# Comparative Analysis of Agro Waste Material Solid Biomass Briquette for Environmental Sustainability

Authors: Sampathkumar Velusamy; Anandakumar Subbaiyan; Senthil Rajan Murugesan; Manoj Shanmugamoorthy; Vivek Sivakumar; Parthiban Velusamy; Senthilkumar Veerasamy; Kanitha Mani; Premkumar Sundararaj; Selvakumar Periyasamy
Journal: Advances in Materials Science and Engineering
 (2022)

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## Abstract

The agro waste briquettes produced from sorghum panicle and pearl millet with corn starch as the binder with varied proportions were compared with the other agro briquettes, and the elemental analysis of SP-PM briquettes was compared with the agro waste, palm kernel shell, soybean waste, mango leaves, rice husk, spruce, and coffee husk briquettes. The TGA results of SP-PM briquettes were compared with the corn leaf, baggase, almond shell, banana leaves, banana pseudostem, pineapple leaf, stem and root, low rank coal, bituminous coal, cotton stalk, and wheat straw. The DSC analysis that was carried out for SP-PM briquettes were compared with the rice husk char, spent coffee ground, wood chips, saw dust, wood straw, Tomsk peat, Sukhovskoy peat, Arkadievsky peat, nutshell, and bran. Thus, the briquettes made out of sorghum panicle and pearl millets are compared with the other biomass briquettes for its efficiency and its quality. Thus, the briquettes made out of sorghum panicle and pearl millets are compared with the other biomass briquettes for its efficiency and its quality.


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## Body

## 1. Introduction

Due to the industrialisation and increase in the population, there is a need for a larger amount of energy. At present, the energy demand is met by the fossil fuels [1]. Numerous researches show that there have been increasing alternatives for fossil fuels to meet the demand using renewable and natural energy resources such as solar energy, wind energy, geothermal, hydropower, and biomass since the crises of oil price [2].Since most of the developing countries across the world face the similar situation, conventional fuels such as coal, LPG, and kerosene are utilised only by a small percentage of people. Due to urbanisation and industrialisation, the conventional fuel is getting depleted gradually [3]. Fuel wood is a key source of energy in Indian villages. In semiurban areas, businesses such as restaurants, hotels, and brick kilns use fuel wood as one of the most important sources [4]. Eighty-three and half percentage rural home users account for the majority of fuel wood consumers, and twenty-three percentage urban household users account for the least [5]. India's 854 million people consume almost 216.4 MMTPA (million metric tonnes per annum). It is estimated that 27 percent of the aforementioned fuel use comes from publicly owned forests [6].According to the poll, 62.5 percent of families utilise wood as an energy source for cooking and other activities, but availability of fuel is the main barrier [7]. The rural population, in particular, is severely impacted by the increased demand. Furthermore, the use of firewood contributes to indoor air pollution and has a low burning efficiency [8, 9]. As in the instance of Delhi air pollution, the usage of conventional fuel creates significant air pollution. The traditional fuel is in high demand, and its price is steadily rising. Fossil fuel combustion generates main and secondary air pollutants such as nitrogen oxides and sulphur dioxide [10]. When these pollutants build up in the atmosphere, they generate acid rain, which has a negative impact on human health. As a result, there is an unwelcome need for an alternative fuel [11].There are various advantages over fossil fuels that could be used to fulfil future energy demands [12, 13]. Although it emits pollutants such as greenhouse gases, NOx, and SOx, it has a smaller environmental impact than fossil fuels [14]. The recent hike in the oil price has the tendency to increase continuously, approximately $65/barrel, and is expected to reach $75/barrel by the end of 2022. Not surprisingly then, the majority of the oil price forecasts remains at $65–70/barrel [15]. There will be a huge impact on Indian economy if the oil prices continue to rise in the upcoming years [16]. Hence, the biomass seems to be the best alternative for the fossil fuel which will eventually increase its popularity and draw attention from across the globe. Also, people who reside here outsource energy for cooking and other purposes. In order to bridge the gap between these two, biomass briquettes made of sorghum panicle and pearl millets are utilised; therefore, making it beneficiary for domestic and industrial purposes.


## 2. Various Sources of Materials

### 2.1. Biomass Feedstocks

Biomass feedstocks are sources of biomass for energy generation derived from municipal solid waste, sewage, algae, forest leftovers, wood processing, industries, agriculture, vegetable market trash, animal waste, fruit waste, and oil palm waste.


### 2.2. Sewage and Algae

Sewage comes under wet waste, and it means treated sludge from municipal waste water. Considerable revenue is generated for the people of rural areas by using the treated sludges for the production of biomass which also has an added advantage of solving the waste disposal problems. Algae are used as feedstocks for the production of bioenergy. The common types of algae include micro-, macro-, and cyanobacteria or blue green algae.


### 2.3. Agricultural Residues

Residues from the agricultural processes such as sorghum panicle, rice husk, straw from barley, wheat, and oats exist naturally and in abundance, and hence it can be considered as the best alternative for the availability of biomass. It creates additional revenue for the farmers and helps in the disposal of residues.


### 2.4. Industrial Residues

Residues from industries are also used as the biomass source which helps in the disposal problems of the left-over of the industries. The herbaceous crops such as bamboo, sweet sorghum, and wheat grass are found in common. These plants are not only useful for biomass production but also help in the improvement of ground water, soil quality, and the habitat of wildlife, and also, Figure1 shows the various sources of biomass.Figure 1
Various sources of biomass.


### 2.5. Materials Used

#### 2.5.1. Sorghum Panicle and Pearl Millet

The sorghum panicle and pearl millet been harvested in Tamil Nadu's Tiruppur district, Mulanur town (latitude 10.7655261; longitude 77.6940983). To obtain the desired molecular size of 2.36 mm, the biomass materials were left to dry, crushed, filtered, and pureed.The agricultural wastes produced in the Mulanur town is usually burnt due to immediate sowing of seasonal crops which caused severe pollution in and around the village. By the utilization of these wastes for the production of briquettes, we not only reduce the pollution but also reduce the energy demand for the village, thus making it self-reliant.


#### 2.5.2. Binders Used

The major benefits for using a 20% corn starch adhesive mixture in the manufacturing of briquettes are the superior physical features, increased compaction, low solubility, decreased incidence of degradation and growth of algae, and long handling and delivery.


## 2.1. Biomass Feedstocks

Biomass feedstocks are sources of biomass for energy generation derived from municipal solid waste, sewage, algae, forest leftovers, wood processing, industries, agriculture, vegetable market trash, animal waste, fruit waste, and oil palm waste.


## 2.2. Sewage and Algae

Sewage comes under wet waste, and it means treated sludge from municipal waste water. Considerable revenue is generated for the people of rural areas by using the treated sludges for the production of biomass which also has an added advantage of solving the waste disposal problems. Algae are used as feedstocks for the production of bioenergy. The common types of algae include micro-, macro-, and cyanobacteria or blue green algae.


## 2.3. Agricultural Residues

Residues from the agricultural processes such as sorghum panicle, rice husk, straw from barley, wheat, and oats exist naturally and in abundance, and hence it can be considered as the best alternative for the availability of biomass. It creates additional revenue for the farmers and helps in the disposal of residues.


## 2.4. Industrial Residues

Residues from industries are also used as the biomass source which helps in the disposal problems of the left-over of the industries. The herbaceous crops such as bamboo, sweet sorghum, and wheat grass are found in common. These plants are not only useful for biomass production but also help in the improvement of ground water, soil quality, and the habitat of wildlife, and also, Figure1 shows the various sources of biomass.Figure 1
Various sources of biomass.


## 2.5. Materials Used

### 2.5.1. Sorghum Panicle and Pearl Millet

The sorghum panicle and pearl millet been harvested in Tamil Nadu's Tiruppur district, Mulanur town (latitude 10.7655261; longitude 77.6940983). To obtain the desired molecular size of 2.36 mm, the biomass materials were left to dry, crushed, filtered, and pureed.The agricultural wastes produced in the Mulanur town is usually burnt due to immediate sowing of seasonal crops which caused severe pollution in and around the village. By the utilization of these wastes for the production of briquettes, we not only reduce the pollution but also reduce the energy demand for the village, thus making it self-reliant.


### 2.5.2. Binders Used

The major benefits for using a 20% corn starch adhesive mixture in the manufacturing of briquettes are the superior physical features, increased compaction, low solubility, decreased incidence of degradation and growth of algae, and long handling and delivery.


## 2.5.1. Sorghum Panicle and Pearl Millet

The sorghum panicle and pearl millet been harvested in Tamil Nadu's Tiruppur district, Mulanur town (latitude 10.7655261; longitude 77.6940983). To obtain the desired molecular size of 2.36 mm, the biomass materials were left to dry, crushed, filtered, and pureed.The agricultural wastes produced in the Mulanur town is usually burnt due to immediate sowing of seasonal crops which caused severe pollution in and around the village. By the utilization of these wastes for the production of briquettes, we not only reduce the pollution but also reduce the energy demand for the village, thus making it self-reliant.


## 2.5.2. Binders Used

The major benefits for using a 20% corn starch adhesive mixture in the manufacturing of briquettes are the superior physical features, increased compaction, low solubility, decreased incidence of degradation and growth of algae, and long handling and delivery.


## 3. Results and Discussion

### 3.1. Comparative Study on Elemental Analysis

Elemental Analysis: Table1 shows the comparative study on the elemental analysis of biomass briquettes. The produced biomass briquettes made of palm kernel shell and the results of elemental analysis had represented the percentage of carbon to be 46.28, percentage of hydrogen to be 5.59, percentage of oxygen to be 46.44, percentage of nitrogen to be 0.90, and percentage of sulphur to be 0.10. Biomass briquettes made of soybean waste and the results of elemental analysis had revealed the percentage of carbon to be 43.8, percentage of hydrogen to be 6.3, percentage of oxygen to be 48.5, percentage of nitrogen to be 1.4 and percentage of sulphur to be 0.8. Biomass briquettes made of mango leaves and the results of elemental analysis had displayed the percentage of carbon to be 45.20, percentage of hydrogen to be 5.49, percentage of oxygen to be 49.60, percentage of nitrogen to be 1.06, and percentage of sulphur to be nil. Biomass briquettes made of rice husk and the results of elemental analysis had showcased the percentage of carbon to be 45.20, percentage of hydrogen to be 5.80, percentage of oxygen to be 47.60, percentage of nitrogen to be 1.02 and percentage of sulphur to be 0.21 indicated in Figure 2.Table 1
Comparative study on elemental analysis of biomass briquettes.
Biomass briquettes% carbon% hydrogen% oxygen% nitrogen% sulphurReferencesPalm kernel shell46.285.5946.440.900.10[8]Soybean waste43.86.348.51.40.8[10]Mango leaves45.205.4949.601.060[11]Rice husk45.205.8047.601.020.21[12]Coffee husk47.56.443.700[14]Sugarcane leaves38.65.635.90.360.02[15]Wheat straw47.255.2846.680.610.18[16]Wood chips46.75.746.40.20.03[17]Almond leaves42.53.831.41.10.35[18]Saw dust53.074.139.60.280.302[19]Bagasse44.15.747.70.202.30[20]Sorghum panicle and pearl millets55.52041.9400.15This research 172Figure 2
Chemical composition of biomass briquettes.Furthermore, biomass briquettes made of spruce and the results of elemental analysis had recorded the percentage of carbon to be 46.68, percentage of hydrogen to be 6.85, percentage of oxygen to be 38.71, percentage of nitrogen to be 0.05 and percentage of sulphur to be 0.23. Biomass briquettes made of coffee husk and the results of elemental analysis showed the percentage of carbon to be 47.5, percentage of hydrogen to be 6.4, percentage of oxygen to be 43.7, percentage of nitrogen to be nil, and percentage of sulphur to be nil. Biomass briquettes made of sugarcane leaves and the results of elemental analysis had disclosed the percentage of carbon to be 38.6, percentage of hydrogen to be 5.6, percentage of oxygen to be 35.5, percentage of nitrogen to be 0.36, and percentage of sulphur to be 0.02. Recent research also revealed that the substitution of biomass briquettes for coal and wood could reduce PM2.5 emission by 63% approximately [17].


### 3.2. Comparative Study on Thermogravimetric Analysis

Table2 provides the comparative study on thermogravimetric analysis of biomass briquettes. Danish et al. [16] studied the combustion characteristics using the LECOTGA-701 analyzer on corn leaf briquettes under N2 atmosphere. It was indicated that the decomposition of the temperature was between 190°C and 560°C and the percentage of mass loss was at 25%. Setter et al. The authors of [21] determined the combustion characteristics using Shimadzu TGA/DTG-60H analyzer on coffee husk briquettes under N2 atmosphere. It was revealed from the study that the decomposition of temperature was between 190°C and 900°C, and the percentage of mass loss was at 34.68%. Wang et al. [22] explored the combustion characteristics using the Mettler Toledo TGA/SDTA Model 851 (Switzerland) analyzer on the wheat straw briquettes.Table 2
Comparative study on thermogravimetric analysis of biomass briquettes.
Biomass briquettesTg analyzerTg analyzer atmosphereDecomposition temperature (°C)Weight loss (%)ReferencesCorn leafLECOTGA-701N2190–56025[16]Coffee huskShimadzu TGA/DTG-60HN2190–90034.68[21]Wheat strawMettler Toledo TGA/SDTA Model 851 (Switzerland)NA390–77512[22]Banana leavesSTA Model 8000O232–9509[23]Cotton stalkTGAQ 500 (American TA Company)O2 + N2150–6008[24]MD2 pineapple leafPerkin Elmer STA-8000N20–90034.16[25]Low rank coalNETZSCH TG 209 F3N2400–90016[26]Empty fruit bunchMettler Toledo TGA/SDTA 851N250–90029.48[27]PseudostemNETZSCH STA-449F3O222–90032.14[4]Sorghum panicle and pearl milletsNETZSCH-STA-449F3N222–60027.93This researchIt was deeply explained that the decomposition of the temperature was between 390°C and 775°C and the percentage of mass loss was at 12%. Ku Ahmad et al. [23] researched the combustion characteristics using the STA Model 8000 analyzer on the banana leaves briquettes under O2 atmosphere. It was successfully found that the decomposition of temperature was between 32°C and 950°C and the percentage of mass loss was at 9%. Song et al. [24] examined the combustion characteristics using the TGA Q 500 (American TA company) analyzer on corn stalk briquettes under O2 and N2 atmosphere. From the study, it was clear that the decomposition of temperature was between 150°C and 600°C and the percentage of mass loss was 8%. Mansor et al. [25] worked on the combustion characteristics using the Perkin Elmer STA-8000 analyzer on pineapple leaves briquettes under N2 atmosphere. It was established that the decomposition of temperature was between 0°C and 900°C and the percentage of mass loss was 34.16%.Dwivedi et al. [26] studied the combustion characteristics using the NETZSCH STA-449F3 analyzer on low rank coal briquettes under N2 atmosphere. It was understood from the research that the decomposition of temperature was between 400°C and 900°C and the percentage of mass loss was 16%. Nyakuma et al. [27] assessed the combustion characteristics using the Mettler Toledo TGA/SDTA 851 analyzer on empty fruit bunch briquettes under N2 atmosphere. The study implied that the decomposition of temperature was between 50°C and 900°C and the percentage of mass loss was at 70%. Ismaila et al. [4] determined the combustion characteristics using the NETZSCH STA-449F3 analyzer on pseudostem briquettes under O2 atmosphere. It was well understood that the decomposition of temperature was between 22°C–900°C and the percentage of mass loss was 29.48%. Regarding this research work, the combustion characteristics using the NETZSCH-STA-449F3 analyzer on empty fruit bunch briquettes under N2 atmosphere were examined.It was revealed that the decomposition of temperature was between 22°C and 600°C and the percentage of mass loss was attained at 27.93%. From the procured results and the analysis of the samples which had gone through the process of decomposition in comparing with the other biomass briquettes, the briquettes made of sorghum panicle and pearl millets (80 : 20) would be ideal feedstock samples during combustion and could be effectively used for the industrial applications.


### 3.3. Comparative Study on Differential Scanning Calorimetric Analysis

Table3 provides the comparative study on differential scanning calorimetric analysis of biomass briquettes. According to Maiti et al. [28], the biomass briquettes made of rice husk char showed the exothermic reaction. Also, the exothermic peak was recorded at the temperature of 446.67°C approximately and thus revealed that the rice husk char released heat during the heating process. The spent coffee ground briquettes produced by Espuelas et al. [29] exhibited the exothermic reaction. The highest peak of exothermic reaction was attained for the xanthum gum combination of the spent coffee ground at the temperature of 515°C, and the raw spent coffee ground had its highest peak value around 550°C. A combination of exothermic and endothermic reaction was obtained for the briquettes made of wood chips, saw dust, and wood straw produced by Tabakaev et al. [30]. The endothermic peaks were acquired between the temperatures of 20°C and 120°C and also indicated that the moisture from the sample got evaporated. Only one exothermic curve was attained between the temperatures of 220°C and 575°C for the briquette samples. Tomsk peat, Sukhovskoy peat, and Arkadievsky peat briquettes produced by De Oliveira Maia et al. [31] had revealed the combination reaction of exothermic and endothermic with two exothermic peaks which were obtained between the temperatures of 200°Cand 340°C and 370°C and 570°C, respectively, from the peat samples indicating transfer of heat from the system to the surrounding.Table 3
Comparative study on differential scanning calorimetric analysis of biomass briquettes.
Biomass briquettesReactionInferenceReferencesRice husk charExothermicThe peak was recorded by the sample at a temperature of about 446.67°C, showing that heat is released by rice husk char during the heating process[28]Spent coffee ground (SPG)ExothermicXanthum gum combination of the SPG recorded highest peak at 515°C, whereas raw SPG had its highest peak value around 550°C[29]Wood chips, saw dust, and wood strawA combination of exothermic and endothermicBetween 20°C–120°C, the samples showed endothermic peaks, indicating evaporation of moisture from the sample. The samples recorded only one exothermic curve between 220°C–575°C.[30]Tomsk peat, Sukhovskoy peat, and Arkadievsky peatA combination of exothermic and endothermicTwo exothermic peaks, between 200°C and 340°C and 370°C and 570°C, respectively, were shown by the peat samples indicating transfer of heat from the system to the surrounding[31]Nutshell and branA combination of exothermic and endothermicTwo exothermic peaks, between 225°C and 460°C and 480°C and 600°C, respectively, were shown by nutshell and bran indicating heat loss to the surrounding[30]Sorghum panicle and pearl milletsA combination of exothermic and endothermicTwo exothermic peaks, between 225°C and 340°C and 340°C and 370°C, respectively, were shown by sorghum panicle and pearl millets indicating the release of energy due to the decomposition of fixed carbon and residual ligninThis researchTabakaev et al. [30] produced the biomass briquettes using nutshell and bran where the combinations of exothermic and endothermic reactions were observed for the briquette samples. Two exothermic peaks were obtained between the temperatures 225°C and 460°C and 480°C and 600°C indicating loss of heat in the surrounding. This research which includes sorghum panicle and pearl millets in the combination of 80 : 20 showed both (exothermic and endothermic) reactions. Two exothermic peaks were attained between 225°C and 340°C and 340°C and 370°C indicating the release of energy due to the decomposition of fixed carbon and residual lignin. By comparing SP-PM briquettes with the other biomass briquettes, the briquettes made of sorghum panicle with 80% and pearl millets with 20% proved to obtain good combustion characteristics.


## 3.1. Comparative Study on Elemental Analysis

Elemental Analysis: Table1 shows the comparative study on the elemental analysis of biomass briquettes. The produced biomass briquettes made of palm kernel shell and the results of elemental analysis had represented the percentage of carbon to be 46.28, percentage of hydrogen to be 5.59, percentage of oxygen to be 46.44, percentage of nitrogen to be 0.90, and percentage of sulphur to be 0.10. Biomass briquettes made of soybean waste and the results of elemental analysis had revealed the percentage of carbon to be 43.8, percentage of hydrogen to be 6.3, percentage of oxygen to be 48.5, percentage of nitrogen to be 1.4 and percentage of sulphur to be 0.8. Biomass briquettes made of mango leaves and the results of elemental analysis had displayed the percentage of carbon to be 45.20, percentage of hydrogen to be 5.49, percentage of oxygen to be 49.60, percentage of nitrogen to be 1.06, and percentage of sulphur to be nil. Biomass briquettes made of rice husk and the results of elemental analysis had showcased the percentage of carbon to be 45.20, percentage of hydrogen to be 5.80, percentage of oxygen to be 47.60, percentage of nitrogen to be 1.02 and percentage of sulphur to be 0.21 indicated in Figure 2.Table 1
Comparative study on elemental analysis of biomass briquettes.
Biomass briquettes% carbon% hydrogen% oxygen% nitrogen% sulphurReferencesPalm kernel shell46.285.5946.440.900.10[8]Soybean waste43.86.348.51.40.8[10]Mango leaves45.205.4949.601.060[11]Rice husk45.205.8047.601.020.21[12]Coffee husk47.56.443.700[14]Sugarcane leaves38.65.635.90.360.02[15]Wheat straw47.255.2846.680.610.18[16]Wood chips46.75.746.40.20.03[17]Almond leaves42.53.831.41.10.35[18]Saw dust53.074.139.60.280.302[19]Bagasse44.15.747.70.202.30[20]Sorghum panicle and pearl millets55.52041.9400.15This research 172Figure 2
Chemical composition of biomass briquettes.Furthermore, biomass briquettes made of spruce and the results of elemental analysis had recorded the percentage of carbon to be 46.68, percentage of hydrogen to be 6.85, percentage of oxygen to be 38.71, percentage of nitrogen to be 0.05 and percentage of sulphur to be 0.23. Biomass briquettes made of coffee husk and the results of elemental analysis showed the percentage of carbon to be 47.5, percentage of hydrogen to be 6.4, percentage of oxygen to be 43.7, percentage of nitrogen to be nil, and percentage of sulphur to be nil. Biomass briquettes made of sugarcane leaves and the results of elemental analysis had disclosed the percentage of carbon to be 38.6, percentage of hydrogen to be 5.6, percentage of oxygen to be 35.5, percentage of nitrogen to be 0.36, and percentage of sulphur to be 0.02. Recent research also revealed that the substitution of biomass briquettes for coal and wood could reduce PM2.5 emission by 63% approximately [17].


## 3.2. Comparative Study on Thermogravimetric Analysis

Table2 provides the comparative study on thermogravimetric analysis of biomass briquettes. Danish et al. [16] studied the combustion characteristics using the LECOTGA-701 analyzer on corn leaf briquettes under N2 atmosphere. It was indicated that the decomposition of the temperature was between 190°C and 560°C and the percentage of mass loss was at 25%. Setter et al. The authors of [21] determined the combustion characteristics using Shimadzu TGA/DTG-60H analyzer on coffee husk briquettes under N2 atmosphere. It was revealed from the study that the decomposition of temperature was between 190°C and 900°C, and the percentage of mass loss was at 34.68%. Wang et al. [22] explored the combustion characteristics using the Mettler Toledo TGA/SDTA Model 851 (Switzerland) analyzer on the wheat straw briquettes.Table 2
Comparative study on thermogravimetric analysis of biomass briquettes.
Biomass briquettesTg analyzerTg analyzer atmosphereDecomposition temperature (°C)Weight loss (%)ReferencesCorn leafLECOTGA-701N2190–56025[16]Coffee huskShimadzu TGA/DTG-60HN2190–90034.68[21]Wheat strawMettler Toledo TGA/SDTA Model 851 (Switzerland)NA390–77512[22]Banana leavesSTA Model 8000O232–9509[23]Cotton stalkTGAQ 500 (American TA Company)O2 + N2150–6008[24]MD2 pineapple leafPerkin Elmer STA-8000N20–90034.16[25]Low rank coalNETZSCH TG 209 F3N2400–90016[26]Empty fruit bunchMettler Toledo TGA/SDTA 851N250–90029.48[27]PseudostemNETZSCH STA-449F3O222–90032.14[4]Sorghum panicle and pearl milletsNETZSCH-STA-449F3N222–60027.93This researchIt was deeply explained that the decomposition of the temperature was between 390°C and 775°C and the percentage of mass loss was at 12%. Ku Ahmad et al. [23] researched the combustion characteristics using the STA Model 8000 analyzer on the banana leaves briquettes under O2 atmosphere. It was successfully found that the decomposition of temperature was between 32°C and 950°C and the percentage of mass loss was at 9%. Song et al. [24] examined the combustion characteristics using the TGA Q 500 (American TA company) analyzer on corn stalk briquettes under O2 and N2 atmosphere. From the study, it was clear that the decomposition of temperature was between 150°C and 600°C and the percentage of mass loss was 8%. Mansor et al. [25] worked on the combustion characteristics using the Perkin Elmer STA-8000 analyzer on pineapple leaves briquettes under N2 atmosphere. It was established that the decomposition of temperature was between 0°C and 900°C and the percentage of mass loss was 34.16%.Dwivedi et al. [26] studied the combustion characteristics using the NETZSCH STA-449F3 analyzer on low rank coal briquettes under N2 atmosphere. It was understood from the research that the decomposition of temperature was between 400°C and 900°C and the percentage of mass loss was 16%. Nyakuma et al. [27] assessed the combustion characteristics using the Mettler Toledo TGA/SDTA 851 analyzer on empty fruit bunch briquettes under N2 atmosphere. The study implied that the decomposition of temperature was between 50°C and 900°C and the percentage of mass loss was at 70%. Ismaila et al. [4] determined the combustion characteristics using the NETZSCH STA-449F3 analyzer on pseudostem briquettes under O2 atmosphere. It was well understood that the decomposition of temperature was between 22°C–900°C and the percentage of mass loss was 29.48%. Regarding this research work, the combustion characteristics using the NETZSCH-STA-449F3 analyzer on empty fruit bunch briquettes under N2 atmosphere were examined.It was revealed that the decomposition of temperature was between 22°C and 600°C and the percentage of mass loss was attained at 27.93%. From the procured results and the analysis of the samples which had gone through the process of decomposition in comparing with the other biomass briquettes, the briquettes made of sorghum panicle and pearl millets (80 : 20) would be ideal feedstock samples during combustion and could be effectively used for the industrial applications.


## 3.3. Comparative Study on Differential Scanning Calorimetric Analysis

Table3 provides the comparative study on differential scanning calorimetric analysis of biomass briquettes. According to Maiti et al. [28], the biomass briquettes made of rice husk char showed the exothermic reaction. Also, the exothermic peak was recorded at the temperature of 446.67°C approximately and thus revealed that the rice husk char released heat during the heating process. The spent coffee ground briquettes produced by Espuelas et al. [29] exhibited the exothermic reaction. The highest peak of exothermic reaction was attained for the xanthum gum combination of the spent coffee ground at the temperature of 515°C, and the raw spent coffee ground had its highest peak value around 550°C. A combination of exothermic and endothermic reaction was obtained for the briquettes made of wood chips, saw dust, and wood straw produced by Tabakaev et al. [30]. The endothermic peaks were acquired between the temperatures of 20°C and 120°C and also indicated that the moisture from the sample got evaporated. Only one exothermic curve was attained between the temperatures of 220°C and 575°C for the briquette samples. Tomsk peat, Sukhovskoy peat, and Arkadievsky peat briquettes produced by De Oliveira Maia et al. [31] had revealed the combination reaction of exothermic and endothermic with two exothermic peaks which were obtained between the temperatures of 200°Cand 340°C and 370°C and 570°C, respectively, from the peat samples indicating transfer of heat from the system to the surrounding.Table 3
Comparative study on differential scanning calorimetric analysis of biomass briquettes.
Biomass briquettesReactionInferenceReferencesRice husk charExothermicThe peak was recorded by the sample at a temperature of about 446.67°C, showing that heat is released by rice husk char during the heating process[28]Spent coffee ground (SPG)ExothermicXanthum gum combination of the SPG recorded highest peak at 515°C, whereas raw SPG had its highest peak value around 550°C[29]Wood chips, saw dust, and wood strawA combination of exothermic and endothermicBetween 20°C–120°C, the samples showed endothermic peaks, indicating evaporation of moisture from the sample. The samples recorded only one exothermic curve between 220°C–575°C.[30]Tomsk peat, Sukhovskoy peat, and Arkadievsky peatA combination of exothermic and endothermicTwo exothermic peaks, between 200°C and 340°C and 370°C and 570°C, respectively, were shown by the peat samples indicating transfer of heat from the system to the surrounding[31]Nutshell and branA combination of exothermic and endothermicTwo exothermic peaks, between 225°C and 460°C and 480°C and 600°C, respectively, were shown by nutshell and bran indicating heat loss to the surrounding[30]Sorghum panicle and pearl milletsA combination of exothermic and endothermicTwo exothermic peaks, between 225°C and 340°C and 340°C and 370°C, respectively, were shown by sorghum panicle and pearl millets indicating the release of energy due to the decomposition of fixed carbon and residual ligninThis researchTabakaev et al. [30] produced the biomass briquettes using nutshell and bran where the combinations of exothermic and endothermic reactions were observed for the briquette samples. Two exothermic peaks were obtained between the temperatures 225°C and 460°C and 480°C and 600°C indicating loss of heat in the surrounding. This research which includes sorghum panicle and pearl millets in the combination of 80 : 20 showed both (exothermic and endothermic) reactions. Two exothermic peaks were attained between 225°C and 340°C and 340°C and 370°C indicating the release of energy due to the decomposition of fixed carbon and residual lignin. By comparing SP-PM briquettes with the other biomass briquettes, the briquettes made of sorghum panicle with 80% and pearl millets with 20% proved to obtain good combustion characteristics.


## 4. Recommendations and Future Scope

(i)
It is recommended to use statistical tools such as ANOVA and Tukey’s test for the analysis of data which can give effective correlation between two or more data(ii)
It is also recommended to adopt different principles for briquetting machine driving so as to draw a clearer comparison between the results obtained for the various types of technologies(iii)
The authors also suggest to carry out the ash analysis of the produced sorghum panicle and pearl millet briquettes(iv)
The authors finally suggest to use optimization tools to deal with multiple variables found out experimentally in order to carry out optimization studies


## 5. Conclusion

The acquired results for elemental, thermogravimetric, and differential scanning calorimetric analysis that were conducted for SP-PM briquettes were discussed extensively in this paper. Furthermore, the SP-PM briquette with the ratio of 80 : 20 was compared with the other biomass briquettes that were used in several studies in terms of elemental, TGA and DSC analysis. By comparing SP-PM briquettes with the other various biomass samples (banana leaves, sugarcane baggase, groundnut shell, saw dust, neem, rice husk, soda weed, mango leaves, maize straw, almond leaves, coffee husk, palm kernel shell, cotton stalks, pine wood, pineapple leaf etc.), it was confirmed that the material chosen had provided an optimum result than the other biomass materials. By comparing SP-PM briquettes with the other biomass briquettes, the briquettes made of sorghum panicle with 80% and pearl millets with 20% proved to obtain good combustion characteristics and in order to reduce the energy demand in the industries and residences in the village.



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*Source: 3906256-2022-05-19.xml*