HTRI heat exchanger design issues
Thread Content
Heat exchange between hot water and natural gas (hot water flows in the shell side, while natural gas flows in the tube side). Shell side: pressure of 62 barg; inlet temperature: 243.4°C; outlet temperature: 69.6°C. Tube side: pressure of 33.6 barg; inlet temperature: 15°C; outlet temperature: 215°C. Two heat exchangers are connected in series, of the NEN type. After the calculations, certain problems arose in the second heat exchanger – what does this mean and how can it be resolved? Everyone, please help analyze it. Inlet temperature (hot): and outlet temperature are reversed. Isothermal single-phase cases are not allowed. Inlet temperature (hot): cannot be lower than the cold outlet temperature.
You’re still working on the design, right? The temperature differences at the inlet and outlet of your process are too large; it is recommended to first match the temperatures of the two units connected in series. Perform mass and heat balance calculations in ASPEN, and then use those results to determine the property values. The error message you can see now is that your temperature has crossed limits, which is not scientific.
This post was last edited by Awui Lingshan on 2015-7-29 at 13:40. The error message states that the temperature of the heat source for your second heat exchanger is already lower than that of the cold source. It is recommended that you operate the two heat exchangers separately before connecting them together. Additionally, the temperature difference between the two streams of material is too large, which can lead to wasted heating surface area. Consider whether high-pressure steam (around 40 bar) can be used as the heat source, or whether the cold source should be preheated first; this should help reduce the cost of your equipment