Naturally occurring radioactive materials (NORM) encountered in oil and gas
exploration, development and production operations originates in subsurface
formations, which may contain radioactive materials such as uranium, thorium,
potassium and their decay products, radium 226 and radium 228. NORM can be
brought to the surface in the formation water that is produced in conjunction
with oil and gas, which could pose a radiation safety hazard. Natural gas
fracking in the Marcellus shale brings out NORM to the surface in a
concentrated form. The levels of NORM in flowback
water are often initially low because more hydraulic fracturing fluid is being
pumped out. However, NORM levels have the potential to climb over time as the
fluid being extracted begins to contain proportionally greater amounts of
brine. Therefore, the majority of Marcellus produced water contains significant
levels of NORM. Current reports ascertain that there is no commercial product
on the market that is capable of selectively removing NORM from concentrated
produced and flowback waters.
The goal of this project is to develop a screening protocol for
an existing high-throughput adsorbents and to develop new adsorbents for
NORM removal that are both cost effective and environmentally benign. Computer
aided molecular design (CAMD) technique is implimented
to develop adsorbents for NORM removal. CAMD is generally the reverse use of
the group contribution method (GCM) that is used to generate molecules having
desirable properties. GCM has been used to predict state properties like
selectivity, relative volatility, surface tension, density, viscosity, and
reactivity. We will develop new group contribution methods for important
properties of adsorbents based on thermodynamics. The GCM along with CAMD based
optimization methods will identify potential groups of environmentally benign
adsorbents. To perform the optimization, multi-agent optimization algorithm is
implemented.