Abstract. Presently, biomass is mostly utilized as co-fuel in coal combustion in view of energy diversification and emission reduction. However, since the coal content of bio-briquettes is high (up to 80% in this study), gas emissions such as those of SO x still occur. Therefore, the introduction of SO 2 adsorbent is common in coal briquette or bio-briquette combustion. A calcium-based material is usually used for this goal. The aim of this study was to observe the effects of desulfurization temperature and Ca/S ratio (Ca = calcium content in adsorbent; S = sulfur content in coal and biomass) on desulfurization efficiency and kinetics. The ratio of coal to biomass (palm kernel shell/PKS) was fixed at 90:10 (wt/wt) and the ratios of Ca to S were varied at 1:1, 1.25:1, 1.5:1, 1.75:1 and 2:1. The mixtures of coal, PKS and adsorbent were briquetted at a molding pressure of 6 ton/cm 2 with Jatropha curcas seeds and starch mixture as binding agents. Desulfurization was performed within a temperature range of 300 to 500°C for 720 seconds at an airflow rate of 1.2 L/min. The results showed that the highest desulfurization efficiency (90.6%) was associated with the Ca/S ratio of 2:1 and temperature of 400°C. Moreover, the highest reaction rate constant of desulfurization was 0.280 min -1 .

One of the technologies that can be used to meet energy needs is biomass combustion. In this study, the oil palm biomass fuels used were empty fruit bunches, oil palm fibers, oil palm midribs, and palm kernel shells. This research was carried out by a direct combustion method using a fluidized-bed combustor. The purpose of this experiment was to investigate the reaction of kinetics and the mechanism of combustion of oilpalm biomass in fluidized-bed combustor. The characteristics observed in this test were the combustion temperature profile, flue-gas composition, and the composition of the ash-deposit chemical compound. The results of the experiments conducted showed that the best biomass combustion temperature profile was recorded at 2 kg biomass with an air flow rate of 0.9375 m 3 /s at 90.1%. The maximum temperature of biomass combustion recorded at biomass 3 kg with an air flow rate of 1.25 m 3 /s are 950 o C (95%). The higher conversion combustion of biomass was found at biomass condition of 3 kg with an air flow rate of 0.9375 m 3 /s. The value of O2 emissions from biomass combustion shows that it was very small 0.2%. While the highest CO2 value was recorded at 19.9%. The highest combustion efficiency on FBC found 1 kg of biomass fuel with an air flow rate of 0.0654 m 3 /s recorded 94.9%.

The biomass gasification is one of the largest chemical transformation procedures of heat effectiveness. Numerical simulation is a significant instrument for studying biomass gasification. The numerical simulation of biomass gasification technologies at work and overseas is evaluated in this article. At the same moment, two commercial analysis applications (Aspen Plus and Fluent) applied in chemical processes were primarily implemented, both of which be there investigated and contrasted. In conclusion, it was suggested that is a better simulation outcome for biomass gasification could be obtained by implementing the Aspen Plus in combination with Fluent.

Better systems can be produced from various utility outputs that are integrated to make choices. The emergence of polygeneration after triggers and cogeneration can be used as sustainable solutions, making it possible to utilize resources optimally, efficiently and environmentally friendly. Polygeneration can be conceptualized with several possibilities because, theoretically, the working system has been well received as contained in some literature. Various scientific works have reported that the input and output vary greatly. The results of experimental analyses and prototypes developed have also been widely investigated and reported. Optimization tools that are based on the function of each objective are also used as a step to develop polygeneration effectively and efficiently. Polygeneration assessment has multidimensional criteria and their definitions can be applied based on cases with specific objectives. The main objective of this article is to comprehensively review the various literature available to investigate the status of polygeneration for renewable and sustainable energy solutions in the future. Various possible logical and predictable future works on polygeneration are also discussed at the end of this article.

Calcium oxide-based material is available abundantly and naturally. A potential resource of that material comes from marine mollusk shell such as clams, scallops, mussels, oysters, winkles and nerites. The CaO-based material has exhibited a good performance as the desulfurizer or adsorbent in coal combustion in order to reduce SO 2 emission. In this study, pulverized green mussel shell, without calcination, was utilized as the desulfurizer in the briquette produced from a mixture of low rank coal and palm kernel shell (PKS), also known as bio-briquette. The ratio of coal to PKS in the briquette was 90:10 (wt/wt). The influence of green mussel shell contents and combustion temperature were examined to prove the possible use of that material as a desulfurizer. The ratio of Ca to S