High-quality insoluble sulfur fully sealed three-in-one dryer

Insoluble Sulfur (IS), a pale yellow powder,IS a linear high-molecular long-chain polymer of common sulfur, with a relative molecular mass of 30,000 to 40,000. When the degree of polymerization is greater than 200 and it is even insoluble in carbon disulfide, it is thus named. IS products are actually a mixture of IS and soluble sulfur (common sulfur), mainly used in the production of radial tires for automobiles. At present, the consumption of IS in the foreign tire industry has accounted for 40% of the total sulfur consumption and is still increasing. Driven by the rapid development of the domestic automotive industry, the rapid growth of the radial tire industry is bound to bring about a strong demand for high-quality insoluble sulfur.

The current production and demand situation and existing problems of insoluble sulfur powder

At present, the best insoluble sulfur in the world IS Crystex produced by Flexsys Chemical Company of the United States. Rona Planck Company analyzed the third-generation Crystex product for rubber and believed that this product is made from high-quality IS as raw material, supplemented with highly dispersible polymer resin and dispersant aid, and then mixed and granulated. After practical application, it is easy to disperse in the rubber compound, the performance of the products is uniform, and it is convenient to weigh and pollution-free. It has strong competitiveness in the market. It can be seen from this that high content, high stability and high dispersibility will be the development direction of IS.

High-content and high-thermal-stability IS has high requirements for production technology and equipment. Only a few countries abroad, such as the United States, Germany, Russia and Japan, are capable of producing it. At present, there are mainly three problems faced by IS in our country, including low conversion rate of IS, poor product stability and safety issues such as flammability and explosiveness.

The conversion rate of IS is low

Especially the primary problem faced by the melt method is generally improved by optimizing the synthesis conditions, enhancing the production equipment and production conditions, and seeking new catalysts, stabilizers and other methods.

(2) The problem of poor product stability

The main solution is to seek new and highly efficient stabilizers. By means of closed crushing and packaging to prevent dust pollution, and by adopting measures such as material circulation, water layer sealing, and high-boiling-point extraction liquid, the production environment is improved and the "three wastes" are reduced.

(3) Flammability and explosiveness are important issues faced in production

The main improvement measures include adopting wet method to protect the crushing device to enhance the crushing conditions of the product; Adopt various measures to eliminate static electricity and use non-toxic, non-flammable and non-explosive extract substitutes to solve the problems in the extraction process; Eliminate potential hazards in the reaction by lowering the reaction temperature of the gasification method or improving the reaction conditions (such as the melting method).

Introduction to the Fully Enclosed Continuous Production Process of High-Quality Insoluble Sulfur

Insoluble sulfur was prepared by gasification using organic hydrocarbons as the quenching liquid. Using aviation kerosene as the quenching liquid, it has a relatively high yield, and the thermal stability of the product reaches over 69%. Based on the experimental research, a pilot-scale test facility for insoluble sulfur was designed and constructed to explore the possibility of continuous preparation of insoluble sulfur by gasification.

The production process mainly includes four major parts: the raw material pretreatment process, the rapid cooling process, the post-treatment process of the product, and the waste liquid recovery process. The key process among them is the extraction and separation of soluble sulfur and insoluble sulfur: the rapidly cooled products are pumped into the three-in-one dryer by pump P-02 for subsequent treatment. As the three-in-one dryer is a multi-functional drying equipment that integrates filtration, drying and extraction. Therefore, in the three-in-one dryer, the separation of the rapidly cooled products can be completed, followed by processes such as curing and drying, extraction and purification, to obtain high-quality IS products. As the subsequent processing requires a certain amount of time, the materials need to be switched to the next three-in-one dryer. The specific process is as follows:

(1) The slurry is first fed into the three-in-one dryer SR-01 through the screw pump P-02. The solid and liquid of the slurry are separated, leaving a mixture of soluble and insoluble sulfur. During the feeding process, the material in the dryer is constantly stirred, and the extractant CS2 is introduced at a ratio of 1:3 for pre-rinsing to remove the small amount of aviation kerosene remaining on the surface and extract part of the soluble sulfur.

(2) After continuous feeding for a period of time, switch the material to SR-02 feeding. The determination of feeding time is based on the process requirements and the processing capacity of the multi-functional dryer.

(3) When feeding into the next dryer SR-02, the material in the dryer SR-01 is cured and dried at 60℃±2℃ for 6 hours. After cooling, the extractant CS2 was introduced at a mass ratio of 1:3, and the mixture was extracted and purified under stirring for 30 minutes. Dry under vacuum conditions of 60℃±2℃; The last material is discharged.

(4) Through the above operations, switches can be made between two or more multi-functional dryers, thereby achieving continuous production of high-grade IS products.

Technical advantages of high-quality insoluble sulfur fully sealed three-in-one dryer

(1) The process of producing insoluble sulfur from sulfur is rather complex, and the working conditions of each process are often different. Some require heating, while others need cooling. The fully enclosed filtration, washing and drying integrated machine developed and designed by Wuxi Srui integrates multiple unit operations in the post-treatment process of fine chemical production into one device, avoiding the leakage at the connection points caused by the large dispersion of the equipment, which leads to material and environmental pollution. The working conditions of each process are easy to meet and effectively control, and the product quality can be guaranteed Stable insoluble sulfur products with high content and high thermal stability can be obtained.

(2) The continuous production process of insoluble sulfur can complete the entire process from raw materials to products through pipelines based on material balance, which is suitable for the requirements of industrial batch production.

(3) The entire process of the new continuous production technology for insoluble sulfur is carried out in sealed pipelines, which will not cause any gaseous or dust-like pollution to the surrounding environment. It also greatly improves the working conditions of the staff and ensures safe production.

(4) The fully enclosed three-in-one filtration, washing and drying process for the recovery of CS2 and crystalline sulfur can achieve the recycling of raw materials, reduce production costs and improve production efficiency.

(5) The entire process can be controlled by sensors, automatic instruments, microprocessors and other control devices to control the temperature, pressure, CS2 concentration and other parameters of each section, ensuring the process conditions of each part of the pipeline and achieving the automatic continuous production of insoluble sulfur.