摘 要
全氫煤氣罩式爐是目前世界上用于不銹鋼退火的最為先進的工業爐,而溫度控制是全氫煤氣罩式爐退火的關鍵技術之一。本文以某鋼廠全氫煤氣罩式爐溫度控制系統為研究背景,在查閱了大量國內外相關文獻的基礎上,綜述了國內外全氫罩式爐及其控制的研究狀況、發展動態以及國產化的必要性。在熟悉生產工藝及流程控制的基礎上,給出了溫度控制系統整體設計方案,并著重對罩式爐退火的溫度控制算法進行了較深入的研究。根據此罩式爐設備情況,退火過程的燃燒控制使用PID調節器,采用串級比值控制調節來完成,溫度環為主環,燃氣流量為副環控制,并在副環控制中進行相關的經驗校正值系數來優化流量值的設定值。
論文還對溫度控制系統軟件部分進行模塊化設計。在全氫煤氣罩式爐溫度控制方案設計的基礎上應用SIEMENS的S7-300 PLC給出了溫度控制算法的實現方法。
經與現場工程師一起對所提出的控制方案進行論證,此研究是可行的。除增強了系統的抗干擾能力,提高了系統工作頻率等特點外,還解決了由于煤氣壓力的波動所引起的溫度波動問題,同時保證了燃燒時的最佳空/燃比,使系統的熱效比達到最佳,不僅加速了退火爐升溫過程,大大縮短了工作周期;而且降低了能源消耗,使生產成本大大下降。
關鍵詞:罩式爐;全氫;退火;溫度控制系統;PLC;
Abstract
The gas bell-type annealing furnace of the whole hydrogen is used in the most advanced industry furnace that the stainless steel annealed in the world at present, whose temperature control is one of the key technologies. The paper is based on the temperature control system of the gas bell-type annealing furnace of the whole hydrogen of a steel plant, it is generally stated that the researches domestic and overseas,the development of control at home and foreign right now as well as the necessity based on consulting a great deal of documentation.On the base of konwing well manufacture technology and controlling flow,the overall temperature control system's solving scheme is presented and temperature control algorithm is emphatically studied. According to this equipment of bell-type furnace,PID controller and cascade ratio control system is used in this annealling process to control combustion,the temperature loop is main ring and the gas flow loop is pair,and experienced corrective values are suplied on it to optimize set value of flow.
The design of modularization is done on tempreture system software parts of this paper. The temperature control algorithm is implemented by using SIEMENS S7-300, based on the overall temperature control system's solving scheme.
The given control scheme is demonstrated by engineers and it is feasible, stenghten system anti-interrupt acpability , enhause system working frequency and other features all make sense, as well as deal with the temperature fluctuation as the gas pressure changes. Guaranteed the best ratio of air and gas when combusting, accelerated the process of anneal, shorten the work cycle, reduced enegy consumation, reduced costs of production dramatically.
Key words: bell-type furnace; the whole hydrogen; anneal; temperature control system; PLC