Sponsor(s): Chemical Industry and Engineering Society of China; Chemical Industry Press
12 issues per year
Current Issue: Issue 07, 2020
CIESC Journal is supervised by China Association for Science and Technology and sponsored by Chemical Industry and Engineering Society of China, and Chemical Industry Press. The predecessor of the journal is Journal of China Chemical Industry Association launched in 1923 and Chemical Engineering launched in 1934. The journal aims at reflecting the major achievements of fundamental research and application in chemical and engineering and other related fields, as well as new technologies and methods. Its scope covers thermodynamics, separation engineering, process system engineering, bio-engineering and chemical engineering, energy and environmental engineering, material chemical engineering and nanotechnology, and modern chemical technology. The journal is included in CA, JST, Pж(AJ), EI, CSCD.
Director: Zhao Yingli
Preparation and thermal storage performance of novel composite sorbent with activated alumina matrix
CIESC Journal,2020,Vol 71,No. 07
A new type of composite sorbent based on activated alumina (AA) and CaCl 2 as a hygroscopic salt was developed. It can be used in thermochemical adsorption heat storage systems with water as the sorbent, and its internal structure, adsorption performance and heat storage performance were studied. The samples with different salt content were fabricated to store low-temperature thermal heat by impregnation methods. The morphologies records, sorption kinetics and thermal energy storage performance of AA/CaCl 2 composite sorbents were investigated. The maximum salt content of the solution leakage phenomenon was determined. Sorption kinetics and equilibrium sorption capacity under conditions of 30 °C and multiple relative humidity were studied by utilizing a constant temperature and humidity chamber. The influences of salt content and relative humidity on the sorption performance of AA/CaCl 2 composite sorbent were studied. Results showed the sorption capacity of AA/CaCl 2 composite sorbent increased with increasing salt content and relative humidity. The specific surface area and pore volume were measured by an automatic specific surface area and porosity analyzer. The energy storage density was measured by a simultaneous thermal analyzer. The sample with the highest salt content had the best energy storage performance with 0.51 kW·h/kg mass energy storage density and 610.2 kW·h/m 3 volumetric energy storage density. As a consequence, AA/CaCl 2 composite sorbent is a promising sorbent in the field of chemisorption thermal energy storage.
Analysis of flow and heat transfer characteristics in external heat extractor of gas-solid fluidized bed
CIESC Journal,2020,Vol 71,No. 07
The external heat extractor is one of the key equipment to maintain the heat balance of the catalytic cracking reaction system and keep the device running smoothly. It can process feed oils into products with higher value, such as gasoline, diesel, and olefins. The catalytic cracking reaction belongs to a parallel series reaction, and its desired products are the reaction intermediate. Meanwhile, a lot of heat is absorbed during reaction. The heat is mainly provided by coke-burning regeneration of the catalysts in the regenerator. When heavy oils are processed, the carbon amount on the catalysts will be increased, which can generate extra heat during the coke-burning regeneration of the catalysts. A fluidized bed with external catalyst cooler can take the extra heat away to control the reaction temperature effectively and keep the heat balance between reaction and regeneration. The downflow external catalyst coolers have been widely used due to their high heat load and flexible adjustment. Both optimal design and effective control of downflow external coolers in industrial applications require a deep understanding of gas-solid flow characteristics, heat transfer characteristics, and their correlation. Therefore, a pilot-scale cold-mode experimental setup was built to investigate the effect of superficial gas velocity and solid mass flux on heat transfer, solid holdup, and bubble frequency. The results showed that the instantaneous heat transfer coefficient presented the characteristics of low frequency and high amplitude as well as high frequency and low amplitude, and the former played a dominant role. The fluctuation periods of instantaneous heat transfer coefficient and instantaneous local solid holdup were both 25 s, which indicated that the heat transfer process between bed and heat transfer tube was directly related to the local solid holdup. Increasing superficial gas velocity can reduce local solid holdup, increase local bubble frequency, and enhance the heat transfer between bed and heat transfer surface. Moreover, local solid holdup and local bubble frequency were increased with solid mass flux. Heat transfer coefficient was decreased with solid mass flux at ug = 0.1 m/s, while increased with solid mass flux at ug ≥ 0.4 m/s. Influence of gas-solid flow characteristics on heat transfer characteristics was various under different flow patterns of fluidized beds. In the bubbling bed flow pattern, local bubble frequency near the heat transfer tubes had a great influence on the heat transfer process, because high local solid holdup impeded the renewal of particles on the heat exchange surface. In the turbulent bed flow pattern, heat transfer coefficient was increased with local solid holdup and bubble frequency. Empirical correlations for predicting heat transfer coefficient at different flow patterns were built on the basis of operation conditions and gas-solid flow characteristics. Their mean relative deviations between predicted value and experimental value were 6.9% and 1.3%, respectively.