Process instrumentation system

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Process instrumentation system—Senses the state of the plant, when used together with the nuclear instrumentation, in-core instrumentation, and digital rod position indication system. 

The process instrumentation system of the JRR-3M is consists of an instrumentation and control system and a safety protection system It is designed to measure process variables, such as flow rate, temperature, water level, pressure and so on, to provide information which is necessary for reactor operation and safety protection The measuring methods adopted in the system are of conventional ones but safety important components used are specified as reactor grade ... 

The reactor protection system is designed to automatically operate the control rod system and shut down the reactor in safety in the case of anticipated operational occurrences and accidents. The reactor protection system is fully covered with the safety protection system and is operated by signals from the neutron instrumentation system, the process instrumentation system and the process radioactivity monitoring system. 

Process Instrumentation and Control Systems. Investment for instmmentation and control systems and their installation typically range between 3 to 10% of the total installed cost for a grassroots continuous process faciUty. Instmmentation and control systems also represent a substantial percentage of the overall faciUty maintenance (qv) costs. Investment costs may be placed in one of two categories, ie, nondiscretionary and discretionary. 

Operation When operated correctly, thickeners require a minimum of attention and, if the feed characteristics do not change radically, can be expected to maintain design performance consistently. In this regard, it is usually desirable to monitor feed and underflow rates and sonds concentrations, flocculant dosage rate, and pulp interface level, preferably with dependable instrumentation systems. Process variations are then easily handled by changing the principal operating controls—underflow rate and floccirlant dose—to maintain stability. 

The safe operation of a chemical process requires continuous monitoring of the operation to stabilize the system, prevent deviations, and optimize system performance. This can be accomplished through the use of instrumentation/control systems, and through human intervention. The human element is discussed in Chapter 6. Proper operation requires a close interaction between the operators and the instrumentation/control system. To a large extent, batch operations have simple control systems and are frequently operated in the manual mode. The instrumentation system is the main source of information about the state of the process. Some of the typical functions of the instrumentation/control system are... 

Same sensor used for basic process control system and safety instrumented system. Failure of sensor leads to loss of control system and safety system functionality. 

ISA-S84.01-1996, Application of Safety Instrumented Systems for tbe Process Industries, Instrument Society of America, Research Triangle Park, NC. 

Part 2 Classification of Process Control Systems Realization, operation and testing of safety instrumented systems (December 1998)... 

Safety Instrumented System (SIS) The instrumentation, controls, and interlocks provided for safe operation of the process. 

Actual development of intelligent batch process control systems, for lab, pilot plant, and plant, based on better process understanding and better instruments. 

The batch process control system we ve purchased provides only a starting point for our process research lab we must also identify and test a comprehensive set of controlled devices and real-time process instruments for chemists and engineers to use as building blocks for real feedback control systems. The technologies we are evaluating for characterization of polymer batches at all process stages include ... 

This chapter will address the applications of protein-based bioinformatics to analysis of microorganisms introduced intact into the instrumental system for rapid processing and analysis. Strategies that require offline extraction and fractionation of proteins will not be discussed. Although the amplification of nucleic acids is a powerful approach, especially coupled with mass spectrometry,15 it requires extraction and processing, and thus is not included. 

The Instrumentation and Control Fundamentals Handbook was developed to assist nuclear facility operating contractors provide operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of instrumentation and control systems. The handbook includes information on temperature, pressure, flow, and level detection systems position indication systems process control systems and radiation detection principles. This information will provide personnel with an understanding of the basic operation of various types of DOE nuclear facility instrumentation and control systems. 

LOPA is a semi-quantitative tool for analyzing and assessing risk. This method includes simplified methods to characterize the consequences and estimate the frequencies. Various layers of protection are added to a process, for example, to lower the frequency of the undesired consequences. The protection layers may include inherently safer concepts the basic process control system safety instrumented functions passive devices, such as dikes or blast walls active devices, such as relief valves and human intervention. This concept of layers of protection is illustrated in Figure 11-16. The combined effects of the protection layers and the consequences are then compared against some risk tolerance criteria. 

IEC (2001), IEC 61511, Functional Safety Instrumented Systems for the Process Industry Sector, Parts 1-3. (Draft in Process), Geneva International Electrotechnical Commission. 

Where process, safety, and environmental considerations permit, vacuum protection may be provided by properly sized ever-open vents. Alternatively, active protective devices and systems are required. Vacuum breaker valves designed to open and admit air at a predetermined vacuum in the vessel are commonly used on storage tanks, but may not be suitable for some applications involving flammable liquids. Inert gas blanketing systems may be used if adequate capacity and reliability can be ensured. Where the source of the vacuum can be deenergized or isolated, suitably reliable safety instrumented systems (e.g, interlocks) can be provided. 

Include provisions for detecting abnormal process conditions and bringing the process to a safe state before an emergency situation occurs (Safety Instrumented Systems). 

References Guidelines for Safe and Reliable Instrumented Protective Systems, American Institute of Chemical Engineers, New York, 2007 ISA TR84.00.04, Guidelines for the Implementation of ANSI/ISA 84.00.01-2004 (IEC 61511), Instrumentation, Systems, and Automation Society, N.C., 2005 ANSI/ISA 84.00.01-2004, Functional Safety Safety Instrumented Systems for the Process Industry Sector, Instrumentation, Systems, and Automation Society, N.C., 2004 IEC 61511, Functional Safety Safety Instrumented Systems for the Process Industry Sector, International Electrotechnical Commission, Geneva, Switzerland, 2003. 

Safety instrumented function (SIF) A safety function allocated to the safety instrumented system with a safety integrity level necessary to achieve the desired risk reduction for an identified process hazard. 

Introduction The chemical processing industry relies on many types of instrumented systems, e.g., the basic process control systems (BPCSs) and safety instrumented system (SIS). The BPCS controls the process on a continuous basis to maintain it within prescribed control limits. Operators supervise the process and, when necessary, take action on the process through the BPCS or other independent operator interface. The SIS detects the existence of unacceptable process conditions and takes action on the process to bring it to a safe state. In the past, these systems have also been called emergency shutdown systems, safety interlock systems, and safety critical systems. 

Safe Automation and ANSI/ISA 84.01-1996 served as significant technical references for the first international standard, IEC 61511, issued by the International Electrotechnical Commission (IEC). In the United States, IEC 61511 was accepted by ISA as ISA 84.00.01-2004, replacing the 1996 standard. In 2004, the European Committee for Electrotechnical Standardization (CENELEC) and the American National Standards Institute (ANSI) recognized IEC 61511 as a consensus standard for the process industry. IEC 61511 covers the complete process safety management life cycle. With its adoption, this standard serves as the primary driving force behind the work processes followed to achieve and maintain safe operation using safety instrumented systems. 

Air intakes to heating and ventilation systems, air compressors for process, instrument and breathing air, and to prime movers for gas compressors, power generation and pumps should be located as far as practical from contamination by dust, toxic and flammable materials release sources. They should not be located in electrically classified areas. If close to possible vapor releases (as confirmed by dispersion analyses( they should be fitted with toxic or combustible gas detection devices to warn of possible air intakes hazards and snutdown and isolate the incoming air ductwork and fans. 

Suggested control and instrumentation for the management of process components are shown in API RP I4C which is still relatively the standard within the industry. All process control systems are usually reviewed by a Process Hazard Analysis, which will deem if the provided mechanism area is adequate to prevent a catastrophic incident. 

Various simple and sophisticated fire and gas detection systems are available to provide early detection and warnings of a hydrocarbon release which supplement process instrumentation and alarms. The overall objective of fire and gas detection systems are to warn of possible impending events that may be threatening to life, property of continued business operations, that are external to the process operation. 

Process controls and instrumentation only provide feedback for conditions within the process system. They do not report or control conditions outside the assumed process integrity limits. Fire and gas detection systems supplement process information systems with instrumentation that is located external to the process to warn of conditions that could be considered harmful if found outside the normal process environment. Fire and gas detection systems may be used to confirm the readings of major process releases or to report conditions that process instrumentation may not adequately report or be unable to report (i.e., minor process releases). 

Human beings provide the first line of observation and defense for any facility. Periodic or constant first hand operator on site surveillance of the process provides careful observation and reporting of all activities within the facility. Humans have keen senses that have yet to be expertly duplicated by instrumentation devices or sophisticated technical surveillance mechanisms. In this fashion they are more valuable in the observation of system performance than ordinary process control systems may be. 

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