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Power generation utilizing biomass thermal conversion has become one of the clean energy solutions. Arthrospira platensis (AP) microalgae belongs to 3rd-gen biomass. AP has high protein and relatively low ash content compared to other microalgae. On the other hand, AC has a high energy density and also provides a catalytic effect due to its high surface area. Inorganic material is one of the main factors in determining the potential of thermal conversion feedstock. Reactor fouling is caused by inorganic deposits, resulting in a decrease in heat transfer efficiency. Inorganic elements (Na, K, Ca, and Mg) also interact with biomasses' volatile matter, reducing thermal conversion to final product quality, such as pyrolysis oil. This study aimed to analyze inorganic elements change and its possible interaction with the thermal conversion product of AP and AC mixture at a mass ratio of 10:1 (10AP:1AC) compared to parent material using X-ray fluorescence (XRF) spectroscopy. The result indicated that AP contained chlorine and potassium as major inorganic elements of 54.8 and 19.6 (wt.%), respectively. AC inorganic elements are dominated by calcium and iron at 33.6 and 19.8 (wt.%) in that order. Blending AP and AC does not drastically increase total inorganic elements with maximum change in iron with 0.92%, which is the desired output where there is feedstock quality improvement without significant inorganic element increase. [ABSTRACT FROM AUTHOR]

Global energy security is extremely uncertain, considering the world energy supply still depends on fossil energy from certain countries. Fossil energy is not renewable and is not environmentally friendly. Compared to fossil energy, biomass can be renewed and reduce CO2 emissions because there is a balance between CO2 absorption during biomass growth and CO2 emissions generated during the combustion process. One biomass that can be converted into fuel is the microalgae Spirulina sp. This species can be cultivated faster and does not require a large area compared to other biomasses. In this study, Spirulina sp and its simulated model compound composed of glycine, starch, and castor oil as a model of a protein, carbohydrate, and lipid were thermally characterized to understand the detail of its biomass thermal decomposition. The proportion of a simulated model compound was equal to the dry basis content of protein, lipid, and carbohydrate in Spirulina sp. Overall, samples were tested under a thermogravimetry analyzer to determine their thermal characteristics. The results show that the Spirulina sp had a more complex thermal decomposition than the simulated model compound. [ABSTRACT FROM AUTHOR]

High dependence on fossil energy sources is still a major problem in the national energy supply. To overcome these problems, the government encourages the utilization of renewable energy sources, one of which is biomass energy. Arthrospira platensis is one of the potential biomass as a future renewable energy source. This study aims to understand the thermal behavior and determine the kinetic parameter of the Arthrospira platensis activated carbon mixture with mass ratios of 10:3 during the combustion process. Thermal behavior analysis was carried out with the thermogravimetric analysis (TGA) instrument under the heating rates of 10 ℃/min using an oxygen flow rate of 100 ml/min with a temperature range of 25−1000 ℃. The results of the TGA showed that the mixed samples underwent three decomposition processes: moisture removal, volatile matter release, and solid residue decomposition. The Coats-Redfern fitting method was applied to calculate the activation energy in 2nd stage of decomposition by using ten reaction models. The result indicated that the order reaction model of F1 and the diffusion model of D1 were the most proper models for Phase I and II, respectively. [ABSTRACT FROM AUTHOR]

The biomass briquet in this research was intended to provide a fuel alternative with better combustion characteristics to reduce household air pollution (HAP) in remote communities. This article presented the effect of mixture ratio and densification pressure on the water resistance characteristics of a bio-briquette composed of carbonized rice husk (CRH) bound by Eichhornia crassipes (EC). The CRH and EC mass ratios are 80/20 (CRH80/EC20) and 20/80 (CRH20/EC80). The bio-briquettes were fabricated using a hydraulic press machine at 25 and 50 MPa pressure. The water resistance analysis was performed according to the ASTM D779-03 standard. The result shows that the highest water resistance was observed at 80CRH/20EC at a densification pressure of 50 MPa. [ABSTRACT FROM AUTHOR]

Coconut, as an evergreen plant, grows abundantly and generates coconut shell waste (CSW) as a by-product, often mistreated when it can be used as a renewable energy source. This research aims to study the kinetics of CSW combustion through thermogravimetric analysis (TGA). The sample was combusted from a temperature of around 27℃ to 1000 ° C at a constant heating rate of 30 ° C min-1 and an airflow rate of 100 ml min−1. The thermogravimetric (TG) and derivative thermogravimetric (DTG) curves show that the thermal decomposition of the CSW existed in three phases: from room temperature to 135 ° C occurred the release of moisture content, followed by a phase of active combustion in which cellulose and hemicellulose were decomposed and burned, and finally after the temperature of 550℃ was the solid residue decomposition occurred. The combustion kinetic parameters of CSW were evaluated using Horowitz-Metzger's integral method. The moisture content release phase possessed a lower activation energy value (80.99 kJ mol−1) compared to the main phase of the biomass combustion of CSW (127.80 kJ mol−1). Thermodynamic parameters were investigated as well, and it was revealed that a certain amount of heat was needed to decompose the CSW sample into an activated complex throughout the combustion reaction. [ABSTRACT FROM AUTHOR]

The chemical contents of aquatic biomass, such as microalgae, have an essential role in determining its potential as a fuel feedstock. The known major components of microalgae are carbohydrate, protein, and lipid, each of which also has different roles during the thermal conversion process. Therefore, examining the compositions of microalgae and its model components of carbohydrate, protein, and lipid is critical to better understanding the role of each component for fuel purposes. This paper presented the chemical contents of microalgae Spirulina sp and its two model components of carbohydrate and protein. These starch and glycine were considered as the model of pure carbohydrate and protein. The chemical compositions of the samples were examined using Energy-Dispersive X-ray Spectroscopy. The results show that the major components present in the Spirulina sp were carbon (C) at around 63% and oxygen (O) at around 28%, and the rest were mineral matters, such as Na, Mg, P, S, and Cl. The starch as carbohydrate model contained the C by 60% and O by 39%, whereas Mg was the only minor mineral element present. The protein component modeled by glycine comprises C by 39%, N by 19%, and O by 42%. Each element significantly determined the thermal behavior during the conversion process and affected the products produced. The chemical contents of lipid have yet to be examined in this recent paper and will be studied in future work. [ABSTRACT FROM AUTHOR]

The basic properties of microalgae Spirulina sp have been characterized and compared with its two model components of carbohydrate and protein. The Spirulina sp samples were cultivated by the Brackishwater Aquaculture Development Center, Situbondo, Indonesia. The two pure carbohydrate and protein models were each represented by starch and glycine, each obtained from Sigma Aldrich (Singapore) and HiMedia India, respectively. The ultimate and proximate tests were performed to explore their chemical and physical properties. The adiabatic bomb calorimeter was employed to understand their heating value. It was observed that carbon is the component that makes up the majority of Spirulina sp, the value of which is 45.56 (wt%,db), whereas in the two model components of starch and glycine, the most dominant ingredients were oxygen, which are that of 49.37 and 40.51 (wt%,db), respectively. The proximate analyses showed that volatile matter presented as the largest constituent for the overall sample; 76.76, 94.29 and 88.62 (wt%,db), each for Spirulina sp, starch, and glycine. From these ultimate and proximate datasets, it is clear that most of the carbon content in Spirulina sp formed the volatilized matter during the thermal processes, whereas a small portion would be fixed carbon. The gross calorific values of Spirulina sp, starch, and glycine were tested according to the ASTM D 5865-19 standard, resulting in the respective values of 4971, 0, and 3870 kcal/kg. These results confirmed that the starch had less significance in determining the heating value, and protein was probably more prominent in this role. To complete this analysis, the role of lipid as the remaining primary component in microalgae that is yet to be presented in this paper would have to be explored in-depth in future work. [ABSTRACT FROM AUTHOR]

Particle size and porosity are critical physical properties of biomass that would affect its thermal conversion. The diffusion of substances, mass transfer process, and trapping during thermal treatment of biomass are highly dependent on both properties. Therefore, understanding these physical properties is essential in conducting a biomass thermochemical process to harness energy from renewable sources, such as microalgae. This paper presents the particle size distribution (PSD) and porosity of the microalgae Arthrospira platensis (AP) added activated carbon (AC) by a mass ratio of 100AP/30AC. The homogeneous blend was achieved by stirring together the materials at 1200 rpm for 30 min. The images of the sample were then taken using a scanning electron microscope (SEM). From the image produced, the particle size and porosity were analyzed. The result indicated that most of the particles observed in the blended sample were of the size 30 and 50 µm. It is strongly hypothesized that particles sized between 0-30 µm would affect the products of the tar, gas, and bio-oil during the pyrolysis process, while particles between 30-50 µm would significantly influence the yield of char products. It was also found that the blended materials have a porosity of around 59.35%. These pores would facilitate oxygen diffusion during the thermal oxidizing process, leading to greater combustion reactivities. In pyrolysis, these pores would facilitate various processes, such as heat and mass transfer to the inner surface, and affecting the products produced from this process. Nevertheless, a future in-depth study is needed to understand how AC significantly affects pore formation in the AP by comparing the blended sample to the parent of both materials. [ABSTRACT FROM AUTHOR]

FTIR analysis has provided corroboration to the basic analysis of biomass for understanding their potential as a fuel feedstock. This apparatus afforded a dataset related to the organic component that would probably be volatilized, liquidized, and solidified during thermal processes. It also detailed the inorganic substances contained in the materials that potentially produced a solid residue as a by-product in the final thermal processes. This work presented the identification of macromolecular contents in the blended materials between microalgae Arthrospira platensis (AP) and activated carbon (AC) by using FTIR spectroscopy. The blended sample was provided by the route of the mixing process of both samples in a mass ratio of 100AP/50AC. Both sample mixtures were stirred together using mechanical stirring at 1200 rpm for 30 min to ensure the homogeneity of the final sample produced. The potassium bromide powder was mixed with the blended sample then subjected to the pressure to form the pellets with a transparent sheet that was appropriately used to measure the infrared spectrum. A wide range of FTIR spectrum between 4000 and 400 cm−1 is recorded in such an event. The resulted band spectra revealed the existence of three principles macromolecular contained in the microalgal sample, i.e., protein, carbohydrate, and lipid. However, for an in-depth understanding of how AC affected the structure of the functional group in the algal biomass, future work is needed for comparing this result with each parent of AP and AC. [ABSTRACT FROM AUTHOR]