Case study on the successful production of food grade of CO2 from biogas

Food production, preservation, distribution and organic food waste deposal, consume a considerable amount of energy and contribute to the total CO2 emission [1]. This associated to the use of traditional fossil fuel energies are the main cause of environmental pollution, greenhouse gas emissions and global warming. In this contest it's necessary to reduce the CO2 emission, making the food chain more sustainable trough the use of renewable energy. The biogas obtained from the anaerobic digestion of biomass based on the organic wastes of food is one of the most promising alternative energy. The biogas upgrading still produces the greenhouse gas CO2 as waste product. This work presents a case study, aimed at biogas upgrading with simultaneous purification of methane, CO2 and concomitant re-use of CO2 in the food industry. The objective was to evaluate the feasibility of biogas upgrading to distribution grid quality methane, via different purification steps, including CO2/CH4 separation by polymeric membranes. The innovative aspect is the further purification of CO2 from a useless by-product to a food-grade quality gas for commercial application in the food and beverage industry. The chemical purity of gas streams was compared with the guidelines of the European Industrial Gases Association and the International Society of Beverage Technologists (EIGA /ISBT) for CO2 used in the food industry. The microbiological purity was compared with the limit values defined in the European Collaborative Action [3,4]. The chemical and microbiological analysis of CO2 was proved to be suitable for food-grade applications. References: 1. I.E. Grossmann, Comput. Chem. Eng. 29 (2004) 29-39 2. P. Roy, J. Food Eng. 90 (2009) 1-10 3. P. Carrer et al., Science of the total environment, 270 (2001) 1-3. 4.EIGA_Spezifikationen