液相催化氧化法脱除烟气中SO2的研究

采用含Mn2 的吸收液催化氧化脱除烟气中SO2,研究了吸收液硫酸浓度、吸收液催化剂浓度、气体分布器和气体流量等控制条件对SO2的吸收率的影响。试验结果表明,采用w(MnSO4)为0.05%~1.00%的吸收液,其中的w(H2SO4)为2%~6%,选择理想的吸收设备,脱硫率可达98%以上。针对中小型燃煤锅炉中的废气和硫酸生产尾气,液相催化氧化法是一种很有前途的脱硫方法。     

Heterogeneity of V2O5 Supported Cylindrical Activated Coke Used for SO2 Removal from Flue Gas

V₂O₅ supported activated coke (V/AC) was shown to be a good catalyst for SO₂ removal from flue gas. In this work, the heterogeneities of cylindrical V/AC granules (Φ 8.5 · 12.6 mm) are investigated by peeling the granules layer by layer. The results show that the axial ends of the catalyst with a depth of ca. 2 mm contain more pores than other parts of the catalyst. This pore structure distribution results in a similar V₂O₅ distribution through impregnation and a similar S distribution after SO₂ removal. The results show that mass transfer is the main factor affecting SO₂ removal over large V/AC granules, and that SO₂ removal proceeds mainly along the axial direction of the granules. The granule should be made shorter in the axial direction and longer in the radial direction to improve utilization of V/AC.     

喷淋塔尾气脱氨实验研究

为了研究喷淋塔对硝酸磷肥尾气的脱氨特性,将空气和氨气按一定比例混合制成模拟尾气,用p H=1的稀硝酸溶液作为吸收剂,考察了空塔气速、喷淋密度、吸收液温度、混合气入口温度、入口氨浓度对脱氨体积传质系数KYa的影响。结果表明:KYa随着空塔气速的增加而显著增大;随着喷淋密度的增加,KYa先增大后趋缓;入口气相温度和氨浓度对KYa几乎无影响;随着吸收液温度的升高,KYa呈先增大后减小的趋势。     

催化法烟气同时脱硫脱氮技术研究进展

通过综述近年来研究较多的以催化法为基础的同时脱硫脱氮技术,包括基于SCR同时脱硫脱氮工艺和液相催化氧化技术,并介绍了各种工艺的特点,提出了催化法同时脱硫脱氮技术中存在的问题和今后的研究方向。     

Mercury Removal by Adsorption on Pectin Extracted from Sugar Beet Pulp: Optimization by Response Surface Methodology

Considering the rich sugar beet resource in Xinjiang, China, the possibilities for Hg(II) removal by pectin extracted from sugar beet pulp and optimization of the extraction process using response surface methodology (RSM) were studied. The experiments were proposed by Box‐Behnken design (BBD) and a second‐order regression model was developed for regression analysis and analysis of variance. Optimized conditions in terms of temperature, concentration, and solid‐liquid ratio were determined. The effects of different parameters like pH, time, temperature, and initial Hg(II) concentration on adsorption capacity were investigated. The isotherm adsorption experiments were fitted with the Langmuir model which indicated monolayer adsorption.     

酸性气体脱除单元副产二氧化碳中夹带甲醇的去除方案研究

酸性气体脱除单元副产的二氧化碳可作为粉煤气化装置载气循环利用,但其夹带微量甲醇,需经过处理才能达标排放。以某二氧化碳需求量为20000 m³/h的粉煤气化装置为例,分析对比了压缩机段间洗涤和压缩前洗涤两种水洗法脱除二氧化碳中微量甲醇的方案,结果发现水洗法脱除甲醇的方案可行,且压缩机段间洗涤方案较压缩前洗涤方案安全性更高,设备费用更低,能耗低15.5%,每小时可省操作费用105.1元。初步探讨了吸附法用于脱除二氧化碳中微量甲醇的可行性。     

活性炭纤维脱除有色冶炼烟气中SO_2的性能

有色金属冶炼烟气中SO2浓度高、气量波动大。目前还没有特别有效的处理技术脱除有色金属冶炼烟气中高浓度的SO2。本文采用粘胶基活性炭纤维(ACF)为脱硫剂,对脱除模拟有色冶炼烟气中SO2(0.3%-0.8%)的性能进行了研究,考察了水蒸气含量、床层温度、SO2浓度以及体积空速对ACF脱硫性能的影响。研究结果表明:随着水蒸气含量的增加,ACF脱硫效率逐渐提高,随着反应温度的增加,脱硫效率先增加后减小。当烟气中SO2浓度为0.8%时,在水蒸气含量为33.6%、反应温度为100℃及空速为500h-1时,脱硫效果最佳,平台阶段脱硫效率达41%。降低入口SO2浓度和体积空速可进一步提高ACF脱硫的穿透时间、穿透硫容和平台阶段脱硫效率。     

气-固-固流化床用于燃煤电厂尾气同时脱硫脱硝

采用新型干法气–固–固流化床反应器进行模拟燃煤电厂尾气的高效同时脱硫、脱硝. 在内径53 mm的流化床中,以砂粒作为固相介质、自制的K2CO3/Al2O3为吸附剂,考察了温度、吸附剂粒径、吸附剂活性组份(K)与气相中污染组份(SO2,NO)的摩尔比、模拟气中SO2/NO摩尔比等工艺条件对脱硫脱硝效率的影响. 在无氨条件下同时脱硫、脱硝的效率可分别达到100%和92%. 大量数据表明,尾气中的SO2对吸附剂表面NO的脱除反应有显著促进作用.     

Efficient Removal of Ammonia by Hierarchically Porous Carbons from a CO2 Capture Process

The amine-based post-combustion carbon capture process is one of the most efficient methods for treating large-scale CO₂, but it produces hazardous products due to chemical transition and degradation of the absorbents. In this study, carbon-based materials were used as adsorbents for the removal of NH₃, and their adsorption capacities, adsorption rates, and stabilities were examined by comparing commercial activated carbon (AC) with hierarchically porous carbon (HPC). HPC-Step4 possessed a higher number of total acid sites, resulting in higher NH₃ adsorption compared to AC. Despite the similar porosity, HPC-Step4 exhibited a higher adsorption rate constant and the improved kinetics was attributed to its increased portion of mesopores, enhancing the diffusion rate of the adsorbate. Furthermore, HPC-Step4 exhibited better reaction stability than AC.     

Mass Transfer and Liquid‐Film Formation in a Spray Tower for SO2 Removal in Sodium Hydroxide Solution

Spray towers allow for controlling air pollution in which a liquid is sprayed in small droplets to produce a large interfacial area for mass transfer between a gas and a liquid phase. An experimental study of a spray tower for removing SO₂ is described. The experiments were carried out under different operating conditions by varying the gas velocity, liquid flow rate, and SO₂ concentration. SO₂ removal efficiency, volumetric mass transfer coefficient, and liquid‐film formation as a result of the collision of droplets against the tower wall are investigated. Removal efficiency and volumetric mass transfer coefficient are analyzed as a function of gas velocity, liquid flow rate, and SO₂ concentration, while liquid‐film formation is evaluated as a function of tower height. The results indicate high removal efficiency. Correlations to predict the volumetric mass transfer coefficient are also proposed.     

Selective Removal of H2S from Gas Streams with High CO2 Concentration Using Hollow‐Fiber Membrane Contractors

Selective and simultaneous separation of H₂S and CO₂ from CH₄ was accomplished in a hollow‐fiber membrane contactor (HFMC). The absorption of both H₂S and CO₂ using an aqueous solution of methyldiethanolamine (MDEA) was almost complete and acid gases were totally removed. Despite the large difference between H₂S and CO₂ concentrations, the rate of H₂S absorption was not significantly influenced by CO₂ absorption. The independent effect and interactions of several process variables on the separation performance of H₂S and CO₂ were investigated. The results indicated that the membrane contactor could be a highly efficient choice for removal of almost all H₂S in the presence of a large CO₂ content even at high gas/liquid flow ratio. The selectivity of H₂S was about three times higher compared to the conventional absorption packed towers.     

填料塔中哌嗪二胺吸收低浓度SO_2的传质性能

为满足有机胺法脱硫设计开发的需要,采用动态吸收法测定了填料塔中哌嗪二胺(PA-A)水溶液吸收低浓度SO2的体积总传质系数KGa,考察了吸收工艺参数如吸收液中的PA-A浓度和初始pH值、液相流率、吸收温度、进气SO2浓度及流速等对KGa的影响。结果表明:KGa随着吸收液中的PA-A浓度和初始pH值、液相喷淋密度的增加而增大;随着吸收温度、气相流率及进气SO2浓度的增加而减小。通过实验结果分析得到体积总传质系数KGa与气液相流率比(qG/qL)之间符合指数关系式,该经验关系可用于工程设计计算。     

烟气脱硫脱硝一体化吸收/催化剂研究进展

由于对控制NOx排放的日益重视,具有同时脱硫脱硝功能的整体流程对于老厂改建和新厂建设有极大优势。详细介绍了采用金属氧化物在同一系统中实现烟气联合脱硫脱硝技术的研究现状、存在的问题及其发展前景。     

硫酸法生产钛白的废酸治理

介绍了硫酸法生产钛白粉过程中产生的废酸和酸性废水，采用浸没燃烧和真空浓缩将废酸浓缩；用升流式石灰石滤池中和处理废水。     

响应曲面法优化TiO_2/Cu复合粒子的制备工艺

以甲基橙的降解为研究目标,通过一阶响应曲面试验设计,研究主要因素对复合粒子的可见光活性影响规律,通过二阶模型建立了回归模型,获得了最优的实验条件是：SnC l4的量0.086 g;H2O的量6.72 mL;HCl的量0.007 mol;在最优条件下的可见光活性研究表明,复合粒子具有明显的可见光活性,能够有效降解甲基橙,降解率达到90%以上,且可以重复使用。     

焦炉煤气脱硫脱氰工艺的优化

通过对焦炉煤气脱硫系统中HCN分解装置的运行状况和存在的问题进行总结,找出了其堵塞原因,并在理论和实践分析的基础上对生产工艺进行改造、操作方法进行改进。经过改造后工艺实际生产效果明显改善,脱硫工序开工率、硫磺产量明显提高,取得了较好的经济效益和环境效益。     

响应面法优化管萼山豆根总生物碱提取工艺

采用微波控温辅助超声波的方法提取管萼山豆根茎中总生物碱,通过单因素法和响应面法优化了提取工艺,考察了管萼山豆根茎中总生物碱对1, 1-二苯基-2-三硝基苯肼自由基(DPPH·)、2, 2-联氮-二-3-乙基-苯并噻唑-6-磺酸自由基(ABTS·)和超氧阴离子自由基(O2?·)的清除作用。结果表明,模型优化并修正的最佳工艺条件为:提取时间37.8 min,微波加热温度64.5℃,超声功率575 W,乙醇体积分数95%,在该条件下总生物碱得率为0.5418%,高于不采用微波超声辅助的0.2436%、超声辅助的0.4538%、乙醇回流的0.3884%。管萼山豆根茎中总生物碱在DPPH·、ABTS·、邻苯三酚浓度分别为0.1、7.0、8.0 mmol/L条件下,其半数抑制质量浓度(IC50)分别为0.891、0.552和0.390 g/L。     

响应面法优化超临界CO2提取茶籽多糖的工艺研究

茶多糖具有多种重要的生物活性。本研究采用响应面法优化茶籽多糖的超临界CO2提取工艺,运用小星点设计考察萃取时间(30～150min)、压力(15～45MPa)、温度(40～80℃)及夹带剂乙醇浓度(50%～90%)四因素对茶籽多糖得率的影响。响应面分析表明,茶籽多糖得率与四因素关系符合二次模型。时间和夹带剂乙醇浓度的一次项和二次项、压力的二次项以及时间和压力的交互作用对茶籽多糖得率具有显著影响。该二次多项式模型用后退法进行逐步回归得到简化模型,依据简化后的模型在各因素设定范围内获得最佳提取工艺为:时间150min,压力45MPa,温度60℃,夹带剂乙醇浓度为65%。该条件下进行三次重复试验,茶籽多糖的实际平均得率为13.23%,与预测值13.96%无显著差异。