Grantee Research Project Results
Final Report: Microrefining of Waste Glycerol for the Production of a Value-Added Product
EPA Grant Number: SU833930Title: Microrefining of Waste Glycerol for the Production of a Value-Added Product
Investigators: Counce, Robert , Moore, Charles , Frymier, Paul
Institution: University of Tennessee
EPA Project Officer: Page, Angela
Phase: I
Project Period: August 15, 2008 through August 14, 2009
Project Amount: $10,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2008) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Air Quality , Pollution Prevention/Sustainable Development , P3 Awards , Sustainable and Healthy Communities
Objective:
The purpose of this project was to eliminate energy and resource waste from the production of biodiesel when crude glycerin by-product is disposed through aqueous waste treatment or direct environmental release and is not recovered. To accomplish this, a process was created that eliminates this waste stream by recovering this resource and converting it into value-added products, thereby taking advantage of the energy and raw materials invested in creating this material.
The scope of Phase I of this project was to develop and implement a strategy to create this process that includes selecting a product, identifying necessary technologies required, collecting relevant supporting data, evaluating potential from results of laboratory experiments, creating a process for making this new product, and analyzing the sustainability of this process. The first step was to identify alternate uses for the waste glycerin stream and screen these options for the most sustainable and practical pathway. Several different ideas were compiled and evaluated as possible processes for using this crude glycerin stream. The pathway chosen was to convert the glycerin material into a glycerol compost accelerant amended with phosphate salts and a free fatty acid weed killer. The path forward from this point was threefold. First, laboratory testing and experimentation for implementing a method of separating and purifying the crude glycerin by-product needed to be completed. The separation of the crude glycerin was carried out by acidification of the material followed by gravimetric separation to obtain a predominantly free fatty acid (FFA) material, a partially purified glycerol material, and a layer of solid phosphate salt. Methanol was removed from the products through a volatile vapor recovery system and stored for potential recycle to biodiesel producers. Next, the efficacy of the FFAs as a weed killer and the glycerol and salts as a compost accelerant was determined. The partially purified glycerol product amended with phosphate salts was added to compost piles to determine their effect on the rate of composting. Multiple compost piles were treated with various amounts of glycerol-salt accelerant and temperature readings were taken to measure effectiveness of this accelerant against a control. The efficacy of the free fatty acid weed killer was assessed by applying an amount on living plants and comparing their growth to a control. Next, a design study highlighting technology selection, process and flow sheet development, and economic, environmental, and sustainability evaluations also needed to be performed. The design element of this project was aimed at developing a plan for a facility that can produce the compost accelerant and free fatty acid weed killer from the crude glycerin. This facility was sized to serve a geographic region with an amount of biodiesel produced by individuals comparable to that of the metropolitan Knoxville, Tennessee area. Last year in Knoxville, 90,000 gallons of B100 biodiesel were consumed. Much of this biodiesel was regionally produced, providing ample feedstock for a production facility to make the desired products from by-product glycerin. The amount of microproduced biodiesel was estimated to be 8% of the 90,000 gallons. From this amount, an annual amount of crude glycerin produced on a micro-scale was determined to be 1,800 gallons. This design study developed a separation process to make the desired products from the crude glycerin and produced estimates of operating and capital costs for such a facility. This information was evaluated to determine the overall sustainability of the process and its effects on society and the environment. This was done by applying EPA’s EPIWIN software to estimate the bioaccumulation, toxicity, and environmental persistence for the main product streams.
Proposed Phase II Objectives and Strategies:
The objectives of Phase II are: (1) to implement the design produced in Phase I to refine crude glycerin waste from the production of biodiesel on the campus at the University of Tennessee, (2) to conduct a more comprehensive study of the efficacy of refined products, and (3) to complete a thorough analysis of the economic potential of the process and a study of possible commercialization strategies.
To accomplish these objectives, several strategies will be used. In order to implement the general design created in Phase I to refine crude glycerin waste, a demonstration facility will be constructed and operated on the campus of the University of Tennessee. The demonstration facility will be called the University of Tennessee Glycerin Refinement Pilot Plant (UTGRPP). It will be constructed and operated downstream of the currently operating biodiesel plant managed by the Mechanical Engineering Department at the University of Tennessee. This facility will operate to refine crude glycerin from commercial and micro producers of biodiesel around the greater Knoxville area and to demonstrate the process to further generate interest from biodiesel producers outside the local area.
After the implementation process, the focus of the work of Phase II will be to perform a comprehensive assay of the efficacy of the products obtained from the acidulation process. During Phase I, it was determined that the glycerol can be used as a compost accelerant and the free fatty acids as a weed killer. However, the most efficient amounts of these substances to use have yet to be determined. Phase II will continue research on the effectiveness of these products by having the students on the Phase II team conducting further composting and weed killing experiments to determine how to utilize the product most efficiently. They will also continue research on the effectiveness of the salt layer as an environmentally compatible fertilizer, since it has been determined that this material can be included in the composting with the glycerol. The raw material for these tests will come from any biodiesel waste from the University of Tennessee Biodiesel Production Pilot Plant (UTBPPP) team, SunsOil, LLC, and the Clean Fuels Coalition of Knoxville (an organization of biodiesel home brewers in Knoxville). The inclusion of other organizations in this project will help increase people’s knowledge of what the UTGRPP team is accomplishing, and how their work impacts the sustainability of biodiesel production. Excess products will be donated to the UT Demonstration Gardens on the UT campus, which will give insight into larger scale environmental benefits of the products, such as the use of the phosphates as fertilizers for gardening. Various concentrated acids will be tested to determine the optimal choice considering economic and environmental impacts. Work will also be done with the University of Tennessee’s Department of Mechanical, Aerospace, and Biomedical Engineering to further develop the design of the glycerol refinement facility including improved designs for methanol recovery. With their help, the Phase II team should be able to continue optimizing the mechanical aspects of the design to promote efficiency and potentially lower capital and operating costs to increase the process’s economic feasibility.
Summary/Accomplishments (Outputs/Outcomes):
As a result of Phase I, a process to refine crude glycerin waste to value-added products was designed. An economic analysis was performed to determine the capital and operating costs for a commercial facility that implements this design. Using the estimated 1,800 gallons of raw material per year, it was determined total annualized cost of glycerol accelerant was found to be $21.18/gallon, the FFA annualized cost was $19.12/gallon, and the annualized cost of producing phosphate salts is $1.91/lb. This results in a manufacturing cost for the glycerol accelerant of $10.60 per five bushels of composting material (based on using 2 liters (~1/2 gallon) per application). The purpose of the experimental design portion of this project was to determine the efficacy of the selected refining technique and to determine the performance of the resultant products. This was carried out by measuring the effect of the glycerol and phosphate salts on a compost pile and the effect of FFA material as weed killer. It was essential that these products perform with minimal environmental impact. In this study, common agricultural activities such as composting waste into a natural fertilizer and the removal of unwanted plants by weed killer are examined. These methods were chosen as a response to the ever-growing need to replenish and aid the degrading environment by recycling waste material back into biodegradable products.
Before determining the efficacy of the compost accelerant and FFA weed killer were in application, an effective way to generate these products from the crude glycerin had to be developed and tested. The chosen method was an acidification reaction. Phosphoric acid was added to the crude glycerin material, vigorously agitated, and then allowed to settle. Through this process, the dark, viscous liquid turned to a lighter color through acidification settled into three distinct layers that could be separated gravimetrically. After accumulating a sufficient amount of each product, performance tests of the product streams were conducted. Two sets of experimental tests were implemented; the first set of tests was to determine the effect of adding glycerol amended with phosphate salts as an accelerant to a compost pile. The second set of tests was to determine the effectiveness of using the FFA material as a weed killer.
Composting is a common agricultural practice that farmers and other agricultural businesses employ to create an inexpensive organic fertilizer. This is carried out by the catabolism of carbon and nitrogen sources via aerobic metabolism by bacteria and fungi. To determine the performance of glycerol amended with phosphate salts as a compost accelerant, a temperature profile was obtained for compost piles to monitor levels of microbial activity. Six compost piles with three treatments were observed and measured for this experiment.
The separated free fatty acid material was tested to determine its performance as a weed killer, and whether a foliage application or soil application showed significant differences in resultant effect. Three treatments were used on four plant specimens to determine if the FFA material would result in significant negative effects to the plants within a week. The FFA material had obvious deleterious effect on healthy plants. During the seven days that elapsed after the application of the FFAs, the plants experienced significant negative effects, with the foliage turning brown. Applying the FFAs to the foliage of the plant was more effective at inhibiting plant growth than applying the FFAs to the soil surrounding the plants.
It was determined that the overall process of recovering crude glycerin by means of acidulation was sustainable. This is from taking a waste product that may accumulate in the environment or be sent in large amounts to waste treatment and converting it into value added products to be used in the environment. In general, a waste product is converted into a useful product used and then used in agricultural actions such as composting and weed killer. In addition, this process eliminates a potentially harmful waste product containing a large amount of methanol and converts it into useful methanol-free products.
Conclusions:
The purification of waste glycerin material from a biodiesel production process to make compost accelerant and natural weed killer creates value added products from a waste stream. The original intent of this project was to develop a prototype system for the small scale, or micro-refining of crude glycerin produced locally by biodiesel micro-manufacturers. While the original Phase I proposal suggested that the highly refined glycerol could be sold commercially as a food or cosmetic grade additive, subsequent economic analysis in this study indicated that commercial sale would generate only minimal revenue on such a small scale. This is a consequence of the recent saturation of the world glycerol market caused by increased biodiesel production. As a result of this situation, the product of the refined biodiesel waste stream was changed from high purity commercial grade glycerol to a compost accelerant and a weed killer.
This project therefore creates an innovative solution to the problem of disposing os biodiesel production waste. Organic fatty-acid based weed killers were commercially available and the ability of glycerol to accelerate the composting process had been explored before this initiation of this project. The focus of this project was to validate the efficacy of the fatty-acids, glycerol, and salts derived from biodiesel waste in the aforementioned applications and then design an economically feasible facility so that these products can be produced by micro-manufacturers of biodiesel around the world. From the result, it was clear that glycerol-salt mixture and FFA were effective in accelerating composting and in killing weeds, respectfully.
This project makes a significant contribution to the advancement of sustainable micro-scale biodiesel production. A substantial obstacle facing individual micro-manufacturers of biodiesel is waste disposal. This project developed a blueprint for a waste recycling system that can be used by a co-op of biodiesel producers in any community. By providing a feasible, easily implemented, and environmentally sound solution to the biodiesel waste disposal problem, this project provides a sustainable waste disposal solution for micro-manufacturers of biodiesel worldwide. Given the goals of this project, thoughtful considerations were taken to concentrate on a solution that is aligned with the principles of the P3 program. At the onset of this project, an economically and environmentally promising solution to the problem of biodiesel waste was determined: conversion of waste to weed killer and compost accelerant. Testing of the efficacy of these products was conducted to ensure acceptable performance. Finally, a design study was completed, laying the foundation for a pilot plant to effect these goals. The completion of this project, in addition to anticipated future consequences thereof, has significant positive effects on people, prosperity, and the planet. A niche biodiesel micro-manufacturing community is directly served by this project, but its impact reaches a much greater population. By providing a means of converting waste to natural consumer products, this increases the economic viability of small scale biodiesel production. Making biodiesel production more economical will serve to increase the production of sustainable fuels which will lead to a smaller global environmental footprint. Biodiesel producing communities will realize significant environmental benefits due to the elimination of waste disposal.
Journal Articles:
No journal articles submitted with this report: View all 1 publications for this projectSupplemental Keywords:
Glycerin refinement process, biodiesel waste recovery, alternative glycerol uses, University of Tennessee glycerol refinement,, RFA, Scientific Discipline, Sustainable Industry/Business, POLLUTION PREVENTION, Sustainable Environment, Energy, Environmental Chemistry, Technology for Sustainable Environment, Environmental Engineering, sustainable development, environmental sustainability, alternative materials, biomass, alternative fuel, biodiesel fuel, energy efficiency, energy technology, alternative energy sourceRelevant Websites:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.