LNG浸没燃烧式气化器温度控制系统研究

Research of the temperature control system of LNG submerged combustion vaporizer

关键词:  LNG  浸没燃烧式气化器  串级控制  Smith预估

Key words:  liquefied natural gas  submerged combustion vaporizer  cascade control  Smith prediction

摘要:

为了解决LNG浸没燃烧式气化器温度控制存在较大滞后的问题,在分析气化器水浴温度特性的基础上,以气化器出口天然气温度为主被控对象,以水浴温度为副被控对象,建立了一种基于串级控制的数学模型。将Smith预估引入串级控制的副回路,将纯滞后引出副环,在主回路再次进行Smith预估补偿,将系统纯滞后移出主环。仿真结果和实际运行验证了该方案控制效果的有效性。

Abstract:

To solve the pure time-delay problem of the temperature control of LNG submerged combustion vaporizer, a mathematical model for temperature cascade control of vaporizer is established after theoretical analysis,based on the analysis of the evaporator water bath temperature characteristic. This model takes the evaporator outlet NG temperature as the mainly control object, and takes water bath temperature as the secondary control object. The vice-return route introduces the Smith prediction to emigrate the pure time-delay from the vice-link, at the same time, the main return route introduces the smith prediction again to overcome the effect of pure time-delay that the vice-return route transfers to the main link vice-return route. The simulation results and the actual operation verify the effectiveness of the scheme.