Malfunction parameters

Volatile acids, reported as acetic acid, are the most important operational parameter. In a weU-operating digestion process, the value should be <1 g/L (3.8 g/gal). A value >6 g/L (23 g/gal) indicates malfunctioning optimum pH is 6.8—7.2, and a pH <6.8 indicates excessive volatile acid production. Formerly, lime was added to the digester contents if the pH showed an undesirable drop. However, the reduction in pH indicated a change in organism that could not be remedied with lime (2). 

If failure is initiated by an increase in internal pressure in combination with a malfunctioning of the pressure relief, the pressure at failure will equal the failure pressure of the vessel. This failure pressure is usually the maximum working pressure multiplied by a safety factor. For carbon-steel vessels, this safety factor can be taken as four. Mote precise calculations ate possible if the vessel s dimensions and material parameters ate known. 

The CRC is an important parameter for a unit operator to monitor periodically. Most FCC units check for CRC on their own, usually daily. The CRC is an indicator of regenerator performance. If the CRC shows signs of increasing, this could reveal malfunction of the regenerator s air/spent catalyst distributors. It should be noted that the MAT numbers reported on the E-cat sheet are determined after the CRC has been completely burned off. 

The parameters of this category should be recorded automatically using monitor channels of the data acquisition system (cf. Sect. 4.3). The value of the experiment is strongly resting on these data. In case of a malfunction or unavailability of the monitor channel module of the data acquisition system at least the most important parameter must be collected using paper and pencil. These parameters are the main process parameter6, the exposure times, and the readings of the ionization chambers. 

Module 6, Column Diagnosis (COLDIAG). This module uses chromatographic parameters such as efficiency, asymmetry, retention time, selectivity and operating pressure, to detect failures of the column or other chromatographic hardware. Table II lists the types of column failure which the module can currently handle. Note that the module will also correctly diagnose some problems which are NOT column malfunctions but which might be interpreted as such by a user. 

The heart of the system comprises the automatic units that carry out the basic operations. The individual steps of the operations are specified in a set of execution parameters, which are controlled and monitored by a microprocessor that also calculates the basic results. Apart from monitoring all operations for correct action, it is necessary to avoid the generation of incorrect analytical results and to signal the malfunctioning of any subsystem. The machine operation should allow the state of any procedure or module to be readily and easily visible. 

Radioactive tracers [14] are a useful tool to measure unit parameters such as residence times and distribution of the catalyst and vapors in the reactor, stripper, or regenerator. Bypassing can be detected, slip factors calculated and dilute phase residence times are examples of useful calculations that can point the way to future modifications. This technology is also useful for detecting and analyzing equipment malfunctions. Plugged distributors, erratic standpipes, and main fractionator problems such as salt deposits or flooding can be detected with tracers. 

Typical irradiation facilities consist of a process chamber containing the radiation source, some sort of conveyor systems to transport products inside and outside the shielding walls, and sophisticated control and safety systems. Irradiation facilities are built with several layers of redundant protection to detect equipment malfunctions and protect employees from accidental exposure. Technical details depend on the type of irradiation. Typical processing parameters are compared in Table 2 [7]. 

What about the question of whether a detector or counting system is working properly For example, the data in Table 18.2 do not exactly match a Poisson or normal distribution. Was the counting system malfunctioning One parameter that we can calculate that will help us answer such questions is x (chi squared). Formally,... 

When a failure or a malfunction occurs, first it needs to be detected. The detection time is influenced by the choice of appropriate alarm settings or by the use of more sophisticated alarm systems, as described in Section 10.4.6. Most important, is choosing the appropriate parameter which must be monitored to detect a malfunction. The design of alarms, interlocks, and control strategies is an important part of process design and should always follow the principles of simplicity in the concept of inherently safer processes (see Section 10.3). 

The term fault is generally defined as a departure of an observed variable or a parameter from an acceptable range [19, 48], The causes of this abnormality, such as a failed coolant pump or a failed sensor, are called basic events or root events and are often referred as malfunctions or failures. 

In case of complete malfunction of cooling and stirring systems, the temperature may exceed the solvent reflux temperature [34], Accordingly, a slow dosing of the methyl chloroformate is necessary to have control over the heat release. After having determined the reaction parameters at 1 g scale, the reaction was carried out in a microreactor with 91% yield at 7 min residence time. More than 1 kg of N-methoxycarbonyl-L-tert-leudne was prepared within 12 h. 

A HAZOP study is undertaken by the application of formal, systematic, and critical examination of the process and engineering intentions of the process design. The potential for hazards or operability problems are thus assessed, and malfunction of individual items of equipment and associated consequences for the whole system are identified. This examination of the design is structured around a specific set of parameters and guidewords, which ensures complete coverage of all major possible problems. 

We note here that for simplicity, we have implied that "best performance" means highest system loss factor. This is the case for a number of damping applications, but not for all cases. D. J. Mead (12., L2.) has noted the quantitative importance of other system parameters (stiffness and mass) in optimizing a damping treatment in cases where maximum loss factor is not the criterion of best performance (e.g., minimizing stress, acceleration, etc.). These considerations are particularly important in controlling structural fatigue and equipment malfunction. 

For diagnostic purposes, relevant parameters are collected and logged into the control system in order to determine appropriate maintenance periods and its service timing. For example, noise and vibration can serve as indicators of the status of health for a polisher. Large pressure and temperature valuations may provide alarms for malfunctions or problems within fluid lines. Such techniques have been developed and implemented in other technical fields, such as power generation machinery. The adoption of these mature technologies significantly improves the uptime of CMP system. 

Because the stability chambers are an integral part of the stability program and require continuous performance to specifications for long-term studies, all aspects of the chambers must be described in detail in an SOP. The SOP should include the procedures and the schedule for calibration of the chambers, the description and operating parameters, a routine maintenance schedule, inventory system, IQ/OQ procedures and a monitoring system (PQ), and emergency procedures for malfunctions or unusual occurrences. 

Reproducibility It is always necessary to confirm that the (m, T t) data measured is characteristic of the reaction of interest only and that any conclusions reached from these are based on reliable, reproducible observations. Comparisons between successive, nominally identical, experiments (and for different prepared samples of the reactant) enable the accuracy of the methods used to be assessed and meaningful error limits to be attached to reported parameters, e.g., activation energy (Ea). Repeated experiments also allow the identification (and reconsideration) of the occasional inconsistent result (was it because of unrepresentative sample, malfunction of equipment, or a programming bug ). Experiments specifically performed to establish reproducibility are not mentioned in every report, but it is always possible for unanticipated errors to occur. An appropriate... 

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