Pollution Control in the Production Process of Reclaimed Rubber （Part 1）

The principle of thermochemical regeneration of waste tires and waste rubber is: by increasing the temperature of the phosphatized rubber, under the action of additives and oxygen, the network structure of the phosphatized rubber is destroyed, and the vulcanizability is restored, and the phosphatized rubber is regenerated. (commonly known as "desulfurization", that is, the inverse process of lemon gum phosphating).

The commonly used processes are as follows:

1. Mechanical crushing + heating in the tank (oil method, water-oil method and the currently commonly used dynamic method) + mechanical kneading

2 Mechanical crushing + other heating and plasticizing methods (extrusion, banburying, continuous screw heating, microwave heating, etc.) + mechanical kneading

Major Pollutant Sources

At present, whether heating regeneration is used in the tank or heating regeneration by other methods, the regeneration is carried out by increasing the temperature of the rubber compound. Under high temperature, low-boiling substances in waste rubber and additives will evaporate or volatilize, and will decompose to produce low-boiling substances at high temperature, and react to produce odorous substances such as two carbon-phobic and hydrophobic substances, which will pollute the environment.

To reduce the pollution of the waste rubber recycling process, the first idea is to reduce the production of pollution and control it from the source; the second is to have a feasible pollution control method.

Reduce the amount of pollutants produced

1. Choose a softener with less volatile matter and less steam.

In the recycling process of waste rubber, a certain amount of softener is often added, such as coal tar, pine tar, tall oil, aromatic oil, etc. After collection and analysis, the volatility below 220 ℃ in different softeners varies greatly, the lowest is 0.2%, and the highest is 6%. Part of the organic matter will be released in the dynamic tank exhaust, or during mechanical rubber mixing and product use, resulting in pollution. To this end, try to use softeners with less volatiles, especially coal tar.

2. Select the appropriate production process.

Heating production is carried out with a closed reaction, and the exhaust gas is discharged in the form of high concentration. For example, using a de-dredging tank to release the pressure and exhaust steam at the end of the reaction, and using an atmospheric pressure continuous plasticizer to discharge the steam in the high temperature section. The volatile organic compounds in the tire lysate and softener can be discharged in an organized and high-concentration form, which is convenient for recycling and destruction. Avoid condensation in the rubber compound and release it during mechanical rubber mixing and product use, increasing the difficulty of collection and processing. Try to use low-temperature regeneration and low-temperature differential heating. Reduce the amount of pollutants produced. When heating and plasticizing, try to increase the degree of plasticization, reduce mechanical shearing during mechanical rubber mixing, reduce

Low rubber mixing temperature reduces the amount of waste gas released in this price segment, and reduces the difficulty of collecting and treating unorganized waste gas.