Selection of ammonia preheating temperature
Thread Content
In the aqueous solution full-cycle method, the ammonia preheating temperature is used to maintain thermal equilibrium in the synthesis tower. Many sources state that for every 20-degree increase in the ammonia preheating temperature, the temperature of the synthesis tower rises by only 1 degree. However, this is not the case in actual production; a slight increase in the ammonia preheating temperature results in a significant rise in the temperature of the synthesis tower. What temperature do you usually set for ammonia preheating? Is it effective to control the synthesis tower temperature by using a higher ammonia preheating temperature and a higher ammonia-to-carbon ratio?
1. In the aqueous solution full-cycle process, under normal operating conditions, changes in the ammonia preheating temperature have little effect on the temperature of the synthesis tower, provided that the ammonia-to-carbon ratio, water-to-carbon ratio, and production load remain constant. II. Under normal production conditions, the temperature of liquid ammonia at the outlet of the liquid ammonia preheater is 55–60 oC. III. The main factors affecting the temperature of the synthesis tower are the ammonia-to-carbon ratio and the water-to-carbon ratio; therefore, fluctuations in the synthesis tower’s temperature are primarily caused by changes in the composition of the materials fed into the tower. By controlling the ammonia-to-carbon ratio and the water-to-carbon ratio, it is possible to control the temperature of the synthesis tower. IV. Reasons affecting temperature changes in the synthesis tower: 1. When the ammonia-to-carbon ratio remains constant and the water-to-carbon ratio increases, the temperature at the bottom of the tower rises while the temperature at the top of the tower drops ； 2. With the ammonia-to-carbon ratio remaining constant, a decrease in the water-to-carbon ratio leads to a drop in the bottom temperature of the tower and an increase in the top temperature ； 3. With the ammonia preheating temperature remaining constant, a decrease in the ammonia-to-carbon ratio leads to an increase in both the bottom and top temperatures of the tower; however, when the ammonia-to-carbon ratio is less than 2, the bottom temperature decreases ； 4. With the ammonia preheating temperature unchanged, an increase in the ammonia-to-carbon ratio leads to a decrease in the bottom temperature of the tower as well as a decrease in the top temperature of the tower ； 5. An increase or decrease in the ammonia preheating temperature results in little change in the temperatures at the top and bottom of the tower ； 6. With the production load remaining unchanged, the temperature of carbon dioxide gas decreases, and both the top and bottom temperatures of the tower drop ； 7. With the production load remaining unchanged, the purity of carbon dioxide gas decreases, and the temperatures at the top and bottom of the tower drop.
When the preheating temperature of ammonia increases or decreases, significant changes occur in the temperatures at the top and bottom of the tower. It is possible to determine how many cubic meters of ammonia are required per ton of urea; if the temperature of this ammonia rises by a few degrees, it is possible to calculate the amount of heat load involved. Go ahead and do the calculations...
The specific heat of ammonia seems to be the highest among liquids, higher than that of water. Whether ammonia is preheated depends on the process, but it is preheated in most cases.
Why is it necessary to send a stream of dimethyl ether from the outlet of the dimethyl ether distillation tower to the dimethyl ether product separator? Effect?
How is the stress effect defined? Thank you. Quickly
What are the physical and chemical properties of dimethyl methoxide? And the operation manual?
During normal operation, the temperature of the liquid ammonia preheater is generally maintained between 40 and 70 degrees; as long as it remains within this range, no further adjustments are necessary. Nor can this temperature be used to adjust the temperature of the synthesis tower.
The original Cabon process did not include ammonia preheating; it was merely a measure for heat recovery aimed at reducing steam consumption, and its effectiveness was actually limited. Those manufacturers that had preheating were redesigned later. It is mainly for energy-saving reasons.