MS Thesis: Pre–feasibility study of a waste–to–energy (WTE) plant for Baotou city, China
By Zucheng Guo
Advisors: Nickolas J. Themelis and A.C. Bourtsalas
Department of Earth and Environmental Engineering
Fu Foundation School of Engineering & Applied Science
Columbia University
April 2015
With the rapid development of economy and population growth in China, the “garbage siege” problem has affected many Chinese cities. Baotou is one of these cities, in the province of Inner Mongolia. In 2014, the generation of MSW was 0.626 million tons, i.e., about 1715 tons/ day. In Baotou city, there is only one Waste–to–Energy plant and two landfill sites. An estimated 58% of municipal solid waste is disposed by landfilling, which causes secondary pollution and a loss of potential energy.
Compared with landfills, the waste–to–energy technology significantly reduces the volume of the waste to be disposed and produces electricity; it also avoids the emission of methane to the atmosphere and the contamination of groundwater and soil. The WTE technology can also solve the problem of the scarcity of urban land for landfills and conserve arable land in China. This technology is very mature and has been adopted in more than 50 countries.
Based on the development of WTE technologies and the operating experience in China, this study compared two major WTE technologies: moving–grate (MG) and the circulating fluidized bed (CFB), and finally recommends the latter for implementation in Baotou city. At present, China is at the advanced level in the use of fluidized bed combustion technology for burning low calorific value fuel worldwide. The project evaluated for Baotou city is a three–line CFB WTE plant of total capacity of 1500 tons/day.
The generating capacity of the Baotou Power Grid must be increased by at least 400 MW by 2020. Therefore, the power to be generated by the WTE plant, estimated at about 20 MW, will be welcome.
Next to the furnace and boiler, the air pollution control(APC) system is a vital part of a WTE plant. The system recommended for the Baotou WTE consists of semi–dry scrubbing by Ca(OH)2, NO2 control by ammonia injection, activated carbon injection for dioxin an volatile metal control, and fabric filter baghouse, for capturing particulate matter. Nearly all new WTE plants, in China and other coutries, are provided with such high–efficiency APC systems.
From the economic aspect, implementing a new waste to energy (WTE) plant in Baotou will be a good investment. The capital investment of the 1,500 ton/day plant was estimated at US$80 million (US$183 per ton of annual capacity at 80% plant availability). Of this amount, US$56 million will be provided by a loan from the local bank at 6.5% interest and US$24 million dollars from private investment. It was ascertained that the local government will pay a gate fee of US$9.56 per ton of MSW processes at the plant and the Baotou grid will purchase the power generated at the price of US$100 per MWh