炼油企业低温热大系统优化利用技术

SYSTEMS OPTIMIZATION TECHNOLOGY FOR UTILIZATION OF LOW-TEMPERATURE HEAT IN OIL REFINERY

低温热利用是当前我国炼油企业节能的重要潜力之一。但是随机、分散的利用方式使它们难以得到充分利用。在当前装置大型化、集中布置、开工周期延长控制、设备技术改进条件下,按照"温度对口,梯级利用"的科学用能原则,开发了一种在热出料和装置用能优化的基础上,在全局范围内进行低温热的大系统优化匹配的技术。以循环除氧软水为热媒,按温位高低,集成各种低温热源,再按温位高低顺序用于分馏塔再沸器、储运系统、锅炉给水等低温热阱。使工艺余热得以充分利用,节省了大量加热蒸汽。提出了以最优传热温差为决策变量,热媒水分别与热源、热阱换热的两个网络合成技术,列出了系统的设计方法,给出了实用的案例。

The utilization of low-temperature heat is one of important means for energy conservation of oil refineries in China. The stochastic and dispersive use of low-temperature heat results in serious losses of energy. At current conditions of that the refinery process units become increasingly larger and are arranged in the compact area, the operation cycle is extended, and state-of-the-art technologies are applied for process control and equipment, a refinery-wide low-temperature heat utilization optimization system has been developed on the basis of ＂Step Use by Temperature Grade＂ principle. The low-temperature heat resources are integrated using recycle de-aerated soft water as heat media and based upon their temperature grades, and then used in the lowtemperature sinks in reboilers of fractionator, oil storage and transportation facilities and boiler feed water system, etc. based upon their temperature levels. This makes it possible to fully utilize the waste heat and save a large amount of steam. Two heat exchange train optimization technologies and system design techniques are presented and application cases are given.