KR20100053495A - Slurry transfer by freshwater and recirculation system for utilization of ashes from coal firing plant - Google Patents

Abstract

PURPOSE: A system for transferring slurry using the fresh water and recycling water to utilize fly ash which is exhausted in coal combustion is provided to minimize the use of industrial water, collect fly ash from an ash pond, and use the fly ash as aggregate. CONSTITUTION: A system for transferring slurry using the fresh water and recycling water to utilize fly ash which is exhausted in coal combustion is constituted as follows. Bottom ash and fly ash which have different constituent particles are separated. The slurry using the fresh water is transferred to an ash pond. Leachate is filtered, neutralized within PH 7~9 range, and recirculated.

Description

Slurry Transfer by Freshwater and Recirculation System for Utilization of Ashes from Coal Firing Plant}

The present invention separates the ash ash and fly ash slurry into the ash ash and fly ash slurry by using fresh water, not seawater, in a power plant or a wet process such as a steelmaking or smelting plant where coal ash is discharged. It is a method to easily take out coal ash without separate sorting process or desalination process in the treatment plant. It is a process to use.

Coal ash discharged from power plants, steelmaking, and smelters using coal's combustion heat is classified into bottom ash falling to the bottom of the combustion boiler and fly ash, which is mixed in the exhaust gas and collected by a coal cutter, an air preheater, and an electrostatic precipitator. Although some of them are extracted and recycled in a dry state, a significant amount of coal ash is deposited and reclaimed by transporting slurry using seawater to the treatment plant, which requires a large treatment plant. It is not suitable to use as general aggregate because it requires a lot of cost.

Industrial water supplied to power plants, steelworks, and smelters is used only as supplemental water. Slurry is generated by recycling the drainage of rainwater pipes, effluents from in-house wastewater purification facilities, and filtration of slurry leachate in the ash treatment plant and recycling the neutralized water in proper pH according to the neutralization process. When used for the transfer and transport, as well as the reduction of industrial water, and to minimize the emission of pollutants can be operated as an environmentally friendly facility.

There is no corresponding information.

There is no corresponding information.

When the slurry of bottom ash and fly ash using seawater is sent to the ash processing plant, it can be seen that it is uneconomical because a large landfill ash processing plant has to be constructed and the salt removal equipment must be added when the ash is reused. In the present invention, the wastewater purification facility effluent and rainwater pipe drainage and leachate leaching filtration. The recycled neutralized water is used for coal ash slurry generation and transport, so coal ash is easily collected and recycled in the ash processing plant while minimizing the use of industrial water. It is the process that made it possible.

In the wet ashing method, fresh water, not seawater, is used to generate and transport slurry, and the industrial water supplied from outside is limited to supplemental water. Recirculate the neutralized water and use it as water.

In general, the bottom ash particles passed through the grinder are 10-20 mm in size and are much larger than fly ash, so they are sent to the ash processing plant using a separate slurry pump and transfer pipe so as not to mix in the ash processing plant. Bulkheads are to be provided so as not to mix with non-recyclable slurries, but the leachate discharged from both slurries is combined to pass through filtration and neutralization facilities.

The tank to block external air intake at the bottom of the boiler is filled with industrial or recycled water, not sea water, to prevent salt from mixing in bottom ash.

The discharge water and rainwater pipe drainage of the facility's wastewater purification facility are collected in a separate pond to use and recycle the pump. An overflow weir, which can be discharged to the sea when a large amount of rainwater enters during the rainy season or rainy season, is installed.

 Leachate discharged from the low ash slurry and ash ash of the treatment plant is collected in one place, and after filtration, it is neutralized to the pH range of 7-9 and collected in a separate reservoir to be recycled to the pump. In this case, install overflow weir to discharge to the sea.

The low ash and fly ash produced after burning coal in power plants, steel and smelters can be recycled into aggregates, not just landfills, and the size of ash treatment plants can be reduced. It is used for slurry generation and transport by recycling filtration and neutralized water in coal, so it is easy to utilize coal ash aggregates and minimize the expected generation of pollution in the plant, so it can be operated as an environmentally friendly process.

[1] shows the use of fresh water to reduce the use of industrial water because it is easy to take out the coal ash to be used for the aggregate in the ash processing plant and recycled various effluents, filtration and neutralized water by using fresh water. It shows an eco-friendly process that can minimize the generation of waste water.

In the case of steel and smelters, large coal-fired power plants use coal to burn in a furnace and use high temperature and high pressure steam using the heat to turn turbines and generators to produce electricity or to use steam in processes that require large amounts of coal ash. It is regarded as one of the important facilities that these treatment processes must be equipped with.

Coal ash is generally classified into bottom ash falling to the bottom of the boiler and fly ash which is collected as fine particles in an air preheater or electrostatic precipitator, which are often taken out and used in a dry state. There is a limit to the continuous treatment of coal ash, and in the case of coal-fired power plants, steelworks, and smelters, it is necessary to have a process for slurrying these ashes into slurry and transferring them to a separate ash processing plant.

About 10 ~ 20% of the coal used is discharged to low ash and non-circle, and most of them produce slurry using sea water and then transfer to ash processing plant.In order to utilize coal ash for aggregate, it is necessary to remove salt. In addition, there is a limit to its use because it must have a process to classify it into the low and the non-hoe.

Therefore, the present invention uses freshwater, not seawater, to collect and aggregate as salt without removing the salt and ashing process in ash processing plant. The large amount of water required for this process is designed to minimize the use of industrial water because the large amount of water required for this is recycled by effluent from the treatment plant and neutralized water. will be.

As a result, the transfer of coal ash using fresh water rather than seawater not only facilitates the collection of coal ash, which can be recycled as aggregate, but also reduces the amount of wastewater generated in the site while reducing the use of industrial water and various pollutions emitted to the sea. The material can be eliminated and operated in an environmentally friendly process.

Coal ash, which can be used as aggregate in most coal-fired power plants, or in steel and smelters, which process wet coal, is converted to a process that can reduce the use of industrial water and minimize the generation of wastewater. .

Claims (2)

A method of producing and transporting coal ash slurry using fresh water while minimizing the use of industrial water by circulating effluent from the wastewater purification facility and rainwater pipe drainage and leachate leachate without neutralizing seawater. The slurry transported by the process according to [Claim 1] is separated for fly ash and bottom ash, and is sent to a low ash fly ash treatment plant using a separation wall through a separate transfer pipe to be salted or sorted after precipitation. How to facilitate coal ash harvesting without.

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