Whether the selection of a steam trap affects the temperature of the reactor jacket
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Previously, the enamel reaction kettles used in the company were heated by jacketed steam; the steam pressure was generally 0.4–0.6 MPa, and it was saturated steam, with a temperature of around 140–180 degrees. A drain pipe connected to the jacket has a steam trap installed on it. The problem is that it’s not clear whether the steam trap was selected incorrectly or what the cause is; in any case, steam emission is very severe, and a large amount of steam is discharged along with the water when it’s drained. Based on this phenomenon, a drain valve with a higher port pressure was replaced. The exhaust phenomenon has decreased, but the workers report that the reaction rate of the materials inside the reactor seems to have slowed down. The temperature is still high, but the reaction speed has indeed reduced. Their analysis is that this steam has poor flowability, so it’s not as good as before, because steam was constantly being released in the past. I wonder if this is the reason?
Was a thermostatic safety valve chosen, which means exhaust can only occur once the water temperature drops? Others, such as those of the thermodynamic and buoyancy types, are not needed.
You mentioned that the operating condition described should involve the direct discharge of condensate, with leakage from steam traps being ruled out. In that case, a large amount of steam is also discharged along with the water, and this steam is likely flash vapor. Mechanical steam traps (inverted drum type and float type) remove condensate based on the density difference between condensate and steam. The temperature of the condensed water discharged is, in principle, that of saturated water; at 0.4 MPa, the temperature of saturated water is 151°C, and direct discharge would result in a large amount of flash vapor. It is recommended that you use an inverted barrel-type steam trap. This type of steam trap performs intermittent drainage; it is possible to determine its operating status visually during drainage, and it allows for the timely removal of condensed water from the reaction vessel, thereby increasing the rate at which the material in the vessel heats up. If there are any doubts, we can discuss them in detail.
The last edit to this post was made by Rely on yourself in everything_LWTF on 2019-7-17 at 08:45. No matter what type of steam trap the original poster uses, the primary principle should be to ensure that normal and safe production is not affected; energy savings and consumption reduction should only be considered afterward. Due to their structural characteristics, conventional steam traps inevitably result in some fresh steam being discharged during the drainage process. According to domestic industry standards, the acceptable leakage rate for such steam traps is ≤3%. Moreover, since what is discharged is saturated condensate, the pressure differences before and after the steam trap cause this condensate to boil rapidly, generating a large amount of flash steam; this is why you see a large volume of steam being discharged. After replacing the pressure-sensitive drain valve, its backpressure increased, which may have resulted in water accumulating inside the reaction vessel. Water has a lower heat exchange efficiency compared to saturated steam; this is why the temperature of the reaction vessel remains the same yet the reaction progress is slower. At the same pressure, the temperature of water and steam is identical; at a pressure of 0.4–0.6 Mpa, both water and steam have temperatures ranging from 152–165°C. It is a great waste to let the condensed water be discharged directly through a drain valve, as the temperature of water at atmospheric pressure is only 100°C. That temperature range of 52–65°C is wasted as steam. We possess proprietary technology that allows us to recover this heat and return it to the reactor for further heat exchange, thereby reducing the amount of fresh steam required by the enterprise. Reduce corporate production costs. If the company still has boilers. The condensate can be completely recycled back to the boiler in a sealed system; the temperature of the water returning to the boiler can exceed 130 degrees, and this also helps to **reduce the fuel consumption of the enterprise’s boilers. It also eliminates the costs associated with boiler water softening and deoxygenation. The overall energy-saving effects can help businesses save 15%-25% in costs. The value is quite substantial; if you’re interested in steam energy savings, we can discuss it in more detail.
We also haven’t drained the condensate water; instead, it is reused as natural water, for things like cleaning purposes. Also, the heat exchange efficiency of water is lower than that of steam, but both fluids are located in the jacket; we measure the temperature inside the reactor vessel, not the temperature in the jacket.
As the condensate turns into natural water, the recovery temperature drops significantly; the substantial heat loss constitutes an energy waste. The temperature of the material inside the reaction vessel should be measured. It is important to determine where the temperature sensor is located, as this affects whether there will be uneven heating in certain areas. If the reaction vessel is vertical, the temperature sensor can only measure the temperature at one specific point, and thus cannot reflect the average temperature throughout the vessel. This may result in the displayed local temperature remaining the same as before, even though the average temperature of the entire reaction vessel is lower than before. The bypass valve of the hydrophobic valve can be slightly opened to check whether a large amount of condensate is discharged; if so, it can be determined whether there is water trapped inside the reactor
Steam condensate is recovered as cleaning water, but this does not constitute meaningful recovery of the condensate. There are two aspects to the value of condensate: one is its sensible heat, and the other is its quality as cleaning water. Apart from containing some iron ions that need to be removed by adding ammonia later, the ion content meets the standards required for boiler make-up water, so no further desalination or deoxygenation is necessary. According to your previous description, the condensate should be discharged directly after passing through the jacket; therefore, what is observed is likely flash steam. At sea level, temperatures above 100 degrees Celsius cause the flash steam to carry away moisture. There is a way to distinguish between flash steam and fresh steam: flash steam appears as white mist, while fresh steam is blue in color.
Firstly, a large amount of steam is released during drainage. Assuming no leaks, there are two possibilities: one is flash vapor – in systems such as inverted bucket and float-type systems, what is discharged is saturated condensate, and vaporization occurs at low pressure; the other possibility is that a thermodynamic type of system is used, in which it is normal for steam to be released during drainage. After replacing the steam trap, the temperature decreased and the reaction rate slowed down; it is likely that condensate water remained trapped, affecting the efficiency of heat exchange by the steam. It is possible that a thermostatic steam trap was used, which prevented the condensate water from being drained in a timely manner. It would be best to provide the exact type of drain valve used in both instances in order to give a clear answer.
Most strainers will allow air to escape, and at this pressure there is also vapor formation; if there is more gas than water, that is a problem
Incorrect selection of a steam trap can cause water to accumulate in the heating jacket. If water remains in the jacket, it will reduce the heating area. In the jacket, the upper layer is steam and the lower layer is water. In this case, if your temperature probe is located relatively high on the device, uneven heating will occur due to water accumulation in the jacket. So the temperature has been reached. But the heat exchange area has decreased. The reaction speed slows down.
Steam energy savings? We have centralized gas supply in the industrial park – can this save energy?