Urgent issue----Sulfur acid production
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I would like to ask you all, what impact does the ash content in sulfur have on sulfuric acid production? Thank you, thank you. For example, the ash content is greater than or equal to 0.2% but the purity is still above 99.5%.
Due to the differences in sulfur raw materials and sulfur production processes, as well as the different storage and transportation methods of sulfur, some impurities are often mixed into the sulfur. Common impurities are generally divided into two categories. One category is soluble impurities, such as organic hydrocarbons, arsenic, selenium, tellurium, etc. Commercially, the hydrocarbon compounds contained in sulfur are converted into carbon. Sulfur containing less than 0.08% carbon is called "bright sulfur". Sulfur containing 0.4% to 0.9% carbon is called "black sulfur". Since the impurities are soluble, it is difficult to refine sulfur. The other type is insoluble impurities, such as soil, sand, ash, pyrite, phosphate rock and other insoluble impurities. Generally speaking, it is relatively easy to remove such impurities from sulfur. When sulfur is mixed with various impurities, the quality of various products using sulfur as raw material will decrease. For the production of sulfuric acid, the hydrocarbons will be converted into carbon dioxide and water in the sulfur burning, which has no harm to the sulfuric acid production process. ； If the hydrocarbon content is high (1%~3%) and the normal oxygen-sulfur ratio of the gas is endangered, the sulfur dioxide conversion rate will be reduced. Therefore, according to the impurity content and characteristics of solid sulfur, the sulfur must be refined before burning sulfur in acid production. There are generally five methods for sulfur refining.: Sedimentation method, filtration method, activated clay adsorption method, sulfuric acid method and high temperature oxidation method.
Thank you :) :handshake
Most domestic sulfur acid-making enterprises use solid sulfur, which contains high levels of impurities such as free acid, organic matter, and ash. The method of gravity sedimentation of liquid sulfur during molten sulfur cannot guarantee the quality of refined sulfur, resulting in increased system resistance, frequent shutdowns and maintenance, and affecting the start-up rate. Liquid sulfur filtration method should be adopted, and a pressurized leaf-type liquid sulfur filter should be used to ensure that the molten liquid sulfur is neutral, w (S) > 99.9%, w (organic matter)
Excessive ash content will reduce the conversion rate. Since the sulfur acid production unit does not have a furnace gas purification system, it should be removed before sulfur is burned. In China, liquid sulfur filtration is generally used, using a pressurized leaf-type liquid sulfur filter.
The ash in the sulfur and the impurities brought in during the transportation process are generally removed by natural sedimentation in the sulfur melting system. The liquid sulfur can generally be removed by ensuring that the residence time of the liquid sulfur in the refined sulfur process is 200 hours. Samples are taken in the refined sulfur pool to determine whether filtration is required. There are many ways to filter, you can check the relevant information. The fly ash from sulfur combustion can be removed through the hot filter before the converter after the sulfur furnace, and the hot filter is cleaned once a year.
The main disadvantages of high sulfur ash content: 1. Increase the difficulty and consumption of liquid sulfur refining ； 2. The ash will eventually accumulate in the upper part of the section, increasing the bed resistance and increasing the screening frequency. ； 3. Ash will absorb the active ingredients in the catalyst and accelerate the decline of the catalyst activity. 4. Ask experts to supplement……
Ash should be the residue left after sulfur combustion that cannot be turned into gas. It may be in the form of small molten particles at high temperatures. Such small particles will solidify when encountering low temperatures. Therefore, when the high-temperature flue gas enters the fire tube boiler, the small molten particles cool down, accumulate, and scale at the pipe mouth (corundum casing), which reduces the flow section of the waste heat boiler and increases the flue gas resistance. The higher the ash content, the faster the resistance rises. Due to the hard scale, it is difficult to clean and the casing is easily damaged. This post was last edited by zpqing on 2008-3-20 13:25 ]