Recent CACHE Process Design Case Studies
http://cache.org/super-store/cache-process-design-case-studies

Vol. 9: “Conceptual Design of Second Generation Bioethanol Production via 
Gasification of Lignocellulosic Biomass”

Vol. 10: “Conceptual Design of the Supply Chain and Production Facility of 
Lignocellulosic   Bioethanol via Hydrolysis”

Vol. 11: “Conceptual Design of an Aromatics Plant from Shale Gas”

The capstone Senior Process Design Course offers a unique opportunity to 
engage students in the areas of energy and fuel production that are of 
current interest. In this series of three CACHE Design Case Studies 
developed by Carnegie Mellon University, students are required to 
synthesize new processes that use either biomass (vols. 9, 10) or shale gas 
(vol. 11) as raw material. The case studies provide extensive information 
and data for the instructor in order to facilitate the assignment of a 
design project in their design course. Each case study provides background 
for the corresponding topic (bioethanol and shale gas), course 
organization, and complete reports by two design groups that include 
literature review, mass and energy balances, and energy integration and 
economic evaluation.  Slides of the oral presentations by the two design 
groups are also included. Below are the abstracts for each of the case 
studies that can be ordered from: http://cache.org/products-page

CACHE vol 9: Gasification consists of a partial oxidation of carbon based 
raw material to generate syngas. The mixture of CO and hydrogen can be used 
for a wide number of applications, among them the production of second 
generation of bioethanol. The interesting issue of this path is the number 
of alternative process flowsheets to produce ethanol, since there are 
different gasification technologies, reforming modes, CO2 capture methods, 
and different synthesis paths to ethanol, fermentation or mixed alcohol 
synthesis. Separation is another major challenge. This case study provides 
information to guide the students through mass and energy balances and 
process economics using Matlab and Mathcad process models. 

CACHE vol 10:  In this case a different path is used, the biochemical one, 
to produce bioethanol. Furthermore, the transportation and logistics of 
biomass is also considered in this project since it has an impact on the 
plant size. The biochemical route from lignocellulosic raw materials is a 
second generation process for bioethanol that operates at lower pressures 
and temperatures. The pretreatment is followed by hydrolysis, fermentation 
and ethanol dehydration steps. This case study provides information to the 
instructor to guide the students through mass and energy balances and 
process economics. The use of Mathcad for process design is also introduced.

CACHE vol 11: In this case study shale gas and condensates from the wet gas 
(e.g. ethane) are used as raw material instead of more expensive crude oil 
to produce aromatics (benzene, toluene, xylene). One of the interesting 
challenges in the case study is the number of different processes that can 
be synthesized. Students must first screen different alternative chemical 
pathways to decide on the specific process. Furthermore, apart from the use 
of Mathcad or Excel for preliminary process calculations, process 
simulation using ASPEN-PLUS is used for the detailed mass and energy 
balances of the plant, while ASPEN-ENERGY ANALYZER is used for energy 
integration and synthesis of heat exchanger networks.