Methane generation system and methane generation method

A methane generation system that generates methane from a first gas containing methane and carbon dioxide generated by treatment of wastewater in a wastewater treatment facility, the methane generation system comprising:

• a first flow rate regulator configured to regulate a flow rate of the first gas;
• an ammonia recovery device configured to recover ammonia contained in a separated liquid discharged from the wastewater treatment facility;
• a methane generation reactor configured to generate methane, water, and nitrogen by causing the first gas that has passed through the first flow rate regulator to react with a fourth gas containing the ammonia supplied from the ammonia recovery device;
• a second flow rate regulator disposed in a flow path of the fourth gas to the methane generation reactor and configured to regulate a flow rate of the fourth gas;
• an inlet sensor assembly configured to measure an amount of carbon dioxide in the first gas before the first gas is supplied to the methane generation reactor;
• an outlet sensor assembly configured to measure at least one of an amount of unreacted ammonia and a concentration of carbon dioxide in a gas discharged from the methane generation reactor;
• and
• a controller including a processor and a memory storing a computer-executable instruction, wherein
• the processor is configured to execute, by executing the instruction stored in the memory, (a) an operation of calculating a reference supply amount of the ammonia to be supplied to the methane generation reactor based on an amount of carbon dioxide in the first gas measured by the inlet sensor assembly, and (b) an operation of regulating at least one of a supply amount of the first gas by the first flow rate regulator and a supply amount of the ammonia by the second flow rate regulator in real time based on a measurement result by the outlet sensor assembly.

A methane generation method for generating methane from a first gas containing methane and carbon dioxide generated by treatment of wastewater in a wastewater treatment facility, the method comprising:

• measuring an amount of carbon dioxide contained in the first gas using an inlet sensor assembly;
• calculating a reference supply amount of a third gas containing necessary hydrogen based on the measured amount of carbon dioxide using a controller;
• causing, in a methane generation reactor, the first gas supplied via a first flow rate regulator to react with the third gas supplied via a second flow rate regulator based on the reference supply amount to generate a second gas containing methane;
• monitoring, using an outlet sensor assembly, a concentration of at least one of carbon dioxide and hydrogen in the second gas generated;
• and
• regulating, using the controller, at least one of a flow rate of the first gas by the first flow rate regulator and a flow rate of the third gas by the second flow rate regulator in real time based on the monitored concentration.