Minggu, 31 Januari 2016


COAL


Minggu, 06 Desember 2015


Selasa, 20 Oktober 2015


PT. BANGUN ENERGI


Rabu, 14 Oktober 2015

TOTAL MOISTURE CAUSE CHANGE

TOTAL MOISTURE CAUSE CHANGE
In this case we discussed for coal moisture at the time dipertambangan.
The existence of adherent moisture in coal might happen in some situations, among others:

     Groundwater mixing with coal mining time and on the conditions of origin in the ground.
     A sprinkling of rain water on a pile of coal
     the remnants of the water that remains on the surface of the coal after the washing process.
     Water is sprayed to reduce dust in the coal pile.

Senin, 28 September 2015

BANPU

Registered and Company Office

Centennial Coal Company Limited
Level 18, BT Tower
1 Market Street
Sydney NSW 2000 Australia
Tel: (61-2) 9266 2700
Fax: (61-2) 9261 5533

Regional Offices

Fassifern Office
Tel: (61-2) 4935 8960
Lidsdale House - Lithgow Office
Tel: (61-2) 6355 9818
Please see below for Mine Site contact details

Enquiries

Human Resource enquiries
Tel: (61-2) 4935 8960
email: hr@centennialcoal.com.au
Coal enquiries
email: sales@centennialcoal.com.au
General enquiries
email: info@centennialcoal.com.au

Centennial Mines

Airly (including Airly Extension Project)
Tel: (61-2) 6359 2121
Airly community information and complaints*: (61-2) 6359 2100
Email: info.airly@centennialcoal.com.au
For more information on Airly's operations please click here.
Angus Place (including Angus Place Extension Project) 
Tel: (61-2) 6354 8700
Angus Place community information and complaints*: (61-2) 6354 8700
Email: angusplacecolliery@centennialcoal.com.au
For more information on Angus Place's operations please click here.
Awaba
Awaba community information and complaints*: 1800 247 662
Email: awabacolliery@centennialcoal.com.au
For more information on Awaba's operations please click here.
Charbon 
Tel: (61-2) 6379 4255
Charbon community information and complaints*: (61-2) 6357 9206
Email: charboncolliery@centennialcoal.com.au
For more information on Charbon's operations please click here.
Clarence
Tel: (61-2) 6353 8000
Clarence community information and complaints*: (61-2) 6353 8039
Email: clarencecolliery@centennialcoal.com.au
For more information on Clarence's operations please click here.
Ivanhoe
Ivanhoe Number 2 and Ivanhoe North community information and complaints*: 1800 609 822
Email: ivanhoecolliery@centennialcoal.com.au
For more information on Ivanhoe North's operations please click here.

Lamberts Gully
Lamberts Gully community information and complaints*: (61-2) 6355 9500
Email: lambertsgullymine@centennialcoal.com.au
For more information on Lamberts Gully please click here.
Mandalong
Tel: (61-2) 4973 0900
Mandalong community information and complaints*: 1800 730 919
Email: mandalongmine@centennialcoal.com.au
For more information on Mandalong's operations please click here.
Mannering
Tel: (61-2) 4358 0580
Mannering community information and complaints*: (61-2) 4358 0580
Email: manneringcolliery@centennialcoal.com.au
For more information on Mannering's operations please click here.
Myuna
Tel: (61-2) 4970 0270
Myuna community information and complaints*: (61-2) 4970 0270
Email: myunacolliery@centennialcoal.com.au
For more information on Myuna's operations please click here.
Newstan (including Newstan Extension and Northern Coal Services Logistics projects)
Tel: (61-2) 4956 0200
Newstan community information and complaints*: 1800 247 662
Email: newstancolliery@centennialcoal.com.au
For more information on Newstan's operations please click here.
Springvale (including Springvale Extension Project)
Tel: (61-2) 6350 1600
Springvale community information and complaints*: (61-2) 6350 1640
Email: springvalecolliery@centennialcoal.com.au
For more information on Springvale's operations please click here.

Projects

Inglenook
Contact the Environment and Community Coordinator, and Project Manager:
Email: inglenook@centennialcoal.com.au
Community information and complaints*: 1800 617 173
For more information on the Inglenook Exploration Project operations please click here.
Lidsdale Siding
Contact the Environment and Community Coordinator:
Community information and complaints*: 1800 460 922
For more information on Lidsdale Siding's operations please click here.
Mandalong Southern Extension
Contact the Environmental Coordinator and Project Manager:
Email: mandalongsouthproject@centennialcoal.com.au
Community information and complaints*: 1800 731 966
For more information on the Mandalong Southern Extension Project operations please click here.
Neubeck 
Contact the Environmental Coordinator and Project Manager:
Email: neubeck@centennialcoal.com.au
Community information and complaints*: 1800 770 205
For more information on the Neubeck Project operations please click here.
* Please note that our mine sites are obliged to offer a 'complaints line' as a requirement of their Environment Protection Licences. We operate our mines to minimise adverse community impact, however, we do welcome any general enquiries and make a commitment to respond efficiently and effectively.

GOV. COAL UK

Customer services, mining reports and records

200 Lichfield Lane


Mansfield
Nottinghamshire
NG18 4RG

Report a coal mine hazard

The Coal Authority
200 Lichfield Lane
Mansfield
Nottinghamshire
NG18 4RG
24-hour number for reporting public safety hazards and incidents associated with coal mining.

Press office

John Delaney or Joanne Wilson
200 Lichfield Lane
Mansfield
Nottinghamshire
NG18 4RG


Minggu, 27 September 2015

A range of advanced coal combustion technologies have been developed to improve the efficiency of coal-fired power generation. New, more efficient coal-fired combustion technologies reduce emissions of CO2, as well as pollutants such as NOx, SOx and particulates.


Improving efficiency levels increases the amount of energy that can be extracted from a single unit of coal. Increases in the efficiency of electricity generation are essential in tackling climate change. A one percentage point improvement in the efficiency of a conventional pulverised coal combustion plant results in a 2-3% reduction in CO2 emissions.
Moving the current average global efficiency rate of coal-fired power plants from 33% to 40% by deploying more advanced off-the-shelf technology could cut two gigatonnes of CO2 emissions now, while allowing affordable energy for economic development and poverty reduction.
Two gigatonnes of CO2 is equivalent to:
  • India's annual CO2 emissions
  • Running the European Union's Emissions Trading Scheme for 53 years at its current rate, or
  • Running the Kyoto Protocol three times over.
Deploying high efficiency, low emission (HELE) coal-fired power plants is a key first step along a pathway to near-zero emissions from coal with carbon capture, use and storage (CCUS).

Platform for Accelerating Coal Efficiency (PACE)

Given the huge potential offered by improving efficiencies, the World Coal Association has published a concept paper on the launch of a global Platform for Accelerating Coal Efficiency (PACE).
The vision of PACE would be that for countries choosing to use coal, the most efficient power plant technology possible is deployed. The overriding objective would be to raise the global average efficiency of coal-fired power plants and so minimise CO2 emissions which will otherwise be emitted while maintaining legitimate economic development and poverty alleviation efforts.

Technologies

Improvements in the efficiency of coal-fired power plants can be achieved with technologies including:
  • Fluidised Bed Combustion
  • Supercritical & Ultrasupercritical Boilers
  • Integrated Gasification Combined Cycle

Fluidised Bed Combustion

Fluidised Bed Combustion (FBC) is a very flexible method of electricity production – most combustible material can be burnt including coal, biomass and general waste. FBC systems improve the environmental impact of coal-based electricity, reducing SOx and NOx emissions by 90%.
In fluidised bed combustion, coal is burned in a reactor comprised of a bed through which gas is fed to keep the fuel in a turbulent state. This improves combustion, heat transfer and recovery of waste products. The higher heat exchanger efficiencies and better mixing of FBC systems allows them to operate at lower temperatures than conventional pulverised coal combustion (PCC) systems. By elevating pressures within a bed, a high-pressure gas stream can be used to drive a gas turbine, generating electricity.
FBC systems fit into two groups, non-pressurised systems (FBC) and pressurised systems (PFBC), and two subgroups, circulating or bubbling fluidised bed.
  • Non-pressurised FBC systems operate at atmospheric pressure and are the most widely applied type of FBC. They have efficiencies similar to PCC – 30-40%
  • Pressurised FBC systems operate at elevated pressures and produce a high-pressure gas stream that can drive a gas turbine, creating a more efficient combined cycle system – over 40%
  • Bubbling uses a low fluidising velocity – so that the particles are held mainly in a bed – and is generally used with small plants offering a non-pressurised efficiency of around 30%
  • Circulating uses a higher fluidising velocity – so the particles are constantly held in the flue gases – and are used for much larger plant offering efficiency of over 40%
The flexibility of FBC systems allows them to utilise abandoned coal waste that previously would not be used due to its poor quality.

Supercritical & Ultrasupercritical Technology

New pulverised coal combustion systems – utilising supercritical and ultra-supercritical technology – operate at increasingly higher temperatures and pressures and therefore achieve higher efficiencies than conventional PCC units and significant CO2 reductions.
Supercritical steam cycle technology has been used for decades and is becoming the system of choice for new commercial coal-fired plants in many countries.
Research and development is under way for ultra-supercritical units operating at even higher efficiencies, potentially up to around 50%. The introduction of ultra-supercritical technology has been driven over recent years in countries such as Denmark, Germany and Japan, in order to achieve improved plant efficiencies and reduce fuel costs. Research is focusing on the development of new steels for boiler tubes and on high alloy steels that minimise corrosion.
These developments are expected to result in a dramatic increase in the number of SC plants and USC units installed over coming years.

Integrated Gasification Combined Cycle (IGCC)

An alternative to achieving efficiency improvements in conventional pulverised coal-fired power stations is through the use of gasification technology. IGCC plants use a gasifier to convert coal (or other carbon-based materials) to syngas, which drives a combined cycle turbine.
Coal is combined with oxygen and steam in the gasifier to produce the syngas, which is mainly H2 and carbon monoxide (CO). The gas is then cleaned to remove impurities, such as sulphur, and the syngas is used in a gas turbine to produce electricity. Waste heat from the gas turbine is recovered to create steam which drives a steam turbine, producing more electricity – hence a combined cycle system.
By adding a ‘shift’ reaction, additional hydrogen can be produced and the CO can be converted to CO2 which can then be captured and stored. IGCC efficiencies typically reach the mid-40s, although plant designs offering around 50% efficiencies are achievable.
Reliability and availability have been challenges facing IGCC development and commercialisation. Cost has also been an issue for the wider uptake of IGCC as they have been significantly more expensive than conventional coal-fired plant.
Gasification may also be one of the best ways to produce clean-burning hydrogen for tomorrow’s cars and power-generating fuel cells. Hydrogen and other coal gases can be used to fuel power-generating turbines, or as the chemical building blocks for a wide range of commercial products, including diesel and other transport fuels.

The deployment of all energy generating technologies invariably leads to some degree of environmental impact.


The nature of the impact is dependent on the specific generation technology used and may include:
  • concerns over land and water resource use
  • pollutant emissions
  • waste generation
  • public health and safety concerns
The use of coal for power generation is not exempt from these impacts and has been associated with a number of environmental challenges, primarily associated with air emissions. Coal has demonstrated the ability to meet such challenges in the past and the expectation is that it will successfully meet future environmental challenges.
Viable, highly effective technologies have been developed to tackle environmental challenges, including the release of pollutants – such as oxides of sulphur (SOx) and nitrogen (NOx) – and particulate and trace elements, such as mercury. More recently, the focus has been on developing and deploying technologies to tackle greenhouse gas emissions associated with the use of coal, including carbon dioxide (CO2) and methane (CH4).

Reducing Pollution

Technologies are now available to improve the environmental performance of coal-fired power stations for a range of pollutants. In many cases a number of technologies are available to mitigate any given environmental impact. Which technology option is selected for a power plant will vary depending on its specific characteristics such as location, age, and fuel source. The maturity of environmental technologies varies substantially, with some being widely deployed and available ‘off the shelf’ to new innovative technologies which are still in the demonstration phase.
A key strategy in the mitigation of coal’s environmental impacts is to improve the energy efficiency of power plants. Efficient plants burn less coal per unit of energy produced and consequently have lower associated environmental impacts. Efficiency improvements, particularly those related to combustion technologies, are an active area of research and an important component of a climate change mitigation strategy (see page on efficiency improvements).

Coal Washing

Mined coal is of variable quality and is frequently associated with mineral and chemical material including clay, sand, sulphur and trace elements. Coal cleaning by washing and beneficiation removes this associated material, prepares the coal to customer specifications and is an important step in reducing emissions from coal use.
Coal cleaning reduces the ash content of coal by over 50% resulting in less waste, lower sulphur dioxide (SO2) emissions and improved thermal efficiencies, leading to lower CO2 emissions. While coal preparation is standard practice in many countries, greater uptake in developing countries is needed as a low-cost way to improve the environmental performance of coal.

Particulates

Particulate emissions are finely divided solid and liquid (other than water) substances that are emitted from power stations. Particulates can affect people’s respiratory systems, impact local visibility and cause dust problems. A number of technologies have been developed to control particulate emissions and are widely deployed in both developed and developing countries, including:
  • electrostatic precipitators
  • fabric filters or baghouses
  • wet particulate scrubbers
  • hot gas filtration systems.
Electrostatic precipitators (ESP) are the most widely used particulate control technology and use an electrical field to create a charge on particles in the flue gas in order to attract them to collecting plates.
Fabric filters collect particulates from the flue gas as it passes through the tightly woven fabric of the bag. Both ESP and fabric filters are highly efficient, removing over 99.95% of particulate emissions.
Wet scrubbers are used to capture both particulates and SO2 by injecting water droplets into the flue gas to form a wet by-product. The addition of lime to the water helps to increase SO2 removal.
Hot gas filtration systems operate at higher temperatures (260-900ºC) and pressures (1-3 MPa) than conventional particulate removal technologies, eliminating the need for cooling of the gas, making them suitable for modern combined-cycle power plants such as Integrated Gasification Combined Cycle (IGCC). A range of hot gas filtration technologies have been under development for a number of years but further research is needed to enable widespread commercial deployment.

Acid Rain

During the late 20th century, rising global concerns over the effects of acid rain led to the development and utilisation of technologies to reduce emissions of SO2 and nitrogen oxides. The formation of SO2 occurs during the combustion of coals containing sulphur and can lead to acid rain and acidic aerosols (extremely fine air-borne particles). A number of technologies, collectively known as flue gas desulphurisation (FGD), have been developed to reduce SO2 emissions. These typically use a chemical sorbent, usually lime or limestone, to remove SO2 from the flue gas. FGD technologies have been installed in many countries and have led to enormous reductions in emissions.
The combustion of coal in the presence of nitrogen, from either the fuel or air, leads to the formation of nitrogen oxides. The release of NOx to the atmosphere can contribute to smog, ground level ozone, acid rain and GHG emissions. Technologies to reduce NOx emissions are referred to as either primary abatement and control methods or as flue gas treatment.
Primary measures include the use of low NOx burners and burner optimisation techniques to minimise the formation of NOx during combustion. These primary control measures are routinely included in newly built power stations and may also be retrofitted when reductions in NOx emissions are required. Alternatively technologies such as Selective Catalytic Reduction (SCR) and Selective Non-Catalytic Reduction (SNCR) lower NOx emissions by treating the NOx post-combustion in the flue gas. SCR technology has been used commercially for almost 30 years and is now deployed throughout the world, removing between 80-90% of NOx emissions at a given plant.
Research is under way to develop combined SO2/NOx removal technologies. Such technologies are technically challenging and expensive but new advances hold the promise of overcoming these issues.

Trace Elements

Coal is a chemically complex substance, naturally containing many trace elements including mercury, selenium and arsenic. The combustion of coal can result in trace elements being released from power stations with potentially harmful impacts to both human health and the environment. A number of technologies are used to limit the release of trace elements including coal washing, particulate control devices, fluidised bed combustion, activated carbon injection and FGDs. The choice of mitigation technology will be dependent on the trace elements present and local air quality standard objectives. Research is ongoing to develop better sorbents and reagents that will improve the performance of FGD with respect to trace element removal.

Waste

The combustion of coal generates waste consisting primarily of non-combustible mineral matter along with a small amount of unreacted carbon. The production of this waste can be minimised by coal cleaning prior to combustion. This represents a cost-effective method of providing high quality coal, while helping to reduce power station waste and increasing efficiencies. Waste can be further minimised through the use of high efficiency coal combustion technologies.
There is increasing awareness of the opportunities to reprocess power station waste into valuable materials for use primarily in the construction and civil engineering industry. A wide variety of uses have been developed for coal waste including boiler slag for road surfacing, fluidised bed combustion waste as an agricultural lime and the addition of fly ash to cement (see page on coal combustion

Carbon Capture & Storage Technologies


Addressing the challenge of climate change, while meeting the need for affordable energy, will require access to and deployment of the full range of energy efficient and low carbon technologies.

Addressing the challenge of climate change, while meeting the need for affordable energy, will require access to and deployment of the full range of energy efficient and low carbon technologies. Capturing carbon dioxide that would otherwise be emitted to the atmosphere and injecting it to be stored in deep geological formations (CCS) is the only technology currently available to make deep cuts in greenhouse gas emissions from fossil fuel use while allowing energy needs to be met securely and affordably.
CCS is not a replacement for taking actions which increase energy efficiency or maximising the use of renewables or other less carbon-intensive forms of energy. A portfolio approach taking every opportunity to reduce emissions will be required to meet the challenge of climate change.

Is CCS a proven technology?

All the elements of CCS have been separately proven and deployed in various fields of commercial activity. In fact, around 1 million tonnes of CO2 has been stored each year at the Sleipner project since it started operating in 1996.
Failure to deploy CCS will seriously hamper international efforts to address climate change. The Intergovernmental Panel on Climate Change (IPCC) (link opens PDF of IPCC 2005 Special Report on CCS) has identified CCS as a critical technology to stabilise atmospheric greenhouse gas concentrations in an economically efficient manner. The IPCC has concluded that by 2100, CCS could contribute up to 55% of the cumulative mitigation effort whilst reducing the costs of stabilisation to society by 30% or more.

How is CO2 Captured?

While CO2 capture technologies are new to the power industry, they have been deployed for the past sixty years by the oil, gas and chemical industries. They are an integral component of natural gas processing and of many coal gasification processes used for the production of syngas, chemicals and liquid fuels. There are three main CO2 capture processes for power generation.
  • post-combustion
  • pre-combustion
  • oxyfuel
‘Post-combustion’ capture involves separating the CO2 from other exhaust gases after combustion of the fossil fuel. Post-combustion capture systems are similar to those that already remove pollutants such as particulates, sulphur oxides and nitrogen oxides from many power plants.
The most commonly used process for post-combustion CO2 capture is made possible through special chemicals called amines. A CO2 rich gas stream, such as a power plant’s flue gas, is “bubbled” through an amine solution. The CO2 bonds with the amines as it passes through the solution while other gases continue up through the flue. The CO2 in the resulting CO2-saturated amine solution is then removed from the amines, “captured” and is ready for carbon storage. The amines themselves can be recycled and re-used.
Whilst post-combustion CO2 capture is technically available now for coal-based power plants, it has not yet been used commercially for large-scale CO2 removal.
‘Pre-combustion' capture involves separating CO2 before the fuel is burned. Solid or liquid fuels such as coal, biomass or petroleum products are first gasified in a chemical reaction at very high temperatures with a controlled amount of oxygen. Gasification produces two gases, hydrogen and carbon monoxide (CO). The CO is converted to CO2 and removed, leaving pure hydrogen to be burned to produce electricity or used for another purpose. The CO2 is then compressed into a supercritical fluid for transport and geological storage. The hydrogen can be used to generate power in an advanced gas turbine and steam cycle or in fuels cells – or a combination of both.
Oxyfuel combustion (also called oxyfiring) involves the combustion of coal in pure oxygen, rather than air, to fuel a conventional steam generator. By avoiding the introduction of nitrogen into the combustion chamber, the amount of CO2 in the power station exhaust stream is greatly concentrated, making it easier to capture and compress. Oxyfuel combustion with CO2 storage is currently at the demonstration phase.
Each of these capture options has its particular benefits. Post-combustion capture and oxyfuel have the potential to be retrofitted to existing coal-fired power stations and new plants constructed over the next 10-20 years. Pre-combustion capture utilising IGCC is potentially more flexible, opening up a wider range of possibilities for coal, including a major role in a future hydrogen economy.
All the options for capturing CO2 from power generation have higher capital and operating costs as well as lower efficiencies then conventional power plants without capture. Capture is typically the most expensive part of the CCS chain. Costs are higher than for plants without CCS because more equipment must be built and operated. Around 10-40% more energy is required with CCS than without [IEA GHG]. Energy is required mostly to separate the CO2 from other gases and to compress it, but some is also used to transport the CO2 to the injection site and inject it underground.
As CCS and power generation technology become more efficient and better integrated, the increased energy use is likely to fall significantly below early levels. Much of the work on capture is focused on lowering costs and improving efficiency as well as improving the integration of the capture and power generation components. These improvements will reduce energy requirements.

Transportation

The technology for CO2 transportation and its environmental safety are well-established. CO2 is largely inert and easily handled and is already transported in high pressure pipelines.In the USA, CO2 is already transported by pipeline for use in Enhanced Oil Recovery (EOR).
The means of transport depends on the quantity of CO2 to be transported, the terrain and the distance between the capture plant and storage site. In general, pipelines are used for large volumes over shorter distances. In some situations or locations, transport of CO2 by ship may be more economic, particularly when the CO2 has to be moved over large distances or overseas.

Carbon Capture Use & Storage


Carbon capture use and geological storage (CCUS) technology is the only currently available technology that allows very deep cuts to be made in CO2 emissions to atmosphere from fossil fuels at the scale needed.

Failure to widely deploy CCUS will seriously hamper international efforts to address climate change. The Intergovernmental Panel on Climate Change (IPCC) - the pre-eminent body on climate science - has identified CCUS as a critical technology to stabilise atmospheric greenhouse gas concentrations in an economically efficient manner. The IPCC found that CCUS could contribute up to 55% of the cumulative mitigation effort by 2100 while reducing the costs of stabilisation to society by 30% or more.
CCUS will be needed across a number of sectors that need to tackle CO2 emissions, including fossil fuel power stations (coal, gas and oil), steel, aluminium, cement and chemicals.

Coal Mining & the Environment


Coal mining, particularly surface mining, requires large areas of land to be temporarily disturbed. This raises a number of environmental challenges, including soil erosion, dust, noise and water pollution, and impacts on local biodiversity. Steps are taken in modern mining operations to minimise impacts on all aspects of the environment. By carefully pre-planning projects, implementing pollution control measures, monitoring the effects of mining and rehabilitating mined areas, the coal industry minimises the impact of its activities on the neighbouring community, the immediate environment and on long-term land capability.

Land Disturbance

In best practice, studies of the immediate environment are carried out several years before a coal mine opens in order to define the existing conditions and to identify potential problems. The studies look at the impact of mining on surface and ground water, soils, local land use, native vegetation and wildlife populations. Computer simulations can be undertaken to model impacts on the local environment. The findings are then reviewed as part of the process leading to the award of a mining permit by the relevant government authorities.

Mine Subsidence

Mine subsidence can be a problem with underground coal mining, whereby the ground level lowers as a result of coal having been mined beneath. A thorough understanding of subsistence patterns in a particular region allows the effects of underground mining on the surface to be quantified. The coal mining industry uses a range of engineering techniques to design the layout and dimensions of its underground mine workings so that surface subsidence can be anticipated and controlled. This ensures the safe, maximum recovery of a coal resource, while providing protection to other land uses.

Water Pollution

Mine operations work to improve their water management, aiming to reduce demand through efficiency, technology and the use of lower quality and recycled water. Water pollution is controlled by carefully separating the water runoff from undisturbed areas from water which contains sediments or salt from mine workings. Clean runoff can be discharged into surrounding water courses, while other water is treated and can be reused such as for dust suppression and in coal preparation plants.
Acid mine drainage
Acid mine drainage (AMD) can be a challenge at coal mining operations. AMD is metal-rich water formed from the chemical reaction between water and rocks containing sulphur-bearing minerals. The runoff formed is usually acidic and frequently comes from areas where ore- or coal mining activities have exposed rocks containing pyrite, a sulphur-bearing mineral. However, metal-rich drainage can also occur in mineralised areas that have not been mined. AMD is formed when the pyrite reacts with air and water to form sulphuric acid and dissolved iron. This acid run-off dissolves heavy metals such as copper, lead and mercury into ground and surface water.
There are mine management methods that can minimise the problem of AMD, and effective mine design can keep water away from acid generating materials and help prevent AMD occurring. AMD can be treated actively or passively.
  • Active treatment involves installing a water treatment plant, where the AMD is first dosed with lime to neutralise the acid and then passed through settling tanks to remove the sediment and particulate metals.
  • Passive treatment aims to develop a self-operating system that can treat the effluent without constant human intervention.
Recycling waste water from mines into clean drinking water
Photo: PT Adaro Indonesia

Dust & Noise Pollution

Dust at mining operations can be caused by trucks being driven on unsealed roads, coal crushing operations, drilling operations and wind blowing over areas disturbed by mining.
Dust levels can be controlled by spraying water on roads, stockpiles and conveyors. Other steps can also be taken, including fitting drills with dust collection systems and purchasing additional land surrounding the mine to act as a buffer zone. Trees planted in these buffer zones can also minimise the visual impact of mining operations on local communities.
Noise can be controlled through the careful selection of equipment and insulation and sound enclosures around machinery.

Rehabilitation

Coal mining is only a temporary use of land, so it is vital that rehabilitation of land takes place once mining operations have stopped. In best practice a detailed rehabilitation or reclamation plan is designed and approved for each coal mine, covering the period from the start of operations until well after mining has finished.
Where the mining is underground, the surface area can be simultaneously used for other uses - such as forests, cattle grazing and growing crops - with little of no disruption to the existing land use.
Mine reclamation activities are undertaken gradually – with the shaping and contouring of spoil piles, replacement of topsoil, seeding with grasses and planting of trees taking place on the mined-out areas. Care is taken to relocate streams, wildlife, and other valuable resources.
As mining operations cease in one section of a surface mine, bulldozers and scrapers are used to reshape the disturbed area. Drainage within and off the site is carefully designed to make the new land surface as stable and resistant to soil erosion as the local environment allows. Based on the soil requirements, the land is suitably fertilised and revegetated. Reclaimed land can have many uses, including agriculture, forestry, wildlife habitation and recreation.
Companies carefully monitor the progress of rehabilitation and usually prohibit the use of the land until the vegetation is self-supporting. The cost of the rehabilitation of the mined land is factored into the mine’s operating costs.

Using Methane from Coal Mines

Methane (CH4) is a gas formed as part of the process of coal formation. It is released from the coal seam and the surrounding disturbed strata during mining operations. Methane is a potent greenhouse gas, with a global warming potential 23 times that of carbon dioxide. While coal is not the only source of methane emissions – agricultural activities are major emitters – methane from coal seams can be utilised rather than released to the atmosphere with a significant environmental benefit (see methane section of website).

Improving Efficiencies


A range of advanced coal combustion technologies have been developed to improve the efficiency of coal-fired power generation. New, more efficient coal-fired combustion technologies reduce emissions of CO2, as well as pollutants such as NOx, SOx and particulates.

Improving efficiency levels increases the amount of energy that can be extracted from a single unit of coal. Increases in the efficiency of electricity generation are essential in tackling climate change. A one percentage point improvement in the efficiency of a conventional pulverised coal combustion plant results in a 2-3% reduction in CO2 emissions.
Moving the current average global efficiency rate of coal-fired power plants from 33% to 40% by deploying more advanced off-the-shelf technology could cut two gigatonnes of CO2 emissions now, while allowing affordable energy for economic development and poverty reduction.
Two gigatonnes of CO2 is equivalent to:
  • India's annual CO2 emissions
  • Running the European Union's Emissions Trading Scheme for 53 years at its current rate, or
  • Running the Kyoto Protocol three times over.
Deploying high efficiency, low emission (HELE) coal-fired power plants is a key first step along a pathway to near-zero emissions from coal with carbon capture, use and storage (CCUS).

Platform for Accelerating Coal Efficiency (PACE)

Given the huge potential offered by improving efficiencies, the World Coal Association has published a concept paper on the launch of a global Platform for Accelerating Coal Efficiency (PACE).
The vision of PACE would be that for countries choosing to use coal, the most efficient power plant technology possible is deployed. The overriding objective would be to raise the global average efficiency of coal-fired power plants and so minimise CO2 emissions which will otherwise be emitted while maintaining legitimate economic development and poverty alleviation efforts.

Technologies

Improvements in the efficiency of coal-fired power plants can be achieved with technologies including:
  • Fluidised Bed Combustion
  • Supercritical & Ultrasupercritical Boilers
  • Integrated Gasification Combined Cycle

Fluidised Bed Combustion

Fluidised Bed Combustion (FBC) is a very flexible method of electricity production – most combustible material can be burnt including coal, biomass and general waste. FBC systems improve the environmental impact of coal-based electricity, reducing SOx and NOx emissions by 90%.
In fluidised bed combustion, coal is burned in a reactor comprised of a bed through which gas is fed to keep the fuel in a turbulent state. This improves combustion, heat transfer and recovery of waste products. The higher heat exchanger efficiencies and better mixing of FBC systems allows them to operate at lower temperatures than conventional pulverised coal combustion (PCC) systems. By elevating pressures within a bed, a high-pressure gas stream can be used to drive a gas turbine, generating electricity.
FBC systems fit into two groups, non-pressurised systems (FBC) and pressurised systems (PFBC), and two subgroups, circulating or bubbling fluidised bed.
  • Non-pressurised FBC systems operate at atmospheric pressure and are the most widely applied type of FBC. They have efficiencies similar to PCC – 30-40%
  • Pressurised FBC systems operate at elevated pressures and produce a high-pressure gas stream that can drive a gas turbine, creating a more efficient combined cycle system – over 40%
  • Bubbling uses a low fluidising velocity – so that the particles are held mainly in a bed – and is generally used with small plants offering a non-pressurised efficiency of around 30%
  • Circulating uses a higher fluidising velocity – so the particles are constantly held in the flue gases – and are used for much larger plant offering efficiency of over 40%
The flexibility of FBC systems allows them to utilise abandoned coal waste that previously would not be used due to its poor quality.

Supercritical & Ultrasupercritical Technology

New pulverised coal combustion systems – utilising supercritical and ultra-supercritical technology – operate at increasingly higher temperatures and pressures and therefore achieve higher efficiencies than conventional PCC units and significant CO2 reductions.
Supercritical steam cycle technology has been used for decades and is becoming the system of choice for new commercial coal-fired plants in many countries.
Research and development is under way for ultra-supercritical units operating at even higher efficiencies, potentially up to around 50%. The introduction of ultra-supercritical technology has been driven over recent years in countries such as Denmark, Germany and Japan, in order to achieve improved plant efficiencies and reduce fuel costs. Research is focusing on the development of new steels for boiler tubes and on high alloy steels that minimise corrosion.
These developments are expected to result in a dramatic increase in the number of SC plants and USC units installed over coming years.

Integrated Gasification Combined Cycle (IGCC)

An alternative to achieving efficiency improvements in conventional pulverised coal-fired power stations is through the use of gasification technology. IGCC plants use a gasifier to convert coal (or other carbon-based materials) to syngas, which drives a combined cycle turbine.
Coal is combined with oxygen and steam in the gasifier to produce the syngas, which is mainly H2 and carbon monoxide (CO). The gas is then cleaned to remove impurities, such as sulphur, and the syngas is used in a gas turbine to produce electricity. Waste heat from the gas turbine is recovered to create steam which drives a steam turbine, producing more electricity – hence a combined cycle system.
By adding a ‘shift’ reaction, additional hydrogen can be produced and the CO can be converted to CO2 which can then be captured and stored. IGCC efficiencies typically reach the mid-40s, although plant designs offering around 50% efficiencies are achievable.
Reliability and availability have been challenges facing IGCC development and commercialisation. Cost has also been an issue for the wider uptake of IGCC as they have been significantly more expensive than conventional coal-fired plant.
Gasification may also be one of the best ways to produce clean-burning hydrogen for tomorrow’s cars and power-generating fuel cells. Hydrogen and other coal gases can be used to fuel power-generating turbines, or as the chemical building blocks for a wide range of commercial products, including diesel and other transport fuels.

Coal Use & the Environment


The deployment of all energy generating technologies invariably leads to some degree of environmental impact.

The nature of the impact is dependent on the specific generation technology used and may include:
  • concerns over land and water resource use
  • pollutant emissions
  • waste generation
  • public health and safety concerns
The use of coal for power generation is not exempt from these impacts and has been associated with a number of environmental challenges, primarily associated with air emissions. Coal has demonstrated the ability to meet such challenges in the past and the expectation is that it will successfully meet future environmental challenges.
Viable, highly effective technologies have been developed to tackle environmental challenges, including the release of pollutants – such as oxides of sulphur (SOx) and nitrogen (NOx) – and particulate and trace elements, such as mercury. More recently, the focus has been on developing and deploying technologies to tackle greenhouse gas emissions associated with the use of coal, including carbon dioxide (CO2) and methane (CH4).

Reducing Pollution

Technologies are now available to improve the environmental performance of coal-fired power stations for a range of pollutants. In many cases a number of technologies are available to mitigate any given environmental impact. Which technology option is selected for a power plant will vary depending on its specific characteristics such as location, age, and fuel source. The maturity of environmental technologies varies substantially, with some being widely deployed and available ‘off the shelf’ to new innovative technologies which are still in the demonstration phase.
A key strategy in the mitigation of coal’s environmental impacts is to improve the energy efficiency of power plants. Efficient plants burn less coal per unit of energy produced and consequently have lower associated environmental impacts. Efficiency improvements, particularly those related to combustion technologies, are an active area of research and an important component of a climate change mitigation strategy (see page on efficiency improvements).

Coal Washing

Mined coal is of variable quality and is frequently associated with mineral and chemical material including clay, sand, sulphur and trace elements. Coal cleaning by washing and beneficiation removes this associated material, prepares the coal to customer specifications and is an important step in reducing emissions from coal use.
Coal cleaning reduces the ash content of coal by over 50% resulting in less waste, lower sulphur dioxide (SO2) emissions and improved thermal efficiencies, leading to lower CO2 emissions. While coal preparation is standard practice in many countries, greater uptake in developing countries is needed as a low-cost way to improve the environmental performance of coal.

Particulates

Particulate emissions are finely divided solid and liquid (other than water) substances that are emitted from power stations. Particulates can affect people’s respiratory systems, impact local visibility and cause dust problems. A number of technologies have been developed to control particulate emissions and are widely deployed in both developed and developing countries, including:
  • electrostatic precipitators
  • fabric filters or baghouses
  • wet particulate scrubbers
  • hot gas filtration systems.
Electrostatic precipitators (ESP) are the most widely used particulate control technology and use an electrical field to create a charge on particles in the flue gas in order to attract them to collecting plates.
Fabric filters collect particulates from the flue gas as it passes through the tightly woven fabric of the bag. Both ESP and fabric filters are highly efficient, removing over 99.95% of particulate emissions.
Wet scrubbers are used to capture both particulates and SO2 by injecting water droplets into the flue gas to form a wet by-product. The addition of lime to the water helps to increase SO2 removal.
Hot gas filtration systems operate at higher temperatures (260-900ºC) and pressures (1-3 MPa) than conventional particulate removal technologies, eliminating the need for cooling of the gas, making them suitable for modern combined-cycle power plants such as Integrated Gasification Combined Cycle (IGCC). A range of hot gas filtration technologies have been under development for a number of years but further research is needed to enable widespread commercial deployment.

Acid Rain

During the late 20th century, rising global concerns over the effects of acid rain led to the development and utilisation of technologies to reduce emissions of SO2 and nitrogen oxides. The formation of SO2 occurs during the combustion of coals containing sulphur and can lead to acid rain and acidic aerosols (extremely fine air-borne particles). A number of technologies, collectively known as flue gas desulphurisation (FGD), have been developed to reduce SO2 emissions. These typically use a chemical sorbent, usually lime or limestone, to remove SO2 from the flue gas. FGD technologies have been installed in many countries and have led to enormous reductions in emissions.
The combustion of coal in the presence of nitrogen, from either the fuel or air, leads to the formation of nitrogen oxides. The release of NOx to the atmosphere can contribute to smog, ground level ozone, acid rain and GHG emissions. Technologies to reduce NOx emissions are referred to as either primary abatement and control methods or as flue gas treatment.
Primary measures include the use of low NOx burners and burner optimisation techniques to minimise the formation of NOx during combustion. These primary control measures are routinely included in newly built power stations and may also be retrofitted when reductions in NOx emissions are required. Alternatively technologies such as Selective Catalytic Reduction (SCR) and Selective Non-Catalytic Reduction (SNCR) lower NOx emissions by treating the NOx post-combustion in the flue gas. SCR technology has been used commercially for almost 30 years and is now deployed throughout the world, removing between 80-90% of NOx emissions at a given plant.
Research is under way to develop combined SO2/NOx removal technologies. Such technologies are technically challenging and expensive but new advances hold the promise of overcoming these issues.

Trace Elements

Coal is a chemically complex substance, naturally containing many trace elements including mercury, selenium and arsenic. The combustion of coal can result in trace elements being released from power stations with potentially harmful impacts to both human health and the environment. A number of technologies are used to limit the release of trace elements including coal washing, particulate control devices, fluidised bed combustion, activated carbon injection and FGDs. The choice of mitigation technology will be dependent on the trace elements present and local air quality standard objectives. Research is ongoing to develop better sorbents and reagents that will improve the performance of FGD with respect to trace element removal.

Waste

The combustion of coal generates waste consisting primarily of non-combustible mineral matter along with a small amount of unreacted carbon. The production of this waste can be minimised by coal cleaning prior to combustion. This represents a cost-effective method of providing high quality coal, while helping to reduce power station waste and increasing efficiencies. Waste can be further minimised through the use of high efficiency coal combustion technologies.
There is increasing awareness of the opportunities to reprocess power station waste into valuable materials for use primarily in the construction and civil engineering industry. A wide variety of uses have been developed for coal waste including boiler slag for road surfacing, fluidised bed combustion waste as an agricultural lime and the addition of fly ash to cement (see page on coal combustion products).

Coal & the Environment


Coal, like all other sources of energy, has a number of environmental impacts, from both coal mining and coal use.

Coal mining raises a number of environmental challenges, including soil erosion, dust, noise and water pollution, and impacts on local biodiversity. Steps are taken in modern coal mining operations to minimise these impacts.
Continuous improvements in technology have dramatically reduced or eliminated many of the environmental impacts traditionally associated with the use of coal in the vital electricity generation and steelmaking industries. Viable, highly effective technologies have been developed to tackle the release of pollutants - such as oxides of sulphur (SOx) and nitrogen (NOx) - and particulate and trace elements, such as mercury. More recently, greenhouse gas (GHG) emissions, including carbon dioxide (CO2) and methane (CH4) have become a concern because of their link to climate change.
There is now growing recognition that technology developments have to be part of the solution to climate change. This is particularly true for coal because its use is growing in so many large economies, including the largest and fastest growing countries such as China and India.

Coal and Sustainable Development


In addition to its direct role as an energy resource, coal plays a significant global role in sustainable development. Coal mining is a critical contributor to many economies. Coal directly provides more than seven million jobs worldwide and supports many more millions. Coal production is the key economic activity in many communities. In 2010 the coal industry invested more than US$7 billion in capital expenditures in developing countries.
From providing employment, export and royalty revenues through to local services and the development of infrastructure, coal mining makes a substantial contribution to improving the livelihoods of many.
This is especially true in developing countries where coal mining makes a major contribution to national economies allowing them to grow stronger and address the challenges of poverty and development.
Coal is also a key component of important industrial processes such as steel and cement manufacturing - both of which are central to building the essential infrastructure of growing economies.

Time for Action - Delivering Sustainable Development

Delivering sustainable development is a significant global challenge. Ensuring access to electricity and supporting economic growth is essential to global efforts to eradicate poverty and support human development. Addressing global CO2 emissions is essential to mitigating the impacts of climate change. Managing our environment is essential to conserve biodiversity. These challenges all require coordinated and integrated international action.
WCA's three recommendations for delivering sustainable development are:
  1. An ambitious target for global energy access must be adopted. This target needs to be one that will support the eradication of poverty, the growth of businesses and industries and true economic and social development. National governments and global institutions should work towards an energy target of at least 400MW of installed electrical generation capacity per million of population.
  2. National governments and international institutions must support the rapid deployment of all advanced coal technologies, particularly improved efficiencies at power stations and CCS.
  3. International financial institutions must adopt policies that will allow national governments to determine which energy solutions are appropriate to their needs and support those decisions with the appropriate financial backing.

Coal and Clean Energy


Coal has accounted for the largest increase in energy demand among the full range of energy sources. According to the IEA, the growth in coal usage, in both volume and percentage terms, has been greater than any other fuel.
Coal will play a major role complementing renewable energy sources. It will be one of the key sources of energy to address gaps in wind and solar powered electricity, both of which include risks of intermittent supply.
To meet the huge global demand for energy, all energy sources will be needed. Different sources of energy will suit different countries and different environments. Depending on the availability of natural resources, a decision may be taken between coal and gas as the most viable means of powering base load electricity. In many cases both will have a role to play. Nuclear technology may be available in some countries and not others.
Renewable energy will have a particular role to play in providing off grid electricity and in meeting peak demand. In countries where there is a significant coal resource, it is likely to be the preferred fuel for supplying base load electricity. In many cases this will be a matter of affordability and security.

Energy efficiency

Efficiency in coal-fired power generation will play an important role in the future production of electricity. This is particularly the case with the potential for high efficiency power generation to reduce CO2 emissions. Improving efficiency levels increases the amount of energy that can be extracted from a single unit of coal. Increases in the efficiency of electricity generation are essential in tackling climate change. A single percentage point improvement in the efficiency of a conventional pulverised coal combustion plant results in a 2-3% reduction in CO2 emissions. Highly efficient modern supercritical and ultra-supercritical coal plants emit up to 40% less CO2 than subcritical plants.

Carbon Capture and Storage (CCS)

Carbon capture and storage technology will be a key technology to reduce CO2 emissions, not only from coal, but also natural gas and industrial sources. Figures in the IEA's WEO 2011 report estimate the potential for CCS to contribute 22% of global CO2 mitigation through to 2035. Further analysis by the IEA in their Energy Technology Perspectives 2010 report also shows that climate change action will cost an additional US$4.7 trillion without CCS.

Coal to liquids (CTL)

Converting coal to a liquid fuel - coal liquefaction - allows coal to be utilised as an alternative to oil. CTL is particularly suited to countries that rely heavily on oil imports and have large domestic reserves of coal. South Africa has been producing coal-derived fuels since 1955 and has the only commercial coal to liquids industry in operation today. Not only are CTL fuels used in cars and other vehicles, but South Africa energy company Sasol's CTL fuels also have approval to be used in commercial jets. Currently around 30% of the country's gasoline and diesel needs are produced from indigenous coal. The total capacity of the South African CTL operations stands in excess of 160,000bbl/d.

Underground Coal Gasification (UCG)

In the last few years there has been significant renewed interest in UCG as the technology has moved forward considerably. China has approximately 30 projects using underground coal gasification in different phases of preparation. India plans to use underground gasification to access an estimated 350 billion tonnes of coal.
South African companies Sasol and Eskom both have UCG pilot facilities that have been operating for some time, giving valuable information and data. In Australia, Linc Energy has the Chinchilla site, which first started operating in 2000. Demonstration projects and studies are also currently under way in a number of countries, including the USA, Western and Eastern Europe, Japan, Indonesia, Vietnam, India, Australia and China, with work being carried out by both industry and research establishments.

Coal's Role in Sustainable Energy

Using publicly available figures from Vestas, a large manufacturer of wind turbines, WCA has calculated the amount of coal used in the production of offshore and onshore wind turbines as demonstrated by the infographic below:

BRO COAL PROJECT

BRO COAL PROJECT

BRO COAL PROJECT
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