Advanced operating strategies

Effective control systems and strategies are required in order to obtain acceptable operating efficiencies from RAPS systems. Good system management also improves the longevity of both battery banks and diesel generators. 

The simplest controllers used in RAPS systems are those that regulate small PV-battery-controller systems. Such units may impose only (i) a ToCV limit  

Shortcomings associated with the use of constant-current-constant-voltage strategies become obvious when the time required to charge VRLA batteries fully from a low SoC is considered — this time can exceed 24 h for new units. Obviously, most RAPS systems are unable to provide such extended charge times, especially PV-based facilities. 

In one study [30], a gel battery retained over 90% of its original capacity after performing 5500 PSoC cycles between 40 and 70% SoC, with a full recharge every 

84 PSoC cycles. The Ah throughput of the battery was equivalent to 1500 cycles at 100% DoD, which was approximately three times that predicted by the manufacturer. Also, the total overcharge delivered to the battery was below 101%, and this gave a charge efficiency of above 99%. Another investigation [29] reported data for a novel form of gel battery operated between 60 and 90% SoC. The capacity of the battery was still greater than 80% of the nominal value after 6000 cycles. 

---

A new advanced operation strategy for simulated moving-bed (SMB) chromatographic processes is illustrated in Fig. 5.14. This makes direct use of traveling wave phenomena. 

Compared with growing studies of microorganism populations, few improvements on the development and application of stmctured deterministic models for product formation have appeared. They are essential to develop more advanced operation strategies as well as to develop control and optimization algorithms. 

Host computers. These are the most powerful computers in the system, capable of performing func tions not normally available in other units. They act as the arbitrator unit to route internodal communications. An operator interface is supported and various peripheral devices are coordinated. Computationally intensive tasks, such as optimization or advanced control strategies, are processed here. 

For more advanced machining strategies the power supply should be able to operate in pulse mode. A cheap way to obtain this supply is to use a circuit similar to the Wehnelt current interrupter (Section 2.2). The utilisation of high-power pulse generators offers more flexibility. Typical values required for the pulse duration are in the millisecond range. 

The mode of operation (batch, continuous) and the use of a dedicated or a multipurpose plant is crucial for the choice of an appropriate ISPR configuration. The successful production of bulk products such as lactic acid requires an optimized dedicated system. This production plant has special equipment and advanced control strategies and is not very flexible. Generation of additional by-products has to be avoided. High added value, low volume products such as fine chemical or natural flavors are mostly produced in multipurpose plants. Investment in additional equipment or modifications of the reaction vessels is more difficult to justify, if just a few products need the application of ISPR. In this case, the less complex ISPR configurations 1 and 3 are preferred. Fiuthermore, the outlet of the production should also be easily adjustable to the market demand. 

The GT-off design performance has also been investigated by Naqvi et al [76], The use of C02-rich stream gas turbine is also included in the analysis, which accounts for 14% of the electric gross power produced. The net electric efficiency is around 52% in the case of maximum solid temperature of 1200°C (Figure 5.26), and the electric efficiency decay due to the part-load operation is lower than that in the conventional combined cycle (higher than 94% of the nominal electrical efficiency in the case of 54% of full load) if an advanced control strategy is adopted. 

The development of a dynamic model of the recovery boiler at the mill is addressed in this study. The model would allow operators to gain deeper process knowledge, in particular the effect of input variables on the flue gas temperature out of the furnace. Future studies will consider the benefits of using such detailed model for formulating/implementing advanced control strategies. 

As part of the smart enterprise division at Visy pulp and paper mill this work is related to the development of an advanced operation/control strategy for the plant recovery boiler. The development/implementation of a steady state/dynamic model was initially conducted, in this work and was reported here. Model validation, were found to be within 6% error with respect to actual plant data (for the steady-state case) and preliminary dynamic simulations show consistent trends. Work is underway to extend the capabilities of the dynamic model to two/three dimensional case for more realistic considerations as well as to incorporate the upper furnace and steam generation sections. The developed model will then be used to investigate the implementation of advanced control strategies that could achieve different operation objectives and maintain desired paper quality for the mill. 

This chapter will discuss various measurement techniques of importance to engineers and scientists designing and operating polymer reactors and associated equipment. We will then discuss basic control concepts and conclude with more advanced control strategies. We have attempted to expand and update the fine chapter from the previous edition of this book [1]. 

Motivation of the management Often managers and supervisors have a critical look towards more advanced control systems and advanced control strategies it should be clear from the operational resirlts that improvements have been achieved. But in practice this is sometimes hard to prove, since savings are usirally small, perhaps 5% in energy consumption, smoother process operation, etc. These small improvements are often hard to monitor owing to process noise and measurement inaccuracies. 

Past experience has indicated that it is not possible to tune a standard PID controller so that satisfactory control occurs over the full range of operating conditions. As a process control specialist, you have been requested to recommend an advanced control strategy that has the potential of greatly improved control. Justify your proposed method (be as specific as possible). Also cite any additional information that you will need. 

The resulting matrix F corresponds to the 4/3 power of the original matrix R. If more advanced, GGA-type functionals are used rather than the local density approximation, the procedure becomes slightly more complicated due to the more complex forms of the functionals. Here we just briefly sketch the general strategy which is centered around the observation that these functionals can usually be interpreted as a product of operators con-... 

---