Result background:

Insoluble sulfur (IS) is an allotrope of sulfur, but it is insoluble in carbon disulfide. With the increasingly strict environmental protection regulations and fuel cleanliness requirements, the amount of ordinary sulfur recovered in oil and natural gas processing, coal chemical industry, power, metal mining and other industries continues to increase, and ordinary sulfur is facing market saturation.

my country's automobile tire output ranks first in the world. As an indispensable special vulcanizing agent for radial tire production, the market price of insoluble sulfur is nearly 15 times that of ordinary sulfur. The development and production of IS, a deeply processed sulfur product, can not only greatly increase the added value of the product, but also solve the problem of environmental pollution.

At present, high-temperature gasification methods are mostly used to convert sulfur into insoluble sulfur in industry, but this method is flammable, explosive and consumes a lot of energy. Therefore, low-temperature melting methods have attracted people's attention in recent years. Because carbon disulfide has good solubility in ordinary sulfur, low price, and convenient recycling, CS2 is currently used as an extractant to purify the product regardless of high temperature method or low temperature method. However, CS2 has a low boiling point, extremely high volatility, is flammable and explosive, and is very toxic. The loss in the production process reaches 10-20%, which makes IS production face severe safety and environmental protection problems. The high temperature stability (120℃/15min) of most domestically produced IS products is less than 40%, which is far from similar foreign products. Therefore, nearly 70% of high-quality IS products rely on imports.

At present, except for foreign Flexsys brand IS products, which account for nearly 90% of the global market, the quality of other IS products is difficult to compare with it. The existing production process consumes a lot of energy, is seriously corroded by equipment, is flammable and explosive, and the carbon disulfide solvent used for extraction has quite prominent safety and environmental protection problems.

Technical advantages:

At present, we have carried out many years of research in this field and achieved the following results:

Using recovered sulfur from refining enterprises as raw material and adopting a low-temperature (less than 300℃) melting process method, the yield of sulfur polymerization and conversion into insoluble sulfur can reach more than 40%, which is a high conversion rate in the low-temperature melting process method.

In response to the outstanding safety and environmental protection problems of the existing CS2 extractant widely used in IS production, we have developed a new type of extractant that has good extraction effect (the best extraction effect is currently except CS2), is safe, environmentally friendly, and easy to recycle, and is expected to replace CS2. The extractant has become a major breakthrough in the production technology of insoluble sulfur and is the first at home and abroad.

In view of the common problem of low thermal stability in domestic insoluble sulfur products, a series of high-temperature thermal stabilizers in the production of insoluble sulfur have been developed, which makes the thermal stability of IS oil bath method reach more than 50% at 120 ° C and 15 minutes., close to foreign products and leading the country.

Application prospects:

At present, China mainly uses high-temperature methods to produce insoluble sulfur. Although the production capacity is close to 50,000 tons, most products can only be low-end products because of the large gap between their high temperature stability and similar foreign products. The insoluble sulfur products developed in this project have a thermal stability of more than 50% in 15 minutes, which is close to foreign products and leading the country. Moreover, the energy consumption in the production process is lower than that in the temperature method, and the safety and environmental protection are higher than that in the high temperature method.