Decoupling process units

Figure 25.1 Intermediate storage tanks decouple the processing units of a plant.

It should be mentioned that the application of this modular design is not exhaustive, it extends beyond drying and cold storage applications. The concept of a coupled and decoupled process, for easy interface between equipment and air-handling unit, can be used in many air-conditioning applications through appropriate selection of expansion valve, compressor, condensers, evaporators, and refrigerant. 

Instrumentation response times Sensor problems Time-delays Interactions between process states Interactions between process units Cascade strategies New sensors sensor location. Inferential measurement and control Predictive control. Robust controller designs Selection of control loop pairings. Decoupling control Feedforward strategies... 

In order to decouple the effects of changes in process units, adjustments are most often made to the flow of the utility streams. Utility streams are generally supplied via large pipes called headers. Changes in flowrates from these headers have little effect on the other utility flows, and hence, they can be changed independently of each other. The one notable exception to this concept is when the flowrate of a process stream is to be controlled. In this case, the process stream clearly must be controlled or regulated directly by a valve placed in the process line. 

Fig. 12 Left. ICT-PET probe 34 with a small and rigid spacer (thick black), decoupling the PET active donor = receptor unit from the 7c-conjugated ICT fluorophore. Middle and right probes 35 and 36 combining a conventional ICT and a virtually decoupled ICT process with two identical receptor units (35, for Hg2+) and two different receptor units (36, tetraoxa monoaza crown for Na+ and dithia monooxa monoaza crown for Ag+). For color code, see Fig. 10...

Thus, what is observed is a decoupling between the motions of the transition and those involved in the a transition. Indeed, in PMMA, along the high-temperature side of the j3 peak, more and more cooperativity between ester flips and chain motions is involved, in such a way that the chain motions in this temperature region could be considered as the beginning of cooperative chain motions characteristic of the a processes. The presence of rigid CMI units within the chain backbone interrupts this cooperativity and, consequently, the motions involved in the j3 transition are confined to small MMA sequences and cannot reach the extent required by the chain motions occurring at the onset of the a transition. 

Specifically, the model may be applied for the integrated energy supply and process plant for hydrogen production, or the input energy to the plant may be generalised in terms of costs for heat in USD/MWt-h and costs for electric power in USD/MWe-h. For the H2A analyses the heat and electric power were modelled as costs per unit energy inputs. Thus, the nuclear reactor economic detail is decoupled in the analysis so that the evaluation concentrates on the process plant. 

Polymerizable surfactants capable of working as transfer agents include thiosulfonates, thioalkoxylates and methyl methacrylate dimer/trimer surfactants. Thioalkoxylates with 17-90 ethylene oxide units were produced from ethoxylated 11 bromo-undecanol by replacing the bromine with a thiol group via the thiazonium salt route [8]. In the presence of water-soluble azo initiator the thio ended Transurfs (used at a concentration above the CMC) gave monodispersed latex particles in emulsion polymerization of styrene. However, the incorporation of the Transurf remained low, irrespective of the process used for the polymerization (batch, semibatch, seeded). The stability of the lattices when the surfactant and the transfer function were incorporated in the same molecule was better than when they were decoupled. 

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