On January 21st, the technology development and demonstration project of waste sulfuric acid-gypsum resource utilization passed the identification of scientific and technological achievements organized by the China Petroleum and Chemical Industry Federation. This achievement solved the two major problems of waste sulfuric acid and industrial by-product gypsum. This achievement is the first of its kind at home and abroad in waste sulfuric acid-gypsum joint acid production, and the overall technology has reached the international advanced level. CNC Lathe With Linear Guideway Flat Bed Cnc Wood Lathe,Flatbed Cnc Lathe,Cnc Automatic Lathe,Linear Guideway Cnc Lathe Ningbo junfa CNC Equipment Co. Ltd. , https://www.junfacnc.com
Experts from the Chinese Academy of Engineering Jin Yong and other experts have suggested that the technical parameters of the process be further optimized and the scope of application expanded.
The appraisal committee believes that the project, based on the study of the characteristics and decomposition characteristics of industrial waste sulfuric acid such as alkylation and titanium dioxide, will innovatively couple the waste sulfuric acid decomposition with the gypsum-sulfuric acid and cement process, and develop waste sulfuric acid-gypsum combined production. Sulfuric acid complete set of process technology realizes the economic recycling of waste sulfuric acid and the utilization of waste gypsum, and has achieved good economic, social and environmental benefits.
It is understood that China's sulfur resources are seriously lacking, and the dependence on sulfur imports has reached 60%, accounting for 37% to 40% of the world's sulfur trade. Sulfur resources have severely restricted the healthy development of the sulfuric acid industry and the extended industries in China. Moreover, in our country's sulfuric acid production, sulfuric acid produced from sulfur, pyrite, and smelting flue gas accounts for more than 98% of the total sulfuric acid production, and sulfuric acid produced by the thermal cracking of gypsum and waste acid accounts for less than 2%. At the same time, China's annual waste sulfuric acid emissions have approached 20 million tons. The current thermal cracking treatment methods are not only expensive but also costly. The cost of sulfuric acid production is between 650 and 680 yuan/ton. According to statistics, in 2013, the amount of gypsum produced in China’s industrial by-products was over 184 million tons, subject to resource utilization technologies, economic conditions, and other restrictions. At present, about 52% of industrial by-product gypsum is piled in China, and its cumulative stockpile exceeds 5 Billion tons.
In order to solve the problem of large and intractable production of waste acid and waste gypsum in China, the Lubei Group combines the gypsum and sulfuric acid co-production cement plant, and uses its rotary kiln to conduct research, testing, technological transformation and long-term trials of pyrolysis industrial waste sulfuric acid. Burning, the device to maximize the alkyl sulfate waste sulfuric acid and other waste acid, the two kiln waste sulfuric acid spray total control at 32 tons / hour, sulfuric acid production costs only 275 yuan / ton. The investigation of science and technology reveals that there are no reports of the same literature in the project at home and abroad.
At present, the company has built a 240,000 tons / year of waste sulfuric acid - 600,000 tons / year gypsum joint production of sulfuric acid, cement clinker industrial installations, and has been running for a year. Researchers improved the concentration of SO2 in the kiln gas and reduced the production cost of sulfuric acid by continuously optimizing the ratio of raw materials and technological parameters. The new type of waste sulfuric acid spray gun was successfully equipped on the rotary kiln for the decomposition of gypsum raw materials and achieved many improvements. The point of stable injection of acid, waste sulfuric acid decomposition rate ≥ 99.95%, gypsum decomposition rate ≥ 98.5%. The project has now achieved 400,000 tons of sulfuric acid and 300,000 tons of cement per year.
The annual emission of waste sulfuric acid in China is nearly 20 million tons. Most people think that the exhaust emission of motor vehicles contributes 20% to 30% to PM2.5. Therefore, many domestic and foreign refineries tend to produce more high-octane gasoline to reduce Exhaust emissions to the environment. In order to improve the quality of gasoline, refineries need to add light hydrocarbon oils formed after the alkylation of liquefied gas. This process usually uses concentrated sulfuric acid as a catalyst, which is subjected to purifying washing and absorption. The concentration of sulfuric acid is gradually reduced, and 0.1 ton of waste sulfuric acid is produced for each ton of hydrocarbon oil produced. Due to the domestic sulfuric acid alkylation unit, the annual amount of waste sulfuric acid discharged from alkylation exceeds 1 million tons, which is increasing year by year. In addition to 80% to 95% of sulfuric acid, waste sulfuric acid contains 3% to 8% of organic matter. The alkylated waste acid is black and sticky, highly corrosive, and has a great harm to the environment. It has no re-use value and must be disposed of. In addition to titanium dioxide waste acid, pickling waste acid and other industrial waste sulfuric acid, the current domestic waste sulfuric acid emissions nearly 20 million tons.
The world's major companies have made long-term and extensive researches on the treatment of waste acids. There are several mature technologies and some have already achieved industrialization. Starting from the purpose of regenerating, purifying, and utilizing waste sulfuric acid, they dealt with waste acids. The main forms of utilization include direct utilization, recovery of sulfur resources, and regeneration of organic decarbonization.
At present, the most popular treatment method is to recover the sulfur resources in spent sulfuric acid in the form of sulfur trioxide, sulfur dioxide, or sulfur. The traditional treatment method of this method is to build a thermal cracking device, use natural gas (or fuel oil) to burn heat in a cracking furnace, and use waste sulfuric acid to make it. Although this technology is mature, it has the problem of large investment and high cost.
The organic carbon decarbonization method in waste sulfuric acid is to use solvent to extract organic substances or strong oxidants to oxidize, separate or convert the organic substances in the waste acid so that the waste acid is refreshed and reused. Although this technology is feasible, because of the higher cost, it has not yet formed a large-scale industrial production.