The economics of renewable CaC2 and C2H2 production from biomass and CaO

Abstract This article presents the economics of a bio-based CaC 2 /C 2 H 2 production concept plant. The aim of the research was to study if renewable CaC 2 /C 2 H 2 production could be competitive in comparison with current technologies. The starting point was to integrate a wood char production unit into a combined heat and power (CHP) plant with a bubbling fluidized bed (BFB) boiler. The wood char was reacted with CaO in an electric arc furnace (EAF). The production costs of the CaC 2 were determined based on the wood char production costs as well as the EAF electric power consumption. The results showed that the C 2 H 2 yield (18%) is similar to the current fossil-based production. However, the production costs proved to be even higher than the current selling prices of CaC 2 and C 2 H 2 . With the chosen basic feedstock (20 €/MWh) and electricity prices (45 €/MWh) the production costs of CaC 2 were calculated to be 725 €/t and for C 2 H 2 1805 €/t. The cost effectiveness of the concept plant was determined using the payback time method including the time value of money. The break even selling prices were 747–920 €/t for the CaC 2 and 1940–3015 €/t for C 2 H 2 depending on the desired payback time (4–30 years). The key factors in the production costs of CaC 2 and C 2 H 2 are the price of electricity and the electrical efficiency of the EAF. The results also showed that recycling the Ca at the site could save up to 48% in fresh Ca material costs.