Q&A on Purification Technology [035]

Series heat exchanger: By increasing the heat exchange time between the media, it is possible to reduce the temperature difference after heat exchange between them. Parallel heat exchangers: increase the flow rate of the exchange medium, with low fluid flow resistance.

1. Regarding the series connection of heat exchangers, this arrangement is generally used in situations where there are hot and cold fluid streams with temperature intersections, the heat load is high, and it is necessary to recover heat effectively. As required by the \"Process Calculation Manual for Heat Exchanger Equipment\" (see pages 5 and 12 of the manual), series connection is primarily used to address the issue of an excessively low temperature difference correction factor Ft (which is generally required to be >0.8). 2. Regarding the parallel connection of heat exchangers: ① When the heat exchangers become blocked due to factors such as scaling or coking of the fluid, it is possible to switch them without shutting down the system in order to carry out cleaning. ②If too many are connected in series, it will lead to increased resistance; yet a single heat exchanger is not sufficient to meet the requirements. ③When a single heat exchanger unit is too large, posing difficulties in design and manufacturing.

Series heat exchangers? Increase the heat exchange time between the media? This can reduce the temperature difference after heat exchange between the media. Parallel heat exchangers? Increase the flow rate of the heat exchange medium? Low fluid flow resistance.

Generally speaking, whether to use a series or parallel arrangement depends entirely on the process requirements. The advantage of series heat exchangers is their excellent heat exchange performance and thorough heat removal, but the downside is high pressure drop and limited flow rate. Parallel heat exchangers are the opposite of series ones: their heat exchange efficiency is slightly lower, but they allow for higher flow rates with lower pressure drops. Additionally, when designing systems in series or parallel, it is also necessary to take into account any limitations imposed by the available space or platform

Series heat exchanger； Increasing the heat exchange time between the exchange media can reduce the temperature difference after heat exchange between them. Parallel heat exchangers: increase the flow rate of the heat exchange medium, with low fluid flow resistance

Series heat exchangers increase the heat exchange time, while parallel heat exchangers increase the flow rate of the exchange medium

Series connection is used to improve heat exchange efficiency; when a single heat exchanger is not capable of achieving the required heat exchange capacity, we can install heat exchangers in series. Parallel connection means that multiple heat exchangers carry out the same task simultaneously, or it is also possible for just one or a few heat exchangers to be in use while the others remain as backups. This setup allows us to handle emergency situations easily by using switches and valves

The advantages of series connection are: it can prevent bypass flow, has a high flow rate, a large heat transfer coefficient, and can improve the efficiency of the heat exchanger； The disadvantages are: low processing capacity and high pressure drop. The advantages of parallel connection are: high processing capacity and low voltage drop ； The disadvantages are: it is prone to flow deviation, has a low flow rate, a small heat transfer coefficient, which reduces the heat exchange efficiency.

Answer: Series heat exchanger: By increasing the heat exchange time between the media, the temperature difference after heat exchange between them can be reduced. Parallel heat exchangers: increase the flow rate of the exchange medium, with low fluid flow resistance.

Series heat exchangers: Increase the heat exchange time between the media, which helps to reduce the temperature difference after heat exchange occurs. Parallel heat exchangers: Increase the flow rate of the exchange media, resulting in less fluid flow resistance