Mathematical Models to Compare Shale Gas Utilization Processes.

The migration towards more renewable sources of energy with the intention of controlling and reducing fossil fuel emissions has become the focus of many. Because of this, there is an existing demand to develop more environmentally friendly methods to produce energy. Recent studies have shown that shale gas is a comparatively cleaner alternative to other fossil fuel sources since it has lower concentrations of sulfides making it an attractive alternative to help transition into cleaner technologies. Shale gas production in recent years has grown due to advances in drilling like horizontal fracking methods which has led to a revolution and has created opportunities for the development of multiple shale utilization technologies. In order to find the most efficient and economically viable hydrocarbon conversion technologies, various technology alternatives, feedstock, and products need to be evaluated for different feedstock compositions and product portfolios. In this work we are working towards creating a superstructure framework which will enable a rapid screening of various candidate technologies. Evaluating in silico would show the benefits of candidate process technologies, to determine future direction of research by setting performance targets for material and unit model design. We first analyze two shale gas processing alternatives: the conventional alternative for shale gas processing and the proposed CISTAR alternative. The conventional alternative consists of thermal cracking units and large scale refinement facilities which makes the process energy and capital intensive. CISTAR is trying to use catalytic dehydrogenation and oligomerization in addition to membrane based separation systems to reduce energy requirement and improve scalability of the process. We converted these process flowsheets into mathematical models defining the mass balance across units in python pyomo. After the models were validated using data from our CISTAR collaborators a sensitivity analysis was carried out varying different values for conversion factors in each reactor. As an ongoing work we are exploring more complex unit models by taking into consideration the energy balance of the process, performing a techno-economic analysis including equipment and operating costs as well as the revenue produced by the system, add other shale gas processing alternatives to our model, and finally consider different viable process configurations in order to find the optimal set up.