Cement Facility Research Articles

Impacts of alternative fuel combustion in cement manufacturing: Life cycle greenhouse gas, biogenic carbon, and criteria air contaminant emissions

Waste products destined for landfills with high calorific value are increasingly being explored for potential use in a variety of industries. One example is the potential use of these wastes in cement kilns to reduce greenhouse gas (GHG) emissions from cement production. This study develops a cradle-to-gate life cycle assessment (LCA) model to estimate the GHG emissions, criteria air contaminants (CAC), and the impact of biogenic carbon accounting methods in biomass-containing alternative fuels (AFs) on life cycle GHG emissions when replacing natural gas with AFs at a cement facility. The proposed AF mixture includes landfill wastes like construction and demolition waste, asphalt shingles, tire fluff, carpet, textiles, and plastics. While many LCAs assume the biogenic fraction's climate impact is carbon-neutral, its actual effects depend on a range of new methods being proposed to account for the climate impacts associated with biogenic carbon. The findings of this study demonstrate a reduction of approximately 7–13% in life cycle GHG emissions. The preliminary estimates suggest that the change to CACs will likely not be materially different from the current use of natural gas. It also emphasizes the importance of accounting for the biogenic fraction in biomass-based AFs, indicating a potential overall reduction of up to 7.2% in life cycle GHG emissions when the biogenic fraction is treated as carbon-neutral. While factoring in the benefits of shorter rotation and longer storage periods results in a 12.7% reduction in life cycle GHG emissions. The LCA model developed in this study holds the potential for broad application among cement facilities that are considering fossil to alternative fuels as part of their GHG emission reduction strategies.

Cement makers advance carbon capture

Two construction material firms have selected technology partners for facilities that will capture and use some of the carbon dioxide generated at their cement plants. In British Columbia, Lafarge is adding a CO 2 -to-chemical system from the start-up Dimensional Energy to carbon capture pilot equipment from Svante that has operated at Lafarge’s Richmond cement plant since January 2021 . Svante captures CO 2 with solid sorbents based on metal-organic frameworks. When completed, the system will pull 1 metric ton (t) of CO 2 per day from Lafarge’s cement facility and react it with hydrogen to yield roughly 180 L of hydrocarbon waxes. Lafarge says a local means of CO 2 utilization is critical for decarbonizing heavy industry in British Columbia because the province doesn’t have the transportation and sequestration infrastructure to dispose of the greenhouse gas underground. “Carbon capture is an important lever in our net-zero roadmap. However, for

A machine learning approach for clinker quality prediction and nonlinear model predictive control design for a rotary cement kiln

AbstractCement manufacturing is energy‐intensive (5Gj/t) and comprises a significant portion of the energy footprint of concrete systems. Incorporating modern monitoring, simulation and control systems will allow lower energy use, lower environmental impact, and lower costs of this widely used construction material. One of the goals of the CESMII roadmap project on the Smart Manufacturing of Cement included developing an analytical process model for clinker quality that includes the chemistry of the kiln feed and accounts for critical process variables. This predictive model will be used in nonlinear model predictive control system designed to significantly reduce process energy use while maintaining or improving product quality. In the cement manufacturing plant used in this study, the kiln feed (meal) is tested every 12 h and used to estimate the mineral composition of the cement kiln output (clinker) using the stoichiometry‐based Bogue's model and the expertise of the plant operators. During kiln operation, kiln output (clinker) is sampled and tested every 2 h to measure its chemical and mineral composition. The predicted and measured values of the clinker composition are used by the plant operators to adjust the kiln input stream and the production process characteristics to maintain stable operation and uniform product quality. However, the time delay between prediction and testing, along with inaccuracies inherent in the Bogue's model have made any process changes designed to minimize energy use problematic, especially in‐light of potential clinker quality issues that process changes often pose. A new analytical model that integrates quality information and process operation information has been developed from data collected from 2 years of production from an operating cement facility. To make the model fuel‐type‐independent, consumed heat energy was computed in the model instead of fuel type and amount. A Feedforward Network was trained and tailored from collected data. Many data‐based simulations were conducted to quantitatively evaluate the proposed model and the 5‐fold cross‐validation procedure was used to test the models. The resulting predictive model was shown to have a low root mean square error (MSE) with respect to the estimated clinker mineral composition compared to that using the industry standard “Bogue’ model”. The end goal of this work was to develop a single machine learning tool that allows the use of quality control data and process control variables to improve energy efficiency of the process in a continuous fashion. The proposed nonlinear model predictive control system (NMPC) can generate predicted kiln production characteristics based on manipulated variables in manner that accurately follows the target product quality values. Simulation results also show that the proposed model produced accurate predictions of kiln outputs that fell within the required constraints, while manipulating control variables within typical operational ranges.

FEED Study for Retrofitting Holcim U.S. Cement Facility with CO2 Capture Plant Using Air Liquide Adsorption Assisted Cryogenic Technology

FEED Study for Retrofitting Holcim U.S. Cement Facility with CO2 Capture Plant Using Air Liquide Adsorption Assisted Cryogenic Technology

Thermodynamic analysis of a new multi-generation plant based on the waste heat from the cement industry for improved energy management

In this paper, the hydrogen production and liquefaction option by utilising the waste heat from the raw material preheating sub-unit of cement facility are investigated thermodynamically. The gas turbine plant and Rankine cycle are chosen to generate power and, also in order to generate hydrogen, a part of the produced power is used for PEM electrolysis. In these conditions, the hydrogen generation from analysed integrated plant is computed as 0.028 kg/s. The energetic and exergetic effectiveness of Brayton and Rankine cycles integrated with the waste heat recovery process in the cement facility are computed as 58.24% and 42.17%, respectively, for the chosen working condition. It is also asserted that increasing the input temperature of gas turbine depended on the cyclone gas temperature, and increases the exergy efficiency of the investigated system.

Heavy Metal Pollution in Soil Samples Obtained from some Communities around a Cement Factory in Obajana, Kogi State, Nigeria

This study assessed the levels of heavy metals in the soils of three communities (Lokoja, Osara, and Kabba) within forty kilometers from a Cement factory situated in Obajana, Kogi State of Nigeria. Soil pH values ranged from 6.0 - 7.3, organic matter ranged from 2.5±0.5-4.03±0.3 %, Electrical Conductivity ranged from 104.1±31.5-188.5±75.5 µS/Cm, carbonates ranged from 2.8±0.8-3.7±0.5 mg/kg. The order of pollution of the locations under study was Lokoja > Osara > Kabba > Control based on the Pollution Load Index calculation. The elements’ dominance was in the order: Zn >Pb >Cu> Ni > Cd in general. Lokoja: Zn-31.32, Pb-30.78, Cu-28.12, Ni- 22.723, and Cd-1.63 mgkg-1 Osara: Cu-22.32, Zn-21.56, Pb-16.31, Ni- 3.61, and Cd-1.16 mgkg-1 Kabba: Zn-17.98, Cu-6.05, Pb-5.89, Ni- 4.70, and Cd-1.105 mgkg-1. Higher elemental concentrations were observed in Lokoja and Osara. The I-geo results indicated that the Cu and Ni were moderately to strongly polluted metals in Lokoja with I-geo 4.15 and 3.84 respectively, while Cu I-geo= 1.85), and Ni (I-geo=1.59) in Kabba and Cd (I-geo=1.93), Ni (I-geo=1.18) and Pb (I-geo=1.67) were moderately polluted. However Zn was, according to the I-geo values, unpolluted both in Kabba and Osara but moderately polluted in Lokoja. The PLI values ranged from 2.04 to 6.3 indicating that some of the studied metals exceeded the background (Control) metal concentration. The mathematical models revealed that the source of pollution was anthropogenic, the cement facility together with the attendant vehicular traffic and emissions were implicated as responsible for metal pollution in these areas.

HEAVY METALS PROFILE AND VARIATIONS OF SOIL PROPERTIES IN A VICINITY OF CEMENT FACTORY IN OBAJANA IN KOGI STATE OF NIGERIA

Purpose of study: Soils from the vicinity of a cement factory in Obajana in Kogi state of Nigeria were analyzed for their physicochemical and elemental contents in order to assess the contamination level of the soils.
 Methodology: Samples were collected at twenty-two identified transects of the soils near the cement factory using standard analytical procedures during Dry and Rainy seasons. The elemental contents of the soils were determined using the Atomic Absorption Spectroscopy (AAS) technique while the physicochemical parameters were determined using standard analytical techniques.
 Main Findings: Results indicated that the physicochemical parameter values varied across the study areas. Ten elements (As, Ca, Co, Cr, Cu, Fe, Mg, Ni, Pb and Zn) were analyzed and their concentrations values established. In addition, calculation of Enrichment Factors (EFs), Geo - accumulation Index (Igeo), Pollution Indices (PI) and Pearson correlation matrices were performed and the results indicated that across the transects some elements were in the highly pollution class and strongly correlated. 
 Implications: The cement facility together with the attendant vehicular traffic emissions were implicated as responsible for metal pollution in the area as higher concentration of metals were found in the sites closer to the cement factory.
 Originality/Novelty: Researchers did this study in their lab and this give can help government to set policies to safeguard health of community.

ENERGY, EXERGY AND EXERGOECONOMIC ASSESSMENT OF A DRY TYPE ROTARY KILN

This study deals with, energy, exergy, specific energy consumption (SEC) and exergoeconomic assessment of a burner (dry-type) in a currently running cement facility in Şanlıurfa, Turkey. The exergoeconomic analysis of the unit is evaluated. The first and second law analysis including exergy destructions and exergetic cost allotments are analyzed for the unit. The first and second law efficiencies and SEC of the kiln are calculated to be 54%, 29% and 3793 kJ/kg clinker respectively. The specific cost method (SPECO) has been used for the exergoeconomic analysis. The exergetic cost and cost rate and of the clinker product of the rotary kiln are found to be 77.3 $/GJ and 2608 $/h, respectively.

New landscapes of conflict: land-use competition at the urban–rural fringe

Land-use conflict research generally focuses on conflicts where pre-existing opponents respond to the introduction of a new unwanted land-use. We select a 2008 land-use conflict to explore an understudied scenario: urban–rural fringe (URF) expansion can introduce new opposing stakeholders into areas with pre-existing unwanted land-uses. We use spatial analysis methods to measure the rate and direction of URF expansion in relation to a vacated cement facility that had been approved for revitalisation in 2008, motivating a land-use conflict between competing stakeholders. Findings indicate that the cement facility and surrounding land-uses had been continuously used for similar noxious activities since 1964, but URF expansion changed the area’s surrounding landscape from rural-majority to urban-majority prior to the 2008 land-use conflict. The association between URF expansion and space-related drivers of land-use conflict is a necessary consideration when studying increasingly urbanised landscapes.

Energetic and exergetic performance investigation of a cement facility for clinker production

Energetic and exergetic performance investigation of a cement facility for clinker production

Energetic and exergetic performance investigation of a cement facility for clinker production

In this study, the energetic and exergetic analyses of a cement plant for clinker production are investigated. The exergy destruction rate, energy and exergy efficiency of process components are presented by using the thermodynamic balance equations. The energetic and exergetic efficiencies of cement plant are calculated as 60.78%, and 46.11%, respectively. The rotary kiln, raw mill and cooler component have the maximum exergy destruction rate among the other process components. The exergy efficiency of rotary kiln, raw mill and cooler component are calculated as 57.36%, 33.52% and 49.46%, respectively. Also, to analyse the cement plant performance more comprehensively, the parametric studies are conducted to determine the impacts of different design variables, such as rotary kiln temperature and raw material mass flow rate, and feedstock coal chemical properties and varying of ambient temperature on the energy efficiency, exergy efficiency and exergy destruction rate of plant components.

Environmental management of bottom ash from municipal solid waste incineration based on a life cycle assessment approach

Conventional bottom ash (BA) management consists of a solidification process using inorganic binder reagents, such as cement. However, despite the heavy metal content, the use of BA as a natural aggregate has become increasingly more common. In particular, bottom ash is used as a raw material for clinker, cement mortar or frit production, as a drainage layer in landfills or as a sub-base material in road construction. In this study, the life cycle assessment approach was used to evaluate and compare ash solidification with ash recycling in Portland cement production as a clinker and gypsum substitute. The findings showed that the substitution of ash for clinker resulted in the lowest natural resources (NR) consumption and the lowest environmental burdens (EB). The decrease in the clinker substitution percentage generated a higher NR consumption and an increased EB. In ash recycling, the distance between the incinerator and the cement facility is an important parameter in the decision-making process. Specifically, ash solidification presented less favourable results than ash recycling (with a clinker substitution of 25 %), despite the increasing distance between the incinerator and the cement facility. However, when the clinker substitution decreased to 2.5 % or when ash was substituted for gypsum, the distance played an important role in the water impact.

Recycling contaminated soil as alternative raw material in cement facilities: Life cycle assessment

Volcanic soil can be used to remove metals from wastewaters. Once used, it is disposed in landfills. The utilization of this material in the cement industry as an alternative raw material was evaluated using life cycle assessment (LCA) methodology. This possibility has been studied from an environmental point of view in a Chilean cement facility, representative of the current operation state of art, including both technical and economic analysis. Two scenarios were compared: Scenario 1, which corresponds to the existing cement production process, and Scenario 2, which represents cement production using spent volcanic soil. With the exception of the categories of carcinogens (C) and minerals (M), the comparative results are favourable to Scenario 2, specially regarding to the category of ecotoxicity (E), mainly due to the avoided landfilling emissions of the volcanic soil. When considering the damage assessment, damage to human health (HH), ecosystem quality (EQ) and resources (R) are lower in Scenario 2. In addition, sensitivity analyses were performed to study the influence of particular parameters (i.e., transport of spent volcanic soil, CO 2 emissions from the clinkerization process and heavy metals leaching from the spent volcanic soil) on the results of the assessment. The use of alternative raw materials (in this case, spent volcanic soil), which present the advantage to be wastes from other technical systems, appear to allow the development of cement production in a more sustainable way, slightly improving the economy of the process. The spent volcanic soil can be treated with zero cost for the wastewater treatment plant with savings of 0.23€ for each tonne of clinker production. Establishing a sound management way for the spent volcanic soil could foment its possible use as mineral adsorbent in industrial wastewater treatment facilities.

Ichthyofaunal survey of rivers within Ewekoro cement manufacturing operational areas

A total of 298 fish specimens belonging to seven families were caught during ichthyoplanktonic survey of three rivers within the Ewekoro cement facility catchment area located in southwestern Nigeria. The highest numbers of specimens were caught from Alaguntan (37.0%) and Elebute (36.6%) rivers while 28.9% of the fish samples were collected from Itori River. The fish population and species diversity recorded in the catchment rivers were significantly lower (p < 0.05) than comparative catches from Ewekoro River located about 30 km downstream of the factory operational area. The food items ingested by the specimens across the seasons in the catchment rivers revealed obvious differences in diet with some degree of overlap in the fish trophic preferences. However, the omnivorous species dominated the catches in each of the rivers, irrespective of season. Categorization of the fish specimens based on habitat-related adaptive physiology showed that a significant number of the fish from Alaguntan and Itori Rivers have accessory respiratory organs. The four species with accessory respiratory organs were Polypterus senegalus Curv., Clarias gariepinus C. & V., Ctenopoma kingslayae Gun. and Channa obscura Smith. Of the 12 fish species recorded in the Ewekoro cement facility catchment rivers, only P. senegalus, C. gariepinus, C. obscura and Oreochromis niloticus (Trew.) are valuable food fishes in southwestern Nigeria.

循環型産業システムの計画とその環境改善効果の算定―川崎エコタウンにおける循環型セメント事業のケーススタディ―

産業共生 (Industrial symbiosis) の理念および川崎エコタウンの調査に基づき, 循環型事業の計画手法を提案し, 環境改善効果を算定するための枠組みを提示した. 次に, 川崎エコタウンを対象とし, セメント工場を核とした循環型事業を計画し, そのLCCO2を算定した. その結果, 廃棄物を利用しないケース (ベースライン) と比較して, 現状での循環型事業では, 約3.6万t-CO2/yの削減効果があることが示された. また, 川崎市内から排出される産業廃棄物, さらに川崎市内から排出される産業廃棄物および一般廃棄物を利用した循環型事業では, それぞれ約3.8万t-CO2/y, 13.7万t-CO2/yの削減効果があることが示された.

Enhancing analytical methods of collective decision making

A common method of analysis when decisions have to be made by multiple stakeholders using multiple criteria is value tree analysis. Variations of this, such as the Public Value Forum (PVF), have been used especially in complex choices involving environmental issues [Keeney et al., MgtSci, 36, 9, 1990, pp. 1011-30]. Value tree analysis uses Multiattribute Utility Theory (MAUT) [Keeney and Raiffa, 1976] to evaluate a large number of alternatives. Decisionmakers decide the impact an alternative will have on each of many attributes and express how important each attribute is to them. The choice of attributes and the weights attached to them provide evidence of their values and preferences. The success of the PVF depends on the fact that individuals will understand each others' positions as they make explicit the tradeoffs among various attributes. However, participants in the PVF may have difficulty conveying in a precise way the information needed to calculate value scores and preference weights. Also, the language of MAUT lacks the flexibility to measure the degree to which a consensus of opinion can be reached. Fuzzy analysis [Zadeh, Info&Ctrl, 8, 1965, pp. 338-53] provides for uncertainty in scale responses which can be very common in a decisionmaker's choice of environment and flexibility of linguistic expression of preferences. The authors had a group of students decide whether to retain the present use of a cement facility or to adopt a modified use of the facility which involved the use of hazardous waste. Three stakeholder groups emerged from the student group--the community, the company, and the local officials. The attributes used by the participants were monetary impact, risk reduction, risk preference, health, and environmental quality. Using the fuzzy linguistic acceptability, the authors searched for the degree of acceptability each attribute had with each group and determined the lowest degree of acceptability around which a consensus could be obtained on an attribute, e.g., health. Also obtained for each attribute was a most desirable outcome, around which a consensus could be obtained. By examining the difference between the lowest consensus value and the most desirable outcome determined by a stakeholder group on a particular attribute, the authors identified where the greatest disagreement would arise. Thus, the outcome of the decision process is broadened from a single choice. Moreover, using joint analysis of the impact of each attribute and the most desirable outcome, one could assess that the most likely outcome of the decision process would be to reject the modified use of the facility. Strategic behavior could have been adopted by the students and there were limitations in the scope of study and the specifics of the scenario. However, the approach allows the inclusion of linguistic expressions difficult with the use of the traditional quantitative method of MAUT alone. One could expect to see that the complexity of a policy issue like this one is better handled, and its results better defended, with this inclusive, modified use of the PVF in which decisionmaking is enhanced by the use of fuzzy systems.