Phases of the Startup

Startup actually should begin during the plant design. For simplicity, activities can be divided into pre-mechanical completion and post-mechanical completion. See Fig. 18.1. 

The Project Manager is still the lead of the integrated team during this period. All members of the startup team help in this activity under the direction of the Project Manager. 

The Project Manager maintains the lead of the team during this period. 

The lead of the integrated team passes to the Manufacturing Manager and the Startup Manager during this period. 

Depending on the complexity or hazardous nature of the process, this startup period may be subdivided. The test period may involve simulations with water or other inert materials before active chemicals are introduced. 

---

The expenses associated with each phase of the startup were estimated to develop the start-up expenses for this first of a kind project. This exercise helped greatly in developing the operating costs. 

Preparing checklists for each phase of the startup/shutdown. 

Mission Control will not be in direct control of each step of the startup sequence. Time delays in the communication path between Mission Control and the spacecraft preclude real time monitoring and control of plant functions. Also, continuous communication with the spacecraft is not assured during the deployment and startup phases (Level 2 Requirements are 92%). It is therefore assumed that the control architecture for the Reactor Module would be designed such that an entire series of steps or phase of the startup would be initiated by a command from Mission Control and controlled autonomously from the spacecraft. Mission Control would wait for satisfactory indications that the sequence steps had been completed before proceeding with the next phase of the sequence. How the steps in the following startup sequence would be accomplished within the respective spacecraft controllers (Reactor Module and PCAD) has not been determined. 

Smooth starts are possible with steam turbine installations that include an auxiliary boiler because the startup phases of the turbocompressor can be matched to different plant operating conditions. Aside from process-related timing issues, the time elapse or machinery startup duration is generally determined by the temperature gradients admissible on both steam turbine and expander. These factors are influenced by the relative expansion rates of the fixed and rotating components in these machines. 

The aeration requirements of the deep shaft (vertical shaft bioreactor using flotation technology) are provided by two, 100 hp rotary screw compressors rated at a pressure of 7 kg/m2 (100 psig). Dissolved oxygen (DO) levels of 4 mg/L are maintained in the head tank, and during the startup phase of the plant a DO meter measured a dissolved oxygen concentration of 25 mg/L at the shaft bottom. 

The person in charge of this phase of the operation is often the person designated to become the plant manager. Some companies, however, have a startup division that is placed in charge. Others contract for this function with the construction firm. In any case, the person in charge should have had prior experience with startups. 

Steady-state modeling is not sufficient if one faces various disturbances in RA operations (e.g., feed variation) or tries to optimize the startup and shutdown phases of the process. In this case, a knowledge of dynamic process behavior is necessary. Further areas where the dynamic information is crucial are the process control as well as safety issues and training. Dynamic modeling can also be considered as the next step toward the deep process analysis that follows the steady-state modeling and is based on its results. 

After the plant is constmcted, the operations phase of the project begins, which includes plant startup. Rarely does this operation proceed smoothly. Troubleshooting, process modifications, and repairs are generally required. 

After you have completed the startup disk screens, the collecting information about your computer phase of the installation is over. The next phase of the install begins immediately. 

On April 6, 1986 the startup phase of the project was completed with full commercial production being achieved. For the remainder of the year the company received a processing fee from the Crown for converting gas into gasoline. 

To make the proj)a.ga.tor run concurrently at hi st use was made of MPI and of a Task Farm model [41]. In the startup phase the Master jirocess distributes the rows of C using a cyclic policy. This implies that in the startup phase if j = i mod M (with M being the number of scheduled Workers) the vector Raiv j. C) is sent to the worker W,. At the end of the startup phase each Worker has stored the rows received from the Master in a local (unshared) secondary space storage hereafter called Dataset Wi- C). Similarly, all the elements of the matrices A and B referred by the Worker IP) arc stored in an analogous Dataset during the wavepacket initialization (immediately before the hrst step t = 0). 

The interaction of the plant with the research and development area will be most significant during the design and startup phase of the plant and each of its products. The regulatory activities that would be required for the preparation and filing of the required documentation for the FDA, in the United States, or the Health Ministry of the country where sales are planned will be the subjects of discussion in the appropriate chapter. 

Subsequent to the earthquake, the core will be cooled by the SCS. This phase of the DBE-5 event is similar to the corresponding phase of DBE-3 (following control rod insertion and SCS startup). 

After an unexpected failure in one of the BAHX during the initial phase of the plant startup due to concluded temperature excursion and the subsequent failure analysis, new trip protection has been included in the control logics. In the analysis the main probable cause that could have occurred is the sudden vaporization of filled liquid inside the BAHX, more importance was provided to avoid liquids in the exchanger inlet by modified controls. 

An alternative way to bypass calculation of the startup period is to solve for a steady-state solution first using the MRF model. The MRF model (Section 5-5.2) provides a solution for the moving impeller at a fixed orientation relative to the baffles. Tools are available in commercial codes to use the solution data from the MRF simulation and apply it to the sliding mesh simulation as an initial condition. A moderately coarse time step can be nsed initially (say, corresponding to a 10° rotation, as in the example above) and rednced at a qnicker rate than would otherwise be advisable. This approach can also be nsed if inflow and outflow boundaries are present or if a multiphase calculation is to be performed. In the case of multiphase flows, however, care must be taken to wait until the periodic steady-state condition has been reached before introducing the secondary phase. 

There is no difference between the pressurization phases of the constant pressure startup and sliding pressure startup schemes because the pressurization phase appears after the line switching to the once-through mode. It is assumed that the core inlet and outlet temperatures are kept equal to their respective values in the normal operating condition. While the reactor core power is increased, the feed-water flow rate is also increased proportionally. MCSTs are calculated for various core powers from 30 to 100% at intervals of 10%, and the calculated results are shown in Fig. 5.11. It is found that MCST satisfies the criterion of 620°C throughout the power increase phase. 

The startup curve for the sliding pressure startup scheme that is designed based on only the thermal considerations (Fig. 5.23) is redrawn taking the stability considerations into account as well. The constant pressure startup is not discussed here because the partial power operating conditions in the constant pressure startup are covered by the temperature increase phase and power increase phase of the sliding pressure startup. 

The telecom link provides a communication path for commands to activate the Reactor l C segment and centred phases of the reactor startup. Once reactor specific commands are received on the spacecraft, they are processed by the Command and Data Handling subsystem s flight computer and passed to the Reactor l C segment. 

---