8:30am - 8:50am
Sustainable manufacturing of polymeric materials: life cycle and techno-economic analysis of soybean oil-based acrylic monomers production
Department of Coatings and Polymeric Materials, North Dakota State University, United States of America
Recently, renewable raw materials have become enormously appealing in making bio-based polymeric materials. Plant oil could be used as a bio-renewable resource in the manufacture of polymers and polymeric materials with versatile properties (toughness, hardness, flexibility, adhesion, water and solvent resistance etc). Plant oil-based acrylic monomers can be (co)polymerized with a variety of counterparts using free radical polymerization mechanism (including emulsion process) to yield various polymeric materials, including latexes and latex films. In this research, we present the conceptual process design and scale-up of producing soybean oil-based acrylic monomers (SBM) from crude soybean oil. Our preliminary life cycle assessment (LCA) results based on laboratory scale data have shown that production of SBM generates lower greenhouse gases and smog and depletes less fossil fuels compared to a commercial acrylic monomer (butyl acrylate) while it may cause higher ozone depletion and eutrophication.
Modeling the SBM production in industrial scale will allow us to refine our LCA results as well as estimate its total cost of production. The SBM production process in our study consists of a one-step transesterification reaction of soybean oil with N-hydroxyethyl acrylamide at the presence of catalytic amount of sodium hydroxide, followed by purification of monomer mixture and recycling of solvent. In modeling soybean oil-based monomer production facility, we use Aspen Plus to optimize the process through a detailed design including unit operation design of reactors, heat exchangers, decanters, flash tanks, filters, centrifuge and distillation columns. We determine the mass and energy balances via process simulation, aiming to optimize the process for net present value. The minimum selling price of SBM is estimated at different production capacities. A sensitivity analysis is conducted to identify the key parameters (yields, raw materials, process alternatives) for improving process economic potential. Finally, we compare the scaled-up production of the bio-based monomer with a functionally similar commercial monomer in technical, life cycle economic and environmental aspects.
8:50am - 9:10am
Techno-economic and Life Cycle Assessment Framework for Methane Storage in Advanced Porous Materials
Lawrence Berkeley National Laboratory, United States of America
Rapid development in advanced porous materials (APMs) may lead to a rise in the use of APMs for a broad range of applications. However, little is presently understood regarding the potential environmental, social, or economic benefit of APM development and scale-up. Here, we provide a broad analysis of methodological aspects and data requirements for bounding potential APM-based technology performance and application in the commercialization of biogas. Evidence suggests that lowering the cost of biogas upgrading (removal of CO2) and storage/transportation may allow smaller, more distributed sources of biogas to enter energy markets. Metal-organic frameworks (MOFs) are an emerging family of APMs that show great promise in this area, but they have not been yet studied from a system perspective, thus yielding limited insights into their long-term industrial applicability and sustainability. Here, we present a robust process model for evaluating the design and performance of hypothetical MOF-based industrial-scale systems for biogas treatment, upgrading, and storage. This model allows us to conduct ex-ante TEA and LCA of hypothetical methane storage systems so as to understand the scale of their potential deployment, appraise their subsequent life-cycle implications, and identify the process design areas that could be further improved. Detailed process modeling of the biogas treatment and upgrading activities, as well as the gas adsorption and storage, is conducted in ProSim and Matlab software for a range of biogas compositions, volumes, end uses, and set of experimentally known MOF materials. We discuss our methodology for isotherm curve fitting to experimental data for MOF materials, as well as our process for selecting plausible operating conditions. Preliminary simulations have been carried out for the cryogenic upgrading of 256 kg biogas, with a molar concentration of 1% H2S, 57% CH4, 1% H2O, 39% CO2 1% H2 and 1% N2, and the adsorption of the treated methane gas in MOF-508b. The cryogenic process is modeled for an operating pressure of 15 bar, while the adsorption takes place at 50 bar for an enhanced methane uptake. The total energy consumption is estimated at 739 MJ, 59% of which is attributed to the adsorption process due to the high pressure and cooling costs. Costs and impacts of the materials themselves are estimated using a prospective LCA approach, whereby industrial scale synthesis pathways are modeled in Gabi and ProSim using insights from lab-scale approaches, and emerging or analog industrial scale approaches. Synthesis pathways are chosen that allow for low solvent consumption and high metal recycling potential. To date, rapid analysis of emerging advanced materials in industrial scale systems has been a barrier in LCA research. Important knowledge gaps include: the durability of APMs to contaminants to ensure high cycling prior to disposal, and the exposure pathways and health impacts of APMs during manufacturing, use, and end of life. Our approach will allow the determination of the optimal operating window, in terms of the adsorption capacity and energy costs, for small and large-scale gas storage operation allowing for higher specificity in the overall LCA analysis.
9:10am - 9:30am
Integration of TEA and LCA for Sustainable Process Design- A Case Study of Wastewater Treatment Using Anaerobic Membrane Bioreactor (AnMBR)
Clemson University, United States of America
The objective of this study is to apply an integrated techno economic analysis (TEA) and life cycle assessment (LCA) approach to evaluate the economic and environmental aspects of a wastewater treatment plant using anaerobic membrane bioreactor (AnMBR) and compare the results with existing wastewater treatment process.
Technology developers are required to consider not only technical and economic aspects but also potential environmental impacts while developing sustainable new technologies. TEA is used widely as a tool to evaluate technical and economic feasibility of production systems or technologies in different industries. While performing TEA, detailed mass and energy balance are done on unit operation basis and the results are combined with capital and operating costs to evaluate the overall technical and economic impacts of that process. However, environmental aspects of the process or technology is not considered in TEA. On the other hand, LCA evaluates the potential environmental impacts of any product or process throughout its life cycle from raw material extraction to disposal (cradle to grave). For a sustainable design, technology developers need to tradeoff between economic benefits and environmental impacts in terms of maximizing the profit and minimizing the environmental burdens. This requires a consistent basis, functional unit, system boundaries and common set of assumptions for both TEA and LCA. As such, integration of TEA and LCA can provide significant benefits to technology developers to design sustainable technology instead of conducting them separately.
In this study, we apply an integrated TEA-LCA method to evaluate economic feasibility and environmental impacts of a wastewater treatment plant at Clemson University using AnMBR. Aspen Plus simulation tool is used to perform TEA and OpenLCA is used to conduct LCA. We compare the results with existing treatment process of the plant. The results from this study will provide insights to optimize different design parameters and make necessary improvements for sustainable design.
9:30am - 9:50am
Cost-effectiveness of continuous H2 production using integrated PV-electrolysis-storage systems
Massachusetts Institute of Technology, United States of America
The electricity sector has been at the forefront of global efforts to reduce energy-related greenhouse gas (GHG) emissions, through continued adoption of wind and solar photovoltaic (PV) generation, energy storage and fuel switching from coal to natural gas. Yet meaningful climate change mitigation efforts require identifying cost-effective emissions reduction strategies for all sectors, including traditionally difficult-to-decarbonize sectors like industry and transportation. For these sectors, while direct electrification could be expanded, the unique attributes of energy services, such as the need for high temperature heating for some industrial applications and energy density requirements for transport, could make it more cost-effective to use alternative energy carriers beyond a certain level of electrification. In this context, hydrogen (H2) is an appealing alternative energy vector, if it can be produced at scale in a cost-effective manner and without GHG emissions. In this study, we evaluate the near-term cost-effectiveness of continuous H2 production using technologies commercially available today: PV, low-temperature electrolysis, battery and H2 energy storage. Our approach goes beyond prior techno-economic assessments of electrolytic H2 production by explicitly accounting for the variability in hourly PV resource availability and its implications on process design, such as relative sizing of PV and electrolyzer and the magnitude and type of energy storage required for >95% plant availability. The integrated design and operations optimization framework used here also incorporates other operational aspects such as: 1) inter-temporal constraints associated with energy storage and electrolysis operation and 2) H2 compression prior to storage.
We evaluate the model for near-term projected costs of PV, low-temperature electrolysis, gaseous H2 storage and 4-hour battery storage, to reveal the possibility of standalone, continuous H2 production at levelized costs around $4/kg for locations in the U.S. southwest (e.g. Arizona or New Mexico). Further, the energy storage capacity needed to ensure 95% plant availability at peak H2 output can vary significantly (at least a factor of 2X) across locations with similar annual average PV capacity factor, due to the differences in seasonal variability of the resource. This highlights the importance of considering high temporal resolution of operations in evaluating the cost-effectiveness of renewable H2 production pathways. Since the optimal plant design for most locations uses PV capacity that is larger than electrolyzer capacity, the levelized H2 costs could be further reduced by exporting excess electricity to the grid. As an example, we evaluate the cost reductions achievable through excesss electricity sales for plant locations within the California Independent System Operator (CAISO) territory and historical locational marginal prices (LMP) for 2010-2017.