Issues with the cooling water in the reflux condenser
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For the carbon dioxide stripping process, the maximum capacity of our plant’s hydrolysis system is 50 cubic meters. Initially, it is suspected that there is a problem with the reflux condenser; its heat exchange area is 550 square meters, and circulating water is used for cooling in the tube side. Due to the excellent cooling effect, crystallization occurs on the shell side of the reflux condenser. An 80-bar, 5-kilogram superheated steam source was added to the inlet pipe of the circulating water, and an 80-bar stop valve bypass was installed on the return pipe of the circulating water. However, the cooling effect remains unstable. I would like to ask what cooling medium is used in your plants’ reflux condensers； The second question is: how long did it take for the hydrolyzer to reach a pressure of 34 kilograms from the time it was brought online? Is it possible to completely close the pressure valve of the hydrolyzer, and what should be the normal liquid level in the hydrolyzer?
It is recommended to use the cooling return water from a certain evaporative cooler as the cooling medium, which may improve the situation.
The cooling water for the reflux condenser in carbon dioxide stripping has its temperature regulated; it’s not just recycled water that flows in and out directly.
Hehe, the person above – we just use recycled water directly. The design team is terrible, so I wanted to ask what type of medium your factory uses. Our hydrolyzer is horizontal in design, and it’s difficult to raise the pressure to 34 kilograms per square meter. Moreover, the 38 kilograms per square meter of steam supplied to the hydrolyzer far exceeds the required amount for decomposition; for example, when 40 cubic meters of material are processed, 5500 kilograms of steam are used, which is an excess. The maximum flow measurement capacity of our equipment is only 5500 kilograms, yet the pressure in the hydrolyzer is only 25 kilograms per square meter. Additionally, the opening degree of the atmospheric pressure control valve is only 0.25%. I’m not sure what the situation is like in other factories
Forum moderator on the 2nd floor: It is not advisable to use the circulating water from evaporative coolers as cooling water, as once there is backflow or a short shutdown, the temperature of the circulating water drops, and this can cause blockages in the backflow condenser. It is recommended to use sealed circulating water instead.
I was wondering if the cooling water in your return coolers is designed as a semi-closed circulating system. Our control is at 40°, quite stable!
guotao1217 Haiyou, is the hydrolyzer used in CO2 stripping horizontal? Does the gas phase from the hydrolyzer return to the first desorption tower? If it returns to the first desorption tower, will such a large amount of steam cause flooding in the first desorption tower? Hydrolysis capacity of 40 m3; up to 38 kilograms of steam, with a maximum of 2000 kilograms used. “The pressure in the hydrolyzer is only 25 kilograms; it’s difficult to achieve the design specifications for hydrolysis-desorption. “The opening degree of the vapor pressure control valve is only 0.25%. Ask someone who specializes in automation systems about this; either the valve selected isn’t appropriate, or there is severe internal leakage in that valve. Fix it as soon as possible; given the current situation, the performance of the desorption-hydrolysis system is likely to be unsatisfactory.
Thank you for TUOHZHE’s concern. The wastewater discharge levels are still within the specified limits, at less than 5 ppm. The gas phase from the hydrolyzer flows either to the bottom of the first desorption tower or to the reflux condenser connected to the separation tower. It’s not clear whether flooding occurs or not; in any case, the liquid level in the reflux condenser’s tank often exceeds the safe limit. The outlet temperature of this tank is about 85 degrees higher. All other parameters are within acceptable ranges. Could it be that the concentration in the ammonia tank is too high? I would appreciate it if experts could analyze this issue
Dear *aohong30, we use shared circulating water; the temperature is over 30 degrees in summer and may drop to 0 degrees in winter. Therefore, we are planning technical upgrades to use soft water for cooling
If it’s 0 degrees in winter, freezing may occur and block the pipes, so be sure to take extra precautions against freezing! Does this temperature refer to the inlet temperature or the outlet temperature? It’s probably the inlet temperature, right?
Hehe, it’s the inlet temperature; the outlet temperature is around 70 degrees. We’re a newly built factory, so we haven’t encountered winter yet, so we can only reduce the flow rate of the circulating water to control it