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991.
992.
Spill fires are common during oil product storage and transportation after a loss of containment. Since the burning fuel is moving and the fuel depth is quite shallow, the burning rate in a spill fire is different from that of a pool fire with a static burning zone. Unlike pool fires, which have been studied for decades and have well-established correlations for burning rate, research on spill fires is inadequate. In this paper, continuously released n-heptane spill fire experiments were conducted on open water surfaces with varying fuel discharge rates. The pool diameters were measured, and the spill fire burning rates were estimated based on a dynamic balance between fuel supply and combustion. The burning rates in n-heptane pool fires from the literature were reviewed and compared with the estimated burning rates in spill fires of the same dimension. The spill fire burning rate was found to be close to that in a pool fire during the initial burning phase but lower than that in a bulk burning pool fire and that in a “fuel-level-controlled” pool fire. The distinction between the burning rates of spill fires and pool fires is explained by the heat balance analysis of the fuel layer. A model for the spill fire burning rate was proposed accordingly. The results calculated with the presented model are closer to the measured data than those calculated with pool fire models. 相似文献
993.
Effects of land use,cover, and protection on stream and riparian ecosystem services and biodiversity
Protected areas are an important part of broader landscapes that are often used to preserve biodiversity or natural features. Some argue that protected areas may also help ensure provision of ecosystem services. However, the effect of protection on ecosystem services and whether protection affects the provision of ecosystem services is known only for a few services in a few types of landscapes. We sought to fill this gap by investigating the effect of watershed protection status and land use and land cover on biodiversity and the provision of ecosystem services. We compared the ecosystem services provided in and around streams in 4 watershed types: International Union for Conservation of Nature category II protected forests, unprotected forests, unprotected forests with recent timber harvesting, and unprotected areas with agriculture. We surveyed 28 streams distributed across these watershed types in Quebec, Canada, to quantify provisioning of clean water, carbon storage, recreation, wild foods, habitat quality, and terrestrial and aquatic biodiversity richness and abundance. The quantity and quality of ecosystem services and biodiversity were generally higher in sites with intact forest—whether protected or not—relative to those embedded in production landscapes with forestry or agriculture. Clean-water provision, carbon storage, habitat quality, and tree diversity were significantly higher in and around streams surrounded by forest. Recreation, wild foods, and aquatic biodiversity did not vary among watershed types. Although some services can be provided by both protected and unprotected areas, protection status may help secure the continued supply of services sensitive to changes in land use or land cover. Our findings provide needed information about the ecosystem service and biodiversity trade-offs and synergies that result from developing a watershed or from protecting it. 相似文献
994.
Emerging conservation challenges and prospects in an era of offshore hydrocarbon exploration and exploitation
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Globally, extensive marine areas important for biodiversity conservation and ecosystem functioning are undergoing exploration and extraction of oil and natural gas resources. Such operations are expanding to previously inaccessible deep waters and other frontier regions, while conservation‐related legislation and planning is often lacking. Conservation challenges arising from offshore hydrocarbon development are wide‐ranging. These challenges include threats to ecosystems and marine species from oil spills, negative impacts on native biodiversity from invasive species colonizing drilling infrastructure, and increased political conflicts that can delay conservation actions. With mounting offshore operations, conservationists need to urgently consider some possible opportunities that could be leveraged for conservation. Leveraging options, as part of multi‐billion dollar marine hydrocarbon operations, include the use of facilities and costly equipment of the deep and ultra‐deep hydrocarbon industry for deep‐sea conservation research and monitoring and establishing new conservation research, practice, and monitoring funds and environmental offsetting schemes. The conservation community, including conservation scientists, should become more involved in the earliest planning and exploration phases and remain involved throughout the operations so as to influence decision making and promote continuous monitoring of biodiversity and ecosystems. A prompt response by conservation professionals to offshore oil and gas developments can mitigate impacts of future decisions and actions of the industry and governments. New environmental decision support tools can be used to explicitly incorporate the impacts of hydrocarbon operations on biodiversity into marine spatial and conservation plans and thus allow for optimum trade‐offs among multiple objectives, costs, and risks. 相似文献
995.
为客观掌握油气管道生产运营岗位主要作业风险,实现油气长输管道企业作业风险管理,提出一种作业分级定量风险评价方法。首先,辨识油气管道系统主要危险作业类型和引起作业事故的危险有害因素;然后由作业分级法确定事故发生的可能性与严重性;最后建立基于作业分级的风险矩阵,得到各作业活动的风险级别。将该方法应用于某管道公司,以该公司生产区内部高处作业为例,对作业过程中的危险有害因素进行识别与评价,得出高处作业过程中各步骤的风险程度。结果表明该评价方法具有一定的可操作性,可反映各类危险作业过程中的风险程度,为后期有针对性的风险控制提供指导,有助于公司的风险管理。 相似文献
996.
为保障成品油站场工艺管道的安全平稳运行,在充分辨识风险因素的前提下,提出了一种基于KENT法和RBI的风险评价方法。首先,以风险机理分析为基础,采用SHEL模型从导致风险上升的直接原因(风险内因)和间接原因(风险外因)2个角度辨识了风险因素,并细化各因素指标项;然后借鉴KENT法,对各指标项进行评分量化;依据RBI法,采用风险外因体系修正风险内因体系的方式确定失效可能性;综合环境后果、人员后果与商业后果,明确失效后果的评价体系与计算方法;最后,结合失效可能性与失效后果进行风险评价,从风险等级和风险排序2方面为检维修决策提供依据。应用表明:该评价方法便于工艺管道风险评价的基层实施,可为基于风险的检维修决策提供有效技术支撑。 相似文献
997.
为了探究隔离球在大落差原油管段投产过程中的影响作用,以某大落差“U”型起伏原油管线为实际案例(其最大高差达1 490 m),基于OLGA多相流瞬态模拟方法,对大落差原油管段油顶水过程进行仿真研究。分析隔离球对原油顶水过程中的混油影响,同时对不同输量、管内积液量条件下隔离球在大落差管段中的运动特性进行研究,得到了清管器的平均运行速度、管中压力、持液率的变化趋势以及清管过程中的段塞行为等。结果表明:当输量为900~2 500 m3/h时,隔离球的加入能够降低混油量84.2%~93.7%;同时,还能减少投产过程中由于油品轻质组分汽化所产生的气体,并将更多管内气体带走,减少管中段塞流,提高原油投产效率,为工程实际投产过程提供有效依据。 相似文献
998.
以某陆上原油长输管道为例,设定了陆上原油长输管道泄漏爆炸事故情景背景信息及演化过程,从预防、准备、预警、响应、恢复等阶段,梳理分析了事故情景应对全过程的任务及职责主体;针对各项任务从计划预案、人员队伍、装备物资、培训演练、运行机制等方面开展了情景应对能力评估;并针对存在的差距和不足,从企业和政府2个层面提出了针对此类情景的应急能力提升对策建议。该研究可为相关政府及企业加强油气长输管道事故应急准备能力建设提供参考。 相似文献
999.
西南部分地区麻疯树种子油的理化性质及脂肪酸组成分析 总被引:20,自引:6,他引:20
从西南6个地区采集了麻疯树种子并分析比较了其生物学性状和种子油的理化性质及脂肪酸组成.所有样品的百粒重范围为41.80~71.39g,出仁率60.02%~81.43%,种仁含油率51.76%~57.93%,种子含油率31.07%~47.17%,不饱和脂肪酸含量74.89%~79.68%.其中永胜产麻疯树的种子品质最好,其出仁率为81.43%,种仁含油率57.93%,种子含油率47.17%,不饱和脂肪酸含量79.68%.攀枝花和宁南产麻疯树的种子品质次之.双柏和罗甸麻疯树的种子油酸值为0.81,在所有样品(0.81~9.46)中最低.对麻疯树种子及种子油性质的相关数据进行方差分析,结果表明,产地不同,麻疯树种子的生物学性质、种子油理化性质和脂肪酸组成都有一些差异.图2表3参18 相似文献
1000.
通过室内放水冲刷试验,结果表明,陡坡单宽径流能耗与单宽径流产沙率之间存在以下线性关系:Dr=18.672(ΔE - 0.751),说明土壤的可蚀性参数为18.672 g/J,发生坡面细沟侵蚀的临界径流能耗为0.751 J/(ms)。坡面单宽径流能耗随流量增大而增加,随坡度变化呈抛物线趋势,临界坡度出现在21和24之间。坡面上各段面单宽径流能耗均随流量的增大而增加,随着坡度逐渐增加,坡面上部段面能耗渐增,中部段面渐减,下部较稳定。坡面各段面侵蚀产沙也有类似特征。此研究对于深入了解黄土高原陡坡土壤侵蚀过程和机理具有重要意义。 相似文献