Will the pressure drop after 6 kilograms of steam undergo heat exchange?

Why should condensate water at different pressures be mixed together?

First question: There will definitely be pressure loss after heat exchange with 6 kilograms of steam. Second question: The condensate passes through a steam trap, and the back pressure of such a trap is generally very low; as a result, the condensate undergoes some degree of flashing and exists in a gas-liquid mixture state. The flow rate is chosen to be relatively low, so water hammer is not likely to occur. In my opinion, whether the condensate from different sources of pressurized steam can be combined depends on whether this condensate needs to be flashed into low-pressure steam for reuse. High-pressure condensate still contains some heat that can be utilized, whereas low-pressure condensate has less value in terms of reuse

This post was last edited by asolos2010 on 2018-10-25 08:07

1. The occurrence of pressure loss is due, in addition to the temperature drop caused by the heat exchanger, mainly to the pressure drop that occurs as the fluid passes through the heat exchanger. 2. The occurrence of water hammer depends on whether there is other saturated water at a lower temperature entering the same pipeline; if so, it is possible for that saturated water at a lower temperature to vaporize as it is heated by the saturated water at a higher temperature (the temperatures of the saturated water vary due to different steam pressures used in the equipment). 3. Why must saturated waters at different pressures enter the same pipeline? It is because there is a flashing tank downstream in this pipeline, in order to maximize energy utilization. 4. After reading the above explanation, you now know how to avoid water hammer... In simple terms, it involves separating saturated water with large temperature differences... This is something I’ve experienced firsthand; I always wanted to take a different approach, but my supervisor had strong objections and wanted to make changes in other ways... You can ask water removal device manufacturers for more advice – they can surely provide you with valuable insights. The above is for reference only

Let’s talk about the situations in practice: 1. There is always a pressure drop, and this drop is caused by the resistance in the equipment, pipes, control valves, etc. 2. For condensates of different pressure levels, the best approach is to feed them into the flash tank separately; otherwise, either liquid slugging will occur or it may be impossible to expel the low-pressure condensate, resulting in a reduced heat exchange efficiency.

On the PID, 6 kilograms of steam are converted into 3 kilograms of condensate after heat exchange, and this condensate then merges with the condensate from another 3 kilograms of steam. 1. Does changing S6 to C3 cause pressure loss? The loss is way too large. Was the PID drawn incorrectly again? 2. The condensates converge directly; there is no flash tank, so I’m worried about water hammer

Generally speaking, when filling in the data for pipelines, it should be S6→C6 rather than C3; it’s most likely that there’s a mistake. The so-called reboiler heating refers to the simple “phase change” of steam, and there’s no need to deliberately reduce the pressure of the condensate water by that much, unless there are multiple condensate pipelines at the outlet of the heat exchanger that all connect to a main pipeline, and this main pipeline is connected to the steam flash drum. In that case, it’s possible that C3 will be indicated in the PID settings; otherwise, for individual devices or when filling in data, it’s basically S→C with the same numerical value. As for the occurrence of water hammer, it is due to the accumulation of condensate from various heat exchangers; varying pressure levels may cause some of this condensate to be \"heated and vaporized\", thereby generating shock waves. Therefore, your concern regarding the absence of a flash tank/vaporization tank downstream is actually unrelated to this issue. The above is based on personal experience for your reference

Is there a control valve before 6 kilograms of steam enters the heat exchanger? Otherwise, the pressure drop of the heat exchanger would not be this high. If there is a control valve, the reason for the pressure drop may be related to temperature considerations. There is a problem with your wording: is the pressure after the water-repellent valve 3 kilograms, or is it the pressure at the exit of the heat exchanger that is 3 kilograms? Or does 3 kilograms refer to the backpressure for liquid condensate recovery? If the piping is not installed properly, water hammer can occur.