Understanding evolution of the products and emissions during chemical activation of furfural residue with varied potassium salts

Furfural residue is a solid waste produced in manufacturing furfural from biomass like corncob, which can be converted into liquid/gaseous fuel and activated carbon via chemical activation. In this study, in addition the pore structure of activated carbon, the impacts of varied potassium salts (KCl, KOH, K 2 CO 3 and K 2 C 2 O 4 ) on the properties of gases and bio-oil formed during activation of Furfural residue was studied. The results showed that the potassium salts suppressed cracking of condensable volatiles into gases, producing more bio-oil at expense of gases. KOH showed the highest activity for cracking, producing the lowest yield of activated carbon (4.8%) without activator with lower degree of crystallization than that K 2 CO 3 and K 2 C 2 O 4 as activators (20.1% and 26.9%). The activated carbon activated with K 2 CO 3 or K 2 C 2 O 4 showed the flaky membrane structure packed with varied layers, but not with KOH as the activator. K 2 C 2 O 4 , KOH and K 2 CO 3 as the activators could promote cracking, deoxygenation , dehydrogenation and aromatization reactions, generating abundant micropores , while KCl could not. In addition, K 2 C 2 O 4 as the activator of furfural residue showed the least energy consumption and environmental impacts, while with KCl was highest. The results herein demonstrated the potential of furfural residue as feedstock for the production of activated carbon and liquid fuels . • Potassium salts suppress cracking of volatiles into gases, forming more bio-oil. • KCl has low capability for cracking of furfural residue, generating limited pores. • Activated carbons from K 2 CO 3 and K 2 C 2 O 4 have packed membrane structure. • K 2 C 2 O 4 promote deoxygenation, dehydrogenation and aromatization in activation. • K 2 C 2 O 4 has least energy consumption and environmental pollution in activation.