Grantee Research Project Results
Final Report: Development of a Recyclable Heterogeneous Catalyst for Biodiesel Synthesis Utilizing Waste Grease as Feedstock
EPA Grant Number: SU834322Title: Development of a Recyclable Heterogeneous Catalyst for Biodiesel Synthesis Utilizing Waste Grease as Feedstock
Investigators: Halaweish, Fathi , Mercer, Erin Jo
Institution: South Dakota State University
EPA Project Officer: Page, Angela
Phase: I
Project Period: August 15, 2009 through August 14, 2010
Project Amount: $9,970
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2009) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Chemical Safety , P3 Awards , Sustainable and Healthy Communities
Objective:
Given pressing energy issues, meeting the demand to preserve established social and economic structures will not come from any one resource, but will be a combination of alternatives that together accommodate the transportation industry and maintain independent mobility. Biodiesel is one of seven renewable fuels recognized by the 1992 Energy Policy Act. It has become the most researched alternative fuel for diesel engines, as it exhibits great potential to offset the diesel fuel demand and do so with environmental favor. The definition of biodiesel encompasses both unmodified vegetable oils, animal fats, and their alkyl ester derivatives. Its similarities to petro-diesel allow for distribution by the current infrastructure and direct use in diesel engines.
According to the National Clean Diesel Campaign (NCDC), a program established by the United States Environmental Protection Agency (EPA), reducing emissions from diesel engines is one of the most important air quality challenges facing the country today. One of the three regulatory programs introduced by the NCDC is the 2007 Heavy-Duty Highway Engine Rule, which aims to cut harmful pollutants from highway engines by more than 90 percent by 2010. Doing so would result in annual reductions of 2.6 million tons of nitric oxides and 110,000 tons of particulate matter when fully implemented. Two fronts have been working to make this possible: (1) focus on engine design to improve its efficiency and permit use of alternative fuels, and (2) development of alternative fuels that are sustainable from feedstock through their processing and in their combustion. In addressing the second goal, the research of cleaner burning alternative fuels from local feedstocks, and their introduction for mass distribution are necessary.
Biodiesel itself is a green alternative. Regarding emissions, biodiesel emits no aromatics and almost no sulfur. The alternative is 10 to 11 percent oxygen by weight, increasing its energy content. Ignition quality of diesel and biodiesel fuel alike is determined by its cetane number, where it must meet a minimum requirement of 40. Most fuel suppliers of conventional diesel record a cetane number of 40 – 45. A typical biodiesel blend will have a cetane number of 55, with reports up to 80. The high cetane number of biodiesel is a measure of its fuel quality, contributing to easier start in cold conditions and reducing the engine’s idle noise. As a renewable fuel providing up to 92% energy content relative to conventional No. 2 petro-diesel, biodiesel has the potential to decrease dependency on non-renewable sources and reduce contributions to global warming from toxic exhaust emissions.
Though the alternative is environmentally favored, enhancing industrial production must first be achieved so that the process itself is environmentally benign as well as economically affordable, from producer to consumer. Drawbacks of current biodiesel production systems call for innovative improvements that would decrease energy input in processing and permit use of less refined feedstock. For an alternative fuel to be considered completely environmentally benign, the entirety of production must meet green standards, from the harvesting of the feedstock to the burning of the final product. A more efficient means of producing the alternative fuel would allow an existing biodiesel industry to expand and a subsequent rise in manufacturing and consumption of bioenergy.
The research goal outlined by Phase I of the P3 Project focused on catalyst development as a means of improving biodiesel production. Specifically, the objective was to develop a recyclable catalyst for efficient conversion of innumerable feedstocks locally available within communities, including unrefined oils and waste grease. We sought a catalyst that would be durable under the varied feedstocks used, operate under mild conditions, and maintain its efficiency and product selectivity. While ensuring that environmental concerns were met in our development, consideration for the economic facet was made as well. Ultimately, catalyst efficiency was determined by overall monetary cost and the feasibility of the operation parameters for industrial-scale production.The objectives of Phase I were achieved with development of titanium niobate nanosheet catalyst for biodiesel processing. Synthesis of the nanosheets was optimized under mild conditions to result in a catalyst efficient in converting waste grease to a viable biodiesel product. Catalyst synthesis and the recycling measures are proprietary processes. Briefly, conversion was optimized under environmentally favorable conditions of moderate heat and low pressure. Processing used molar ratios of reactants, reducing waste product as well as investment cost. The developed catalyst is recyclable and maintains its efficiency over 20 times use, with no expected production decline in further use, again of environmental and economical benefit.
Summary/Accomplishments (Outputs/Outcomes):
Titanium nanosheet catalysts were synthesized to selectively react virgin oil and waste grease triglycerides to methyl esters. Final optimized method for titanium niobate catalyst synthesis is patent pending. Biodiesel conversion was monitored by nuclear magnetic resonance (NMR) imaging. Optimal catalyst was studied by X-ray diffraction (XRD) and BET analysis to determine surface character, pore size, and volume. From surface analysis results, the mechanism for the transesterification process was understood.
We can conclude that efficiency of conversion and the selectivity to produce methyl esters relies on the crystal phase of the titanium support and the nanosheet’s average pore diameter. Biodiesel transesterification requires anatase syn titanium dioxide support for selected product to be achieved. Synthesis of the optimum catalyst form was most dependent on heating temperatures during titanium nanosheet calcining, so as to preserve the anatase crystal. XRD analysis confirmed calcining at 500°C maintained the anatase crystal phase. Optimal pore size achieved under these conditions maintained an average pore diameter size of 111.0 Ǻ. Pores of larger diameters caused dispersion of the active sites, warranting the catalyst less effective in biodiesel processing.
No heat activation was required prior to application in biodiesel synthesis, determining anhydrous conditions are not necessary for catalytic efficiency. In studying application in biodiesel processing, we can conclude that biodiesel conversion by titanium niobate nanosheets is achieved via an acid catalysis. Fresh catalyst pH 0.35 confirmed the presence of the acidic protons and successful regeneration was achieved in recycling. Adsorption of reactant material and its desorption is efficient, as necessitated solvent washing is minimal. Conversion is maintained without any loss of efficiency over multiple uses by washing with the proprietary process developed. XRD analysis determined catalyst composition is the same between fresh catalyst, used catalyst, and regenerated catalyst, and is unchanged when applied under pressure.
Overall, complete transesterification of soybean oil was achieved by titanium niobate nanosheet catalysis under environmentally benign conditions which, too, would be economically favorable for large-scale processing. Application with waste grease feedstock was equally as efficient in the closed system, and conversion in the open system is possible with longer reaction times. Waste grease processing is of great value, both environmentally and economically. In conclusion, the catalyst synthesis developed under mild calcining conditions that result in efficient catalytic conversions offers overall benefits in biodiesel processing.
A comparison of ongoing biodiesel processing to date, feedstock, and the operating conditions is made in Table 1. The work collected and displayed is that carried out at the laboratory level, with the majority of large-scale facilities still operating under homogeneous base processing systems.
The industry is in hot pursuit of developing the most efficient means of manufacturing the alternative fuel at an economically feasible cost and environmentally favorable manner. As the variables to consider in the processing are vast and complicate the system, the research demand is high and labs have become focused on modifying catalysts to meet these provisions. The developed titanium niobate nanosheet catalyst shows great potential for success in large-scale operations, because of its mild reaction conditions and its being recyclable in use.
Conclusions:
Scale-up of a processing system using titanium niobate nanosheet heterogeneous catalysis would prove advantageous on all levels as a green process, allowing the catalyst to be recycled while permitting a wider range of waste material feedstock to be used; reducing final product cleaning steps; and resulting in a product that already has proven to be environmentally benign and accepted with an established system for distribution.
The cost of the catalyst is affordable and its favorability is enhanced by its recyclability. On a small purchasing scale, catalyst cost is $0.73/gram. Pricing in bulk would improve the cost. The processing also is economically affordable, as operation is at mild temperatures and atmospheric pressure. Molar amounts of methanol are used in processing and the reagents used to wash and recycle the catalyst are cheap. In addition to the green character of the biofuel product, the catalyst enhances the environmental favorabilty as it permits use of a waste product for production into a viable end product. The titania niobate system generates a market for local feedstock and agricultural producers in its ability to selectively process a range of feedstocks. Lastly, the final product and by-product can be used without further processing, which offers both an economic benefit and an advantage for the environment. Overall, the developed catalytic processing system would be economically feasible on a large-scale and environmentally sustainable in its entirety.
Based on both the uncertain supply of nonrenewable resources and the destructive results of their use, there is a need to develop alternative fuels that are renewable and environmentally benign to ensure that world intercourses progress. The possibilities are extensive, from equipping combustion chambers with better emission filters for petroleum-based gasoline and diesel, to modifying untapped renewable resources, so long as the resulting alternative is clean and affordable. Regardless, action must be taken worldwide with development catered toward the resources available and specific needs of individual communities.
Proposed Phase II Objectives and Strategies:
Based on the success of Phase I, our objectives for Phase II are specifically to:
- Scale-up biodiesel synthesis and optimize conditions on the large-scale.
- Design a reaction vessel module that can be used by local venues to collect and transport feedstock to a central station for processing.
- Establish a franchise that provides the vessels for collection, and grants oversight responsibility of maintenance care and profit from the product to the franchisee business owner.
In recognizing that sustainable energy will not be from one feedstock, the goal of our bench-top development was to design a catalyst that is capable of handling a range of feedstocks that vary in quality and type. Having achieved this at the bench-scale, implementation on a large scale could prove viable for the industry and beneficial in its entirety.
We have partnered with an independent local incubator investor for continuing development. With the research space and monetary support from the investor, we plan to purchase a large reactor vessel for study and optimization of reaction conditions on a large scale. In development of the large-scale processing system, we will build on the relationship established with South Dakota State University’s Department of Engineering to develop a uniform module that could be used in collecting, transporting, and reacting local feedstocks.
The intention is to make available a franchise for purchase to local venues. The franchisee would be responsible for the maintenance of the vessel and would profit in the resulting biodiesel product. As the catalyst is efficient among changing feedstock, a central site would be built for the franchisee owners to bring their vessels for processing. Processing design setup and heterogeneous catalyst would be provided to the investor of the central processing site. The envisioned setup parallels a grainery, which accepts harvest from the local farmers, weighs the yield, ships it off by truck or rail, and pays the farmers their returns. As the grain trucks collect and carry the feedstock to sale, the reactor vessels would collect oil and grease to be brought to the local plant where it is processed and made for sale.
Development of the catalytic system for bench-top work suggests that implementation of larger, biodiesel processing facilities would be equally sustainable for people, their prosperity, and the planet. Envisioned is distribution of feedstock collection vessels among local venues, designed for easy transportation and adaptable as a reactor basin at a central processing site. For people, it would provide a new market for a waste product and offer job opportunities in its collection, processing, and distribution; and doing so would generate revenue for a community, while preserving the environment in providing a clean burning fuel. The processing of an alternative fuel would preserve the social structures established around individual commute by the automobile and transportation of mass goods for wide-area distribution. For the prosperity of a community, a waste material would be given monetary value, and an affordable process would be established that allows manufactures to produce a profitable product while offering consumers an alterative fuel at a reasonable cost. For a catalyst to maintain the integrity of the planet, it must be sustaining of the environment in its application and support a reaction that results in an environmentally favorable end product. Large-scale biodiesel production from the developed heterogeneous catalyst would achieve this, and investment in scale-up would prove to have even greater positive effects for the global environment, initiated at a local level.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 3 publications | 1 publications in selected types | All 1 journal articles |
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Mercer EJ, Halaweish FT. Biodiesel synthesis via heterogeneous catalyst: titanium niobate nanosheet. Journal of ASTM International 2010;7(3):1-6. |
SU834322 (Final) |
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Supplemental Keywords:
Biodiesel synthesis, Heterogeneous catalysis, recyclable catalyst, titanium niobate nanosheets, yellow and brown grease, local feedstock, biodiesel processing vessel franchise,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.