Development trend and test method of coal-based activated carbon

According to the statistics of the world's authoritative "Chemical Economics Handbook Market Research Report", the production of activated carbon in traditional developed countries such as the United States, Japan, and Europe has gradually decreased. This situation has been particularly evident in recent years. Among them, medium and low-grade varieties are rarely or basically not produced.

In contrast to its market demand, due to the continuous expansion of the application of activated carbon, the application range of activated carbon is also deepening, especially in the automotive industry, solvent and waste gas recycling industry, air purification industry, food industry, water treatment and other industries, the demand for activated carbon in developed countries. There has been a steady increase in production over the past few years.

According to CEH's forecast, in the first 10 years of the 21st century, the demand for activated carbon in developed countries will be a steady and small increase. By 2011, the annual growth rate of activated carbon consumption in the world is expected to be 3% to 4%. Therefore, a large number of medium and low-grade activated carbon in China has the opportunity to fill this market gap.

The main production process of powdered activated carbon:

Generally, coal-based powdered activated carbon is produced in the form of other types of activated carbon by-products. In the case of separate production, the bulk raw coal is first crushed and sieved into raw coal powder of acceptable size according to the production process requirements, and then carbonized and activated. The finished powdered activated carbon is obtained.

Coal-based powdered activated carbon is mainly used for upper and lower water treatment, waste incineration flue gas purification treatment and soil improvement. Because of the low market price, it is often not economically feasible to produce coal-based powdered activated carbon separately. There is no manufacturer of coal-based powdered activated carbon. At present, coal-based powdered activated carbon products are basically derived from the undersize produced by coal-based granular activated carbon producers at the same time as the production of granular activated carbon, and these undersize materials are ground into powdered powdered activated carbon for sale as a by-product. At present, the foreign coal-based powdered activated carbon production company only Norit let the company, the company uses peat to produce coal-based powdered activated carbon for the purification of waste incineration flue gas.

There are three methods for deriving the adsorption isotherm equation based on the respective models of activated carbon.

The kinetic method derives the equation based on the principle that the adsorption rate is equal to the desorption rate under adsorption equilibrium conditions.

Statistical methods because the adsorption process is a state equation for a gas on a solid surface. It reflects the equilibrium state. The equilibrium constant is equal to the ratio of the partition function of each molecule to the total partition function of the molecule. The equation is obtained according to the equilibrium constants of different concentrations.

Thermodynamic Method This method was proposed by Gibbs in 1878. He defined the adsorption equilibrium to define the thermodynamic equilibrium between the pseudo-adsorbed molecules (called the adsorbed phase) and the solution phase, and the free energy was changed to zero.

Test method for coal granular activated carbon -

The measurement standard of particle size stipulates the content of the coal particle size side activated carbon, the side steps and the measurement results. The standard is applicable to the determination of the particle size of coal granular activated carbon.

1, method summary

A certain amount of purified water is sampled by using a coal granular activated carbon sample on a vibrating screen, and the mass of the sample remaining on each sieve layer as a percentage of the mass of the original sample indicates the particle size distribution of the sample.

2, measuring step

a. According to the technical requirements of the product, select a corresponding set of sieve layers, arranged according to the size of the mesh holes, arranged from top to bottom, and placed on the vibrating screen machine.

b. Weigh 100 g of the sample into the uppermost sieve of the vibrating screen, cover the sieve cover, and fasten the complete sieve. Start the vibrating screen and start the timer (or bully stopwatch) at the same time.

c. Vibrating screen (600 ± 10) s.

d. Loosen the shaker clip, take off the screen cover, gently remove the layers in turn and collect the samples in each layer separately. The activated carbon stuck on the sieve hole is gently shaken by a screen frame or brushed, and also sieved on the sieve layer.

e. Weigh each sieve layer and the screening quality in the chassis (accurate to o.1 e),

f. Repeat steps s. l to s. 5 and make another sample.

3. Calculation formula of particle size of coal granular activated carbon:

Li(%)=mi/m×100%

The mass fraction of the Li-i layer particle size in the formula, %;

Mi—the mass of the sample on the i-th layer sieve, B:

M—the mass of the original sample, g.