What is the purpose of ash flushing in power plants?
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What is ash flushing in power plants? What are the characteristics of ash flushing water, and what is its required amount?
Power plant ash flushing involves using water to wash the fly ash collected by dust collectors, etc., in order to prevent further air pollution. Flue wash water contains high levels of suspended solids and total hardness; generally, the sulfate ion concentration is also high. If the coal has a high sulfur content, then the sulfate ion level in the flue wash water is high as well. Such water tends to cause scaling and can easily block pipes.
Power plant ash flushing involves using water to wash the slag from coal-fired power plants as well as the fly ash collected by dust collectors, in order to prevent further air pollution. Since fly ash generally contains alkaline substances such as active calcium oxide, the water used for washing the fly ash usually has a high pH value, a high concentration of calcium ions, very high total hardness, as well as high levels of suspended solids.
The source of this information is Interactive Encyclopedia. Gray water refers to the water used for washing ash in power plants. A large amount of fly ash must be transported from power plants to ash storage sites. Using a hydraulic ash removal system to convey the ash and slag to these sites is a cost-effective method, and it is also the primary way of handling ash in China at present. After the ash and slag mixture is sent to the storage site via pipelines, the coarse impurities in it settle there, while the clarified water can be discharged directly into water bodies or sent back to the power plant for reuse. Currently, most power plants store fly ash in ash ponds, which generates a large amount of ash washing water. However, the quality of the ash flushing water changed significantly; parameters such as pH and SS exceeded the **specified discharge standards, making ash flushing water the biggest source of water pollution in coal-fired power plants. To protect the environment, it is now **regulated that ash and slag must not be discharged into rivers; they must be utilized in various ways or stored in ash dumps. Since the ash wash water is alkaline, if left untreated and discharged directly, it not only pollutes water bodies but also forces coal-fired power plants to pay fees for pollution discharge and exceeding regulatory limits. Therefore, ash flushing water has become a new issue in the wastewater treatment of thermal power plants.
The slag from coal-fired power plants and the fly ash collected by dust collectors generally contain alkaline substances such as active calcium oxide (FCaO). During the hydraulic transport of these residues, the dissolution of alkaline substances like FCaO leads to deterioration in the quality of the water used for washing the residues; the pH value increases, and the Ca2+ concentration rises. Additionally, these residues contain pollutants such as heavy metals, as a result of which the quality of the water discharged from the residue disposal sites exceeds the maximum allowable emission limits specified in the **Comprehensive Wastewater Discharge Standards** (GB8978 - 96). There is a paper titled \"A Brief Discussion on the Treatment of Ash Wash Water in Coal-Fired Power Plants\" that covers this topic; everyone can take a look at it. The link is as follows: http://bbs.hcbbs.com/viewthread.php?tid=413470&extra=page%3D1&frombbs=1 This post was last edited by metaled on 2009-3-12 14:17]
The desulfurization water from power plants is alkaline due to the presence of ions such as Ca and Mg, and can be used to neutralize acidic desulfurization wastewater.
The introduction on the fourth floor was very professional; I learned a lot from it.
Adding scale-inhibiting dispersants to the backwash water from power plants can improve the recycling rate.
Power plant ash flushing involves using water to wash the fly ash collected by dust collectors, etc., in order to prevent further air pollution. In my work, I have noticed that in some power plants, environmental protection measures are put in place only to meet inspection requirements, and those devices are not used very often.
When some of the ash generated by a power plant cannot be fully utilized, it can be sent to the ash dump using hydraulic flushing; ash slurry is generally alkaline, which can cause scaling in the pipes. Currently, dry ash removal is generally used in large power plants, while hydraulic ash flushing is less common – water conservation must be taken into account! ! !