Analysis of the causes of pressure difference fluctuations in the burner of a water-coal slurry gasifier
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The burner pressure difference dropped from 0.36 to 0.12, and returned to normal after about 90 minutes; during this period, the slurry pump operated normally, the subsequent systems functioned properly, and the gasifier was operating as usual. Please analyze the reasons
Additional note: After the burner was in operation for 30 days, fluctuations occurred even after it was shut down and replaced with a new burner
If 120 is the low point and there are frequent fluctuations, check the coal slurry to see if there are any impurities. Also examine the drum screen of the coal grinder; after shutting it down, inspect the check valve and gaskets of the high-pressure coal slurry pump
In our plant, fluctuations in the slurry flow rate have led to a high oxygen-to-coal ratio, and even local flash explosions have occurred. As a result, the burner pressure difference decreased before returning to normal, but only for a short period of time – not as long as in your case. We suspect that in your plant the issue is caused by a lower concentration of the slurry.
A decrease in concentration leads to lower viscosity, reduced internal friction and pipe friction, increased fluid flowability, and lower pressure at the pump outlet. The flow rate formula is Q = A·U. According to him, the flow rate remains constant, meaning U does not change. If the concentration decreases, the velocity must increase, which creates a contradiction.
Okay~ but all the coal slurry data are within the acceptable range
Our slurry concentration is around 62~
The burner pressure difference is fluctuating, dropping as low as 0.12 – is it declining steadily to 0.12? It is also possible for a burner that has been in operation for 30 days to experience abnormal pressure differences due to wear, and the reason for this is poor quality of the coal slurry. To assess the quality of coal slurry, one needs to consider not only its concentration but also its viscosity and particle size. Additionally, it is indeed necessary to check the slurry pump; if there are issues with the slurry pump’s function of creating slurry, the outlet pressure will fluctuate, which in turn will cause fluctuations in the pressure difference at the burner.
What are the viscosity-temperature properties of your coal? Has any slag appeared? (The ash melting point should be quite high, right?) Has there been any change in the pressure difference at your slag outlet?
Q=A.U. The slurry flow meter is an electromagnetic flow meter; the value calculated over time represents the flow velocity. The flow rate is determined based on this flow velocity. When the flow velocity remains constant, it is the properties of the slurry such as concentration, particle size distribution, and viscosity that can cause fluctuations in the pressure difference at the burner.