Regarding the operating conditions of the catalytic absorption tower
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The operating pressure of the catalytic absorption tower in our plant is 0.98 MPa, and the absorption levels are within the specified operational parameters; however, the content of components above C3 in the dry gas is always above 4. Do any of you know the reason? Is the pressure in the absorption tower too low?
Try it according to the following plan. 1. Increase the pressure in the absorption tower to 1.1 MPa. 2. Increase the absorption and supplementation dose. 3. Reduce the top temperature. 4. Increase the amount of absorption oil in the reabsorption tower.
By reducing the content of compounds with C3 content or higher in the dry gas, it is possible to appropriately increase the operating pressure of the absorption tower and lower its top temperature. 1. Gradually reduce the temperature of the gas after cooling in the distillation tower to achieve a reduction in the top temperature of the absorption tower; at the same time, lower the temperature of the absorbent as well, thereby reducing the temperature of the gas fed into the unit after cooling. 2. Gradually increase the pressure in the absorption tower, but both temperature and pressure need to be adjusted gradually – large fluctuations should be avoided, as excessive absorption can affect the operation of the stripping tower. If the adjustments are not made in a synchronized manner, the liquefied gas may contain C2 compounds, which in turn can affect the operation of the stabilization tower
It can’t be a problem with low pressure; in our small factory, the pressure is 0.85 MPA, and the quality of the dry gas is satisfactory! Is the richness too high, exceeding the capacity of the absorption tower? It is recommended to increase the amount of rich absorption oil and to lower the temperature of the absorption tower accordingly! Personal opinion!
Reply to 3# friend788: The absorption dose has been increased to its maximum; there’s nothing that can be done regarding the temperature. I wonder if increasing the pressure will help or not?
Increasing the absorption pressure is possible, while also taking into account the operation of the air compressor.
I’m not sure what the high components in your dry gas are High carbon 5 levels require reabsorption, while high carbon 3 and 4 levels necessitate the modification of the absorbent, as mentioned by the others above
When increasing the pressure at the top of the absorption tower, you must ensure that the compressor is operating; reducing the temperature of the rich gas can also lower the temperature of the absorption tower
The content of components above C3 in the dry gas is high; increasing the pressure is one solution, but the pressure issues associated with the compressors must be taken into account. If the compressor permits, it can be increased slightly. In my opinion, the following points should be primarily considered: 1. Improving the degree of depletion of the supplementary absorbent ； 2. Reduce the top temperature of the tower or increase the heat extraction at the middle section ； 3. Adjust the oil-to-gas ratio ； 4. Maintain stable feed rates and temperatures.
Also, pay attention to the temperature at the top of the desorption tower!
Also, pay attention to the temperature at the top of the desorption tower!