Estimate the energy content of solid waste sample with the composition given in a table below. What is the content on dry basis and ash free dry basis?

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written 8.8 years ago by

teamques10 ★ 69k

• modified 8.8 years ago

Assume 100 kg of sample.

Component	% by mass	Energy KJ/kg	Total Energy (KJ)
(1)	(2)	(3)	(4) (2*3)
Paper	45	4650	753750
Cardboard	10	16750	163000
Plastics	10	16300	326000
Food wastes	15	32600	69750
Garden wastes	10	6500	65000
Wood	5	18600	93000
Tin cans	5	700	3500
-	100 %	-	1474000KJ

1) Unit Energy Content $= 1474000/100 \\ =14740 KJ/kg$

2) Energy content on dry basis:

Component	% by mass	Moisture content	Dry content,(100-m)%	Total mass
(1)	(2)	(3)	(4)	(5) (4*2)
Paper	45	6	94	42.3
Cardboard	10	5	95	9.5
Plastics	10	2	98	9.8
Food wastes	15	70	30	4.5
Garden wastes	10	60	40	4
Wood	5	20	80	4
Tin cans	5	3	97	4.85
-	100 %	-	-	78.95

Moisture content $= (100-78.95/100)*100 \\ =21.05%$

Energy on dry basis $= (100*14740/100-21.05) \\ =18670.04 KJ/kg$

3) Energy on ash free dry basis:

Assume ash content =5%

Energy content $= (100*14740/100-5-21.05) \\ = 19932.38KJ/kg.$

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