The STEP 10 MWe sCO2 Pilot Demonstration Status Update

The Gas Technology Institute (GTI®), Southwest Research Institute® (SwRI®) and General Electric Global Research (GEGR) are executing the “STEP” [Supercritical Transformational Electric Power] project, to design, construct, commission, and operate an integrated and reconfigurable 10 MWe sCO2 [supercritical CO2] pilot plant test facility. The $122* million project is funded $84 million by the US DOE’s National Energy Technology Laboratory (NETL Award Number DE-FE0028979) and $38* million (*including building investment) by the team members, component suppliers and others interested in sCO2 technology. This paper provides an update on the project’s progress. The pilot facility is currently under construction at SwRI’s San Antonio, Texas, USA campus. Now well into Phase 2, a ground-breaking was held in October of 2018, and civil work and the construction of a dedicated 22,000 ft2 building is complete. Most major equipment is in fabrication or delivered to site. Efforts have already provided valuable project learnings for technology commercialization. This project is a significant step toward sCO2 cycle based power generation commercialization and is informing the performance, operability, and scale-up to commercial plants.

An experimental study on head loss characteristics of pipe bends for flow of coal–water slurry at high solid concentration

Bending of pipes is a major problem facing the engineers during the construction of a long pipeline for transporting coal–water slurry. However, the use of 90° bends in slurry transportation is restricted because it causes high head loss, and so very high pumping power is required to overcome this resistance. In this context, the present study is carried out to reduce the head loss for the flow of coal–water suspension across 90° pipe bends by varying bend geometry. Rheological experiments were performed to study flow characteristics of coal–water suspension with/without the additive. Coal–water slurry exhibits Newtonian behavior at a solid concentration of 30 wt% and pseudoplastic flow nature at concentration above 30%. Head loss experiments were carried out on a pilot plant test loop for a solid concentration of 30.27–61.56% with flow velocity ranging from 2 to 5 m/s. The r/ D ratio for the pipe bend varied within the range of 1.5–2.5. The present study reveals that the head loss across pipe bends increased as solid concentration and flow velocity was increased. The optimum r/ D ratio value for a minimum head loss was found to be 2.0. Also, significant decreases in apparent viscosity and head loss were perceived with the addition of a small amount of sulfonic acid. Power required to pump coal–water slurry was decreased by 15.93% with the use of an additive. A correlation for the head loss in terms of solid concentration, flow velocity, and r/ D ratio was also developed.

The application of an efficient modified decolorizer in coagulation treatment of high color reclaimed water

High color concentrations in inflows at reclaimed water treatment plants are typically considered as emergency situations, which must be solved using an appropriate decolorizing process. Using the decoloration mechanism of a modified dicyandiamide-formaldehyde polymer (DFP), a urea-formaldehyde polymer and a melamine-formaldehyde polymer (MFP) were prepared with ammonium chloride and ammonium sulfate as the modifiers. An orthogonal experiment indicated that a modified urea-formaldehyde polymer had no effect on decolorization; however, the MFP modified by ammonium chloride in number 16 (MMFP-C16), the DFP modified by ammonium chloride in number 9 (MDFP-C9) and modified by ammonium sulfate in number 6 (MDFP-S6) were successful. The removal rates were above 50% in acidic and reactive dye reclaimed water. Fourier transform infrared spectroscopy was used to microscopically analyze the differences in decolorization effect among the polymers. The effect of pH on decolorization was analyzed. Compared to the MDFP-C9 and MDFP-S6, the MMFP-C16 was not sensitive to changes in conditions. The pilot plant test proved that the three optimal decolorizers also had a good decolorizing effect, and MMFP-C16 was better both at decolorizing and floc sedimentation. Thus, the latter can be considered as an efficient modified decolorizer for rapid treatment of high color reclaimed water.