What is the control for the feed temperature of the analysis system?

The feed temperature of our digestion system is generally between 110 and 116°C. This temperature is primarily related to factors such as the heat exchange area of the desorption heat exchanger, the level of desorption load, and the liquid output from the second desorption tower; it cannot be controlled manually (unless there is a bypass for the desorption heat exchanger). From the perspective of steam conservation, it is better to keep this temperature at a higher level; this indicates good desorption heat exchange efficiency, ensures effective desorption of the liquid obtained in the first desorption step, and helps to reduce the consumption of low-pressure steam. Theoretically, to ensure good heat exchange performance, a higher pressure leads to better heat exchange, and the feed temperature may need to be higher as well.

While ensuring the discharge parameters of the desorption tower, keeping the inlet liquid temperature at a lower level can reduce the water content in the gas stream exiting the desorption tower. The first desorption tower is used for the rough stripping process. The amount of low-pressure steam required depends on the second desorption tower; reducing the ammonia concentration from around 1% to below 5 ppm is related not only to the amount of steam used but also to the number of trays in the second desorption tower. Based on calculations and actual production experience, the impact of the number of trays is greater than that of the steam consumption. When the feed temperature is high, sufficient steam must be added to ensure that the ammonia levels in the effluent from the desorption tower remain within acceptable limits.

I wonder what the feed temperature of everyone’s digestion system is? ? Around 110°C. How is this temperature controlled in daily production? What is the relationship between the feed temperature and the temperature of the gas released during purification? ? Proportional relationship: What is the relationship between the feed temperature and the resolution pressure? ? There is no direct relationship; the desorption pressure is related to the feed concentration. Theoretically, the feed temperature should be the bubble point temperature of the material, and that is also how the desorption tower is designed. However, in actual production, the composition of the ammonia tank cannot remain constant, so it is difficult to achieve this. Moreover, as mentioned on the second floor, many units lack direct control mechanisms for the desorption feed temperature. Its temperature control is limited; if there is a controllable heat exchanger, it is generally better to set it at a higher level, as this can help save steam. But it can’t be too high either; first, it can induce flooding ； II. Heat balance. This post was last edited by Fan Zhou Wu Hu on 2009-3-13 06:02.]

Under normal circumstances, it is better to keep the feed temperature of the distillation system at a higher level, as this helps save steam; however, it should not exceed the outlet gas temperature of the distillation tower, as otherwise flash vaporization may occur. In daily production, the feed temperature we measure ranges from 112 to 116 degrees; sometimes it can reach 118 degrees. However, our exhaust gas temperature is between 110 and 114 degrees. The control valves in the central control system are not able to regulate this temperature, but there is a bypass line on site that can be used to control it. What is the relationship between the feed temperature and the desorption gas temperature? ? If the feed temperature is high, could it lead to an increase in the moisture content of the desorption gas, and thus an increase in steam consumption? What is the relationship between the feed temperature and the resolution pressure? ? Due to high stripping pressure and an increased boiling point, the temperature of the liquid flowing into the heat exchanger during stripping rises; through heat exchange, the temperature of the feed material also increases. There are some inaccuracies in the analysis; I hope the fellow maritime enthusiasts will not hesitate to offer their guidance! ! !

Generally, the ammonia content in the water leaving the hydrolysis tower (and entering the second desorption tower) is around 1%. Since the number of trays in the second desorption tower is fixed, in order to ensure that the ammonia level in the purified water exiting this tower is less than 5 ppm, it is necessary to introduce an adequate amount of low-pressure steam; this amount is fixed； The ammonia content in the effluent from the first desorption tower is below 0.8%, which allows the hydrolysis tower to operate properly; under normal conditions of temperature, pressure, and high-pressure steam in the hydrolysis tower, the ammonia content in the effluent from the desorption tower remains below 5 ppm ； To ensure the above parameters, the feed temperature of the first desorption tower must not be too low (it is difficult to maintain a level of 0.8%) nor too high (given the fixed area of the heat exchanger, the temperature of the feed to the desorption tower cannot be too high due to limitations imposed by the heat transfer temperature difference). Therefore, the feed temperature is adjusted according to changes in the production load and the composition of the feed, in order to control the water content in the gas exiting the desorption tower. There is definitely flashing in the feed to the desorption tower; higher temperatures result in more flashing, but this does not increase gas consumption. However, the temperature of the gas exiting the tower rises, and it contains more water. The auxiliary lines of the heat exchanger in the desorption tower provide additional means for regulation.

The feed temperature in the stripping system is closely related to the concentration of the stripping liquid. When the concentration of the stripping liquid is within the designed range, the feed temperature is generally around 110°C. If the concentration is too high, the temperature needs to be kept below 100°C; otherwise, flashing of the feed will occur, leading to unstable pressure at the top of the tower and excessive moisture content. The feed temperature is directly proportional to the temperature of the gas released during stripping, but it has no proportional relationship with pressure. In a properly designed system, bypass lines are used in the stripping heat exchanger to control the temperature of the material entering the tower.

The higher the feed temperature, the greater the amount of flashing; a properly designed feed plate in the desorption tower prevents pressure fluctuations.