On the design calculations for water scrubbers
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Dear seniors, I would like to ask for your advice regarding the design of a washing tower. The operating conditions are as follows: medium flow rate of 1200 kg/h, which is equivalent to a flow rate of 650 Nm3/h; inlet gas temperature of 50°C; inlet gas pressure of 3–5 kPa; and HF content of 700 ppm. It is required to use a scrubber tower to wash hydrogen fluoride, with tap water at room temperature being used. The water washing tower is made of PP material, and the packing can be regular plastic corrugated plates or bulk packings such as Pall rings. The hydrogen fluoride content in the raw gas after washing is no more than 1 ppm. Since hydrogen fluoride reacts with water to form hydrofluoric acid and aqua regia, which are deadly to subsequent equipment, the lower this concentration, the better; ideally, it should be at the PPB level. I would like to ask what the appropriate diameter and height for this tower are, and how to calculate them Are there any software that is easy to get started with?
1. It must be neutralized with an alkali. 2. The efficiency in reducing the concentration from 700 ppm to 1 ppm needs to be 99.9%, which is difficult to achieve with a single washing tower. 3. The diameter of the equipment can be determined based on the gas velocity in the empty tower. 4. The height of the packing material needs to be calculated using software. 5. It is recommended to consult a professional manufacturer; you can also contact me
Water washing isn’t effective anymore. Let’s refer to Henry’s Law; a subsequent alkali washing is necessary. Apart from hydrofluoric acid, are there any other components mentioned? It’s impossible to achieve a level of 1 ppm, let alone ppb levels; water spraying or alkali spraying cannot produce such results. As for equipment corrosion, it’s best to use PP or PTFE materials. You can add me on WeChat for further discussion
The height and diameter of a packed tower can be estimated using Aspen; it doesn’t matter whether the concentration is on the ppm or ppb scale – as long as there is sufficient water volume and a sufficiently high packing height, it’s quite easy
Through monitoring here, the HF content has never exceeded 200 ppm. Can this be achieved by washing with water?
During this period of monitoring, the concentration has never exceeded 200 ppm. Since CO2 needs to be recovered, and CO2 reacts with alkalis, the alkali washing method cannot be used
The content level is 200 ppm; to recover CO2, alkaline washing cannot be used
It must be neutralized with an alkali. Soda ash can be used
Bro, I got this from your post from 2013. I didn’t expect you to be in the field of automation; it’s admirable that you’re still researching equipment related to pressure vessels after all this time