化学化工专业英语试题_化学工程与工艺专业英语阅读教程_化学工程与工艺考教师(59)

4.发电厂排放物的控制

通过燃煤、燃油和燃烧天然气产生能量的设备都会排放出一氧化碳、碳氢化合物、氮氧化物以及许多其它不受欢迎的副产物如灰尘和痕量的汞。现在可以采用一系列不断发展的技术来减少不希望有的物质的排放以适应国家和地区标准的要求。化学家和化学工程师对工业水平的进步做出了巨大的贡献。而催化科学为开辟这些前沿领域正在扮演重要的角色。

Thesimultaneouscontrolofmorethanonepollutantistheaimofsomerecentlydevelopedcatalystorsorbenttechnologies.Forexample,catalyticmethodsallowcarbonmonoxidetobeoxidizedatthesametimethatnitrogenoxidesarebeingchemicallyreducedingasturbineexhaust.Otherresearcheffortsareaimedatpilot-plantevaluationofthesimultaneousremovalofsulfurandnitrogenoxidesfromfluegasbytheactionofasinglesorbentandwithoutthegenerationofmassivevolumesofwasteproducts.

同时控制多种污染物是近年来开发先进的催化剂或吸附剂技术的目的。例如，催化方法可以使汽车尾气中CO氧化的同时，还原氮的氧化物。另一些研究工作则定位于在中试阶段通过一种吸附剂的作用同时去除烟道气中的硫和氮氧化物，而不会产生大量的废物。

EnvironmentallyFriendlyProducts

Increasedunderstandingofthefateofproductsintheenvironmenthadledscientiststodesign“greener”products.Asignificantearlyexamplecomesfromthedetergentindustryinthe1940sand1950s,newproductswereintroducedthatwerebasedonsyntheticsuctantscalledbranchedalkylbenzenesulfonates.Thesedetergentshadhighercleaningefficiency,butitwassubsequentlydiscoveredthattheirpresenceinwastewatercausedfoaminginstreamsandrivers.Theproblemwastracedtothebranchedalkylbenzenesulfonates;unlikethesoapsusedpreviously,thesewerenotsufficientlybiodegradedbythemicrobesinconventionalsewagetreatmentplants.Anextensiveresearchefforttounderstandtheappropriatebiochemicalprocessespermittedchemiststodesignandsynthesizeanothernewclassofsuctants,linearalkylbenzenesulfonateas,.Thesimilarityinmolecularstructurebetweenthesenewcompoundsandthenaturalfattyacidsoftraditionalsoapsallowedthemicroorganismstodegradethenewformulations,andthesimilaritytothebranchedalkybenzenesulfonatesaffordedoutstandingdetergentperformance.