Synthesis of energy efficient separation processes using distillation and membranes

With 90 – 95% of all separations in the chemical and petrochemical plants, distillation is among the predominant unit operations. According to one estimate in the literature, there are approximately 40,000 distillation columns in operation in the U.S. with energy consumption equivalent to 1.2 million barrels of crude oil per day. It is therefore essential that more efficient distillation configurations, which are also cost effective, be identified for all applications. However, the prevailing industrial practice whereby a distillation train is synthesized based on heuristics, experience, and creativity of the process designers is far from optimal. We will first discuss our recent work on the synthesis of nonazeotropic multicomponent distillation configurations. It is known that the number of possible distillation configurations increases rapidly in hundreds and thousands as the number of components in a n – component mixture increase beyond three (n \u3e 3). Therefore, the first challenge for a process engineer is to be able to draw all feasible configurations and then narrow down the search to a set of suitable candidates. An easy to use systematic procedure to draw distillation column configurations to separate a nonazeoptropic n – component mixture into n product streams each enriched in one of the components will be presented. We will then share our success with nonlinear programming to optimize thousands of distillation configurations with respect to total heat duty. Next, progress in energy saving distillation columns will be discussed that will include, (i) synthesis of new heat and mass integrated columns, and (ii) solution for a long standing challenge of controlling vapor split in dividing wall columns. The new method enables process intensification whereby any thermally coupled column configuration can be drawn as a divided wall column configuration leading to reduction in the number of columns. For membrane based separations, when high product purities and high recoveries are required, use of a cascade is generally needed. Due to cost considerations, it is desirable to minimize the number of recycle compressors/vacuum pumps used in such cascades. Historically this led to drawing of such cascades through inventive activity of process engineers. Here we will present a method to systematically synthesize such membrane cascades. Finally, we will end the presentation by drawing analogy between distillation and membrane processes for the separation of a multicomponent mixture

Role of Natural Gas in America\u27s Energy Future: Focus on Transportation

The energy landscape of the United States for the past century has been dominated by the use of fossil fuels namely coal, petroleum, and natural gas (NG). While coal usage was dominant during the early 1900’s, petroleum has been dominant ever since the second half of the 20th century owing to increasing use of liquid fuels, gasoline and diesel, for transportation. In contrast, NG consumption in the U.S., currently at ~25% of total primary energy use, has only been steadily increasing since the early 1990’s (BP, 2012). However, the last decade has seen rapid growth in U.S. NG consumption as a result of falling prices stemming from the surge in domestic gas reserves. According to the U.S. Energy Information Administration (EIA), currently the total recoverable U.S. natural gas reserves are estimated at 2214 trillion standard cubic feet (tcf). For an annual NG consumption of 24.1 tcf (in 2010), U.S. NG reserves are estimated to last close to 92 years. Not surprisingly, there has been a growing interest in expanding NG use in the U.S. energy supply. Here, we analyze the potential for using NG to meet the energy requirements of U.S. light duty vehicle (LDV) fleet and the associated energy policy implications. Compared to coal and petroleum, natural gas by virtue of its higher hydrogen to carbon ratio, could contribute to reducing greenhouse gas (GHG) emissions with little sequestration efforts (Burnham et al., 2011)

Database for Solar Energy Group

Copper zinc tin sulfide (CZTS) is the abundant quaternary semiconducting compound which could be used to make solar thin film. Even though its efficiency is lower than the silicon based film, the cost of CZTS solar film will be lower compared to the current silicon based film. Therefore it is really worth to do research and make improvement on its efficiency. So far, the solar energy group already collected a great bunch of data, which could be employed to guide the future experiment. Hence, it is really necessary to build a database to arrange the information we got. Our project this summer is to design such a database, which will not only focus on the searching function, but also try to make it able to finish some basic calculation. Furthermore, We also need to consider about the flexibility to the form of data. For instance, we need to make data be easily inserted to other softwares, like Matlab and SAS, to do some more complex calculation and regression. As for the methods, after comparing different software, we decide to employ MS Access to build the database. In addition, I also need to get some feedbacks from the members from the group to improve the design. I think at the end of this program we should have a proper database which will enhance the research in statistic and mathematic perspective

Photolithography in Fabrication of Thin-film Solar Cells

Solar energy has steadily increased its efficiency and cost-effectiveness throughout the past three decades and seems poised to compete with current primary energy (natural gas, oil, coal) as the need for alternative energy sources rises. One type of solar cell, thin-film cells, often relies on use of permanent photomasks in order to imprint a pattern onto the front metal contact. However, these machined metal masks are rigid and do not allow for different designs to be explored as current masks encounter difficulties in machining grids thin enough for optimization. Photolithography, traditionally used in the microfabrication field, provides a method in creating flexible and easily interchangeable designs to duplicate patterns onto solar cell contacts. First, a positive photoresist was spun onto a glass plate with a deposited conductor (ITO). Second, exposure of the photoresist was performed in a dark environment through near UV LEDs in order to polymerize the photoresist in accordance with the mask. Third, photoresist was developed and processed with a nickel/aluminum coating through an electron beam depositor. Parameters were optimized at each individual step of the procedure along with a variety of photoresist thicknesses and designs. Photomasks were printed on a laser-jet printer featuring grids of .5mm wide and produced clean copies of the masks with minimal walling. The implementation of photolithography in exploring more options to engineer more efficient inorganic solar cells hints at a promising future through its flexibility

Partial-sum queries in OLAP data cubes using covering codes

A partial-sum query obtains the summation over a set of specified cells of a data cube. We establish a connection between the covering problem in the theory of error-correcting codes and the partial-sum problem and use this connection to devise algorithms for the partial-sum problem with efficient space-time trade-offs. For example, using our algorithms, with 44 percent additional storage, the query response time can be improved by about 12 percent; by roughly doubling the storage requirement, the query response time can be improved by about 34 percent

Modular Scale Process for Sour Gas Removal and Disposal

The purpose of this research is to find methods for removing sour gas, H2S and CO2, from shale gas streams and properly dispose of them for small scale gas processing plants. H2S and CO2 are both contaminants found in shale gas, and they must be removed in order for the natural gas to meet environmental and gas pipeline regulations. Currently, at regional scale plants, the amine sweetening process followed by the Claus process are used to remove and treat the sour gas, however these do not work for small scale plants. Three alternative methods were explored to accommodate small scale gas processing plants, in order to retrieve the shale gas in remote areas. The first method is the membrane separation process, which uses membranes to separate sour gas from natural gas. The second method is adsorption, which uses amine sorbents to adhere to the sour gas molecules. The third method is the hybrid method, which combines both the membrane separation process and amine sweetening process. Zinc oxide may be able to serve as an alternative to the Claus process for small scale gas processing plants

Can Ethical Leaders Enhance Knowledge Sharing? The Role of Psychological Capital and Anticipated Reciprocal Relationships

The aim of the paper is to empirically investigate the influence of ethical leadership and psychological capital on knowledge sharing in business organizations. Furthermore, the paper investigates the mediating role of psychological capital and moderating role of anticipated reciprocal relationships in the relationship of ethical leadership with knowledge sharing. The analysis has been conducted on data gathered from 248 members of information technology (IT) companies by making use of survey questionnaire. Hypotheses are tested by analysing the data using structural equation modelling (SEM) and PROCESS macro. The study found that ethical leadership and psychological capital have positive effect on knowledge sharing. Ethical leadership also impacts psychological capital positively. Further, psychological capital acts as a mediator and anticipated reciprocal relationships act as moderator in the relationship of ethical leadership and knowledge sharing. This study establishes new antecedents of knowledge sharing, emphasizes the importance of ethical aspects of leadership in managing knowledge resources and enrich literature of Knowledge Management (KM), leadership, positive organizational behavior and human resources management. It further gives new perspectives to practitioners by recognizing the significance of ethical leadership, psychological capital and anticipated reciprocal relationships to enhance knowledge sharing. To the best of authors’ knowledge, this study is one of few initial studies to examine the linkages between ethical leadership, knowledge sharing and psychological capital as well as the role of anticipated reciprocal relationships therein