Gas engine electric power generating system effectively utilizing greenhouse gas emission credit
A gas engine electric power generating system in which an electric power generating apparatus including an electric power generator connected with a gas engine of a pilot fuel oil ignition type is installed near a coal mine. Recovered methane gas and ventilated methane gas from the mine are introduced into a cylinder of the gas engine while being adjusted to be introduced as a lean methane/air mixture to operate the engine to produce electric power. A carbon dioxide emission credit reflecting the difference in greenhouse effect index between releasing coal mine methane gas to the atmosphere and releasing the methane gas to the atmosphere as carbon dioxide, is registered on an emission credit market. Also included are the affiliated systems of mutual patronage relation constituted by one or a plurality of the systems and nearby power generating system or systems using coal bed methane or pre-mining gas as fuel.
1. A gas engine electric power generating system comprising:
an electric power generating apparatus including an electric power generator coupled to a pilot fuel oil ignition type gas engine having at least one cylinder and a cylinder pressure detector;
a combustion diagnosis apparatus for diagnosing a combustion condition within the gas engine in response to a cylinder pressure detector signal;
a combustion controller that adjusts a fuel mixture comprising recovered methane gas having a methane concentration of 30-50% and ventilated methane gas having a methane concentration of 0.3-0.7% in the gas engine in response to a combustion condition signal from said combustion diagnosis apparatus; and
a gas injection device that provides the fuel mixture for introduction into the cylinder while mixing the recovered methane gas and the ventilated methane gas to define a lean methane/air mixture having a methane concentration of 3-5% and having an air excess ratio not less than 2, such that the gas engine operates to produce electric power.
2. A gas engine electric power generating system in accordance with claim 1 wherein said combustion controller adjusts the fuel mixture by comparing a maximum pressure ratio defined as P p /P o against predetermined pressure ratios each corresponding to at least one of a plurality of diagnoses, where P p is a maximum cylinder pressure in a cycle and P o is a compression pressure for at least one predetermined crank angle in a compression stroke, to facilitate preventing engine knock and engine misfire.
3. A gas engine electric power generating system in accordance with claim 1 further comprising a coal mine that supplies the recovered methane gas and the ventilated methane gas.
4. A gas engine electric power generating system, said system comprising:
an electric power generator coupled to a pilot fuel oil ignition type gas engine having at least one cylinder and a cylinder pressure detector;
means for diagnosing a combustion condition within the gas engine in response to a signal from the cylinder pressure detector;
means for adjusting a fuel mixture of recovered methane gas having a methane concentration of 30-50% and ventilated methane gas having a methane concentration of 0.3-0.7% in the gas engine in response to a combustion condition signal from said means for diagnosing a combustion condition; and
means for introducing the fuel mixture into the cylinder while mixing the recovered methane gas and the ventilated methane gas to define a lean methane/air mixture having a methane concentration of 3-5% and having an air excess ratio not less than 2.
5. A gas engine electric power generating system in accordance with claim 4 wherein said means for adjusting the fuel mixture further comprises comparing a maximum pressure ratio defined as P p /P o against predetermined pressure ratios each corresponding to at least one of a plurality of diagnoses, where P p is a maximum cylinder pressure in a cycle and P o is a compression pressure for at least one predetermined crank angle in a compression stroke, and facilitates preventing engine knock and engine misfire.
6. A gas engine electric power generating system in accordance with claim 4 further comprising a coal mine that supplies the recovered methane gas and the ventilated methane gas.