Addressing the challenges of implementing safety instrumented systems in multi-product batch processes

Adapting the requirements of IEC 61511 to a batch system can be frustrating, particularly for multi-product units. While a Safety Instrumented System (SIS) for continuous operation is often a straightforward detect-decide-act loop, implementing a SIS for a batch system may involve multiple safety functions, time- or state-dependence, intricate calculations, or complex installations. Relationships between the SIS elements and the basic process control system (BPCS) must be tightly managed, providing both for the safety of the unit and its ability to operate without spurious trips or other hindrances. These issues are further complicated when multiple products requiring different functions or setpoints are produced in the same SIS-protected batch unit.This paper will discuss the challenges particular to the design, operation, and maintenance of a SIS in multi-product batch operations and present practical options for successfully resolving the concerns. A key insight into successful adaptation is treating the batch SIS as a “permission” system for the BPCS to operate. Although many items can be addressed through clever engineering practices, sustainable success relies on proactive, robust management of the safety lifecycle.     

基于图像的数字密写技术的分析与探讨

数字密写是信息隐藏技术的重要分支,基于图像的数字密写技术有着广泛的应用.本文介绍了数字密写技术的概念、原理、几种重要的基于图像的数字密写技术及其发展方向,分析和探讨了基于图像的数字密写技术.     

基本过程控制系统(BPCS)作为独立保护层的探讨

对于特定场景，识别现有的防护措施是否满足独立保护层（IPL）的要求是保护层分析技术的核心内容。基本过程控制系统（BPCS）作为一种基本保护措施，在一定的条件下可以作为一种IPL。探讨BPCS作为IPL必须满足的条件，分析同一BPCS多重功能回路作为IPL的方法、各种影响因素、限制条件、所需的专业知识和信息及注意事项。在实际运用中，必须谨慎识别同一BPCS多重功能回路作为同一场景下的多个IPL。