Cradle to Gate
Identity ID
08c2a76c-c95b-45bb-9928-c05d85cce144
Waste treatment
Associated ID
6369aaad-3bf6-465a-9779-f1ab809c60d8
Included activities starts
Included activities ends
Description
kitchen waste is not suitable for separate incineration. The data source is a municipal solid waste (MSW) mechanical grate incineration plant in Ningbo City, where kitchen waste is co-incinerated with other wastes. The waste incineration power generation process includes a garbage bunker, incinerators, waste heat boilers, and turbo-generators, supplemented by supporting systems such as a flue gas purification system, ash/slag treatment system, and leachate treatment system.
First, the waste is stored in a negative-pressure garbage bunker for 5–7 days of fermentation and dewatering to increase the calorific value of the feedstock. After fermentation, the waste is fed into the incinerators by mechanical grabs for combustion. The plant is equipped with three mechanical grate incinerators, each with a processing capacity of 750 t/d, enabling a total daily MSW treatment capacity of 2250 t.
High-temperature flue gas generated from waste incineration is sent to waste heat boilers for heat recovery and steam production, which drives two 25 MW steam turbines and two 30 MW generators to generate electricity. The daily power output reaches 8.3×10⁵ kWh, which is fed into the power grid. The flue gas from incineration enters the purification system, with main pollutants including CO, SO₂, NOₓ, HCl, and dioxins. The plant adopts a combined purification process: "SNCR + semi-dry Ca(OH)₂ spray deacidification + dry Ca(OH)₂ deacidification + activated carbon adsorption + baghouse filter + SGH + SCR + wet deacidification + GGH". The purified flue gas is discharged into the atmosphere through the chimney, and the final pollutant concentrations comply with the EU Industrial Emissions Directive 2010 (EU 2010/75/EC) and the national Standard for Pollution Control on Municipal Solid Waste Incineration (GB 18485-2014).
The incineration products include bottom ash and fly ash. Bottom ash accounts for 20% of the MSW input, which is transported for comprehensive utilization as building materials. Fly ash accounts for 2.2% of the MSW input, which is transported to landfills for disposal.
Given that the incineration flue gas volume is positively correlated with the received base low heating value (LHV) of the fuel, for simplification, this study calculates the flue gas volume and power generation based on the received base LHV of kitchen waste and other wastes. The required ammonia water, slaked lime, activated carbon, and pollutant emissions are also simplified in proportion. The average wet-based LHV of the input kitchen waste and other wastes is 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.