The speed of the cyclic hydrogen compressor is slowly decreasing! What’s the reason?
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Operating conditions: System pressure at 140 Bar; cycle hydrogen compressor speed at 11,000 revolutions per minute, gradually decreasing to 10,180 revolutions per minute over two months. When the speed is increased, the high-pressure steam main valve of the turbine activates. The speed remains constant from 85% (corresponding to 10,180 revolutions per minute) to 100%; reducing the speed to 85% also results in no change. Steam pressure stays at 30 Bar, temperature at 318 degrees, and back pressure at -0.80 Bar – no significant changes occur. The system pressure drop is 0.35 + 3.45; there are also no notable changes in the new high-pressure heat exchanger or the new high-pressure air cooler. The concentration of cycle hydrogen is 95%–96% H2. The shaft displacement of both the compressor and the turbine is 0.09 mm, with vibration levels of 0.26 mm, which are within normal ranges. Consequences: The amount of circulating hydrogen decreases, the hydrogen-to-oil ratio drops, the crude oil processing load declines, and most importantly, the rotational speed continues to fall.......
1. Check whether the liquid level in the gas-liquid separation tank is normal; go to the site for an actual verification to prevent false liquid levels and avoid the compressor operating with liquid inside. 2. Inspect the turbine throttle control of the circulating hydrogen compression unit
First, I ask: does your steam volume change from 85% to 100%?
The steam volume remains at 9.2 tons without any increase, and more than 85% of the main steam valve stems respond.
The reason for no increase between 85% and 100% is likely due to a limit on the available capacity. The main steam valve functions like a control valve; when more air is supplied, the speed increases. As for the gradual decrease in speed, it is necessary to analyze the properties of the medium as well as the changes in steam parameters before and after the speed decreases
1. The liquid separation tank indicates 5.6% (a two-out-of-three interlock level), but it’s a good reminder – false signals are still possible! 2. The throttle pressure changes, the valve stem also moves, and its travel can reach 100%; however, the speed does not increase nor does the amount of steam increase.
1. The liquid separation tank has a 5.6% setting (two-out-of-three interlock); however, it’s worth noting that false signals may occur! 2. The oil pressure responds, and the valve stem moves more than 85% of its full stroke, but the rotation speed remains unchanged and the steam production does not increase.
Could the fouling on the turbine fins be due to issues with the quality of the steam?
Has the turbine formed salt deposits? ? ? How is steam quality controlled on a regular basis?
1. The issue of salt accumulation on the impeller is currently unknown; it will have to be checked during future maintenance. 2. For steam quality control, check the boiler water: pH 9.0, sodium ions ≤8000 pmm, phosphate ≤3000 pmm. With the same steam, both the reforming cycle machine and the disproportionation compressor operate at 11,000 rpm with no issues.
It’s possible that salt has accumulated in the inlet duct of the quick-shut valve; if there is a filter at the inlet, it might also be clogged. In any case, there is an issue with the quality of the steam