Magnesium sulfate preparation system

Abstract

The invention discloses a magnesium sulfate preparation system. The system comprises a pulping device, a flue gas oxygen content adjusting device, a desulphurization device, a supplementary oxidation device, a filtering device, an evaporating device, a cooling crystallization device and a separator. The flue gas oxygen content adjusting device is used for controlling the oxygen content of a flue gas before desulphurization in a range of 15-25vt%; and the evaporating device and the cooling crystallization device are arranged in a separate manner. The method can simultaneously realize the efficient desulphurization of the magnesium oxide flue gas and the preparation of the high-quality magnesium sulfate product, and avoids the secondary pollution problem caused by landfill treatment of gypsum which is a common wet calcium method desulphurization byproduct.

Description

technical field [0001] The invention relates to a system for producing magnesium sulfate, in particular to a system for producing magnesium sulfate by using slurry after flue gas desulfurization. Background technique [0002] The desulfurization process based on the traditional limestone gypsum method has been widely used in the desulfurization industry. Desulfurization gypsum, a by-product of desulfurization projects, is difficult to reuse and forms solid waste, causing secondary pollution to the environment. In 2012, the thermal power plants of China's five major power companies produced 60 million tons of desulfurized gypsum. How to deal with these solid wastes has become a headache for various enterprises, governments at all levels, and environmental protection agencies. The reality that China is short of sulfur but not short of gypsum (gypsum) has made most environmental protection practitioners start to think about how to develop new desulfurization technologies that a...

AI Technical Summary

Problems solved by technology

In such a low oxygen content environment, the slurry mainly contains MgSO 3 Form exists, in order to produce the by-product magnesium sulfate heptahydrate, it is necessary to set up an oxidation fan with a large flow rate and an oxidation pool with a residence time of more than 10 hours, which increases the floor space and increases the energy consumption of the device, thus causing the use of magnesium oxide The production of magnesium sulfate heptahydrate from waste liquid produced by desulfurization requires high economic cost

Patent CN102631836A "New process for recovering magnesium sulfate heptahydrate from flue gas desulfurization of magnesium oxide", in the case of no oxygen balance and adjustment device at the front end, the converted MgSO 4 The amount is small, the conversion efficiency is about 40%, and the efficiency is too low to affect its economy

In addition, the crystallization method described in this patent is "air cooling crystallization". This crystallization method cannot control the size of crystal particles, and the product quality cannot be standardized.

[0004] There are other similar methods or processes, but as described in the two patents disclosed above, there are traditional impurity removal methods such as gravity sedimentation, which require a long residence time and a large equipment volume. , which inevitably causes the process to be unable to run continuously and increases the overall footprint of the device

Moreover, the magnesium sulfate solution is not suitable for the traditional method of concentrated crystallization. This method uses the characteristics of the solubility of magnesium sulfate to decrease when the temperature exceeds 60°C. This high-temperature crystallization method needs to consume more high-quality steam and will Causes frequent blockage of the slurry delivery pipeline, making it difficult to achieve continuous and stable production of by-products

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