从冶炼烟气中回收元素硫

对用天然气还原含二氧化硫气体的硫回收方法进行了半工业试验。在一个旋风反应器内用天然气高温还原二氧化硫,确定基本的工艺参数。根据所获得的参数,在诺里尔斯克冶炼厂工业装置上用该法处理自热熔炼炉烟气。工业运行结果证实了所提工艺的可行性,对位于偏远地区和不需要硫酸地区的冶炼装置具有一定的吸引力。     

催化裂化多产丙烯

丙烯作为重要的基本有机化工原料, 其市场需求快速增长, 除蒸汽裂解工艺外, 流化催化裂化(FCC)是丙烯生产的另一重要来源。本文主要综述了国内外开发并应用的一系列催化裂化多产丙烯的工艺技术, 着重介绍了各生产工艺技术的特点、产品分布及其工业应用情况, 并从催化剂、操作条件和反应器三个方面对催化裂化多产丙烯的影响因素进行了分析。FCC多产丙烯工艺与常规FCC工艺相比较表明, 丙烯收率均有较明显的提高, 并指出通过FCC工艺技术改造增产丙烯已是重要技术路线。     

生产二氯苯的铁系催化剂硫含量的测定方法

参照氧化法的分离途径在空气流中高温灼烧样品，将生成的二氧化硫气体用过氧化氢溶液吸收、氧化成硫酸。该种方法简便、快速、精密度高，可以在短时间内准确地测定铁系催化剂中的硫含量，有效避免了铁、钠、氯等元素的干扰。     

Transition metal/fluorite-type oxides as active catalysts for reduction of sulfur dioxide to elemental sulfur by carbon monoxide

Reduction of SO₂ by CO to elemental sulfur on fluorite oxide and transition metal/fluorite oxide composite catalysts is discussed within the redox framework. The oxygen vacancies on the fluorite oxide are active catalyst sites and their creation is a key step to initiate the redox reaction. Transition metal/fluorite oxide composites demonstrate a strong synergism for the reaction. A reduction kinetics study of the copper/ceria system as a model composite catalyst has found that surface oxygen is highly active but its activity is inhibited by SO₂ adsorption. The TPR profile of the copper/ceria catalyst shows a significantly lower reduction peak than the individual components.     

Influences of surface functional groups on catalytic activity over activated carbon catalysts for sulfur dioxide removal from flue gases

The catalytic oxidation of sulfur dioxide in flue gases over activated carbon catalysts was studied. Catalysts made from different materials or by different methods were markedly different. The catalysts were characterized by BET isotherms and X-ray power diffraction. The acidic and basic sites and/or strength on the catalysts were determined by temperature-programmed desorption, while surface functional groups were determined by X-ray photoelectron spectroscopy. The catalytic activity depended on oxygen-containing surface functional groups with Brønsted basicity properties. These groups on a furfural residue activated carbon could be increased by a suitable treatment to enhance the catalytic activity but other catalysts in this study showed no activity enhancement with a similar treatment.     

A model for the release of sulfur from elemental S and superphosphate

A mathematical model was developed to predict the release of sulfate from elemental S (S⁰) and gypsum in single superphosphate. The release algorithm is based on the observation that release is linearly related to particle surface area. Release rates under various conditions could then be described by the change in radius for each time increment, which allows easier comparison of release rates between different particle sizes. A model based on spherical particles was found to be adequate in accounting for the range of particle shapes found in crushed agricultural S⁰. Release rates calculated from experimental data range from 0.07 to 0.45µm/d depending on environmental conditions.Equations for incorporating the effects of environmental variables and the release of S from S⁰ and from the gypsum component of single superphosphate (SSP) were developed from the literature, and were incorporated within a larger model of S cycling. The model predicted that after 72 days, 99% of the S in SSP would have been released, compared to a release after one year of 54% of the S in sulfur-fortified superphosphate, and 23% of that in crushed agricultural grade S⁰. The model provides a means of assessing the effect of the particle size of S⁰ on release rates and should allow the formulation of fertilizers that supply S at a rate closer to the rate of plant uptake.     

Plant for the production of activated carbon and electric power from the gases originated in gasification processes

The development of the countries involves a high energy demand; however, the energetic resources used by the moment are not renewable. Events like the energetic crisis of 1973, the continuous geopolitic clashes in energetic resource-rich areas, and the global environmental deterioration as a consequence of the industrial activity taking place in last century, make obvious the need of searching new sources of energy [1].One of these sources is the obtainment of energy from biomass exploitation. The use of this raw material involves advantages in the emission of low quantities of contaminants to the atmosphere and its renewable character. Until now, the main drawback of this source is its lack of viability when trying to obtain electric power from biomass, due to the use of systems composed of a boiler and a steam turbine (which offer low operative flexibility), which are not rentable in such a competitive market as it is, currently, the energetic one. Nowadays, the use of internal combustion engines, combined with biomass gasifiers, allows rapid connection–disconnection of the plant (aproximately of five minutes), which confers a big flexibility to the system and, as a consequence, a better exploitation of the plant in maximum energetic consumption hours. It also has the advantage of establishing a co-generation system since the gases are generated at a high temperature, 800 °C [2].With this view, the aim of this work has focused in the re-design of a gasification plant for the production of activated carbons, from biomassic residues, for the energetic exploitation of the combustible gases produced during the pyrolytic process (H₂, CO, CH₄, C₂H₂, C₂H₄, C₂H₆), since these gases are currently burnt in a torch in the plant. The idea of designing the activated carbon production plant arose from the need of managing the biomass residues (olive wastes) generated by the firm Euroliva-Azeites e Oleos Alimentares SA, located in Alto Alentejo, in the city of de Vale do Peso, Concelho de Crato. This firm collects the residues produced in the olive oil mill of Concelho do Crato and then, in the plant, makes the last obtainment of less-quality olive oil, which gives rise to a high production of olive waste. The production of this residue is 250 tons/day, which involves an annual production of 87,500 tons of residues that have to be removed [3]. The activated carbon production plant, already built, has a processing capacity of 250 kg h^− 1 of residual biomass, with a yield close to 16% in carbon production. According to the plant capacity and the generated gases potential, a thermal power of 1.05 MW and, considering a process global output of 25%, an electric power of 250 kW would be obtained.     

Selective oxidation of H2S to elemental sulfur over chromium oxide catalysts

CrO_x and CrO_x supported on SiO₂ have been found to be active for the selective oxidation of hydrogen sulfide to elemental sulfur. The catalysts show maximum sulfur yield at a stoichiometric ratio of O₂/H₂S, 0.5. Amorphous Cr₂O₃ exhibits higher yield of sulfur and has stronger resistance against water than supported Cr/SiO₂, especially at low temperatures. At high temperatures above 300°C, the sulfur yield over the supported catalyst becomes similar to amorphous Cr₂O₃ because the Claus reaction occurring on the silica support removes SO₂ to increase the sulfur yield. Active sites are the amorphous monochromate species that can be detected as a strong temperature programmed reduction (TPR) peak at 470°C. Catalytic activity can be correlated with the amount of labile lattice oxygen and the strength of Cr–O bonding. The reaction proceeds via the redox mechanism with participation of lattice oxygen.     

The synthesis of MMA-S copolymer starting from PMMA and elemental sulfur

Summary The synthesis of methylmethacrylat (MMA) — sulfur copolymer has been completed by starting from a mixture of Polymethylmethacrylat (PMMA) temperature (360°C) by using a specially designed reaction vessel. The formation of copolymer is spontaneous and is due to the presence of active species (free biradical of MMA and S) generated through the decomposition of PMMA and polysulfur under extreme conditions.The resulted copolymer has been characterized by using elemental analysis, IR, NMR and MS spectroscopy.     

微生物法处理含硫工业废气

指出了含硫工业废气传统处理方法的缺陷 ,介绍了微生物处理方法的优势所在 ;对微生物菌种的共同特征以及无机硫和有机硫脱除时菌种的选择依据进行了讨论 ,并对微生物法脱硫的机理进行了分析 ;评述了国内外生物滤池法、生物滴滤池法和生物吸收法等生物膜法脱硫的工艺及其工业化应用。指出了微生物法脱硫技术有待深入研究的问题、发展趋势和应用前景。     

综述与展望 丙烷直接氨氧化制丙烯腈生产工艺及催化剂研究进展

概述丙烯腈的生产方法及特点,分析丙烷直接氨氧化生产丙烯腈的工艺特点和优势,对丙烷直接制备丙烯腈的催化剂体系Sb-V-O催化剂、Mo-V-Te-Nb-O催化剂、钒-铝氮氧化物及分子筛类催化剂等进行介绍,并建议我国尽快实现以丙烷为原料生产丙烯腈。     

Reaction of elemental sulfur in ethylenediamine with sulfur mustard

Reaction of elemental sulfur in ethylenediamine with 1,1-thiobis(2-chloroethane) or sulfur mustard, the potent chemical warfare agent has been studied. The optimum conditions for the reaction are established for the complete conversion of sulfur mustard into non-toxic products. The above reaction has been successfully converted into a technology for chemical destruction of sulfur mustard (patented in USA, Russia, Germany and India).     

元素硫磺与作为硫化剂使用的聚乙烯相互作用后的高含硫产物

文章介绍了在高温作用下,以及在2-MBT与DPG参加下低压聚乙烯与元素硫磺反应产物的合成工艺过程。把新合成的添加剂作为硫化剂加入EPDM-70胶料中并进行了应用研究。结果表明,含硫量超过80%的合成添加剂为高效硫化剂。它可以使橡胶的正硫化温度有所降低,并且能赋予橡胶一系列良好的流变性能和力学性能。     

Catalytic processes for the production of hydrocarbon biofuels from oil and fatty raw materials: Contemporary approaches

The scientific and technical achievements made during the last 15 years in the deoxygenation processes for the production of hydrocarbon biofuels from oil and fatty raw materials are reviewed. The most advanced methods for the processing of triglycerides into hydrocarbons are associated with the use of pyrolysis, catalytic cracking, and hydrotreatment processes similar to those already used at petrochemical plants and oil refineries. The hydrotreatment technologies, which have already been adopted or ready for industrial application, are considered in more details. Nonsulphide catalysts for the single-stage production of waxy diesel fractions from vegetable oils and combined technologies are promising for reducing the consumption of hydrogen and increasing the yield of hydrocarbon products and the flexibility in obtaining different types of fuel.     

Copolymerization of elemental sulfur with styrene

Copolymerization of elemental sulfur with styrene in the presence and absence of metallic sodium was studied at 120°C and 138°C. Propagation of the reaction was followed by gel permeation chromatography (GPC). Glass transition temperatures of all samples were obtained by differential scanning calorimetry (DSC). Reaction products were fractionated with a preparative-type GPC, and each fraction was characterized by DSC, vapor pressure osmometry, infrared spectrophotometry, and both proton and carbon-13 nuclear magnetic resonance spectrometry. Results indicate that the product is a true copolymer of styrene and sulfur. Kinetics of the copolymerization were studied using GPC to monitor styrene and sulfur concentrations. The initial rate of copolymerization (as followed by the consumption of styrene and sulfur) decreases with increasing initial styrene to sulfur ratio. From kinetic analyses, ratios of the rate constants of homo- and copolymerization were determined. Copolymerization of the reactants is more spontaneous than homopolymerization. The reactivity ratios obtained are 0.2 for styrene and 0.6 for sulfur.     

Catalytic reduction of sulfur dioxide using hydrogen or carbon monoxide over Ce1−xZrxO2 catalysts for the recovery of elemental sulfur

This study focuses on the direct sulfur recovery process (DSRP), in which SO₂ can be directly converted into elemental sulfur using a variety of reducing agents over Ce_1−xZr_xO₂ catalysts. Ce_1−xZr_xO₂ catalysts (where x = 0.2, 0.5, and 0.8) were prepared by a citric complexation method. The experimental conditions used for SO₂ reduction were as follow: the space velocity (GHSV) was 30,000 ml/g_-cat h and the ratio of [CO (or H₂, H₂ + CO)]/[SO₂] was 2.0. It was found that the catalyst and reducing agent providing the best performance were the Ce_0.5Zr_0.5O₂ catalyst and CO, respectively. In this case, the SO₂ conversion was about 92% and the sulfur yield was about 90% at 550 °C. Also, a higher efficiency of SO₂ removal and elemental sulfur recovery was achieved in the reduction of SO₂ with CO as a reducing agent than that with H₂. In the reduction of SO₂ by H₂ over the Ce_0.5Zr_0.5O₂ catalyst, SO₂ conversion and sulfur yield were about 92.7% and 73%, respectively, at 800 °C. Also, the reduction of SO₂ using synthetic gas with various [CO]/[H₂] molar ratios over the Ce_0.5Zr_0.5O₂ catalyst was performed, in order to investigate the possibility of using coal-derived gas as a reducing agent in the DSRP. It was found that the reactivity of the SO₂ reduction using the synthetic gas with various [CO]/[H₂] molar ratios was increased with increasing CO content of the synthetic gas. Therefore, it was found that the Ce_1−xZr_xO₂ catalysts are applicable to the DSRP using coal-derived gas, which contains a larger percentage of CO than H₂.     

热化学碘硫循环制氢流程用硫酸分解催化剂

核能制氢是一种高效、经济和无污染的大规模制氢方法，热化学碘硫（I-S）循环被认为是最有前景的核能制氢工艺，其中硫酸分解步骤是直接利用核热的部分。对硫酸分解催化剂的研究状况进行了综述，归纳比较了金属氧化物、贵金属以及尖晶石和钙钛矿类催化剂对硫酸催化分解的效果；讨论了部分催化剂的催化机理，并结合自己的工作，提出了硫酸分解催化剂的研究开发方向。     

Catalytic hydrogen production from 2-propanol in supercritical water: Comparison of some metal catalysts

The gasification of organics in supercritical water is a promising method for the direct production of hydrogen at high pressures, and in order to improve the hydrogen yield or selectivity, activities of various catalysts are evaluated. In this study, hydrogen production from 2-propanol over Ni/Al₂O₃ and Fe–Cr catalysts was investigated in supercritical water. The experiments were carried out in the temperature range of 400–600 °C and in the reaction time range of 10–30 s, under a pressure of 25 MPa. The hydrogen yields and selectivities of Ni/Al₂O₃ and Fe–Cr used in this study, and those of Pt/Al₂O₃ and Ru/Al₂O₃ used in our previous work were compared. The hydrogen contents of the gaseous products obtained by using Ni/Al₂O₃ and Fe–Cr were measured as 62 mol% and 70 mol%, respectively, at low temperatures and reaction times. However, the hydrogen yields remained in low levels when compared with that of Pt/Al₂O₃ used in previous study. Pt/Al₂O₃ was established to be the most effective and selective catalyst for hydrogen production. During the catalytic gasification of a 0.5 M solution of 2-propanol, hydrogen content up to 96 mol% and hydrogen yield of 1.05 mol/mol 2-propanol were obtained.     

Catalytic oxidation of sulfur and nitrogen compounds from diesel fuel

The oxidation of nitrogen or sulfur pollutants, using organic substrates as model compounds, was monitored with electrospray ionization mass spectrometry. Quinoline, dibenzothiophene and methylene blue were found to be oxidized through a successive hydroxylation mechanism. These results strongly suggest that highly reactive hydroxyl radicals, generated during the reaction of H₂O₂ on the catalyst surface, are responsible for this oxidation, and confirm that the material is an efficient heterogeneous Fenton-like catalyst, which is able to eliminate around 90% of the sulfur molecules. This is, therefore, an important and useful tool for the elimination of refractory sulfur in the hydrotreatment process with potential application to meet future environmental legislation indexes. It is important to remember that only the heteroatom fraction is degraded, preserving the hydrocarbons of interest in the diesel flows. The catalyst showed activity in successive oxidation cycles presenting a high regeneration capacity.     

Catalytic and adsorptive desulphurization of gases

The present paper considers some very important problems: problems which are important in the area of environmental protection, as well as in the technical and technological desulphurization of gases. Here we have selected only those ‘dry’ technologies in which adsorption and catalytic processes occur. The paper presents the basics of methods for removing sulphur dioxide and hydrogen sulphide from what are called acid gases, as well as equipment for this purpose, together with a discussion of the advantages and disadvantages of particular processes. The introduction to the paper includes the sources of the emission of hydrogen sulphide and sulphur dioxide, their toxicity, and the methods by which atmospheric air can be environmentally protected. The writer realizes that the paper does not include all technologies but only the major directions, which make removal of contamination caused by sulphur compounds from tail gases possible. The typical catalytic dry processes of the conversion of sulphur compounds in tail gases represent a new direction, which is likely to undergo intensive development if we are able to solve the problem of the preparation of appropriate catalysts operating under very difficult and unstable conditions.