Method and device for performing flue gas desulfurization by using ammonia process

Abstract

The invention provides a device for performing flue gas desulfurization by using an ammonia process. The device comprises two units, wherein a first unit which is provided with a desulfurization unit having a desulfurization tower is arranged for absorbing primary flue gas so as to de-sulfur; a second unit is an ammonium sulfate made unit formed by a vacuum crystallizer; the upstream of the vacuum crystallizer is communicated with a circulating serous fluid outlet of the desulfurization tower; a chilling de-dusting tower is arranged on the upstream of the desulfurization tower so as to chill and remove dust from the primary flue gas and then de-sulfur in the desulfurization tower; and the bottom of the desulfurization tower is provided with a circulating serous fluid pool. The device for performing flue gas desulfurization by using an ammonia process of the invention can overcome the various shortcomings in the current flue gas desulfurization process by using the ammonia process, can reliably and continuously run, can decrease energy consumption, has no secondary pollution and can manufacture the high-quality desulfurization products.

Description

technical field [0001] The invention relates to a flue gas desulfurization method and its equipment, in particular to an ammonia flue gas desulfurization method and its equipment. Background technique [0002] The existing domestic coal-fired boiler flue gas ammonia water scrubbers mainly include packed absorption towers and spray empty towers. This type of absorption tower is currently used more in China and is also a relatively mature ammonia desulfurization absorption tower device. [0003] However, there are some problems in the application of the current ammonia desulfurization device. The ammonia desulfurization process using the packed tower is prone to clogging, and the ammonia desulfurization process using the spray tower is poor, mainly due to the aerosol acid mist at the outlet of the absorption tower. serious. [0004] In addition, as far as the ammonia desulfurization process is concerned, there are two main problems: one is to use the waste heat of the flue ga...

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Problems solved by technology

[0003] However, there are some problems in the application of the current ammonia desulfurization device. The ammonia desulfurization process using the packed tower is prone to clogging, and the ammonia desulfurization process using the spray tower is poor, mainly due to the aerosol acid mist at the outlet of the absorption tower. serious

[0004] In addition, as far as the ammonia desulfurization process is concerned, there are two main problems: one is to use the waste heat of the flue gas to concentrate the ammonium sulfate in the circulating slurry in the absorption tower to make it reach a supersaturated state, thereby separating out ammonium sulfate crystals. In the application of this process, the ammonium sulfate slurry will be mixed with a large amount of impurities during the crystallization process

The second is to use boiler waste heat steam to evaporate and concentrate ammonium sulfate slurry. The quality of ammonium sulfate crystal particles obtained by this process is high, but it needs to consume a lot of steam and the operating cost is high.

Although this process can save the crystallization steam consumption, due to the supersaturated local crystallization in the tower, the crystallization time is short, so the crystallization degree of ammonium sulfate is very poor, and at the same time, the possibility of blockage of the absorption tower is increased, and the absorption tower is enlarged. Exported aerosols

[0006] If a spray tower is used, since the absorption tower is an empty tower for spraying, the possibility of clogging is reduced, and the ammonium sulfate slurry is concentrated in the tower to precipitate ammonium sulfate crystals. This process can also save crystallization steam consumption, but Due to the supersaturated local crystallization in the tower, the crystallization time is short, so the crystallization degree of ammonium sulfate is very poor. At the same time, the spray tower will produce a large amount of ammonium sulfate aerosol during the spraying process, which is difficult to remove by the general demister, resulting in the absorption tower Severe white smoke at the exit

[0007] There is also ammonia desulfurization using the dynamic wave process of smelting tail gas treatment. The main performance is in Shijiazhuang Refining and Chemical Industry. This technology can remove flue gas with high temperature, extremely high dust content and extremely high sulfur content, but the process equipment There are many, but there are also the disadvantages of large system resistance, small amount of flue gas treatment, low oxidation rate, and large aerosol emissions

[0008] All three processes have impurities in the flue gas that will be mixed into the ammonium sulfate slurry, resulting in lower quality of the final ammonium sulfate product

[0009] Due to the shortcomings of the ammonia-based flue gas desulfurization process and devices, there is an urgent need for an ammonia-based flue gas desulfurization process that can ensure continuous and stable operation, and can solve the problem of outlet flue gas in the existing ammonia-based flue gas desulfurization. There are a series of problems such as aerosol, by-product ammonium sulfate crystallization, high energy consumption, low product quality and unstable desulfurization absorption tower equipment

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