Producing Effective and Clean Coke for Household Combustion Activities to Reduce Gaseous Pollutant Emissions

Abstract

Nowadays, the gaseous pollutant emissions, including particulate matter (PM), sulfur dioxide (SO2), and nitrogen oxide (NOx) from household coal combustion, cause great threat to environment and public health by contributing to severe haze in China. Particularly, a clean coke free of the major pollutants precursors (sulfur and nitrogen compounds) by sulfur fixation and denitrification has been deemed as an effective strategy to reducing pollutants. In this paper, a preprocessed coke was prepared by co-pyrolysis of high-sulfur coal with the assistance of calcium-based and iron-based complexes at high temperature. The results show that high-temperature co-pyrolysis could remove the volatile compounds that are major precursors for the formation of gaseous pollutants from the raw coal. During the coking process, the sulfur can be removed by being fixed in the form of CaS in presence of a Ca-based complex, which could be beneficial for the CaSO4 during the coke combustion. The volatile nitrogen is transferred to the gas phase with the addition of Fe-based complexes, which effectively reduce the residual nitrogen in coke. As a result, Ca-based additives captured the released SO2 and formed CaSO4 during the combustion process. In addition, in the presence of Fe-based complexes, both char and CO react with NOx to form N2, which leads to a reduction in NOx emissions during combustion. Additionally, the replacement of current residential coal with a new type of clean coke is a facile method for reducing gaseous pollutant emissions from household activities to protect the atmospheric environment. The average emission factors (EFs) of PM, SO2, and NOx for the prepared clean coke were small during combustion and were much lower than the EFs of the tested raw coal, semicoke, and briquettes.

Environmental Effective Assessment of Control Measures Implemented by Clean Air Action Plan (2013–2017) in Beijing, China

“…However, Beijing gradually changed its management style by adjusting the energy structure. Coal use, with its high pollution intensity [21][22][23][24], was gradually decreased as a proportion of total energy use from 22.1% in 2012 to 4.8% in 2017, essentially achieving coal-free status. In contrast, clean energy use, such as natural gas, amounted to 29.4% of total energy use in 2017.…”

Clean Preparation of Formed Coke from Semi-coke by the Carbonated Consolidation Process

“…The formed cokes have a much lower SO 2 emission concentration than coal bituminous. Furthermore, adding Ca­(OH) 2 significantly reduces the SO 2 emission concentration and achieves the function of sulfur fixation and emission reduction because SO 2 produced by combustion can react with CaO, with most of it eventually fixed in the form of CaSO 4 …”

“…Thus, the clean utilization of low-rank coal has become a priority for China to control environmental pollution. 3,4 Currently, the primary method for the clean utilization of low-rank coal is through coal pyrolysis, which produces various products such as coal pyrolysis gas, semi-coke, and coal tar. 5,6 With the increasing adoption of clean coal utilization technologies, the semi-coke industry has experienced significant growth.…”

“…13 Given the depletion of coking coal resources, the increasing price of metallurgical coke, and the maturing pyrolysis technology for raw materials such as low-rank coal and biomass, technologies for formed coke production have received significant attention and become hotspots in current scientific research. 4,13,14 T h i s c o n t e n t i s The cold-pressed coke-forming process using binders has emerged as the dominant application and subject of research in this field, owing to several advantages such as its simple process, low temperature, low-pressure requirements, and versatility in utilizing various raw materials. 15 Binders play a crucial role in the coke-forming process by reducing viscosity, fixing sulfur on raw coal, and optimizing the quality of raw coal.…”

A systematic review on mitigation of common indoor air pollutants using plant-based methods: a phytoremediation approach

“…Inorganic air pollutants are carbon monoxide (CO), carbon dioxide (CO 2 ), ozone (O 3 ), nitrogen oxides (NOx), and sulfur dioxide (SO 2 ) (Liu et al 2019). Anthropogenic activities such as greenhouses, garages, ventilated kitchens, and the combustion of fossil fuels (ovens, stoves, heaters, and tobacco smoke) produce gases such as CO 2 and CO; however, these gases are naturally produced by natural sinks such as forests, wetlands, and the sea (Weyens et al 2015).…”