Isothermal Drying Kinetic Study of Spent Coffee Grounds Using Thermogravimetric Analysis

Table 3

Values of the coefficient in the modified Henderson–Pabis model and its performance.

Nr.	Layer thicknesses, (mm)	Temperature, (°C)	Model	Model parameters	r^2	σ
1.	0.6 mm	50	Modified Henderson–Pabis	a = 1.1674	0.9931	0.0287
				b = 1.826010^−6
				c = −0.0775
				k = 0.0016
		60	Modified Henderson–Pabis	a = 1.1099	0.9917	0.0255
				b = 4.896210^−6
				c = −0.0161
				k = 0.0030
		70	Modified Henderson–Pabis	a = 1.0798	0.9928	0.0208
				b = 9.987910^−7
				c = −0.0002
				k = 0.0043
		80	Modified Henderson–Pabis	a = 1.0474	0.9954	0.0152
				b = −2.059610^−6; c = 0.0126
				k = 0.0053
2	1.2 mm	50	Logarithmic	a = 1.2073	0.9925	0.0393
				c =−0.1297
				k = 0.0008
		60	Modified Henderson–Pabis	a = 1.4671	0.9948	0.0293
				b = 0.0001
				c = −0.3951
				k = 0.0011
		70	Modified Henderson–Pabis	a = 1.2249	0.9934	0.0300
				b = 4.533210^−5
				c = −0.1379
				k = 0.0018
		80	Modified Henderson–Pabis	a = 1.1213	0.9931	0.0253
				b = 1.187310^−5
				c = −0.0303
				k = 0.0035
3.	1.8 mm	50	Logarithmic	a = 1.4724	0.9971	0.0243
				c = −0.4370
				k = 0.0004
		60	Modified Henderson–Pabis	a = 12.7591	0.9975	0.0222
				b = 0.0013
				c = −11.7242
				k = 0.0002
		70	Modified Henderson–Pabis	a = 1.3328	0.9942	0.0301
				b = 7.748210^−5
				c = −0.2558
				k = 0.0013
		80	Modified Henderson–Pabis	a = 1.1483	0.9942	0.0262
				b = 2.276410^−6
				c = −0.0638
				k = 0.0024
4.	2.4 mm	50	Logarithmic	a = 1.2662	0.9950	0.0319
				c = −0.2151
				k = 0.0004
		60	Modified Henderson–Pabis	a = 2.3774	0.9968	0.0244
				b = 0.0002
				c = −1.3318
				k = 0.0004
		70	Modified Henderson–Pabis	a = 1.2807	0.9942	0.0290
				b = 4.284410^−5
				c = −0.2056
				k = 0.0010
		80	Modified Henderson–Pabis	a = 1.1584	0.9934	0.0274
				b = 1.751110^−5
				c = −0.0747
				k = 0.0017