Temperature increase in the LPG desulfurization and alkylation regeneration tower
Thread Content
Recently, due to maintenance work on the liquefied gas desulfurization unit, the hydrogen sulfide content in the liquefied gas used as feedstock in our plant was relatively high (around 5000 ppm). This high-sulfur liquefied gas was fed directly into the alkaline solution desulfurization system. Today, it was observed that a large amount of steam was being released from the disulfide separation tank; the temperature in the alkali solution regeneration tower was nearly 100°C. This situation has never been observed before; I would like to ask my fellow students what could be the reason? Thank you all first!
Check the alkali heater first. Generally, a temperature control is installed in the alkali solution heater. Is it the change in the medium that causes the temperature to rise? When the temperature reaches 100°C, the water in the alkali solution evaporates, which leads to a change in the concentration of the alkali solution.
The heating temperature of the alkaline solution is normal; it’s just the temperature in the oxidation tower that is high
The main chemical reaction that takes place in the oxidation tower is: 4NaRS + O2 + 2H2O → 2RSSR + 4NaOH. The heat effect of this reaction is not significant; the temperature of the alkaline solution remains normal, yet the temperature in the oxidation tower is very high. The materials that enter the oxidation tower are either the alkaline solution or air – could it be a problem with the air? Looking forward to the participation of experts!
I hope experts will participate actively. Thank you! !
What is the medium used in your heaters? Check to see if there are any leaks. Please investigate further. What was said on the 4th floor is correct; or else send over the process details so that everyone can understand what’s going on
It is mainly caused by too high a content of thiol sulfur in the raw materials; this phenomenon has occurred in my facility as well.
The main reason for the increase in temperature is the heat of reaction. Because high concentrations of hydrogen sulfide react with alkaline solutions to produce NaHS and sodium sulfide, which are then oxidized in the oxidation tower to form sodium thiosulfate; this exothermic reaction causes the temperature to rise, and the increased temperature further accelerates the oxidation reaction. Solution: Reduce or suspend the oxidation air ； Increase the frequency of alkali solution replacement.