• Energy Research

Abstract The augmented concerns towards greenhouse emissions have stimulated the innovative technologies to reduce the carbon footprints and lessen the usage of fossil fuel by replacing them with biomass. Wheat straw is a biowaste and has a great potential for energy-production. However, the inorganic contents in the wheat straw cause operational problems such as low heat transfer and ash-deposition in combustion chamber leading to high maintenance requirements. Demineralization of wheat straw with various basic and acidic leaching reagents (NaOH, HCl, HNO3) was investigated in this study. The concentrations of leachants was varied from 0.6, 0.4 and 0.2M to study their effect on physical, chemical, thermal and kinetic behavior of the biomass. The 0.6 M HCl solution reduced the maximum ash content up to 92.71 % and raised the heating value to 3.98 % than raw wheat straw. The kinetic study of the samples treated with 0.6M HCl demonstrated the superior ignition and the activation-energy than other samples. On other hand NaOH damaged the structure of the wheat straw and had adverse effects on their physical and chemical properties. The results of the current study suggested that HCl treated wheat straw can provide a cost effective and eco-friendly solution for energy generation.

Abstract The augmented concerns towards greenhouse emissions have stimulated the innovative technologies to reduce the carbon footprints and lessen the usage of fossil fuel by replacing them with biomass. Wheat straw is a biowaste and has a great potential for energy-production. However, the inorganic contents in the wheat straw cause operational problems such as low heat transfer and ash-deposition in combustion chamber leading to high maintenance requirements. Demineralization of wheat straw with various basic and acidic leaching reagents (NaOH, HCl, HNO3) was investigated in this study. The concentrations of leachants was varied from 0.6, 0.4 and 0.2M to study their effect on physical, chemical, thermal and kinetic behavior of the biomass. The 0.6 M HCl solution reduced the maximum ash content up to 92.71 % and raised the heating value to 3.98 % than raw wheat straw. The kinetic study of the samples treated with 0.6M HCl demonstrated the superior ignition and the activation-energy than other samples. On other hand NaOH damaged the structure of the wheat straw and had adverse effects on their physical and chemical properties. The results of the current study suggested that HCl treated wheat straw can provide a cost effective and eco-friendly solution for energy generation.

Abstract Conversion of sewage sludge into fuel was investigated using a catalyst- and external hydrogen-free supercritical fluid route. When dried sewage sludge was treated in supercritical ethanol, an extremely high bio-oil yield of 87.8 wt% and a remarkable higher heating value (HHV) of 34.6 MJ kg −1 were obtained. The possibility of using non-dried sewage sludge as a fuel source was tested using various alcohol–water mixtures; the presence of water resulted in an almost complete (96%) conversion and high HHVs of 36.8 and 37.3 MJ kg −1 for methanol–water (3:7, v/v) and ethanol–water (3:7, v/v) mixtures, respectively. The main chemical compounds in the bio-oils were found to be esters and nitrogenated species. Plausible reaction mechanisms for sewage sludge conversion in each supercritical fluid are discussed.

Abstract Conversion of sewage sludge into fuel was investigated using a catalyst- and external hydrogen-free supercritical fluid route. When dried sewage sludge was treated in supercritical ethanol, an extremely high bio-oil yield of 87.8 wt% and a remarkable higher heating value (HHV) of 34.6 MJ kg −1 were obtained. The possibility of using non-dried sewage sludge as a fuel source was tested using various alcohol–water mixtures; the presence of water resulted in an almost complete (96%) conversion and high HHVs of 36.8 and 37.3 MJ kg −1 for methanol–water (3:7, v/v) and ethanol–water (3:7, v/v) mixtures, respectively. The main chemical compounds in the bio-oils were found to be esters and nitrogenated species. Plausible reaction mechanisms for sewage sludge conversion in each supercritical fluid are discussed.

The use of formic acid leads to the complete decomposition of alkali lignin and affords high-yield aromatic monomers, while at the same time suppress consumption of solvent used for the lignin conversion.

The use of formic acid leads to the complete decomposition of alkali lignin and affords high-yield aromatic monomers, while at the same time suppress consumption of solvent used for the lignin conversion.

Increased energy demand in recent decades has resulted in both an energy crisis and carbon emissions. As a result, the development of cleaner fuels has been under the research spotlight. Low-rank coals are geographically dispersed, abundant, and cheap but are not utilized in conventional processes. Syngas can be produced from coal-using gasification which can be used in various chemical engineering applications. In this study, the process model for syngas production from low-rank coal is developed and the effects of various process parameters on syngas composition are evaluated, followed by a technical and economic evaluation. The syngas production rate for the low-rank coal has been evaluated as 25.5 kg/s, and the contribution to H2 and CO production is estimated as 1.59 kg/s and 23.93 kg/s, respectively. The overall syngas production and energy consumed in the process was evaluated as 27.68 kg/GJ, and the CO2 specific emissions were calculated as 0.20 (mol basis) for each unit of syngas production. The results revealed that the syngas production efficiency for low-rank coals can be as high as 50.86%. Furthermore, the economic analysis revealed that the investment and minimum selling prices per tonne of syngas production are EUR 163.92 and EUR 180.31, respectively.

Increased energy demand in recent decades has resulted in both an energy crisis and carbon emissions. As a result, the development of cleaner fuels has been under the research spotlight. Low-rank coals are geographically dispersed, abundant, and cheap but are not utilized in conventional processes. Syngas can be produced from coal-using gasification which can be used in various chemical engineering applications. In this study, the process model for syngas production from low-rank coal is developed and the effects of various process parameters on syngas composition are evaluated, followed by a technical and economic evaluation. The syngas production rate for the low-rank coal has been evaluated as 25.5 kg/s, and the contribution to H2 and CO production is estimated as 1.59 kg/s and 23.93 kg/s, respectively. The overall syngas production and energy consumed in the process was evaluated as 27.68 kg/GJ, and the CO2 specific emissions were calculated as 0.20 (mol basis) for each unit of syngas production. The results revealed that the syngas production efficiency for low-rank coals can be as high as 50.86%. Furthermore, the economic analysis revealed that the investment and minimum selling prices per tonne of syngas production are EUR 163.92 and EUR 180.31, respectively.