Abstract Turnaround operations (start-up and shutdown) are critical operations in olefin plants, which emit large quantities of VOCs, NOx and CO. The emission has great potentials to impact the ozone level in ozone nonattainment areas. This study demonstrates a novel practice to minimize the ozone impact through coordinated scheduling of turnaround operations from multiple olefin plants located in Houston, Texas, an ozone nonattainment area. The study considered two olefin plants scheduled to conduct turnaround operations: one start-up and one shutdown, simultaneously on the same day within a five-hour window. Through dynamic simulations of the turnaround operations using ASPEN Plus Dynamics and air quality simulations using CAMx, the study predicts the ozone impact from the combined effect of the two turnaround operations under different starting-time scenarios. The simulations predict that the ozone impact from planned turnaround operations ranges from a maximum of 11.4 ppb to a minimum of 1.4 ppb. Hence, a reduction of up to 10.0 ppb can be achieved on a single day based on the selected two simulation days. This study demonstrates a cost-effective and environmentally benign ozone control practice for relevant stakeholders, including environmental agencies, regional plant operators, and local communities.

中文翻译：

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通过协调安排臭氧未达标地区的多个烯烃工厂的周转操作来最小化臭氧影响

摘要 检修作业（启动和关闭）是烯烃装置的关键操作，会排放大量的 VOCs、NOx 和 CO，其排放对臭氧未达标地区的臭氧水平有很大影响。这项研究展示了一种通过协调调度位于德克萨斯州休斯顿的多个烯烃工厂的周转操作来最大限度地减少臭氧影响的新做法，这是一个臭氧未达标地区。该研究考虑了计划进行周转操作的两个烯烃工厂：一个启动和一个关闭，在 5 小时窗口内的同一天同时进行。通过使用 ASPEN Plus Dynamics 的周转操作动态模拟和使用 CAMx 的空气质量模拟，该研究预测了在不同启动时间情景下两次周转操作的综合影响对臭氧的影响。模拟预测，计划周转操作对臭氧的影响范围从最大 11.4 ppb 到最小 1.4 ppb。因此，根据所选的两个模拟日，一天最多可以减少 10.0 ppb。该研究为相关利益相关者（包括环境机构、区域工厂运营商和当地社区）展示了一种具有成本效益且对环境无害的臭氧控制实践。