Characteristics of ammonia emission during thermal drying of lime sludge for co-combustion in cement kilns

Liu, Wei; Xu, Jiang; Liu, Jia; Cao, Haihua; Huang, Xiangfeng; Li, Guangming

doi:10.1080/09593330.2014.942705

Cited by 20 publications

(4 citation statements)

References 26 publications

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“…Another issue regards the effect of the environmental conditions on the final energy use: the analysis of Reference [10] reveal the drying chamber as particularly susceptible to the external temperature; its performance deteriorate with temperature fluctuations of approx. 5 • C. Finally, some specific applications such as the convective drying of biomass and hazardous materials, release several pollutants into the atmosphere; this deteriorates local air quality and contributes to greenhouses gas emissions [11][12][13]. For such reasons, stringent environmental regulations limit their functioning.…”

Section: Introductionmentioning

confidence: 99%

Off-Design Exergy Analysis of Convective Drying Using a Two-Phase Multispecies Model

Aquino

Poesio

2021

Energies

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The design of a convective drying cycle could be challenging because its thermodynamic performance depends on a wide range of operating parameters. Further, the initial product properties and environmental conditions fluctuate during the production, affecting the final product quality, environmental impact, and energy usage. An off-design analysis distinguishes the effects of different parameters defining the setup with the best and more stable performance. This study analyzes a reference scenario configured as an existing system and three system upgrades to recover the supplied energy and avoid heat and air dumping in the atmosphere. We calculate their performance for different seasons, initial product moisture, input/output rate, and two products. The analysis comprises 16 simulation cases, the solutions of a two-phase multispecies Euler–Euler model that simulates the thermodynamic equilibrium in all components. Results discuss the combination of parameters that maximizes the evaporation rate and produces the highest benefits on global performance up to doubling the reference levels. The advantages of heat recovery vary by the amount of wasted energy, increasing the exergy efficiency by a maximum of 17%. Energy needs for air recirculation cut the performance at least by 50%. Concluding remarks present the technical guidelines to reduce energy use and optimize production.

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Section: Introductionmentioning

confidence: 99%

Off-Design Exergy Analysis of Convective Drying Using a Two-Phase Multispecies Model

Aquino

Poesio

2021

Energies

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“…Many studies on adding lime-dried sludge in cement production have been conducted in recent years [6][7][8][9]. Since the basic chemical compositions of lime-dried sludge (mainly including CaO, Al 2 O 3 , Fe 2 O 3 and SiO 2 ) in cement production are very close to the traditional raw materials, lime-dried sludge can partially replace raw materials in the production of cement.…”

Section: Introductionmentioning

confidence: 99%

Feasibility and Carbon Footprint Analysis of Lime-Dried Sludge for Cement Production

Zhao

Lin

et al. 2020

Sustainability

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Cement manufacturing and the treatment of sludge are considered both energy-intensive industries and major greenhouse gas (GHG) emitters. However, there are still few studies on comprehensive carbon footprint analysis for adding municipal sludge in the cement production. In this study, the lime-dried sludge blended with calcium oxide at the mass mixing ratio of 10% was utilized as raw material for the preparation of Portland cement. The chemical and physical properties of sludge were analyzed. A set of carbon footprint calculation methods of lime-drying treatment of sludge and reuse in cement kilns was then established to explore the feasibility of coprocessing lime-dried sludge in cement kilns. The results showed lime-dried sludge containing CaO, SiO2, Al2O3, and Fe2O3 was ideal for cement production as raw material. However, the water content of lime-dried sludge should be strictly limited. The lime-drying process presented the biggest carbon emission (962.1 kg CO2-eq/t sludge), accounting for 89.0% of total emissions. In the clinker-production phase, the lime-dried sludge as raw material substitute and energy source gained carbon credit of 578.8 and 214.2 kg CO2-eq/t sludge, respectively. The sludge used for producing cement clinker could reduce carbon emissions by 38.5% to 51.7%. The addition ratio of lime and stacking time in the sludge lime-drying process could greatly affect the carbon footprint of coprocessing lime-dried sludge in cement kiln.

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“…In the past, sludge drying installations have experienced fires and explosions. Some sludge dryers operate at high temperatures (.100°C) which promotes the emission of malodorous gases and volatile compounds (Deng et al 2009;Ding et al 2015;Liu et al 2015;Weng et al 2015;Zheng et al 2017;Wu et al 2018), presenting yet another emissions abatement burden. Modern sludge drying plants must be fitted with appropriate exhaust gas cleaning equipment, which can represent significant additional capital cost.…”

Section: Introductionmentioning

confidence: 99%

Heat pump drying of industrial wastewater sludge

Yuan

Chu²

2020

Water Practice and Technology

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The popularity of heat drying of wastewater sludge has increased over the past several years because it can reduce sludge mass and volume, and hence disposal costs. However, drying sludge using conventional combustion-heated dryers is energy-intensive. Heat pump dryers can be efficient and offer significant energy savings by recycling the drying heat. This paper describes a heat pump dryer designed for continuous drying of industrial wastewater sludge. The dryer constructed was essentially a closed-loop air system. The air used for drying is dehumidified to recover the latent heat of vaporization, re-heated using the recovered heat, and recirculated in a closed environment. The closed-loop layout eliminates emissions of dust, malodorous gases, and volatile compounds, obviating the need for exhaust treatment otherwise required to meet environmental regulations. Data on the moisture extraction rate, specific moisture extraction rate, and specific energy consumption are presented and discussed.

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Characteristics of ammonia emission during thermal drying of lime sludge for co-combustion in cement kilns

Cited by 20 publications

References 26 publications

Off-Design Exergy Analysis of Convective Drying Using a Two-Phase Multispecies Model

Off-Design Exergy Analysis of Convective Drying Using a Two-Phase Multispecies Model

Feasibility and Carbon Footprint Analysis of Lime-Dried Sludge for Cement Production

Heat pump drying of industrial wastewater sludge

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