Question

Question 1 Over a 3 year period, waste from a population of 100,000 has been placed in a sanitary landfill with a gas recovery system. This practice is to continue into the foreseeable future, so a steady supply of gas CH4 is expected. A nearby armed forces base has a 50 oil-heated detached houses for married personnel. The homes use an average of 100 X 100 kJ of heat energy during the year and have peak demand during the coldest month 3 times the average (a) Will there be enough landfill gas available to heat these homes? [20 marks] (b) Give your opinion on the advantages of using this gas for space heating? Consider the economics on recovery, storage, etc for 50 homes. Consider the environmental impacts of using and not using this gas. [6 marks] Assumptions: Quantity of municipal solid waste delivered to site 1 tonne /capita per year. Total gas production 200L CH4 per kg of refuse over 30years. Gas recovery will be at least 15% of that generated, i.e. 30L CH4 per 1 kg of refuse. At least one-third of this gas will be generated within the first 5 years. Conversion efficiency of the gas furnaces is 75%. The first year the homes are connected will be the most critical since the gas available will be dependent on the 3 year supply of waste already in place. This amount of waste will therefore be used as the basis for the calculations. Given: o CH4 810KJ/mol (combustion energy) o PV=nRT at STP (ideal gas equation), given R= 0.0825 L.atmKmol1

Please do question 1 neatly

Answer 1

: /0000OX tom To tal guanty HSW did 3 00000 ton nes 3 60000 3 X = 2001 CN pei a auer 30 yeAy 20 L aver 20 x 3 X/o o tat gas 0duced Gx 10L. 17 6x109 Be- 90 X167 = 9 X/0 L in 5 years. gadprodeed 1yar 3 yeor Net gas fredued 10L - 18 X(03L

Convension heat emere : 75X Require ne ent ke pryprsou nel houses :- 6 Nat encrgyO/ 00 x /0 9 caldect 15 X/0 KJ. S x/0 k Peak heat onenyy I8X/07 L Amount of as po duced Pr: nRT O.0825 R=AL atm Kmol 7: 273 L Platn at STP at STP

1X ) 8 X)0 L 2a3 ( X/0 n 73 x 0.08 7992 O079 t mol ginen 810KJ/mo l Meat emeyy ducrodl 7992 00 99X1O KJ 647 3 52 6 473.5 KJ. 64 thon Ahei Thus, much ralue amounty Aeat ti'mes 5 X/06 KS peah at an albunolance Vans a is Yes, tHere ygand fil anailabk homas these heat