biomass gasification, Alternative energy

The present study investigates the integrated catalytic adsorption (ICA) steam gasification of palm kernel shell for hydrogen production in a pilot scale atmospheric fluidized bed gasifier. The biomass steam gasification is performed in the presence of an adsorbent and a catalyst in the system. The effect of adsorbent to biomass (A/B)  ratio (0.5-1.5 wt/wt), fluidization velocity (0.15-0.26 m/s) and biomass particle size (0.355-2.0 mm) are studied at temperature of 675 °C, steam to biomass (S/B) ratio of 2.0 (wt/wt) and biomass to catalyst ratio of 0.1 (wt/wt). Hydrogen composition and yield, total gas yield, and lower product gas heating values (LHVgas) increases with increasing A/B ratio, while particle size has no significant effect on hydrogen composition and yield, total gas and char yield, gasification and carbon conversion efficiency. However, gas heating values increased with increasing biomass particle size which is due to presence of high methane content in product gas. Meanwhile, medium fluidization velocity (0.21 m/s) favoured hydrogen composition and yield. The results showed that the maximum hydrogen composition and yield of 84.62 vol% and 91.11 g H2/kg biomass, respectively, are observed at A/B ratio of 1.5, S/B ratio of 2.0, catalyst to biomass ratio of 0.1 and temperature of 675 °C. The product gas heating values are observed in the range of 10.92-17.02 MJ/Nm3. Gasification and carbon conversion efficiency are observed in the range of 25.66-42.95 % and 20.61-41.95 %, respectively. These lower efficiencies are due to significant CO2 capturing using in-situ CO2 adsorption in pilot scale fluidized bed gasification system. The comparative study with literature shows that the combination of adsorbent and catalyst produces better results in terms of hydrogen composition and gas heating values compared to that of biomass steam catalytic gasification and steam gasification with in-situ CO2 adsorbent.

District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand-outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations. Abstract Presently, the crisis of energy has become a growing concern all over the world and a serious barrier for the developing nations. Conversely, the resources of fossil fuels are limited and depleting due to the exploration and higher production activities around the glove. The impact of fossil fuels exploration has become a serious threat for naturalism and creates environmental hazardous accidents. However, the demand for energy in Bangladesh is increasing day by day and fossil fuel reserves continue the countries demand almost only 50 years. So, it is the high time to utilize its natural biomass resources to fulfill energy demand. The climate condition and waste generation rate of Bangladesh is key factors for biomass energy production. Nowadays the Bangladeshi government has made an agenda "waste to electricity" thus the utilization of biomass resources has become a blessing for the static economic growth in the nation. Recently Bangladeshi government has made an extra effort for the commercialization and marketable of biomass energy engendering and production in the country. This paper explored the potential of biomass energy as a sustainable energy source and their future implementation challenges in Bangladesh.

Bio-hydrogen renowned as a future potential hydrogen source and studies were devoted in developing the efficient way to
obtain the hydrogen. Biomass gasification of Azadirachta excelsawood was carried out with addition of naturally
derived CaO catalyst using temperature-programmed gasification (TPG) technique. The reaction (TPG) was performed at
50–1000


Cin5%O2/He with flow rate 10 ml/min, and the product gas evolution (H2,CH4,COandCO2) was detected by
online mass spectrometer. The waste eggshell was chosen as a natural source of CaO, and the effect of catalyst loading was
investigated in this study. All the fresh and used catalysts were characterized, and the physicochemical changes of the eggshell
were observed through scanning electron microscopy, X-rayfluorescence and X-ray diffraction techniques. Hydrogen yield
were increased along with the catalyst loading (20%, 40% and 60%) from 57 to 73%, respectively, compared to the reaction
without catalyst. The additions of waste eggshell enhanced the catalytic activity and suppressed CO2production through
CaO absorption property which induced the water gas shift reaction that promotes H2 production at lower temperature.

Gasification Systems Overview
Gasification converts any carbon-containing material into synthesis gas, composed primarily of carbon monoxide and hydrogen (referred to as syngas)

Syngas can be used as a fuel to generate electricity or steam, as a basic chemical building block for a large number of uses in the petrochemical and refining industries, and for the production of hydrogen

Gasification adds value to low- or negative-value feedstocks by converting them to marketable fuels and products