Auxiliary effect of CO2 on pyrolysis of oily sludge.

The efficient recovery and conversion of energy in oily sludge has great prospects. In this article, the main objective is to investigate the impact of the addition of CO2 during the pyrolysis of oily sludge on energy recovery and conversion by thermogravimetric analysis (TGA) and compare the effect with the traditional pyrolysis effect from the perspective of thermal conversion behavior, products composition, and kinetics analysis. The results of the experiment showed that in the CO2 atmosphere, the main weight loss temperature of oily sludge was mainly concentrated in the range of 300-500 °C, which is lower than the reaction temperature range of traditional pyrolysis. The yields of CO and H2 in the products have been greatly improved, and the highest proportion in the gas products can reach 19.29% and 22.38%, respectively. The Ea (activation energy) values of oily sludge were determined to be in the range of 40-120 kJ·mol-1 with the conversion between 0.2 and 0.8 via DAEM, KAS, Starink, and FWO methods, respectively, in which the FWO method has shown the strongest adaptability. The results of this study provide reference values for practical engineering applications.

Simulation study on comprehensive thermal treatment of oil sludge based on Aspen plus.

This article proposed an original comprehensive thermal treatment coupled with gasification and combustion (CGC) of oil sludge (OS), which was designed to produce hydrogen-rich syngas. Based on the experimental results of OS gasification with steam, the combustion characteristics of char from OS gasification were analyzed by thermogravimetric experiments under different heating rates of 10, 20 and 30 °C/min. The combustion process of OS gasification char can be divided into three stages, including water evaporation, volatile combustion and heavy component combustion. The average values of activation energy (E) obtained by Friedman, FWO and Starink methods were 89.98 kJ/mol, 147.61 kJ/mol and 143.09 kJ/mol, respectively. According to OS gasification and OS gasification char combustion experiments, the comprehensive thermal treatment process CGC of OS was simulated by Aspen Plus. The simulation results showed that increasing both gasification temperature and the mass ratio of steam to OS (SOS) could promote the hydrogen production. Considering energy consumption, the recommended OS gasification temperature, SOS and char combustion temperature were 800 ∼ 900 °C, 0.3 ∼ 0.5, and 900 ∼ 1000 °C, respectively, which could ensure full burning of char and reduce the generation of pollutants. The CGC process could reduce CO2 emissions by 44.2% from carbon flow analysis.

Combustion characteristics and kinetic analysis of oil sludge with CaO additive.

Combustion of High-sulfur oil sludge (OS) blended with CaO can significantly reduce the emission of sulfur gas pollutants, but its combustion and kinetic characteristics need to be further studied. TGA experiments showed the combustion characteristics of OS were significantly changed after adding CaO. As reflected by comprehensive combustion index (S), the combustion performance of OS decreased after adding CaO, and significantly improved with the increase of heating rate. The kinetic parameters of the main combustion process of OS with CaO were calculated by the iso-conversion methods of Friedman, FWO, and Starink, respectively. Kinetic analysis results indicated the energy required for OS combustion with CaO first increased and then decreased with deepening of reaction degree. The thermodynamic parameters of ΔH, ΔG and ΔS were determined on the basis of kinetics. The negative ΔH, positive ΔG, and negative ΔS validated the combustion of OS with CaO was an exothermic and nonspontaneous process.

A Comparison of ACQ, AIE and AEE-Based Polymers Loaded on Polyurethane Foams as Sensors for Explosives Detection.

An aggregation-caused quenching (ACQ)-active polymer (PF), an aggregation-induced emission (AIE)-active polymer (PFTPE) and an aggregation-enhanced emission (AEE)-active polymer (PTTPE) were synthesized by tetraphenylethane (TPE), fluorene and thiophene moieties. Polyurethane (PU) foams modified by PF, PFTPE and PTTPE, namely PU-PF, PU-PFTPE and PU-PTTPE, using ultrasonication-assisted method have been prepared. A comparative study of PU-PF, PU-PFTPE and PU-PTTPE for detection explosives had been performed, and significant fluorescence quenching was observed with the introduction of PA solutions. The as-prepared PU-PF, PU-PFTPE and PU-PTTPE sensors exhibited a superior sensitivity for PA solutions with different concentrations. Remarkably, PU-PF gave a quenching efficiency of 96.2%, higher than 93.5% for PU-PFTPE and 86.7% for PU-PTTPE at a PA concentration of 180 µg·mL-1 in methanol, which was attributed to the effective energy transfer from the fluorophore (PF) to the nitro explosive (PA). This suggested that some ACQ polymers, applied to detect explosives, could afford better performances than AIE or AEE polymers through modification of structures and selection of adequate carriers. At the same time, these chemical sensors can be recycled many times.

Structure Design and Characterization of 3D Printing System of Thermal Battery Electrode Ink Film.

In this paper, a 3D printing system for a thermal battery electrode ink film is set up and investigated based on the on-demand microdroplet ejection technology. The optimal structural dimensions of the spray chamber and metal membrane of the micronozzle are determined via simulation analysis. The workflow and functional requirements of the printing system are set up. The printing system includes a pretreatment system, piezoelectric micronozzle, motion control system, piezoelectric drive system, sealing system, and liquid conveying system. Different printing parameters are compared to obtain optimized printing parameters, which can be attributed to the optimal pattern of the film. The feasibility and controllability of 3D printing methods are verified by printing tests. The size and output speed of the droplets can be controlled by adjusting the amplitude and frequency of the driving waveform acting on the piezoelectric actuator. So, the required shape and thickness of the film can be achieved. An ink film in terms of nozzle diameter = 0.6 mm, printing height = 8 mm, wiring width = 1 mm, input voltage = 3 V and square wave signal frequency = 35 Hz can be achieved. The electrochemical performance of thin-film electrodes is crucial in thermal batteries. The voltage of the thermal battery reaches its peak and tends to flatten out at around 100 s when using this printed film. The electrical performance of the thermal batteries using the printed thin films is found to be stable. This stabilized voltage makes it applicable to thermal batteries.

Pyrolysis characteristics and products distribution of petroleum sludges.

Pyrolysis can realise the harmlessness, reduction and resource utilisation of petroleum sludge in a short period. In the present work, a tank bottom sludge (SSOS) and a landing sludge (SLOS) from Shengli Oilfield were used for experimental research. Thermogravimetric testing is used to initially determine the optimal range of pyrolysis temperature. Pyrolysis experiments were performed in a tube furnace reactor. Pyrolysis products were collected and analysed separately. The char yield of SSOS and SLOS were 50% and 70%, respectively. Although there are differences in the oil content of the two types of petroleum sludge, the oil yield remained nearly the same, which were both between 7% and 8%. As the pyrolysis temperature was raised to 500°C, the yield of each product did not change greatly while their composition had obvious changes. High temperature is more conducive to the production of small molecule products. Result showed that pyrolysis treatment of petroleum sludge can effectively recover energy materials in the form of pyrolysis gas and oil. The heating value of char is lower than that of petroleum sludge, which means that char is not suitable for direct use as fuel. Pyrolysis treatment also showed good curing effect on Cr, which reached 85%. However, the solidification effect decreased as pyrolysis temperature increasing. It is necessary to pay attention to the heavy metal contained in char as soil improver. The rich surface structure of char provides evidence to produce high value-added carbon materials.

Experimental study on gasification of oil sludge with steam and its char characteristic.

Hydrogen can be prepared by oil sludge (OS) gasification with steam, which is of great significance for industrial hazardous waste treatment and resource conservation. The gasification performance was studied by a tube furnace reactor. The OS gasification was carried out at different temperatures (600, 700, 800 and 900 °C) and with different steam to OS ratio (SOS) (0.1:1, 0.3:1, 0.5:1). During the gasification process, hydrogen production first increased and then decreased, and hydrogen production was faster in 5-15 min. The yield of hydrogen of OS gasification reached the maximum when the SOS was 0.3:1 at 800 °C. The highest hydrogen yield per unit mass OS was 48.50 mL min-1 g-1. After gasification, the char yield was high, generally more than 50%. It was necessary to treat the char and incineration was an effective solution for low carbon fuels. Thus particle size distribution, incineration thermogravimetric analysis and heavy metal leaching concentrations analysis were carried out. The results showed that the average particle size of char ranged from 85 to 120 µm. The char incineration process could be divided into three stages: water evaporation, the precipitation and combustion of volatiles, and the combustion of fixed carbon and heavy components. After OS gasification at 800 °C, the leaching concentrations of typical heavy metals (As, Cr, Cu, Ni, Pb and Zn) were all up to the standard. Therefore, OS gasification combined with char incineration was an effective approach for the utilization of solid waste, which can recover hydrogen energy and reduce environmental risks.

Pyrolysis characteristics and kinetics analysis of oil sludge with CaO additive.

In the process of exploitation, transportation and refining of high-sulfur crude oil, a large number of oil sludge (OS) with high sulfur content is produced. Pyrolysis has been proved to be an effective method for OS disposal, but for solid waste with high sulfur content, lots of sulfur-containing gases will be released during thermal disposal. The addition of calcium oxide in pyrolysis process is an economical and effective way to capture sulfur-containing gases. In order to understand the pyrolysis process of OS with CaO, a thermogravimetric analyser was used to conduct pyrolysis experiments of OS with different Ca/S molar ratios (0, 1, 2 and 3) at different heating rates (10°C/min, 20°C/min, 30°C/min and 40°C/min). The results showed that with the increase of CaO addition the derivative thermogravimetric curves showed a gentle trend. In addition, new weight loss peaks were occurred at 700-900°C and after 1100°C, which were the decomposition of calcium carbonate and calcium sulfate, respectively. The kinetic parameters were solved by Friedman, FWO, and Starink methods, and the results were similar, with an average activation energies (E) value of 214 kJ/mol. The change trend of the activation energy was followed by an increase and then a decrease corresponding to the change of energy demand for the reaction. The calculated average values of ΔH, ΔG and ΔS were about 207, 447 and -0.3250 kJ/mol, respectively. When the conversion rate was 0.5, the thermodynamic parameters reached their maximum values.