基于CO_2排放控制的炼厂能量系统改造及其多目标优化

Multi-objective Optimization and Retrofit of Energy Utilization System in a Refinery Based on CO_2 Emission Control

针对炼厂能量利用系统,提出了将换热网络改造与燃料转换相结合的炼厂CO2减排控制方法,建立了年度化改造总费用与CO2年排放总量权衡的多目标优化数学模型,考虑了系统改造的经济性和系统改造所额外增加的CO2排放对系统优化的影响,采用ε约束法获得了Pareto最优前沿。以某炼厂蜡油加氢装置换热网络为例,阐述了所提出方法的实现过程及其效果,获得了CO2年排放量与年度化改造总费用之间的Pareto最优前沿以及CO2年排放总量限制条件下的最优改造策略,为炼厂的CO2减排与控制提供了多目标优化的理论基础。

For energy utilization system in a refinery, strategies combining retrofit of heat exchanger network and fuel switching were proposed to reduce C（）2 emission in the refinery. A multi-objective optimization model that is subject to a trade-off between the total annual costs for retrofit and total annual CO~ emission was developed. In the proposed method, influences of economy for retrofit and its extra CO2 emission were taken into consideration. The Pareto front was obtained through ~ constraint method. The procedure and effects of the proposed approach were exemplified through a heat exchanger network in a wax oil hydrotreating unit. The Pareto front representing the trade-off between total annual costs for retrofit and total annual CO2 emission was obtained, and the optimal retrofit schemes under different annual CO2 emissions were obtained accordingly. The proposed method provides theoretical fundamentals of a multi-objective optimization for CO2 emission reduction in refineries.