Mathematical models used to optimize the process plant layout (PPL) with risk reduction have four primary objectives, which are related to the minimization of land, pumping (pipe system), protection system devices, and risk costs. Moreover, these models are of two types: continuous plane models (CPM) and grid-based models (GBM); however, the nonconvexity of the CPM models makes difficult to achieve the global optimum, because it is formulated as Mixed-Integer Nonlinear Programming (MINLP). Thus, the risk map approach has been implemented with the grid-based models to solve problems of process plant layout focused on finding the best possible solution. However, these risk map formulations present important limitations, mainly related with the use of protection devices and the occupied area. Therefore, a new GBM-MILP formulation is proposed to optimize the selection of protection devices and minimize the occupied area. The risk is reduced through the investment on safety devices instead of considering the increase of separation distances. The proposed model was used to solve the layout problem of an ethylene oxide process, and the results was compared with a process layout reported in the literature. The results show that the model can provide the best possible solution; however, the time spent in the calculation is considerably greater than that reported for continuous plane models. Finally, the model can be used by decision-makers to evaluate different layout options for several explosion scenarios, during the early stages of the plant design.

用于通过降低风险来优化过程工厂布局（PPL）的数学模型具有四个主要目标，这些目标与最小化土地，泵送（管道系统），保护系统设备和风险成本有关。此外，这些模型有两种类型：连续平面模型（CPM）和基于网格的模型（GBM）；但是，CPM模型的非凸性使其难以实现全局最优，因为它被表述为混合整数非线性规划（MINLP）。因此，已经使用基于网格的模型实施了风险图方法，以解决集中于寻找最佳解决方案的过程工厂布局问题。但是，这些风险图的表述存在重要的局限性，主要与使用保护装置和占用区域有关。所以，提出了一种新的GBM-MILP配方，以优化保护装置的选择并最大程度地减少占用面积。通过投资购买安全设备来降低风险，而不是考虑增加隔离距离。所提出的模型用于解决环氧乙烷工艺的布局问题，并将结果与​​文献中报道的工艺布局进行了比较。结果表明，该模型可以提供最佳的解决方案。但是，计算所花费的时间比连续平面模型所报告的时间要大得多。最后，在工厂设计的早期阶段，决策者可以使用该模型评估几种爆炸场景的不同布局选项。通过投资购买安全设备来降低风险，而不是考虑增加隔离距离。所提出的模型用于解决环氧乙烷工艺的布局问题，并将结果与​​文献中报道的工艺布局进行了比较。结果表明，该模型可以提供最佳的解决方案。但是，计算所花费的时间比连续平面模型所报告的时间要大得多。最后，在工厂设计的早期阶段，决策者可以使用该模型评估几种爆炸场景的不同布局选项。通过投资购买安全设备来降低风险，而不是考虑增加隔离距离。所提出的模型用于解决环氧乙烷工艺的布局问题，并将结果与​​文献中报道的工艺布局进行了比较。结果表明，该模型可以提供最佳的解决方案。但是，计算所花费的时间比连续平面模型所报告的时间要大得多。最后，在工厂设计的早期阶段，决策者可以使用该模型评估几种爆炸场景的不同布局选项。并将结果与​​文献报道的工艺布局进行比较。结果表明，该模型可以提供最佳的解决方案。但是，计算所花费的时间比连续平面模型所报告的时间要大得多。最后，在工厂设计的早期阶段，决策者可以使用该模型评估几种爆炸场景的不同布局选项。并将结果与​​文献报道的工艺布局进行比较。结果表明，该模型可以提供最佳的解决方案。但是，计算所花费的时间比连续平面模型所报告的时间要大得多。最后，在工厂设计的早期阶段，决策者可以使用该模型评估几种爆炸场景的不同布局选项。