Cradle to Gate
Identity ID
623285a3-2d79-4c9d-a2f9-9c8b03fefd48
Waste treatment
Associated ID
6369aaad-3bf6-465a-9779-f1ab809c60d8
Included activities starts
Included activities ends
Description
kitchen waste is not suitable for standalone incineration. The data source is a municipal solid waste mechanical grate incineration plant in Ningbo City, where kitchen waste is co-incinerated with other waste. The waste-to-energy incineration process includes a waste storage pit, incinerator, waste heat boiler, and steam turbine generator, along with associated systems for flue gas purification, ash and slag handling, and leachate treatment. The waste is first stored in a negatively pressured waste storage pit for 5--7 days to undergo fermentation and dewatering, thereby increasing its calorific value prior to combustion. After fermentation, the waste is fed into the incinerator using mechanical grabbers. There are three incinerators in total, all of which are mechanical grate furnaces with a capacity of 750 t/d, enabling a total daily municipal solid waste processing capacity of 2,250 t. The high-temperature flue gas generated from waste incineration is used in waste heat boilers to recover thermal energy and produce steam, driving two 25 MW steam turbine units and two 30 MW generator units to generate electricity, with a daily electricity output reaching 8. 3*10^5 kWh of electricity is delivered to the grid. The flue gas generated from incineration enters the purification system, with main pollutants including CO, SO2, NOx, HCl, dioxins, etc. The plant employs a process combining 'SNCR + semi-dry acid gas removal using Ca(OH)2 spray + dry acid gas removal using Ca(OH)2 + activated carbon adsorption + baghouse filter + SGH + SCR + wet acid gas removal + GGH'. The cleaned flue gas is then released into the atmosphere via a chimney, with final pollutant concentrations meeting the requirements of the EU Industrial Emissions Directive 2010 (EU 2010/75/EC) and China's National Standard for Pollution Control of Municipal Solid Waste Incineration (GB 18485-2014), being below the specified emission limits. The products after incineration include bottom ash and fly ash. The amount of bottom ash generated is 20% of municipal solid waste, which is transported to comprehensive utilization facilities for recycling into construction materials, and the amount of fly ash generated is 2% of municipal solid waste. 2%, transported to landfill disposal. Given that the flue gas volume from incineration is positively correlated with the gross lower heating value of the fuel, for simplification, this study calculates the flue gas volume and electricity generation based on the gross lower heating values of kitchen waste and other waste, respectively. Quantities of auxiliary materials such as ammonia water, slaked lime, activated carbon, and pollutant emissions are also proportionally simplified. The average wet-based lower heating values of the input kitchen waste and other waste are 2100 kJ/kg and 8049.57 kJ/kg, respectively.
Activity Description
Municipal solid waste incineration plants typically adopt co-incineration processes to treat various types of waste, including kitchen waste. Waste is first fermented in sealed chambers to increase its calorific value, and then fed into the incinerator by mechanical devices. The incinerator burns the waste at high temperatures, and the generated thermal energy is converted into steam by a waste heat boiler, which drives the generator for electricity production. Flue gas undergoes a series of purification steps, including acid removal, adsorption, and dust removal, to reduce pollutant emissions. The bottom ash after incineration can be recycled, while fly ash is safely landfilled. Throughout the process, the flue gas volume and power generation are calculated based on the waste's calorific value to ensure treatment efficiency and compliance with environmental standards.
Process Description
kitchen waste on a dry basis: average organic matter content of 80–100%, crude protein 14–30%, and crude fat 15–30%; on a wet basis: moisture content 70–90%, oil content 3%, and salt content 1%.
Time period
2022
2026
Geography
China
Macroeconomic value
Business-as-Usual
Data validation
Yes
Technology
Current Technology
Technology comment
Waste-to-energy incineration is a process in which municipal solid waste is thoroughly combusted at high temperatures of 850--1100 °C, generating high-temperature flue gas. This flue gas transfers heat in a waste heat boiler to produce superheated steam, which then drives a steam turbine generator to produce electricity. Waste-to-energy incineration is a mature solid waste treatment technology. kitchen waste is typically mixed with other wastes and incinerated for emission reduction, achieving volume reduction of more than 85%. The method is simple and highly efficient, and the thermal energy generated can be further utilized by converting it into steam and electricity. However, the high moisture content of kitchen waste affects the incineration calorific value; direct incineration can impact the stable operation of incinerators, typically requiring pre-dewatering and addition of auxiliary fuel, and may generate harmful gases such as dioxins.