碳钢在含硫介质中的极化行为

采用原油罐罐底水为介质,测定了不同含硫量、PH值以及不同温度下碳钢的极化曲线,分析了各因素对碳钢极化行为的影响。研究结果表明:碳钢在硫含量大于0.2g·L～（-1）、PH值大于9以及一定电位下处于钝化状态,腐蚀电流小;较高温下将大大加速碳钢的腐蚀。     

Rapid determination of formaldehyde and sulfur dioxide in food products and Chinese herbals

Simple, sensitive and rapid methods for the determination of formaldehyde and sulfur dioxide were developed. The formaldehyde determination is based on the reaction between formaldehyde and acetylacetone solution, producing yellow 3,5-diacetyl-l-1,4-dihydrolutidine. Sulfur dioxide was detected as the deoxidize of sulfurous acid by zinc in acidic medium, which produces sulfureted hydrogen that make lead acetate paper blackening due to lead sulfide formation. The detection limits were 0.8 μg mL⁻¹ and 6.0 μg mL⁻¹ for formaldehyde and sulfur dioxide, respectively. The linear range were 0.8–20.0 μg mL⁻¹ for formaldehyde and 6.0–100.0 μg mL⁻¹ for sulfur dioxide determination. The main advantages of the new analytical procedure are the low background level, high selectivity, and very little sample preparation for on-site analysis of formaldehyde and sulfur dioxide in food or Chinese herbal samples with reference color card for qualitative or semi-quantitative determination. The results from these methods correlated well with those obtained from the standard methods.     

Sulphur poisoning of nickel-based hot gas cleaning catalysts in synthetic gasification gas II. Chemisorption of hydrogen sulphide

The effect of different components of gasification gas on sulphur poisoning of nickel catalysts were studied. In addition, the sulphur distribution and content of nickel catalyst beds were analysed to account the poisoning effect of sulphur on the activity of catalysts to decompose tar, ammonia and methane. The desorption behaviour of chemisorbed sulphur from the bed materials was monitored by temperature programmed hydrogenation (TPH). It was established that bulk nickel sulphide was active in decomposing ammonia in high-temperature gasification gas-cleaning conditions. The decomposing activity of methane was not affected by bulk nickel sulphide formation, but that of toluene was decreased. The activity of the catalyst regained rapidly when H₂S was removed from the gas. However, the conversion of ammonia was not regained at as high a level as before sulphur addition, most probably due to irreversible sulphur adsorption on the catalyst. The temperature increase could also be used to regenerate the catalyst performance especially in respect to methane and toluene. Sulphur adsorbed on nickel catalysts in different chemical states depends on the process conditions applied. At >900°C the sulphur adsorbed on the catalyst formed an irreversible monolayer on the catalyst surfaces, while at <900°C the adsorbed sulphur, probably composed of polysulphides (multilayer sulphur), was desorbed from the catalyst in sulphur-free hydrogen containing atmosphere. However, a monolayer of sulphur still remained on the catalyst after desorption. The enhanced effect of high total pressure on sulphur-poisoning of nickel catalysts could be accounted for the increased amount of sulphur, probably as a mode of polysulphides, adsorbed on the catalyst.     

Sensorial Contribution and Formation Pathways of Thiols in Foods: A Review

Since the mid-1990s, more than 300 publications have been devoted to the organoleptic relevance of thiols in foods (meats, wines, fruits). The available data about their physicochemical and sensorial properties, occurrence in foods, and potential formation pathways are compiled in this article.     

浅谈燃煤电厂脱硫与环保

能源开发利用会对环境产生不同程度的不利影响,燃煤电厂排放出的二氧化硫就是污染大气的主要有害物质之一,我国能源环境问题已成为急需解决的现实和战略问题。随着环境保护作为基本国策来推进,电力行业成为二氧化硫削减的主战场,尤其是燃煤电厂,脱硫技术得到了快速的发展。分析了几种火电厂烟气脱硫常用的方法及特点,介绍了古交电厂应用脱硫技术,使一期工程各项指标达到设计要求,脱硫率大于90%,预计二期工程脱硫率大于95%,符合环保要求。     

Effect of tube size on performance of a fixed-film tubular bioreactor for conversion of hydrogen sulfide to elemental sulfur

A fixed-film continuous-flow photobioreactor was used for the removal of hydrogen sulfide from synthetic industrial wastewater and conversion of it to elemental sulfur using sixteen 150 mm length Tygon tubes as the active part of the reactor. Three different tube sizes (internal diameters (ID) 6.4, 3.2, and 1.6mm) were used to investigate the effect of tube size on reactor performance. The reactor with 1.6mm tube attained a higher sulfide loading (1451 mg/Lh) than previously reported in the literature. High bacterial concentration, light to volume ratio and intimate contact between attached bacteria and influent sulfide resulted in excellent performance of the 1.6mm tube reactor.     

罗河铁矿石浮选药剂制度优化

罗河铁矿在以往选硫试验中采用硅酸钠作为分散剂,实际生产中不但加大了选硫药剂投入,还使得最终尾矿难以沉降。为此,进行了罗河铁矿石浮选药剂制度优化研究及验证设计浮选药剂制度试验与优化浮选药剂制度试验的对比。最终在原矿有效硫含量为6.0%的前提下,验证设计浮选药剂制度试验获得了有效硫含量为39.27%、有效硫回收率为70.12%的硫精矿;通过对浮选药剂制度优化后,不加硅酸钠获得了有效硫含量为35.05%、有效硫回收率为77.87%的硫精矿。试验结果表明:加硅酸钠与不加硅酸钠对选别指标的影响不大,故可取消此药剂,达到了节能降耗的目的,经济效益显著。     

某复杂难选铜铅锌多金属硫化矿选矿试验

辽宁葫芦岛地区某金、银品位较高的铜铅锌多金属硫化矿石结构构造复杂,铜、铅、锌分离难度较大。为高效开发利用该矿石,按优先混浮铜铅-混浮精矿铜铅分离-混浮尾矿抑硫浮锌的原则流程对该矿石进行了系统的选矿试验。结果表明,采用2粗1扫2精铜铅混浮、1粗2扫3精铜铅分离、1粗2扫2精选锌、中矿顺序返回的闭路流程处理该矿石,最终获得了铜、金、银品位分别为20.88%、2.37 g/t、1 808 g/t,铜、金、银回收率分别为85.72%、46.27%、22.46%的铜精矿,铅、金、银品位分别为63.13%、0.99 g/t、5 973 g/t,铅、金、银回收率分别为80.00%、19.57%、75.16%的铅精矿,锌、金、银品位分别为55.96%、0.35 g/t、37.80 g/t,锌、金、银回收率分别为84.21%、10.47%、0.72%的锌精矿,较好地实现了铜、铅、锌的分离回收。     

立磨机在某硫精矿中回收锌的应用

从立磨机的结构和工作原理入手,介绍了立磨机在云南某大型硫精矿再磨提锌的应用情况。硫精矿入磨粒度-74μm占80%,产品粒度-45μm占90%,磨矿产品经三次精选达到含锌43%、含铅7. 5%,锌回收率55%、铅回收率18%的合格混合精矿,实现明显的经济效益。