| This dissertation presents novel realizations for the synthesis of process flowsheets that are beneficial to the environment through: clean and efficient production of hydrogen; optimization of heat exchange networks, power generating networks, and cooling networks; identification of optimal equilibrium reaction operating conditions for natural gas reforming in the presence of metal oxide sorbents. The presented implementations can be generalized to set a basis for the engineering of industrial chemical process designs with minimal energy waste and minimal emissions.;First, novel environmentally friendly process flowsheets that co-produce hydrogen and formic acid from natural gas, without emitting any carbon dioxide, are presented. The principal technologies employed in the process networks include combustion, steam-methane reforming (SMR), dry reforming, pressure-swing adsorption, and formic acid production (from CO2 and H7, and methyl formate hydrolysis). Thermodynamic analysis provides operating limits for the proposed process, and the use of reaction clusters leads to the synthesis of feasible process flowsheets. Heat and power integration studies show these flowsheets to be energetically self-sufficient, through the use of heat exchanger, heat engine and heat pump subnetworks.;The structure of the identified subnetworks can be automatically synthesized with the Infinite DimEnsionAl State-space (IDEAS) conceptual framework. Three case studies are presented: a heat exchange network consisting of two cold streams, two hot streams, one hot utility and one cold utility; a plant generating power through a Rankine cycle, consisting of ammonia as cycle fluid, high temperature ethylene glycol as heat source (containing heat absorbed from the sun), and cooling water; a vapor-compression refrigeration cycle utilizing carbon dioxide as cycle fluid and ambient air as heating and cooling agent. The three cases are compared to a reference point on total annualized cost (TAC) and efficiency bases, showing to approach or surpass the reference point.;In addition to structural optimization of process flowsheets, we can enhance the performance of a process flowsheet by improving individual components therein. In the case of hydrogen production, large energy needs are required by the steam methane reforming reaction. The hydrogen production and its purification can be improved by increasing the conversion of hydrogen in this reaction, while adsorbing carbon dioxide and carbon monoxide into a bed containing a solid metal oxide. The equilibrium characteristics of this process are quantified through the Gibbs free energy minimization approach. Two metal oxides are studied, calcium oxide and magnesium oxide, the addition of the former in the reaction shows improvement in the hydrogen conversion, while the latter has insignificant positive effects in the reaction. |
