Showing papers on "Co-processing published in 2016"

Use of waste derived fuels in cement industry: a review

Abstract: Purpose – Cement production has advanced greatly in the last few decades. The traditional fuels used in traditional kilns include coal, oil, petroleum coke, and natural gas. Energy costs and environmental concerns have encouraged cement companies worldwide to evaluate to what extent conventional fuels can be replaced by waste materials, such as waste oils, mixtures of non-recycled plastics and paper, used tires, biomass wastes, and even wastewater sludge. The paper aims to discuss these issues. Design/methodology/approach – The work is based on literature review. Findings – The clinker firing process is well suited for various alternative fuels (AF); the goal is to optimize process control and alternative fuel consumption while maintaining clinker product quality. The potential is enormous since the global cement industry produces about 3.5 billion tons that consume nearly 350 million tons of coal-equivalent fossil and AF. This study has shown that several cement plants have replaced part of the fossil fu...

The Energy and Value-Added Products from Pyrolysis of Waste Plastics

Abstract: Plastic usage in daily life has increased from 5 to 100 million tons per year since the 1950s due to their light-weight, non-corrosive nature, durability and cheap price. Plastic products consist mainly of polyethylene (PE), polystyrene (PS), polypropylene (PP) and polyvinyl chloride (PVC) type plastics. The disposal of plastic waste causes environmental and operational burden to landfills. Conventional mechanical recycling methods such as sorting, grinding, washing and extrusion can recycle only 15–20 % of all plastic waste. The use of open or uncontrolled incineration or combustion of plastic waste has resulted in air and waterborne pollutants. Recently, pyrolysis technology with catalytic reforming is being used to convert plastic waste into liquid oil and char as energy and value-added products. Pyrolysis is one of the tertiary recycling techniques in which plastic polymers are broken down into smaller organic molecules (monomers) in the absence of oxygen at elevated temperatures (>400 °C). Use of catalysts such as aluminum oxides, natural and synthetic zeolites, fly ash, calcium hydroxide, and red mud can improve the yield and quality of liquid oil. The pyrolysis yield depends on a number of parameters such as temperature, heating rate, moisture contents, retention time, type of plastic and particle size. A yield of up to 80 % of liquid oil by weight can be achieved from plastic waste. The produced liquid oil has similar characteristics to conventional diesel; density (0.8 kg/m3), viscosity (up to 2.96 mm2/s), cloud point (−18 °C), flash point (30.5 °C) and energy content (41.58 MJ/kg). Char produced from pyrolysis can be activated at standard conditions to be used in wastewater treatment, heavy metals removal, and smoke and odor removal. The produced gases from pyrolysis are hydrogen (H2), carbon monoxide (CO) and carbon dioxide (CO2) and can be used as energy carriers. This chapter reviews the challenges and, perspectives of pyrolysis technology for production of energy and value-added products from waste plastics.

Exploring untapped energy potential of urban solid waste

Abstract: There is continuous increase in quantum and variety of waste being generated by anthropogenic activities. Burgeoning amount of waste being generated has potential to harm the environment and human health. Aggravating the problem, ever-increasing energy demand is putting strain on the non-renewable sources of energy and there is huge gap between the demand and supply of energy. This has led the scientific communities to adopt innovative methods to reduce, reuse and recycle them. Therefore, there is an urgent need to minimize the quantity of waste and meet the current demand profile of energy is required; technologies to recover energy from waste can play a vital role in substantial energy recovery and reduction in waste for final disposal; in addition to meet the rising energy requirement. Generating power from waste has greatly reduced the environmental impact and dependency on fossil fuels for electricity generation. Economically also it is an optimal solution for recovery of heat and power from waste. This paper gives an overview of energy potential stored in waste, major available waste-to-energy technologies and also strategic action plan for implementation of these technologies.

Effect of Variation in the Chemical Constituents of Wastes on the Co-processing Performance of the Cement Kilns

Abstract: Cement kiln co-processing is a globally practiced technology for management of different kinds of wastes in an environmentally sound and ecologically sustaining manner. Different types of wastes e.g. agro-wastes, hazardous & non-hazardous industrial wastes, combustible fractions from MSW etc are disposed off in large quantities in many cement kilns in different countries all over the world. During the treatment of wastes through co-processing, wastes get utilised as Alternative Fuels and Raw materials (AFRs) in the cement kilns. In India, cement plants have initiated co-processing of wastes and to prove the acceptability of cement kilns for their environmentally sound disposal, cement plants have implemented large number of demonstration trials on different kinds of waste streams as per the protocol prescribed by Central Pollution Control Board. Based on the critical evaluation of the results of these trials, Central Pollution Control Board endorses the acceptability for their co-processing in cement kilns. In this paper, results of such 22 demonstration co-processing trials – which were endorsed as successful by CPCB - are evaluated to understand the extent of variation present in the chemical constituents of these waste streams. It was also concluded through this evaluation that different waste streams having large variation in the chemical characteristics can be managed in an environmentally sound manner in the cement kilns.

The Sustainability of the Iron and Steel Industries in Ukraine: Challenges and Opportunities

Abstract: The iron and steel industries are indispensable components of the Ukrainian economy: throughout the decades they have provided nearly 25 % of GDP, 40 % of export revenue, 25 % of industrial production, and have employed over half a million people. Steelmaking is also the largest energy consumer of electricity and fossil fuels, being responsible for over 25 % of hazardous atmospheric emissions and over 30 % of carbon dioxide emissions from the country's industrial sources. The socio-economic, technological, and environmental aspects of sustainable industrial development have been studied based upon the data concerning mineral resources and fossil fuels, on the production facilities, on the steel consumption and export structures, etc. Current challenges, in relation to energy efficiency, the quality of raw materials, the conditions of equipment and technologies, the environmental impact, capacity utilisation, export dependency, and other factors have all been analysed. Opportunities to explore the potential of energy-saving and carbon-efficient technolo- gies, as well as for enhancing domestic steel consumption, are presented.

From waste materials to products for use in the cement industry

Abstract: Industrial wastes (bottom ash, crushed concrete fines, filter residue, paper ash and lignite fly ash) have potential for use in building materials, for instance as raw materials for clinker production, as supplementary cementitious materials (SCMs) or mineral additions in concrete. The properties of the products are dependent on the reactivity of the waste materials used, which can be classified as inert, latent hydraulic or pozzolanic. In this study, waste materials were first characterised. This was followed by theoretical considerations of the mentioned application options. Experiments were limited to evaluation of potential as SCMs and, for this purpose, activity index measurements and calorimetric and thermogravimetric analyses were performed. Finally, the synergetic effects of various waste materials were considered. Paper ash (calcium oxide source) and filter residue (amorphous silicon dioxide source) showed the best prospects for use as cementitious material components.

Utilization of waste heat from rotary kiln for burning clinker in the cement plant

Abstract: Cement subsector next to the glass industry is counted among one of the most energy-intensive industries, which absorbs approx. 12-15% of the total energy consumed by the industry. In the paper various methods of energy consumption reduction of in the cement industry are discussed. Cement production carries a very large emissions of greenhouse gases, where CO2 emissions on a global scale with the industry than approx. 5%. Great opportunity in CO2 emissions reduction in addition to the recovery of waste heat is also alternative fuels co-firing in cement kilns [1], [2]. In the cement sector interest in fitting-usable waste energy is growing in order to achieve high rates of savings and hence the financial benefits, as well as the environment ones [3]. In the process of cement production is lost irretrievably lot of energy and reduction of these losses on a global scale gives a visible saving of consumed fuel. The aim of this study is to investigate the possibility of waste heat use in Rudniki Cement Plant near to Czestochowa. After analyzing of all waste heat sources will be analyzed the heat emitted by radiation from the surface of the rotary kiln at the relevant facility. On the basis of thermal-flow calculations the most favorable radiative heat exchanger will be designed. The calculations based on available measurements provided by the cement plant, a thermal power of the heat exchanger, the heat exchange surface, the geometry of the heat exchanger, and other important parameters will be established. In addition the preliminary calculations of hydraulic losses and set directions for further work will be carried out. Direct benefits observed with the introduction of the broader heat recovery technology, is a significant increase in energy efficiency of the industrial process, which is reflected in the reduction of energy consumption and costs. Indirectly it leads to a reduction of pollution and energy consumption.

Waste heat utilisation of Croatian cement industry accounting Total Site demands

Abstract: The cement industry sector as an energy intensive industrial sector, where energy cost represents approximately 40% of the total production cost per one ton of cement, and one of the highest greenhouse gases - GHG emitting industrial sectors, accounts for around 5% of global anthropogenic GHG emissions as reported (Mikulcic et al, 2015). Considering that, the cement is the most widely used material for construction needs, this paper analyses the potential of energy efficiency improvement of the cement production for a particular cement plant in Croatia. The heat recovery potential was determined and an amount of waste heat available for utilisation accounting site wide demands are identified with use of Process Integration technique. The results show huge potential for energy saving of cement production. Different scenarios for utilization of low potential heat are proposed accounting different site demands and energy prices. Implementation of paper results helps to the cement plant’s profitability and reduces environmental impact of the cement industry.

Water footprint of widely used construction materials : steel, cement and glass

Abstract: Although water is an abundant and renewable substance on earth, the available amount of water to man is limited as the amount of precipitation, water flowing through a river or ground water aquifer is always limited in a certain time period. Furthermore, the water demand is expected to increase in the future. When water use is not properly managed this can result in unsustainable water use. After agriculture, the industrial sector is responsible for the largest amount of water withdrawal, and the water use by this sector is expected to increase. In contrast to agricultural products where quite some research has been done on the water footprint of several products, industrial products have not been researched as much. This research focusses on widely used construction materials. Five end products are chosen to be researched: unalloyed steel, chromium-nickel alloyed steel, ordinary Portland cement, Portland composite cement and sodalime float glass. These are the most produced types of steel, cement and flat glass. The water footprint concept introduced by Hoekstra takes indirect water consumption into account. This means that beside direct water consumption like cooling and cleaning water also water consumption for the input products is accounted for in the water footprint of the end product. In order to determine the water footprint of the end product the entire supply chain is considered in the research. For steel cement and glass, the supply chain begins with acquiring the raw materials. Transport of materials is left out of the scope of this research, because it is expected that the water footprint of transport is to be negligible unless biofuels are used for transportation. After acquiring the raw materials they are processed though different production processes. Some processes for the production of materials like steel, cement and glass require large amounts of energy. The supply of the fuels and generation of electricity also requires water and therefore the energy required for the production of these materials results in a water footprint which have to be allocated to the final product. Furthermore, production processes for these materials can lead to an effluent containing certain polluting substances leading to a grey water footprint. Major processes along the supply chain and their direct process water consumption are taken into account for this research leaving the water footprint tied to the energy consumption as the remaining indirect blue water footprint. The study uses existing knowledge about the blue water footprint of some energy sources. For other fuel sources, i.e. petroleum products and cokes, the blue water footprint is calculated. Depending on the fuel type used for production processes the water footprint tied to energy use can be a significant part of the total blue water footprint. Water and energy consumption data as well as pollution data is mainly obtained from the ecoinvent database version 3.2. It was found that the blue water footprint of chromium nickel alloyed steel with 77 L/kg is much larger than that of unalloyed steel with 11 L/kg. This is attributed to the energy demanding ferroalloy production which usually occurs in electric arc furnaces using electricity as energy source. For cement, clinker production by pyroprocessing is one of the most energy and water consuming processes. Reducing the ratio of clinker in cement by using supplementary materials can reduce the water footprint of cement. A blue water footprint of ordinary Portland cement was calculated between 2.0 – 2.6 L/kg, depending on the source of gypsum. For CEM II/B Portland composite cement with 21-35% supplementary materials a blue water footprint was calculated between 1.7 – 1.8 L/kg. Choosing a Portland composite cement over an ordinary Portland cement can be beneficial for minimising the water footprint of structures. For soda-lime float glass it was found that, beside the energy consuming glass melting, the Solvay process for soda ash production is a large contributing process to the water footprint of float glass. Large amounts of water is used for the Solvay process. Water uses are for brine and milk of lime production, process steam and cooling. Overall the water footprint tied to energy consumption is a significant part of the blue water footprint of the researched materials. This is attributed to the energy demanding processes and to the large water footprint of electricity. The grey water footprint of the end products is calculated per process and polluting substance by using ecoinvent version 3.2 data for effluent loads and the lowest value from maximum concentration guidelines from Canada (CCME), Europe (EU) and the United States (US-EPA) and maximum concentrations from the EEC (1975) guideline. For steel it was found that the largest grey water footprint is produced by concentrating iron ore. The grey water footprint for unalloyed steel is 2,300 L/kg steel for the polluting substance cadmium. For chromium-nickel alloyed steel the grey water footprint was found to be 1,500 L/kg steel for the polluting substance cadmium. For cement, the grey water footprint depends on whether gypsum through flue gas desulphurisation is used and whether the grey water footprint from this process is allocated to gypsum and ultimately to cement or not. If this is the case then the grey water footprint for ordinary Portland cement and Portland composite cement was found the be 210 L/kg. If the grey water footprint from flue gas desulphurisation is not applicable then the grey water footprint of ordinary Portland cement was found to be 0.63 L/kg cement for cadmium and for Portland composite 0.45 L/kg cement for cadmium. For float glass the grey water footprint is largely dependent on the Solvay process. The effluent contains heavy metals and suspended solids resulting in a grey water footprint of 1,300 L/kg glass where suspended solids are the determining material for the grey water footprint. Overall the grey water footprint is potentially much larger than the blue water footprint of the researched materials.

Hydrothermal liquefaction co-processing of wastewater sludge and lignocellulosic biomass for co-production of bio-gas and bio-oils

Abstract: This disclosure provides a process based on hydrothermal liquefaction (HTL) treatment for co-processing of high-water-content wastewater sludge and other lignocellulosic biomass for co-production of biogas and bio-crude oil. The mixture of waste activated sludge and lignocellulosic biomass such as birchwood sawdust / cornstalk / MSW was converted under HTL conditions in presence of KOH as the homogeneous catalyst. The operating conditions including reaction temperature, reaction time and solids concentration were optimized based on the response surface methodology for the maximum bio- crude oil production. The highest bio-crude oil yield of around 34 wt% was obtained by co-feeding waste activated sludge with lignocellulosic biomass at an optimum temperature of 310°C, reaction time of 10 min, and solids concentration of 10 wt%. The two by-products from this process (bio-char and water-soluble products) can be used to produce energy as well. Water-soluble products were used to produce biogas through Bio-methane Potential Test (BMP) and were found to produce around 800 mL bio-methane cumulatively in 30 days per 0.816 g of total organic carbon (TOC) or 2.09 g of chemical oxygen demand (COD) of water-soluble products.

The Property of Lime Sewage Sludgeand its Influence on Co-Processingin Cement Kilns

Abstract: In recent years, co-processing lime-dried sludge (LS) in cement kilns has attracted increasing interest in China. However, there are few published studies focused on the effect of sludge properties. In this study, LS properties and their effects on co-processing in a cement kiln were studied by performing experimental analyses and theoretical calculations. The results indicated that the heating value of municipal sewage sludge (MSS) was decreased with lime dosage. By adding 10% lime, the heating value would be almost halved to 7,198 kJ/kg. Heavy metals in LS are much lower than the limit concentration of the standard. Chlorine and sulfur are about 0.06-0.35% and 0.22-0.56%, respectively, which completely meets the relation requirement. Additionally, adding lime promotes the transformation and decomposition of ammonia and protonated amine proteins, nitrogen, and the generation of pyridine nitrogen. Theoretical calculation results show that the maximum co-processing ratio for RS is 4.5%, which can be increased by increasing the addition of a suitable amount of lime (0-16%). 10% with a 6.5% maximum co-processing ratio is suggested as the optimum lime dosage for co-combustion of LS in cement kilns.

Sustainability Assessment of Fuels Production via Hydrotreating Waste Lipids and Co-processing Waste Lipids with Petroleum Fractions

Abstract: The depletion of fossil energy resources and the increased energy consumption led to the intensification of greenhouse gas (GHG) emissions. Consequently, the investigation for renewable energy sources has focused on biofuels, aiming to the improvement of the energy security supply. Biofuels are considered alternative fuels targeting to reduce the transportation sector’s dependency on fossil resources and GHG emissions. However, the production of FAME (Fatty Acid Methyl Esters) biodiesel via transesterification of vegetable oils, raised significant issues e.g. food versus fuel debate. Catalytic hydrotreatment constitutes an alternative conversion process of vegetable oils and/or animal fats into bio-based diesel fuels and has been applied in industrial scale for the production of hydrotreated vegetable oils (HVOs). Residual biomass such as waste cooking oil (WCO) has been extensively explored as potential feedstock for renewable diesel production via catalytic hydrotreatment in CPERI/CERTH. However, considering the high investment cost of hydroprocessing units of vegetable and/or waste oils, the option of co-processing petroleum fractions with oils has recently started being investigated. More specifically, co-hydroprocessing of petroleum fractions with WCO was also examined in CPERI/CERTH, resulting in the production of a new hybrid diesel.

Hydrogen Sulphide Corrosion of Carbon and Stainless Steel Alloys Immersed in Mixtures of Renewable Fuel Sources and Tested Under Co-processing Conditions

Abstract: In accordance with modern regulations and directives, the use of renewable biomass materials as precursors for the production of fuels for transportation purposes is to be strictly followed. Even though, there are problems related to processing, storage and handling in wide range of subsequent uses, since there must be a limit to the ratio of biofuels mixed with mineral raw materials. As a key factor with regards to these biomass sources pose a great risk of causing multiple forms of corrosion both to metallic and non-metallic structural materials. To assess the degree of corrosion risk to a variety of engineering alloys like low-carbon and stainless steels widely used as structural metals, this work is dedicated to investigating corrosion rates of economically reasonable engineering steel alloys in mixtures of raw gas oil and renewable biomass fuel sources under typical coprocessing conditions. To model a desulphurising refining process, corrosion tests were carried out with raw mineral gasoline and its mixture with used cooking oil and animal waste lard in relative quantities of 10% (g/g). Co-processing was simulated by batch-reactor laboratory experiments. Experiments were performed at temperatures between 200 and 300 oC and a pressure in the gas phase of 90 bar containing 2% (m3/m3) hydrogen sulphide. The time span of individual tests were varied between 1 and 21 days so that we can conclude about changes in the reaction rates against time exposure of and extrapolate for longer periods of exposure. Initial and integral corrosion rates were defined by a weight loss method on standard size of coupons of all sorts of steel alloys. Corrosion rates of carbon steels indicated a linear increase with temperature and little variation with composition of the biomass fuel sources. Apparent activation energies over the first 24-hour period remained moderate, varying between 35.5 and 50.3 kJ mol-1. Scales developed on carbon steels at higher temperatures were less susceptible to spall and detach. Nonetheless, moderate deceleration of corrosion rates as a function of time are due to the less coherent, frequently spalling and low compactness, higher porosity of the scales evolved at lower and higher temperatures, respectively. On the surface of high alloy steels, sulphide scales of an enhanced barrier nature formed during the induction periods and the layer formation mechanism was found to be assisted by the increasing temperature as initial reaction rates considerably decreased over time. Nevertheless, corrosion-related sulphide conversion of metals and mass loss of the high alloys are strongly affected by the composition of the biomass fuel sources especially animal waste lard. Thermal activation in the first 24 hours decreased from 68.9 to 35.2 kJ mol-1. A greater degree of failure to develop protective sulphide scales was experienced by changing to composition of the biomass fuel sources than the impact of thermal activation between a narrow temperature range at around 100 oC. In accordance with the literature, high free fatty acid contents lead to high corrosion rates accounted for direct corrosion of high alloy steels and assisted solubilisation of corrosion products. In addition, the pronounced acceleration of sulphide corrosion is connected to the diminishing inhibition effect of the sulphide scales.

Sustainable Use of Industrial Waste in Cement Industry

Abstract: Environment and economic considerations demand greater utilization of the waste. Cement industry is a major contributor in the emission of CO2 as well as in using up high levels of energy resources in the production of cement. On the other hand productions of large quantities of industrial wastes are resulting in environmental problems with its dumping. Industrial wastes contain some toxic elements and releases into the environment under natural weathering conditions. These toxic elements cause pollution of soils, surface waters and groundwater. The use of theses industrial waste as substitute of cement, control the emission of CO2 and also control the environmental problems associated with its dumping. Industrial wastes, such as copper slag, blast furnace slag, granulated phosphorus slag and steelmaking slag are being used as supplementary cement replacement materials. These wastes exhibit not only good strength properties but also better corrosion resistance than normal Portland cement. The conversion of industrial waste in to cement required the grinding, which needs only approximately 10% of the energy required for the production of Portland cement. Thus industrial waste has great potential in cement industry. In this paper, the recent achievements in the development of high performance cementing materials using different industrial wastes are reviewed.

The Use of Lime for Carbon Dioxide Production: Brief Analysis

Abstract: Nowadays, the selection of construction materials depends not only on the economic or resistance characteristics but also the environmental effect, mainly for the energy usage, CO 2 emissions and pollution produced during the processes to obtain them. Portland cement and lime can be used to produce solid vertical structures. Poured earth is a technique that can substitute concrete or cement mortars in edification, characterized by using less inorganic materials as cement, and soil of the surrounding environment. This paper proposes a method to analyze the use of lime and cement in solid, and show the basic analysis of lime and explain why it is impossible to have a 100% ecological product or renewable, but also it is possible to reduce emission with decrease of products according to the desired characteristic of the final material produced.