4.3. Proximate and ultimate analyses of CCCh and GNSCh at different pyrolysis temperature

Proximate and Ultimate analysis of CCCh and GNSCh are shown in Table 3. volatile matter (VM) content of biochar decreases with increase in pyrolysis temperature i.e., 32.48–5.56% and 30.80–6.48% in case of CCCh and GNSCh respectively. The presence of lignin in the agricultural biomass waste material can partially resist pyrolytic decomposition at lower temperature but not in case at temperatures as high as 950C [26]. The CCCh and GNSCh showed a high ash content, and this may be because of the partial change in the composition promoted by a possible relation between organic and inorganic constituents [26]. It can be seen that biochars with higher content of ash generally have the lower values of fixed carbon and vice versa. Similarly fixed carbon (FC) in CCCh and GNSCh varies from 45.25–84.32% and 49.91–85.06%, respectively.

Further the ultimate analysis of CCCh and GNSCh varies significantly in respect of C, H, N, S, and O contents, which is tabulated in Table 3.

FT-IR Analysis of the CC, GNS, and their derived char at different pyrolysis temperature.

4.2. Yield, pH, and GCV of the biochars

M %

> ( C)

Biochar samples Temperature

210 Energy Systems and Environment

VM %

Table 1. Proximate and Ultimate analysis (as received basis) of CC and GNS.

Table 2. Physiochemical characteristics of CCCh and GNSCh at different temperatures.

Ash %

the atmosphere and sequestered.

Physiochemical characteristics like, Yield%, pH, and GCV of the derived biochars at different temperatures from CC and GNS are shown in Table 2. From this table it is observed that there is relatively higher percentage of yield at 350C of pyrolysis, which further decreases with increase in temperature up to 950C. From this table, it is observed that there is relatively higher yield of chars at lower temperature of pyrolysis, which further decreases progressively with increase in temperature. Reduction in the bio-char yield at high temperatures is attributable to undergoing the secondary reactions of the bio-char formed during the primary pyrolysis, which lead to the formation of liquid and gaseous products at the cost of solid char [18]. The energy given to the biomass at high temperature may exceed the bond breaking energy which supports the release of the volatile components of the biomass in the form of gases resulting in less char yield [19]. The reduction in the bio-char yield with increase in pyrolysis temperature is also reported by other workers [20, 21]. As with the biomass feedstocks, the char products have energy values roughly related to their carbon contents. Release of this energy by combustion can again be considered as renewable and is largely carbon neutral; the carbon returned to the atmosphere as carbon dioxide is the same as would otherwise have resulted from biomass decomposition. If the char product is not burnt, but retained in a way that the carbon in it is stable, then that carbon can be equated to carbon dioxide removed from

ABW samples Proximate analysis Ultimate analysis GCV(MJ/kg)

C % N %

550 28.34 9.49 19.73 750 25.65 10.11 22.26 950 22.04 11.08 23.12

550 41.39 8.83 20.51 750 38.53 9.50 22.46 950 35.35 10.41 23.50

H %

Biochar energy yield (%) pH GCV

S % O %

(MJ/Kg)

FC %

Coconut coir (CC 3.36 80.73 0.94 14.97 47.78 0.19 5.87 0.11 46.14 14.74 Ground nut shell (GNS) 4.54 79.54 1.79 14.13 45.50 0.46 5.44 0.15 48.45 14.03

CCCh 350 30.60 8.04 16.40

GNSCh 350 48.50 7.70 17.58

Figure 1 (a) and (b) shows the FTIR spectra of CC, GNS, and their derived char at different pyrolysis temperatures. These graphs are plotted against wave numbers and transmittance


Table 3. Proximate\* and ultimate analysis of CCCh and GNSCh at different pyrolysis temperature.

Figure 1. FTIR analysis of (a) coconut coir (CC) and (b) ground nut shell (GNS) and their derived char at different temperatures.

percentage, which show the aliphatic loss in their functional group. The AWB samples (CC and GNS) have bands at 3401-3420 cm<sup>1</sup> (O-H stretching), 2940-2955 cm<sup>1</sup> (CH, CH2 stretching), 1600-1645 cm<sup>1</sup> (C=C stretching), 1510-1520 cm<sup>1</sup> (benzene ring), 1420-1470 cm<sup>1</sup> (aromatic skeletal vibrations; asymmetric in -CH3 and -CH2-), 1310-1380 cm<sup>1</sup> (Phenolic OH; aliphatic C-H deformation vibrations in cellulose and hemicelluloses), 1210-1245 cm<sup>1</sup> (C-O-C stretching in alkyl aromatic), (1140-1161 cm<sup>1</sup> (C-O-C asymmetry stretching), 1030-1060 cm<sup>1</sup> (C-O stretching).

From the FTIR spectra of CHCh and SBCh, it is seen from Figure 1 (a) and (b), that the aliphatic losses are represented by the C-H stretching (2800-2950 cm<sup>1</sup> ) with increasing in pyrolysis temperature [27]. The representative peaks seemed for aromatic carbon C-H stretching (3050- 3000 cm<sup>1</sup> ), C=C (1350-1450 cm<sup>1</sup> ), C-C, and C-O stretching (1580-1730 cm<sup>1</sup> ) [28–30]. This is obviously because the pyrolysis temperature amends the functional group. It can be seen from result aliphatic C group decreases but aromatic C group increases [31]. But, when the pyrolysis temperature becomes high, the intensity of the bands such as that of the hydroxyl groups (3210-3450 cm<sup>1</sup> ) and aromatic groups (1550-1650 and 3050-3250 cm<sup>1</sup> ) [27, 32], gradually diminishes.

range implies that there was incomplete combustion with low efficiency and high pollutant

Biochar Derived from Agricultural Waste Biomass Act as a Clean and Alternative Energy Source of Fossil Fuel…

http://dx.doi.org/10.5772/intechopen.73833

213

Figure 2. TG and DTG curve of coconut coir (CC) its derived char at different temperatures.

Compared to raw biomass, the reactivity of the biochar decreased, resulting in a higher ignition temperature and combustion in a wider temperature range. The elevated combustion temperature with high weight loss rate implies improved combustion safety, increased combustion efficiency and decreased pollutant emission. These combustion characteristics of biochar are significant improvements over raw biomass feedstock as a fuel [33, 34]. Generally, two separate peaks can be seen for all derived biochars in an inert atmosphere [35], where the first one is assigned to the thermal decomposition of hemicelluloses and the second one is for the cellulose and lignin decomposition, which covers a longer range. From the DTG profile, the initial mass loss at about 70C is due to the moisture present in the sample. In the second stage from 295 to 308C with maximum weight loss rate obtained at 310C is attributable to the hemicelluloses degradation. The third stage appeared from 355 to 405C with maximum decomposition rate at 355C. Compared with these three components, lignin was the most

From the DTG curve of CCCh(350C) and GNSCh(350C), it can be seen that the degradation of cellulose and hemi-cellulose is complete. But the DTG profile of the CCCh(550–<sup>750</sup>C) and GNSCh (550–<sup>750</sup>C) indicates that the decomposition of lignin is complete, and attains steady state at

difficult one to decompose even at higher temperature.

CCCh(950C) and GNSCh(950C).

emissions [33].
