The contaminants of acid gas feed to the Claus process plants such as benzene, toluene, ethylbenzene, and xylene (BTEX) increase the operational cost through catalyst deactivation and high fuel gas consumption and impact the sulfur recovery efficiency and the emission of toxic gases (such as CO and SO 2 ). In this study, a detailed and validated reaction mechanism for Claus feed combustion is utilized to simulate the Claus process plant by integrating Chemkin Pro and Aspen HYSYS software. The effect of oxygen enrichment of air on sulfur recovery, BTEX destruction, toxic gas emissions, and fuel gas consumption is studied. Upon increasing the oxygen concentration in air, BTEX concentration decreased substantially due to their enhanced oxidation by SO 2 and O 2 . An increase in oxygen concentration resulted in (a) increased SO 2 emission and decreased CO 2 emission from the incinerator, and (b) decreased fuel gas consumption in the incinerator. Interestingly, CO emission increased with increase in oxygen concentration in air as the furnace temperature increased up to 1350 °C, but it decreased with the further increase in the furnace temperature at higher oxygen concentrations. The reaction path analysis is presented to understand this decrease in CO emissions at high oxygen concentrations. The results demonstrate that a high oxygen concentration in air can be utilized to decrease fuel gas consumption and CO and CO 2 emissions in the Claus process. The oxygen concentration, required to minimize the emission of aromatics, SO 2 , CO, and CO 2 , was dependent on the feed composition, and the developed reaction mechanism can assist in optimizing the oxygen enrichment level required for a given feed in a Claus process plant.

Ammonia and aromatics such as benzene, toluene, and xylene are typically found in acid gas and sour water stripper gas in oil and gas processing plants and gasification facilities. This gas is often processed in sulfur recovery units (SRUs) to recover marketable sulfur and thermal energy. Ammonia must be completely oxidized at high temperatures in the furnace to prevent the plugging of catalytic reactors and the corrosion of downstream equipment in the SRU. In this paper, a detailed reaction mechanism is presented to capture the chemistry of ammonia destruction in the presence of several chemically active species of acid gas combustion in the thermal section of SRUs. The mechanism is validated with different sets of experimental data from lab-scale and industrial plant studies. The reaction mechanism is utilized to simulate the furnace and the waste heat boiler (WHB) of SRUs in CHEMKIN PRO software. Through the furnace and WHB simulations, the most suitable operating conditions of the furnace that could lead to an effective destruction of ammonia in the furnace is investigated, and the dominant reaction pathways involved in the oxidation process are identified. With increasing feed temperature and oxygen concentration in air, the ammonia concentration was found to decrease substantially down to an acceptable limit of <150 ppm at the exit of the thermal section of SRUs. The decrease in NH 3 occurred because of its enhanced oxidation by several oxidants (OH, SO, and O 2 ) at high temperatures above 1300 °C, though it also led to a decrease in sulfur recovery efficiency and an increase in CO production at the exit of the thermal section. This indicates the need for optimized furnace parameters that could lead to a reasonable trade-off between ammonia destruction and CO emissions from the SRU. The developed reaction mechanism provides a way to obtain optimized SRU parameters to achieve ammonia destruction, enhanced catalyst life, and reduced emission of harmful gases (CO and SO 2 ).

Digital Rock Physics (DRP) has significantly evolved in the last few years and added invaluable contributions in improving core characterization and in providing high quality advanced SCAL measurements, emphasized through various studies/papers (SCA-2012–03 Kalam et al). This paper represents a unique DRP SCAL study that includes primary drainage capillary pressure (Pc) as part of Swi establishment and relative permeability (Kr) measurements done on four whole core (WC) samples from two different carbonate formations with a stylolite layer in between. The aim of the study was to evaluate how DRP results would compare with physical SCAL measurements done – on the same WC samples as a composite, as well as on plug samples from the same formations/layers – in a leading international core analysis lab in USA. The DRP results were up-scaled to the individual WC level and compared with the SCAL results from the corresponding layers. The DRP technology in this study also provided the capability of up-scaling the results to the WC composite which was used by the lab to assess the effect of the stylolite layer on the water flood. The comparison showed excellent matches between the physical and DRP-derived Pc and Kr data. The paper outlines the DRP methods used to determine the SCAL properties of the three formations. The laboratory measurements of SCAL properties took six years while the DRP work that followed blindly (without any knowledge of the laboratory results) was completed in six months. This demonstrates the effectiveness of the DRP technology in providing high quality SCAL data in a timely fashion regardless of sample size. Impact of possible wettability changes and sensitivities on one of the WC composite constituent component was also easily established unlike the high risk laboratory tests. This is the first water-oil displacement validation study results on reservoir whole cores of four inch diameter at full reservoir conditions using DRP.