Water saving potential of coal-to-synthetic natural gas

High water consumption is confining the development of coal chemical industry in China. This work analyzed the details of water consumption and water-saving potential for coal-to-synthetic natural gas process. Results show that combined heat and power plant, shift, air separation and clean-up respectively take 23.4%, 21.9%, 18.8% and 14.4% of total water consumption in the production process. And 75% of water consumption is caused by the water loss in recirculating cooling water stations, around 90% of which is due to evaporation in the case analyzed. Thus, adopting combined dry and wet recirculating cooling water system can reduce 60% of water consumption in recirculating cooling water station. Cooling water distribution has been investigated as well, which will affect the amount of water withdrawal of the whole system. By upgrading recirculating cooling water technology, water consumption can be reduced to 3.50-4.93 t/kNm(3) natural gas for coal-to-synthetic natural gas process. Besides, by taking water saving gasification technology, zero liquid discharge, integrating the water networks and improving other units, water consumption can be reduced to be lower than 3.50 t/kNm(3) . (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

High water consumption is hindering the development of the coal chemical industry in China. Research shows that upgrading cooling water technology and adopting water-saving gasification methods can significantly reduce water consumption in the coal-to-synthetic natural gas process. By integrating water networks and improving other units, water consumption can be further reduced to levels lower than 3.50 t/kNm(3).