Valorization of waste biomass via an integrated gasification system for the co-production of dimethyl ether and urea

Energy and chemicals such as urea have a large carbon footprint associated to greenhouse gas emissions and must be developed sustainably for the sake of society. This work presents the simulations of a system to produce Dimethyl Ether (DME) and urea from the air gasification of waste biomass coupled with carbon capture technology. The potential of different waste biomasses (avocado stone, palm tree husk and sugar cane bagasse) in the co-production of DME and urea was assessed in terms of reaction, product yields, energy and exergy efficiencies. The syngas with the largest H2/CO ratio (1.80) is produced from the gasification of avocado stone, while sugar cane bagasse results in the largest DME and urea reaction yields. In terms of energetic and exergetic analysis, it was found that most of the exergy losses occur during heat transfer with scrubbing liquids and wastewater (82 % of the losses in the waste streams), while the largest exergy destructions occur in the gasifier, methanol and ammonia synthesis units due to chemical reaction (more than 50 % of the destroyed exergy). Results indicate that in the case of Mexico, the studied biomasses can be used to synthesize DME and urea while satisfying the country's needs.