Safe Operating Envelope

Equipment used in different processes during its lifecycle. Surplus equipment or existing equipment reused for different use. Possibility of equipment being used outside its safe operating envelope. 

Available equip- Procure equipment that can be used in other ment determines processes (current or future) without operating the process chem- close to its operating envelope, istry selected., Provide equipment with comparable pressure Operating close to rating for the entire system the safe operating envelope of the batch sizes to equipment capabilities equipment and the relief capability. ... 

High temperature material fed to vessel. Temperature excursion outside the safe operating envelope resulting in a runaway reaction. 

For small vessels and slow reactions, corrections must be made because of the heat content of the reaction vessel itself. For large-scale reaction vessels and for rapid reactions, the system will be close to adiabatic operations. This aspect must be taken into account in scale-up. In effect, the extrapolation of data obtained in small-scale equipment has limitations as discussed in [193]. In case of a runaway, the maximum temperature in the reaction system is obtained from the adiabatic temperature rise, that is, Tmax = (Tr + ATad). In reality, the adiabatic temperature rise is significantly underestimated if other exothermic reaction mechanisms occur between Tr and (Tr + ATad). Therefore, a determination must be made to see if other exothermic events, which may introduce additional hazards during a runaway, occur in the higher temperature range. This can determine if a "safe operating envelope" exists. 

Therefore, the data that can be obtained from these tests, which will help in specifying the safe operating envelope on the full-scale plant, include ... 

Preventive measures either take automatic remedial action or allow for manual intervention to prevent the conditions for uncontrolled reaction being achieved. They include the use of sensors, trips, alarms, control systems, and other safety features. These measures require a.thorough understanding of the safe operating envelope within which the process must be maintained.. . ... 

At PPG, Class 1 Prooftesting also covers 250 Safety Instrumented System loops in the PSM Safety Systems. A Safety Instrumented System (SIS) is composed of sensors, logic solvers, and final control elements for the purpose of taking the process to a safe state when predetermined conditions are violated. SISs are normally controlled by a PLC with the sole function of monitoring a process to insure operation is maintained within the safe operating envelope. 

Raising a reactor operating temperature within the safe operating envelope. 

Proposals to operate at significantly different pressures, temperatures, flow rates, acidity, etc., which are considered outside the well-understood and documented Safe Operating Envelope. ... 

The Safe Operating Envelope has been defined as the range of process parameters (such as temperature, pressure, flow, level, composition) that are critical to safe operation. The Safe Operating Envelope upper/lower limits are listed in the Safe Operating Envelope tables maintained under Process Safety Information. Operating beyond these limits will cause a process upset. Key maximum and minimum Emits are set based on manufacturers specifications, theoretical calculations, or operating experience. 

Does the change involve revisions to critical operating procedures that could result in operating outside of the defined safe operating envelope ... 

Raising the maximum storage tank level within the safe operating envelope for that tank. Replacement of a vessel or piping with equipment of the same size, metallurgy, wall thickness, pressure rating, and design temperature. 

The goal for passive load flow design is to use the intermediate loop flow and temperature information and only this information to cause the reactor to self adjust its power level such as to exactly match that heat demand communicated through the flibe loop - and to do so within a safe operating envelope. 

Figure 3.20 Safe operating regimes for three combustion concepts (CST in Fig. 3.3, i-CST in Fig. 3.16B, and fuel-rich in Fig. 3.16A) as a function of total equivalence ratio ( ot) and mixture preheat (T,n) for (/,n = 10 m/s. Areas below the lines define safe operating envelopes for each concept. Adapted from Schultze and Mantzaras (2013) (with permission).

Lifecycle Safety Report Fault Schedule Cat/Class Report Safe Operating Envelope Safe and Simple (Genesis) Report Internal Hazards External Hazards Human Factors Electrical Power... 

The WEC UKP-GW-GL-736, Safe Operating Envelope and Operating Regime that Maintains Integrity of Envelope (Reference 1.8) describes the principles behind development of the safe operating envelope and how this information has been used to support the design basis assessment and plant technical specifications. 

WEC, UKP-GW-GL-736 Rev 0, Safe Operating Envelope and Operating Regime that Maintains Integrity of Envelope, November 2008. 

The safe operating envelope of the APIOOO is defined by the operational parameters within which it can be safely operated, and by the protective safety measures that must be available in case a duty system fails. The limiting operational parameters are the boundary conditions assumed by the transient analysis for each fault in the design basis fault schedule (see Section 5.2 of this PC SR). The conditions placed on the availability of protective safety measures are based on the required reliability of providing the nuclear safety function, given the postulated frequency and consequences of each fault. 

The safe operation of a reactor requires that the controls keep the system operating within a safe operating envelope (see also Chapter 21). The envelope is based on many of the design and process constraints. These are placed on the unit to ensure the proper operation. Additional controls may be installed to operate additional equipment needed for energy recovery, neutralization, etc. 

Most industrial process plants are safe to be around. Plant management, aided by reliable operators, who are in turn backed up by still-more-reliable automatic controls, does its best to keep operations moving along within the limits usually considered reasonably safe to man and machine in order to have a safe operating envelope. Occasionally, however, there is a whoosh or a bang that is invariably to the detriment of the operation, endangering investment and human life, and radely upsetting the plant s loss expectancy. 

The licensing process should generally include a consideration of the OLCs in the form of controls, limits, conditions, rules and required actions that are formally derived from the safe operating envelope. The safe operating envelope is encompassed by the possible operating states included in the... 

---