Olefins are one of the most important platform chemicals. Developing coal-to-olefins (CTO) processes is regarded as one of promising alternatives to oil-to-olefins process. However

CTO suffers from high CO2 emission due to the high carbon contents of coal. In China

there is 7×1010 m3 coke-oven gas (COG) produced in coke plants annually. However

most of the hydrogen-rich COG is utilized as fuel or discharged directly into the air. Such situation is a waste of precious hydrogen resource and serious economic loss

which causes serious environmental pollution either. This paper proposes a novel co-feed process of coal and COG to olefins in which CH4 of COG reacts with CO2 in a dry methane reforming unit to reduce emissions

while the steam methane reforming unit produces H2-rich syngas. H2 of COG can adjust the H/C ratio of syngas. The analysis shows that the energy efficiency of the co-feed process increases about 10 %

while at the same time

CO2 emission is reduced by around 95 % in comparison to the conventional CTO process.