Su Ping Cui

CO2 Emissions due to Cement Manufacture

With increasing concerns about global warming, and the cement plants emitting huge CO2, it is necessary to know how the CO2 emits and how much the CO2 emits due to cement manufacture in both direct and indirect ways. A precise method to calculate CO2 emissions including three processes was established in this paper and a case study was provided. From the case of LQDX plant, we can see the amount of CO2 emissions at the right level. The summary of CO2 emissions is consisted by emissions from raw materials, fuels and electricity. The direct CO2 emissions are 0.822 ton CO2 per ton clinker, and the total CO2 emissions are 0.657 ton CO2 per ton cement in this study. Therefore, the way that CO2 emissions due to cement manufacture was pictured and then measured. An approach provides a basic framework to identify various situations in different cement plants in China and other in the rest of the world. The framework would be useful in quantitatively evaluating CO2 emissions for government to know precisely CO2 emissions in cement plants.

LCA Method of MSC and Low-NOx Burner Technology in Cement Manufacturing

LCA method was used to model the life cycle of cement manufacturing with multi-stage combustion and low-NOx Burner technology applied as its low-NOx system. The life cycle is from the coal and raw materials transportation, through the coal and raw meal grinding, to the clinker incineration, and finally the flue gas including NOx to the air atmosphere. The functional unit is 1 tonne clinker. Data for cement produced in MSC and LNB technology is analyzed. The data is collected from the real clinker production situation and the measurement is taken in 12 hours continuously.

Effect of Cerium on Manganese Base Catalysts by Co-Precipitation for Low-Temperature SCR of NO with NH3

Catalysts of Mn/TiO2 and Mn-Ce /TiO2 prepared by co-precipitation method for low temperature selective catalytic reduction (SCR) of NO with NH3 were investigated in this study. The experimental results showed that co-precipitation method after improvement, the NO conversion of Mn-Ce/TiO2 catalyst increased sharply. Meanwhile, the addition of cerium has significant effects on the catalytic activity. Characterizations of catalysts were carried out by XRD, BET and H2-TPR. The characterized results indicated that co-precipitation method after improvement, in temperature windows 150 to 300 °C, showed higher NOx conversion.

Analysis on the CO2 Emission of Calcium Carbide Sludge as Secondary Raw Material in Cement Clinker Production

With the development of economy, China has become one of the largest cement producers in the world. However, cement industry is a main contributor of global carbon emissions. Substituting calcium carbide sludge for limestone is an effective method for CO2 emission reduction in cement industry and has developed rapidly in recent years in China. The purpose of this study is to determine the life cycle CO2 emission of cement clinker produced with calcium carbide sludge as secondary raw material. The results show that compared with general cement clinker, the life cycle CO2 emission intensity of cement clinker produced with calcium carbide sludge will be decreased by 39.1% when substitution rate is 80%. And the CO2 emission results from the procedure of cement clinker production accounts for 85.7% of the total emission, in this stage, the CO2 emission declined by 42.2%.

Using Calcium Carbide Slag as One of Calcium-Containing Raw Materials to Produce Cement Clinker

Calcium carbide Slag is from CaC2 hydrolysis reaction and will do harm to land and make pollution. Calcium carbide slag can be a substitute for limestone to produce clinker with a high portion of CaO as an excellent calcium raw material. As a kind of industrial wastes, the properties of calcium carbide slag differentiate from that of natural limestone. In the present investigation, the modern analysis methods of XRF, XRD, DTA/TG, petrographic analysis were used to compare carbide slag and limestone, and the results showed that the main chemical compositions of the calcium carbide slag were basically the same with that of natural limestone. Comparing with limestone materials, calcium carbide slag had a higher content of CaO, and the main mineral phase constituent of limestone was CaCO3, whereas the main mineral of calcium carbide slag was Ca (OH)2 with a lower decomposition temperature. It has been found that under the same temperature the amount of C3S in the clinker of calcium carbide slag batching was slightly less than that of limestone batching.

Recycled CRT Funnel Glass as Coarse Aggregate and Fine Aggregate in the Radiation Protection Concrete

In recent decades, high-tech electrical equipment has drastically proliferated instead of Cathode Ray Tube (CRT), making CRT funnel glass potential hazardous solid waste. Due to a relatively high level of lead, CRT funnel glass could be used as a potential material for the production of anti-radioactive concrete. In our study the CRT funnel glass , which was separated as aggregate in the concrete, was reduced to 4.75-25 mm (coarse aggregates) and less 4.75 mm (fine aggregates) in the production of anti-radioactive concrete. Mixes containing 0%, 20%, 40% , 60%, 80% and 100% (volume percentage) of CRT funnel glass to replace fine aggregate and coarse aggregate (respectively or simultaneously)) were prepared. The influence of the size, shape and replacement percentage of aggregates on workability, compressive strength and radiation shielding performance were determined. It was found that the replacement of natural aggregate with recycled CRT glass considerably improved the slump and radiation shielding performance but reduced compressive strength. The optimum percentage of waste funnel glass used as fine aggregate and coarse aggregate was 40%. The results clearly showed that the CRT funnel glass performed a significant enhancement in radiation shielding properties.

Life Cycle Assessment of Heavy-Duty Truck for Highway Transport in China

The detailed life cycle assessment of heavy-duty truck for highway transport in China is conducted by Centre of National Material Life Cycle Assessment (CNMLCA). The input of energy and output of pollutants emissions are documented as the life cycle inventory (LCI). The life cycle impact assessment (LCIA) results calculated with the CML method show that the hotspot of environmental impacts from transport in China. The environmental benefits from implementations of European emissions standards in China for transport are also analyzed. The analysis shows that the acidification potential (AP) makes the most huge contribution to total environmental impact, up to 33.7%. As the second hotsopt, global warming potential (GWP) takes up 26.83% of total environmental impact. Photochemical oxidant formation potential (POCP) takes up 23.42% of total environmental impact, which is more or less the same comparing with the result of GWP. Eutrophication potential (EP) takes up 15.05% of total environmental impact. The last but not the least environmental impact category - human toxicity potential (HTP), only takes up 0.95% of total environmental impact. If the heavy metal and dioxin emissions are also considered, maybe the results will be changed and the HTP will take more in the whole environmental impact. It can be concluded that if we pay more attention on SO2 emissions especially NOx emissions reduction, the acidification and photochemical smog would be relieved a lot and the total environmental impact can be decreased a lot. More punishment on overload may be a good choice to reduce environmental load of heavy truck of highway transport in China.

LCI Study of SCR DeNOx Technology for Cement Industry

LCI study is short for life cycle inventory study. In the situation of more strict regulation limit of 500 mg NOx /m3 a demonstration project to reduce NOx emissions with clinker production capacity of 2000 t/d in Beijing is supported by the Five-twelfth National Science and Technology Support Program of China Science and Technology Department. A selective catalytic reduction denitration (SCR DeNOx) technology is expected to be applied in this project. LCA models the life cycle of cement manufacturing with SCR DeNOx technology applied as its SCR system. The life cycle is from the coal and raw materials transportation, through the coal and raw meal grinding, to the clinker incineration, and finally the flue gas including NOx to the SCR reactor. The functional unit is 1 ton clinker. Data for cement produced in LNB technology as bench mark is analyzed and the SCR scenarios are to show that the SCR reactor can be established because the additional environmental impact is small due to small consumptions of reducing agent and electricity. SCR technology enable the deNOx efficiency much higher with small environmental impact.

CO 2 Emission Analysis of Light Aggregate Concrete Block in China

The development and application of light aggregate concrete blocks are considered as one of the key issue that promote the energy saving and emission reduction in construction and building materials industries. In this paper, the greenhouse gas (GHG) emissions of light aggregate concrete blocks during the whole life cycle were analyzed based on life cycle assessment (LCA) methodology. The results demonstrated that the amount of GHG emissions of the light aggregate concrete block was 174 kg/m3 in the system boundary of ‘from cradle to gate’. The direct GHG emissions was 51.31 kg/m3 accounting for 28.46% of the aggregate emission, while the indirect GHG emissions was 124 kg/m3. The cement production and the concrete block production were the main contributors to the total emissions. According to the sensitivity analysis, the GHG emissions amount was quite sensitive to the amount of cement and ceramsite consumption.

Effect of CaO on SNCR Reaction with NH3 as Reducing Agent

Selective non-catalytic reduction (SNCR) is a denitration method in the high temperature area, and NH3 or urea is used for SNCR as reducing agents to react with NOX to produce N2 in the flue gas in the temperature ranged from 850°C to 1100°C. The SNCR deNOx technology has been well used in utility boiler, but compared with it, the lower denitration efficiency and the larger consumption of ammonia indicate a more complex process in cement pre-calciner. Unlike in utility boiler, the presence of high concentrations of cement raw materials may influence SNCR denitration reaction process in cement kilns. Therefore, studying the effect of CaO which occupy the major composition of cement raw material is very important in SNCR process. In this study the influence of CaO on the SNCR deNOx process was investigated by simulating SNCR reaction at temperature that ranges from 750°C to 1100°C with different normalized stoichiometric ratio. The experimental results demonstrate that the addition of CaO increases the optimum denitration temperature to 1100°C, but it has no effect on normalized stoichiometric ratio. In the whole reaction process NH3 not only restores NO to O2 but also reacts with O2 to NO. Since the adsorption of NH3 on CaO surface, in the temperature range of 750°C-850°C the addition of CaO promotes the reaction of NH3 and O2 and increases NOX concentration. However, in the temperature range of 850°C-1000°C it not only promotes NH3 oxidation but also inhibits the reduction reaction of NH3, thereby the denitration reaction is inhibited. In the temperature range of 1050°C-1100°C the denitration reaction is promoted due to the NH3 desorption from CaO surface.