Showing papers on "Co-processing published in 2010"

LCA allocation procedure used as an incitative method for waste recycling: An application to mineral additions in concrete

Abstract: Waste recycling avoids waste landfilling and all associated releases. It also allows for saving nonrenewable resources. However, the new commercial interest for waste can be seen as a shift in their status from waste to co-product. This has important consequences for environmental load allocation between the different industrial products (and co-products) in industrial plants. In this paper, the specific case of cement has been studied. Actually, to reduce the environmental impact of cement and concrete, industries have been engaged over the last 10 years to increase the replacement of Portland cement by alternative cementitious materials that are principally industrial waste or by-products. In this study, the environmental impacts of two different Supplementary Cementitious Materials (SCM), blast furnace slag and fly ash, are considered using Life Cycle Assessment methodology through a study of the influence of different allocation procedures on environmental impacts of SCM in concrete. Three allocation procedures are tested. In the first one, which is the current practice, no allocations are done. As for the two others, the environmental burdens of the system are respectively associated with the relative mass and some current economic values of the co-products and products. The results are discussed according to the specificity of the cement substitution products (SCM) and the driving forces that are identified for the use of these co-products. Then, a description investigation of another allocation procedure is proposed based on the fact that it is not the relative economic value that permits to evaluate the environmental burdens but the contrary. This last allocation procedure could be generalised for other waste recycling and be used as a regulation tool between the different industrial branches.

Generation, capture, and utilization of industrial carbon dioxide

Abstract: As a carbon-based life form living in a predominantly carbon-based environment, it is not surprising that we have created a carbon-based consumer society. Our principle sources of energy are carbon-based (coal, oil, and gas) and many of our consumer goods are derived from organic (i.e., carbon-based) chemicals (including plastics, fabrics and materials, personal care and cleaning products, dyes, and coatings). Even our large-volume inorganic-chemicals-based industries, including fertilizers and construction materials, rely on the consumption of carbon, notably in the form of large amounts of energy. The environmental problems which we now face and of which we are becoming increasingly aware result from a human-induced disturbance in the natural carbon cycle of the Earth caused by transferring large quantities of terrestrial carbon (coal, oil, and gas) to the atmosphere, mostly in the form of carbon dioxide. Carbon is by no means the only element whose natural cycle we have disturbed: we are transferring significant quantities of elements including phosphorus, sulfur, copper, and platinum from natural sinks or ores built up over millions of years to unnatural fates in the form of what we refer to as waste or pollution. However, our complete dependence on the carbon cycle means that its disturbance deserves special attention, as is now manifest in indicators such as climate change and escalating public concern over global warming. As with all disturbances in materials balances, we can seek to alleviate the problem by (1) dematerialization: a reduction in consumption; (2) rematerialization: a change in what we consume; or (3) transmaterialization: changing our attitude towards resources and waste. The "low-carbon" mantra that is popularly cited by organizations ranging from nongovernmental organizations to multinational companies and from local authorities to national governments is based on a combination of (1) and (2) (reducing carbon consumption though greater efficiency and lower per capita consumption, and replacing fossil energy sources with sources such as wind, wave, and solar, respectively). "Low carbon" is of inherently less value to the chemical and plastics industries at least in terms of raw materials although a version of (2), the use of biomass, does apply, especially if we use carbon sources that are renewable on a human timescale. There is however, another renewable, natural source of carbon that is widely available and for which greater utilization would help restore material balance and the natural cycle for carbon in terms of resource and waste. CO(2), perhaps the most widely discussed and feared chemical in modern society, is as fundamental to our survival as water, and like water we need to better understand the human as well as natural production and consumption of CO(2) so that we can attempt to get these into a sustainable balance. Current utilization of this valuable resource by the chemical industry is only 90 megatonne per year, compared to the 26.3 gigatonne CO(2) generated annually by combustion of fossil fuels for energy generation, as such significant opportunities exist for increased utilization of CO(2) generated from industrial processes. It is also essential that renewable energy is used if CO(2) is to be utilized as a C1 building block.

Decentralized Energy from Waste Systems

Abstract: In the last five years or so, biofuels have been given notable consideration worldwide as an alternative to fossil fuels, due to their potential to reduce greenhouse gas emissions by partial replacement of oil as a transport fuel. The production of biofuels using a sustainable approach, should consider local production of biofuels, obtained from local feedstocks and adapted to the socio-economical and environmental characteristics of the particular region where they are developed. Thus, decentralized energy from waste systems will exploit local biomass to optimize their production and consumption. Waste streams such as agricultural and wood residues, municipal solid waste, vegetable oils, and algae residues can all be integrated in energy from waste systems. An integral optimization of decentralized energy from waste systems should not be based on the optimization of each single process, but the overall optimization of the whole process. This is by obtaining optimal energy and environmental benefits, as well as collateral beneficial co-products such as soil fertilizers which will result in a higher food crop production and carbon dioxide fixation which will abate climate change.

A Study on the Reduction of CO2 Emission by the Application of Clean Technology in the Cement Industry

Abstract: : The feasibility of clean technology to minimize the CO 2 emission by recycling and reuse the waste materials and energy have been studied for the cement industry. A life cycle assessment (LCA) was performed for an alternative raw material-supply method to use the molted slag as the major raw material in the cement clinker manufacturing. Using this new method, a 60% of CO 2 could be reduced that comes out during the decarboxylation from the cement rotary kiln. The energy-efficiency improvement and the alternative energy methods that had been determined in our previous study through the environmental assessment of cement industry were applied to the study for the reduction of CO 2 emission. The natural gas, one of the fossil fuels, was also used as the first choice to get the result at the earliest time by the most economic and the most efficient green technology and to switch into the carbon neutral energy consumption pattern. Keywords : Cement, Renewable technology, Carbon dioxide, Slag, Environmental assessment, Life cycle assessment (LCA)182CLEAN TECHNOLOGY, Vol.16, No.3, September 2010, pp.182~190

Recycling process and metabolic rule of electronic waste.

Abstract: Recycling processes of waste printed circuit board (PCB) and waste cathode ray tube (CRT) were selected as research projects.The material and energy conversion model of electronic waste recycling process was established;the material flow,energy flow,waste flow and the pollutant release and transfer were analyzed;the material,energy conversion list was calculated.The energy consumption of sorting reached to 100kW?h/t,and the dismantling and the hot pressing of non-metallic materials were the key links of the emission of pollutants in the recycling process of waste printed circuit board.Energy consumption in the reuse of panel glass and funnel glass were higher than other stages,the energy consumption of preparing foam glass and smelting lead were 600 and 250kW?h/t repectively,the crushing,grinding and the smelting of lead from funnel glass were key links of the emission of pollutants in the recycling process of cathode ray tube.

Present Condition on the Recycling and Management for Waste Acids

Abstract: Environmental issues on the waste emission and its treatment are of great interest in these days. In order to resolve the pollution problems, recycling the waste materials is generally recommended. Especially, emission of waste acids in designated sources is increasing every year. In this study, we focused on the effective recycling of the waste acids rather than treatments. Management systems of the waste acids are not systematically designed, and the quality of the waste regulation on the recycling product is unclear in domestic and foreign countries. We surveyed the present conditions on domestic waste emission and recycling of waste acids. For the final analysis of the recycling products, iron chloride, iron sulfate, copper cyanide, copper oxides, and cement copper are selected as candidates. We expect that this article would help establishing the systematic management system on treating the waste acid materials.

Heavy Metal Species in Cement Products from Co-Processing Waste in Cement Kilns

Abstract: A modified Tessier sequential extraction method was conducted to study the species of heavy metals in clinker and cement paste acquired from a cement calcination simulation of raw materials mixed with heavy metal chemical reagents.The results showed that the contents of exchangeable Ni,As,Cd and Pb were very small in the clinker.Acidified sodium acetate solution in extractable form was the dominant species for Cr and Cd in the clinker,with the percentages in this form 71.0% and 95.1%,respectively.Acidified hydroxylamine hydrochloride in extractable and residual form,accounting for 65.6% and 20.3% of Ni in the clinker,were the first and second dominant species for Ni in the clinker,respectively.72.7% of Pb existed in sulfide-bound form as a solid solutions compound containing sulfur.Arsenic was mainly presented as acidified sodium acetate solution in extractable and sulfide-bound forms;these two forms accounted for 51.8% and 35.1% of As in the clinker,respectively.The species composing of heavy metals in cement paste were found to be similar to those in the clinker.This might indicate that the hydration reaction has little impact on the chemical form of heavy metals.

Economic benefits of bio-energy generation from wood waste

Abstract: Economic benefits of bio-energy generation from wood waste. The article describes the production technology of wood pellets based on a production line of medium capacity and presents basic parameters of wood pellets depending on the type of the used raw material. Economic and ecological benefits of bio-energy production using wood waste are presented. It was shown that wood pellets, as a fuel, are characterized by a low production cost per 1 kWh energy (bio-energy) in comparison to other commonly used fuels.

Paper ID : 20100986 Performance comparison of high ash Indian coal under different gasification conditions

Abstract: The increasing demand for clean fuels and climbing crude oil prices are driving oil industries to pursue the route of reducing the bottom of the barrel and alternative energy sources. Among various options available, Gasification finds an important place in the refinery to increase the refining margin as well as meeting the demand for cleaner fuels. Coal, Resid or biomass can be gasified to produce Syngas, which can be used to produce wide spectrum of products such as, clean liquid fuels, power or hydrogen. In particular, India having huge resource of coal receives wider attention. However, Indian coals are difficult to process due to its high ash content. In addition to this, the efficiency of the plant is inversely influenced by the inherent ash content in coal. This leads to the option of co-processing petroleum resids with coal to increase the efficiency of the plant. Simulation models based on basic thermodynamics are useful in analyzing different scenarios, optimization and for carrying out economic analysis for various options. Such steady state models were developed by us using ASPEN Plus for processes such as, gasification, Syngas conditioning, FT liquids production and power generation. These models are useful for studying the effect of Indian coals, petroleum resids, co-processing of various carbonaceous feedstocks, steam to oxidant ratio, process conditions, mode of feeding (dry or slurry), etc on the composition of produced syngas. These models can be used for identifying suitable gasifier configuration for processing high ash coals and can also carry out economic analysis for various co processing options such as co-production of hydrogen and power, co-production of FT liquids and power. In this paper, we present the simulation results with Indian coals for different polygeneration options and compared the efficiencies with low ash coals. The option of processing petcoke along with high ash Indian coals was also studied. Literature on high ash coals is very scarce and not readily available. In this perspective, the approach presented in this paper serves as a tool for selecting a suitable configuration for coal/resid co-processing options.