Lignite-to-coke technology

With economic growth, environmental protection is receiving more and more attention, particularly in coal-rich, water-short, environmentally fragile Inner Mongolia and northwestern China where environmental requirements are stricter. Given that the traditional wet desulfurization process is restricted by its large land occupation and high dependence on water resource, the dry flue gas purification technology featuring small land occupation, water efficiency and environmental protection becomes more promising. Countries are actively involved in research of dry desulfurization technology and moving it toward equipment scale-up, system simplification and control automation. SPC has developed the lignite-to-AC technology in order to promote the application of the dry flue gas desulfurization and integrated purification technology, cut its operating cost, create specialist, large-scale production advantage and sharpen SPC's competitive edge in the area of dry flue gas desulfurization and integrated purification.

I. Advantages of lignite-to-coke process

(1) With high volatile components, lignite is favorable to creation of porous adsorbent.

(2) With high oxygen content and low hydrogen content, lignite is favorable to formation of pore structure and increase in alkaline content.

(3) With low degree of coalification and high reactivity, lignite is helpful to formation of pore structure for catalyst sedimentation.

(4) Lignite is inexpensive as raw material for preparing AC.

(5) Lignite is readily available at low costs.

II. Lignite-to-AC process flow

Lignite upgrading: high-moisture lignite with moderate ash content is subjected to thermal drying or low temperature carbonization to remove the majority of moisture and some volatile components from the lignite, obtaining upgraded coal for later use.