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PublicationNGL/LPG Extraction from Marcellus Shale Gas(2015-05-04) Champagne, Jocelyn; Ordonez, Freddy; Zhang, ZhiyiThis process describes a design in which 6 million metric tons per annum of Marcellus Shale Gas is separated into its components through heat exchangers, pressure drops, and, finally, flowing through distillation columns. The goal was essentially to remove all of the methane gas as the overhead product of the heavy removal column and use the subsequent columns to fraction off heavier hydrocarbons. Heat exchangers could not remove sufficient heat from the feed prior to entering the columns and as a result, the overhead product for the heavy removal column consists of 84% by mole of methane and 15% by mole of ethane. Essentially all of the methane is being removed with the overhead product of the HRC but 85% of ethane is being removed here as well. By selling the major product (ethane) and the byproducts (propane and butane), our process design solution yields a net present value of $166.0 million, with an internal rate of return of 32.3%. The high profitability is secured in a sensitivity analysis on the ethane selling price, the total permanent investment, and the total fixed cost. PublicationEngineering Composite Oxide SOFC Anodes for Efficient Oxidation of Methane(2008-02-14) Kim, Guntae; Corre, G.; Irvine, J. T. S.; Vohs, John M; Gorte, Raymond JCeramic anodes for solid oxide fuel cells SOFCs were prepared by aqueous impregnation of nitrate salts to produce composites with 45 wt % La0.8Sr0.2Cr0.5Mn0.5O3 (LCSM)in a 65% porous yttria-stabilized zirconia (YSZ) scaffold. Scanning electron micrographs indicate that the LSCM coats the YSZ pores following calcination at 1473 K. Composites produced in this manner exhibit conductivities at 1073 K of approximately 1 S/cm in air and 0.1 S/cm in humidified H2. A SOFC with a composite anode composed of 45 wt % LSCM, 0.5 wt % Pd, and 5 wt % ceria exhibited maximum power densities at 1073 K of 1.1 and 0.71 W cm−2 in humidified (3% H2O) H2 and methane, respectively. PublicationAn Efficient and Safe Cooking Stove for Las Delicias, El Salvador(2017-04-18) Castaner, Maria; Li, Daniel; Minor, NicolasThe primary objective of this project was to design an efficient and safe cooking stove based on the resources available in El Salvador while ensuring it could be inexpensive to produce. The stove is a cuboid, 18"×18"×12" in dimension, and weighs 75 lbs. It has a top cover to cook on, and a unique three-chamber design: a chamber for combustion, a chamber to pump hot air into the combustion chamber with a bellows, and a third chamber to add insulation material. A ventilation tube connects the inner chamber with the exterior to safely vent flue gas to the outside. The stove is made out of stainless steel, and uses sand as an insulator. The product’s overall energy efficiency was calculated to be about 33%, and it requires approximately 19-20 minutes to boil 5 liters of water assuming a pot diameter of 14”. The estimated manufacturing cost of producing the first 200 stoves is $51.77 per unit, without including capital equipment costs. A unit can be priced at $65, which would give the manufacturer a 25% margin while maintaining competitiveness in the market against stoves such as Turbococina and Ecocina. The stove is estimated to cost a family $15 per month to operate, which corresponds to 50% in charcoal fuel savings compared to using an open flame. The stove can be manufactured using local labor and would take on average 6 to 7 hours to construct one unit. PublicationHeat Recovery from Natural Gas Liquefaction Process(2012-04-01) Calabrese, Michelle; Douglas, Kaitlin; Orinstein, Brendan; Vasansiri, Kritithy; Wang, MarisaThis project recommends several possible processes which expand and improve upon an existing section of a natural gas liquefaction plant. The section in question involves the combustion of the effluent fuel from the liquefaction process to produce usable work that drives the overall process. The existing process involves a simple gas turbine, which utilizes a Brayton cycle to convert combustion heat to shaft work. While the existing platform successfully provides power to the overall liquefaction process, the gaseous exhaust from this process leaves the system at elevated temperatures. The processes presented in this project seek to recover the heat that is lost through the exhaust and therefore, improve the thermodynamic efficiency of this system. Additionally, these processes more rigorously meet environmental standards concerning flue gas compositions and temperatures. Seven such processes are presented in this report. Each of these provides a net of 40MW, the required power to drive the liquefaction process, while performing at higher thermodynamic efficiencies than the simple gas turbine process. Rigorous economic analyses were performed for each of the presented processes. One recovery system has a lower net present value (NPV) than that of the simple gas turbine, four have approximately equal NPVs, and two systems have significantly better NPVs than that of the simple gas turbine. The optimal system has an NPV of $22 million and an internal rate of return (IRR) of 28.2% versus the simple gas turbine with an NPV of $12.3 million and an IRR of 20.3%. Further analyses of the economic and pricing assumptions may be required before final project approval. PublicationGreen Glycol: A Novel 2-Step Process(2019-05-14) Falcones, Ingemar; Golden, Sarah; Kowalchuk, MariaEthylene glycol demand is growing rapidly, particularly in the global polyethylene terephthalate markets.¹ Traditional production of non-renewable ethylene glycol involves steam cracking of ethane or the methanol-to-olefin process to obtain ethylene.6 In response to environmental movements, Coca-Cola® began creating ethylene glycol from renewably sourced ethanol, by producing the ethylene oxide intermediate in a two-step reaction process.² Novel research at Leiden University, entitled Direct conversion of ethanol into ethylene oxide on gold based catalysts, explores a catalyst which produces ethylene oxide in one step, showing potential for a more efficient renewable process.³ This project explores the scaling of the Leiden research to an industrial level. The makeup raw material flows accounting for the recycle streams in the process are 237,000 MT fuel-grade ethanol per year, 81,000 MT oxygen per year, and 26,000 MT carbon dioxide diluent per year. The design first reacts ethanol and low concentration oxygen feeds to form an ethylene oxide intermediate, as well as undesired byproducts. A series of separations isolate ethylene oxide for further reaction, while recycling unconverted feeds and diluents. EO is then hydrolyzed to form mono-, di-, tri-, and higher order glycols. The following separation series removes water for recycle, then isolates fiber grade (99.9 wt%) monoethylene glycol as the main product. The bottoms of this separation results in an ethylene glycol mixture that is sold as a slurry for additional revenue. A financial analysis of the process over a 15 year period shows that the process does not directly compete with the existing monoethylene glycol market. However, a 14.5% green premium on the selling price of monoethylene glycol would reach a 15% IRR and achieve profitability. Future work should be focused on investigating catalyst performance and reproducing similar reaction behavior in industrial-scale conditions. PublicationEffects of Delay on the Functionality of Large-scale Networks(2008-02-01) Papachristodoulou, Antonis; Jadbabaie, AliNetworked systems are common across engineering and the physical sciences. Examples include the Internet, coordinated motion of multi-agent systems, synchronization phenomena in nature etc. Their robust functionality is important to ensure smooth operation in the presence of uncertainty and unmodelled dynamics. Many such networked systems can be viewed under a unified optimization framework and several approaches to assess their nominal behaviour have been developed. In this paper, we consider what effect multiple, non-commensurate (heterogeneous) communication delays can have on the functionality of large-scale networked systems with nonlinear dynamics. We show that for some networked systems, the structure of the delayed dynamics allows functionality to be retained for arbitrary communication delays, even for switching topologies under certain connectivity conditions; whereas in other cases the loop gains have to be compensated for by the delay size, in order to render functionality delay-independent for arbitrary network sizes. Consensus reaching in multi-agent systems and stability of network congestion control for the Internet are used as examples. The differences and similarities of the two cases are explained in detail, and the application of the methodology to other technological and physical networks is discussed. PublicationCellular Agriculture(2022-04-19) Kim, Christina; Kishun, Amanda; Lubna, FahmidaCellular agriculture is a field of biotechnology focused on the production of animal products using cells grown in vitro . Traditional meat production consumes vast amounts of water, arable land, and feed crops, as well as driving deforestation, emitting large amounts of greenhouse gases, and creating large potential reservoirs for zoonotic diseases. As the global demand for meat increases, continuing to scale up the industry for slaughtered meat could have disastrous consequences for the environment. Growing cells in bioreactors creates the potential to drastically decrease land requirements, feed requirements, and other environmental impacts. For example, hindgut fermentation of feed, the main source of methane emissions from cattle farming, can be eliminated entirely by supplying the cells with pure glucose. This report proposes a process to produce 35 million pounds per year of a cultured ground beef product. The process starts with a starter colony of bovine muscle satellite cells, which are proliferated, differentiated to bovine muscle fiber, and then dewetted, mixed with plant-based fat, and extruded to the final product. Bubble column bioreactors are used for the seed train, final proliferation, and differentiation steps in order to adequately oxygenate large process volumes without threatening cell viability. The process shows profitability at a price of $100 per pound of product. The plant has a return on investment of 217%, an investor’s rate of return of 223%, and a cumulative net present value of about $2 billion over the plant’s lifespan. PublicationPurification of Pharmaceutical Grade Salmon-Derived Thrombin and Fibrinogen for Hemostatic Bandages(2015-05-04) Debes, Jesse; Elmongy, Hanna; Keenan, Shannon; Kirby, KristinHemorrhage due to trauma is the leading cause of preventable death among American soldiers, according the National Institute of Trauma. Uncontrollable bleeding is also seen regularly in civilian incidences of trauma and is a common major surgical complication. The human blood clotting process involves a complex cascade of tightly regulated enzymatic reactions. Two of the most important proteins in this cascade are fibrinogen and thrombin. Thrombin is an enzyme that activates fibrinogen monomers to form a polymeric fibrin network, forming the basis of a blood clot. During trauma, a state of consumptive coagulopathy, the body depletes these two proteins causing severe bleeding. A novel way to counteract hemorrhage is to supply additional thrombin and fibrinogen to the focal injury site. However, as of yet fibrinogen has proved technically challenging to produce recombinantly, and mammalian-based proteins carry the risk of pathogen transmission and immune response. Salmon-derived proteins, on the other hand, overcome both of these obstacles. DiamondStat is a novel hemostatic bandage that delivers fibrinogen and thrombin purified from salmon blood. It is a 4 x 4 inch adhesive bandage that delivers 10 mg/cm2 of fibrinogen and 90 units/cm2 of thrombin to effectively stop hemorrhage. The production of DiamondStat bandages begins with harvesting blood from salmon. Through a series of centrifugations and precipitations, prothrombin (a zymogen precursor to thrombin) and fibrinogen are extracted from the blood. Additional precipitations and filtrations further purify the fibrinogen solution to pharmaceutical-grade. The prothrombin is converted to thrombin in an immobilized snake venom catalyst column. Thrombin is then purified through an affinity column and ultrafiltration. Both thrombin and fibrinogen solutions are run through endotoxin removal columns and then sprayed onto pieces of gauze. The proteins are lyophilized onto the gauze and 2 the final bandage, which consists of fibrinogen and thrombin gauze pieces and an adhesive backing, is assembled. Bandages are sterilized via gamma irradiation and ready for use. At a capacity of 300,000 bandages per year and $800 per bandage, DiamondStat production is very profitable. It will yield an internal rate of return of 289.76% and a net present value of over $489 million. Extensive sensitivity analysis indicates that the project will be profitable in all likely scenarios. Investment in the DiamondStat processing plant is highly recommended. It is an economically viable project with the potential to save the lives of hundreds of thousands of American servicemen and women. PublicationCO2 Sequestration by Allam Cycle(2021-04-20) Chaturvedi, Raghav; Kennedy, Eric; Metew, SarronNatural gas powerplants account for 40% of the electricity generation in the United States and 617 million tons of CO2 emissions a year. The largest powerplants with carbon capture technology utilize a post-combustion absorption technology that must treat a large volume of flue gas and compress CO2 to pipeline specifications from near-ambient pressure. The Allam cycle, patented in 2013 by Rodney Allam, uses oxy-combustion and a supercritical CO2 stream as the working fluid to produce high-purity liquid pipeline CO2. While it was developed commercially at a 50-megawatt thermal (MWt) plant in 2018, the economics for a larger, 300 MW plant had not been documented. This project shows that under the current US tax code, the Allam cycle is less economical than the traditional natural gas combined cycle (NGCC) and NGCC with CDR. However, due to the over 99% capture rate, compared to 90% in post-combustion capture, the breakeven credit to traditional NGCC of $112/tonne for the Allam cycle is lower than the NGCC with CDR breakeven credit of $121/tonne. Similarly, for a desired IRR of 15%, the CO2 credit required for the Allam cycle is $163/tonne compared to $188/tonne for the NGCC with CDR. The Allam cycle provides increasingly better financial returns than the NGCC with CDR as the tax credit for sequestration rises. The results of this analysis were produced by first simulating both powerplants in Aspen Plus, and then conducting a discounted cash flow analysis for various scenarios. PublicationExport of Marcellus Shale Gas(2014-04-01) Marschang, Ryan; Lee, Steven; Hewitt, Ann; Moeller, TylerThe Marcellus Shale natural gas field that spans from West Virginia to New York is leading the recent surge in domestic energy production. Long an importer of natural gas, the United States will soon be able to export natural gas. Due to its low energy density however, natural gas must be converted to liquefied natural gas (LNG) before shipping to foreign markets. Liquefaction can occur at several different facilities: small-scale LNG plants, floating LNG operations, and retrofitted LNG import facilities. A design feasibility study is presented here to analyze the economics of retrofitting an existing LNG import facility into an LNG export plant. The existing import facility is the Dominion Cove Point LNG plant located near Lusby, Maryland. This study sizes the export facility at 5 to 6 million tons per annum (MMTPA), which corresponds to a feed of about 750 million standard cubic feet per day of natural gas (MMscfd). In this process, natural gas is first precooled by propane and then liquefied with a mixed refrigerant blend of methane, ethane, propane, and nitrogen. One challenge is to minimize the large amount of mixed refrigerant used in this process. This can be done by optimizing the composition of the mixed refrigerant to reduce the amount needed to liquefy the natural gas. After a comprehensive economic analysis, this proposed design is economically viable. This process has an estimated IRR of 23.5% and NPV of $219 million at a 20% discount rate, using an LNG selling price of $650 per ton. This 23.5% IRR is possible due to the retrofit advantages of some existing equipment and reduced construction time. Without these advantages, the IRR would be much less favorable at about 9.1%.