Adding acid to adjust pH in industry
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1. From a technical perspective, it is necessary to adjust the pH by adding sulfuric acid; could you provide any relevant information on how this should be done? 2. It seems to be a problem ensuring uniform mixing of concentrated sulfuric acid; therefore, considering switching to dilute sulfuric acid, what is the typical concentration of dilute sulfuric acid used in industry? Preparing dilute sulfuric acid oneself seems quite dangerous – are there any good suggestions? 3. Are there any automated methods for detecting the pH after acid adjustment, or does one have to use a pH meter manually? Is it possible to achieve integration with the control room?
PH is available online, so no manual testing is required； In industry, dilute sulfuric acid is generally used, with the concentration varying depending on the requirements – 10%, 20%, 25%, etc. However, what is purchased is usually concentrated sulfuric acid, which needs to be diluted; the heat released during this process can be recovered and utilized.
It depends on what kind of process you use: Our company has two units that utilize sulfuric acid: 1. That used in production: it makes use of 95% sulfuric acid； Add directly to the water circulation pipeline ； After mixing via an online mixer, the mixture enters the reaction tank, where pH is monitored to control the amount of sulfuric acid added ； (Automatic control) ； It’s also very stable ； 2. Adjustment of wastewater pH: 50% sulfuric acid is received and stored in a tank ； Another 20% sulfuric acid storage tank ； When the 20% sulfuric acid storage tank reaches a certain liquid level ； Automatically add water to the 20% storage tank ； After reaching a certain liquid level, add the prescribed amount of sulfuric acid to it ； After that, the system automatically enters a loop for mixing ； (All quantities are controlled by the liquid level.) ； Do not take samples for analysis ；
1. In production, that also amounts to diluting concentrated sulfuric acid, right? It’s convenient to find out how blind pH monitoring is achieved – through a pH meter? 2. Does it mean mixing 50% sulfuric acid with 20% sulfuric acid? Do the two achieve different concentrations of sulfuric acid through different ratios?
1. pH meter monitoring, DCS remote monitoring； 2. Dilute with 50% sulfuric acid to obtain 20% sulfuric acid ；
We use fuming sulfuric acid. Pay close attention to stirring; add online pH monitoring for the discharged material. If the mixing effect is good, automatic single-loop control of pH can be achieved. Ours is very stable
Okay, thank you. I also talked with the design institute, and they said online monitoring is feasible; we need to take a closer look at it