Regarding the issue of ammonia absorption
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Our company uses vapor dome deamination, whereby the material is sprayed downward while steam rises upward under vacuum. The ammonia gas that emerges is then absorbed by an acid solution in an ammonia absorption tower. I would like to ask whether the acid solution, while absorbing ammonia gas, will also absorb water vapor as well (and if so, to what extent?) ). PS: The density of the acid solution after absorbing ammonia is sometimes higher than before absorption, and sometimes lower. The acid solution is sulfuric acid (with a concentration of about 2% by mass). What is the reason for this? By the way, what affects the efficiency of ammonia absorption? :)
Experts, come on... :)
Spraying involves heat exchange; as the temperature changes, the vapor condenses. When the condensed water falls, it affects the concentration of the acid solution, which in turn affects its density! ! This amount of condensation is related to temperature; the lower the temperature, the more water vapor condenses. Absorption efficiency is mainly related to the contact area and concentration. The smaller the droplets produced during spraying, the higher the acid concentration, resulting in faster absorption and a higher absorption efficiency. Therefore, it can be improved by adjusting the spraying effect – for example, by increasing the pressure of the spray to turn the water droplets into smaller mist particles.
DDDDDDDDDDDDDDDDD!!!!
It is recommended to use a packed tower for absorption； The large change in the density of the acid solution is likely due to the presence of water vapor; check whether the steam consumption and the effluent from the absorption tower are normal.
It is possible for the density to decrease, mainly because water has entered the acid solution. The spraying device should be checked.
Since the acid concentration is only around 2%, it proves that the ammonia concentration in the feed solution is very low; heating and vacuuming have caused a large amount of water to be introduced. The gas membrane support process (also known as membrane permeation absorption, which essentially combines two towers – a stripping tower and an acid absorption tower – on a microscopic level) provides the maximum driving force for mass transfer and thus the highest rate of ammonia removal. First, the pH of the feed solution is adjusted to above 11. A hydrophobic microporous hollow fiber membrane is used; the ammonia-containing saline solution flows on one side of the membrane, while dilute sulfuric acid or dilute hydrochloric acid (which are non-volatile) flows on the other side. The highly volatile free ammonia passes through the gas membrane and is chemically absorbed into the acid solution, thereby achieving concentration enrichment. The ammonia removal rate can reach 90–99%, and this rate is independent of the initial concentration of the feed solution. Advantages: It is extremely effective and suitable for the recovery of ammonia at low or very low concentrations (10–1000 ppm), allowing the effluent to meet regulatory standards. The process has a high driving force, the equipment is compact and efficient, and no heating, pressurization, or vacuum operation is required. Disadvantage: The main concern is membrane leakage, as that would render the entire process ineffective. We provide ready-made equipment. The micropores in our membranes are circular holes with a diameter of 0.02 micrometers, which gives them better operational stability compared to the pores in membranes produced by stretching methods (0.2x0.02 micrometers). We also have membrane systems with dual redundancy – one membrane module contains two sets of membranes, so even if one set fails completely, it doesn’t matter; as a result, the incidence of accidents is reduced by dozens or even hundreds of times. I don’t mean to ask you to stop the tower to buy a membrane; I’m just using your post to share some thoughts. I have been experiencing this process since I was working on my doctoral thesis in 1988, from China and Europe all the way to the United States, and it continues to this day. Now I have to go back to my hometown to work again.