Low-pressure gas, the solubility issue of MDEA in dry gas desulfurization systems
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This unit is a diesel hydrogenation plant that uses MDEA for the desulfurization of recycle hydrogen, light gas, and dry gas, and is equipped with a solvent regeneration system. During routine inspections, it was found that the liquid level in the MDEA tank often dropped, requiring the addition of water (deionized water), while no MDEA was added. This should indicate that as the regeneration system operates, the moisture content in MDEA continues to decrease? Has anyone had a similar experience? What is the original? The temperature at which the entire regeneration system is in contact with the outside environment is around 40°C – why is water lost so quickly?
It is recommended that the original poster check the ethanolamine concentration; if water evaporates, the concentration should increase
Well, the moisture has evaporated. It’s now impossible to find where the water is lost.
As water evaporates, the solvent concentration increases. Check the outlet of the reflux pump to see if there is any acidic water flowing toward the collection tube; it’s possible that some of this acidic water does not return to the regeneration process
A drop in the liquid level is a normal phenomenon; our system also replenishes water frequently. There is solvent loss, as well as entrainment of solvent foam gases
1. Check the location of the temperature measurement points to determine whether there is a possibility of a discrepancy with the actual temperature. 2. Check whether there is any risk of internal leakage in the lines used to discharge sulfur-containing wastewater. 3. Check whether the temperature of the regenerated acid gas reflux tank is too high
The temperature of the regeneration reflux tank for MDEA is high, or there is a wiring issue at the outlet of the reflux pump
In the MDEA desulfurization and regeneration unit, both water and MDEA are lost. The main pathways of loss: 1. Carryover of liquid droplets from the top of the MDEA tower; when the size of these droplets is in the order of 10^2 microns, separation of such droplets can be achieved through gravity sedimentation, and they accumulate in the return line at the bottom of the downstream transport pipeline for the process gas ； Liquid droplets and bubbles smaller than this size are carried by the process airflow to downstream systems, resulting in losses, and it is difficult to separate them through gravity settling. 2. From the top of the MDEA flasher and the KO tank, liquid droplets are entrained along with the vent gases; when the size of these droplets is in the order of 10^2 microns, gravity settlement enables the separation of such droplets, which are then collected in the flasher and the KO tank ； Liquid droplets and bubbles smaller than this size are carried away by the exhaust gas flow and lost from the system, making it difficult to separate them through gravity sedimentation. In MDEA units, the MDEA and water must be added in the proportions specified in the original process operating system; otherwise, the desulfurization efficiency will gradually decrease. This can be confirmed by measuring the MDEA concentration. In the MDEA units designed in recent years, in order to achieve 1) prevention of loss of the MDEA solution and thus reduction of operating costs ； 2) Ensure the stable, continuous, and efficient operation of the MDEA system for desulfurization ； 3) To achieve objectives such as reducing the pressure drop in the pipelines downstream of the process gas and minimizing equipment operation failures, high-efficiency gas-liquid separation element sets designed using specialized dynamic separation techniques are typically installed in locations such as near the process gas outlet pipe on the inside of the top of the MDEA absorption tower, near the flash gas outlet pipe on the inside of the top of the MDEA flash tank, and within the inert vent KO tank at the top of the regeneration tower. This inner component set for high-efficiency gas-liquid separators features the ability to effectively separate MDEA droplets and mist carried by air currents, with advantages such as high efficiency, low pressure drop, low operating and maintenance costs, no need for maintenance, and a service life of 20 years without interruption. You can look up the technical parameters of the feather-leaf high-efficiency gas-liquid separator for further information.