(426f) Sustainable Integration of Refineries and Biorefineries with Forest Plantations to Reduce Emissions

Fossil fuel production typically generates large amounts of greenhouse gas emissions, which are associated to the global warming problem. It is important to note that small increments in the global temperature involve drastic consequences in the world population. For this reason, some authors have stated that it is necessary to limit the greenhouse gas emissions from human activities. Furthermore, several authors have suggested alternatives to address this problem. For instance, biomass has been identified as a high potential renewable energy source for production of biofuels, chemicals and other products using several processing technologies. However, to consider the large scale production of biofuels from biomass, the entire supply chain must be analysed from the economic, environmental and social points of view. It is worth noting that the most of the papers published in the literature present several alternatives for the reduction of the overall environmental impacts during the energy production; however, did not consider a scheme to integrate two or more ways to reduce the global emissions in the supply chain. Therefore, this paper presents a mathematical programming model for the optimal planning for the production of fuels through refineries and biorefineries integrated with the forest plantations focused on decreasing the total greenhouse gas emissions, maximizing the net profit of the system and maximizing the generation of jobs simultaneously. This way, the proposed approach takes into account two ways for the reduction of greenhouse gas emissions, which is given by the production of biofuels in the biorefineries and the forest plantations to capture the CO₂. Additionally, the present approach considers several important issues such as the location of facilities, availability of raw materials, demand of products, inventory of the greenhouse gas emission, as well as the generated jobs for the different activities involved in the supply chain. It is important to mention that the problem is defined by a set of possible oil reservoirs distributed for the extraction of oil to be sent to refineries. Also, the supply chain includes a set of possible harvesting sites to produce different raw materials to be sent to biorefineries. In addition, there is the possibility to produce fuels from oil in the existing refineries, as well as installing necessary refineries to satisfy the fuel demand. On the other hand, it considers the possibility to install new biorefineries to produce biofuels and the option to use existing biorefineries. Furthermore, the proposed model incorporates pollution trading concepts to reduce emissions through a set of forest plantations with different capacities and sizes. It should be noted that the fuel demand, which can be satisfied via fossil fuels or biofuels, is received from several distribution centers. Therefore, the problem consists in determining the topology of the supply chain, the flowrates of products and raw materials, capacities of the refineries, biorefineries and forest plantations in order to obtain the best environmental, social and economic benefits.

The model is formulated as a mixed integer linear programming problem, which involves three objective functions in order to perform the sustainable planning of the production process of fuels in Mexico considering reduction of greenhouse gas emissions, mainly CO₂. In general way, the proposed mathematical formulation is composed of constraints for mass balances, capacity limitations, distribution, carbon emissions and capture as well as objective function equations. The economic objective function considers the maximization of the total profit, which is the sum of the profit from refineries, biorefineries and forest plantations. The profit of refineries and biorefineries includes the revenue from the sale of products, and all the involved costs such as the cost of raw materials for refineries and biorefineries, the operating costs, the capital costs for implementation of new refineries and biorefineries, the transportation costs for raw materials from harvesting places to processing plants, and the transportation costs for products. It also considers a cost for the emissions; for instance, the refineries should pay the forest plantations to reduce their emissions. In case of forest plantations, the profit considers the revenue for the payment that refineries or biorefineries have for their emissions minus the costs of their implementation. The environmental objective is to minimize the total CO₂ emissions, which considers the sum of total emissions from refineries and biorefineries minus the emissions captured by the forest plantations. The total CO₂ emissions from refineries include the ones produced in all the involved activities, including oil extraction, oil refining, transportation of products as well as the emissions obtained from burning petroleum fuels. Whereas the emissions of the biorefineries include the emissions for each of the activities involved in biorefineries such as emissions of CO₂ for biomass transportation, production in biorefineries, emissions produced by the transportation of bioproducts from biorefineries to distribution centers, emissions for the use of bioproducts and the captured emissions of CO₂ by the biomass growth. Furthermore, the captured CO₂ emissions by the eco-industries are given by a unitary factor multiplied by the total number of trees for the forest plantations. Additionally, the model considers a social objective function, which is the maximization of the total generated jobs for the implementation of the proposed scheme. This objective function takes into account the jobs generated in refineries, biorefineries and forest plantations. The jobs of refineries include the ones for processing and installing only in the new refineries, it is important to note that the transportation jobs are not considered because they are given in the transportation network for the existing refineries. On the other hand, the jobs of biorefineries include the ones for biomass plantations, biomass transportation, installing and processing of new biorefineries. With respect to the forest plantations, the considered jobs correspond to the needed people to take care of the plantations.

The results have shown that the relationship between the environmental and the social objectives is inversely proportional, while the behaviour of the economic objective with respect to the environmental objective is different. Also, the results illustrate that petroleum refineries are more economically attractive than the biorefineries, although the biorefineries can satisfy the fuel demand with a minor environmental cost. Additionally, based on the results, it is possible to conclude that the forest plantations can be important sinks for the CO₂ emissions from the fuel production process, which can be afforded by the refineries.