Calculations regarding heat exchangers
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I would appreciate your guidance. When cooling a medium with low flow rates, such as 3–4 m3/H, resulting in a temperature drop of 30–40 degrees, what factors should be taken into account when calculating the requirements for a cooler?
““What issues to pay attention to” is a question that is difficult to answer, or even impossible to answer. Usually, after discussing the issue in detail and providing a comprehensive overview of it, emphasis is placed on the areas where problems might arise. You haven’t said anything here; how can one determine where problems might occur? I said you need to be careful to save the document every half hour while doing calculations, so as to avoid losing the file in case of a power outage or system crash; this is also part of the precautions
It is recommended to ask more detailed questions when initiating a project. Basically, one needs to know the type of fluid, its state (liquid/gas), its physical properties (such as specific heat), the desired temperature difference, the available space for installing the equipment, cost considerations, the flow rate, and the type of heat exchanger desired, etc. Only in this way can a more effective discussion take place
There are many free calculation software programs available for download online; manual calculations are too time-consuming, such as HTFS, HTRI, etc.
Thank you all for your advice. The question is as follows: 10% sulfuric acid needs to be cooled from 58 degrees to 40 degrees, with a flow rate of 4 m3/h. The cooling water enters at 32 degrees and exits at 42 degrees. A shell-and-tube graphite cooler with an outer diameter of around 450 mm is intended to be used; the heat exchange area required is to be determined. (Outer tube diameter 32, inner diameter 22, center distance 39, baffle height 3/4 of diameter, spacing less than 400)
10% sulfuric acid is cooled from 58 degrees to 40 degrees; the flow rate is 4 (m3/h) = 4280 (kg/h), with a specific heat of 3855 (J/KG·°C). Thus, Q = 296989200 (J/h). The cooling water is heated from 32 degrees to 42 degrees, with a specific heat of 4178 (J/KG·°C); therefore, 7108 (KG/h) of water is required. The LMTD is 11.54 (for counterflow). The heat exchanger uses graphite combined with tube design (for cooling purposes). The heat transfer coefficient ranges from 581.5 to 930.4 (W/M2·°C); an average value of 760 (W/M2·°C) is used. Q = UA·LMTD, so A = 9.4 M2. There may be software or programs that can conduct more accurate calculations, but... based on purely manual calculations, I believe the area obtained will be fairly close to that calculated using software.