material and energy balancing in the process industries 044482409x

[...]... of instrumenta- 2 Material and Energy Balancing in the Process Industries tion design and optimisation for balancing purposes are now available (optimum measuring placement) Retrofitting and revamping of operating plants is now important part of investment to process industries The new design of the plant relies heavily on underlying process data Material and energy balances needed for retrofitting and. .. plants' The first part of the promise is fulfilled in Appendices C and D If the reader is more deeply interested in the physics underlying the ('macroscopic') node balances, before perusing Chapters 4 and 5 he can begin with Appendix C, 6 Material and Energy Balancing in the Process Industries and with Appendix D before Chapter 6 He will then perhaps better understand the complex nature of the processes in. .. insufficient instrumentation in one part of the plant and with huge amount of redundant data in the rest All this influences the unique solvability of the system of balancing equations and makes the balancing more difficult This situation which started in early sixties brought the need for systematic methods for the second type of balancing- the balancing based on 12 Material and Energy Balancing in. .. specify independently The other problem can be the consistent set of enthalpy data in the case of energy balancing Nowadays process simulators are widely used for designing of new processes which are capable of setting up the complete material and energy balance of even very complicated processes The other area of mass and energy balancing concerns the analysis of operating processes The advent of process. .. because process streams usually don't mix with utilities Systems of balancing equations of process streams and of individual utilities are often independent and can be solved separately The classification of the stream (12) 8 Material and Energy Balancing in the Process Industries is problematic In the subsystem (4) arises the process off-gas which is further led to the subsystem (3) to be burned in a... specify the set of first guesses of unmeasured variables which are supposed to be the result of balancing In the case of single-component (linear) balancing the situation is simple The solution in this case (if exists) is unique and is obtained in the single calculation step regardless of the first guesses of unmeasured variables If the balancing model is non-linear (all balancing except the singlecomponent... systems They usually import data from the core database, make data pre-processing and the balancing calculations proper After that, balancing results are checked by the administrator of the balancing system for correctness and the results are stored in a special database Balancing data are from this moment available via the LAN to all plant personnel and also to other information systems The raw balancing. .. feed of the column preheat To analyse such system the heat or enthalpy balance must be set up, which includes the complete information about enthalpy of streams and also Chapter 2 - Balancing in process industries 11 about heat fluxes occurring among some parts of the system We can meet with this kind of balancing either when designing a new process, or during monitoring or control of the existing process. .. 3 and 7 are unmeasured and observable Streams 8 and 9 are unmeasured and unobservable The general classification of balancing variables is presented in Fig 2-8 Anyway, we can see that even in a relatively simple flowsheet with the 22 Material and Energy Balancing in the Process Industries most simple balancing model (single-component balance) the situation starts to be a little bit difficult to interpret... simple and straightforward The major problem usually is obtaining thermodynamic properties of streams in the case of energy balance A different situation can be met in balancing used in daily operation of process plants Typical applications here are Chapter 2- Balancing in process industries 23 daily mass and utilities balancing for accounting purposes monitoring of heat recovery systems monitoring of . independent and can be solved separately. The classification of the stream (12) 8 Material and Energy Balancing in the Process Industries is problematic. In the subsystem (4) arises the process. interested in the physics underlying the ('macroscopic') node balances, before perusing Chapters 4 and 5 he can begin with Appendix C, 6 Material and Energy Balancing in the Process Industries. engineers with the primary target of process control. To improve situation in this area new techniques of instrumenta- 2 Material and Energy Balancing in the Process Industries tion design and