先进控制技术在超大型水煤浆气化装置中的应用

Application of advanced process control technology in ultra-large coal-water slurry gasification plant

煤气化过程由于煤质波动、反应系统复杂及仪表测量滞后,难以及时反映气化炉实时运行状况,使得气化炉运行存在操作保守、响应滞后等问题。针对上述问题,将先进控制技术(Advanced Process Control Technology)应用在气化炉上,有助于实现气化过程的卡边操作,提高装置的运行平稳率并优化空间。国家能源投资集团榆林化工公司3000 t/d水煤浆气化炉已开车成功,完备的测量仪表和可靠的DCS系统使其具有作为先进控制技术实施的基础。以榆林化工公司的超大型水煤浆气化炉作为智能工厂开发实践的切入点,从提高煤气化装置的自控投用率、气化炉数字孪生、多变量协同约束控制3方面介绍先进控制技术在煤气化装置中的应用与研究进展。结果表明:通过回路整定软件PID-GO对1号气化炉系统的35条控制回路进行PID整定,气化装置的优良投用率由44%提高至84%以上,自控投用率由65%提高至91%以上;通过Unisim建立了稳态和动态数字孪生模型。通过稳态模型计算的合成气温度、粗合成气流量及主要气体组分均能与运行值吻合,模拟相对误差小于5%,动态模型捕捉到煤浆流量在1 min内由140 m^(3)/h降至100 m^(3)/h,出现气化温度由1276℃升高至1461℃的短时间超温现象;在仿真平台上实现了多变量协同优化软件PD-Master与Unisim模型的动态链接,通过PD-Master的滚动优化,气化炉的优化变量均达到了既定目标,氧煤比、气化炉温、合成气流量及有效气含量计算值与目标值误差在2.2%以内,其中权重最高的变量C_(V1)和C_(V2)的计算偏差分别为-0.06%和0.11%。

The gasification process is difficult to reflect the real-time operation condition of gasifier in time due to its fluctuation of coal quality,complexity of reaction system and lag of instrumentation measurement,which makes the operation of gasifier often suffer from conservative operation and response lag.To address these problems,the application of advanced control technology(APC)to the gasifier will help improve the smooth rate and optimization space of the gasification unit.The 3000 t/d coal-water slurry gasifier of National Energy Investment Group’s Yulin Chemical Company has been driven successfully,and its complete measurement instrumentation and reliable DCS system make it a basis for implementation as an advanced control technology.The super-large coal-water slurry gasifier of Yulin Chemical Company was taked as the entry point of smart plant development practice,and the application and research progress of advanced control technology was introduced in coal gasification plant from three aspects,namely,improving the self-control commissioning rate of coal gasification plant,digital twin of gasifier and multi-variable cooperative constraint control.Results show that the loop rectification software PID-GO is used to control the 35 control items of No.1.The excellent commissioning rate of the gasification plant is increased from 44%to more than 84%,and the commissioning rate of the automatic control is increased from 65%to more than 91%.The steady-state and dynamic digital twin models are established by Unisim.The syngas temperature,crude syngas flow rate and main gas components calculated by thesteady-state model can match with the operating values,and the relative error of simulation is less than 5%,and the dynamic model captures that a decrease in coal slurry flow rate from 140 m^(3)/h to 100 m^(3)/h within 1 minute results in a short time over-temperature increase in gasification temperature from 1276℃to 1461℃.The dynamic linkage between the multivariate co-optimization software PD-Master and Unisim model is implemented on the simulation platform.Through the rolling optimization of PD-Master,the optimized variables of the gasifier all achieve the established optimization targets,and the calculated values of oxygen-coal ratio,gasifier temperature,syngas flow rate and effective gas content are within 2.2%of the target value,and the deviations of the variables with the highest weights,C_(V1)and C_(V2),are-0.06%and 0.11%,respectively.