CAJ | 학술논문

提出了用精馏塔对含氮天然气脱除N2生产液化天然气（LNG），精馏塔塔釜液位的一种控制方法。该方法以脱氮分离效率和稳定的产品（LNG）出料温度为控制目标，建立了塔釜液位控制模型并仿真。整个闭环控制模型包括被控对象传递函数，调节阀传递函数，PID控制传递函数和检测传递函数。其中调节阀传递函数的建立，采用先计算阀位-Cv值（流量系数）曲线；然后通过系统辨识法[1]求得数学模型；最后利用泰勒级数把非线性化转化为线性化并求得传递函数。通过Matlab软件[2]的仿真，在阶跃干扰下，得到了合适的液位变化曲线和合适的阀位变化[3]。
제출료용정류탑대함담천연기탈제N2생산액화천연기（LNG），정류탑탑부액위적일충공제방법。해방법이탈담분리효솔화은정적산품（LNG）출료온도위공제목표，건립료탑부액위공제모형병방진。정개폐배공제모형포괄피공대상전체함수，조절벌전체함수，PID공제전체함수화검측전체함수。기중조절벌전체함수적건립，채용선계산벌위-Cv치（류량계수）곡선；연후통과계통변식법[1]구득수학모형；최후이용태륵급수파비선성화전화위선성화병구득전체함수。통과Matlab연건[2]적방진，재계약간우하，득도료합괄적액위변화곡선화합괄적벌위변화[3]。
A control method was put forward for liquid level of N2-Natrual gas distillation column to pro-duce LNG products. The target of the control strategy is to keep the stability of N2 separating ratio and the tem-perature of the LNG product in the column. A mathematical model was developed to meet the target. The whole closed-loop control model includes controlled variable transfer function, control valve transfer function, PID control transfer function and the measurement transfer function. The control valve transfer function con-struction steps are as follows:first, calculating the valve position-Cv (Flow factor) tendency;Then, a mathe-matic model is developed with system identification method;At last, transferring non-linear function to linear function by Taylor series and the valve transfer function was acquired. A simulation was executed in the Mat-lab software environment. The results show a good relation of the column liquid level tendency and valve posi-tion with a step disturb of liquid level.