The circulation volume of the hydrocracking cycle hydrogen compressor has decreased
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After the maintenance and once operations resumed normally, the circulation rate decreased by 20,000 to 30,000 standard cubic meters per hour; it was previously around 70,000 to 80,000. The system pressure remained normal. By observing the trends, it was found that this was related to the amount of steam entering the turbine and the opening degree of the control valves. However, the circulation rate should be related to the system pressure. What could be the reason for this? Since both the inlet and outlet circulation rates have decreased significantly, instrument failures can be ruled out. . .
The function of recycled hydrogen is to remove the heat generated by the reaction and maintain the hydrogen partial pressure; if the amount of recycled hydrogen decreases, does that mean the system is operating at a reduced capacity?
Are the operating parameters the same? Device load, system pressure drop, unit speed
Observe the system pressure drop~~~~
The relationship between flow rate and pressure is minimal, right?
Pressure is closely related to the amount of fresh hydrogen, while the amount of recycled hydrogen has little impact. If the speed of the turbine remains constant, then the amount of recycled hydrogen stays fixed. A higher purity of fresh hydrogen also results in a lower amount of recycled hydrogen. Other possible causes include blockages caused by ammonium salts in the system, high pressure drops, partial blockages in the filters at the recycled hydrogen inlet, coking in the furnace tubes, and coking of the catalysts.
If everything is normal, there should be a problem with the system
The current processing capacity is about 10 tons higher than before; the amount of new hydrogen supplied has increased by four to five hundred cubic meters. The speed of the turbine has risen by 1,000 revolutions, and there has been no significant increase in system pressure drop. The pressure difference across the filter at the inlet of the recycle hydrogen pump is also low. Currently, the temperature rise in the catalyst bed is small, and the control level of the cracking bed is low. Could it be that this is why less heat needs to be removed, resulting in a lower circulation rate? . .
The composition of the recycled hydrogen is also related to the circulation volume
As the processing volume increases, the pressure drop in the recycle hydrogen system rises (the pressure difference between the inlet and outlet of the recycler increases), and the recycle rate decreases