Partial replacement of fossil fuel in a cement plant: Risk assessment for the population living in the neighborhood

In cement plants, the substitution of traditional fossil fuels not only allows a reduction of CO₂, but it also means to check-out residual materials, such as sewage sludge or municipal solid wastes (MSW), which should otherwise be disposed somehow/somewhere. In recent months, a cement plant placed in Alcanar (Catalonia, Spain) has been conducting tests to replace fossil fuel by refuse-derived fuel (RDF) from MSW. In July 2009, an operational test was progressively initiated by reaching a maximum of partial substitution of 20% of the required energy. In order to study the influence of the new process, environmental monitoring surveys were performed before and after the RDF implementation. Metals and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in soil, herbage, and air samples collected around the facility. In soils, significant decreases of PCDD/F levels, as well as in some metal concentrations were found, while no significant increases in the concentrations of these pollutants were observed. In turn, PM₁₀ levels remained constant, with a value of 16 μg m^− 3. In both surveys, the carcinogenic and non-carcinogenic risks derived from exposure to metals and PCDD/Fs for the population living in the vicinity of the facility were within the ranges considered as acceptable according to national and international standards. This means that RDF may be a successful choice in front of classical fossil fuels, being in accordance with the new EU environmental policies, which entail the reduction of CO₂ emissions and the energetic valorization of MSW. However, further long-term environmental studies are necessary to corroborate the harmlessness of RDF, in terms of human health risks.     

Use of Cement Kilns in Managing Solid and Hazardous Wastes: Implementation in Australia

The use of cement kilns for managing solid and hazardous wastes is facilitated by the high temperature, long gas retention periods, natural alkaline environment, minimum amount of waste produced and high thermal capacity. The main benefits include energy recovery, conservation of fossil fuels, reduction in cement production costs and the use of already existing facilities.
The test burns conducted in cement kilns worldwide have demonstrated very high destruction efficiencies for most stable organic compounds, with toxic contaminants barely above the background levels.
There are several cement plants in the US and Europe presently using solid and hazardous wastes as supplementary fuel. The application of this technology in Australia has been ignored in the past. An international conference (Kilnburn'92) on the role of cement kilns in waste management was held recently in Australia and has enhanced the implementation of this technology in Australia.     

Indoor air pollution and its impact on children under five years old in Bangladesh

Indoor air concentrations of volatile organic compounds (VOCs), carbon monoxide (CO), carbon dioxide (CO2), nitrogen dioxide (NO2), and dust particles were measured for 49 biomass and 46 fossil fuel users in urban slums of Dhaka, Bangladesh. The health impacts of these pollutants were assessed on 65 and 51 children under five years old from families who use biomass and fossil fuel as main source of energy, respectively. Mean concentrations of CO were found to be significantly higher in biomass fuel users (P = 0.010), while geometric mean concentrations of benzene, xylene, toluene, hexane, total VOCs, and NO2 were significantly higher (P < 0.01) in the fossil fuel users. Symptoms such as redness of eyes, itching of skin, nasal discharge, cough, shortness of breath, chest tightness, wheezing, or whistling chest were found to be associated with the choice of biomass fuel, with the odds ratio ranging from 4.0 to 6.3. No significant association of use of biomass fuel with respiratory diseases, eczema, diarrhea, or viral fever was observed after adjustment for potential confounders. These results suggest a significant association between the biomass fuel-using population and respiratory symptoms. These symptoms may not be due to the pollutants only, as some other underlying causes may be present. PRACTICAL IMPLICATIONS: The health of children under five years old in Bangladesh, especially those living in poor socioeconomic conditions, is considered to be worsening because of indoor air pollution. It is commonly suggested that biomass fuel should be replaced by fossil fuel, as pollution levels are believed to be higher with biomass fuel. Our findings, however, suggest that pollution can be higher with fossil fuels, and indicate that a switch in fuel from biomass to fossil does not necessarily improve the children's health. Awareness programs should therefore be undertaken to avoid the unnecessary use of gas. Clean fuels and clean stoves should also be ensured to reduce emissions of indoor air pollutants.     

Effect on exhaust emissions by the use of methylcyclopentadienyl manganese tricarbonyl (MMT) fuel additive and other lead replacement gasolines

This paper examines the potential effects on car exhaust emissions of a range of alternative lead replacement gasolines in the context of south European countries such as Greece. The main objective of this study was to assess the effects on emissions from non-catalyst passenger vehicles by the substitution of leaded ('super') gasoline with Euro95 unleaded enriched with the additive MMT or other alternative to leaded gasoline fuels. Regulated emissions, two non-regulated pollutants and vehicle performance were measured on two catalyst-equipped and two conventional, non-catalyst vehicles. It was found that there was no measurable effect on regulated emissions (CO, HC and NO(x)) and on fuel consumption by the introduction of the lead replacement fuels for both catalyst and non-catalyst cars. In the case of the non-catalyst car, the shift from leaded to unleaded gasoline was associated with an increase in benzene and formaldehyde emissions, a trend probably attributable to the increased aromatics content of the lead replacement fuels.     

An X-ray diffraction (XRD) and Fourier transform infrared spectroscopic (FT-IR) investigation of the long-term effect on the solidification/stabilization (S/S) of arsenic(V) in Portland cement type-V

The long-term effects on solidification/stabilization (S/S) of As5+-bearing oxyanions (AsO4(3)-) in Portland cement type-V (OPC) have been investigated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopic (FT-IR) techniques. The results of this study confirm our previous results that the early hydration of cement is inhibited by the presence of AsO4(3)-, and that the inhibition is mainly caused by the formation of highly insoluble Ca3(AsO4)2 on the surface of hydrating cement particles. Arsenate analog of ettringite [Ca6(Al2O6)(SO4)3 x 32H2O] was identified in the early stages of hydration of pure Portland cement and As(V)-treated Portland cement [OPC-As(V)], but not in 10-year-old similar samples. The XRD and FT-IR results indicated interactions of oxyanions and cement particles to produce minor quantities of As5+-bearing compounds in fresh as well as in 10-year-old samples. New As5+-bearing phases, NaCaAsO4 x 7.5H2O and Ca5(AsO4)3OH were identified in the 10-year-old OPC-As(V) samples by XRD analyses. Based on these results it is concluded that Portland cement may be considered as a potential matrix to immobilize As5+-bearing wastes.     

Mercury regulation, fate, transport, transformation, and abatement within cement manufacturing facilities: review

The USEPA's 2010 mercury rule, which would reduce emissions from non-hazardous waste burning cement manufacturing facilities by an estimated 94%, represents a substantial regulatory challenge for the industry. These regulations, based on the performance of facilities that benefit from low concentrations of mercury in their feedstock and fuel inputs (e.g., limestone concentration was less than 25 ppb at each facility), will require non-compliant facilities to develop innovative controls. Control development is difficult because each facility's emissions must be assessed and simple correlation to mercury concentrations in limestone or an assumption of ‘typically observed’ mercury concentrations in inputs are unsupported by available data. Furthermore, atmospheric emissions are highly variable due to an internal control mechanism that captures and loops mercury between the high-temperature kiln and low-temperature raw materials mill. Two models have been reported to predict emissions; however, they have not been benchmarked against data from the internal components that capture mercury and do not distinguish between mercury species, which have different sorption and desorption properties. Control strategies include technologies applied from other industries and technologies developed specifically for cement facilities. Reported technologies, listed from highest to lowest anticipated mercury removal, include purge of collected dust or raw meal, changes in feedstocks and fuels, wet scrubbing, cleaning of mercury enriched dust, dry sorbent injection, and dry and semi-dry scrubbing. The effectiveness of these technologies is limited by an inadequate understanding of sorption, desorption, and mercury species involved in internal loop mercury control. To comply with the mercury rule and to improve current mercury control technologies and practices, research is needed to advance fundamental knowledge regarding mercury species sorption and desorption dynamics on materials within cement facilities.     

Effects of portland composite and composite cements on durability of mortar and permeability of concrete

In this study, the effects of Portland composite and composite cement on the properties of cement paste, durability of mortar and permeability of concrete were investigated. The results were compared with reference mixture of cement paste, mortar and concrete made with Portland cement. The ratio of water to cementitious materials (W/C_m) in cement paste, mortar and concrete mixtures were determined in a way that all the similar mixtures had the same workability. Flexural tensile and compressive strength of mortar samples containing Portland Composite and Composite cement were determined at various ages. In cement paste samples, the shortest and longest setting time was obtained in samples made with Portland and composite cement, respectively. Also, maximum amount of volume expansion was found in the sample made with Portland composite cement. Mortar samples made with Portland composite and composite cement had lower strength values than the reference mortar mixture at early ages but at 28 days and later ages they had higher strength values than the reference mixture. In durability tests, there was no loss of weight and cracks in mortar mixture samples made with Portland composite and composite cement when they were held in microthiol, Na₂SO₄ and MgSO₄ solutions. Also, no water leakage was observed through the concrete samples made with Portland composite and composite cement when they were held under five-bar pressurized water.     

硅酸盐与磷铝酸盐复合水泥水化动力学的研究

研究了石膏掺量为3.5%(以SO3计,质量分数,下同)、磷铝酸盐水泥熟料掺量为10%的硅酸盐与磷铝酸盐复合水泥的力学性能和水化动力学,测定了该复合水泥在不同水化时间下的Ca2 和[SiO4]4-溶出浓度、相应的电导率及pH值.研究结果表明,磷铝酸盐水泥的掺入不仅可以提高硅酸盐水泥的水化硬化速率,而且能使硅酸盐水泥的早期以及后期强度有不同程度的提高.该复合水泥水化硬化浆体的Ca2 和[SiO4]4-的相对溶出浓度、电导率及pH值均较同龄期的硅酸盐水泥低,说明该复合水泥的水化产物较为稳定,不易溶解,而且碱性较低.硅酸盐与磷铝酸盐复合水泥的水化历程与硅酸盐水泥相同,经历5个阶段,即初始期或预诱导期、诱导期、加速反应期、减速反应期和稳定期.加速反应期的水化主要由成核反应控制,而稳定期的水化主要由扩散过程控制.     

Laboratory evaluation of incorporating waste ceramic materials into Portland cement and asphaltic concrete

Laboratory tests were conducted to evaluate the feasibility of incorporating fired ware scrap, a waste ceramic material from automobile manufacturing, into pavement material. In this study, crushed fired ware scraps were added into Portland cement concrete (PCC) and hot-mix asphalt (HMA) to replace fine aggregates.The results of this study indicated that the fired ware scraps can be potentially used in the Portland cement concrete and HMA mixture. The compressive strength of PCC was improved by adding crushed scrap. However, due to the high water absorption of the crushed scrap, crushed scrap content is recommended to be less than 10% and a water reduction additive is recommended to provide adequate workability. For HMA, the test results indicated that adding a certain amount (up to 15% by weight) of ground scrap improved the binder’s total resistance to deformation. The dynamic modulus, flow number and indirect tensile strength of the HMA mixture were all improved by adding “filler” made of ground scrap. 2.5% “filler” content was recommended for a dense-graded HMA surface mixture.     

Strength and water permeability of concrete containing palm oil fuel ash and rice husk–bark ash

In this paper, palm oil fuel ash and rice husk–bark ash, which are by-products from electricity generating power plants and disposed as wastes in landfills, were used as a partial cement replacement. They were ground and incorporated into concrete at the levels of 20%, 40% and 55% by weight of binder. Compressive strength and water permeability of concretes containing ground palm oil fuel ash (GPOA) and ground rice husk–bark ash (GRBA) were investigated. From the tests, the replacement of Portland cement by both materials resulted in the higher water demand in concrete mixtures as compared to ordinary Portland cement (OPC) concrete with compatible workability. The compressive strengths of concretes containing 20% of GPOA and GRBA were as high as that of OPC concrete and were reduced as the increase in the replacement ratios. Although the compressive strengths of concrete with the replacement of GPOA or GRBA up to 40% were lower than OPC concrete, their water permeabilities were still lower than that of OPC concrete. These results indicate that both of GPOA and GRBA can be applied as new pozzolanic materials to concrete with an acceptable strength as well as permeability.     

Experimental investigation of engine emissions with marine gas oil-oxygenate blends

This paper investigates the diesel engine performance and exhaust emissions with marine gas oil-alternative fuel additive. Marine gas oil (MGO) was selected as base fuel for the engine experiments. An oxygenate, diethylene glycol dimethyl ether (DGM), and a biodiesel (BD) jatropha oil methyl ester (JOME) with a volume of 10% were blended with the MGO fuel. JOME was derived from inedible jatropha oil. Lower emissions with diesel-BD blends (soybean methyl ester, rapeseed methyl ester etc.) have been established so far, but the effect of MGO-BD (JOME) blends on engine performance and emissions has been a growing interest as JOME (BD) is derived from inedible oil and MGO is frequently used in maritime transports. No phase separation between MGO-DGM and MGO-JOME blends was found. The neat MGO, MGO-DGM and MGO-JOME blends are termed as MGO, Ox10 and B10 respectively. The experiments were conducted with a six-cylinder, four-stroke, turbocharged, direct-injection Scania DC 1102 (DI) diesel engine. The experimental results showed significant reductions in fine particle number and mass emissions, PM and smoke emissions with Ox10 and B10 fuels compared to the MGO fuel. Other emissions including total unburned hydrocarbon (THC), carbon monoxide (CO) and engine noise were also reduced with the Ox10 and B10 fuels, while maintaining similar brake specific fuel consumption (BSFC) and thermal efficiency with MGO fuel. Oxides of nitrogen (NOx) emissions, on the other hand, were slightly higher with the Ox10 and B10 fuels at high engine load conditions.     

Radon emanation from concrete and the influence of using flyash in cement

In the Netherlands both Portland cement and blast furnace cement (slags from blast furnaces with about 30% Portland cement) are used for concrete.Radon exhalation measurements were carried out on concrete blocks made with these two types of cement and blocks with 15, 25 and 35% of the cement substituted by three different types of flyash.The results show that substituting part of the cement by flyash has no drastic effect on the exhalation rate. For concrete with Portland cement the exhalation rate decreases using flyash with an average radium content. With blast furanace cement a slight increase may be expected. The exhalation of concrete is greater than the sum of the exhalation values of the constituting components. The water in the pores the concrete plays an essential role in the emanation processs.     

Energy consumption and exhaust emissions in mechanized timber harvesting operations in Sweden

The study presents an estimation of the energy input and the amount of emissions to air due to fuel, chainsaw and hydraulic oil consumption by heavy duty diesel engine vehicles operating in forest logging operations in Sweden. Exhaust concentrations are given for carbon dioxide, carbon monoxide, nitrogen oxides, hydrocarbons and particulate matter. Three fuel types (rapeseed methyl ester, environmental class 1 and environmental class 3 diesel fuels) and two types of lubricating base oil (mineral- and vegetable-based) were examined. Energy input per unit of timber production (m3ub) was 82 MJ, 11% of which was due to energy consumption during the production phase of the fuel. Emissions during the whole life cycle of the fuels and the base oils are included in the study. The highest CO2 and NOx emissions occurred when rapeseed methyl ester was used as fuel together with rapeseed as base oil for chainsaw and hydraulic oil. The highest HC and CO emissions occurred when environmental class 3 diesel fuel was used.     

A combined approach to the evaluation of organic air pollution - a case study of urban air in Sarajevo and Tuzla(Bosnia and Herzegovina)

Organic pollution is a complex mixture where besides usually discussed polycyclic aromatic hydrocarbons (PAHs) a lot of other toxic or potentially toxic compounds occur. In this case, the organic air pollution in two important industrial cities, Sarajevo and Tuzla, in Bosnia and Herzegovina (part of former Yugoslavia) was assessed with the emphasis placed on genotoxic risks using both chemical (PAHs analyses) and biological approaches (genotoxicity testing with a screening bacterial genotoxicity test - SOS chromotest). The study was performed as a part of the APOPSBAL project (ICA2-CT2002-10007). So far there has not been any information either about the PAHs pollution or the genotoxic activity of the organic air pollution for the localities under the study. Therefore, the presented information is considered absolutely unique. Both used approaches made possible to identify the localities with the highest pollution level and genotoxic risks in both cities. Generally, higher levels of both parameters were determined in Tuzla, which is much more industrialized than Sarajevo, and especially at localities close to city centers and affected by traffic emissions, but also at localities polluted by emissions from industry and household heating. Even if benzo(a)pyrene concentrations exceeded the maximum permitted levels for this pollutant at some localities in Tuzla, the PAHs concentrations were fully comparable with the levels determined in other industrial European cities. Significant genotoxicity of the organic extracts was detected for almost all of the urban localities in the test both without (-S9; direct genotoxicity) and with the addition of metabolic activation (+S9; indirect genotoxicity). The observed direct genotoxic activities were discussed in relation to a potential presence of PAHs derivatives in the air. The indirect genotoxic activities were apparently higher at the localities with higher contents of carcinogenic PAHs. The significant relationship between the determined genotoxic activities and the PAHs pollution was also confirmed by a regression analysis. However, the correlations were not absolute because the observed genotoxic activity was also dependent on the presence of other organic pollutants than the PAHs. It concerns predominantly direct genotoxicity which is not related with the PAHs, but with their nitro-, oxi-, and hydroxy-derivatives and also other unknown polar organic pollutants. However, the concentrations of the direct genotoxins apparently correlated with the PAHs contents in the air. The study showed that screening genotoxicity tests, such as the SOS chromotest, could be effectively used for the identification of localities with increased genotoxic risks. In comparison with the health risk assessment which is usually based on the chemical analyses of only a small part of the pollution mixture, the bioassays enable us to evaluate the risks of all the mixture. The localities with the highest detected human health risks according to the screening bioassays may then be analyzed in detail with specific chemical methods to identify their causes.     

Vertical distributions of SO(2) and NO(2) in the lower atmosphere in Beijing urban areas, China

Measurements of SO(2) and NO(2) were conducted from January to March 2001 and August 2003 at a 325 m meteorological tower in Beijing. The concentrations of SO(2) and NO(2) observed by passive samplers at ten heights showed complex vertical distributions in winter and summer. The vertical profiles of pollutants were influenced by source emissions, meteorological conditions, urban canopy and other factors. The comparison analysis of winter and summer pollutant concentrations suggests that the decrease in SO(2) concentration was significant in summer, and the reduction of NO(2) was relatively not distinctive. Domestic heating and industrial sources were major sources of SO(2) in urban areas of Beijing. Differing from SO(2,) urban NO(2) was closely related to traffic emission. Meteorological evidence suggests that strong temperature inversions influence vertical distribution of air pollutants over urban Beijing. The high levels of SO(2) and NO(2) concentrations were due to the accumulation of pollutants resulting from the stable atmosphere prevalent during the measurement period. The vertical distributions of air pollutants were controlled and affected by atmospheric dynamical characteristics.     

Performance and emissions analysis of a diesel engine directly fuelled with waste cooking oil biodiesel

This research focuses on a comparative study of the physical and chemical properties of waste cooking oil (WCO) biodiesel with China stage IV diesel fuel. The estimate method of excess air ratio and the heating value ratio of an engine's cylinder mixture are proposed based on the differences of properties of two fuels. The bench tests of engine performance are carried out with an engine fuelled with two fuels separately. The estimated excess air ratio and the heating value ratio of an engine's cylinder mixture through the method are approximate to the experiment results. This comparison demonstrates that the estimate method can be applied to the performance analysis of an engine. Compared with China stage IV diesel, when a diesel engine is fuelled with WCO biodiesel, the torque and power decline from 1.9% to 13.8%; the brake-speci?c fuel consumption rises from 3.7% to 15.6%; CO, HC and PM emissions decrease significantly and NO_X emissions increase slightly.     

一种新型低碳水泥熟料技术

由于逐渐增多的环境法规限制,世界水泥生产商正在力争用低碳替代胶凝材料取代更多的硅酸盐水泥,以期减少水泥生产过程产生的碳足迹。矿渣、粉煤灰、石灰石等是主要使用的替代成分,但由于这些材料的供应量有限并需要满足性能标准要求,使这些替代材料的使用受到了限制。海德堡水泥公司开发的新型替代胶凝材料BCT技术,提供了进一步减少CO2排放的潜力。     

Fire safety tests comparing synthetic jet and diesel fuels with JP-8

Experimental fire tests have been performed on various fuels derived both from a petroleum source and from a synthetic source via a Fischer-Tropsch process. Multiple fire tests were performed for each fuel type as well as fuel blends of conventional and synthetic fuels using aqueous film-forming foam on a liquid pool fire following a prescribed military specification, MIL-F-24385F. Using the current U.S. Air Force jet fuel (JP-8) as a baseline comparison, the synthetic fuels or blends showed no significant difference in extinguishment times. Burnback times showed larger values for some of the synthetic fuels or blends when compared to JP-8, indicating improved safety for these synthetic fuels or blends.     

Variations in vanadium, nickel and lanthanoid element concentrations in urban air

The emission of trace metal pollutants by industry and transport takes place on a scale large enough to alter atmospheric chemistry and results in measurable differences between the urban background of inhalable particulate matter (PM) in different towns. This is particularly well demonstrated by the technogenic release into the atmosphere of V, Ni, and lanthanoid elements. We compare PM concentrations of these metals in large datasets from five industrial towns in Spain variously influenced by emissions from refinery, power station, shipping, stainless steel, ceramic tiles and brick-making. Increased La/Ce values in urban background inhalable PM, due to La-contamination from refineries and their residual products (fuel oils and petcoke), contrast with Ce-rich emissions from the ceramic related industry, and clearly demonstrate the value of this ratio as a sensitive and reliable tracer for many point source emissions. Similarly, anomalously high V/Ni values (> 4) can detect the influence of nearby high-V petcoke and fuel oil combustion, although the use of this ratio in urban background PM is limited by overlapping values in natural and anthropogenic materials. Geochemical characterisation of urban background PM is a valuable compliment to the physical monitoring of aerosols widely employed in urban areas, especially given the relevance of trace metal inhalation to urban health issues.     

Experimental investigation on regulated and unregulated emissions of a diesel engine fueled with ultra-low sulfur diesel fuel blended with biodiesel from waste cooking oil

Experiments were conducted on a 4-cylinder direct-injection diesel engine using ultra-low sulfur diesel, bi oesel and their blends, to investigate the regulated and unregulated emissions of the engine under five engine loads at an engine speed of 1800 rev/min. Blended fuels containing 19.6%, 39.4%, 59.4% and 79.6% by volume of biodiesel, corresponding to 2%, 4%, 6% and 8% by mass of oxygen in the blended fuel, were used. Biodiesel used in this study was converted from waste cooking oil.The following results are obtained with an increase of biodiesel in the fuel. The brake specific fuel consumption and the brake thermal efficiency increase. The HC and CO emissions decrease while NO_x and NO₂ emissions increase. The smoke opacity and particulate mass concentrations reduce significantly at high engine load. In addition, for submicron particles, the geometry mean diameter of the particles becomes smaller while the total number concentration increases. For the unregulated gaseous emissions, generally, the emissions of formaldehyde, 1,3-butadiene, toluene, xylene decrease, however, acetaldehyde and benzene emissions increase.The results indicate that the combination of ultra-low sulfur diesel and biodiesel from waste cooking oil gives similar results to those in the literature using higher sulfur diesel fuels and biodiesel from other sources.