Start-up operation

Almost all new systems have need of adjustment of flow balances, level switch adjustment, or injection rates. A normal system start-up operation should consist of daily monitoring until the system stabilizes at a relatively constant rate. At the end 

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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. 

Instructions for start-up, operation and shutdown as well as those regarding prevention and suppression of failures, if any,... 

FIGURE 4.5. Decision/Action Flow Diagram of a Furnace Start-Up Operation. 

This suggests that caution must be exercised when establishing a tray efficiency for any type contacting device by (1) using actual test data if available for some similar system or (2) comparing several methods of predicting efficiency, and (3) possible use of a more conservative efficiency than calculated to avoid the possibility of ending up with a complete column with too few actual trays—a disastrous situation if not discovered prior to start-up operations. 

In this section, instructions for start-up operations and descriptions of programs are given ... 

Explosions occurred more frequently during start-up operations and in new, or relatively new, boilers. Somewhat surprisingly, the frequency of incidents was also significantly higher in the larger boiler sizes. No correlation was noted between explosion frequency and operating pressure. 

H. Nakajima, T. Konomi, and T. Kitahara. Direct water balance analysis on a polymer electrolyte fuel cell (PEFC) Effects of hydrophobic treatment and microporous layer addition to the gas diffusion layer of a PEFC on its performance during a simulated start-up operation. Journal of Power Sources 171 (2007) 457-463. 

Carryover of catalyst from the reactor disengager vessel to the main fractionator is always a concern and particularly susceptible during start-up operations. The modification of the riser termination as part of a short contact time riser revamp, depicted in Figure 7.3, has increased the concern for catalyst carryover. 

Figure 5 shows the axial gas and solid temperature profiles during start-up operation. Notice that the hot spot in the reactor moves down the bed as the heat of reaction increases the temperature of the catalyst particles. Also note the significant temperature difference between the catalyst and gas in the early part of the reactor, where conversion is rapid due to the heat of reaction being generated on the catalyst surface. These differences are even more pronounced (over 20 K) near the center of the bed and near the outer wall.11... 

The aluminum industry no longer uses the natural mineral for operation of electrolytic cells except infrequently for start-up operations. The... 

The operations book, which contains detailed instructions for starting up, operating, and both routine and emergency shutdown of the process... 

In all large and complex systems developed by contract developers, it is normally the practice to perform an SAT. The SAT is the set of activities comprising the system installation, start-up, operational testing, and user orientation performed by the software supplier/integrator in the operational environment. For the purposes of this book, the operational testing performed as part of the SAT is also known as the OQ2. If the SAT is conducted according to approved protocols, test results are properly documented, and test results reviewed and approved by the user and QA, it may not be necessary to repeat the installation and operational qualifications. This provides cost savings and can streamline the validation process. Refer to Sidebar 10-2. 

The SAT is an acceptance test comprising system installation, start-up, operational testing, and handover to customer, performed by the supplier/ integrator in the operational environment. As with the FAT, the user s representative should witness the tests and evaluate the results of the SAT. 

The simulation of actual start-up operation is very difficult unless there is a detailed rigorous model including plate hydraulics. However, the simulation of start-up operation from step 5 (section 3.3.1) is fairly easy and can be done without considering a detailed hydraulic model. To do this the filling of the holdup in steps 3 and 4 (section 3.3.1) can be achieved in different ways ... 

Twelve process safety elements have been identified as important in the context of plant design, construction, start-up, operation, maintenance, modification, and decommissioning. This does not include personnel safety, transportation issues, chronic releases to the environment, or community response, which are separate and important issues. Process safety management must deal with each element. Even the best companies, with the best safety records, have room for improvement. 

The classifying crystallizer (Fig. 18-70) requires approximately the same control of the fines-removal stream and, in addition, requires control of the fluidizing flow circulated by the main pump. This flow must be adjusted to achieve the proper degree of fluidization in the suspension chamber, and this quantity of flow varies as the crystal size varies between start-up operation and normal operation. As with the draft-tube-baffle machine, a considerably higher degree of skill is required for operation of this equipment than of the forced-circulation type. 

Work instructions and SOPs dehne the operations required to start-up, operate, monitor, shutdown, and maintain systems. These work instrnctions and SOPs must be controlled in order to prevent inadvertent and unauthorized modihcation and to ensure access to only the latest revision of the document. Work instructions and SOPs mnst, therefore, be held in accessible but secure areas that are periodically backed up and archived. Information system access must be controlled by a hierarchical security system that constrains system operations in accordance with the role, responsibilities, and competency of the nser. Access to and modihcation of the information supporting snch work instructions and SOPs — for example, engineering drawings and specihcahons — must be controlled equally. 

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