Effect of Molecular Structure of C₁₀ Hydrocarbons on Production of Light Olefins in Catalytic Cracking

The effect of the molecular structure of feedstock on the cracking reaction of C10 hydrocarbons to ethylene and propylene over H-ZSM-5 zeolite was investigated. To better compare the effect of decane on the production of light olefins, the thermal cracking and catalytic cracking performance of decane were first investigated. As a comparison, the thermal cracking and catalytic cracking of decane were studied by cracking over quartz sand and H-ZSM-5. Compared with the thermal cracking reaction over quartz sand, the catalytic cracking reaction of decane over H-ZSM-5 has a significantly higher conversion and light olefins selectivity, especially when the reaction temperature was lower than 600 °C. On this basis, the catalytic cracking reactions of decane and decene over H-ZSM-5 were further compared. It was found that decene with a double bond structure had high reactivity over H-ZSM-5 and was almost completely converted, and the product was mainly olefin. Compared with decane as feedstock, it has a lower methane yield and higher selectivity of light olefins. Therefore, decene was more suitable for the production of light olefins than decane. To this end, we designed a new light olefin production process. Through olefin cracking, the yield of light olefins in the product can be effectively improved, and the proportion of different light olefins such as ethylene, propylene and butene can be flexibly adjusted

Wireless power transmission for remote-relay-nodes-aided smart metering

Wireless power transmission is a promising technique to provide continuous power supply for the limited capacitance of smart meters (SMs) with short distance communication. In this study, the authors propose a remote-relay-nodes (RRNs)-aided wireless SM system, where several geographically separated RRNs are connected to a concentrator or an acquire terminal via radio-over-fibre. A RRN selection scheme is employed in the wireless power transfer phase. With the energy harvested, the SM can report special or urgent events in the wireless information transfer phase. The asymptotic reporting probability and reliability of smart metering are derived in terms of close form over fading channels. Numerical results are provided to verify the theoretical analysis. The optimal deployment of RRNs can be also efficiently obtained by averaging the locations of a SM in the network

High-Temperature Cracking of Pentene to Ethylene and Propylene over H-ZSM-5 Zeolites: Effect of Reaction Conditions and Mechanistic Insights

The effects of reaction conditions on the yield of ethylene and propylene from pentene cracking were investigated in a fixed-bed reactor at 500–750 °C and for a weight hourly space velocity (WHSV) of 15–83 h−1. The total yield of ethylene and propylene reached a maximum (67.8 wt%) at 700 °C and 57 h−1. In order to explore the reaction mechanism at high temperatures, a thermal/catalytic cracking proportion model was established. It was found that the proportion of pentene feed chemically adsorbed with the acid sites and cracked through catalytic cracking was above 88.4%, even at 750 °C. Ethylene and propylene in the products were mainly derived from catalytic cracking rather than thermal cracking at 650–750 °C. In addition, the suitable reaction network for pentene catalytic cracking was deduced and estimated. The results showed that the monomolecular cracking proportion increased from 1% at 500 °C to 95% at 750 °C. The high selectivity of ethylene and propylene at high temperatures was mainly due to the intensification of the monomolecular cracking reaction. After 20 times of regeneration, the acidity and pore structure of the zeolite had hardly changed, and the conversion of pentene remained above 80% at 650 °C

Calibration of a Micromegas-based Gaseous Time Projection Chamber Using Cosmic Ray Muons

We report the calibration of a gaseous Time Projection Chamber based on Micromegas charge readout modules with cosmic ray muons, utilizing their penetrating power and relatively uniform energy deposition per unit length. Muon events were selected through track reconstruction to characterize detector performances, such as the drift velocity, electron lifetime, detector gain, and electric field distortion. The evolution of detector performances with gas purities and electric drift fields over a 50-day data-taking cycle was measured by the muon calibration method. For instance, the drift velocity degraded with gas impurities from ${3.40\pm 0.07 ~ cm/\mu s}$ to ${3.06\pm 0.06 ~ cm/\mu s}$, and then recovered with gas purification. A ${^{137}Cs}$ calibration source was also placed inside the detector as a reference for muon calibrations