New Strategy toward Household Coal Combustion by Remarkably Reducing SO₂ Emission

Abstract

A large amount of sulfur dioxide (SO2) will be released during rural household coal combustion, causing serious environmental pollution. Therefore, it is very urgent to develop a clean and efficient fuel to substitute rural household coal controlling SO2 emission. In this paper, a new strategy toward scattered coal combustion with remarkably reducing SO2 emission was proposed. Coal and compound additive of Al2O3 and CaCO3 were blended and then copyrolysis at 1050 °C was performed to produce clean coke. First, the sulfur content of clean coke was reduced, meanwhile, generating sulfur fixation precursor during pyrolysis. Then, clean coke is used for efficient sulfur fixation during the subsequent combustion process to reduce SO2 emissions. The effects of combustion temperature, Al/S molar ratio, and the mechanism of sulfur retention during clean coke combustion were studied in the tube furnace and muffle furnace. The mechanism can be attributed the following reason: (a) CaS produced during pyrolysis and CaO decomposed by complex additives were oxidized during combustion, and CaO captured the SO2 released from clean coke combustion, which formed CaSO4. (b) CaSO4 reacts with Al2O3 to produce calcium sulfoaluminate at high temperatures, which improves the sulfur fixation efficiency of clean coke combustion at high temperatures. In a word, this new strategy can greatly reduce the emission of SO2, thus helping to solve rural household coal pollution problems.

Effects of Vitrinite in Low-Rank Coal on the Structure and Combustion Reactivity of Pyrolysis Chars

“…41 In 1989, Knight and White (KW) studied a variety of carbon materials and obtained an empirical formula L a (nm) = 4.4(I D / I G ) −1 for calculating L a , hereinafter referred to as the KW formula. 42 Cancado et al systematically studied the relationship between the I D /I G and L a of the Raman spectra at different excitation wavelengths (λ 1 = 647.0, 568.0, 514.5, 488.0, and 457.9 nm) and obtained the empirical formula L a (nm) = (2.4 × 10 −10 )λ 1 4 (I D /I G ) −1 . 4343 Baldan et al calculated the L a of vitreous carbon using the KW, Cancado, and Bragg formulas.…”

“…Low-rank coal has an abundance of reserves, a high moisture content, and a low calorific value. , The direct combustion of low-rank coal generates a low utilization rate and environmental pollution. , The development of clean coal technology is of great significance to improve the utilization efficiency of low-rank coal and reduce environmental pollution. Pyrolysis is a highly promising technology in clean coal technology as it can produce high-value chemicals from coal .…”

Thermodynamic research on the effect of CaO on the transformation of arsenic and sulfur in coal in different pyrolysis atmospheres

“…Even though there are numerous pieces of literature about the effect of Ca on arsenic 2,4,23,28 or sulfur [34][35][36][37][38] separately, there are not too many papers about the effect of Ca on arsenic and sulfur together. The current related literature includes experimental work, 6,11,21,39 thermodynamic equilibrium calculation, 40 and kinetic behavior.…”

Boosting SO2 Capture within Nitrogen-Doped Microporous Biocarbon Nanosheets

“…1−3 According to statistics, in 2017, coal consumption reached 490 million tons, and bulk coal consumption was nearly 7.55 billion tons, of which 234 million tons were used for fuel burning of household stoves. 4 To address this issue, the removal of SO 2 by adsorption-based techniques has been reported, 5,6 and highperformance adsorbents are usually required due to the relatively low partial pressure of SO 2 in the flue gas. Although some desulfurization techniques are already available for SO 2 capture, 7−9 such as wet desulfurization processes based on calcium-containing chemical adsorbents, they are restricted by high costs and inherent disadvantages, including the nonregenerative nature and the formation of byproducts (e.g., calcium sulfate).…”

“…The extensive emission of acid gases, such as SO 2 and CO 2 , into the atmosphere threatens the biological environment and human health, where ∼73% of the total SO 2 is released from point sources such as coal-fired power plants. − According to statistics, in 2017, coal consumption reached 490 million tons, and bulk coal consumption was nearly 7.55 billion tons, of which 234 million tons were used for fuel burning of household stoves . To address this issue, the removal of SO 2 by adsorption-based techniques has been reported, , and high-performance adsorbents are usually required due to the relatively low partial pressure of SO 2 in the flue gas.…”