Convegni ATI - Accesso riservato soci CTI

Autore: I.M. Smith

Collana: AA - 1996 Milano - Effetto serra: tecnologia e legislazione

Note:
Greenhouse gas emissions from coal are primarily CO2 with some CH4, and N2O. CO2 emissions from coal utilisation amount to about one third of the CO2 emission from human activities. CH4 is mainly emitted from coal production rather than from its use and comprises about 8% of CH4 emissions while N20 emissions from coal combustion account for about 5% of N20 emissions (both related to emissions from human activities). There are many technologies which may be deployed to reduce greenhouse gas emissions. The first step is to increase the efficiency of power generation. Advanced power generation has the potential to reduce emissions by about 20-30% compared to the global net plant efficiency which averages 36% (LHV). Cogeneration of heat and power offers a means of recovering heat from the steam cycle and further improving the total plant efficiency. It seems possible to reduce CO2 emissions by about 60% by efficiency improvements. For greater CO2 reductions, there are capture and disposal technologies which generally incur considerable energy penalties and costs. The CO2 capture methods include absorption using amines, adsorption, cryogenics and membrane separation. For CO, disposal the largest potential sink is the ocean, with a potential capacity of 73 million Gt CO2. Other potential sinks with an estimated capacity of 150 - 520 Gt CO2 are aquifers, natural gas fields, oil fields, and forestry.