化工学报
化工學報
화공학보
JOURNAL OF CHEMICAL INDUSY AND ENGINEERING (CHINA)
2010年
4期
893-900
,共8页
费正顺%胡斌%叶鲁彬%郑平友%梁军
費正順%鬍斌%葉魯彬%鄭平友%樑軍
비정순%호빈%협로빈%정평우%량군
聚合反应%牌号切换%控制变量参数化%路径约束
聚閤反應%牌號切換%控製變量參數化%路徑約束
취합반응%패호절환%공제변량삼수화%로경약속
polymerization%grade transition%control vector parameterization%path constraints
产品多样化需求使得聚烯烃生产过程中经常需要进行牌号切换操作.以往关于牌号切换优化的研究大多只关心切换过程结束后聚合物质量指标是否达到目标牌号值,对过渡过程中质量指标及状态变量的波动情况缺少关注,而过程的波动会影响到最终产物的质量性质和操作平稳性.为此,本文以聚乙烯气相流化床反应器为对象,通过在牌号切换优化命题中加入关于熔融指数等的路径约束,防止过渡过程中的状态变量剧烈波动影响聚合物树脂质量.为求解此类带路径约束的动态优化问题,对常规的控制变量参数化方法进行了改进,通过求解微分代数方程(DAE方程)将路径约束转化为控制变量约束.仿真结果表明,加入路径约束可以有效避免牌号切换中变量的剧烈波动,增强过程平稳性.
產品多樣化需求使得聚烯烴生產過程中經常需要進行牌號切換操作.以往關于牌號切換優化的研究大多隻關心切換過程結束後聚閤物質量指標是否達到目標牌號值,對過渡過程中質量指標及狀態變量的波動情況缺少關註,而過程的波動會影響到最終產物的質量性質和操作平穩性.為此,本文以聚乙烯氣相流化床反應器為對象,通過在牌號切換優化命題中加入關于鎔融指數等的路徑約束,防止過渡過程中的狀態變量劇烈波動影響聚閤物樹脂質量.為求解此類帶路徑約束的動態優化問題,對常規的控製變量參數化方法進行瞭改進,通過求解微分代數方程(DAE方程)將路徑約束轉化為控製變量約束.倣真結果錶明,加入路徑約束可以有效避免牌號切換中變量的劇烈波動,增彊過程平穩性.
산품다양화수구사득취희경생산과정중경상수요진행패호절환조작.이왕관우패호절환우화적연구대다지관심절환과정결속후취합물질량지표시부체도목표패호치,대과도과정중질량지표급상태변량적파동정황결소관주,이과정적파동회영향도최종산물적질량성질화조작평은성.위차,본문이취을희기상류화상반응기위대상,통과재패호절환우화명제중가입관우용융지수등적로경약속,방지과도과정중적상태변량극렬파동영향취합물수지질량.위구해차류대로경약속적동태우화문제,대상규적공제변량삼수화방법진행료개진,통과구해미분대수방정(DAE방정)장로경약속전화위공제변량약속.방진결과표명,가입로경약속가이유효피면패호절환중변량적극렬파동,증강과정평은성.
To meet a demand for various polymer products,grade transitions are frequently required in the polymerization process.The recent studies for grade transition optimization mostly focused on adjusting the quality specifications to target values.However,the variations on quality specifications and state variables during the grade transition will greatly affect the operation stability of the system and the product qualities.In this study,the authors proposed a simple and effective approach to alleviate the fluctuations during grade transition by adding path constraints to the optimization structure of grade transition in a gas-phase fluidized bed reactor for polyethylene.The path constraints were transformed to control variable constraints by solving the differential algebraic equation,which significantly improves the traditional control vector parameterization method to solve dynamic optimization problems with path constraints.The simulation results confirm the effectiveness of the proposed approach to enhance the operation stability.