Brazilian Nickel is developing the Piauí Nickel Project in northeastern Brazil with the aim of becoming one of world’s major producers of nickel to supply the growing electric vehicle battery market and provide an alternative to existing global supply chains that are controlled by just a few countries.

The Piauí project has reserves of 104 million tonnes at 0.82% nickel and 0.05% cobalt, with upside potential in adjacent exploration licences. We expect peak production to reach more than 34,000t Nickel and 1050t cobalt and average, over the first 10 years of the operation, 25,000 tonnes per year of contained nickel. Further Brazilian Nickel has received all the necessary installation licenses, meaning it can proceed quickly with construction once financing finalized.

Brazilian Nickel chose to use heap leaching for all the processing at the Piauí project because of its long list of environmental and economic advantages. Heap leaching has the potential to be the lowest capital and operating cost and most environmentally friendly of the processes to recover nickel from laterite ores. It is a low-CO₂ process that uses water efficiently and only produces solid residues, which eliminates the need for an environmentally risky tailings dam. Importantly, it is also a more simple, flexible process and thus is very suitable for remote locations and training of local workforces to operate.

Although heap leaching has not been used for nickel laterite processing on this scale before, it is not an untried or experimental technology. Heap leaching is well established process used for the treatment of copper, gold and uranium. Work first began on nickel laterite heap leaching in the 1990s and the core BRN metallurgical team has been working to commercialise it on a large scale since the early 2000s.

Many aspects of heap leaching technology used for other metals are transferable to nickel laterite processing, though it takes a high degree of expertise. Our metallurgical experts have optimized the process over the years to suit the many deposits studied. The key to heap leaching of nickel laterites is actually iron control and our optimized process does exactly that.

Iron is an impurity in the ore in varying degrees of concentration in different deposits and BRN’s heap leach process minimizes the amount going into solution, basically selectively leaching nickel over the iron. This results in a pregnant leach solution (PLS) with the highest nickel and the lowest iron and acid concentration resulting in a smaller more efficient downstream treatment plant.,.

Since purchasing the Piauí project in 2014 BRN has further demonstrated and improved the process specifically to the conditions at Piauí. The company operated a demonstration plant on the Piauí site with full height heaps in 2016 & 2017, producing nickel and cobalt products that were exported and sold.  In 2021 the demonstration plant was expanded to form the PNP1000, a small-scale operation that ran until the end of 2023, producing nickel and cobalt contained in a Mixed Hydroxide Precipitate (MHP) which was fully qualified by the EV battery cathode value chain.

The ore from the Piauí Nickel Project has excellent metallurgical properties for heap leaching, being high in silica. This results in fast leach kinetics, high nickel and cobalt extractions and, most importantly, low acid consumption. This cements the project as a highly viable, low cost, and low impact method of providing a vital resource for the green economy.

In short, nickel laterite heap leaching is simple and flexible, economically sound and environmentally responsible, and can be applied to the many laterite deposits that currently have no realistic path to production.

Fundamentals of Heap Leaching

In the heap leaching process, very dilute sulfuric acid (similar in strength to some acid‐based household cleaning products) is slowly applied to crushed and agglomerated nickel ore on a lined pad to dissolve the nickel and cobalt contained in the ore. The resulting metal-rich solution is then treated in an ambient temperature and pressure process to firstly remove impurities by precipitation with limestone and then to recover the valuable nickel and cobalt from solution. This is done with a combination of ion exchange circuits and further precipitation to MHP.  

Solutions are continuously recycled, reducing waste and making the process more sustainable.
The final product is an intermediate mixed hydroxide precipitate (MHP) containing ~50% nickel and ~2% cobalt that can then be sold to a large customer base of existing nickel refiners along with the newer EV battery precursor and Cathode Active Material (CAM) producers.

While Brazilian Nickel believes that any nickel laterite is amenable to heap leaching, factors including terrain, weather and distance to ports are crucial in developing a commercially successful project.

Technical Advantages vs. Alternatives Of Heap Leaching

Heap Leaching has much better resource utilization than other processes that treat nickel laterites. Once selected as ore, material is stockpiled and reclaimed to give the right homogeneous mix in the heap. Nickel extraction in the Piauí project is above 80% and downstream losses less than 5% giving a range of global recovery of 76-82%.

Smelting and high-pressure acid leaching (HPAL) typically have recoveries from the target ore zone of 85% to 95%, however these processes have a very specific target ore and therefore total resource recovery is normally in the range of 45% to 60%.

HPAL, currently the hydrometallurgical process of choice for nickel laterites outside of China, uses elevated temperatures (around 255°C) and pressures (around 50 bars) along with sulfuric acid to extract nickel and cobalt from laterite ore. This is much more energy intensive and capital intensive than heap leaching and involves more complex

Most other pyrometallurgical processes, notably ferronickel, nickel pig iron and matte smelting, require a high-energy-intensity smelting process. While HPAL has a lower energy intensity than smelting, estimates suggest that for every tonne of nickel ore processed via HPAL, around 1.5 tonnes of waste is also produced. Typically

Environmental & Sustainability Considerations Of Heap Leaching

Sustainability is a core value at Brazilian Nickel. The Brazilian state is also very focused on environmental issues in mining, and rightly so, given some of the major disasters at mining operations in the past.

In addition to having only dry residues the heap leach process is inherently lower CO₂ than other laterite processes. We also have active research programs to capture and reduce what CO₂ we do emit with the aim of zero carbon production in the future.

The Piauí Nickel full-scale Project will have an on-site acid plant as part of the operation. This means sulphur is transported to the site rather than more dangerous acid shipments. The sulphur burning acid plant cogenerates more than enough electricity to operate the HL operation and usually allows some sale of power back to the country’s grid.

Heap leaching also bypasses the need for fine milling, reducing energy consumption and environmental impact. Furthermore, the process can be applied to low-grade ores that are not economically viable using conventional techniques.

Sustainability is also about what we leave behind. Our objective is to leave behind a positive legacy of stronger, more sustainable communities once mining activities cease. This involves planning and community buy in before, during and after the period of actual mining. I think we’re doing a pretty good job of it, Brazilian Nickel’s Piauí Nickel Metais unit, which operates the Piauí site was awarded the prestigious Nickel Mark award for its unwavering commitment to responsible and sustainable practices across the nickel value chain. While this gives us confidence that we’re on the right track, we are always looking for ways to do more.

Anne Oxley

Anne is the co-founder of Brazilian Nickel a company with sustainability and ethical principles at the forefront of its Agenda. Its flagship Piauí Nickel Project is a nickel heap leach which produced its first intermediate products in 2022. Heap leaching is a low cost and inherently low carbon footprint process and BRN is looking at innovative ways to reduce the project carbon footprint even further with the vision of being carbon negative The Piauí site was awarded the Nickel Mark in May 2024. BRN is a member of the Nickel Institute (the global association of leading primary nickel producers) and in 2025 Anne became Chair of its Board of Directors.

In 2022 Anne was named one of the 25 inaugural ESG champions by the Natural Resources Forum particularly for her work on gender diversity and inclusivity in the mining sector.

Anne is a Chartered Metallurgical Engineer from the Royal School of Mines, Imperial College London. She has over 30 years’ experience in the natural resource sector and has been working in nickel and cobalt since 2003. She is also a scientific associate of the Natural History Museum in London were she continues to contribute to fundamental nickel and cobalt research.

The post Behind Heap Leaching | Mechanics & Technology of Nickel Heap Leaching appeared first on Engineeringness.

Zaidi, A., de Leeuwe, C., Chansai, S., Hardacre, C., Garforth, A., Parlett, C., & Spallina, V. (2025). Development of iron-nickel containing perovskites with increased oxygen carrier capacity for chemical looping H2 production. Journal of Environmental Chemical Engineering, 13(1), 115069. https://doi.org/10.1016/j.jece.2024.115069

One of the earliest reference to chemical looping combustion is Lewis and Gilliland, in 1954, publishing ‘Production of Pure CO₂‘ (patent US2665972A), which described a concept like chemical looping combustion, as well the idea of using oxygen carriers to reduce fuels [2]. In the 1980s Richter and Knoche proposed the principle of chemical looping combustion (CLC) to improve fossil fuel power plants [3].

The name CLC was first used by Ishida in the 1980s in a study to reduce exergy losses in natural gas power plants when converting fuel energy into thermal energy [4]. In 1994 Ishida and Jin continued research for the integration of CLC in power plants. They developed a new system for power generation to reduce the exergy destruction caused by combustion and heat exchange and solve the environmental issues associated with CO₂ by recovering and utilising it [5].

In the early 2000s, CLC hadn’t been demonstrated on a large plant scale with only a handful of test cycle runs, with the small number of oxygen carries being investigated [6].

The EU funded CO₂ capture program provided the first notable trial for CLC [7], with the experiment used more than 300 different types of oxygen carriers [8]. Another EU project was the ‘CO₂ Capture and Hydrogen Production from Gaseous Fuels’ (CACHET). This project focused on the different applications for hydrogen production and carbon capture and the integration of chemical lopping in auto-thermal reforming and steam reforming [9].

With the increased funding and attention that chemical looping was receiving, Chalmers university successfully operated a unit for over 1000 hours [10], successfully testing a large CLR unit under conditions like those seen in industry [11]. Feasibility study and simulation was done on a 3 MWe unit [12] and large scale testing demonstrations was done on 455 MWe commercial unit  [13], [14], [15]. 

By 2010 chemical looping processes had achieved more than 3500 hours of continuous operation and a significant number of papers, and patents in the space of 10 years, with testing of 36 different oxygen carrier materials [16].

Chemical Looping In a Packed Bed

A packed bed chemical looping reactor consists of the oxygen carrier particles packed into the reactor with alternating gas feed to the reactor (Figure 1.4). Noorman et al. [17] showed the feasibility of chemical looping using a packed bed reactor, shifting from the fluidised bed and bubbling bed reactors used for chemical looping previously [18]. 

Chemical looping performed in a packed bed reactor conventionally has three stages. The first stage is oxidation in air, producing hot oxygen-depleted air (N₂), which is used for power generation by being fed to a turbine. The next stage is where the oxidised oxygen carrier is reduced using a low-grade fuel, producing CO₂ and H₂O we can be easily separated for CO₂ sequestration. The third stage involves a heat removal stage, but this is dependent on the oxygen carrier being used [19], [20].

The benefit of using a packed bed reactor compared to using a fluidised bed is the difficulty associated with the separation of gases and particles is avoided and full utilisation of oxygen carrier oxidation states [17]. 

The flexibility of the types of chemical looping process in a packed bed reactor has been demonstrated with dry, wet and steam reforming compositions with the process having a dependence on the oxygen carrier used, with high material stability and reactivity being required [20]. 

When operating a PBR for chemical looping, two different velocities must be taken into account; these are the heat front and reaction front (Figure 1.5). The heat front involves the thermal motion of particles, with a velocity slower than the reaction front, with heat transfer occurring when the oxygen carrier is cooled down to the gas inlet temperature. The reaction front is the thin area between separating the hot products from the cool reactants that determines the gas-solid conversion and the heat generated in the bed [19], [21]. 

When significant flow rates go through the reactor, the heat front velocity is greater than the reaction front velocity. The initial solid temperature isn’t affected by the maximum reactor temperature [21].  

Chemical Looping Reforming

Recently, there has been a widening of this focus onto hydrogen production and other chemicals using chemical looping reforming (Figure 1.6) due to its ability of inherent separation producing a pure product coupled with carbon capture [22]. This is the case of syngas for methanol, ammonia and also liquid fuels.

Mattisson et al. [23]  first proposed chemical looping reforming (CLR) in 2001. CLR utilises the same basic principles as CLC, with the difference being the partial oxidation of hydrocarbon fuel to form reformate syngas. H₂O is used to increase the H₂/CO ratio desired for a process like Fischer Tropsch, which requires an H₂/CO ratio of 2 [24]. 

The reformate syngas produced can be put through other processes to produce chemicals such as; H₂, CH₃OH, NH₃, Fischer Tropsch processes. There are variations of CLR depending on the desired; these include steam reforming integrated with chemical looping combustion (SR-CLC), autothermal chemical looping reforming (CLR-A) and chemical looping steam methane reforming (CL-SMR).

Steam reforming integrated with chemical looping combustion

SR-CLC is a syngas generation process that Rydén and Lyngfelt [25] proposed. SR-CLC involves the conversion of steam and hydrocarbons, which is the same as conventional steam reforming. The CLC element is there to provide a source of heat for the endothermic reactions [16].

The reactor configuration used in SR-CLC consists of an air reactor for oxidation of the oxygen carrier and a fuel reactor to reduce the oxygen carrier using a fuel. The reforming stages consist of a series of tubes operated at elevated pressures and packed with the oxygen carrier. The reforming tubs are immersed within the fuel reactor (Figure 1.7), and during the reduction with the hot oxygen carrier, heat is transferred to the tubes for the reforming to occur [26], [27]. 

The position of the reforming tubes is due to the favourable conditions for heat transfer, with the hot particles easily maintaining a good tube wall temperature profile [16], [25]. Furthermore, favourable heat-transfer conditions have improved H₂ selectivity compared to conventional SMR [25].

Producing pure H₂ from SR-CLC requires integrating Water-Gas Shift (WGS) and Pressure Swing Adsorption (PSA), providing 100% carbon capture, which involves separating H₂O from CO_2, which is a simple process compared to the costly and energy-intensive carbon capture used in conventional SMR.  

Issues present with SR-CLC are due to the possible degradation of the reforming tubes due to high temperatures, leading to cracks forming and loss of containment of the oxygen carrier into the air or fuel reactor [27]. Furthermore, the costs increase due to the requirement of WGS and PSA units, H₂ production. Reduction of these costs would be necessary to generate H₂ at a competitive price point. Otherwise, SR-CLC would be a better syngas production process. 

Chemical looping autothermal reforming

H₂ generation using CLR-A requires WGS and PSA units to maximise H₂ from the syngas. CLR-A produces H₂ without an external heat supply, removing the CO₂ emissions caused by external combustion for heat supply [26]. The significant advantage of CLR-A is that the heat needed to convert the hydrocarbon fuel into syngas doesn’t involve costly O₂ production and without any mixing of air with carbon-based fuels [28] (Figure 1.8). 

The heat balance is essential for CLR-A, with the heat generated from the exothermic oxidation of the oxygen carrier using air having to be sufficient enough to satisfy the heat required for the endothermic reduction and reforming stages [26], [28]. 

Other advantages of CLR-A are; less H₂O and oxygen carrier are required per unit fuel feed, no NO_X formation and produces syngas that can be used in methanol production and Fischer Tropsch, that isn’t possible with steam reforming of CH₄ and reduced sulphur poisoning of oxygen carrier [29], [30].

Chemical looping steam methane reforming

CL-SMR is a process that produces pure H₂ and syngas separately. Like other forms of chemical looping, the oxygen carrier is partially reduced by methane in the fuel reactor producing syngas. The next step is the difference with steam being used to oxidise the oxygen carrier to produce pure H₂. An air reactor is sometimes included to recover the oxygen carrier due to steam not fully recovering the lattice oxygen entirely as it is a weak oxidising agent (Figure 1.9) [28]. 

CL-SMR is an attractive option due to the possibilities of producing H₂ and syngas without the need for WGS or PSA units which reduces costs. The oxygen carrier must show high levels of reactivity with both CH₄ and H₂O throughout many cycles and must be resistant to carbon deposition, which can reduce the materials performance and carbon particles reacting the H₂O leading to contamination of the H₂ produced. The current literature is looking at ways to optimise the performance of oxygen carriers (Fe-based, Ni-based, Cu-based etc.) to find a suitable material to be used in CL-SMR [31]. The case (a) is not thermally balanced while case (b) it is because the presence of air is providing heat to the system.

References

• [1] A. Tong, M. V. Kathe, D. Wang, and L.-S. Fan, Handbook of Chemical Looping Technology. 2017. doi: 10.1002/9783527809332.
• [2] K. W. Lewis and E. R. Gilliland, ‘Production of pure carbon dioxide’, 1954
• [3] H. J. Richter and K. F. Knoche, ‘Reversibility of Combustion Processes’, in Efficiency and Costing, 1983. doi: 10.1021/bk-1983-0235.ch003.
• [4] M. Ishida, D. Zheng, and T. Akehata, ‘Evaluation of a chemical-looping-combustion power-generation system by graphic exergy analysis’, Energy, vol. 12, no. 2, 1987, doi: 10.1016/0360-5442(87)90119-8.
• [5] M. Ishida and H. Jin, ‘A new advanced power-generation system using chemical-looping combustion’, Energy, vol. 19, no. 4, 1994, doi: 10.1016/0360-5442(94)90120-1.
• [6] S. Abuelgasim, W. Wang, and A. Abdalazeez, ‘A brief review for chemical looping combustion as a promising CO2 capture technology: Fundamentals and progress’, Science of The Total Environment, vol. 764, Apr. 2021, doi: 10.1016/j.scitotenv.2020.142892.
• [7] A. Lyngfelt, B. Kronberger, J. Adanez, J. X. Morin, and P. Hurst, ‘The grace project: Development of oxygen carrier particles for chemical-looping combustion. Design and operation of a 10 kW chemical-looping combustor’, in Greenhouse Gas Control Technologies, 2005. doi: 10.1016/B978-008044704-9/50013-6.
• [8] J. X. Morin and C. Béal, ‘Chemical Looping Combustion of Refinery Fuel Gas with CO2 Capture’, in Carbon Dioxide Capture for Storage in Deep Geologic Formations, 2005. doi: 10.1016/B978-008044570-0/50123-9.
• [9] M. Rydén et al., ‘Developing chemical-looping steam reforming and chemical-looping autothermal reforming’, in Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO2 Capture Project, First Edit., vol. 3, Cplpress, 2009, ch. 14, pp. 181–200.
• [10] C. Linderholm et al., Chemical looping combustion with natural gas using spray-dried NiO-based oxygen carriers, vol. 3. 2009.
• [11] M. Rydén et al., ‘Developing chemical-looping steam reforming and chemical-looping autothermal reforming’, in Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO2 Capture Project, First Edit., vol. 3, Cplpress, 2009, ch. 14, pp. 181–200.
• [12] N. Berguerand and A. Lyngfelt, ‘The use of petroleum coke as fuel in a 10 kWth chemical-looping combustor’, International Journal of Greenhouse Gas Control, vol. 2, no. 2, 2008, doi: 10.1016/j.ijggc.2007.12.004.
• [13] C. Béal et al., ‘Development of Metal Oxides Chemical Looping Process for Coal-Fired Power Plants’, Darmstadt: 2nd International Conference on Chemical Looping, Sep. 2012.
• [14] L. Zeng et al., ‘Coal Direct Chemical Looping Retrofit to Pulverized Coal Power Plants for In-Situ CO2 Capture’, Columbus, 2013.
• [15] H. E. Andrus, Jr., J. H. Chiu, C. D. Edberg, P. R. Thibeault, and D. G. Turek, ‘Alstom’s Chemical Looping Combustion Prototype for CO2 Capture from Existing Pulverized Coal-Fired Power Plants’, Pittsburgh, PA, and Morgantown, WV (United States), Sep. 2012. doi: 10.2172/1113766.
• [16] J. Adanez, A. Abad, F. Garcia-Labiano, P. Gayan, and L. F. De Diego, ‘Progress in chemical-looping combustion and reforming technologies’, 2012. doi: 10.1016/j.pecs.2011.09.001.
• [17] S. Noorman, M. van Sint Annaland, and Kuipers, ‘Packed Bed Reactor Technology for Chemical-Looping Combustion’, Industrial & Engineering Chemistry Research, vol. 46, no. 12, Jun. 2007, doi: 10.1021/ie061178i.
• [18] R. Ocone, ‘Transport phenomena in packed bed reactor technology for chemical looping combustion’, Chemical Engineering Research and Design, vol. 90, no. 10, Oct. 2012, doi: 10.1016/j.cherd.2012.02.012.
• [19] V. Spallina, F. Gallucci, and M. van Sint Annaland, ‘Chemical Looping Processes Using Packed Bed Reactors’, in Handbook of Chemical Looping Technology, 2018. doi: 10.1002/9783527809332.ch3.
• [20] V. Spallina, B. Marinello, F. Gallucci, M. C. Romano, and M. Van Sint Annaland, ‘Chemical looping reforming in packed-bed reactors: Modelling, experimental validation and large-scale reactor design’, Fuel Processing Technology, vol. 156, 2017, doi: 10.1016/j.fuproc.2016.10.014.
• [21] R. Gort and J. J. H. Brouwers, ‘Theoretical analysis of the propagation of a reaction front in a packed bed’, Combustion and Flame, vol. 124, no. 1–2, 2001, doi: 10.1016/S0010-2180(00)00149-8.
• [22] X. Zhu, Q. Imtiaz, F. Donat, C. R. Müller, and F. Li, ‘Chemical looping beyond combustion-a perspective’, 2020. doi: 10.1039/c9ee03793d.
• [23] T. Mattisson and A. Lyngfelt, ‘Applications of chemical-looping combustion with capture of CO2’, in Second nordic minisymposium on carbon dioxide capture and storage, 2001.
• [24] C. Allevi and G. Collodi, ‘Hydrogen production in IGCC systems’, in Integrated Gasification Combined Cycle (IGCC) Technologies, Elsevier, 2017. doi: 10.1016/B978-0-08-100167-7.00012-3.
• [25] M. Rydén and Lyngfelt. A, ‘Using steam reforming to produce hydrogen with carbon dioxide capture by chemical-looping combustion’, Int J Hydrogen Energy, vol. 31, no. 10, Aug. 2006, doi: 10.1016/j.ijhydene.2005.12.003.
• [26] M. Luo et al., ‘Review of hydrogen production using chemical-looping technology’, 2018. doi: 10.1016/j.rser.2017.07.007.
• [27] M. R. Rahimpour, M. Hesami, M. Saidi, A. Jahanmiri, M. Farniaei, and M. Abbasi, ‘Methane Steam Reforming Thermally Coupled with Fuel Combustion: Application of Chemical Looping Concept as a Novel Technology’, Energy & Fuels, vol. 27, no. 4, Apr. 2013, doi: 10.1021/ef400026k.
• [28] M. Ortiz, A. Abad, L. F. de Diego, P. Gayán, F. García-Labiano, and J. Adánez, ‘Optimization of a chemical-looping auto-thermal reforming system working with a Ni-based oxygen-carrier’, Energy Procedia, vol. 4, 2011, doi: 10.1016/j.egypro.2011.01.071.
• [29] H. RYU, G. JIN, and C. YI, ‘Demonstration of inherent CO2 separation and no NOx emission in a 50kW chemical-looping combustorContinuous reduction and oxidation experiment’, in Greenhouse Gas Control Technologies 7, Elsevier, 2005. doi: 10.1016/B978-008044704-9/50238-X.
• [30] F. García-Labiano, L. F. de Diego, P. Gayán, J. Adánez, A. Abad, and C. Dueso, ‘Effect of Fuel Gas Composition in Chemical-Looping Combustion with Ni-Based Oxygen Carriers. 1. Fate of Sulfur’, Ind Eng Chem Res, vol. 48, no. 5, Mar. 2009, doi: 10.1021/ie801332z.
• [31] M. H. S. Garai, M. R. Khosravi-Nikou, and A. Shariati, ‘Chemical Looping Steam Methane Reforming via Ni‐ferrite Supported on Cerium and Zirconium Oxides’, Chem Eng Technol, vol. 43, no. 9, Sep. 2020, doi: 10.1002/ceat.202000054.

Dr. Adam Zaidi

Dr. Adam Zaidi, PhD, is a researcher at The University of Manchester (UK). His doctoral research focuses on reducing carbon dioxide emissions in hydrogen production processes. Adam’s expertise includes process scale-up and material development.’

The post Fe-Based Chemical Looping | Upgrading Steam-Iron for Efficient Ammonia & Hydrogen Production with CO₂ Capture appeared first on Engineeringness.

1. Seperation Process Principles, 3rd Edition by J. D. Seader, Ernest J. Henley and D. Keith Roper

Seader et al have provided one of the most comprehensive books on separation processes within the chemical and biochemical industry. This book covers the fundamental concepts of separation processes and provides advanced concepts that help solve world problems in energy, environmental, and health areas.

Topics covered:

• Separations by phase addition or creation
• Separations by barriers and solid agents
• Separations that involve a solid phase
• Mechanical separation of phases

Some of the features included in the 3^rd edition are study questions at the end of each chapter to ensure key points were learnt, more examples and exercises with their solution, and increased clarity of exposition. The 3^rd edition also includes bioseparation within its chapters from D. Keith Roper who has extensive industrial and academic experience in bioseparation.

Learn More or Buy Here

2. Solid – Liquid Seperation, 4th Edition by Ladislav Svarovsky

This book contains all the important industrial processes used in the recovery of solids and the purification of liquids, most process industries use a form of solid-liquid separation and Svarovsky had felt higher education do not cover this well, hence, this book was made. It is intended for graduate engineers and scientists who have a keen in design and production for research and development.

Topics include:

• Coagulation and flocculation
• Gravity Thickening
• Hydrocyclones
• Separation by centrifugal sedimentation
• Screening; Filtration Fundamentals
• Filter aids
• Deep bed filtration
• Pressure filtration
• Vacuum filtration
• Centrifugal filtration
• Counter-current washing
• Cake washing
• Filter media
• Flotation
• Selection
• Membrane Separation
• High gradient
• Particle fluid interaction

Readers can indulge in the up-to-date principles and industrial practice of solid-liquid separation and washing techniques from someone who is in top of their field.

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3. Seperation Process Engineering: Includes Mass Transfer Analysis, 3rd Edition by Phillip C. Wankat

This book is one of the most accessible guides available on modern separation processes, Phillip C. Wankat provides key separation processes concepts with the use of simulation practice, spreadsheet-based exercises using real data.

Topics covered:

• Liquid-liquid extraction
• Adsorption
• Chromatography
• Membrane separations, including gas permeation, reverse osmosis, ultrafiltration, pervaporation, and applications

The 3^rd edition includes an updated chapter, including equilibrium, chemical purity, crystal size distribution, and pharmaceutical applications. As well as new mass transfer analysis sections on numerical solutions for variable diffusivity. Recommended for those in either industry or academia.

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4. Industrial Seperation Processes: Fundamentals, by Andre B. de Haan, Hans Bosch

This book is great for those of you who are graduates, this textbook was created to provide an overview of fundamental principles that are used frequently within industrial separation methods. Haan and Bosch focus on both the computational method and physical principles to access the techno-economic feasibility of the various separation methods.

Topics covered:

• Characteristics of Separation Processes
• Evaporation and Distillation
• Absorption and Stripping
• General Design of Gas/Liquid Contactors
• Liquid-Liquid Extraction
• Adsorption and Ion Exchange
• Drying of Solids
• Crystallization and Precipitation
• Sedimentation and Settling
• Filtration
• Membrane Filtration
• Separation Method Selection

Each chapter contains a condensed section overviewing the most common equipment used in industry as well as exercises and solutions to test the principles learnt.

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Adrian Michaels

Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).

The post The 4 Most Important Separation Process Books For Chemical Engineers appeared first on Engineeringness.

What Is HETP and HTU and Their Importance in Separation Processes

In the realm of chemical engineering, the efficiency of separation processes is pivotal to optimizing production and ensuring quality. Height Equivalent to a Theoretical Plate (HETP) and Height of a Transfer Unit (HTU) are two critical metrics used to gauge this efficiency. HETP is a measure that reflects the performance of a separation column, indicating the column length required to achieve a level of separation equivalent to one theoretical plate. On the other hand, HTU assesses the height of the packing in a column needed for a solute to have its concentration changed by a specified amount, a concept vital for understanding mass transfer within the column.

HETP Method 

The Height Equivalent to a Theoretical Plate (HETP) method is a concept in chemical engineering and separation processes, HETP is a measure of the efficiency of a packed columns used in distillation or gas absorption ; it represents the height of the column that is required to achieve a separation equivalent to one theoretical stage or plate.

In distillation, a theoretical plate is an imaginary zone or stage in which two phases, such as vapor and liquid, establish an equilibrium with each other. The more theoretical plates a column has, the more efficient the separation, because each plate represents a single step of equilibrium and hence a further degree of purification.

How To Calculate HETP

The HETP is calculated by dividing the total height of packed section by the number of theoretical plates (N):

The lower the HETP, the more efficient the column is, because it means that less height is needed for each theoretical stage of separation. This value is influenced by many factors, including the physical properties of the substances being separated, the column’s design, the packing material within the column, and the operating conditions.

HTU Method 

The HTU (Height of a Transfer Unit) method is another measure used in the engineering of separation processes such as distillation, absorption, and stripping. While HETP relates to the number of theoretical plates or stages, HTU pertains to the actual physical height of the packed section of a column required to achieve a certain degree of mass or heat transfer.

The concept of HTU is particularly useful when dealing with packed columns rather than tray columns. It provides a measure of the column’s efficiency in terms of the height needed to achieve the equivalent of one transfer unit of operation. 

How To Calculate HTU

The HTU is determined by the following relationship:

where:

• H – is the total height of the packed section of the column.
• N_t – is the number of transfer units, which is a dimensionless number representing the difficulty of the separation process.

To calculate the HTU, you also need to know the driving force for the transfer process, which could be a concentration difference for mass transfer or a temperature difference for heat transfer.

Industrial Applications of HETP and HTU

In industrial applications, the concepts of HETP and HTU are not mere theoretical constructs but are integral to the operational excellence of separation processes. Case studies in sectors like petrochemical refining and pharmaceuticals illustrate the real-world applications of these metrics. For instance, a petrochemical plant may use HETP values to optimize the design of a distillation tower, leading to a significant reduction in energy consumption and enhanced purity of the final product. Similarly, HTU metrics have been employed in the pharmaceutical industry to refine the chromatography processes, ensuring the precise separation necessary for drug purity and efficacy. These case studies demonstrate that attention to HETP and HTU can lead to tangible improvements, such as cost savings, increased yield, and environmental benefits. The lessons learned show importance of these measurements in process optimisation and innovation within the chemical engineering field.

How To Choose Between HETP and HTU

In practical terms, HETP, based on theoretical plates, is more intuitive and easier to conceptualise , making it useful in comparative analysis and design of columns. However, it’s idealised and can inconsistent across different operating conditions. HTU, which measures the actual height of packing needed for mass transfer, provides a more detailed and realistic assessment. It’s more complex to calculate and less intuitive but offers a deeper understanding of the separation process in packed columns.

Adrian Michaels

Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).

The post Analysis of Methods to Calculate Efficiency in Packed Columns: HETP and HTU appeared first on Engineeringness.

Nano-filtration is a modern membrane filtration technique primarily applied to water with low total dissolved solids, like surface and fresh groundwater, aiming to soften it by removing multivalent ions and to eliminate by-products such as natural and synthetic organic materials.

Applications Of Nano-Filtration In Industry

Increasingly, nano-filtration finds its use in the food industry, for the dual purposes of concentration and selective demineralisation of monovalent ions. This process utilises membranes with nanoscale pores, typically ranging from 1 to 10 nanometers, falling between micro-filtration and ultrafiltration in terms of pore size, and slightly larger than reverse osmosis pores. These membranes are usually crafted from polymer thin films, with common materials including polyethylene terephthalate and various metals. The precise control of pore size is achieved by manipulating the pH, temperature, and development time, allowing for pore densities between 1 and 1 million pores per square centimetre.

Traditionally, the primary application of nanofiltration in water treatment has been for softening purposes. This is achieved by its ability to selectively filter out divalent ions, while permitting smaller monovalent ions to pass. This contrasts with ion exchange processes, which typically add sodium ions to the water. Nanofiltration, therefore, offers the advantage of softening water without the introduction of additional elements.

Nano-Filtration Advantages

Nanofiltration’s advantages over centrifugation include its higher precision in filtration, particularly in selective removal of solutes. This makes it suitable for applications requiring detailed separation at the molecular level. Nanofiltration’s membrane-based process allows it to treat a wider range of substances compared to centrifugation, which is limited to separation based on density and size. In agro-industrial applications, nanofiltration efficiently handles waste streams, a task where centrifugation might not be as effective. Moreover, nano-filtration systems can be optimised for energy efficiency and tailored to specific industry requirements, offering operational flexibility.

Reverse osmosis, known for its finer filtration capabilities, can remove almost all particles and contaminants, resulting in nearly pure water. However, it also strips out essential minerals like calcium, magnesium, and potassium, which have known health benefits. Some reverse osmosis systems address this by incorporating a remineralization step.

While reverse osmosis offers a higher level of purification, nano-filtration operates at slightly lower pressures, leading to potential energy savings. Nano-filtration is particularly effective at removing harmful organic substances, including pesticides, without completely stripping the water of beneficial minerals. This selective filtration is advantageous for maintaining the taste and nutritional value of drinking water.

Despite its benefits, nanofiltration is not as commonly employed in industrial membrane filtration, reserved for specific scenarios where pore size specifications fall into its narrow operational range.

Adrian Michaels

Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).

The post Revolutionising Filtration | Nano-filtration’s Emergence as a Key Technology in Water Treatment appeared first on Engineeringness.

– Vibrating feeder design plays a crucial role in various industries.
– Understanding the principles of vibrating feeder design is essential for optimal performance.
– Factors such as material properties, feeder capacity, and operational requirements influence the design process.
– Proper maintenance and troubleshooting are necessary to ensure the longevity and efficiency of vibrating feeders.
– Advances in technology have led to the development of innovative vibrating feeder designs.

Introduction

Vibrating feeders are widely used in industries such as mining, construction, and manufacturing to transport and feed bulk materials. The design of vibrating feeders is crucial for ensuring efficient and reliable operation. This article explores the key aspects of vibrating feeder design, including principles, factors influencing design, maintenance, troubleshooting, and technological advancements.

Principles of Vibrating Feeder Design

Vibrating feeders operate based on the principle of electromagnetic vibration. An electromagnetic drive unit generates vibrations that transfer energy to the material being fed. The design of the feeder must consider factors such as the amplitude, frequency, and direction of vibrations to ensure proper material flow and prevent clogging or spillage.

Material Properties and Feeder Capacity

The design of a vibrating feeder must take into account the properties of the material being handled. Factors such as particle size, density, moisture content, and flowability influence the feeder’s capacity and design parameters. Understanding these material properties is crucial for selecting the appropriate feeder type and size.

Operational Requirements

The operational requirements of the application also play a significant role in vibrating feeder design. Factors such as required feed rate, feeding accuracy, and environmental conditions need to be considered. For example, in industries where precise feeding is critical, the feeder design may incorporate features such as adjustable feed rates and control systems.

Maintenance and Troubleshooting

Proper maintenance is essential for the longevity and efficiency of vibrating feeders. Regular inspection, cleaning, and lubrication of components help prevent wear and ensure smooth operation. Additionally, troubleshooting techniques such as vibration analysis and visual inspection can help identify and resolve issues such as misalignment, loose connections, or worn-out parts.

Common Issues and Solutions

Some common issues that may arise with vibrating feeders include material buildup, excessive noise, and erratic feeding. These issues can be addressed through measures such as installing anti-stick coatings, adjusting the feeder’s amplitude and frequency, and ensuring proper alignment of components. Regular monitoring and prompt troubleshooting can help prevent major problems and minimize downtime.

Technological Advancements in Vibrating Feeder Design

Advances in technology have led to the development of innovative vibrating feeder designs. For example, the integration of sensors and automation systems allows for real-time monitoring and control of feeders, optimizing their performance and reducing human intervention. Additionally, the use of advanced materials and manufacturing techniques enhances the durability and efficiency of vibrating feeders.

Application-Specific Designs

In recent years, vibrating feeder designs have become more tailored to specific applications. For instance, in the food industry, hygienic designs with easy-to-clean surfaces and FDA-approved materials are preferred. In the mining industry, heavy-duty feeders capable of handling large volumes and abrasive materials are in demand. These application-specific designs ensure optimal performance and meet industry standards.

Conclusion

Vibrating feeder design is a critical aspect of various industries, ensuring efficient and reliable material handling. Understanding the principles, considering factors such as material properties and operational requirements, and implementing proper maintenance and troubleshooting techniques are essential for optimal performance. Technological advancements continue to drive innovation in vibrating feeder design, leading to more efficient and application-specific solutions.

Adrian Michaels

Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).

The post Principles and Design of Vibrating Feeders appeared first on Engineeringness.

– A screening machine is a versatile tool used in various industries to separate and classify materials.
– There are different types of screening machines available, including vibrating screens, trommel screens, and gyratory screens.
– The selection of a screening machine depends on factors such as the material being screened, desired output, and operational requirements.
– Proper maintenance and regular inspections are essential to ensure the efficient and reliable operation of screening machines.
– Advancements in technology have led to the development of automated screening machines that offer higher productivity and accuracy.

Introduction

Screening machines play a crucial role in numerous industries, ranging from mining and construction to food processing and recycling. These machines are designed to separate and classify materials based on their size, shape, and composition. By efficiently separating different materials, screening machines help improve productivity, reduce waste, and ensure the quality of the final product. In this article, we will explore the world of screening machines, their types, applications, and the key factors to consider when selecting one for a specific operation.

The Importance of Screening Machines

Screening machines are essential tools in industries where the separation and classification of materials are required. They are used to remove unwanted particles, separate different sizes of materials, and ensure the quality and consistency of the final product. Without screening machines, industries would face challenges in achieving desired product specifications, leading to inefficiencies and potential quality issues.

Types of Screening Machines

1. Vibrating Screens: Vibrating screens are the most common type of screening machine. They consist of a vibrating deck with different-sized screens, which vibrate to separate materials based on their size. Vibrating screens are versatile and can handle a wide range of materials, making them suitable for various industries.

2. Trommel Screens: Trommel screens are cylindrical-shaped machines with a rotating drum. As materials enter the drum, smaller particles pass through the screen, while larger particles are retained and discharged at the end. Trommel screens are commonly used in mining and recycling applications.

3. Gyratory Screens: Gyratory screens utilize a gyratory motion to separate materials. They consist of multiple decks with screens of different sizes, allowing for efficient classification of materials. Gyratory screens are often used in industries where high throughput and accurate separation are required.

Factors to Consider When Selecting a Screening Machine

1. Material Properties: The characteristics of the material being screened, such as particle size, shape, and moisture content, play a crucial role in selecting the appropriate screening machine. Different materials may require specific screen designs and configurations to achieve optimal separation.

2. Desired Output: The desired output or production rate is another important factor to consider. Screening machines have different capacities and throughput capabilities. It is essential to choose a machine that can handle the required volume of material efficiently.

3. Operational Requirements: Considerations such as space availability, power requirements, and maintenance needs should be taken into account when selecting a screening machine. It is important to choose a machine that fits within the operational constraints and can be easily maintained and serviced.

Maintenance and Inspection

Regular maintenance and inspections are crucial for the efficient and reliable operation of screening machines. Some key maintenance tasks include lubrication of bearings, inspection and replacement of worn-out screens, and cleaning of the machine to prevent material buildup. By following a proactive maintenance schedule, operators can minimize downtime and extend the lifespan of their screening machines.

Advancements in Screening Technology

Advancements in technology have led to the development of automated screening machines that offer higher productivity and accuracy. These machines incorporate features such as remote monitoring, self-cleaning screens, and intelligent control systems. Automated screening machines not only improve efficiency but also reduce the need for manual intervention, making them ideal for industries seeking to optimize their screening processes.

The Future of Screening Machines

As industries continue to evolve, so will the technology and capabilities of screening machines. The future holds the promise of even more advanced and efficient screening machines, capable of handling larger volumes of material, providing higher accuracy, and integrating seamlessly into automated production lines. These advancements will further enhance productivity, reduce costs, and contribute to the overall growth and success of industries that rely on screening machines.

Conclusion

Screening machines are indispensable tools in various industries, enabling efficient separation and classification of materials. By understanding the different types of screening machines, considering key factors during selection, and implementing proper maintenance practices, industries can optimize their screening processes and achieve desired outcomes. With advancements in technology, the future of screening machines looks promising, offering even greater productivity and accuracy. As industries continue to evolve, screening machines will remain essential for ensuring the quality and efficiency of production processes.

Adrian Michaels

Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).

The post The World of Screening Machines: Types, Applications, and Considerations appeared first on Engineeringness.

There are two main types of absorption processes: physical absorption and chemical absorption.

Physical Absorption

Physical absorption of a gas mixture will come into contact with a liquid solvent (known as the absorbent, which enters from the top of the column) wherein which some components of the gas will selectively dissolve into the liquid (known as the absorbate, which enters from the bottom of the column) via interfacial mass transfer (between boundary layers of the liquid and gas mixture).

Example: Dehydration of natural gas (absorbate) using diethylene glycol (absorbent).

Example 1:

What parameters would limit the rate of diffusion in physical absorption?

Show Answer

Chemical Absorption

Chemical absorption is similar to that of the physical absorption where a gas mixture will come in contact with a liquid solvent however, there is an additional chemical reaction between the absorbent and the absorbate.

Example: Removal of acid gases (such as carbon dioxide and hydrogen sulphide), which is a reversible reaction and can be seen in equations 1.11 and 1.12 below, respectively.

 (1.11)

(1.12)

Figure 1: Shows a schematic drawing of an absorption column used to produce nitric acid, (“Wikipedia”, 2020).

Production of nitric acid and sulphuric acid, which is an irreversible reaction and can be see seen in equations 1.13 and 1.14 below, respectively.

(1.3)

(1.14)

Example 2:

What parameters would limit the rate of diffusion in chemical absorption?

Show Answer

Types of Columns

There are two main types of columns used in industry: packed and tray column.

Packed Column

In packed columns, the absorption columns are packed with material that enhances the contact between the absorbent and absorbate, where columns can be either packed with material randomly (such as Raschig rings) or in a specified structure, this can be seen in figure 2 below.

Figure 2: Shows an illustration of a packed column, where the upper half of the column has material structurally packed and the lower half of the column is randomly packed with material, (“Buffalo Brewing Blog”, 2020).

Between the two types of packing, random packing is much less expensive in comparison to that of structured packing whilst still being able to provide efficient contact between the liquid-gas boundary. However, structured packing is one of the better ways to distribute liquid across the entire cross-sectional area of the column as the liquid is spread so thin thanks to the structure packing. This then allows for a much smaller pressure drop throughout the column in comparison to that of the randomly packed columns, which in turn provides an increase in energy efficiency, (“MACH Engineering”, 2020).

Tray Column

Trayed columns consist of plates that force the liquids to flow back and forth horizontally as it travels down the bottom of the column, whilst the gas is passed through the holes of the tray, creating contact between the two phases.

Similar to packed columns, trayed columns are used to increase the contact area between the absorbent and absorbate, however, the major benefit of trayed columns is in its use for large diameter columns and would be able to handle large operational condition ranges.

Packed vs Tray Columns

It can be seen from the table above that both types of columns have their advantages, however, when it comes to the design of columns, there are elements such as costs and sustainability of the unit operation that will help to decide which design is the best choice.

Reference

Buffalo Brewing Blog. (2020). Retrieved 1 August 2020, from https://www.buffalobrewingstl.com/pressure-drop/packedcolumn-flood-and-pressure-drop.html

Chuang, K.T. (2003). Tray Columns: Design. From https://www.semanticscholar.org/paper/Tray-Columns%3A-Design-Chuang/e207907eadf5209f2c74ded4f47c44bc35ebc85c

MACH Engineering. (2020). Retrieved 1 August 2020, from https://www.machengineering.com/random-packing-vs-structured-packing/#:~:text=Random%20packing%20uses%20a%20random,into%20a%20specific%2C%20fixed%20shape.

Richardson, J.F. Harker, J.H. Backhurst, J.R.. (2002). Coulson and Richardson’s Chemical EngineeringVolume 2 – Particle Technology and Separation Processes (5th Edition) – 12.1 Introduction. (pp.          656). Elsevier. Retrieved from https://app.knovel.com/hotlink/pdf/id:kt007FRVT3/coulson-richardsons chemical/absorption-introduction

Wikipedia. (2020). Retrieved 1 August 2020, from https://en.wikipedia.org/wiki/File:Simplified_absorption_column.png.

Adrian Michaels

Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).

The post A Brief Introduction Into The Theory Of Absorption appeared first on Engineeringness.