View source for Refined coal

{{Cleanup bare URLs|date=September 2022}}
'''Refined coal''' is the product of the '''coal-upgrading technology''' that removes moisture and certain pollutants from [[coal rank|lower-rank]] coals such as [[sub-bituminous]] and [[lignite]] (brown) coals, raising their calorific values.<ref name="NextGen Energy Council Breakthrough Paper">http://www.nextgenenergy.org/Portals/Nextgen/docs/TechPapers/NextGen_EEE_Clean_new.pdf NextGen Energy Council Breakthrough Paper</ref> Coal refining or upgrading technologies are typically pre-combustion treatments and processes that alter the characteristics of coal before it is burned. Pre-combustion coal-upgrading technologies aim to increase efficiency and reduce emissions when coal is burned. Depending on the situation, pre-combustion technology can be used in place of or as a supplement to post-combustion technologies to control emissions from coal-fueled boilers.<ref name="Pre Combustion Innovations Alliance">http://www.fmifuel.com/pcia/index.html Pre Combustion Innovations Alliance</ref> A primary benefit of refined coal is the capacity to reduce the net volume of carbon emissions that is currently emitted from power generators and would reduce the number of emissions that is proposed to be managed via emerging [[carbon sequestration]] methodologies. Refined coal technologies have primarily been developed in the United States. Several similar technologies have been researched, developed, and tested in [[Victoria (Australia)|Victoria]], Australia, including the [[Densified coal]] technology ([[Coldry Process]]) developed to alter the chemical bonds of brown coal to create a product that is cleaner, stable (not prone to spontaneous combustion), exportable and of sufficiently high calorific value to be a [[black coal equivalent]].

== Coal-upgrading technology ==
'''Coal-upgrading technology''' refers to a class of technologies developed to remove moisture, and certain pollutants from  [[coal rank|low rank]] coals such as sub-[[Bituminous coal]] and [[lignite]] ([[brown coal]]) and raise their calorific values. Companies in Australia, Germany, and the United States are the principal drivers of these technologies' research, development, and commercialization.{{citation needed|date=May 2013}}

=== Environmental rationale ===
{{unsourced section|date=May 2023}}
Around 30 nations collectively operate more than 1,400 brown coal-fired power stations worldwide. Brown coal power stations that cannot economically dewater brown coal are inefficient and cause high levels of [[carbon emissions]]. High-emitting power stations, notably the [[Hazelwood power station]] in [[Australia]], attract environmental criticism. Many modern economies, including [[Greece]] and [[Victoria (Australia)|Victoria]] (Australia), are highly dependent on brown coal for electricity. Improved environmental performance and the need for stable economic environment provide incentives for investment to substantially reduce the negative environmental impact of burning raw ('as mined') brown coal.

=== Economic rationale ===
Coal-upgrading technologies remove moisture from 'as mined' brown coal and transform the calorific performance of brown coal to a 'cleaner' burning status relatively equivalent to high calorific value black coal. Some coal-upgrading processes result in a [[densified coal]] product that is considered to be a [[Black coal equivalent]] product suitable for burning in black coal boilers.

Victorian brown coal, with a characteristic moisture content of 60% by weight, is regarded as the world's 'wettest' brown coal. The high moisture content is the key reason the state's three major power stations are collectively regarded as the dirtiest carbon emitters in the world. Studies undertaken by the [[University of Melbourne]]<ref>Reactivity and Reactions of Australian brown coals. R.B. Johns and A.G. Pandolfo Dept Organic Chemistry, University of Melbourne. 1980 
</ref> and [[Monash University]] confirm that when moisture is removed from Victorian brown coal, naturally low levels of ash, sulfur, and other elements rank it as being one of the cleanest coals in the world. When dewatered, upgraded brown coal can compete in the export market at comparable prices to black coal.

With significant brown coal mining occurring worldwide and mining levels increasing, the need for coal-upgrading technologies has become more apparent. the technologies will help to address the global environmental concern of rising emissions from the burning of brown coal and provide alternative fuel options to rapidly emerging economies such as Vietnam that face difficulty competing for black coal with China, India, Japan, and other nations.

{| class="wikitable sortable"  style="text-align:right"
|+Lignite mined in millions of [[metric ton]]s{{Citation needed|date=July 2010}}
! Country                          ||  1970 ||  1980 ||  1990 ||  2000 || 2001
|-
|align=left|{{Flag|Germany}}       || 369.3 || 388.0 || 356.5 || 167.7 || 175.4
|-
|align=left|{{Flag|Russia}}        || 127.0 || 141.0 || 137.3 ||  86.4 ||  83.2
|-
|align=left|{{Flag|United States}} ||   5.4 ||  42.3 ||  82.6 ||  83.5 ||  80.5
|-
|align=left|{{Flag|Australia}}     ||  24.2 ||  32.9 ||  46.0 ||  65.0 ||  67.8
|-
|align=left|{{Flag|Greece}}        ||   8.1 ||  23.2 ||  51.7 ||  63.3 ||  67.0
|-
|align=left|{{Flag|Poland}}        ||  32.8 ||  36.9 ||  67.6 ||  61.3 ||  59.5
|-
|align=left|{{Flag|Turkey}} || 4.4 || 15.0 || 43.8 || 63.0 || 57.2
|-
|align=left|{{Flag|Czech Republic}} || 67.0 || 87.0 || 71.0 || 50.1 || 50.7
|-
|align=left|{{Flag|People's Republic of China}} || 13.0 || 22.0 || 38.0 || 40.0 || 47.0
|-
|align=left|{{Flag|SFR Yugoslavia}} || 26.0 || 43.0 || 60.0 || - || -
|-
|align=left|{{Flag|Serbia and Montenegro}}|| - || - || - || 35.5 || 35.5
|-
|align=left|{{Flag|Romania}} || 14.1 || 27.1 || 33.5 || 17.9 || 29.8
|-
|align=left|{{Flag|North Korea}} || 5.7 || 10.0 || 10.0 || 26.0 || 26.5
|-class="sortbottom"
!Total                           !! 804.0 !! 1,028.0 !! 1,214.0 !! 877.4 !! 894.8
|}

=== Technology comparison ===
{{Unreferenced section|date=May 2013}}

Because of inherent high moisture content, all lignites need to be dried prior to combustion. Depending on the technology type drying is achieved either via a discrete operation or part of a process. The comparison chart identifies different technology drying methods that are in development in different countries and provides a qualitative comparison.

{| class="wikitable"
|-
! Option!! Drycol!! ZEMAG<ref group="note">ZEMAG Clean Energy Technology, Germany</ref>!! Coldry Process<ref group="note">Coldry Process, ECT Limited, Australia</ref>!! RWE-WTA<ref group="note">RWE-WTE = RWE (Rhenish-Westphalian Electric) WTE technology</ref>!! HTFG<ref group="note">HTFG = Delta Drying Technology Ltd</ref>!! WEC-BCB<ref group="note">WEC-BCB = White Energy Company, Binderless Coal Briquetting</ref>!! UBC<ref group="note">UBC = Upgraded Brown Coal Process, Japan Coal Energy Center & Kobe Steel Ltd.</ref>!!Exergen CHTD<ref group="note">Exergen company, Continuous Hydrothermal Dewatering technology</ref>!! MTE<ref group="note">MTE = Mechanical Thermal Expression, develop|ed by the CRC for Clean Power</ref>!! Kfuel<ref group="note">KFuel = Koppelman Fuel, Evergreen Energy, Denver, Colorado, USA</ref> !! LCP<ref group="note">LCP = LiMaxTM Coal Process Technology, developed by GB Clean Energy</ref><ref>{{cite web |url=http://www.gbce.com/en/technology_process.php |title=GBCE |accessdate=2013-03-25 |url-status=dead |archiveurl=https://web.archive.org/web/20150628120913/http://www.gbce.com/en/technology_process.php |archivedate=2015-06-28 }}</ref>
|-
| '''Country of origin''' || United States|| Germany || Australia || Germany || China || Australia|| Indonesia/Japan || Australia|| Australia || United States || China
|-
| '''Process Description''' || Drycol Microwave Drying|| indirect contact drying in tubular dryers
 || exothermic reaction. natural evaporation. accelerated drying at 25-30&nbsp;°C
 || fluidised bed stream drying
 || High temp flue gas fluidised bed drying
 || flash dry coal fines. use pressure to form briquettes
 || mixing crushed coal with oil, heating the mixture to 130-160&nbsp;°C under 19-19.5 Bar pressure, separating the slurry cake from the oil by a centrifuge and then drying and briquetting it
 || Continuous Hydrothermal Dewatering decarboxylation reaction in the slurry form at 300 degC and 100 Bar, followed by gas/liquid/solid separation and press drying
 || heat and squeeze at 250&nbsp;°C and 125 Bar, express water from coal
 || heat and squeeze at 200&nbsp;°C and 100 Bar
 || pyrolytic process that employs heat and pressure in an oxygen-free environment to continue the coalification process that occurs naturally in the earth
|-
| '''Drying Description''' || Microwave Drying while keeping coal below 90 deg C|| drying achieved using low pressure steam of max. 180&nbsp;°C, 4 bar || drying achieved using low-temperature waste heat to provide evaporative drying || drying achieved using >100&nbsp;°C low pressure steam || drying achieved using >900&nbsp;°C flue gas to dry 0–50&nbsp;mm raw coal with 2-4% system O2 concentration under slight positive pressure || drying achieved via exposure to high pressure combustion stream (flash drying)|| drying achieved by exposure to 130-160&nbsp;°C under 19-19.5 Bar pressure in oil slurry || drying achieved by exposure to high pressure and temperature in a vertical autoclave, followed by a flashing step || drying achieved via high pressure and temperature compression || drying achieved via high pressure and temperature compression || The process employs no additives and extracts both surface and inherent moisture. 
|-
| '''Grade of heat used for drying''' || Very Low|| Low || Low || Medium || Low || High|| Medium || Medium || High || High || Medium
|-
| '''Alternative uses for energy consumed in drying''' || None|| power generation || none || power generation || coal sales (fines used for combustion || coal sales (fines used for combustion || n/a || electrical energy || electrical energy || electrical energy || power generation
|-
| '''Pretreatment requirement''' || Sizing for material handling|| crushing/screening (normal) || (normal) plus mechanical mastication and extrusion || (normal) || crushing/screening to 50&nbsp;mm || (normal) || crushing and mixing wit 
|-
| '''CO2 exposures''' || n/a || n/a || Up to 40% reduction in CO2. Net beneficial CO2 position due to low heat and low pressure || Up to 30-40% CO2 reduction from the boiler. (Lost steam energy utilised in fluid bed dryer not accounted for) || Up to 25-35% CO2 reduction from the boiler || zero net improvement due to energy source for drying is coal combustion || n/a || Up to 40% reduction in CO2 || ~15% CO2 reduction in combustion (detailed analysis not available). Zero net improvement due to energy used for heating and compression || ~15% CO2 reduction in combustion (detailed analysis unavailable). Utilises energy for heating and compression || n/a
|-
| '''Waste streams generated from drying'''  || clean water ||none || none || none || none || none || waste water stream  || none  || waste water stream  || waste water stream  || none 
|-
| '''Byproduct streams possible''' || none || none || demineralised water || none || none || none || n/a ||  demineralised water || none || none || tar product
|-
| '''Coal output stream description''' || Direct use ||for briquetting/exporting or power generation || coal pellets for use and export || input coal for power generation only || coal for sale or power generation || coal briquettes for use and export || coal briquettes for use and export || coal for use and export || input coal for power generation only || input coal for power generation only || exportable coal for power generation
|-
| '''Coal output moisture level''' || 10 - 30% || 5-20% || 12-14% || 12-14% || 6-30% || 10-15% || n/a || 5-10% || ~18% || ~20% || 1-15%
|-
| '''Coal output - transportable or exportable''' || long-distance transport ||long-distance transport || non-pyrophoric || direct to boiler only || short-distance transport || non-pyrophoric || non-pyrophoric ||  non-pyrophoric || pyrophoric || pyrophoric || hydrophobic, transportable & exportable
|-
| '''Industrial maturity''' || Technology in food industry 35 years ||well established and proven technology, industrial plants of up to 3 MTPA capacity running in Germany and the Czech Republic || pilot plant operational for 7 years; extensive database of global testing; commencing feasibility for full-scale commercial operation by 2014 || commercial operations in several locations ||It was used for coking drying since 1955 for over 200 wash plants || one commercial scale plant, operations have not exceeded 30% of nameplate capacity || pilot plant operational, demonstration plant 2008-2011 || Pilot Plant 2002 - 2008, ready for commercialisation. Tested on Victorian and Indonesian coals  || pilot plant abandoned || pilot plant operational || 1MTPA plant in Inner Mongolia fully operational since 2012
|}
{{reflist|group=note}}

== History and advantages ==

=== United States ===
The best known producer of refined coal is a company based in Denver, Colorado called [http://www.evgenergy.com Evergreen Energy Inc.]. The company is publicly traded and is listed on the [[NYSE Arca]] exchange. According to the [http://www.evgenergy.com company's website] and its Form 10-K on file with the U.S. Securities and Exchange Commission, it was founded in 1984 to commercialize a coal-upgrading technology first developed in a Stanford University laboratory by [[Edward Koppelman]]. Taking the K from Koppelman's name, Evergreen, formerly KFx Inc., branded its refined coal product as "K-Fuel."

Much of the coal in the western United States is known as "lower-rank" coal that falls under the categories of "sub-bituminous" and "lignite" coals. These coals have high moisture levels and can be 20 to 30 percent water. This relatively high moisture content compared to "higher rank" coals like bituminous and anthracite coals make lower-rank coals less efficient. The average heat content of sub-bituminous coal consumed in the United States is approximately 8,500 British thermal units (Btu) per pound. The K-Fuel(R) process uses heat and pressure to remove approximately 30 percent of the moisture from raw, low-rank coal and raises its thermal content to approximately 11,000 Btu per pound.<ref name="NextGen Energy Council Breakthrough Paper" /> In addition to raising the coal's heat value, a significant amount, up to 70 percent, of the elemental mercury in the coal is removed and, because of its higher efficiency, lower chloride and nitrogen oxides emissions are achieved on a per kilowatt hour generated basis.<ref name="Black Hills TGest Burn Results">http://evgenergy.com/documents/BHP_Results_ES.shtml Refined Coal Test Burn Results Black Hills Power</ref>

The advantages of the refined coal process are more efficient transportation and the ability of utilities to switch to a fuel made of 100 percent refined coal or a blend of raw and refined coals in order to achieve lower emissions and greater efficiency.<ref name="Pennsylvania Test Burn Results">http://evgenergy.com/documents/EEE-PA-Test-Burn-Ex-Summary.pdf Test Burn Results with Pennsylvania Utility</ref> A disadvantage is that the industry requires significant subsidies.  An examination of government figures show that in 2007, for every [[kilowatt hour|megawatt-hour]] generated, refined coal received $29.81 in federal support, [[Solar power in the United States|solar power]] received $24.34, [[Wind power in the United States|wind power]] received $23.37, and [[Nuclear power in the United States|nuclear power]] received $1.59.<ref>{{cite web
  | title = Federal Financial Interventions and Subsidies in Energy Markets in 2007
  | publisher = [[Energy Information Administration]]
  | url = http://www.eia.doe.gov/oiaf/servicerpt/subsidy2/pdf/execsum.pdf
  | accessdate = }}</ref>

=== Australia ===
The producer of densified coal in Australia is a company based in [[Melbourne]], Victoria called '''Environmental Clean Technologies Limited''' (ECT Limited)<ref>[http://www.ectltd.com.au Environmental Clean Technologies Limited]</ref> The company is publicly traded and listed on the [[Australian Stock Exchange]] (ASX). The company was listed in 2005 with the primary purpose of commercialising the [[Coldry Process]] coal-upgrading methodology first developed in the Chemical Laboratory of [[Melbourne University]] by Dr B. A. John in the 1980s. The name of the process derived from the '''Calleja Group''', which acquired the technology in 1994 and developed the technology to pilot demonstration at [[Maddingley Mine]], [[Bacchus Marsh]], Victoria in 2004 before licensing the technology to ECT Limited for further commercialisation in 2005.

The State of Victoria contains approximately 25% of the world's known reserves of brown coal (lignite). This coal is also amongst the world's 'wettest' coal, with a typical moisture content of 60 per cent water by weight. High moisture content makes Victorian brown coal an inefficient fuel source and is the primary reason why the [[Hazelwood power station]] in the Latrobe Valley is regarded as the world's dirtiest coal-fired power station. The Coldry Process uses low-pressure mechanical shear to create a natural exothermic reaction within the coal that then naturally expels 80 per cent of the moisture content. Expelled moisture is then captured and recovered as distilled water. Victorian brown coal transformed by the Coldry Process has a raised thermal content of 5874 kcal/kg, which is comparable to most export-grade Australian black coal.

The advantage of the Coldry Process is its ability to allow power generators to switch to a blend of raw as mined brown coal and Coldry pellets to achieve lower emissions in existing inefficient boilers, or achieve substantially less emissions by introducing black coal boilers and using 100 per cent Coldry refined coal pellets as a black coal equivalent. The Coldry Process provides the added advantage of creating new revenue streams for power generators through the production of a product that can be exported to other countries as a replacement for black coal. Unlike other refined coal processes, the Coldry Process is a commercial methodology that does not require subsidy.

== Commercial development ==
{{Advert|section|date=May 2013}}

=== United States ===
Evergreen Energy constructed a full-scale coal refinery near [[Gillette, Wyoming]] that began operation in late 2005. Designed originally to be a commercial plant, the facility encountered design and operational problems. Evergreen idled the facility in March 2008<ref name="Evergreen Energy Letter to Shareholders">http://www.evgenergy.com/documents/2008-03-20-EEE_Shareholder_Letter.shtml Evergreen Letter to Shareholders March 2008</ref> and instead used the plant as a process development platform with its engineering, construction and procurement contractor Bechtel Power Corporation.

Evergreen is now seeking to construct a coal refinery using the improved Bechtel design at locations in the Midwestern United States and in Asia.<ref name="Evergreen Letter to Shareholders">http://www.evgenergy.com/documents/2008-11-10-EEE_Shareholder_Letter.shtml Evergreen Letter to Shareholders November 2008</ref>

=== Australia ===
Calleja Group constructed a full-scale 16,000 tonne per annum pilot demonstration plant at '''JBD Business Park''' at Maddingley Mine near Bacchus Marsh, Victoria that began operation in early 2004. From 2005 ECT Limited upgraded the facility, added a water recovery process with Victorian Government funding in 2007 and operated the plant as a process development platform with its engineering partner [[Arup Group Limited|ARUP]].  In 2009 ECT Limited secured and agreement with '''Thang Long Investment Company''' '''(Tincom)''' of [[Vietnam]] to finalise commercial feasibility ahead of construction of a 2 million tonne pa export plant by 2014 and 20 million tonne pa export by 2020.
ECT Limited is using the ARUP improved design to secure technology licensing agreements with brown coal suppliers in [[China]], [[India]], [[Indonesia]], [[Poland]], [[Greece]] and [[Russia]].

=== China ===
GBCE has built and is now operating the world's first industrial-scale coal-upgrading facility. It has capacity to process 1 MTPA of coal feedstock and is located in Holingol, Inner Mongolia, the largest lignite-producing region in China.<ref>http://www.gbce.com/en/projects_yield.php</ref> The coal is typically high moisture (35 – 40% TM) and 3200 – 3400 kcal gar.  Depending on market requirements, it produces 5000–5500 kcal coal (gar) with greatly reduced moisture content (< 10% gar). The plant uses LCP [[coal-upgrading technology]], which is a pyrolytic process that employs heat and pressure in an oxygen-free environment to continue the coalification process that occurs naturally in the earth. The processed coal by this technology is hydrophobic and transportable, which means it will not reabsorb moisture or break up into powder during transportation.

== See also ==
{{Portal|Energy}}
* [[Bituminous coal]]
* [[Bergius process]]
* [[Coal assay]]
* [[Coldry Process]]
* [[Coke (fuel)|Coke fuel]]
* [[Densified coal]]
* [[Energy value of coal]]
* [[Fischer–Tropsch process]]
* [[Karrick process]]
* [[Leonardite]]
* [[Lignite]]
* [[Maddingley Mine]]
* [[Orders of magnitude (specific energy density)]]
* [[Greenhouse gas#Relative CO2 emission from various fuels|List of CO<sub>2</sub> emitted per million Joule of energy from various fuels]]

== References ==
{{Reflist}}
{{coal}}

[[Category:Coal]]