thyssenkrupp energy
thyssenkrupp energy
Comminution, the crushing and grinding of ore, is the most energy intensive step in mining and can account for >53% of total energy used in mineral processing operations.

It also accounts for 4% of the world’s total electrical energy consumption which in today’s economic climate leads to the question – how do we make it more efficient and self-sustaining? thyssenkrupp not only offers efficient comminution solutions for the mining sector, but also spearheads the inclusion of power generation solutions to reduce overall energy costs.

 

thyssenkrupp utility scale redox flow battery
thyssenkrupp utility scale redox flow battery

Ore grades around the world are also continuing to decline, requiring more energy to move and treat additional waste material, so efficient comminution are  increasingly more relevant.

Comminution is on the critical production path of any mining operation. It is also a major energy consumer and the reliability and energy efficiency of the comminution plant is critical to the success of any mining and minerals processing operation.

The inherent energy requirement of various comminution methods is dependent on the nature of the material being processed, the type of equipment and its operating condition.  A very critical element of the process success is the basic reliability and cost of energy supply to a comminution plant.

 

thyssenkrupp energy
thyssenkrupp energy

Efficient comminution

There are a number of integrated strategies and new grinding technologies which can improve efficiencies and reduce energy use.

The following are just a few of the strategies leading-edge companies are putting in place to successfully reduce their comminution costs and improve throughput.

Energy efficient grinding technologies can improve the input of energy going into the grinding process in some cases by as much as 40%. Choosing high pressure grinding rolls (HPGR) over semi-autonomous grinding (SAG) equipment has also been shown to deliver energy efficiencies of 10 – 15%.

Power plant solutions

Africa is blessed with energy resources, yet they go largely untapped. As a result, only one in three Africans has access to energy, which stymies economic growth on the continent and seriously limits human potential and well-being. If nothing changes, Sub-Saharan Africa as a region will actually see the number of people without electricity increase from 590 million in 2013 to 655 million by 2030. (source: World Bank, Power of the Mine).

Mining demand for power is expected to triple by 2020 from 2000How can an energy-intensive, high-volume customer such as the mining industry improve its contribution to energy supply, help expand access, and attract private capital into the space?

thyssenkrupp energy
Source: Africa Power–Mining Database 2014, World Bank, Washington, DC. Note: CAGR = compound annual growth rate

In mining and processing plants one of the critical cost drivers is the cost of energy and similarly, the production throughput is directly linked to the reliability of supply.

On a continent that has a permanent energy shortage plus a population with growing demand which forces the allocation priorities of governments and utilities, unfortunately resulting in quality of supply problems and, even worse, the escalating cost makes energy supply to mining operations critical.

The World Bank in a recent publication “The Power of the Mine”  positions the development thinking around embracing mining operations as economic and society growth nodes. The authors extend this logic by arguing that the mine should also be encouraged to generate its own electricity requirements and be encouraged to also supply local communities and the national grid.

This implies higher capital investment requirements but, possibly with developmental finance and the right government incentives, this may become economically viable.

Historically industrial development has been driven by fossil fuels but environmental pressure is driving a major shift towards renewable and lower impact fuels such as natural gas. These developments are in the process of fundamentally changing the electrical energy generation, transmission and distribution environment.

This revolution has not only driven down prices of renewable to the point where they can compete on price with conventional generation but has also created motivation for the development of various energy storage technologies and even new fuels such as hydrogen.

The pressure is also relentless on innovation around engines and turbines to use higher quality fuels. The pressure to upgrade the quality of diesel specifications from Euro 2 to Euro 4 or 5 is placing a lot of challenges on refineries in Africa to upgrade and invest.

As a technological multinational thyssenkrupp has approached these developments as major opportunities.  On the one hand, our technology teams have developed energy storage solutions such as the redox flow batteries and hydrogen storage systems as well as the experience of our power teams specifically in India has created practical solutions for a developing environment.

Captive power plants

The experience with industrial clients in India has shown that our circulating fluidised bed combustion (CFBC) conventional captive power stations has become a standard feature of many industrial sites.

By creating an efficient ‘feed-in tariff’ bidding and payment system the government of India has facilitated and assisted industrialists with funding these distributed captive power stations throughout India.

[quote]Currently about 25% of the aggregated Indian generating capacity comes from these small captive facilities. In southern Africa especially, with the widely available Karoo coals and the large amounts of washery rejects created, the use of these CFBC boilers to clean up an environmental risk has high value. Other thermal solutions include biomass boilers and using city waste as a fuel.

On the storage side thyssenkrupp Industrial Solutions has developed an energy storage solution based on approximately 600 electrochemical plants that it has built. By utilising the similar hardware thyssenkrupp has developed world-scale Redox Flow batteries.

These will be stationary facilities which will be able to service captive power needs in the 10s and 100s of MW range for greater than 4  hours of energy storage.

Captive power plant

These facilities will substantially change the nature of the planning and operation of power systems,  enabling techniques like storing electricity when it is abundant and/or low cost then using it when the supply/demand gets out of balance, saving money and using resources more efficiently.

Energy storage systems will be able to substantially bring down the cost of comminution /mining electrical energy while substantially increasing the quality of supply and especially the reliability.

Redox flow batteries store electricity as chemical energy in two large tanks. The tanks are filled with dissolved salts s. The tanks are connected with electrochemical cells via which the batteries are charged and discharged. Redox flow batteries have excellent efficiency, and provide low levelized energy costs, due to their long service life.

The global market for energy storage systems is growing rapidly as renewables become increasingly established on the energy market. According to forecasts by the International Energy Agency (IEA), electricity generation from renewable sources will roughly triple between 2012 and 2040.

The problem is that wind and solar are volatile; the amount of energy they deliver fluctuates sharply. To store large amounts of energy from renewable resources, flexible storage systems such as redox flow batteries will be needed in the future.

Redox flow batteries are particularly suitable as stationary energy storage systems. They can respond very quickly to the supply situation, switching from storage to discharge in fractions of a second and independently allowing for the increase of power or storage hours by increasing battery stacks or electrolyte.

thyssenkrupp Industrial Solutions has been working for some time on redox flow storage technology for large-scale use, drawing on its world-leading experience in brine electrolysis. The company’s know-how includes the design of the electrochemical cells and decades of experience in industrial scale electrochemical plant engineering, procurement, construction and safety.

Conclusion

For thyssenkrupp the development and application of these technologies to the performance advantage of the equipment we provide and plants we build, remains a major focus. There is little doubt that these technologies will find much application into mining and mineral processing facilities in Africa soon.

Emphasis is placed on ensuring we can deliver safe and environmentally friendly products and processes that are as efficient as possible with fewer operating costs.

For more information please contact:

Thabo Molekoa – CEO: South east Africa

Thabo.Molekoa@thyssenkrupp.com

T: +27 11 236-1016

Dr. Wilfred Barkhuizen – General Manager: Mineral Processing, Power & Energy

Wilfred.barkhuizen@thyssenkrupp.com

+27 11 236 1318