The landfill gas (or the biogas) is formed as a result of solid municipal waste (MSW) disposal. The biogas consists mainly of methane (CH4) and carbon dioxide (CO2). The ratio of these gases fluctuates in a fairly wide range but is mainly in the range of 60-70% СН4 and 30-40% СО2. At the same time, the biogas generation lasts tens of years after the closure of landfills thereby having a negative impact on the environment for a long time.
Modern landfills are complex engineering structures equipped, in particular, with a biogas collection and removal system. This system is a set of perforated pipes located in the landfill body at a depth of 10 - 25 meters vertically or horizontally and interconnected by a unifying manifold. The selected biogas passes sequentially through a moisture separator, a separator of organic and other impurities and a compressor is supplied either to an internal combustion engine or to a boiler room. When the biogas is burned energy is generated which ensures the operation of the generator. The generated electricity is supplied to the power grid or used for the company's own needs. The additional heat energy is generated when using a boiler room, but the installation scheme becomes more complicated.
30 - 40% of carbon dioxide originally contained in biogas as well as biogas combustion products containing up to 7% of carbon dioxide enter the atmosphere because of emission in the presented variant of biogas utilization. Thus, this scheme of biogas utilization is not perfect from an environmental point of view and requires improvement.
The authors propose to install a system for extracting carbon dioxide from biogas for example by chemisorption (monoethanol purification) after the separator of organic and other impurities in order to eliminate this drawback. The carbon dioxide is proposed to be further used as a raw material in the food industry, microbiology, medicine, metallurgy and other areas of the national economy.
At the same time, the biogas freed from the carbon dioxide containing up to 98% methane:
1) is supplied to gas networks as fuel for gas turbines in order to obtain electrical and thermal energy;
2) is used as fuel for refueling vehicles running on methane (production of gas motor fuel from methane gas hydrates);
3) is used as carbon food in the production of a protein-vitamin supplement (gaprin) containing up to 75% of complete protein.
|Position of speaker||Ph.D. candidate|
|Publication||International journal «Resource-Efficient Technologies»|
|Affiliation of speaker||Klevanova Elena|