾气酸雾、NOx浓度、碱液浓度对碱吸收的影响,并指出如何控制好吸收时间.     

NOx尾气治理的进展

叙述NOx治理方法和我国NOx治理现状,并结合工程实际,提出了经过改进后的酸吸和碱吸法。     

电晕-吸收法治理NOx废气技术

采用电晕结合现场化学吸收的方法对NO的去除效果进行了实验研究.电晕反应器为线筒式结构,作为吸收剂的Ca(OH)₂均匀地覆盖在筒壁的内表面.实验表明此法能有效地除去气流中的氮氧化物,NO的去除率大大高于反应器内没有固体吸收剂的情况,同时反应器出口NO₂的浓度小于12 mg•m^-3.可以认为反应器内的Ca(OH)₂吸收剂与NO的氧化产物NO₂或NO₃的吸收反应促进了NO的分解反应.研究还发现在气流中有氧气和水分存在时有利于NO的氧化反应和气固吸收反应,从而提高了NO的去除率.     

催化氧化-碱液吸收脱除硝酸工业NOx废气

碱液吸收脱除硝酸工业NOx废气中通常通过配气来提高脱除率,针对此方法导致的有效气损失及碱液消耗高的问题,提出了以改性活性炭(MAC)为催化荆的催化氧化-碱液吸收的处理工艺.探讨了相对湿度、氧化温度、氧化时间对NO催化氧化以及NOx氧化度对碱液吸收的影响.结果表明,相对湿度的增加强烈抑制了NO的转化;随着氧化温度从30℃升至90℃,干气条件下NO转化率由43%下降至19%,但湿气条件下NO氧化反应存在最佳反应温度为50～70℃.碱液吸收实验表明,氧化度为50%～60%时NOx脱除率最高,可达85%以上,催化氧化-碱液吸收的多级组合可实现硝酸工业废气中NOx的有效脱除.     

催化剂厂工艺尾气的回收治理

随着近些年来环保工作力度不断的加大,抚顺石化公司催化剂厂在生产过程中产生的含氨尾气和含酸尾气已经不能满足国家相关标准规范的要求,如果不及时对尾气进行回收处理,将会对企业的生产及未来发展造成很大的影响。介绍了某催化剂生产厂重整催化剂车间含酸尾气和加氢催化剂车间含氨尾气治理方案。     

碱液吸收法测定轻烃中CO_2

建立了轻烃中CO2测定的样品处理方法和两种滴定方法。样品经闪蒸器气化,然后用过量的NaOH溶液吸收CO2,生成Na2CO3,再用HCl标准溶液滴定。本方法6个样品的回收率为94.7%～97.4%。分析结果相对误差小于10%。满足了轻烃中CO2含量的检验要求。该方法适用于定量轻烃中CO2的分析。     

Removal of carbon dioxide from flue gases in packed column using ionic liquids

The study of CO₂ absorption in ionic liquids (ILs): [Emim] [Ac], [Bmim] [Ac] in a packed column is presented. The influence of mass transfer resistances, initial CO₂ concentration, absorption temperature and 2, 5, 10% wt. water addition on CO₂ removal efficiency was investigated. The resistance in series model and estimated values of enhancement factor were used to predict with good accuracy mass fluxes of absorbed carbon dioxide for both ILs. The CO₂ absorption efficiency in packed column depends on temperature and initial CO₂ concentration. The addition of small amounts of water to [Emim][Ac] is of minor effect on CO₂ absorption.     

Removal of carbon dioxide from flue gases with aqueous MEA solution containing ethanol

Adding ethanol to an aqueous amine solution offers several advantages for post-combustion CO₂ capture. The equilibrium isotherms at higher temperatures shift towards lower loadings, leading to an easier desorption. At constant temperature in the desorber bottom, the desorber pressure is increased, leading to energy savings in the CO₂ compression. Alternatively, at constant desorber pressure, the temperature in the desorber bottom is decreased, leading to a smaller efficiency drop of the power plant. Furthermore, the absorption rate of CO₂ is enhanced by adding ethanol. In the present work, the potential of using ethanol as a co-solvent for a 0.3 g/g aqueous monoethanolamine (MEA) solution is assessed based on simulations with an equilibrium stage model. A major drawback is the volatility of ethanol. The recovery of ethanol can be achieved using a water scrubber and subsequent stripping. The recovered ethanol vapor is sent directly to the desorber for heat integration. The process with ethanol recovery results in an increased complexity of the capture plant, difficulties in controlling the water balance and higher investment costs and offers, if any, only a moderate energetic advantage. The process concept could, however, be used for other co-solvents with similar properties as ethanol but lower vapor pressures.     

旋转填料床中硝酸吸收NO_x的实验研究(英文)

Absorption of NOx into nitric acid solutions was studied in the presence of ozone by using a rotating packed bed (RPB) contactor. The influences of operating parameters, such as high gravity number, amount of ozone, gas velocity, liquid spray density and inlet concentration of NOx, on the removal efficiency of NOx were investigated, among which the high gravity number and ozone amount are more important. Ozone was introduced to oxidize HNO2 to HNO3 to prevent the decomposition of HNO2 in the liquid phase. The high gravity number presents the effective external force for enhancing the mass transfer of ozone from gas phase to liquid phase. Under the experimental condition, the removal efficiency of NOx is higher than 90% and the concentration of nitric acid product exceeds 45%.     

Removal of nitric oxide and sulfur dioxide from flue gases using a FeII-ethylenediamineteraacetate solution

The combined absorption of NO and SO₂ into the Fe(II)-ethylenediamineteraacetate(EDTA) solution has been realized. Activated carbon is used to catalyze the reduction of Fe^III-EDTA to Fe^II-EDTA to maintain the ability to remove NO with the Fe-EDTA solution. The reductant is the sulfite/bisulfite ions produced by SO₂ dissolved into the aqueous solution. Experiments have been performed to determine the effects of activated carbon of coconut shell, pH value, temperature of absorption and regeneration, O₂ partial pressure, sulfite/bisulfite and chloride concentration on the combined elimination of NO and SO₂ with Fe^II-EDTA solution coupled with the Fe^II-EDTA regeneration catalyzed by activated carbon. The experimental results indicate that NO removal efficiency increases with activated carbon mass. There is an optimum pH of 7.5 for this process. The NO removal efficiency increases with the liquid flow rate but it is not necessary to increase the liquid flow rate beyond 25 ml min^?1. The NO removal efficiency decreases with the absorption temperature as the temperature is over 35 °C. The Fe²⁺ regeneration rate may be speeded up with temperature. The NO removal efficiency decreases with O₂ partial pressure in the gas streams. The NO removal efficiency is enhanced with the sulfite/bisulfite concentration. Chloride does not affect the NO removal. Ca(OH)₂ and MgO slurries have little influence on NO removal. High NO and SO₂ removal efficiencies can be maintained at a high level for a long period of time with this heterogeneous catalytic process.     

生物滴滤塔处理低浓度氮氧化物

采用活性炭填料挂膜的生物滴滤塔净化低浓度氮氧化物废气,研究结果表明,生物净化效率可达99%。适宜的喷淋量为3L/h,适宜的气体流量为0.4～0.5m3/h。当气体流量在0.56m3/h,入口气体氮氧化物浓度为480mg/m3,停留时间18.4s时,氮氧化物的净化效率可达到96.67%。净化氮氧化物的反硝化菌大部分为副球菌属(Paracoccus)中的细菌,也有小部分硫杆菌属(Thiobacillus)中的细菌。活性炭生物净化氮氧化物废气主要发生在活性炭外表面,而活性炭内表面发生的生化反应很少。     

烟气脱氮技术现状及展望

氮氧化物是大气主要污染物之一。近年来,烟气脱氮技术的研究一直是环保领域的新技术前沿研究热点之一。由燃煤而产生的大量低浓度NOx烟气是导致大气污染、酸雨和光化学烟雾危害严重的主要原因。研究烟气脱氮具有十分重要的意义。目前主要的烟气脱氮技术有选择性催化还原法、非催化选择性还原法、等离子体活化法、生物法以及微波法等。     

吸附法脱除烟气中NO_x研究

以秸秆作吸附剂进行固定床吸附实验。分别对1 mm～2 mm、3 mm～5 mm、7 mm～10 mm粒度的秸秆进行吸附实验。结果表明,1 mm～2 mm的秸秆颗粒吸附效果最好,吸附率可达到1 mg/g,是3 mm～5 mm秸秆吸附颗粒的二三倍;加料量越多,秸秆脱氮率越大;随着进口烟气流速的增大,秸秆对NOx的吸附率呈下降趋势,但在40 L/h～60 L/h时,脱氮率有一个稳定的范围。     

Absorption of NOx in packed column (II)

An absorption efficiency of packed column removing nitrogen oxides with water and NaOH solution under atmospheric pressure was studied. The efficiency and the acidity produced by absorption of NO, were measured in a packed column. The model developed that was based on the mass-transfer information for packed column and absorption mechanism accompanying the chemical reaction was compared with experimental results. Predictions using the model presented by the previous paper (part 1) was shown well to agree with from the experimental results (part II). The efficiency of NO_x, absorption is largely dependent on the height of packing material and the partial pressure of NO_x in the feed gas. The efficiency of NO_x absorption decreases with the increase of the acidity produced by recycling of water as a scrubber liquid. For the recycle mode with an aqueous NaOH solution as a scrubber liquid, NO_x absorption efficiency is shown to be constant until all of the C_OH- in the scrubber liquid are converted into C_H+.     

Main-chain photosensitive polyamic acids using alkaline aqueous solution as developer

In order to develop photosensitive polyimides (PSPIs) imaged in alkaline aqueous solution, a photosensitive diamine and relevant polymer containing conjugated double bonds in the main chain have been synthesized. The photosensitive characteristics and thermal stability of the polymers were investigated. These polymers possess good thermal stability and sensitivity to UV irradiation, and could be used to form a PSPI resist using alkaline aqueous solution as developer. © 1999 Society of Chemical Industry     

La-Mn-O钙钛矿催化剂成分对NOx和碳烟同时催化去除的影响

将La-Mn-O钙钛矿型催化剂与碳黑充分研磨后置于固定床连续流动反应体系中,利用程序升温反应(TPR)技术,对同时催化去除NOx和碳烟的反应进行了实验研究,考察了Ce、K及Cu的掺入对La-Mn-O钙钛矿型催化剂性能的影响.研究结果表明,用适量的Ce或K取代LaMnO3中的La,催化剂的性能可以得到改善,进一步用适量的Cu取代La0.8K0.2MnO3中的Mn,催化剂的性能也得到进一步的提高.用La0.8K0.2Cu0.05Mn0.95O3当作催化剂时,NO向N2的最大转化率达到66.0%,碳黑的起燃温度为290℃,结果表明该催化剂在同时去除NOx和碳烟方面具有较好的选择性和较高的活性.