CORRELATION FOR ESTIMATING SOLUBILITY OF OXIDIZED COAL IN ETHANOLAMINE

The effect of reaction time in aerial oxidation of Assam coal on variation in moisture with wt% solubility in ethanolamine is presented. The effects of variation in helium density, specific energy, carboxyl acidity, and acid equivalent values on wt% solubilities of oxidized coal in ethanolamine are also highlighted. It is observed that progressive increase of oxidation time caused an increase in the moisture content and wt% solubility of oxidized coal in ethanolamine. The solubility of oxidized coal is found to correlate linearly with helium density, specific energy, acid equivalents, and carboxyl acidity on univariate basis with correlation coefficients of 0.88, 0.996, 0.992, and 0.995, respectively.     

Correlation for estimating solubility of oxidized coal in ethanolamine

The effect of reaction time in aerial oxidation of Assam coal on variation in moisture with wt% solubility in ethanolamine is presented. The effects of variation in helium density, specific energy, carboxyl acidity, and acid equivalent values on wt% solubilities of oxidized coal in ethanolamine are also highlighted. It is observed that progressive increase of oxidation time caused an increase in the moisture content and wt% solubility of oxidized coal in ethanolamine. The solubility of oxidized coal is found to correlate linearly with helium density, specific energy, acid equivalents, and carboxyl acidity on univariate basis with correlation coefficients of 0.88, 0.996, 0.992, and 0.995, respectively.     

老龄垃圾渗滤液高氨氮的电化学氧化及其能耗分析

针对垃圾渗滤液高氨氮、难生物降解的特点,采用电化学氧化法对含高浓度氨氮的垃圾渗滤液进行预处理,考察了不同电极材料、电流密度、Cl-质量浓度、pH、极水比等因素对渗滤液中高NH3-N去除的影响,分析了电化学氧化法处理垃圾渗滤液的能耗和电流效率。结果表明,在电流密度30 mA.cm-2、Cl-质量浓度5 000 mg.L-1、pH为8、极水比17.8 m2.m-3的条件下,以Ti/RuO2-IrO2-TiO2电极为阳极电解6 h后,NH3-N的去除率、电流效率和比能耗分别为99.9%、35%和91.9 kWh.kg-1。     

Characterisation of the surface of oxidised carbon adsorbents

The surface reactivity and functional group content of a series of oxidised active carbons has been assessed by elemental analysis, electrophoretic mobility measurements and potentiometric titrations. Oxidation of carbons with hot air resulted in a greater proportion of relatively weak acidic surface functional groups (i.e., phenolic), whereas nitric acid modification produced a greater amount of carboxylic groups. Electrophoretic mobility measurements suggest that the carbon surface is negatively charged within the range of the pH values studied. pH titration results indicate that the surface acidity of active carbons is stronger than that of a commercial polymeric carboxylic acid ion exchange resin. Possible mechanisms of carbon surface oxidation are discussed.     

Preparation of active carbons from coal Part I. Oxidation of coal

The oxidation of coals of different rank, origin and particle size has been studied at temperatures between 423 and 543 K and for time intervals between 6 h and 42 days. The chemical composition of the oxidised coal depends upon the coal rank, its particle size and the degree of oxidation as determined by the temperature and the time of oxidation. At higher degrees of oxidation, whether at higher temperatures for shorter time intervals or at lower temperatures for longer time intervals, the oxidised coal tends to approach similar chemical compositions. The weight of coal also changes on oxidation, the increase or decrease in weight depending upon the rank and the oxidation conditions. The rate and extent of oxidation decrease with increase in particle size because the larger particles slow down the diffusion of oxygen into the coal particles. The oxidation can eliminate completely the plastic properties of bituminous coal which inhibit the formation of anisotropic structures and enhance the development of a primary pore structure. The helium density increases with the degree of oxidation but the mercury density initially increases and then decreases. A minimum in the mercury density is obtained when the carbon content of the oxidised coal is around 85–90%. The oxidation significantly enhances the porosity and the surface area, the extent of increase depending upon the nature of the coal and the degree of oxidation. The changes in chemical composition, porosity and surface area with the degree of oxidation indicate that the oxidation of coal involves two different mechanisms, one operating at lower temperatures and the other at higher temperatures.     

OXIDATION OF METHACROLEIN AND ISOMERIZATION OF n-BUTENE OVER HETEROPOLY COMPOUNDS

The various salts of 12-molybdophosphoric acid were used for the oxidation of methacrolein and the isomerization of n-butene. The structure of the heteropoly compounds was identified with the aid of infrared spectroscopy, x-ray diffraction, and thermal analysis. The catalytic activity, acidity, and the reaction rate for oxidation of methacrolein were determined by micro-reactor with gas chromatography. The oxidation rate was proportional to the partial pressure of methacrolein and independent of those of oxygen and steam. The catalytic activity of alkali and alkaline earth metal salts was inversely proportional to the electro-negativity of metal elements. It was also revealed that the acidity of catalysts was strongly correlated with the catalytic activities for the oxidation of methacrolein and the isomerization of n-butene.     

OXIDATION OF METHACROLEIN AND ISOMERIZATION OF n-BUTENE OVER HETEROPOLY COMPOUNDS

The various salts of 12-molybdophosphoric acid were used for the oxidation of methacrolein and the isomerization of n-butene. The structure of the heteropoly compounds was identified with the aid of infrared spectroscopy, x-ray diffraction, and thermal analysis. The catalytic activity, acidity, and the reaction rate for oxidation of methacrolein were determined by micro-reactor with gas chromatography. The oxidation rate was proportional to the partial pressure of methacrolein and independent of those of oxygen and steam. The catalytic activity of alkali and alkaline earth metal salts was inversely proportional to the electro-negativity of metal elements. It was also revealed that the acidity of catalysts was strongly correlated with the catalytic activities for the oxidation of methacrolein and the isomerization of n-butene.     

乙烯装置综合能耗的计算

目前石油化工企业综合能耗计算标准不同,对于这种情况,作者以有效能为计算基础,并以乙烯装置为例,提出了作为主要能源的各种等级蒸汽和电力的当量燃料热值的计算和确定的方法。     

Protective effect of olive oil and its phenolic compounds against low density lipoprotein oxidation

The protective effect of phenolic compounds from an olive oil extract, and of olive oils with (extra-virgin) and without (refined) phenolic components, on low density lipoprotein (LDL) oxidation was investigated. When added to isolated LDL, phenolics [0.025–0.3 mg/L caffeic acid equivalents (CAE)] increased the lag time of conjugated diene formation after copper-mediated LDL oxidation in a concentration-dependent manner. Concentrations of phenolics greater than 20 mg/L inhibited formation of thiobarbituric-acid reactive substances after AAPH-initiated LDL oxidation. LDL isolated from plasma after preincubation with phenolics (25–160 mg/L CAE) showed a concentration-dependent increase in the lag time of conjugated diene formation after copper-mediated LDL oxidation. Refined olive oil (0 mg/L CAE) and extra-virgin olive oil (0.1 and 0.3 mg/L CAE) added to isolated LDL caused an increase in the lag time of conjugated diene formation after copper-mediated LDL oxidation that was related to olive oil phenolic content. Multiple regression analysis showed that phenolics were significantly associated with the increase in lag time after adjustment for effects of other antioxidants; α-tocopherol also achieved a statistically significant effect. These results indicate that olive oil phenolic compounds protect LDL against peroxyl radical-dependent and metal-induced oxidation in vitro and could associate with LDL after their incubation with plasma. Both types of olive oil protect LDL from oxidation. Olive oil containing phenolics, however, shows more antioxidant effect on LDL oxidation than refined olive oil.     

INFLUENCE OF ACTIVATED CARBON OXIDATION TREATMENTS ON THE SELECTIVE REMOVALOF COPPER AND LEAD

Air, acid, and electrochemical oxidation treatments have been employed to carefully control the amount and distribution of acidic surface groups in a series of activated carbons prepared from apricot stones. The surface reactivity and functional group distribution of oxidized active carbons have been assessed using numerous analytical and surface measurement techniques including nitrogen sorption, elemental analysis, potentiometric titrations, zeta potential measurements, and Boehm's titrations. Preliminary electrochemical oxidation results suggest that this treatment provides better control of the resultant surface acidity of the prepared carbons. Lead and copper sorption studies indicate that it is possible to alter the selectivity of the oxidized active carbons towards heavy metals by changing the quantity and/or relative proportion of the individual oxygenated surface functional groups.     

加压流化床中褐煤空气氧化制取腐殖酸的研究

为了加速空气氧化生成腐殖酸的反应速度,以及为采用连续过程的可能性提供科学和工艺的依据,在加压流化床中进行了札賚诺尔褐煤空气氧化制取腐殖酸的研究。在本试验装置中考察了压力（0～20大气压）、温度（150～190℃）等条件对腐殖酸生成速度的影响。试验结果指出:压力对于腐殖酸的生成速度有显著影响,达到腐殖酸含量为80％左右所需要的时间与压力成反比关系;温度也是影响腐殖酸生成速度的重要因素,但在该种反应器中,由于结构的限制,散出在氧化早期所产生的大量反应热是很困难的,因此反应温度难以进一步提高,而存在一个“高限温度”。 在本文试验条件下最佳的工艺条件为:20大气压,170℃,反应1.5小时;或为5大气压,190℃,反应2.5～3小时。在这两种情况下,氧化煤中腐殖酸含量为85～87％左右,羧基含量为2.1～2.4毫克当量数/克无灰无水氧化煤左右。     

Acidity of oryzanol and its contribution to free fatty acids value in vegetable oils

Model oil systems containing physically refined rice bran oil to which oryzanol was added were examined to determine the effects of oryzanol concentration on FFA values. When oryzanol was added to the model oils at a 0.5% level and FFA was determined, increases in FFA value were 0.28% as determined with phenolphthalein, 0.58% with thymolphthalein, and 0.07% with alkali blue 6B. Oils containing added oryzanol at 0.5–1.5% showed a proportionate increase in FFA values with an average increase of 0.413% per gram of oryzanol. A direct titration of purified oryzanol showed an acidity of 42.5% expressed as FFA. In spectroscopic studies, the phenolic group in the ferulic acid moiety of oryzanol was titrated by sodium hydroxide. Based on these data, indicator correction factors for oryzanol's acidity and a formula for calculating real FFA content of vegetable oils containing oryzanol were developed.     

反应条件对石蜡深度氧化制取二元酸的影响

研究了石蜡液相深度氧化过程中氧吸收量与氧化蜡组成变化的关系。结果说明,深度氧化蜡绝大部分是由多官能团酸组成,其官能团除羧基为主外,次为酯基,其量为羧基的一半,羰基较少,而羟基几无。C_4～C_（10）二元酸在氧化醋酸价为250毫克KOH/克左右时开始有明显的含量,并且随着氧化深度的增加而含量迅速增加。在适宜的催化剂和较好的气液接触情况下,石蜡能否快速定向深度氧化的关键在于恰当的选择温度和氧分压;使整个反应过程中氧化尽可能在化学动力学控制范围内进行,减少扩散因素的影响。试验结果表明,氧化蜡的酯价/酸价比值可作为反映氧扩散速度是否满足氧化动力学速度的需要,也可以估计氧化所能达到的最高酸价。氧化过程中物料收率变化的规律说明,在反应后期氧化蜡收率的显著降低,与此时CO_2和冷凝水相的生成速度迅速增加有关。氧化至酸价400以上后,C_4～C_（10）二元酸的收率最高可达40％（对原料石蜡）。从色谱分析结果得知,在C_4～C_（10）的单体二元酸分布中,一般皆以丁二酸为最多,次为戊二酸,并且C_4～C_5和C_6～C_（10）二元酸的收率相近。     

改性对β分子筛酸性的影响

考察了处理溶液的pH值及水蒸气分压对β分子筛酸性的影响,发现水蒸气处理后,样品的酸密度减小;随着水蒸气分压的增大,样品的酸密度持续降低;酸碱性处理时,在pH＞7的条件下,样品的酸密度基本保持不变;pH≤7的情况下,酸密度随pH值的减小一直呈下降的趋势;β分子筛经水蒸气处理或酸碱性处理后,B酸的相对含量减小,说明分子筛表面的B酸经过改性可转化为L酸.     

碳化硼粉末和涂层氧化特性研究

本文研究了碳化硼粉末和等离子喷涂碳化硼涂层的相组成及空气中氧化增重特性。试验结果表明，碳化硼粉末和涂层氧化增重均随温度增加而增加，并呈指数变化，氧化过程为热激活过程，激活能分别为９．６ｋＪ／ｍｏｌ和６．３ｋＪ／ｍｏｌ。导致它们氧化增重行为差异的主要原因是粉体和涂层相组成的差别。电子探针分析结果表明，氧化后碳化硼粉末和涂层的结构和形貌均发生明显变化。     

Unraveling the spatial distribution of the acidity of HZSM-5 zeolite on the level of crystal grains

Here we developed a new method to quantitatively characterize the spatial distribution of the Brønsted acidity of HZSM-5 zeolite on the crystal grains level indirectly. The Brønsted acid sites of HZSM-5 zeolite completely covered or blocked by previous coke deposition were released gradually from the outer surface to the center of the crystal grains via shrinking core mode isothermal oxidation with high temperature and low oxygen concentration. The spatial distribution of the coke was obtained based on the one-dimensional position coordinate L_rp through building and solving an enhanced shrinking core model. Then the released acidity characterized by n-propylamine temperature-programmed decomposition was correlated to the specific position of L_rp. The results show that the acid density is roughly homogenous while the acid strength is heterogeneous within the crystal grains. From the outer surface to the center of the crystal grains, the strength of the Brønsted acid sites increase gradually.     

HNO3氧化褐煤制取黄腐酸

用硝酸氧化寻甸褐煤制得氧化褐煤，用含水１０％的丙酮萃取黄腐酸。考察了ＨＮＯ_３浓度、氧化时间及煤酸比对黄腐酸收率的影响。对氧化褐煤和黄腐酸进行了工业分析和总腐植酸、游离腐植酸、总酸性基、羧基、酚羟基的测定。结果表明，褐煤经硝酸氧化可大大提高黄腐酸的收率，是生产农用抗旱剂及工业、医药用黄腐酸的有效途径。     

电流密度对电化学氧化后碳纤维表面基团数量的影响

用X射线光电子能谱(XPS)研究了粘胶基碳纤维在不同电流密度条件下氧化后表面基团的变化规律。结果表明,增加电化学氧化中的电流密度,可以增加碳纤维表面羟基和羟基类基团的数量,羰基的数量则随着电流密度的增加逐渐减少。纤维表面含氧基团总数随着电流密度的增加逐渐增加,达到一定数量后随着电流密度增加含氧基团总数不再明显增加。     

Preparation of active carbons from coal Part II. Carbonisation of oxidised coal

Four coals differing in origin, volatile matter (VM) content, plastic properties and degree of preoxidation have been carbonised in nitrogen up to 1123 K. VM and oxygen contents of the chars obtained from unoxidised coals are very low. The VM content of the chars generally increases with an increase in the degree of coal preoxidation but the oxygen content increases only at lower degrees of preoxidation. While the mercury density of the chars decreases, the helium density increases with the degree of coal preoxidation and is related almost linearly to the helium densities of the oxidised coals. Preoxidation of coal also influences the pore size distribution of chars. The pore size distribution, which is more favourable to macropores in the case of chars obtained from unoxidised coal, becomes more and more in favour of micropores as the degree of coal preoxidation is enhanced. The percentage of micropores increases from 30% to more than 70% after coal preoxidation. Unoxidised coal chars adsorb an insignificant amount of nitrogen at 77 K while an appreciable amount of CO₂ is adsorbed at 273 K. The large difference between N₂ and CO₂ adsorption on chars prepared from coals with low oxidation degree becomes smaller as the degree of coal preoxidation increases. There is a linear relationship between the total pore volume of the char and that of the corresponding oxidised coal, indicating that the chars produced by carbonisation of oxidised coal retain fingerprints of the pore structure of the precursor oxidised coal.     

煤焦氧化对其结构和气化行为的影响

采用固定床反应器对煤焦进行部分氧化处理,然后测定氧化后煤焦在水蒸气和CO2中的气化行为,并用SEM,XRD和N2/CO2吸附对煤焦结构进行表征.结果表明,煤焦低温氧化处理可以显著改善煤焦的孔隙结构,大幅增加比表面积,降低煤焦的有序化和石墨化程度,从而提高其气化活性;并且随氧化程度( burnout)增加,煤焦气化活性不断增加.随氧化温度升高(＞600℃),氧化过程逐渐过渡到扩散控制,O2主要在煤焦外表面反应,因而氧化几乎不会改变煤焦的结构,表面积略有增加,对其后续气化活性无明显影响.