Inclusivity is a vital aspect of sustainable development which has been emerging as a challenge in economically developed, matured societies. In Japan, the rural areas are suffering from lagged economic development, the aging society, and declining population. Tackling sustainability challenges without leaving out problems in these areas are essential, but requires a new approach in industrial development. Creating sufficiently productive and profitable systems that utilize locally-available resources are seen as a potential key to vitalize the rural areas while tackling the SGDs.
Attempts to collect and study all the relevant information can lead to an excessive requirement on time and effort in the early stages of a design project. Because some of the unknowns are more important than others, prioritization of the unknown factors that requires a closer investigation can potentially reduce the time and cost for the initial design. In this study, a system synthesis method that generates combinations of resources, technology, and products, ranked in order, formulated as a MILP is applied to indirectly prioritize the unknowns, while comprehensively exploring the combinations of the known options.
The higher ranked systems will include some designs that are impractical due to missing practical constraints. The ranked list of the systems will help to identify overlooked constraints, starting from more important ones. The unknowns that are related to the identified constraints are then studied and added in the systems synthesis model. After several iterations, all the critical unknowns are studied to describe the key constraints and the most promising systems can be proposed.
Features added to existing studies, i.e., 1) consideration of the combinations at its suboptimal capacity of processing, 2) incorporation of material storage equipment and efficiency in order to overcome the seasonal variations in availability of resources and the demand of products, will be introduced with simple examples.
Methyltetrahydrofuran (MTHF) have received great attention for combustion system applications, because it can be readily used in blends with gasoline and diesel without major engine modifications. In this study, as a sustainable platform chemical for the biofuels and biochemicals, conversion of MTHF from lignocellulosic biomass was studied. For the conversion of MTHF, domestic grown woody biomass such as pine and oak in Korea were firstly treated by chemical and thermal treatment for the production of C6 substrate and further production of levulinic acid (LA) via 5-hydroxymethylfurfural (HMF) intermediate, which was then subjected to the catalytic conversion for the conversion of MTHF.
At the beginning of the conversion process, alkaline reagents (ex. sodium hydroxide and ammonium hydroxide) were applied to produce C6-rich substrate (>70%), which was then converted by de-hydration and re-hydration reactions into LA using sulfuric acid (1~5 wt%) at high temperature (121~190 °C). For the conversion of MTHF via gamma-valero lactone (GVL) intermediate using de-hydration and hydrogenation reactions under high temperature and pressure conditions, high-efficiency heterogeneous bimetal catalyst was synthesized and attempted for precious metal replacement in the presence of the effective CTH (catalytic transfer hydrogenation) solutions.
In this paper, conversion yields of C6, LA, and MTHF were evaluated and reported under various reaction conditions. For the increased MTHF production, various catalytic reaction conditions pertinent to effective and viable process were explored and discussed.
A continuous twin screw-driven reactor (CTSR) can provide a unique and efficient reaction environment for the pretreatment of lignocellulosic biomass. CTSR has the ability to provide high shear, rapid heat transfer, effective mixing. The thermo-mechanical energy provided by the continuously stirred screws in CTSR, which causes the shear forces, can be applied to the continuous pulverization of biomass, thus improving the overall rate of biomass conversion. Considering the high labor intensity and energy requirement of batch pretreatment, a CTSR process has great potential for increasing the efficiency of biomass pretreatment.
CTSR for the pretreatment of biomass would be practicable and useful for large scale production because it affords high-efficiency pulverization by a high shearing force, and adaptability to many different process modifications, such as application of simultaneous physical and chemical treatments using other catalysts. The performance of biomass pretreatment through CTSR is a complex function of screw rotational speed, throughput, and screw configuration etc. The interaction between different processing parameters leads to complex functions of shear conditions and reaction severities, both of which affect pretreatment performance.
With the aim to provide a further insight into CTSR pretreatment, enlarged CTSR to 100 kg/day scaled was developed and demonstrated. Mathematical modelling for fluid dynamics and heat transfer were developed by a set of ordinary differential equations (ODE) based on first-principle models. The resulting ODE set was experimentally validated using model biomass (sawdust) as feedstock. The kinetic parameters of biomass pretreatment performance were estimated from experimental results.
These results will contribute to improved reactor design and scale-up tasks, and in turn, to the successful deployment of novel industrial-scale technologies for biomass pretreatment.
Industrial symbiosis with unused local biomass can be one of a key approach from the viewpoint of sustainability of agriculture, forestry and the regions. Planning biomass-based industrial symbiosis necessitates hard decisions including long-term visioning of the regions and consensus building among various stakeholders such as agriculture, forestry, energy supplier, local government, and technology researchers. Chemical engineering approach with modeling and simulation can strongly support such planning process. The planning process of the symbiosis to be supported has not been well established nor systematized in previous studies. In this study, systematic planning process for biomass-based industrial symbiosis was proposed and the requirements of its supporting mechanisms were defined. The planning process was structured as the series of sub-activities based on the re-analysis of the case studies for planning industrial symbiosis integrating cane sugar industry and local forestry on a specific region. Modeling and simulation of regional energy systems with multiple co-generation plants fueled by local biomass from the industries were performed in the case studies. The planning process was defined that consists of the activities of planning tasks, i.e., <Examine present system>, <Generate alternatives>, <Simulate flows> and <Evaluate>. Additionally, these tasks are controlled by <Manage>, and the proposal of the symbiosis plan as the product by the tasks are checked by <Review>. These activities of planning tasks can be supported by the mechanisms, such as IoT monitoring system, technology matching tool, flow simulator and evaluation tool. The applicability of the planning process and the supporting mechanisms is to be discussed through new case studies in other regions. Human networks among region, academia and industries have significant roles to implement the symbiosis plans toward the regional sustainable visions even if the supporting tools highly developed in future.
To effectively mobilize the limited time and resources for the accomplishment of a transition towards sustainability, efforts on a technology development must be made in a manner coherent with other efforts under a vision on the sustainable society. Technology Roadmapping (TR) is amongst the several approaches that may cross-link a technology development with a future vision. Here, I provide an example of assisting TR by exploring the balances between technology performances with other exogenous variables in the future society with a dynamic Material Flow Analysis (dMFA).
In Japan, a future target of the power supply configuration (energy mix) based on the massive introduction of renewable energy has been advocated, in which Photovoltaics (PV) accounts for ~7% of the total power generation capacity, i.e., approximately 30% of the renewable power sources. On the other hand, a substantial amount of Si type PV (Si-PV) would reach their End of Life (EoL) soon. Therefore, the development of a technology recovering Si from EoL Si-PV may effectively respond to the demand to achieve the target without spending a massive amount of energy for Si purification from Silica sand. To consider such technology, a long-term evaluation of benefits and impacts on both economy and environment is required to invite stakeholders to jointly materialize the reasonable and comprehensive roadmap. Here, our team conducted a time series quantification of flows and stocks in an envisioned Si-circulation system. Then, we deduce the development directions as a roadmap with respect to various design variables (ex. an average lifetime of product) on the basis of multiple criteria (e.g., the net-energy acquisition and net-CO2 avoidance). With this example, I aim to highlight the potentials and challenges of vision-oriented technology development for the achievement of SDGs 9: Industry, Innovations and Infrastructure and SDGs 7: Affordable and Clean Energy.