Dynamic Characteristics of Double-Pipe Heat Exchangers

Cohen, W.; Johnson, Ernest F.

doi:10.1021/ie50558a027

Cited by 52 publications

(15 citation statements)

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“…Nevertheless, this kind of simplification allows fundamental transfer functions capturing the main system dynamics and the influence of disturbances to be found, which can be used for implementing high-performance control schemes as shown in this paper. Equations (3) and (4) yield the same results as those in [26], whereas Equation (1) is similar to that in [21]; Equation (4) shows almost a total delay between the fluid outlet temperature and its input temperature. Equations (1)-(3) predict a resonance effect when the fluid outlet temperature is related to its velocity, solar irradiation or ambient temperature.…”

Section: Solar Plant Modelmentioning

confidence: 59%

Adaptive repetitive control for resonance cancellation of a distributed solar collector field

Álvarez

Yebra

Berenguel

2008

Adaptive Control & Signal

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This paper deals with modelling and control of the outlet temperature in a distributed solar collector field. The resonance dynamics characteristics of this kind of system are similar to those of tubular heat exchangers in the closed-loop system bandwidth when fast responses are required. Simple low-order rational models are unable to capture the resonance dynamics, which can be excited by changes in both the heat transfer fluid flow and solar irradiation.This paper proposes a new model derived from a similar model for a tubular heat exchanger. This model allows the use of low-order controllers, which can be extended to an adaptive control scheme to account for varying resonance frequencies, as a new functionality achieving fast, well-damped responses.

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Section: Solar Plant Modelmentioning

confidence: 59%

Adaptive repetitive control for resonance cancellation of a distributed solar collector field

Álvarez

Yebra

Berenguel

2008

Adaptive Control & Signal

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“…For instance, frequency analysis through transfer functions were developed in [33][34][35]. But such approaches implicitly assume a linear behavior which is suitable only locally.…”

Section: The Contribution Of This Workmentioning

confidence: 99%

Reliable compartmental models for double-pipe heat exchangers: An analytical study

Zavala‐Río

Santiesteban

2007

Applied Mathematical Modelling

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In this work, the analytical properties of the heat exchanger infinite-dimensional dynamic model are discussed. More importantly, those of a 2nd-order lumped-parameter model using the logarithmic mean temperature difference (LMTD) as driving force are derived and shown to agree with those of the former. Three essential aspects are focused: existence and uniqueness of solutions, equilibrium states, and stability properties. The results developed in this work are intended to supply a solid support for the reliability on the use of the kind of simple compartmental model that is treated. This is specially addressed to works where it is not the quantitative solutions but the qualitative behavior that is important, like modelling and simulation of heat exchanger networks and complex industrial processes where heat exchangers are involved.

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“…These models, originally developed by Cohen and Johnson (1956) for the open loop heat exchanger and by Roffel and Rijnsdorp (1974) for the open loop gas fired heater, are described in detail by Silverstein (1978). Furnace and Heat Exchanger Models.…”

Section: Model Identification During Designmentioning

confidence: 99%

Effect of design on the stability and control of fixed bed catalytic reactors with heat feedback. 1. Concepts

Silverstein¹,

Shinnar²

1982

Ind. Eng. Chem. Proc. Des. Dev.

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1Frohning, C. D.; Kolbel, H.; Ralek, M.; Rottig, W.; Schnur, F.; Schulz, H. I n "Chemierohstoffe aus Kohle"; Falbe, J., Ed.; 0. Thieme Verlag: Stuttgart, Huff, G. A. Chem. Eng. Sci. 198la, 36, 790. Satterfiekl, C. N.; Huff, G. A. Ind. Eng. Chem. Process Des. Dev. to be published, 1981b. Schlesinger, M.; Benson, H.; Murphy, E.; Storch, H. H. Ind. Eng. Chem. 1954, 46, 1322. Schumpe. A.; Serpemen, Y.; Deckwer, W.-D. Ger. Chem. Eng. 1979, 2 , 234, 267. Shah, Y. T.; Deckwer, W.-D. Chapter 6 in "Scaleup in the Chemical Process Industries"; Kabel, R.; Bisio, A., Ed.; Wiley: New York, to be published, 1982. Suganuma, T.; Yamanishi, T. Kagaku Kogaku 1966, 30, 1136. Szeri, A.; Shah, Y. T.; Madgavkar, A. Chem. Eng. Sci. 1976, 31, 225. Tareeff, M. ColloidJ. USSR 1940, 6 , 545; cited in Chem. Eng. 1957, 64(3), 273. Villadsen, J. V.; Michelsen, M. L. "Solution of Differential Equation Models by Polymonlal Approximation"; Prentice-Hall: Englewood Cliffs, N.J., 1978. Zaidi, A.; Louisi, A.; Ralek, M.; Deckwer, W.-D. Ger. Chem. Eng. 1979, 2 , 94.This paper discusses the linear and nonlinear stability analysis of a fixed bed catalytic reactor with heat exchange between the feed and product streams, with special emphasis on cases which are open loop unstable. Our approach, which uses classical frequency response techniques, contains the implicit assumption that the designer should evaluate the effect of the overall design on stability. The paper shows how at this stage, with only limited information about the process, he can determine the minimum information required for this evaluation. The method outlined clearly pinpoints where the stability problems exist because the effects of each unit operation on the system stability are evaluated independently.This work reports a kinetic study on the gasiflcation of Brazilian mineral coal with steam using a thermobalance.The coal is a high ash content (>50 wt %) subbituminous, run of mine coal (Charqueadas). Isothermal runs were made at temperatures between 800 and 1000 O C and at atmospheric pressure, using -14 +20 mesh Tyler size particles. The coal was devolatilized before the gasification. Initially, the influence of the particle size of coal and the flow of steam were studied in order to determine if diffusive effects are important. For certain conditions these effects are negligible and chemical reaction is the rate controlling step. The experimental results are well descrlbed by the unreacted core model above 850 O C and by the continuous model below this temperature. The gaseous products were determined at different times and temperatures and contained essentially H, , CO, and CO, .Comparison of the present results with other data published shows that this coal is highly reactive.

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Dynamic Characteristics of Double-Pipe Heat Exchangers

Cited by 52 publications

References 0 publications

Adaptive repetitive control for resonance cancellation of a distributed solar collector field

Adaptive repetitive control for resonance cancellation of a distributed solar collector field

Reliable compartmental models for double-pipe heat exchangers: An analytical study

Effect of design on the stability and control of fixed bed catalytic reactors with heat feedback. 1. Concepts

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