Catalytic bodies based on MnO2, TiO2 and sepiolite showed an improved behavior for selective reduction of NOx with NH3 at low temperatures. In this work, the influence of Mn %wt and NO2 and/or water vapor presence was assessed. The materials were prepared by wet equilibrium impregnation of the pre-shaped support. All the catalysts exhibited the characteristic diffraction peaks of TiO2-anatase, hexagonal MnO2and anhydrous sepiolite. According to SEM-EDX, MnO2 was preferentially deposited over TiO2.

The optimum nominal content of Mn was 7.5 %wt, what may be related to an appropriate particle dispersion that confers the suitable properties: lower acid strength, and better redox properties with improved reducibility. This catalyst was then evaluated under NO2 and/or H2O presence. NO2 improved the catalytic response and the best result was obtained with 1:1 NO2:NO ratio showing 90 % NOx conversion and 97 % N2 selectivity at very low temperature, 110 °C. A higher amount of NH4NO3 seems to be formed with the increase in the NO2/NO ratio causing a modification of N2 selectivity. Although water presence affected the performance, mainly at low temperatures, the catalyst showed good resistance to water vapor at temperatures above 180 °C maintaining good activity (90 % of NO conversion and 96 % of N2 selectivity). When NO2 was co-added to the feed, a beneficial effect was again observed with 91 % of NOx and 95 % of N2 selectivity converted at 143 °C.

At low temperatures, deactivation has to do with a competitive effect of H2O with NOx towards the adsorption centers, which decreases the concentration of nitrate species adsorbed on the surface. However, the adsorption of ammonia was less affected.

7.5 Mn catalyst is a highly efficient system to work in real conditions, where there is water in gas stream. In this situation, co-feeding NO2 improves activity.

Power tower concentrating solar plants with thermal energy storage will play a key role in the transition to a low carbon scenario, thanks to be a dispatchable renewable energy system. The ternary MgCl2/KCl/NaCl salt appears as one of the most promising due to its lower melting point, higher heat capacity, lower cost and stability up to 800 °C. A cavity-type receiver has been selected because minimizes radiation heat loss at high working temperatures, compared to an external-type receiver, since all commercial selective coatings degrade in air.

Supercritical Brayton power cycle is chosen for the power block because it can surpass 50% efficiency, even when working in dry cooling conditions, and printed circuit heat exchangers are usually recommended due to its ability to support the high pressures. However, plugging/clogging issues arise in their small channels when using molten salts. This paper proposes a novel supercritical CO2 Bayton power cycle whose heat power is supplied through the low pressure side (over 85 bar) allowing the use of shell and tube heat exchangers, achieving a higher compactness and a lower investment. Thus, different options based on the recompression layout with intercooling and reheating have been investigated in both dry and wet cooling scenarios. Reheating is recommended for wet cooling, reaching 54.6% efficiency and an investment of 8662 $/kWe; intercooling with reheating is the best option for dry cooling, reaching 52.6% efficiency and an investment of 8742 $/kWe.

This work proposes a new particle receiver for Concentrating Solar Technology (CST) that employs air and particles as heat transfer fluid (HTF). The novel Linear Particle Solar Receiver (LPSR) is located at the ground level receiving the concentrated solar energy linearly from the top. This receiver is formed by several fluidized beds connected consecutively allowing the horizontal movement of solids and the linear absorption of solar energy. A new solar field is proposed and analyzed to redirect the concentrated solar energy towards the receiver linearly.

The optic analysis of a linear beam-down system is carried out using a ray-tracing software. Then, the performance of a linear particle solar receiver is analyzed considering target temperatures of 200 °C, 400 °C, 600 °C and 800 °C to reproduce CST integration with medium and high temperature process heat, Rankine power generation and supercritical CO2 (sCO2) cycles, respectively. The temperature of the hot streams of air and sand are calculated considering the heat losses from the receiver and the compressor parasitic consumption. The procedure to determine the optimum design is shown studying one line as a function of the target temperature. For instance, a sand mass flow of 1.75 kg/s in a receiver of 0.5 m width and a secondary reflector eccentricity of 0.8, can be heated up to 600 °C in a length of 280 m, showing a solar field efficiency of 40.25% and a receiver thermal efficiency of 80%.