15- Solutions for blockages in the scrubber and demister of the heavy oil catalytic regeneration flue gas desulfurization tower, as well as for the issue of water droplets falling around the chimney
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This post was last edited by luoli519 on 2020-1-4 at 11:02. Recently, several large state-owned refinery companies have reported that their projects utilize process packages from a foreign company, while the detailed design of the separation units is carried out by the design institutes within these same companies. However, the separation device is not working effectively at present; acid rain or alkaline rain often falls in the area around the chimney, turning the surrounding land white as if it were saline-alkali soil, thereby severely polluting the factory and the surrounding environment. The owner also requested the design firm and the manufacturers of the separation equipment to make corrections, but after several years of repeated efforts, no effective solution to the problem was found. Please share the actual operating conditions of your respective devices as well as the countermeasures taken.
It’s also raining on the chimneys here, but it’s not acidic or alkaline rain. I suppose it’s understandable that as long as the pH level in the desulfurization tower is kept under control, the phenomenon you mentioned won’t occur
With the WGS process, as long as the amount of alkali solution added is appropriate and the pH is well controlled, with no situation of excessively high pH or excessive alkali addition, alkali rain will not occur. Acid rain is the same. Personally, I think it’s mainly a matter of operational adjustments. Design issues come second. Since the process package selected is a relatively mature one, the design institute approaches the breakdown of this package with a sense of responsibility, and discusses any doubts or concerns it has with the supplier of the process package.
There is no issue with the main process; the problem lies in the details. If one unit has a problem, it’s a individual issue, but if several units experience similar problems, then it’s a common issue. In my opinion, the mist removal details aren’t well-designed, or the original design wasn’t thorough enough; it’s common for conventional mechanical mist removers to fail to meet the requirements. It’s necessary to use mist removers with higher separation precision, such as wet electrostatic dust removal mist removers or ridge-type mist removers.~~~
This post was last edited by luoli519 on 2020-5-22 at 13:33. This process involves using an alkaline solution to circulate and wash flue gas; the operational requirements specify the concentration of the alkaline solution as well as the amount of liquid used for spraying, and they also indicate the chemical names of the alkaline substances. As required by the manufacturing process, a large excess of alkali is used. If the efficiency of gas-liquid separation and foam removal in the exhaust gases is low, the excessive alkaline liquid droplets present in those gases will be emitted, leading to the phenomenon of \"alkali rain\" – this is one of the most common issues encountered in factories. If the concentration of the washing alkali solution is low and the amount of liquid used for washing is insufficient, the acidic gases carried in the incoming flue gas cannot be completely absorbed during the washing reaction. Additionally, if the efficiency of gas-liquid separation and foam removal before flue gas emission is low, the exhaust gases released from the chimney will contain a large amount of acidic liquid droplets and mist, which can also lead to the formation of \"acid rain\". Similar phenomena have also occurred in foreign factories. The problem may lie in: 1. The washing and absorption processes were not carried out strictly in accordance with the specified procedures ； 2. Serious problems exist with the internal components for gas-liquid demisting or with the design itself. These two reasons are responsible for the \"rain falling from\" the WGS chimney at the factory.
This post was last edited by luoli519 on 2018-5-17 at 11:43. The flue gas in question here is from catalytic processes in refineries, not from power plant boilers; therefore, the wet electrostatic dust removal and mist removal methods, as well as the FLAT and ROOF types of mist eliminators used for power plant flue gas, are not suitable for the demanding and precise desulfurization required for catalytic flue gas in refineries. Please note the difference between the two.
Why is the ROOF ridge-type demisting system not suitable for the rigorous and precise desulfurization of catalytic flue gases in refineries? How to explain it? It’s hard to understand~~~
Acid rain falling on chimneys must indicate some changes in the flue gas. I work on projects related to chimney construction and maintenance, so it seems I can only wait for someone more knowledgeable to answer this question
I would like to ask what type of industry conference it is – one related to catalytic cracking or specifically to flue gas desulfurization?
In the case of acid rain, you can check the SO3 content in the flue gas after treatment; if it’s high, then measures should be taken to reduce it. For alkaline rain, it’s necessary to control parameters such as the pH value of the liquid used in the scrubber tower, to ensure that the alkaline solution doesn’t exceed specified levels – this way, there won’t be any substances carried out of the top of the tower. If it’s still there, it’s likely that there’s a problem with the packing or other internal components of the chimney.