Bacteria that effectively transform plastic waste into a useful eco-friendly plastic:

Bacteria that effectively transform plastic waste into a useful eco-friendly plastic:

In response to problems associated with plastic waste and its effect on the environment, there has been considerable interest in the development and production of biodegradable plastics. Innumerable amount of research have also been conducted world wide to find out ways to convert synthetic plastic waste into biodegradable and compostable material. Their effort was to isolate bacterium that can effectively convert a waste plastic product into safe, biodegradable product or to make safe and biodegradable plastic, which can be used safely for further manufacture of some product.

A. It has been observed that, chemicals called Polyhydroxyalkanoates (PHAs) are polyesters that accumulate as inclusions in a wide variety of bacteria. These bacterial polymers have properties ranging from stiff and brittle plastics to rubber-like materials. Because of their inherent biodegradability, PHAs are regarded as an attractive source of nonpolluting plastics and elastomers that can be used for specialty and commodity products. They were the first biodegradable polyesters to be utilised in plastics. These aliphatic polyesters naturally produced via a microbial process on sugar-based medium. The two main members of the PHA family are polyhydroxybutyrate (PHB) and polyhydroxyvalerate (PHV).

B. There is good news that, recently some European scientists have discovered a bacterial strain that uses styrene, a toxic byproduct of the polystyrene industry, as fuel to make Polyhydroxyalkanoate (PHA) - biodegradable plastic. The microbes, a special strain of the soil bacterium Pseudomonas putida, convert polystyrene foam — commonly known as Styrofoam — into PHA, a biodegradable plastic. This is among the first to investigate the possibility of converting a petroleum-based plastic waste into a reusable biodegradable form.

Researchers utilized pyrolysis, a process that transforms plastic waste materials by heating them in the absence of oxygen, to convert polystyrene — the key component of many disposable products — into styrene oil. The researchers then supplied this oil to Pseudomonas putida, a bacterium that can feed on styrene, which converted the oil into PHA. The process might also be used to convert other types of discarded plastics into PHA.

C. PHA has numerous applications in medicine and can be used to make plastic kitchenware, packaging film and other disposable items as well. This biodegradable plastic is resistant to hot liquids, greases and oils, and can have a long shelf life. The advantageous side of PHA is unlike polystyrene, it readily breaks down in soil, water, septic systems and backyard composts. In other words, it is biodegradable and compostable.

D. Worldwide, more than 14 million metric tons of polystyrene are produced annually, most of this ends up in landfills producing pollution. Thus, this system can help transform plastic waste into a useful eco-friendly plastic, significantly reducing the environmental impact of this ubiquitous, but difficult-to-recycle waste stream.

A pollution-free coal based electric power plant – Futuristic view and Skepticism:

A pollution-free coal based electric power plant – Futuristic view and Skepticism:

Coal is the workhorse of global electric power sector and is used to generate more than half of the electricity world consumes. It is also world’s most abundant fossil fuel, with supplies projected to last almost 250 years or more. As coal-fired power plants generally produce the lowest-cost electricity and coal is abundant, most of the country’s economic and energy security depend on the continued use of the fuel. But most disadvantage part of this fuel is: coal is an inherently dirty fuel; it contains more pollutants than oil or gas, and burning coal or any fossil fuel releases the pollutants into the atmosphere. Fossil-fuel combustion also releases carbon dioxide, the primary greenhouse gas that causes global warming.

A. One way to clean the electric power generation system is to separate out carbon at the point of combustion and capture and isolate it in a process known as sequestration. Sequestration techniques now under study range from injecting CO2 underground or deep into the ocean to having forests absorb the gas. One objective of the, much talked about, ‘FutureGen’ project is to explore the feasibility of several of these techniques. High cost of sequestration technology is the most intriguing factor, at present. As per the estimation of DOE (Department of Energy of Federal Govt. of US) the cost of sequestration using existing technologies is in the range of $100 to $300/ton of carbon emissions. A goal of the FutureGen program (FutureGen's developers - an alliance of a dozen big power and coal companies such as American Electric Power Inc., BHP Billiton, Consol Energy Inc., Foundation Coal Corp., Peabody Energy Corp. and Rio Tinto Energy etc.) is to employ advanced technologies to reduce that figure to $10 or less by 2015.

B. Facts about the program – a discussion:

(i) Coal gasification is a mature technology in the chemicals industry, which uses the process to create feedstock for ammonia and other chemicals and fine chemicals.

(ii) For generating electricity, this technology has not yet been fully used by industry. In fact, the most economical way to make hydrogen is from methane natural gas.

(iii) In case of extracting hydrogen from coal, 30% of fuel’s latent energy is lost.

(iv) It is expected to initially capture at least 90% of the CO2 that system produces; adding that advanced technologies could eventually achieve nearly 100% capture.

(v) Once captured, the CO2 will be injected deep underground.

(vi) Potential graves include saline aquifers thousands of feet below the surface, depleted oil or gas reservoirs, and unmineable coal seams or basalt formations.

(vii) Once buried, the greenhouse gas would have little chance of escaping into the atmosphere.

C. Skepticism about the program – a discussion:

(i) It's easier to eliminate the pollutants in coal such as nitrogen oxides (NOX) and sulfur dioxide (SO2) at the front end than at the back, where they end up dispersed in flue gas.

(ii) The plan is to clean SO2 and NOx from the coal gases and convert them to byproducts such as fertilizers and soil enhancers.

(iii) Mercury also would be removed, and CO2 would be captured and sequestered in deep, underground geologic formations.

(iv) People are coming to the realization that making sequestration work is going to be very expensive and efficiency of removal of SO2 and NOx.

(v) There was no guarantee of carbon sequestration technology that rock formations, destined for the carbon, would seal-in the offending material.

(vi) We may have to spend billions and billions of dollars chasing technology that, even when perfected, is not nearly as perfect as the renewable energy (such as wind, solar, geothermal) in creating energy that gives us the added benefit of saving our environment.

‘Carbon sequestration’ - Greatest challenge of clean coal technology (‘FutureGen’ project) to deliver "zero emissions" in reality:

‘Carbon sequestration’ - Greatest challenge of clean coal technology (‘FutureGen’ project) to deliver "zero emissions" in reality:

A present trend of clean coal technology is moving rapidly towards a very interesting phase, realizing efficiency improvements of coal. In fact, this clean coal technology together with the use of natural gas and renewables such as wind will not provide the deep cuts in greenhouse gas emissions necessary to meet future national targets. Naturally, a plant to produce hydrogen from coal and sequester emissions will be the world’s zero emission coal-fired plant – as envisaged for ‘FutureGen’ project.

As discussed earlier, the clean coal technology field is moving in the direction of coal gasification with a second stage so as to produce a concentrated and pressurized carbon dioxide stream followed by its separation and geological storage. This technology has the potential to provide what may be called "zero emissions" - in reality, extremely low emissions of the conventional coal pollutants, and as low-as-engineered carbon dioxide emissions.

A. The greatest challenge now is to sequester emissions by carbon capture and geological storage technology. The technology, known as carbon sequestration, has attracted global attention from industries and governments that are eager to capture and bottle up the gas that can linger in the atmosphere for decades.

B. Carbon capture and sequestration begins with the separation and capture of CO₂ from power plant flue gas and other stationary CO₂ sources. At present, this process is costly and energy intensive, accounting for the majority of the cost of sequestration. However, analysis shows the potential for cost reductions of 30–45 percent for CO₂ capture. Post-combustion, pre-combustion, and oxy-combustion capture systems being developed are expected to be capable of capturing more than 90 percent of flue gas CO₂.

C. The primary function of carbon sequestration research and development (R&D) objectives are:

(1) Lowering the cost and energy penalty associated with CO₂ capture from large point sources; and

(2) Improving the understanding of factors affecting CO₂ storage permanence, capacity, and safety in geologic formations and terrestrial ecosystems.

D. After capturing of carbon the next step is to sequester (store) the CO_2; which has mainly two processes - (i) The primary means for carbon storage are injecting CO₂ into geologic formations or (ii) using terrestrial applications.

(i) Geologic sequestration involves taking the CO₂ that has been captured from power plants and other stationary sources and storing it in deep underground geologic formations in such a way that CO₂ will remain permanently stored. Geologic formations such as oil and gas reservoirs, unmineable coal seams, and underground saline formations are potential options for storing CO₂. Storage in basalt formations and organic rich shales is also being investigated.

(ii) Another form of sequestration is ‘terrestrial sequestration’, which involves the net removal of CO₂ from the atmosphere by plants and microorganisms that use CO₂ in their natural cycles. Terrestrial sequestration requires the development of technologies to quantify with a high degree of precision and reliability the amount of carbon stored in a given ecosystem.

E. Any carbon sequestration program should involve (a) Core R&D, and (b) Demonstration & Deployment.

(a) Core R&D – Core R&D accomplished through laboratory and pilot-scale research, develops new technologies and systems for reducing greenhouse gas emissions from industrial sources. Core R&D integrates basic research and computational sciences to study advanced materials and energy systems. It focuses on few major areas for technology development: (i) CO₂ Capture, (ii) Carbon Storage, (iii) Monitoring, Mitigation, and Verification, (iv) Non-CO₂ Greenhouse Gas Control, and (v) Breakthrough Concepts.

(b) Demonstration & Deployment – It speeds the development of new technologies through commercial opportunities and collaboration with Govt. departments. Core R&D scientists also learn practical lessons from these demonstration projects and are helpful to develop further technology solutions and innovations.

As mentioned above, this system along with use of natural gas and renewable energy sources such as wind, solar etc., will be advantageous in order to mitigate to a great extent in greenhouse gas emissions necessary to meet future national targets. Many countries see "zero emissions" coal technology as a core element of its future energy supply in a carbon-constrained world. They have program to develop and demonstrate the technology and have commercial designs for plants with an electricity cost of only 10% greater than conventional coal plants available by 2012. Australia is very well endowed with carbon dioxide storage sites near major carbon dioxide sources, but as elsewhere, demonstration plants will be needed to gain public acceptance and show that the storage is permanent. In general, "zero emissions" technology seems to have the potential for low avoided cost for greenhouse gas emissions.

‘FutureGen’ project - to design, build and operate a nearly emission-free coal-based electricity and hydrogen:

‘FutureGen’ project - to design, build and operate a nearly emission-free coal-based electricity and hydrogen:

The clean coal technology field is moving very rapidly in the direction of coal gasification with a second stage so as to produce a concentrated and pressurised carbon dioxide stream followed by its separation and geological storage. At present the high cost of carbon capture and storage renders the option uneconomic. But a lot of work is being done by many of the research institutes, to improve the economic viability of this system.

More recently department of energy (DOE) of Federal Govt. of the USA has announced ‘FutureGen’ project to design, build and operate a nearly emission-free coal-based electricity and hydrogen production plant. It will use cutting-edge technologies to generate electricity while capturing and permanently storing carbon dioxide deep beneath the earth. The integration of these technologies is what makes FutureGen unique. Researchers and industry have made great progress advancing technologies for coal gasification, electricity generation, emissions control, carbon dioxide capture and storage, and hydrogen production. But these technologies have yet to be put together and tested at a single plant - an essential step for technical and commercial viability.

Therefore, the FutureGen initiative would have comprised a coal gasification plant with additional water-shift reactor, to produce hydrogen and carbon dioxide. About one million tones of CO₂ would then be separated by membrane technology and sequestered geologically. The hydrogen would have been be burned in a power generating plant and in fuel cells. The project was designed to validate the technical feasibility and economic viability of near-zero emission coal-based generation. Construction of FutureGen was due to start in 2009, for operation in 2012.

Coal gasification processes –

(a) In conventional plants coal, often pulverised, is burned with excess air (to give complete combustion), resulting in very dilute carbon dioxide at the rate of 800 to 1200 g/kWh.

(b) Gasification converts the coal to burnable gas with the maximum amount of potential energy from the coal being in the gas.

(c) In Integrated Gasification Combined Cycle (IGCC) the first gasification step is pyrolysis, from 400°C up, where the coal in the absence of oxygen rapidly gives carbon-rich char and hydrogen-rich volatiles.

(d) In the second step the char is gasified from 700°C up to yield gas, leaving ash. With oxygen feed, the gas is not diluted with nitrogen.

(e) The key reactions today are C + O₂ to CO, and the water gas reaction: C + H₂O (steam) to CO & H₂ - syngas, which reaction is endothermic.

(f) In gasification, including that using oxygen, the O₂ supply is much less than required for full combustion, so as to yield CO and H₂.

(g) The hydrogen has a heat value of 121 MJ/kg - about five times that of the coal, so it is a very energy-dense fuel.

(h) However, the air separation plant to produce oxygen consumes up to 20% of the gross power of the whole IGCC plant system.

(i) This syngas can then be burned in a gas turbine, the exhaust gas from which can then be used to raise steam for a steam turbine, hence the "combined cycle" in IGCC.

(j) To achieve a much fuller clean coal technology in the future, the water-shift reaction will become a key part of the process so that:

(i) C + O₂ gives CO, and

(ii) C + H₂O gives CO & H₂, then the

(iii) CO + H₂O gives CO₂ & H₂ (the water-shift reaction).

(k) The products are then concentrated CO₂ which can be captured, and hydrogen. (There is also some hydrogen from the coal pyrolysis), which is the final fuel for the gas turbine.

(k) Overall thermal efficiency for oxygen-blown coal gasification, including carbon dioxide capture and sequestration, is about 73%.

(l) Using the hydrogen in a gas turbine for electricity generation is efficient, so the overall system has long-term potential to achieve an efficiency of up to 60%.

‘Clean Coal Technology (CCT)’ – methods to remove pollutants from coal.

‘Clean Coal Technology (CCT)’ – methods to remove pollutants from coal.

Carbon dioxide from burning coal is the main focus of attention today, since it is implicated in global warming, and the Kyoto Protocol requires that emissions decline, notwithstanding increasing energy demand.

A. Capture & separation of Carbon dioxide - A number of means exist to capture carbon dioxide from gas streams, but they have not yet been optimised for the scale required in coal-burning power plants. The focus has often been on obtaining pure CO₂ for industrial purposes rather than reducing CO₂ levels in power plant emissions. Capture of carbon dioxide from flue gas streams following combustion in air is expensive as the carbon dioxide concentration is only about 14% at best. This treats carbon dioxide like any other pollutant and as flue gases are passed through an amine solution the CO₂ is absorbed. It can later be released by heating the solution. This amine scrubbing process is also used for taking CO₂ out of natural gas. There is an energy cost involved. Captured carbon dioxide gas can be put to good use, even on a commercial basis, for enhanced oil recovery. Injecting carbon dioxide into deep, unmineable coal seams where it is adsorbed to displace methane (effectively: natural gas) is another potential use or disposal strategy.

B. Coal arriving at a power plant contains mineral content that needs to be removed, in order to make it clean, before it is burnt. A number of processes are available to remove unwanted matter and make the coal burn more efficiently.

(a) Coal cleaning by washing - Coal washing involves grinding the coal into smaller pieces and passing it through a process called gravity separation. One technique involves feeding the coal into barrels containing a fluid that has a density which causes the coal to float, while unwanted material sinks and is removed from the fuel mix. The coal is then pulverised and prepared for burning.

(b) Gasification of coal – The Integrated Gasification Combined Cycle (IGCC) plant is a means of using coal and steam to produce hydrogen and carbon monoxide (CO) which are then burned in a gas turbine with secondary steam turbine (ie combined cycle) to produce electricity.

Coal gasification plants are favoured by some because they are flexible and have high levels of efficiency. The gas can be used to power electricity generators, or it can be used elsewhere, i.e. in transportation or the chemical industry. In Integrated Gasification Combined Cycle (IGCC) systems, coal is not combusted directly but reacts with oxygen and steam to form a "syngas" (primarily hydrogen). After being cleaned, it is burned in a gas turbine to generate electricity and to produce steam to power a steam turbine. Coal gasification plants are seen as a primary component of a zero-emissions system. However, the technology remains unproven on a widespread commercial scale.

(c) Removing pollutants from coal - Burning coal produces a range of pollutants that harm the environment: Sulphur dioxide (acid rain); nitrogen oxides (ground-level ozone) and particulates (affects people's respiratory systems). There are a number of options to reduce these emissions:

(i) Sulphur dioxide (SO2) - Flue gas desulphursation (FGD) systems are used to remove sulphur dioxide. "Wet scrubbers" are the most widespread method and can be up to 99% effective. A mixture of limestone and water is sprayed over the flue gas and this mixture reacts with the SO2 to form gypsum (a calcium sulphate), which is removed and used in the construction industry.

(ii) Nitrogen oxides (NOx) - NOx reduction methods include the use of "low NOx burners". These specially designed burners restrict the amount of oxygen available in the hottest part of the combustion chamber where the coal is burned. This minimises the formation of the gas and requires less post-combustion treatment.

(iii) Particulates emissions - Electrostatic precipitators can remove more than 99% of particulates from the flue gas. The system works by creating an electrical field to create a charge on particles which are then attracted by collection plates. Other removal methods include fabric filters and wet particulate scrubbers.

Clean coal technology (CCT) – To mitigate Global warming and climate change - A discussion

Clean coal technology (CCT) – To mitigate Global warming and climate change - A discussion

Coal when burned is the dirtiest of all fossil fuels. A range of technologies are being used and developed to reduce the environmental impact of coal-fired power stations. Thus, clean coal technology (CCT) is the name attributed to coal chemically washed of minerals and impurities, sometimes gasified, burned and the resulting flue gases treated with steam with the purpose of removing sulfur dioxide, and reburned so as to make the carbon dioxide in the flue gas economically recoverable.

A. It is a known fact that, the burning of coal, a fossil fuel, is the principal causes of anthropogenic climate change and global warming. In fact, the byproducts of coal combustion are very hazardous to the environment if not properly contained. This is seen to be the technology's largest challenge, both from the practical and public relations perspectives. While it is possible to remove most of the sulfur dioxide (SO2), nitrogen oxides (NOx) and particulate (PM) emissions from the coal-burning process, carbon dioxide (CO2) emissions will be more difficult to address. Therefore, fact regarding the coal remains:

(a) Coal is a vital fuel in most parts of the world.

(b) Burning coal without adding to global carbon dioxide levels is a major technological challenge which is being addressed.

(c) The most promising "clean coal" technology involves using the coal to make hydrogen from water, then burying the resultant carbon dioxide by-product and burning the hydrogen.

(d) The greatest challenge is bringing the cost of this down sufficiently for "clean coal" to compete with nuclear power on the basis of near-zero emissions for base-load power.

B. In relation to clean coal technology, a terminology ‘carbon capture and storage’ (CCS) is being discussed. CCS is nothing but method of capturing the carbon dioxide, preventing the greenhouse gas entering the atmosphere, and storing it deep underground by various ways, such as

(a) CO2 pumped into disused coal fields displaces methane which can be used as fuel,

(b) CO2 may be pumped into and stored safely in saline aquifers, or

(c) CO2 pumped into oil fields helps maintain pressure, making extraction easier.

A range of approaches of CCS have been developed and have proved to be technically feasible. They have yet to be made available on a large-scale commercial basis because of the costs involved.

C. Clean coal technologies are continually developing. Today, efficiencies of 46% can be achieved by implementing the best available technology. With further research into techniques such as Ultra-supercritical combustion, efficiencies above 50% are envisaged in the near future. Work is underway to exploit the opportunities of capturing and storing CO2, which is an inevitable by-product of the thermal use of all fossil fuels. Coupled with integrated gasification, coal could in this way provide a source of low-carbon hydrogen for fuelling transport without producing local emissions. There will be challenges in bringing these technologies to market, but with the right mix of research investment and market incentives, coal may stake a place in a sustainable and secure energy future.

D. To summarise, burning coal, such as for power generation, gives rise to a variety of wastes which must be controlled or at least accounted for. So-called "clean coal" technologies are a variety of evolving responses to late 20th century environmental concerns, including that of global warming due to carbon dioxide releases to the atmosphere. However, many of the elements have in fact been applied for many years, and they will be only briefly mentioned here:

(i) Coal cleaning by 'washing' has been standard practice in developed countries for some time. It reduces emissions of ash and sulfur dioxide when the coal is burned.

(ii) Electrostatic precipitators and fabric filters can remove 99% of the fly ash from the flue gases - these technologies are in widespread use.

(iii) Flue gas desulfurisation reduces the output of sulfur dioxide to the atmosphere by up to 97%, the task depending on the level of sulfur in the coal and the extent of the reduction. It is widely used where needed in developed countries.

(iv) Low-NOx burners allow coal-fired plants to reduce nitrogen oxide emissions by up to 40%. Coupled with re-burning techniques NOx can be reduced 70% and selective catalytic reduction can clean up 90% of NOx emissions.

(v) Increased efficiency of plant - up to 45% thermal efficiency now (and 50% expected in future) means that newer plants create less emissions per kWh than older ones.

(vi) Advanced technologies such as Integrated Gasification Combined Cycle (IGCC) and Pressurised Fluidised Bed Combustion (PFBC) will enable higher thermal efficiencies still - up to 50% in the future.

(vii) Ultra-clean coal from new processing technologies which reduce ash below 0.25% and sulfur to very low levels mean that pulverised coal might be fed directly into gas turbines with combined cycle and burned at high thermal efficiency.

(viii) Gasification, including underground gasification in situ, uses steam and oxygen to turn the coal into carbon monoxide and hydrogen.

(ix) Sequestration refers to disposal of liquid carbon dioxide, once captured, into deep geological strata.

E. Discussion - Many experts think, the concept of clean coal is said to be a solution to climate change and global warming. Whereas, environmental groups believe it is nothing but another way of making everybody fool, in other words, it is ‘green-wash’. Environmentalists say, with this technology emission and wastes are not avoided, but are transferred from one waste stream to another. They opine that, coal can never be clean. Critics of the planned power plants assert that there is no such thing as "clean coal" and that the plant will still release large amounts of pollutants compared to renewable energy sources such as wind power and solar power. A good deal of investment in research and development and also in implementation of pollutant free renewable energy (such as wind power and solar power) has to augmented, to make the world very clean, to make the required electricity generation fully green.

Emerging trends in improving Blast Furnace (BF) performance of ironmaking – More environment-friendly and cost effective proposition:

Emerging trends in improving Blast Furnace (BF) performance of ironmaking – More environment-friendly and cost effective proposition:

Blast furnace (BF) technology is the central to the crude steel industry and is continually undergoing refinements to improve productivity and reduce operating costs. Continuous improvements in productivity, coke consumption and fuel use within steel works have been driven by competition in world steel market.

The major raw materials generally used in blast furnace technology are high quality of iron ore (lumps, sintered or pallets), coal (ranging from coke to coking coal) as fuel, limestone and dolomite as fluxing materials.

A. At present, the real challenge in ironmaking industry by blast furnace lies to ensure that each process meets the emission limits prescribed by law and for that purpose each process is to examine for (a) use of energy, (b) use of material, (iii) waste generation for the entire life cycle of the project. These factors are believed to be root cause of environmental degradation. Some the processes which can economize on energy, process waste and material inputs are:

(i) High temperature hot blast technology for Blast Furnaces for lower energy consumption.

(ii) Cast House Slag Granulation Technology for utilizing Blast Furnace slag.

(iii) Ceramic welding technology for increasing life and reducing energy loss in coke oven.

(iv) Bell-less top technology for BF for increasing productivity and reducing coke rate.

(v) Continuous casting technology for reducing energy consumption and process waste in steel casting.

(vi) Water treatment technologies for economical water management.

B. As mentioned, coal / coke is an important raw material, which constitutes about 42% of the cost of sales and 58% of the raw material cost of an Integrated Steel Plant. The conventional blast furnace route of iron making needs prime coking coal. In order to reduce the cost of fuel (coke) and to use more of coking or non-coking coal replacing most of coke, many of the emergent technologies have been developed and tried. Many of these coals, extractable through lowcost mining, can be injected directly through the tuyeres of blast furnaces, substituting good quality coke in a very cost-effective manner.

C. In one example, during the implementation of improved method of coal injection to blast furnace, this inferior coal replaces almost same weight of blast furnace grade coke, which is produced from almost one and one-half unit of prime coking coal (at more than double the cost), after carbonization for several hours at substantial processing cost. The coke ovens are very capital intensive and pollute the atmosphere. Thus, coal injection not only reduces the operating cost, but also saves capital expenditure substantially, while maintaining greener and cleaner environment. More important and helpful to the blast furnace (BF) operator is that it facilitates operational stability and optimization by providing endothermic heat to control the combustion. There are two modes of coal injection:

(a) The pulverized coal injection (PCI) and

(b) The granular coal injection (GCI).

Most of the newly constructed blast furnaces generally have installed PCI, a very common technology available everywhere. However, the existing blast furnaces with no injection facilities can go for GCI, which is less energy intensive and more environment friendly. The savings using appropriate variety of low cost non-coking coal would be of the order of about US$ 4 to 6 million per annum per blast furnace of 1 Mtpa capacity.

Experts opine that, for coal injection, GCI is emerging as a more cost effective and energy efficient technology.

D. The advantage of GCI over PCI is given here:

(i) Reduction in coal preparation costs due to low energy consumption (GCI: 20kWh/t, PCI: 32kWh/t);

(ii) Easier to handle in pneumatic conveying systems since granular coal is less sticking to the conveying pipe.

(iii) System availability is more;

(iv) Granular coal’s coarseness delays gas evolution and temperature rise associated with coal combustion in the raceway. Therefore, it is favorable compared to PCI because of less likely generation of high temperature and gas flows at the furnace walls, which results in high heat losses, more refractory wear and poor utilization of reducing gases;

(v) Granular injection system is superior while using low volatile coal to avoid line plugging and other related problems. Thus, the use of granular coal may increase the range of coals available for blast furnace injection.

(vi) There is a significant economic advantage to using granular coal over pulverized coal, since not only is less grinding equipment required resulting in capital savings, but operating costs are also reduced as approximately 60% less grinding energy is required for granular coal. Capital including infrastructure costs for GCI are lower than those for PCI. (PCI ~ US$ 43,000 whereas GCI ~ US$ 37,500 per daily ton of injected coal).

Environment-friendly COREX®, FINEX® and MIDREX® Ironmaking processes – Essential in today’s changing scenario – A discussion:

Environment-friendly COREX®, FINEX® and MIDREX® Ironmaking processes – Essential in today’s changing scenario – A discussion:

A. Global demand for iron and steel is constantly growing, while at the same time prices for raw materials, energy, and transport continue to increase. At the same time, the requirements of iron making processes are to go compatible with the present ecology and environmental criteria of the region. In this dynamic environment completely new strategies are required for both iron making plant builders and operators. New ironmaking processes have been extensively explored with a view to saving resources and energy, as well as reducing environmental pollution.

Therefore, certain criteria processes should follow, such as:

(a) Full range of cutting-edge solutions in the iron and steelmaking sector,

(b) Increased environmental protection and optimized processes for economical production,

(c) Processes with extended raw material flexibility to encounter increasing raw material availability and cost.

The present scenario of iron and steel sector is very much challenging. Consolidation of the iron and steel branches manifested itself in a significant increase of mergers and takeovers. Nevertheless, the global iron and steel industry continues to expect strong growth. According to the latest analysis, demand for steel will grow by up to 25% by the year 2015, mainly due to rapid economic development in the highly populated Asian countries. In addition to transport and logistics, above all, raw materials and energy are the global driving forces behind the market’s dynamics. Energy costs will also continue to increase.

Growing environmental consciousness also contributes to market dynamics by prompting construction of plants that meet increasingly stringent environmental standards. However, existing plants that produce hot metal must continue to optimize their consumption parameters in the future to achieve increased quality with constant or even lowered operation costs. This is the only way they will be able to strengthen their market performance over the long term. Exact analyses required to keep an overview of this complex market. These include analyses of raw material and energy, feasibility studies and examinations of environmental performance. Today a plant for hot metal and/or DRI production is much more than just a plant. It is part of the entire value added chain in iron and steel production.

B. Today, direct smelting is a much sought-after prize. The traditional blast furnace route for ironmaking is coming under increasing pressure - environmental and economic. Many have tried to develop direct smelting technologies, but the challenge appears to be particularly difficult, certainly more so than one might expect. Out of many processes following three are considered to be most environment-friendly technology for ironmaking: (a) COREX® technology, (b) FINEX® technology, (c) MIDREX® technology.

(a) COREX® technology – It is an industrially and commercially proven direct smelting reduction process that allows for cost-efficient and environmentally compatible production of hot metal directly from iron ore and non-coking coal. This is the only alternative to the conventional blast furnace route consisting of sinter plant, coke oven and blast furnace. It distinguishes itself from the blast furnace route by: (i) Direct use of non-coking coal as reducing agent and energy source and (ii) Iron ore can be directly and feasibly charged to the process in form of lump ore, pellets and sinter.

In this technology, iron ore (lump ore, pellets, sinter or a mixture thereof) are charged into a reduction shaft where they are reduced to direct reduced iron (DRI) by a reduction gas moving in counter flow. Discharge screws convey the DRI from the reduction shaft into the melter gasifier, where final reduction and melting takes place in addition to all other metallurgical reactions. Hot metal and slag tapping are done as in conventional blast furnace practice. Coal is directly charged into the melter gasifier. Coal combustion by oxygen injected into the melter gasifier results in the generation of a highly efficient reduction gas. This gas exits the melter, is cooled and is then blown into the reduction shaft, reducing the iron ores in counter flow to DRI, as described above. The gas leaving the reduction shaft is cooled and cleaned and is suitable for a wide range of applications (e.g., power generation, DRI production or use in reheating furnaces).

Benefits of this process -

(i) Substantially reduced specific investment costs and operation costs compared with conventional blast furnace route,

(ii) Outstanding overall environmental compatibility, as less carbon dioxide is produced;

(iii) Use of COREX export gas for a wide range of applications,

(iv) Use of a wide variety of iron ores and coals,

(v) Elimination of coking plants,

(vi) Hot-metal quality suitable for all steel applications.

COREX process of iron making is in operation at (i) Mittal Steel South Africa, Saldanha Steel Works, South Africa; (ii) Jindal South West Steel, Toranagallu Works, India; (iii) Posco, Pohang Works, Korea; (iv) Baosteel, China (v) Essar steel, India etc.

(b) FINEX® technology – It is an optimized fine-ore reduction process for the direct utilization of the world's vast resources of low-cost iron ore fines for the production of iron. The FINEX® smelting-reduction process based on the direct use of non-coking coal and fine ore is perhaps the most exciting iron making technology on the market today. This is a process with great potential with regard to productivity and the low cost production of hot metal.

In this process fine iron ore is preheated and reduced to fine direct reduced iron (DRI) in a three or four stage fluidized bed reactor system. The upper reactor stage serves primarily as a preheating stage. In the succeeding stages the iron ore is progressively reduced to fine DRI. The fine DRI will be compacted and then charged in the form of hot compacted iron (HCI) into the melter gasifier. The charged HCI is subsequently reduced to metallic iron and melted. The heat needed for the metallurgical reduction work and the melting is supplied by coal gasification with oxygen. The reduction gas, also produced by the coal gasification, is passed through the fluidized bed reactors. The generated FINEX export gas is a highly valuable product and can be further used for DRI/HBI production, electric energy generation or heating purposes.

Benefits of this process -

(i) Favorable economics in comparison to the blast furnace route,

(ii) Environmental benefits due to savings in resources and energy, as well as lower emissions,

(iii) Direct utilization of non-coking coal,

(iv) High valuable export gas for a wide range of applications in metallurgical processes and energy production,

(v) Production of hot metal with similar quality to the blast furnace,

(vi) Reduction of process steps.

FINEX process of iron making is in development / trial-operation stage at Posco, Pohang Works, Korea.

(c) MIDREX® technology – This is a natural gas based shaft furnace process that converts iron oxides in the form of pellets or lump ore into direct reduced iron (DRI).

Benefits of this process -

(i) Fastest start-up, (ii) Simple operation, (iii) Low pressure shaft furnace etc.

MIDREX process of iron making is in operation at Saudi Iron and Steel Company Ltd. (HADEED), Al-Jubail, Saudi Arabia.

C. Discussion: Now the fact is, blast furnace steelmakers, as a group, are only too aware that they are under considerable pressure. Environmental issues with coke ovens and sinter plants continue to plague them, and periodic blast furnace re-lines (in some cases costing a significant proportion of what a new direct smelting plant might cost) continually force re-examination of alternatives. For most, margins are already thin and capital investments needed to address individual environmental issues are not sufficiently attractive. The temptation is to hold off until a decision on the next significant reline falls due, or coke ovens have to be replaced, then assess whether or not a new 'clean' solution, such as direct smelting is more cost-effective.

What benefits would a steelmaker in this situation hope to achieve from direct smelting? In my opinion, the wish-list might be: (i) Ability to use iron ore fines directly, without the need to sinter or pelletise. This will make environmental issues currently associated with sinter plants disappear. (ii) Ability to use coal directly, with no coking or other thermal pre-treatment. Environmental concerns related to coke ovens will vanish as a result. (iii) Ability to use iron ore with higher phosphorus levels, leading to increased iron ore reserves. (iv) Coal consumption rates better than or comparable to those of the blast furnace, leading to similar (or lower) carbon dioxide emissions. (v) Single-train capacities which can sensibly replace a blast furnace, in the range 1.5-4.0 Mt/a. (vi) Ability to recycle iron-bearing wastes.

Therefore, the challenge to the direct smelting technology provider is to tackle most of the above problems faced by steel makers and make the process more compatible with greener environment standards with better economy.

World Environment Day:

World Environment Day:

United Nations General Assembly in1972 established the World Environment Day (WED). On the same day United Nations Environment Programme (UNEP) was created too. Today World Environment Day is celebrated world over in many ways. World Environment Day (WED) is not just another day but a special day about you and me. Green concerts, essay and poster competitions, rallies, tree planting, recycling efforts, clean-up campaigns etc. are some of the ways people, organisations and the governments express their concern towards the environment. WED is also used to enhance political attention and action. Pledges are made and actions are taken, which lead to the establishment of permanent governmental structures dealing with environmental management and economic planning. WED is hosted every year by a different city and commemorated with an international exposition through the week of June 5.

The United Nations Environment Programme (UNEP) has announced the 2008 World Environment Day events will be held in New Zealand. New Zealand is one of the first countries to pledge a carbon-neutral future, demonstrating their readiness to find solutions to Climate Change impacts.

The focus of the global 2008 celebrations will be on the solutions and the opportunities for countries, companies and communities to de-carbonize their economies and changing habits of present life-styles towards low carbon economy for achieving cleaner environment.

We should not think that, investment in environment-friendly technologies is a burden. On the other hand, it is our moral, social, and legal obligation we must fulfill. Moreover, it makes good business sense in the medium and long term. Wherever possible - and it is possible in many cases - we should also implement low cost green technologies that are appropriate to our needs and conditions.

MOST IMPORTANT MESSAGES IN THIS YEAR’S WED ARE -

* WE MUST REDUCE OUR CONSUMPTION OF NON-RENEWABLE RESOURCES.

* WE MUST REDUCE THE GREENHOUSE GASES WE RELEASE.

* WASTE REDUCTION, REUSE, AND RECYCLING ALLOW US TO USE FEWER RAW MATERIALS, CONSERVE NATURAL RESOURCES, PRESERVING LANDFILL SPACE AND MINIMIZING ENERGY USE.

* GROW GREEN, GROW MORE TREES

May our Surround Always Remain … Healthy and Euphoric … May All the Trees … Bloom and flourish … Sending good wishes… For World Environment day – 5th June 2008 From: Partha Das Sharma http://www.environmentengineering.blogspot.com

Adoption of environment-friendly Green Technology in various fields is need-of-the-hour:

Adoption of environment-friendly Green Technology in various fields is need-of-the-hour:

Performance of green products is steadily improving, prices are going down, and tax breaks and subsidies are further helping erode financial barriers. The following list addresses environmental priorities in four broad consumer categories – (a) home, (b) car, (c) lifestyle, and the (d) future; identifying issues that consumers will face and ways they can help reduce the greenhouse gases they produce, minimize the depletion of natural resources, and produce and conserve energy more efficiently.

(a) Home –

1. Think solar panels. In many cases, solar can save you money in the long run. Solar panels also are getting more attractive.

2. Or think solar water. If you don't want to completely outfit your house with solar panels, you can deploy solar technology on an appliance-by-appliance basis.

3. Let the utility control your thermostat. These monitoring-and-control systems can indeed trim your use of peak power and lead to lower bills.

4. Move or remodel. If you're panning to buy a home, homes made from more eco-friendly materials should be given priority.

5. Switch to eco-friendly clothes and furniture.

6. Use green cleaning supplies. This is an important issue, but also one that's relatively easy to address.

(b) Car –

7. Buy a hybrid. Although the tax breaks on these cars can rise and fall, hybrids continue to get good reviews from customers, and the cars get quite a good fuel economy (about 60 miles a gallon).

8. Contemplate buying an electric car. Electric cars aren't perfect. Most barely can go more than 120 miles before needing a recharge and they cost more than their gas-powered equivalents, but advocates say both factors will improve.

9. Think diesel. Bio-diesel made from vegetable oil produces far less carbon dioxide than regular diesel. It can be put straight into conventional diesel cars.

(c) Lifestyle –

10. Swap the lightbulbs. Only about 5 percent of the energy that goes into incandescent lightbulbs turns into light. The rest turns into heat. Fluorescent-bulb manufacturers and light-emitting diode (LED) bulb makers say their products can produce as much light with far less energy.

11. Go organic in the garden. Traditional fertilizers and pesticides are made out of petroleum products and are being phased out by legislation due to concerns that they're causing health problems. Many companies have devised bio-pesticides, which kill fungi and other material with bacteria that's not harmful to humans.

12. Cut down on vampire-power gadgets. PCs, DVD players, televisions (especially some flat-panel models), and other devices can consume a lot of power, even in sleep mode, so unplug when you can.

13. Look for the green products and services such as dry cleaners or personal computer etc.

14. Buy carbon offsets. These arrangements are designed to allow individuals and organizations to reduce emissions directly or by participating in programs that, through various energy-conservation techniques and emissions-trading initiatives, attempt to achieve a net reduction in greenhouse gases.

(d) The future - Not everything will be easy when it comes to alternative energy. Here's a quick list of some other emerging technologies and issues that will likely become more prominent in the future.

15. Consider clean coal. Lung disease, mining accidents, environmental poisoning, these are just some of the associations mankind have with coal. Coal may never be as clean as solar power, but advocates point out the infrastructure already exists to adopt cleaner coal. In any event, phasing out coal will take years, so cleaner coal-burning technologies may as well be adopted.

16. Second and third thoughts on genetically modified (GM) crops. Corn, soy, sugar and other crops that now get converted to ethanol or bio-diesel have one thing in common: they were originally bred for food. To boost fuel production, these crops will likely need to be genetically enhanced.

17. Give up some open space for solar power and wind power. Providing solar power on a broad scale will require dedicating lots of land to power generation. Similarly, wind power often means placing large fields of turbines in the ocean.

18. Going for nuclear power generation in a big way. The nuclear issue is back on the table and will be one of many topics that governments of most of the nations will address when it comes to energy security.

19. Recycled water on tap. Water shortages will likely be the first major impact humans feel when it comes to global warming. China, Australia, and India already face significant challenges. To alleviate the problem, several countries are increasing investments in desalination technologies and purification systems for turning sewage water into drinking water.

20. High taxes. Developing green technologies and getting them into the market will require billions of dollars in grants, subsidies, and tax cuts that will often go to green-tech companies. Clean energy might require direct subsidies, but health care costs and the need for often-costly toxic-waste cleanups will decline.

Go Green and Save Green – Few suggestions:

Go Green and Save Green – Few suggestions:

To go green and save green is nothing but ways to live lightly on the Earth and at the same time, save money. Climate change is in the news. It seems like everyone is interested to think about going green. It is good news. As discussed earlier, many of the steps can be taken to stop climate change that can make our lives better. Younger generation would thank us for living more sustainable way. We should start making positive action now. Followings are few steps discussed:

1. Save energy to save money –

(a) Set your thermostat a few degrees lower in the winter and a few degrees higher in the summer to save on heating and cooling costs.

(b) Install compact fluorescent light bulbs (CFLs) when your older incandescent bulbs burn out.

(c) Unplug appliances when you're not using them. Or, use a "smart" power strip that senses when appliances are off and cuts unnecessary energy use.

(d) Wash clothes in cold water whenever possible. As much as 85 percent of the energy used to machine-wash clothes goes to heating the water.

(e) Use a drying rack or clothesline to save the energy otherwise used during machine drying.

2. Save water to save money –

(a) Take shorter showers to reduce water use. This will lower your water and heating bills too.

(b) Install a low-flow showerhead. They don't cost much, and the water and energy savings can quickly pay back your investment.

(c) Make sure you have a faucet aerator on each faucet. These inexpensive appliances conserve heat and water, while keeping water pressure high.

(d) Plant drought-tolerant native plants in your garden. Many plants need minimal watering. Find out which occur naturally in your area.

3. Less gas consumption is more money (and better health!) –

(a) Walk or bike to work. This saves on gas and parking costs while improving your cardiovascular health and reducing your risk of obesity.

(b) Consider telecommuting if you live far from your work. Or move closer. Even if this means paying more rent, it could save you money in the long term.

(c) Try to convince your local authority to create sidewalks and bike lanes. With little cost, these improvements can pay huge dividends in bettering your health and reducing traffic.

4. Eat smart –

(a) If you eat meat, add one meatless meal a week. Meat costs a lot at the store-and it's even more expensive when you consider the related environmental and health costs.

(b) Try to buy locally raised organic meat, eggs, and dairy whenever you can. Purchasing from local farmers keeps money in the local economy.

(c) Whatever your diet, eat low on the food chain. This is especially true for seafood.

5. Skip the bottled water –

(a) Use a water filter to purify tap water instead of buying bottled water. Not only is bottled water expensive, but it generates large amounts of container waste.

(b) Bring a reusable water bottle, preferably aluminum rather than plastic, with you when traveling or at work.

6. Think before you buy (better to buy reusable articles) –

(a) Go online to find new or gently used secondhand products as far as possible.

(b) Check out garage sales, thrift stores and consignment shops for clothing and other everyday items.

7. Borrow instead of buying –

(a) Borrow from libraries instead of buying personal books and movies. This saves money, not to mention the ink and paper that goes into printing new books.

(b) Share power tools and other appliances.

8. Buy smart –

(a) Buy in bulk. Purchasing food from bulk bins can save money and packaging.

(b) Wear clothes that don't need to be dry-cleaned. This saves money and cuts down on toxic chemical use.

(c) Invest in high-quality, long-lasting products. You might pay more now, but you'll be happy when you don't have to replace items as frequently (i.e., less waste generation).

9. Keep electronics out of the trash –

(a) Keep and use your cell phones, computers, and other electronics as long as possible.

(b) Donate or recycle them responsibly when the time comes. Electronic waste contains mercury and other toxics and is a growing environmental problem.

(c) Recycle your cell phone.

(d) Ask your local government to set up an electronics recycling and hazardous waste collection event.

10. Make your own cleaning supplies –

(a) Try to learn to make non-toxic cleaning products Tips are available in internet. Whenever you need them try to prepare for your own. All you need are a few simple ingredients like baking soda, vinegar, lemon, and soap.

(b) Making your own cleaning products saves money, time, and packaging etc. Your indoor air quality also improves.

11. Stay informed about going green –

(a) Lots of information in internet of environment journals is available regarding ways to go green. Try to follow them.

(b) Inform others on ways to go and keep green. Sharing information on environment issues with neighbors and colleagues are good habit in order promote saving our Earth from deterioration.

Environment-friendly organic food: Should we buy or bypass? – Discussion:

Environment-friendly organic food: Should we buy or bypass? – Discussion:

A. Many factors may influence your decision to buy — or not buy — organic food. Consider these factors:

(a) Nutrition. No conclusive evidence shows that organic food is more nutritious than is conventionally grown food. And the USDA — even though it certifies organic food — doesn't claim that these products are safer or more nutritious.

(b) Quality and appearance. Organic foods meet the same quality and safety standards as conventional foods. The difference lies in how the food is produced, processed and handled. You may find that organic fruits and vegetables spoil faster because they aren't treated with waxes or preservatives. Also, expect less-than-perfect appearances in some organic produce — odd shapes, varying colors and perhaps smaller sizes. In most cases, however, organic foods look identical to their conventional counterparts.

(c) Pesticides. Conventional growers use pesticides to protect their crops from molds, insects and diseases. When farmers spray pesticides, this can leave residue on produce. Some people buy organic food to limit their exposure to these residues. Most experts agree, however, that the amount of pesticides found on fruits and vegetables poses a very small health risk.

(d) Environment. Some people buy organic food for environmental reasons. Organic farming practices are designed to benefit the environment by reducing pollution and conserving water and soil.

(e) Cost. Most organic food costs more than conventional food products. Higher prices are due to more expensive farming practices, tighter government regulations and lower crop yields. Because organic farmers don't use herbicides or pesticides, many management tools that control weeds and pests is labor intensive. For example, organic growers may hand weed vegetables to control weeds, and you may end up paying more for these vegetables.

(f) Taste. Some people say they can taste the difference between organic and non-organic food. Others say they find no difference. Taste is a subjective and personal consideration, so decide for yourself. But whether you buy organic or not, finding the freshest foods available may have the biggest impact on taste.

B. Buying tips: Whether you're already a fan of organic foods or you just want to shop wisely and handle your food safely, consider these tips:

(a) Buy fruits and vegetables in season to ensure the highest quality. Also, try to buy your produce the day it's delivered to market to ensure that you're buying the freshest food possible. Ask your grocer what day new produce arrives.

(b) Read food labels carefully. Just because a product says it's organic or contains organic ingredients doesn't necessarily mean it's a healthier alternative. Some organic products may still be high in sugar, salt, fat or calories.

(c) Don't confuse natural foods with organic foods. Only those products with the "USDA Organic" label have met USDA standards.

(d) Wash all fresh fruits and vegetables thoroughly with running water to reduce the amount of dirt and bacteria. If appropriate, use a small scrub brush — for example, before eating apples, potatoes, cucumbers or other produce in which you eat the outer skin.

(e) If you're concerned about pesticides, peel your fruits and vegetables and trim outer leaves of leafy vegetables in addition to washing them thoroughly. Keep in mind that peeling your fruits and vegetables may also reduce the amount of nutrients and fiber. Some pesticide residue also collects in fat, so remove fat from meat and the skin from poultry and fish.