Due to the popularity of environmental protection inspections and environmental protection knowledge, many users have learned that the adsorption capacity of activated carbon reaches saturation after a certain period of use when purchasing activated carbon boxes. Risk of Departmental Penalties. Therefore, we are often asked by some rational users how do you calculate the replacement cycle of activated carbon? How often does our activated carbon need to be replaced?

1. Theoretical basis for the calculation of the life cycle of activated carbon

Adsorption equilibrium refers to that for a given system, the amount of adsorption at equilibrium is related to the temperature and the equilibrium concentration of the adsorbate in the solution.

From the factors affecting liquid and solid adsorption:

(1) Molecular polarity. Generally speaking, polar adsorbents preferentially adsorb polar solutes in non-polar solvents, and non-polar adsorbents preferentially adsorb non-polar solutes in polar solvents.

(2) Influence of solvent solubility: the less soluble the solute, the easier it is to be adsorbed

(3) Adsorption of homologues: the adsorption capacity increases or decreases regularly with the growth of carbon connection

(4) Temperature influence: The adsorption of solutes from the solution by the adsorbent is an exothermic reaction. Usually, the temperature increases and the adsorption capacity decreases, but the adsorption capacity of some substances will also increase with the increase of temperature.

In addition, the adsorption relies on molecular diffusion, and the liquid phase disorder is accelerated by stirring and shaking, which is beneficial to mass transfer.

The adsorption capacity of activated carbon is related to the pore size and structure of activated carbon. In general, the smaller the particles, the faster the pore diffusion, and the stronger the adsorption capacity of activated carbon. The pH value and temperature of the sewage also have an effect on the adsorption of activated carbon. Activated carbon generally has a higher adsorption capacity under acidic conditions than under alkaline conditions. The adsorption reaction is usually an exothermic reaction, so low temperature is beneficial to the adsorption reaction. Of course, the adsorption capacity of activated carbon is also related to the concentration of sewage. At a certain temperature, the adsorption capacity of activated carbon increases with the increase of the equilibrium concentration of adsorbed substances.

The above factors can be adjusted according to the supplier's parameters to adjust the balance maintenance.

2. Calculation formula for the service life of activated carbon

Activated carbon has different adsorption capacities (represented by S) for different organic gases. The pollutant discharging unit should first determine the replacement cycle according to the design plan of the activated carbon adsorption treatment facility. If there is no design plan or the actual construction situation is inconsistent with the design plan, refer to the replacement cycle formula T=m×s÷(c×10-6×Q×t) Calculation. :

T(d)=m*S÷(c×10-6×Q×t)

m: mass of activated carbon, unit kg;

S: 10% of the dynamic adsorption capacity (s) is the reference value. If activated carbon with a theoretical dynamic adsorption capacity of more than 10% is used, the dynamic adsorption capacity certificate obtained by the supplier's test or other proofs that can explain the source of the selected value can be provided for reference. Prove that the given values are calculated;

C: refers to the concentration of VOCs reduced by activated carbon (c) is the difference between the inlet concentration and outlet concentration of the activated carbon section measured by monitoring; *10-6 Convert mg/mg to kg/mg;

Q: Measured air volume, unit m/h;

t: working hours per day, unit h/d