降低运行成本、提质增效、节能减排是目前火电行业的迫切需求。阐述汽轮机组数字式电液控制系统(digital electric-hydraulic control system,DEH)在转速控制模式下普遍存在的启机暖机时间长、暖机不充分、汽缸温升率较难控制以及甩负...降低运行成本、提质增效、节能减排是目前火电行业的迫切需求。阐述汽轮机组数字式电液控制系统(digital electric-hydraulic control system,DEH)在转速控制模式下普遍存在的启机暖机时间长、暖机不充分、汽缸温升率较难控制以及甩负荷后操作复杂、转速难以稳定、短时间内重新并网困难等问题。从汽轮机调节汽门、控制机构入手,分析机组启动暖机的加热过程及甩负荷后的动态过程,对比现有技术的利弊,总结得出在机组启动过程中阀位函数设置不合理、甩负荷后DEH转速控制模式与旁路阀门特性不匹配是导致上述问题的根本原因。提出一种汽轮机DEH转速控制模式下的变阀位函数的优化方法,该方法能够实现自动暖机和机组甩负荷后的快速并网,在提高机组安全性的同时,保障机组的经济性,极大减轻了运行人员的工作压力及工作量。展开更多
Listening teaching is the weakest part of English teaching in vocational colleges.College students feel the sense of uncertainties derived from language,content,presentation and visual aids,resulting in anxiety and fr...Listening teaching is the weakest part of English teaching in vocational colleges.College students feel the sense of uncertainties derived from language,content,presentation and visual aids,resulting in anxiety and frustration rather than sense of fulfillment.Against the above-mentioned negative uncertainties,this article proposes four warming-up activities in pre-listening stage,aiming to stimulate the students' motivation and improving their listening competence.展开更多
文摘降低运行成本、提质增效、节能减排是目前火电行业的迫切需求。阐述汽轮机组数字式电液控制系统(digital electric-hydraulic control system,DEH)在转速控制模式下普遍存在的启机暖机时间长、暖机不充分、汽缸温升率较难控制以及甩负荷后操作复杂、转速难以稳定、短时间内重新并网困难等问题。从汽轮机调节汽门、控制机构入手,分析机组启动暖机的加热过程及甩负荷后的动态过程,对比现有技术的利弊,总结得出在机组启动过程中阀位函数设置不合理、甩负荷后DEH转速控制模式与旁路阀门特性不匹配是导致上述问题的根本原因。提出一种汽轮机DEH转速控制模式下的变阀位函数的优化方法,该方法能够实现自动暖机和机组甩负荷后的快速并网,在提高机组安全性的同时,保障机组的经济性,极大减轻了运行人员的工作压力及工作量。
文摘Listening teaching is the weakest part of English teaching in vocational colleges.College students feel the sense of uncertainties derived from language,content,presentation and visual aids,resulting in anxiety and frustration rather than sense of fulfillment.Against the above-mentioned negative uncertainties,this article proposes four warming-up activities in pre-listening stage,aiming to stimulate the students' motivation and improving their listening competence.
