(687e) Production of (Bio)Butanol By Means of a Design for Sustainability Methodology

This contribution presents the design of a biobutanol production process from biomass as raw material using a biochemical conversion process. The process design is made by means of a methodology for the design for sustainability (DFS), involving five stages leading to processes that fulfill not only technical requirements but also incorporate business and sustainability criteria.

The DFS methodology was developed by integrating the tools for the design, planning and production managing comprising all the steps in the design of a business processes going from the setting up of a new product or sustainable service up to the managing of the (sustainable) production. These stages are: 1) Define, 2) Evaluate and Select, 3) Design, 4) Execute and, 5) Manage.

The stage one (Define) deals with the development of a new product or service coming from a given need previously identified, therefore, potential products/services are detected in order to have a feasibility for their commercialization. In this stage a pre-synthesis of the process is carried out, obtaining one or more technologic proposals that add value to the partitioned market, this is done by a constant evaluation of the design through tables of effect and failure modes. In this sense, there is a continuous check up with the clients in order to compare the technologic proposals with their requirements, both technical and environmental in order guarantee that the product/process adds value to all stakeholders, and here it is where the key performance indicators (KPI) arise naturally helping to measure the sustainability of the product and process. As one of the main products from this stage are the process flow diagrams (PFD), plant lay-out, pipe and instrumentation diagrams (PID), diagrams for the equipments, cost estimation of the project which is evaluated with respect to financial parameters from the investors. The fifth stage (Management) validates the elements defined of the business process against the objectives and their variability in order to start the continuous improvement (kaizen) process.

As mentioned before the production of (bio)butanol is presented as an illustration of the DFS methodology. The n-butanol is selected (Define stage) as a product due to its potential to be used as a (bio)fuel and also as a solvent, the global market of n-butanol will grow up at an annual rate of 4.72% during the 2018-2022 period. The global demand is 3.7 million tons approximately, where USA and Europe are the main exporters while China the largest buyer. In Mexico is expected that within 2014 and 2019 the annual consumption rate grows up to a 7%. It possesses an energy content closer to the gasoline than the ethane and it reaches a 95% of energy than the same volume of gasoline while the ethanol only reaches up to a 75%. The n-butanol can be blend with other fossil fuels easily and in higher proportions than the ethanol (< 10%), since it presents an air/fuel ratio closer to the gasoline and diesel and there is no need to modify the actual vehicles to be used.

The production of biobutanol is going to be addressed mainly to the (bio)fuels sector but there is also an opportunity in the petrochemicals sector; the technology by means of the (bio)butanol will be obtained is from lignocellulosic raw materials (Evaluate and Select stage). These lignocellulosic materials might come from the sugar cane, bagasse, forestry or paper industry residues, although the lignin contents vary from each source an average content is going to be taken into account as part of the detailed design. Within this stage the conceptual design of the process takes place, where in this case, the main sections are identified, this is, raw materials supply, pretreatment, hydrolysis, fermentation and product separation. Simulations are carried out with commercial process simulators such as Aspen Plus® to establish the operating conditions of the process.

The remaining three stages are going to be outlined in a broad sense since they require the actual implementation of the business process, however, it is possible to highlight the main issues to be considered on the three of them, for example what it would be necessary to measure and control (KPI) once the process is operating based on sustainability as well as on lean methodology criteria.