Control of C3 content in dry gas sample
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Operating conditions of the absorber in our plant: 26 tons per hour of crude gasoline as the absorbent, with a temperature of 36.5°C； 32 tons per hour of supplementary absorbent, at a temperature of 27.1 ； The rich gas feed temperature is 28.3 ； Absorption column: extraction temperature 35.3, return temperature 24.3 ； No. 2 Middle School extracted 26.3, returned 21.3 to the tower ； The temperature at the top of the tower is 29.1, and the pressure is 0.95 MPa; the temperature at the top of the reabsorption tower is 14.6. The content of components above C3 in the dry gas sample must be kept below 3%. Under the same operating conditions, the level of components above C3 was found to be above the specified limit in four consecutive days after sampling and analysis (excluding any human error during sampling). Which parameters need to be adjusted in order to reduce this level?
Start with the valve; consider whether there has been a change in the reaction, and whether it is stable. Increasing the pressure in the absorption tower could be considered. . . . . . . . . .
Check carbon 4 and carbon 5 to determine whether there is a problem with transportation or absorption, and then make adjustments based on the specific situation.
As the fellow sailors have said, we should first identify the problem at its source; if operations remain stable, it is likely that there has been a change in the raw materials or in the parameters of the reaction process. Secondly, the key parameters of the absorption stabilization system, in the opinion of the expert, are the parameters of the absorption tower, or rather, the flow rates and temperatures at stage one and stage two. Furthermore, analyze whether the C2 content in the liquefied gas exceeds the limit, in order to determine if it is a problem related to the operation of the separation tower. Finally, examine the components of the stabilized gasoline; if there is no issue with separation, attempting to increase the amount of stabilized gasoline fed into the absorption tower might be advisable.
It seems that your data shows low temperature and pressure; our pressure is usually around 1.1 megapascals, with the temperature being in the 30s degrees
Based solely on the data you provided, if the tower is not overloaded, the temperature is already very low, so the pressure can be increased a bit more. Check whether there is excessive desorption, which results in a large amount of desorbed gas circulating within the system; an overloaded absorption load can also affect the efficiency of absorption. There’s a chance to send the dry gas and desorbed gas samples, but the conditions provided are too limited
The pressure is a bit low; isn’t a lower temperature favorable for absorption?
The dry gas composition is as follows: H2: 28.15; Air: 11.04; Methane: 20.01; Ethane, Ethylene: 33.48; Propane: 1.16; Propylene: 0.47; Isobutane: 1.09; Butenes: 0; n-Butane: 0.15; Butene-1, Isobutylene: 0.061; 2-Methylbutene: 0.31; 2-Pentene: 0.28; Total Pentanes: 0.9; C6: 0; H2S: 0; CO2: 0; CO: 2.35; N2: 0. The content above C3 is 4.97
This situation occurs from time to time; sometimes the results are satisfactory and other times they are not
The pressure at the top of the tower is a bit low; currently, the new designs use a pressure of around 13 kilograms. Increasing the operating pressure slightly can improve the absorption efficiency