Chlorine control
Thread Content
There is a reaction that involves the use of chlorine gas; if too much chlorine is used, the reaction will fail. So how can excess chlorine be prevented in actual production?~
High-risk reactions all use dual flowmeters, with orifice plates and vortex street sensors. One control regulating valve, one control shut-off valve. The question is, is your process that dangerous?
It’s either dangerous, or if too much is used, the entire reaction fails
{:3_49:} Find your overload point and then leave some margin – just buy imported equipment; if you have the money, install two sets of flow meters to cross-verify each other’s readings
Is it continuous feeding or batch feeding? You could consider having an excess of another material
To give an example, when producing hydrogen chloride, it is necessary to control the excess amount of hydrogen. There are two key points for control: 1) The volume flow rate (i.e., the amount in terms of moles) of hydrogen chloride should be maintained within a range of 1:1.1 to 1:1.25; keeping it within this range prevents excessive chlorine formation. 2) The purity of hydrogen chloride should be kept between 97% and 99%. The purpose of controlling this is to avoid wasting hydrogen and to prevent excessive chlorine formation (this was something I learned when I was working as an operator right after graduating). When the purity of hydrogen chloride is measured to be 100%, a potassium iodide solution is used for a qualitative test (I think it’s potassium iodide), and then it is determined whether the chlorine valve needs to be adjusted. This is the entire process of controlling chlorine gas. Another example is the chlorination reaction, etc.; the ratio for this reaction needs to be determined based on your specific reaction. To prevent perchlorine from forming, another substance needs to be used in slightly excess; the feed amounts of both substances must be determined, and there must also be a monitoring process.
The example on the 7th floor is very good; for instance, in the synthesis of sodium hypochlorite, there is always an excess of base involved.
May I ask, when synthesizing sodium hypochlorite, do you use a pH meter or titration to determine the endpoint?
When you talk about controlling excess amounts, is it by weighing or by volume?
I’m not sure if this is a hypothetical question or if such a product actually exists. If excess is understood in this way, before the reaction reaches its completion, due to the introduction of chlorine gas, there is a local excess of chlorine gas at the gas-liquid contact surface – does this have any impact?
Relatively clumsy, but still relatively safe, titration control!