Japan efficiently reuses over 99% thermal coal ash

This is one of the highlights from the 2nd Japan – Viet Nam Coal Energy Working Group Conference, held in Hanoi in two days of 8 – 9 November 2018, jointly organized by Viet Nam Electricity (EVN) and Japan Coal Energy Center (JCOAL).

According to JCOAL, in Japan, thermal coal ash since its allowed commercialization in the early 1950s has quickly and widely used.

In 2016, thermal coal ash output of the country was about 12.35 million tons and its useful amount was 12.35 million tons, equivalent to 99.3%. It is one of the countries with the highest rate in use of thermal coal ash in the world.

Particularly, coal ash is mainly used as cement raw material, cement mixing additive, concrete regulating additive. In which, only the coal ash output used as raw material for cement accounts for about 68% of the total ash in Japan.

Additionally, thermal coal ash is also used in the field of construction engineering (as road pavement materials, ground-leveling materials, etc.) or applied in the field of agriculture, forestry and fishery (as fertilizer, land reclamation, artificial sand yards, artificial texture to form water streams, etc.).

2nd Japan-Vietnam Coal Energy Working Group Conference

Sharing information at the Conference, representatives of EVN said that currently, the volume of ash, slag discharged from its coal-fired thermal plants of EVN was about 8.1 million tons per year. In which, at coal-fired thermal power plants in the North, the situation of ash and slag consumption was relatively proper. Most of the plants have signed contracts with their counterparts.

In the South, thermal power plants such as Duyen Hai 1, Duyen Hai 3, Vinh Tan 2, etc., despite signed contracts with partners to purchase all the ash, their consumed amount is not large. The reason is that people in the South haven’t had habit of using construction materials from ash, slag. At the same time, plants are far from the market, leading to high freight rates, which reduces their competitiveness compared to traditional construction materials.

Ash, slag from EVN's thermal power plants are common industrial solid waste, allowed to reuse for construction purposes. For ash, slag of domestic coal, it needs to be refined for reducing carbon content to below 6% to be used as cement additive.

Presently, EVN has proactively prepared for a dossier for the disposal of ash, slag from thermal power plants in the long term, with the target of selecting partners who are capable, have feasible solutions and ready to cooperate with power plants to consume ash and slag in a long time.

Tank truck purchasing fly ash at Nghi Son 1 Thermal Power Plant

Discussing at the Conference, the JCOAL representative said that in order to increase the usefulness of the ash, coal slag consumption in Vietnam, it is necessary to gain support from the State to develop a legal framework on standards and consumption of coal ash. At the same time, directing and encouraging industries to use coal ash (for example, the cement industry) and related units to agree on increasing consumption of this material source.

JCOAL also advised EVN to apply solutions of improving boiler operation, adjusting fire mode and re-burning ash, etc., to reduce the content of carbon not totally burned in coal ash to lower rate (reference level of JPOWER is about 5%), being suitable for cement mixing additive.

At the Conference, the parties also discussed on other topics such as SOx deoxidizing methods at thermal power plants; import of coal and method of mixing coal, etc.

This is the second Conference held in 2018 by the Japan - Vietnam Coal Energy Working Group. At the previous conference, the Working Group discussed on high-performance and environmental protection technologies for thermal power plants.

  • 10/11/2018 10:06
  • evn.com.vn