Grantee Research Project Results
Final Report: A Robust Process for Biodiesel Production Using Supercritical Methanol
EPA Grant Number: SU833926Title: A Robust Process for Biodiesel Production Using Supercritical Methanol
Investigators: Babcock, Robert E. , Thoma, Greg , Hestekin, Jamie , Penney, Roy
Institution: University of Arkansas
EPA Project Officer: Page, Angela
Phase: I
Project Period: August 15, 2008 through August 14, 2009
Project Amount: $9,798
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2008) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Air Quality , P3 Awards , Sustainable and Healthy Communities
Objective:
The overarching purpose of Phase I was to test, at the bench scale, a continuous supercritical methanol reactor, and to determine the feasibility of implementing the technology at full scale. Specific objectives in reaching this purpose included:
- Choose a viable feedstock
- Perform experiments for oil extraction
- Design, build and operate a continuous supercritical methanol reactor
- Design and simulate full scale biodiesel facility
- Perform life-cycle and economic analysis on full scale design
- Prepare a Phase II P3 project to demonstrate the entire biodiesel process
Project Scope: The students performed extensive review of the literature regarding both feedstock selection and alternate conversion technologies. After the system was designed and constructed, the students performed all experiments in the laboratory.
Proposed Phase II Objectives and Strategies:
As part of the work completed in Phase I, a bench scale continuous supercritical methanol (SCM) reactor was built from commercially available components. The reactor produced biodiesel at 16mL/minute. The utilization of this robust process offers developed and developing nations the capability of producing a renewable, non-petroleum based diesel fuel. The ability of the supercritical methanol process to handle feedstocks with diverse compositions, without the use of a catalyst sets this technology apart from other biodiesel production methods.
Phase I also included detailed research of feedstock options. It was desired to choose a feedstock that could offer a sustainable alternative to the use of fossil fuels and demonstrate the diversity of the supercritical methanol process. After a thorough investigation, algae oil was chosen as a feedstock because of its ability to satisfy these desires. As discovered during Phase I, algae can be used successfully to remove nutrients from polluted water streams while absorbing carbon dioxide from the atmosphere providing significant environmental benefits. The use of algae can also illustrate the importance of the supercritical methanol process because of the differing oil composition contained in the multiple different species of algae that exist.
For Phase II, the technical challenges include (1) improving the efficiency of algae oil extraction yield; (2) optimizing the reactor operation with multiple runs; and (3) finalizing a design to produce biodiesel from algae. To address sustainability implementation, students will (1) develop a economic analysis for implementation of a full scale facility (1MM gallons per year) on the Mississippi River; and (2) perform a life-cycle analysis for this facility.
Partnerships have already been developed with corporations utilizing Algal Turf Scrubbing (ATS) in Maryland and Florida. Building on those relationships, students working on Phase II will work alongside Biological Engineers at the University of Arkansas to help harvest algae from a recently built ATS system in Springdale, Arkansas. These students will travel to the Springdale facility, 15 miles away from the University of Arkansas campus, on a weekly basis to harvest the algae biomass. Because the quantity of biomass produced by the ATS system in Springdale is limited, algae will also continue to be collected from partners in Florida and Maryland. Mark Zivojnovich, vice president of project development at HydroMentia Inc., has agreed to supply Phase II with enough algae necessary to test and run the extraction unit that has been proposed.
Summary/Accomplishments (Outputs/Outcomes):
A literature review was conducted in order to insure the feedstock choice had the potential to bring about positive impacts in making progress toward sustainability. The use of algae for a biodiesel feedstock was chosen for the many benefits it provides. Algae produced via the ATS system removes carbon dioxide from the atmosphere, removes nutrients from polluted water, provides opportunity for production of other bio-fuels (e.g., butanol or ethanol from the cellulosic component of the algae) and environmentally friendly fertilizers, and decreases the consumption of fossil fuel.
Experiments were performed to determine the most effective method for extracting algae oil through their virtually indestructible cell walls. The following methods were tested: mortar and pestle, Waring blender, hexane extraction alone, salt-water solution, glycerol solution, and urea solution. It was ultimately concluded that lysing the cells with an osmotic shock using glycerin would be the most effective method to release the oil for extraction with hexane. The fraction of oil extracted, on a dry solids basis ranged from 0.37% to 2.67%. The mortar and pestle method gave the highest yield of 2.67%. Unfortunately, the mortar and pestle method requires dried algae and grinding of dry algae; thus, costs on are prohibitive for a full scale plant. The least effective method, surprisingly, was using an 8 M urea solution to weaken the cell wall hydrogen bonds; we believe this is because there is a relatively low quantity of cellulose in the algae cell wall. Salt and glycerol solutions utilize osmotic shock as the cell disruption mechanism. The salt solution was actually more effective than the glycerol, yielding 2.53% vs. 2.2%. However, salt solution lysing is not practical for a full scale plant design because the salt must be recycled and the cost of removing water required for salt recycle is prohibitive.
Constructing a reactor that can run continuously is only a small part required to prove the viability for producing biodiesel at a larger level; however, the ability to create such a reactor provides evidence that the chosen technology has potential for being implemented on a full scale. Students at the University of Arkansas designed and built a continuous supercritical methanol reactor for the production of biodiesel from commercially available materials. The continuous supercritical methanol reactor is one of the first of its kind. The supercritical methanol reactor was tested with a variety of triglyceride and free fatty acid (FFA) feedstocks to demonstrate its robustness. The experimental runs proved that high conversion, ranging from 60% to 85%, could be obtained with feeds ranging from 100% FFA to 100% triglycerides.
A full scale simulation was designed using Pro II process simulation package. The material and energy balance information provided by the simulation allowed students to perform a streamlined life cycle analysis. Because glycerin is used to lyse the algae cell, and it is not economical to recover and recycle the glycerin, it is sent with the algae biomass to an anaerobic digester where methane is produced and used on site for heating needs; the excess is sold off site, and an avoided product credit is claimed for this natural gas. Due to the very heavy use of glycerin, this process does not yet make positive environmental impacts compared to alternative biodiesel production methods. If a source of waste glycerin can be found, it would not carry an environmental burden into this process, and the algae biodiesel becomes very favorable. This highlights the reason that algae have not yet become a viable alternative feedstock: it is extremely difficult to extract the oil. This also points clearly to the need for additional research in this area.
Although it is well known that a full scale process to produce biodiesel from algae is not economical as an industrial commercial venture with the current technology, the team evaluated the venture as a government funded project and determined that the project is revenue neutral; i.e., the venture does not cost the taxpayers. The proposed demonstration plant provides 71 permanent, high playing jobs in addition to removing fossil fuel from our fuel mix, which reduces CO2 emissions. The proposed capital estimate of the commercial scale plant is summarized below. The algal growing ponds cost $25,000,000 and the total installed cost of other equipment is $15,000,000, giving a total capital cost of $40,000,000. The project is essential to our economic and national security; thus, it should be financed with the sale of US Treasury Bonds bearing an interest rate of 4.00% p.a. for 30 years. After the bonds mature in 30 years, additional bonds will be sold to repay the original bondholders. The yearly interest on the bonds is $1,620,000 will be paid by the venture, resulting in no net cost to the US taxpayers.
Conclusions:
This P3 Phase I project defines a scenario for producing fuels (biodiesel) from a renewable resource (algae) which will, with further research to improve extraction of oil from the algae, benefit people, improve economic prosperity and eventually reduce the impact of economic activity on global warming by reducing the emissions of CO2 from use of fossil fuel diesel.
The original objective of the P3 project was to investigate the technical and economic feasibility of utilizing a high pressure, high temperature supercritical methanol reactor to esterify, hydrolyze and transesterify fatty acids and triglycerides (the components of algae oil). This objective was achieved and, additionally, a pilot plant unit was designed for Phase II, a preliminary design was completed for a full scale demonstration plant and a life cycle and economic analysis were accomplished.
Integration of P3 Concepts as an Educational Tool
Nine Chemical Engineering Seniors and 1 Chemistry Senior, the GREENIES (Generating Renewable Energy for Economic Nourishment and Improvement of Environmental Sustainability) team, have participated in this Phase I P3 sustainability competition. The chemical engineering students are participating to fulfill their course requirements for the chemical engineering capstone senior design course and the chemistry major is receiving course credit for a technical elective. This P3 project satisfied more than the requirements of the capstone design course, which includes performing heat and mass balances; preparing process flow diagrams; designing, scaling-up and costing process equipment; performing economic analysis and using the latest and best process simulators. This competition allowed the students to obtain extremely valuable experience with laboratory experimentation, which is not a normal part of the capstone design. Additionally, the organic chemistry component of the P3 was excellent. The hands on experience of designing and building experimental equipment apparatuses from scratch, conducting experiments, analyzing samples and presenting results are part of the invaluable experience which this P3 project offered.
The GREENIES designed a full-scale demonstration plant to produce biodiesel. The economics of this plant were determined. Using the demonstration plant economics as a basis, a life-cycle analysis was performed. This project linked knowledge from all undergraduate courses into the design of a demonstration plant which could have far reaching outcome to provide people renewable energy, while prospering and helping save the plant from global warming.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 1 publications | 1 publications in selected types | All 1 journal articles |
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Type | Citation | ||
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White K, Lorenz N, Potts T, Penney W, Babcock R, Hardison A, Canuel E, Hestekin J. Production of biodiesel fuel from tall oil fatty acids via high temperature methanol reaction. FUEL 2011;90(11):3193-3199 |
SU833926 (Final) |
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Supplemental Keywords:
biodiesel, supercritical methanol, algae, renewable, sustainable, energy, environment, alternative fuel,, 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, carbon credits, 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.