液相高精度吸附脱除SO2新工艺在混合脱氢装置的工业应用

目的脱除作为混合脱氢装置原料的烷基化碳四(C₄)中的SO₂杂质,控制SO₂体积分数＜1×10-6。 方法采用液相高精度吸附脱硫工艺,通过吸附再生的方式实现其连续运行。当原料通过吸附脱除SO₂达到饱和后,流程上可通过氮气循环置换、升温汽提及空气再生的手段,重新恢复SO₂吸附剂的吸附能力,并再次投入生产使用,以确保装置的安全平稳长周期运行。 结果采用液相高精度吸附脱硫工艺可将烷基化C₄中SO₂体积分数从30×10-6~400×10-6脱除至1×10-6以下。 结论对吸附脱硫工艺的吸附剂、工艺流程进行优化调整,缩短了吸附剂的再生时间,保障了装置工业化连续运行。同时,液相高精度吸附脱硫工艺流程操作简便,能耗较低,安全风险较低。      

己内酰胺中挥发性碱杂质的控制

 针对己内酰胺成品中C₃~C₇直链酰胺、苯胺和己二酰亚胺等挥发性碱杂质含量偏高,影响产品质量的问题,研究了杂质控制方法。考察了真空蒸馏、树脂吸附、酸性/碱性水解等方法降低挥发性碱杂质含量的效果,并跟踪分析了工业装置中环己酮杂质对己内酰胺产品质量的影响。结果表明,真空蒸馏仅能脱除约20%正戊酰胺;Amberlyst强酸性树脂容易吸附脱除碱性较强的NH₃,而难以吸附脱除碱性弱的正戊酰胺、正己酰胺; NaOH质量分数由0增至500μg/g时,加速了挥发性碱杂质的水解速率,但也促进己内酰胺开环水解、低聚等副反应;H₂SO₄溶液中添加NaNO₂进行重氮化反应,明显加快了正戊酰胺、正己酰胺的水解速率,但大量己内酰胺同时存在时,H₂SO₄易与己内酰胺发生络合反应,导致杂质基本不进行水解反应。通过严格限制环己酮中己醛和2-庚酮杂质质量分数至20~30 μg/g,挥发性碱杂质含量明显下降,己内酰胺优级品率可达到100%。     

[C2OHMIM]+Cl－离子液体-水体系中纳米TiO2的合成及光催化性能

 采用[C₂OHMIM]⁺Cl^-离子液体 水体系混合加热法制备了纳米 TiO₂光催化剂,应用 XRD、SEM 和 UV-Vis 手段对其进行了表征,考察了体系中[C₂OHMIM]⁺Cl^-质量分数、反应时间和反应温度对所制备的纳米 TiO2的颗粒结构、形貌及光催化活性的影响。结果表明,由此法得到的 TiO₂均为金红石相,由纳米晶小颗粒堆积起来的球形颗粒组成。当[C₂OHMIM]⁺Cl^-质量分数为66.6%、反应温度150℃、反应时间24 h 时,制备所得 TiO₂的光催化活性好,对罗丹明B的降解率高达96%。     

Fe 3+x-TiO2/Shell光催化剂的制备及其对石油的光催化降解

 以自制的贝壳基规整吸附体为载体,采用浸渍煅烧法制备了Fe ³⁺_x-TiO₂/Shell光催化剂。采用XRD、SEM-EDS和UV-Vis等技术对制备的Fe ³⁺_x-TiO₂/Shell光催化剂进行表征。以石油为降解对象,考察了Fe³⁺掺杂量、Fe ³⁺_x-TiO₂/Shell的负载次数及光照时间对Fe ³⁺_x-TiO₂/Shell光催化活性的影响。结果表明,Fe³⁺掺杂量为0.7%(m(Fe³⁺ )/m(TiO₂)×100%)、Fe ³⁺_0.7-TiO₂负载次数为4次时,制备的Fe ³⁺_0.7-TiO₂/Shell光催化剂的光催化活性最高,300 W碘钨灯照射16 h,石油的光催化降解率达76%。     

海水中瓜尔胶溶胀性能研究

针对海上连续混配海水基压裂液过程中稠化剂溶胀问题,开展了瓜尔胶溶胀性能的研究。考察了瓜尔胶取代基类型、取代度、搅拌速度、瓜尔胶加量、pH值和温度对瓜尔胶溶胀性能的影响。结果表明,我国某海域海水水样矿化度为34440 mg/L,富含Na⁺、Mg²⁺、Ca²⁺和Cl^-、SO₄^2-。在常规条件下（20℃、300 r/min、pH=7.5）,羧甲基瓜尔胶、羟丙基瓜尔胶（取代度0.30）、羟丙基瓜尔胶（取代度0.15）、未改性瓜尔胶在海水中的溶胀时间分别为25、50、55、60 min,对应的表观黏度分别为63、59、45、23 mPa·s。以羧甲基瓜尔胶为研究对象,考察其他因素对溶胀性能的影响。优选的配制方案为：搅拌速度400~500 r/min、温度30~40℃、pH值6~7,瓜尔胶加量0.5%以内。溶胀时间能控制在10 min以内,满足连续混配海水基压裂液施工要求。     

MoP/SiO2-TiO2-ZrO2催化喹啉加氢脱氮的反应动力学

 采用共沉淀法和共浸渍法制备了MoP/SiO₂-TiO₂-ZrO₂催化剂。以喹啉为模型化合物,在固定床微反应器中考察了MoP/SiO₂-TiO₂-ZrO₂催化剂的加氢脱氮（HDN）活性;在氢分压2~5 MPa、反应温度300~400℃、氢/油体积比200~800和体积空速2~8 h^-1条件下,建立了其HDN的反应动力学模型。结果表明,MoP/SiO₂-TiO₂-ZrO₂催化喹啉HDN反应中,脱氮率随着反应温度升高先增加后趋于平缓,喹啉转化率则随着反应温度升高略有降低;脱氮率及转化率均随着氢分压增加而增加,随着体积空速增加而降低,而随着氢/油体积比增加变化不大。喹啉HDN的反应动力学模型为带有氮化物吸附的拟一级反应动力学模型,并结合Levenberg-Marquardt(L-M)算法对模型参数进行优化求解。将喹啉HDN反应的脱氮率实验值与模型计算值进行了比较,两者吻合较好,平均相对误差为6.87%。     

HCHO-H2SO4缩合-萃取脱除汽油中噻吩硫化物

 缩合-萃取脱硫是利用 FCC 汽油中的噻吩类硫化物与 HCHO 在 H₂SO₄存在下发生缩合反应,生成的噻吩缩合物被抽提至水相,从而达到脱硫的目的。考察了 HCHO-H₂SO₄体系对 FCC 汽油缩合 萃取脱硫的效果。当 HCHO-H₂SO₄体系中 HCHO 占模拟汽油的体积分数为1.5%、H₂SO₄ (质量分数55%)占模拟汽油的体积分数为10%、反应温度70℃、反应时间60 min 时,缩合 萃取脱硫后模拟汽油的硫质量分数由1163 μg/g 降至139 μg/g,脱硫率为87.96%;但是对硫质量分数为652 μg/g 的 FCC 汽油的脱硫率仅为10.74%;固定 HCHO 与 H₂SO₄的体积比,增加二者的用量有助于提高 FCC 汽油的脱硫率。该体系对硫含量低的 FCC 汽油以及 FCC 重汽油脱硫效果较好,当 HCHO-H₂SO₄占 FCC 汽油的体积分数为40%时,FCC 中汽油硫质量分数由164 μg/g 降至65 μg/g,脱硫率达到60.37%。     

NH4Ca(NO3)3内相油基钻井液性能探讨

分别以CaCl₂、HCOOK、HCOONa和NH₄Ca(NO₃)₃为内相,配制具有相同活度（0.9）、相同密度（1.8 g/cm³）的油基钻井液体系,油水体积比为80∶20。比较了4 种钻井液的流变性、动态/静态沉降性能、黏弹性、触变性,考察了NH₄Ca(NO₃)₃钻井液的抗污染能力。结果表明,150℃滚动老化16 h 后,相同剪切速率下,NH₄Ca(NO₃)₃内相油基钻井液体系剪切应力最小,黏度最低。在50℃、170.3 s^-1下,该体系密度降低了0.255 g/cm3,其他3 种钻井液的密度降低值⊿ρ为0.513～0.545 g/cm³;相同剪切应力下,NH₄Ca(NO₃)₃钻井液弹性模量和黏性模量的比值（G'/G'）最大,体系动态沉降稳定性能最好。在10000 r/min 下搅拌30 min 后在50℃静置16 h,NH4Ca(NO3)3钻井液体系的表面张力为27.744 mN/m²,上层分离油体积为1.37 mL,剩余溶液的上下层密度差为0.038 g/cm³;该体系的凝胶尖峰为3.47 Pa,静态沉降稳定性和触变性最好。NH4Ca(NO3)3钻井液体系抗污染能力较强,可以抗10%劣土污染和15%盐水侵入污染     

氟硅酸铵同晶置换改性 ZSM-22分子筛的催化性能

 分别采用不同浓度的(NH₄)₂SiF₆水溶液对 ZSM-22分子筛进行同晶置换改性,并采用 XRD、N₂吸附-脱附、NH₃-TPD、Py IR、²⁹Si MAS NMR 对同晶置换改性前后的分子筛进行了表征,考察(NH₄)₂SiF₆改性对分子筛孔道结构及酸性的影响。将改性前后的分子筛用浸渍法制备了0.5%Pd/ZSM-22双功能催化剂,并在连续微型固定床反应装置上考察了其对正癸烷（n-C₁₀）加氢异构化反应的催化性能。结果表明, (NH₄)₂SiF₆改性选择性地脱除了分子筛的部分强酸中心,有效地抑制了正癸烷的裂化反应。用0.3 mol/L(NH₄)₂SiF₆溶液改性后的分子筛制备的Pd/ZSM-22催化剂的加氢异构化反应活性和异构化选择性均得到提高。     

介孔CuO/SiO2用于汽油氧化-吸附脱硫

 利用[(C₁₆H₃₃) N(CH₃)₃]₃-[PW₁₂O₄₀]双亲催化剂与H₂O₂组成的催化氧化体系对汽油进行氧化后,以介孔SiO₂为载体等体积浸渍法制备的介孔CuO/SiO₂为吸附剂,采用固定床连续流动式吸附脱硫评价装置,考察了CuO/SiO₂的CuO负载量、焙烧温度、焙烧时间和吸附温度对汽油脱硫率的影响,并对介孔CuO/ SiO₂吸附剂性质进行了XRD表征。结果表明,采用在焙烧温度为400℃、焙烧时间为2.0 h、CuO负载量为2%制备的CuO/SiO₂, 在吸附温度为120℃时,汽油氧化-脱硫的脱硫效果较好,汽油脱硫率可达56.82%。     

Industrial use of vessels with a three-phase fluidized bed

Results are cited for industrial tests on vessels subjected to the following processes: absorption of NO_x (by) nitric acid, and SO₃ by sulfuric acid; desulfurization of flue gases by a calcareous solution during both low and high gas-flow rates; cleaning gases of harmful components (SO₂, NO_x, H₂S, HF); and dust collection.     

Industrial use of vessels with a three-phase fluidized bed

Results are cited for industrial tests on vessels subjected to the following processes: absorption of NO_x (by) nitric acid, and SO₃ by sulfuric acid; desulfurization of flue gases by a calcareous solution during both low and high gas-flow rates; cleaning gases of harmful components (SO₂, NO_x, H₂S, HF); and dust collection.     

PRECIPITATION OF IRON,SODIUM, AND POTASSIUM IMPURITIES FROM SYNTHETIC SOLUTIONS MODELING SPENT ACID STREAMS FROM A CHEMICAL COAL CLEANING PROCESS

ABSTRACT

Experiments on treating model spent acid streams from a chemical coal cleaning process by double salt precipitation indicated that simple heating of solutions containing Fe₂(SO₄)3, Na₂SO₄, and K₂SO₄ caused jarosite (KFe₃(SO₄7)₂(OH)₆) to form preferentially to natrojarosite (NaFe₃(SO₄)₂(OH)₆), and precipitate yields were higher than when Na₂SO₄ was the only alkali sulfate present. Virtually all of the K, about 90% of the Fe, and about 30% of the SO₄ ^2? could be precipitated at 95°C, while little or no Na was removed. However, simply heating Fe₂(SO₄)₃/Na₂SO₄ solutions up to 95°C for <12 hours did not produce adequate precipitate yield's. When Na was the only alkali metal present, the Fe concentration in the solution had to be increased to avoid formation of undesirable iron compounds. Increasing the Fe concentration to about 6 g/L by adding excess Fe₂(SO₄)₃ suppressed the formation of undesirable iron salts and increased natrojarosite yields significantly, but the amount of precipitate obtained was less than half of the theoretical yield based on concentrations of the ions in solution. When either CaCO₃, Ca(OH)₂ or ZnO was used to maintain a pH value of 1.5 in solutions of Na₂SO₄/Fe₂(SO₄)₃ containing excess Fe, precipitate yields increased dramatically at 80 and 95°C. When CaCO₃ was used, the precipitate consisted of natrojarosite and gypsum (CaSO₄·2H₂O). In one of the tests, at least 99% of the Fe and 50-75% of the Na was removed. Complete removal of Na in those tests was probably precluded by hydronium ion substitution for the Na     

Relative rates of CH3NO2, CH3ONO,and CH3ONO2 formation in the thermal reaction of NO2 with acetaldehyde and DI-T-butyl peroxide at low temperatures

Abstract

The relative yields of CH₃NO₂, CH₃ONO, and CH₃ONO₂ have been measured at five temperatures between 323 and 455 K above 300 torr of pressure. Kinetic modelling of the observed CH₃NO₂/(CH₃ONO + CH₃ONO₂) and CH₃ONO/CH₃ONO₂ ratios from this study and that of Phillips and Shaw (Ref. 5), with and without added NO, led to the rate constant for CH₃ + NO₂ → CH₃NO₂ (1), k₁ = 6.0x10¹² cc/mol-sec, and for CH₃O + NO₂ → CH₃ONO₂ (4), k₄ = 7.5x10¹² cc/mol-sec. The results of the modelling also indicate that the oxidation of CH₃NO by NO₂ accounts for a large fraction of CH₃NO₂ formed in the NO-added mixtures. The rate constant for this reaction is estimated to be k₂₅ ? 1.3×10⁹e^(-10,000/RT) cc/mol-sec. Combination of k₁ with the equilibrium constant for reaction (1) gives rise to the rate constant for the decomposition of CH₃NO₂, k_?1 = 1.3x10¹⁶e^(-60,050/RT) sec^?1.     

Ni-Zn复合氧化物用于反应吸附脱除噻吩

采用均匀共沉淀法制备了Ni-Zn复合氧化物吸附剂,并在固定床上考察了预还原、吸附条件、模拟油的不同组分对其吸附脱硫性能的影响。结果表明,还原态的Ni是吸附剂的主要活性成分,吸附反应最适宜的温度和压力分别为673 K、1.0 MPa,模拟油中的烯烃组分对吸附剂脱硫性能的影响比芳烃的影响大。吸附剂在温度673 K、压力1.0 MPa、液时空速60 h^-1、氢气与模拟油的体积比为200（氢气体积为标准状态下的体积）时对含硫质量浓度100 mg/L的模拟油A的硫容为360 mg/g。噻吩首先在Ni原子上进行氢解生成H₂S,然后H₂S快速与ZnO结合生成ZnS。此外该吸附剂对原料有很好的适应性,并具有很好的再生性能。     

Effects of hydrogen enrichment on diesel engine fueled with Afzelia Africana biodiesel – TiO2 blends

Owing to strict emission-policies, vehicle manufacturers are mandated to control hazardous emissions from diesel engines. One novel step adopted in this work, is the use of hydrogen enrichment with nanofuel, where TiO₂ nanoparticles- Afzelia Africana biodiesel-mix was blended with hydrogen for use in a diesel engine. 25 ppm TiO₂ nanoparticles were admixed with biodiesel and ultrasonicated. Thereafter, H₂ was introduced through the air inlet at the lowest possible flow rate (3–4 LPM) to avoid reaching H₂/air explosion limit. The ratio of H₂ to the blended fuels (BNH) is (15: 85 vol/vol %). The effects of the nanofuels blended with pure H₂ were investigated by evaluating the brake thermal efficiency (BTE), wall temperature of the combustion chamber, NO_x, CO, and HC emissions. Via a simplified model, the associated uncertainties in the parametric variations were determined while a Supervisory Computer Aided Data Acquisition (SCADA) system with an in-built program, was configured in the engine set-up for data generation. The results showed that higher BTE of the blends + 25 ppm TiO₂ alongside hydrogen flowrates of 3 LPM and 4 LPM helped to improve the engine performance with lesser emissions of CO, NO_x and HC respectively. Sample BNH@-3-LPM gave the best performance/BTE of 39.5 % compared to BNH@-4-LPM (32.4 %), BN (29 %) and diesel (29.4 %), whereas, BNH@-3-LPM gave the lowest emissions of 0.4, 5 and 81 g/kwh for CO, HC and NO_x respectively compared with diesel which gave corresponding emissions of 0.8, 35 and 200 g/kwh for CO, HC and NO_x respectively.     

双核磺化酞菁钴与硫化钠反应的伏安法研究

PDS脱硫法有效解决了氰化氢中毒问题,得到许多企业的青睐,但副盐问题仍然是目前整个脱硫行业十分关注的话题。采用循环伏安法对PDS脱硫体系中双核磺化酞菁钴(bi-CoPc)与硫化钠的反应过程进行了研究。结果表明:Na_2S和Na_2S_x在玻碳电极上的氧化反应是受浓度扩散控制的不可逆反应,且S~(2-)向S_8的转化并不是一步完成,而是先转化成S_x~(2-),进而再生成S_8。此外,参与反应的S~(2-)仅有20%转化为S_8。S_x~(2-)以S_2~(2-)～S_9~(2-)中的某两种形式为主要存在形式,且S_x~(2-)的存在形式可能对于S_8的生成速率和生成量有一定影响。bi-CoPc在水溶液中易与OH~-形成配合物,加入碳酸盐缓冲溶液,可降低配合物的形成能力,同时,Co~+/Co~(2+)的氧化还原反应更易发生。bi-CoPc与Na_2S反应先生成S_2~(2-),然后S_2~(2-)可转化为更长链的S_x~(2-),最终形成S_8。该研究结果有助于加深对脱硫机理的了解,同时,对降低副产物生成有一定的指导意义。     

Kinetics and mechanism of the thermal decomposition of dimethylnitramine at low temperatures

Abstract

Dimethylnitramine (DMNA) was pyrolyzed between 466 and 524 K at about 475 Torr pure DMNA pressure in static cells. A radical mechanism was proposed and computer-modeled to account for the disappearance of DMNA and the production of (CH₃)₂NNO and CH₃NO₂. The rate constant for DMNA decomposition into (CH₃)₂N and NO₂, based on these low-temperature results and other high-temperature shock tube data, covering 460–960 K, can be given by k₁ = 10^15.9±0.2 exp(?22,000±200/T) sec^?1. This result leads to values for the N-N bond energy of 43.3±0.5 kcal/mole and the heat of formation of the (CH₃)₂N radical, 35±2 kcal/mole at 298 K. Kinetic modeling of the CH₃NO₂ and (CH₃)₂NNO production profiles has been carried out.     

Combustion of petroleum residue in a batch type fixed bed reactor

Combustion is a highly efficient technology for energy conversion of biomass materials, municipal wastes, and fossil fuels. In this study, combustion tests of two petroleum residues (P1, P2) in a batch type fixed-bed reactor were presented for different operating conditions. The effects of air flow rate (50–70 L/min) on the combustion parameters (gas temperature and carbon conversion) were performed. Additionally, the influence of fuel flow rate on the environmental characteristics (NO_x emissions) was evaluated. The experimental results demonstrated that air flow rate is the most important factor in the process; a higher air fuel rate contributed to higher NO_x emissions and gas temperature. It also was found that the NO_x emissions increase dramatically when the air flow rate increases.     

O/W微乳体系制备固体超强酸SO42-/SnO2-Ta2O5及其表征

采用十二烷基苯磺酸钠（SDBS）-乙醇-环己烷O/W微乳体系制备了固体超强酸SO42-/SnO2-Ta2O5,对催化剂进行了傅里叶变换红外光谱、热重、X射线衍射表征,对催化剂的制备条件进行正交实验优化,并进行了稳定性考察。结果表明,催化剂的最佳制备条件为：SnCl4浓度0.1 mol/L、SnCl4溶液/SDBS/乙醇/环己烷质量比500﹕1﹕0.5﹕15、Ta2O5/SnO2质量比6%、陈化时间24 h、浸渍液硫酸浓度3.0 mol/L、焙烧温度550 ℃、焙烧时间3 h。将此条件下制备的SO42-/SnO2-Ta2O5用于催化乙酸与正丁醇的酯化探针反应,酯化率为99.3%。与常规水体系制备的催化剂相比,SDBS的O/W微乳体系有利于催化剂活性、稳定性的提高。