Enhanced H2 gas production from steam gasification of a winery waste through CO2 capture by waste concrete fines and use of alkali catalysts

This study focused on production of a high yield of hydrogen as a clean energy source from a winery waste, through steam gasification. The experiments were conducted in a fixed bed system and a thermal analysis-mass spectrometer unit. Quarry dust waste from cement industry was used to capture carbon dioxide emissions and alkali carbonates of K, Li and Na were used as catalysts. Based on the optimum conditions derived in a previous work, the effects of sorbent/biomass ratio, catalyst loading and temperature on conversion, gas composition and quality, cold gas efficiency and yield of high purity hydrogen were investigated. The amount of carbon dioxide captured up to 700 °C was 92–97 % and at 750 °C about 83 %. At Ca/C = 1 the molar fraction of hydrogen in the product gas was 74.8 %. Sodium carbonate exhibited a better overall catalytic activity at a loading of 20 % wt. In this case, hydrogen yield and concentration were 4.7 m3/kgchar and 95.9 %, respectively and char conversion 98.1 % on a dry ash-free basis. The proposed method was proved advantageous for high purity hydrogen gas production and environmental management of wastes.