## 1 Introduction  
With the development of economy and society, the urbanization process has accelerated and residents' living standards have been improved in China. Yet municipal solid waste management (MSWM) has become a pronounced problem because of the population concentration and increased consumption during urbanization [1]. More than one-third of the cities and towns have fallen into the predicament of garbage siege and have been surrounded by landfills [2], which seriously hinders the sustainable development of society. During the 10 years from 2010 to 2019, the volume of municipal solid waste (MSW) removal rose from 158 million tons a year to 242 million tons a year in China [3]. Besides, population explosion and rapid urbanization have also brought about the rapid growth of MSW in urban areas worldwide. Global MSW may increase by 0.9 billion tons from 2010 to 2025 [4]. In particular, the urban population of East Asia and Pacific region is much higher than other regions, and the per capita MSW production rate could increase by 60% from 2012 to 2025 [5]. The garbage growth rate is commonly higher than the urbanization rate, and the garbage is piled up around cities and towns, causing environmental pollution and landscape deterioration. Consequently, appropriate MSWM is an urgent and vital task in China and critical to the world's sustainable development. MSWM includes biological treatment and chemical treatment methods, of which biological treatment technologies cover landfilling, digestion and composting and chemical treatment technologies comprise incineration, gasification and pyrolysis. Nevertheless, to date, landfilling and incineration are still the prime methods in most countries [6]. Several reasons can be summarized: One is that a part of biological treatment technologies take a long time and there are many problems to be solved [7]; another is that most developing countries take economy and technology into account, and they still prefer landfilling when land resources are available [8]; the last is that waste incineration plants occupy small area and recover energy while reducing waste, which is better than other waste treatment methods [9]. According to the changes in the number of the newly added MSW harmless treatment plants in China from 2015 to 2019 [3], the proportion of MSW incineration plants has increased rapidly in the total MSW treatment plants while the number of MSW landfills no longer augments after 2015. Cities have been surrounded by landfills and improper filtrate treatment issues occur in them, which can partly explain the upsurge of MSW incineration treatment plants in China [2;10]. Moreover, since fossil fuels account for a relatively high proportion of the global primary energy, waste incineration technology not only treats a large amount of waste but also recovers its energy to offset part of the consumption of fossil fuels [11]. However, compared with conventional coal-fired power units (CFPUs), the energy efficiency of waste-to-energy units (WTEUs) is lower due to lower steam parameters, higher condensing pressure, higher auxiliary power consumption rate and more exhaust flue gas energy loss. The current behaviors to enhance the energy efficiency of WTEUs mainly focus on raising steam parameters and utilizing exhaust flue gas heat. The live steam temperature and pressure in waste-to-energy (WTE) boilers are usually designed at 400 \({}^{\circ}\)C and 40 bar, respectively [12]. Raising steam parameters can recover more energy of MSW and enhance power efficiency, while the high-temperature flue gas produced by MSW incineration could cause high-temperature corrosion of heat exchangers in WTE boilers [13;14]. [PERSON] et al. [4] introduced a new type of refractory brick to the combustion chamber, which delivers more heat, allows steam to superheat on waterwall, reduces corrosion risks and increases the WTEU efficiency. [PERSON] et al. [15] arranged an anti-corrosion radiation superheater (SH) in the high-temperature flue gas area to achieve higher steam temperature.