长江口南槽水域营养盐分布特征

通过对长江口南槽水域营养盐时空变化的研究表明,南槽水域营养盐主要以硝酸盐为主,分布比较稳定;垂向分布特征明显,其中NH3N和NO-3N由表层到底层呈下降趋势;无机氮盐在小潮时含量较高,并且受涨落潮影响较小,总磷大潮时含量较高,受涨落潮影响较大;一个潮周期内营养盐的波动范围较小;营养盐的含量与水样中含沙量以及盐度的相关系数较低。     

加热方式对固体废物水分含量测定的影响研究

通过条件实验确定烘箱加热法的恒重条件,确定微波加热法、红外加热法和烘箱加热法测定固体废物水分含量的最佳样品称取量.采用3种方法的最佳条件分别测定了10余种不同类型的固体废物的水分含量,比较了3种方法的测定时间、精密度和测定值的差异性.结果表明:烘箱加热法的最佳恒重条件为前后2次测定差值不超过最终测定质量的±0.1％.烘...     

中国北方地区采暖期颗粒物污染现状

分析了2013—2016年冬季采暖期与非采暖期中国北方地区颗粒物污染现状及时空变化特征。结果表明:中国北方地区空气污染比较严重,采暖期尤为突出。2016年,中国北方地区重度及以上污染天数比例超过10%,采暖期优良天数比例较非采暖期下降22.8%,重度及以上污染天数比例升高10.1个百分点。颗粒物浓度呈现明显的冬季高、夏季低的特点,最高值一般出现在12月至次年1月,最低值一般出现在7—9月。2013—2016年,北方地区空气质量呈较为明显的改善趋势,PM_(10)和PM_(2.5)浓度总体呈下降趋势,但2014年以来采暖期同期比较显示,PM2.5浓度呈缓慢升高趋势,采暖期空气污染形势十分严峻。颗粒物浓度呈现明显的空间分布规律,采暖期石家庄、保定、衡水、邢台、邯郸、安阳等城市为京津冀区域污染最严重的城市。     

长江口南通地区饮用水源地健康风险评价

对长江口南通地区饮用水源地中镉、砷、六价铬等有毒有害物质的浓度进行了调查,并应用目前美国环保局推荐的健康风险评价模型对各饮用水源地有毒有害物质所引起的健康风险做了初步评价。结果表明,长江口南通地区饮用水源地通过饮水途径基因毒物质中化学致癌物所产生的健康风险的数量级为10^-8~10^-5,其中As 在如海河和新通扬运河所引起的致癌风险最大,高于国际辐射防护委员会(ICRP) 推荐的通过饮水途径最大可接受风险水平;通过饮水途径引起的非致癌健康风险远低于ICRP 推荐的最大可接受风险水平。基因毒物质中砷和六价铬这2种毒物应被列为该地区饮用水源地水和水厂制水过程中优先检测和控制的致癌污染物,应重点关注基因毒物质六价铬和砷对人体所产生的健康风险。     

轻烃回收装置大检修动火风险管控措施探讨

针对轻烃回收装置火灾爆炸事故大部分发生在维检修阶段的现象,通过结合生产实际,提出采用动火前施工工序确认制度,严控高风险点位,避免"立体交叉"动火作业等措施,杜绝经验主义和侥幸心理,最大限度避免动火作业着火爆炸事故的发生。文章介绍了轻烃回收装置的介质特点及主要工艺,分析了轻烃回收装置大检修基本流程及动火风险,提出控制动火施工安全风险的管理实践。     

Resilience-based approach to safety barrier performance assessment in process facilities

The performance assessment of safety barriers is essential to find vulnerable elements in a safety barrier system. Traditional performance assessment approaches mainly focus on using several static indicators for quantifying the performance of safety barriers. However, with the increasing complexity of the system, emerging hazards are highly uncertain, making it challenging for the static indicators to assess the performance of safety barriers. This paper proposes a resilience−based performance assessment method for safety barriers to overcome this problem. Safety barriers are classified according to their functions first. The dynamic Bayesian network (DBN) is then introduced to calculate the availability function under normal and disruption conditions. The ratio of the system's availability, when affected by the disruption, to the initial availability, is used to determine the absorption capacity of the system. The ratio of the quantity of availability recovery to the total quantity of system represents the adaptation and restoration capacity of the system. The system's resilience is represented by the sum of absorption, adaptation, and restoration capacities. The wax oil hydrogenation process is used to demonstrate the applicability of the proposed methodology.     

A new categorization of release models using a semi-analytic solution

The spread of cryogenic liquid due to a limited period of release is investigated for the first time to clarify the unclear conventional concept regarding two release types: continuous and instantaneous release. The physical phenomenon is described by equations involving the volume, radius and height of the liquid pool, and there are three governing parameters: the evaporation rate per unit area, a release time, and a spill volume. As a result of the perturbation solutions, the combined model, which consists of the continuous model and the subsequent instantaneous model, is necessary for a large spill source rate, whereas the continuous model is only required for a small spill source rate. This combined release model is more realistic than the instantaneous release model, and it is shown that the combined model and the continuous model are clearly distinguished in the coordinate system of the release time and the spill volume using the analytical feature of the perturbation solution.     

燃气-蒸汽联合循环供热项目主机选型方案刍议

发展燃气-蒸汽联合循环供热对于解决经济发展和环境保护具有重要作用，在我国经济发达地区已经开始大规模推广。阐述了燃气一蒸汽联合循环发电、供热技术、特点等，对主机选型方案提出建议。     

温和热处理对低有机质污泥厌氧消化性能的影响

以高浓度低有机质污泥为研究对象,通过改变加热时间研究100℃温和热处理对其有机物溶出以及厌氧消化性能影响.结果表明通过100℃的温和热处理,污泥上清液中的有机物浓度在预处理前30 min内显著增加,30 min以后则趋于平缓.其中SCOD、蛋白质和碳水化合物在100℃热处理30 min时的溶出率分别达到10.5%、11.6%和8.2%.温和热处理不仅可以提高低有机质污泥的产气总量,而且还可以缩短产气高峰的到达时间.经100℃热处理30 min的污泥,在厌氧消化10 d时的沼气产率(以VS计)为136.0 mL·g-1,比空白对照组提高了86.0%;厌氧消化30 d后的VS降解率也由空白时的19.1%增加到33.3%.此外,实验结果还表明,100℃的温和热水解处理对厌氧消化过程中的4种关键酶(蛋白酶、乙酸激酶、磷酸转乙酰酶和辅酶F420)均有不同程度的促进作用.     

夏收时段农村大气亚微米颗粒物数浓度分布特征

为了从源区的角度研究华北平原夏收时段大气亚微米颗粒物粒径谱分布,采用扫描电迁移率粒径谱仪,于2017年6月对华北平原典型农村点位亚微米颗粒物数浓度进行连续观测.结果表明,观测期间大气亚微米颗粒物粒径分布主要集中在小于300nm处,平均数浓度为28371cm^-3.不同模态颗粒物数浓度分布差异明显,核模态（< 20nm）呈线性分布,爱根核模态（20~100nm）呈多项分布,积聚模态（>100nm）呈对数分布.48h后向轨迹聚类结果表明,观测点位气团受其东部的江苏省、山东省和安徽省生物质燃烧传输影响时,颗粒物总数浓度增加66.7%.潜在源贡献因子法和浓度权重轨迹法,表明潜在源区为观测点位以东的区域,且以粒径小于100nm的颗粒物为主.