https://www.miningweekly.com

Future coal consumption depends on adoption of clean coal technologies

16th September 2016

  

Font size: - +

Its is becoming apparent that, in the future, the use of coal is only going to be acceptable if used in clean coal technologies, as the world shifts to a high efficiency, low-emissions and low-carbon economy, says nonprofit coal and energy organisation Fossil Fuel Foundation (FFF). To achieve this cleaner economy, a series of clean coal technologies needs to be adopted.

FFF technical director Professor Rosemary Falcon explains that clean coal technology refers first and foremost to the reduction of the most prominent greenhouse gas, carbon dioxide (CO2), followed by reductions in sulphur oxide (SOx), nitrogen oxide (NOx) and particulates that are formed when using coal-fired power stations.

She points out that the popular methods of emissions reduction in use and their suitability to South African and Southern African conditions are issues seldom discussed. These discussions are necessary as favoured emissions reduction solutions implemented in North America and Europe cannot be replicated here.

“The most widely used method of clean coal technology is the capture of CO2, which is then stored as liquefied CO2 in deep geological formations. However, for geological reasons, there is little if any potential for such storage in the rock formations in South Africa and Southern Africa.”

Falcon notes that there are other reasons why popular clean coal technologies may not work locally. “Firstly, South Africa’s coal is reducing in quality as the best-quality coals have been mined out. Secondly, coals in Southern Africa are of the Gondwana type, which means that they are typically slow to ignite and burn out. This is completely different to the well-known Laurasian coals of Europe and America, which [are used in] many of [to day’s] boilers and gasifiers, and, thirdly, there is little or no opportunity to store CO2 in Southern Africa.”

As a result, it has become necessary to devise other and more innovative ways of reducing emissions. Such methods include increasing efficiencies when combusting South African coals. This can be done in a number of ways, some of which require the introduction of other innovative technologies.

Falcon notes that the country could look into coal beneficiation to upgrade low-grade coals to qualities that are required by boilers that were originally designed for good-quality coals. “New wet and dry systems are being considered here, including the use of wastes and discards long considered of no value. Better-quality coals lead to higher efficiencies and lower CO2 emissions.”

Additionally, the energy industry has also seen the introduction of new combustion technologies that can concentrate CO2 in off gases, or use low-grade coals – including coals with a high ash content that are now being mined – and wastes, such as fluidised-bed technologies. These can also reduce SOx and NOx in the combusting bed through the addition of limestone, which reduces SOx, and applying low temperatures that preclude the production of NOx.

Falcon comments that there are also new gasification technologies that are low-CO2 producers, while some can concentrate the production of relatively pure CO2 for storage, “if a method can be found to do so”.

“Cofiring biomass with coal in combustion or gasification processes can also reduce CO2 emissions significantly, in some cases to virtually zero,” she says, explaining that emission reduction is based on lower coal use. There is also cogeneration, which uses waste heat from coal-firing processes, ultimately ensuring new applications for the same quantity of heat and CO2 and, therefore, offering greater efficiency.

Falcon states that CO2 capture can be viable as long as the CO2 is used in applications, rather than being stored. “This includes the potential to use CO2 for enhanced oil recovery and enhanced methane recovery, the production of advanced materials, such as nanotubes, and in the manufacture of food and other products.”

Innovators can look further into the manufacture of more efficient carbon products for use in the metallurgical industry to more efficiently extract a range of valuable metals – iron, chrome, silicon and manganese.

Falcon emphasises that, given South Africa’s intense reliance on coal, which is used to generate 95% of its power, produce 30% of its liquid fuels and for the production of the bulk of its fertilisers, plastics, paints and explosives, and as a feedstock in the metallurgical processing of iron, steel and ferroalloy metals, it is of vital importance to find alternative ways to continue to use coal in as clean and sustainable a manner as possible.

Therefore, a wholesale reduction in South Africa’ coal consumption is not viable or even necessary. Falcon points out that, as a developing country, South Africa requires abundant, secure, reliable and cost-effective energy to increase its industrialisation and meet the needs of its economy. Hence, reducing the use of the country’s major, abundant and inexpensive energy resource in favour of alternative, but intermittent, sources of energy does not make economic sense.

“Coal is the most variable and most valuable chemical of all mineral commodities, as well as a source of heat and power. It should be protected, nurtured and used wisely.”

Edited by Tracy Hancock
Creamer Media Contributing Editor

Comments

The content you are trying to access is only available to subscribers.

If you are already a subscriber, you can Login Here.

If you are not a subscriber, you can subscribe now, by selecting one of the below options.

For more information or assistance, please contact us at subscriptions@creamermedia.co.za.

Option 1 (equivalent of R125 a month):

Receive a weekly copy of Creamer Media's Engineering News & Mining Weekly magazine
(print copy for those in South Africa and e-magazine for those outside of South Africa)
Receive daily email newsletters
Access to full search results
Access archive of magazine back copies
Access to Projects in Progress
Access to ONE Research Report of your choice in PDF format

Option 2 (equivalent of R375 a month):

All benefits from Option 1
PLUS
Access to Creamer Media's Research Channel Africa for ALL Research Reports, in PDF format, on various industrial and mining sectors including Electricity; Water; Energy Transition; Hydrogen; Roads, Rail and Ports; Coal; Gold; Platinum; Battery Metals; etc.

Already a subscriber?

Forgotten your password?

MAGAZINE & ONLINE

SUBSCRIBE

RESEARCH CHANNEL AFRICA

SUBSCRIBE

CORPORATE PACKAGES

CLICK FOR A QUOTATION