Effect of colloidal particles associated with the liquid bridge in sticking during drying in superheated steam

It is important in the design of a drying system to evaluate the sticking behaviour of the materials being dried. A new approach to the sticking issue is applied in this study by carrying out a sticking test for the liquid associated with the materials under study. It was found that the liquid bridge is responsible for the initial sticking of the materials to the contact surfaces. The colloidal material in this liquid is eventually responsible of building a sticky solid bridge during drying. The glass transition temperature for the Brewers Spent Grain (BSG) particles and the colloidal solution expelled from these particles were tested using Differential Scanning Calorimetric (DSC). However, the chopped BSG particles showed no glass transition temperature; there were an appreciable number of particles stuck to the rotary drum dryer and the sample holders during drying. The colloidal particles in the liquid bridge were filtered and concentrated through evaporation and then analysed by DSC where they showed a glass transition temperature at (-23) and (-33) oC. In addition, the associated liquid thus prepared showed a honey consistency and a sticky touch when concentrated. These two properties are indications that this colloidal material may be responsible for sticking the BSG to the steel surfaces during drying

Selective Electrodialysis for Copper Removal from Brackish Water and Coal Seam Gas Water

This study investigates the removal rate of divalent ions during partial desalination of brackish water using electrodialysis (ED). An experiment was conducted with a benchtop PCCell electrodialysis instrument in batch mode with a non-ion selective membrane. The removal rate of total copper, a valuable plant micronutrient, was analysed. Both copper chloride and copper sulphate removal compared to sodium chloride removal were studied. The copper and the sulphate content in the diluate declined logarithmically with a removal rate of around 98 % for copper in both experiments, and 100 % for sulphate over three hours at a starting temperature of 23 °C. Copper and sulphate were removed faster than sodium chloride at 72 %. The temperature of the diluate increased by 15 % during the three-hour run. The loss of water from the diluate was approximately 10 %, limiting brine production. Modelling indicated that the Mass/Charge ratio of ions could be an indicator of the removal rate of anions, especially if they have, like sulphur, a large effective radius, whereas the Effective Ionic Radius can be an indicator for the removal of cations. The smaller the ionic radius, the faster the removal rate of the cation. This model can be used to customise nutrient concentration in the water end product. The customised water has a potential to be used for fertigation, saving the farmer money by retaining beneficial plant nutrients in the water

The effect of methanol-diesel blended ratio on CI engine performance

In the current work, a comprehensive study on the possibility of using methanol as an alternative fuel for diesel engines was carried out. Methanol was mixed at different ratios with diesel fuel. The mixing ratios of methanol to diesel were 0:100, 10:90, 20:80 and 30:70. The effects of methanol fraction on engine power, torque, brake specific fuel consumption (BSFC), brake thermal efficiency and exhaust temperature were experimentally investigated at variant engine speeds. The engine used to carry out these experiments is a four-stroke four-cylinder diesel engine. The results showed that mixing methanol at different fractions with diesel fuel has a significant effect on the engine performance. The methanol to diesel ratio of 10:90 exhibited the lowest exhaust temperature and achieved an improvement in the output power of approximately 70% compared to the other ratios. Also, the brake thermal efficiency improved at all the mixing ratios used. Furthermore, the BSFC of pure diesel fuel registered a lower value than any other mixing ratio. It has been shown in this research that the addition of 10% methanol to the diesel fuel may have a great impact on the engine performance and the environmen

Effect of Compressed Natural Gas Mixing on the Engine Performance and Emissions

Cleaner air quality is becoming a global concern, thus to improve the fuel and combustion process is vital. In this paper, computational fluid dynamics (CFD) analysis software CFD-ACE is used to investigate the flow behavior of methane and air in a compressed natural gas (CNG)–air mixer to be implemented in a CNG–diesel dual-fuel stationary engine. The effect of the number of mixer holes on the mixture quality was evaluated. The results of the 3D CFD simulation showed that the 8-hole Venturi mixer gave superior performance compared to the 4-hole mixer. Further analysis was carried out on the 8-hole Venturi mixer to investigate the effect of engine speed on the mass flow rate of CNG and the equivalence air to fuel ratio (1/). The second half of the paper presents comparative performance results between a single cylinder research compression ignition (CI) engine fueled with a CNG–diesel system and a conventional CI engine fueled by conventional diesel. The engine was equipped with the simulated 8hole Venturi mixer. The result showed a significant reduction in exhaust gas emission components (NOx, CO and CO) from the CNG–diesel engine compared to the conventional diesel engine, i.e. the reduction rates were on average of 54%, 59% and 31% respectively. The average power output developed by the dual-fuel engine was 10% higher than the diesel over the power curve

Effect of compressed natural gas mixing on the engine performance and emissions

Cleaner air quality is becoming a global concern, thus to improve the fuel and combustion process is vital. In this paper, computational fluid dynamics (CFD) analysis software CFD-ACE is used to investigate the flow behavior of methane and air in a compressed natural gas (CNG)–air mixer to be implemented in a CNG–diesel dual-fuel stationary engine. The effect of the number of mixer holes on the mixture quality was evaluated. The results of the 3D CFD simulation showed that the 8-hole Venturi mixer gave superior performance compared to the 4-hole mixer. Further analysis was carried out on the 8-hole Venturi mixer to investigate the effect of engine speed on the mass flow rate of CNG and the equivalence air to fuel ratio (1/). The second half of the paper presents comparative performance results between a single cylinder research compression ignition (CI) engine fueled with a CNG–diesel system and a conventional CI engine fueled by conventional diesel. The engine was equipped with the simulated 8-hole Venturi mixer. The result showed a significant reduction in exhaust gas emission components (NOx, CO and CO2) from the CNG–diesel engine compared to the conventional diesel engine, i.e. the reduction rates were on average of 54%, 59% and 31% respectively. The average power output developed by the dual-fuel engine was 10% higher than the diesel over the power curve