ALBERT

Description: The stimulation of renewable fuel production is related to the environmental issues resulting from the extraction and utilization of fossil fuels. Although corn-based ethanol is one of the leading renewable fuels and promises to mitigate these environmental impacts, it generates large volumes of wastewater with high concentrations of organic material (CODcr 〉 30,000 mg/L) and low pH (3.5–4.5), which leads to serious environmental concerns. A common method of treatment of distillery wastewater is the Dry Distilled Grain Soluble (DDGS) process, which separates liquid and solid fractions; however, a disadvantage of this process is its high energy consumption. Other commonly implemented methods are often costly and not environmentally safe. To minimize these problems, a flocculation process can be applied as a potential lower energy consumption process utilizing bioflocculants, which have been proven harmless to the environment. Therefore, the main goal of this study was to analyze the economic and environmental impacts of using bioflocculants instead of evaporation process in a corn-based ethanol plant. The procedures were evaluated by analyzing the Life Cycle Assessment (LCA) and Techno-Economic Analysis (TEA). From the results, it can be seen that the flocculation system can be an alternative process for effectively minimizing energy consumption during the production of DDGS, Distilled Wet Grains with Solubles (DWGS), and corn oil. The flocculation process achieved a significantly (28%) lower utility cost when compared to the conventional system. However, the overall fixed costs and annual operating costs for the flocculation system were higher than those of the conventional system. Additionally, both processes resulted in negative profit and a sensitivity analysis showed that the feedstocks cost substantially impacted the DDGS, DWGS, and corn oil production costs. Related to environmental aspects, the LCA results showed that the flocculation process achieved the lowest Global Warming Potential (GWP) of the several electricity supply technologies analyzed and presented a significant reduction in CO2 equivalent emissions when compared to a conventional system. The flocculation process resulted in approximately 57% lower greenhouse gas emissions.

Description: Technoeconomic analyses using established tools such as SuperPro Designer® require a level of detail that is typically unavailable at the early stage of process evaluation. To facilitate this, members of our group previously created a spreadsheet-based process modeling and technoeconomic platform explicitly aimed at joint fermentative‒catalytic biorefinery processes. In this work, we detail the reorganization and expansion of this model—ESTEA2 (Early State Technoeconomic Analysis, version 2), including detailed design and cost calculations for new unit operations. Furthermore, we describe ESTEA2 validation using ethanol and sorbic acid process. The results were compared with estimates from the literature, SuperPro Designer® (Version 8.5, Intelligen Inc., Scotch Plains, NJ, 2013), and other third-party process models. ESTEA2 can perform a technoeconomic analysis for a joint fermentative‒catalytic process with just 12 user-supplied inputs, which, when modeled in SuperPro Designer®, required approximately eight additional inputs such as equipment design configurations. With a reduced amount of user information, ESTEA2 provides results similar to those in the literature, and more sophisticated models (ca. 7%–11% different).

Description: Farmers in developing nations encounter high postharvest losses mainly attributable to the lack of modern techniques for threshing, cleaning, grading, and grain storage. Mechanized handling of grain in developing countries is rare, although the technology is effective against insects and pest infestations. The objective was to evaluate the cost-effectiveness of five grain handling techniques that have the ability to reduce postharvest losses from insect infestation. The five methods were metal silo plus all accessories (m. silo + acc.), metal silo only (m. silo), woven polypropylene plus phosphine (w. PP. + Phos.), woven polypropylene only (w. PP.), and Purdue Improved Crop Storage bags only (PICS). The functional unit used was handling 1 kg of maize grain. The cost analysis of each technique was calculated based on equations using a spreadsheet. The annual capital and operational costs of handling using m. silo + acc. or m. silo were very high, unlike the PICS, w. PP. + Phos., or w. PP. The annual capital and operational costs decreased as production scale increased. Food security (due to reduced insects and pest infestations) and financial prospects of farmers can improve when the grain is mechanically handled with m. silo + acc. or m. silo.

Description: Food waste (FW) is one of the most critical problems in the world. Most FW will be sent to landfills, generally accompanying some significant disadvantages to the surrounding environment. Fermentation is considered as another disposal method to deal with FW. In this study, using a techno-economic analysis (TEA) method, an evaluation of the economic impact of three different scenarios of FW fermentation is carried out. A SuperPro Designer V9.0 simulation was used to model a commercial scale processing plant for each scenario, namely, a FW fermentation process producing hydrolysis enzymes and featuring a 2-step distillation system, a FW fermentation process without enzymes, using a 2-step distillation system, and a FW fermentation process without enzymes, using a 1-step distillation system. Discounted cash flow analysis is used to estimate the minimum ethanol selling price (MESP), where the lowest MESP result of $2.41/gal ($0.64/L) of ethanol is found for the second aforementioned scenario, showing that, even without enzymes in FW fermentation, the product cost can be competitive when compared to the other scenarios considered in this study. This project thus reflects a significant positive economic impact while minimizing the environmental footprint of a commercial production facility.

Description: With the rapid development of the ethanol industry over the past few decades, research on distillers dried grains with solubles (DDGS), its main coproduct, has increased in recent years. However, research about the basic properties of DDGS lacks comprehensiveness. This study examined 16 DDGS samples from 10 ethanol plants in the Midwest U.S., and used standard laboratory methods to measure a series of physical and flowability properties. Results showed an average moisture content of 8.69% (w. b.), water activity of 0.55, angle of repose of 48.04°, shear strength of 0.0324 kg/cm2, geometric mean diameter (dgw) of 0.74 mm, geometric standard deviation (Sgw) of 1.72 mm, loose bulk density of 483.9 kg/m3, packed bulk density of 568.5 kg/m3, Hunter L of 56.71, Hunter a of 13.85, and Hunter b of 46.51. This study represents a step toward a more complete understanding of DDGS, and how various properties change as production practices evolve in the ethanol industry.

Description: The concern of food waste (FW) impact on the environment, societies, and economies, has triggered many researchers to find alternative ways to utilize these materials. FW can be high in glucose and other sugars (depending upon the food used) and has the potential to be converted into value-added products such as ethanol. Ethanol is an organic material that has a high demand from different industries for products such as fuel, beverages, pharmaceuticals, and other industrial applications. FW fermentation to produce ethanol may be a promising method, and might results in positive impacts on economies. However, it is a challenge for the product price to compete with that of corn ethanol due to low yield and the inconsistency of FW composition. Thus, to increase the profitability, a conventional fermentation plant integrated with a combined heat and power (CHP) system might be a great combination, and was analyzed in this study. Solid waste stream from the process can be converted into energy and could reduce the utility cost. Therefore, the main focus of this study is to evaluate the economic impact of this integrated system by estimating the minimum selling price (MSP) using techno-economic analysis (TEA) and compare to conventional plants without CHP. Results from this analysis showed that the MSE value for this integrated system was $1.88 per gallon ($0.50 per liter). This study suggests that an integrated system with CHP was found to be more economical and attractive to be implemented on a commercial scale.

Description: Although vegetables are important for healthy diets, there are concerns about the sustainability of food systems that provide them. For example, half of fresh-market vegetables sold in the United States (US) are produced in California, leading to negative impacts associated with transportation. In Iowa, the focus of this study, 90% of food is imported from outside the state. Previous life cycle assessment (LCA) studies indicate that food consumption patterns affect global warming potential (GWP), with animal products having more negative impacts than vegetables. However, studies focused on how GWP, energy, and water use vary between food systems and vegetable types are less common. The purpose of this study was to examine these environmental impacts to inform decisions to buy locally or grow vegetables in the Midwest. We used a life cycle approach to examine three food systems (large-, mid-, and small-scale) and 18 vegetables commonly grown in/near Des Moines, Iowa. We found differences in GWP, energy, and water use (p ≤ 0.001 for each) for the three food systems with the large-scale scenario producing more emissions. There were also differences among vegetables, with the highest GWP for romaine lettuce (1.92 CO2eq/kg vegetable) approximately three times that of leaf lettuce (0.65 CO2eq/kg vegetable) at the large scale. Hotspots and tradeoffs between GWP, energy, and water use were also identified and could inform vegetable production/consumption based on carbon and water use footprints for the US Midwest.

Description: Over recent years, the food industry has striven to reduce waste, mostly because of rising awareness of the detrimental environmental impacts of food waste. While the edible oils market (mostly represented by soybean oil) is forecasted to reach 632 million tons by 2022, there is increasing interest to produce non-soybean, plant-based oils including, but not limited to, coconut, flaxseed and hemp seed. Expeller pressing and organic solvent extractions are common methods for oil extraction in the food industry. However, these two methods come with some concerns, such as lower yields for expeller pressing and environmental concerns for organic solvents. Meanwhile, supercritical CO2 and enzyme-assisted extractions are recognized as green alternatives, but their practicality and economic feasibility are questioned. Finding the right balance between oil extraction and phytochemical yields and environmental and economic impacts is challenging. This review explores the advantages and disadvantages of various extraction methods from an economic, environmental and practical standpoint. The novelty of this work is how it emphasizes the valorization of seed by-products, as well as the discussion on life cycle, environmental and techno-economic analyses of oil extraction methods.