Operating Procedures shut down

Another serious problem in heat exchangers is corrosion. Severe corrosion can and does occur in tubing and very often with common fluids such as water. Proper material selection based on a full analysis of the operating fluids, velocities and temperatures is mandatory. Very often, heavier gauge tubing is specified to offset the effects of corrosion, but this is only a partial solution. This should be followed by proper start-up, operating and shut-down procedures. 

Installation Site planning environment, process connections, start-up procedures, shut-down procedures, application modifications, implementation of functions in systems already operating. 

If immediate operating response is not sufficient, the operator can shut down sections of the unit so that the affected equipment can be repaired. Procedures to do with emergency operations and shutdown tell the operator how to do this without causing any further damage and without jeopardizing other units. Once more, the facility remains in operation. 

Procedures to be followed by employees who remain to operate or shut down operations before they evacuate... 

Wlien the process is shut down to make a change, then the operating procedures must be updated before restarting the process. 

All processes may be classified as batch, continuous, or semibatch depending on how materials are transferred into and out of the system. Also, the process operation may be characterized as unsteady state (i.e., transient) or steady state, depending on whether the process variables (e.g., pressure, temperature, compositions, flowrate, etc.) are changing with time or not, respectively. In a batch process, the entire feed material (i.e., charge) is added instantaneously to the system marking the beginning of the process, and all the contents of the system including the products are removed at a later time, at the end of the process. In a continuous process, the materials enter and leave the system as continuous streams, but not necessarily at the same rate. In a semibalch process, the feed may be added at once but the products removed continuously, or vice versa. It is evident that batch and semibatch processes are inherently unsteady state, whereas continuous processes may be operated in a steady or unsteady-state mode. Start-up and shut-down procedures of a steady continuous production process are examples of transient operation. 

All gas-fired plant should be provided with operating instmctions for shutting down as well as starting up. Such instmctions will ensure that the correct sequence of operations is carried out to both avoid a hazard during the shutdown and to leave the plant in a safe condition. These procedures should also contain instmctions for actions to be carried out in emergencies. Such actions may differ from the normal shutdown. 

Consider the segment of tubular reactor shown in Figure 8.3. Since the fluid composition varies with longitudinal position, we must write our material balance for a reactant species over a different element of reactor (dVR). Moreover, since plug flow reactors are operated at steady state except during start-up and shut-down procedures, the relations of major interest are those in which the accumulation term is missing from equation 8.0.1. Thus... 

Basic engineering final flow sheets final PID data sheets for equipment, piping, process data on equipment, piping and instruments operating, start-up and shut-down procedures Dow F E Index, Mond Index, Hazop, Hazan, Fault tree, RISKAT... 

Carefully review startup and shutdown procedures and the consequence of a time delay in any step of the process. Evaluate the consequences of an extended hold or shut down period on plant operation. 

Supervision instituted new procedures. When slurry feed supply is shut down, procedures require the operators to continue agitation and acid flow for at least 30 minutes. On startup, the agitators and acid feed will be restored before starting up the slurry pumps. Both of these steps were designed to eliminate the possibility of having an undetected layer of calcium carbonate. 

To be successful providing preventive maintenance or repair maintenance, effective planning is necessary with approved procedures, proper materials, and qualified technicians. These elements are necessary when operations shuts down a single piece of equipment or shuts down an entire unit for a turn-around. Continuous good communications at the job site are imperative. 

One summer evening, the lead operator, accompanied by two operator trainees, started the No. 1 and No. 3 compressors to supply a feedstock to a unit that had been shut down during most of the day shift. The second step of the start-up procedure was to put water on the compressor water jacket. That step was inadvertently omitted in the start-up of the No. 1 compressor, and the temperature must have risen slowly. (Typically the water valves are not operated during brief shutdowns, so it may not have been checked.)... 

Operating procedures (including, start up or shut down) and maintenance schedules. 

The company policy is to regard the process operation as normal as long as the number of bad batches produced in a week is no more than three standard deviations above the mean value for the base period (i.e., as long as / I + S y)- If Y exceeds this value, the process is shut down for remedial maintenance (a long and costly procedure). Such large deviations from the mean might occur as part of the normal scatter of the process, but so infrequently that if it happens the existence of an abnormal problem in the process is considered the more likely explanation. 

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