Issues with the inlet temperature of the recycle hydrogen compressor and the steam consumption of the turbine in the residue hydrodesulfurization unit
Thread Content
I would like to ask everyone: as summer temperatures rise, the inlet temperature of the recycle hydrogen compressor in the residue hydroprocessing unit also increases. How can this issue be addressed? Additionally, the steam consumption of the turbine at 3.5 MPa has also increased significantly. What could be the possible reasons for this increase?
The root cause of these problems lies in the high inlet temperature of the compressor, as you mentioned. The logic is as follows: when the inlet temperature is high, the molecular weight of the components at the inlet is lower; as a result, the efficiency of the compressor decreases, and more medium-pressure steam is required. (From personal experience, the effect of steam volume is almost negligible in certain extreme cases.) ) So, what you need to do is to reduce the temperature at the compressor inlet: 1. Generally, such air-cooled systems are equipped with a wet air-cooling option, and spray water can be used. Generally, the results are quite good ； 2. Check whether there is any flow deviation in the air cooling and water cooling systems. 3. Check in the preceding process whether it is within the controlled parameters. 4. Have there been significant changes in the raw materials? The above are personal opinions for reference only!
Reduce the air cooling temperature, inspect the air cooling fins, and clean them promptly to ensure effective heat exchange
Air cooling can be considered, along with water spraying for cooling, in order to reduce the temperature of the lean amine solution； The steam consumption increases; check whether there is any change in the quality of the steam, or if it is caused by an increase in the molecular weight of the cyclic hydrogen
Analyze the purity of the recycled hydrogen; it is likely low, which in turn increases steam consumption. This is for reference only!
Has the inlet flow rate of recycled hydrogen increased?
Cold high-pressure gas and cold high-pressure oil are in a state of phase equilibrium; as the temperature increases, the hydrogen purity of the recycled hydrogen decreases and its average molecular weight increases, so naturally the steam consumption rises at the same pressure ratio. It is normal for high-pressure air cooling to encounter bottlenecks in summer; if the circulation unit cannot operate, the processing capacity can be reduced, although it is better to replace it with a larger high-pressure air cooler.
If the temperature at the inlet of the unit is high, you can: 1) Use a three-way valve to lower the temperature of the high-pressure heat exchanger, thereby reducing the inlet temperature of the air cooler from the source; 2) Contact the fitter team to adjust the rotation direction of the fan blades, increasing the angle accordingly; 3) Consider the temperature of the water used for injection – depending on whether it is a hot or cold medium relative to the outlet temperature of the air cooler, the amount of water injected can be adjusted appropriately; 4) If there is an excess of light components, consider whether the reaction depth is too great or if the raw materials are too light in composition; 5) Since the reactor has cold hydrogen, increase the temperature rise in the upper layer of the bed and reduce the temperature in the lower layer; 6) Reduce the speed of the circulation pump to decrease the amount of circulating hydrogen; 7) As a last resort, spray water on the air cooler or clean it. The reason for high steam consumption is the high load on the unit. You can: 1) increase the discharge of circulating hydrogen to improve its purity; 2) reduce the rotational speed to lower the amount of circulating hydrogen, thereby maintaining the hydrogen-to-oil ratio and hydrogen partial pressure; 3) reduce both the flow rate and the load. Hope this helps you
The eighth floor’s explanation is very comprehensive; great. Reduce the circulating hydrogen temperature to around 40, and increase the variable frequency of the high-pressure air cooler. Contact the dispatcher to lower the temperature of the lean liquid. It is also possible that the reaction depth becomes too intense, resulting in an increase in alkanes in the recycle hydrogen and thereby reducing the reaction depth.
The eighth floor’s explanation is very comprehensive; great. Reduce the circulating hydrogen temperature to around 40, and increase the variable frequency of the high-pressure air cooler. Contact the dispatcher to lower the temperature of the lean liquid. It is also possible that the reaction depth becomes too intense, resulting in an increase in alkanes in the recycle hydrogen and thereby reducing the reaction depth.
The eighth floor’s explanation is very comprehensive; great. Reduce the circulating hydrogen temperature to around 40, and increase the variable frequency of the high-pressure air cooler. Contact the dispatcher to lower the temperature of the lean liquid. It is also possible that the reaction depth becomes too intense, resulting in an increase in alkanes in the recycle hydrogen and thereby reducing the reaction depth.