Matlab Counter-Current Heat Exchangers

Matlab Counter-Current Heat Exchangers - Heat Exchanger...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Heat Exchanger Functions Examples from HDA of Toluene Simulation of counter current heat transfer in exchanges is very straightforward, but a number of special cases may require special functions to handle them. The following Matlab functions have been used for several years in CENG 403: Program Simulates Assumptions htxcc1 Counter (or co-) current heat exchanger. Constant flow*specific heat for each fluid, constant U and A. htxcc2 Constant temperature on one side of exchanger. Constant flow*specific heat for one fluid, constant U and A. htxcc3 Similar to htxcc1 , but the arguments are different. Constant flow*specific heat for each fluid, constant U and A. htx2tub Two pass counter current heat exchanger. Constant flow*specific heat for each fluid, constant U and A. The restriction to fluids with constant flow*heat capacity could be interpreted to mean that those programs cannot be used if there is a change of state of the fluid. In a strict sense that is true, but we can get reasonable approximations by ignoring that restriction in some cases. None of the programs listed in the table require compound data to be used, but we will see that in most our examples, it is convenient to load a data file so we can get reasonable heat capacity data. htxcc1 Counter (or co-) current heat exchanger. Constant flow*specific heat for each fluid, constant U and A Example 1: Heating the HDA Reactor Streams Using HTXCC1 The effluent from the reactor in HDA process needed to be cooled before it could be sent to a flash unit. It appeared as stream 1 in the section on flash units. Inlet | Outlet Stream 1 | 2 3 Total Tmp K 929.00 | 300.00 300.00 State vapor | vapor liquid Enthalpy -50020930.3 | -176426148.5 7900057.8 -168526090.7
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Compound Stream Flows toluene 28631.5 | 1039.2 27592.3 28631.5 hydrogen 795956.6 | 795431.9 524.7 795956.6 benzene 150568.2 | 16569.3 133998.8 150568.2 methane 2387533.0 | 2378826.1 8706.9 2387533.0 biphenyl 5726.3 | 0.2 5726.1 5726.3 Total 3368415.7 | 3191866.8 176548.9 3368415.7 The two heat exchanger functions htxcc1 and htxcc3 simulate the same system. It is shown below: We will reproduce the process stream shown in the table, but make a data file that includes water since that is probably what will be used to do at least part of the cooling. The "help" comments for the first heat exchanger function shows: >> help htxcc1 Htxcc1 - simple counter current heat exchanger function [Q,To0,A]=htxcc1(Ti0,TiL,ToL,Fcpi,Fcpo,U,... dTmin,nplt) Counter Current Heat Exchanger Argument List Ti0 Inlet temperature of inner fluid TiL Exit temperature of inner fluid ToL Inlet Temperature of outer fluid Fcpi Flow*heat capacity of inner fluid Fcpo Flow*heat capacity of outer fluid U Overall Heat Transfer coefficient dTmin Minimum approach temperature Return List Q Heat Transfer Rate from outer to inner fluid To0 Exit Temperature of outer fluid A Required Heat Transfer Area nplt If given is the number of points to plot Example: >> [Qx,TAout,Area]=htxcc1(60,150,160,25,35,50,10,20) We can see that if we use htxcc1 , we need to specify the inlet and exit temperatures of
Image of page 2
one fluid and the inlet temperature of the other fluid. We also need to specify the flow*heat capacity of both fluids.
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern