Experimental and numerical studies of Ca(OH)_(2)/CaO dehydration process in a fixed-bed reactor for thermochemical energy storage

The Ca(OH)_(2)/CaO thermochemical energy storage(TCES)system based on calcium looping has received extensive attention owing to its high energy storage density,prolonged energy storage time,and environmental friendliness.The heat storage process of the Ca(OH)_(2)/CaO TCES system in a mixed heating reactor was evaluated in this study,by employing a combination of direct and indirect heating modes.The dehydration process was studied experimentally,and a numerical model was established and verified based on the experimental results.The dehydration behavior of 500 g of Ca(OH)_(2) powder was investigated in a fixed-bed reactor with mixed heating.The experimental and simulation results indicated that mixed heating causes combined centripetal and horizontal propulsion.Heat input is the main limiting factor in the heat storage process,because the radial advance of the reaction is hindered by the low thermal conductivity of the solid reactant particles.Heat transmission partitions were added to enhance the performance of the reactor.The performance of the modified reactor was compared with that of a conventional reactor.The radial heat transmission partitions in the modified reactor effectively enhance the energy storage rate and reduce the reaction time by 59.5%compared with the reactor without partitions.

Flow characteristics simulation of spiral coil reactor used in the thermochemical energy storage system

According to environmental and energy issues,renewable energy has been vigorously promoted.Now solar power is widely used in many areas but it is limited by the weather conditions and cannot work continuously.Heat storage is a considerable solution for this problem and thermochemical energy storage is the most promising way because of its great energy density and stability.However,this technology is not mature enough to be applied to the industry.The reactor is an important component in the thermochemical energy storage system where the charging and discharging process happens.In this paper,a spiral coil is proposed and used as a reactor in the thermochemical energy storage system.The advantages of the spiral coil include simple structure,small volume,and so on.To investigate the flow characteristics,the simulation was carried out based on energy-minimization multi-scale model(EMMS)and Eulerian two-phase model.CaCO_(3) particles were chosen as the reactants.Particle distribution was shown in the results.The gas initial velocity was set to 2 m·s^(-1),3 m·s^(-1),and 4 m·s^(-1).When the particles flowed in the coil,gravity,centrifugal force and drag force influenced their flow.With the Reynold numbers increasing,centrifugal and drag force got larger.Accumulation phenomenon existed in the coil and results showed with the gas velocity increasing,accumulation moved from the bottom to the outer wall of the coil.Besides,the accumulation phenomenon was stabilized whenφ>720°.Also due to the centrifugal force,a secondary flow formed,which means solid particles moved from the inside wall to the outside wall.This secondary flow could promote turbulence and mixing of particles and gas.In addition,when the particle volume fraction is reduced from 0.2 to 0.1,the accumulation at the bottom of the coil decreases,and the unevenness of the velocity distribution becomes larger.

Biological properties and clinical applications of berberine

Berberine,an isoquinoline alkaloid isolated from the Chinese herb Coptis chinens is and other Berber is plants,has a wide range of pharmacological properties.Berberine can be used to treat many diseases,such as cancer and digestive,metabolic,cardiovascular,and neurological diseases.Berberine has protective capacities in digestive diseases.It can inhibit toxins and bacteria,including Helicobac terpylo riprotect the intestinal epithelial barrier from injury,and ameliorate liver injury.Berberine also inhibits the proliferation of various types of cancer cells and impedes invasion and metastasis.Recent evidence has confirmed that berberine improves the efficacy and safety of chemoradiotherapies.In addition,berberine regulates glycometabolism and lipid metabolism,improves energy expenditure,reduces body weight,and alleviates nonalcoholic fatty liver disease.Berberine also improves cardiovascular hemodynamics,suppresses ischemic arrhythmias,attenuates the development of atherosclerosis,and reduces hypertension.Berberine shows potent neuroprotective effects,including antioxidative,antiapoptotic,and anti-ischemic.Furthermore,berberine exerts protective effects against other diseases.The mechanisms of its functions have been extensively explored,but much remains to be clarified.This article summarizes the main pharmacological actions of berberine and its mechanisms in cancer and digestive,metabolic,cardiovascular,and neurological diseases.