Q: Could you briefly explain your role and your experience within the field of size reduction?
Ian Hancock, Bradley Pulverizer (IH): I am Vice President of Sales and Operations at Bradley Pulverizer. My experience started with manufacturing and installation of powders plants and bulk material handling systems, followed by extensive commissioning experience worldwide on many different applications and materials, including pendulum roller mills, ball mills, air classifiers and fertilizer acidulation plants.
My current role involves taking a potential client’s initial enquiry and guiding them to the best solution for their size reduction requirements all the way from initial enquiry to commissioning and lifetime support of their mill and/or air classifier. I lead a multi-disciplined team of engineers to achieve this.
Eddie McGee, Ajax Equipment Ltd (EM): I deal with powder and other bulk solid storage and handling issues every day, and work for a company that designs and manufactures equipment for a wide variety of applications. Users come to me with powders that have set to form lumps and are not in the expected easy flow condition their process plant demands. When compaction or caking in transit or storage forms lumps, materials can be more awkward to get out of hoppers (as they form blockages) and in to process plant like dissolvers. They can also then take a longer time to dissolve and even be a danger to the tank’s stirrer.
Simon McGhie, Lynemouth Power Station (SML): My role at Lynemouth is that of the Power Station Performance Engineer, specialising in process efficiency and process performance. The performance aspect includes milling plant and combustion optimisation, in order that boiler efficiency and stack emission performance can be maximised.
I’ve been employed in the generation industry for nearly 25 years, in operational and performance roles. This has encompassed both coal fired operations and more recently during biomass R&D work and subsequent station conversion to 100% biomass pellet fuelled operation.
Stefan Mende, NETZSCH-Feinmahltechnik GmbH (SMN): I studied Mechanical Process Engineering and did intensive investigations about grinding of materials down to the nanometer size range during my time as a PhD student in Braunschweig. Since 2004 I have been a member of the NETZSCH team, first as sales support, later as the head of the R&D and today as Manager of Technical and Scientific Communication. In this function I help customers, partners, and students around the world to find the most efficient process technologies to meet their requirements.
Q: What are the main engineering challenges and what are the most common issues you hear from colleagues?
IH: The main challenge we hear is that maintenance of powders plants is critical and expensive, so the challenge is achieving maximum up-time of the plant within budget.
EM: Product quality is always a key parameter and getting powders in the right condition, at the right time, and at the point of use, is critical to plant and product performance. However, the effects of time, temperature or moisture can result in aging, caking or compaction during storage in bags, sacks or other containers with the contents suffering unintended agglomeration into lumps which can be problematic for handling in subsequent conveyors or other processing systems.
SML: I think the main challenge within the generating industry is correlating the changes in milling performance between different biomass fuels with the fuel properties. There is lots of experience and knowledge regarding coal milling and well-developed lab tests to determine the likely ‘on plant’ performance, but this is not the case with biomass derived fuels. For example, there is no biomass equivalent of Hardgrove index, and pellet durability test values are not always reflected in how a mill will perform with any given fuel.
Understanding how the milling of biomass fuels is impacted and the variability created by fibre source, species type, region of origin, etc. has only really come to the forefront over the last 10 years or so.
SMN: Customers are looking always for the simplest, safest, most productive and efficient way to produce their materials in a reproducible quality. The challenge is not to find this process technology; the challenge is usually to understand the raw material properties and to find a clear definition of the product quality we are looking for.
Q: What will you be focusing on in your presentation?
IH: I will be focusing on air classification systems, with particular emphasis on them in a size reduction system. I will look at the options available, advantages and disadvantages, and how the correct classifier can significantly affect the overall system performance.
EM: I will be focusing on the physical characteristics of the material and will draw on applications ranging from waste handling to chemical and food processing which demand lump breaking to a consistent size to ease processing and handling. Aspects covered will include the actions of impact, crushing and shearing, with review of different designs for effective size reduction.
SML: My presentation will focus on the R&D work carried out at Lynemouth during the feasibility study stage of the conversion from coal fired operation to 100% biomass pellet. From initial concept, through the modification and trialling stages, to finally to demonstrating how a Lynemouth mill could be adapted to mill biomass pellet.
SMN: Our presentation will explain material properties and the effects of mechanical material stress. Based on the knowledge gained, conditions will be derived that are necessary for the design of an efficient, high-yield comminution process.
The focus of my part of the presentation are the material properties and the diversity of different technologies. With a real-life example from the mineral industry, it will be demonstrated how the most efficient and sufficient process technology can be selected regarding properties of the raw material, target quality of the product as well as production capacity.
Q: Are there any other speakers you are particularly interested in hearing from and if so why?
IH: I am particularly interested in Simon McGhie’s presentation on the challenges of changing a power station from coal to biomass. This is a very “now” topic and will be a great insight into an end user’s challenges and solutions.
EM: That’s a bit of an unfair question as I do know a couple of them and am really looking forward to hearing both academic and practical talks. However, others are new to me and it’s a really wide range of topics being covered so I am looking forward to it all. It’s just such an important activity from milling salt to crushing aggregate to finely milling pharmaceuticals. It touches so many aspects of our industry and our lives that it really merits the detailed review that this seminar looks to deliver.
SML: I am always interested to hear other speakers. I firmly believe that ‘everyday is a school day’, and that there is always something to learn from others. Facts which may not seem useful now may very well become very relevant in the future.
Q: What specialist technologies are you most interested in for the future?
IH: I am very interested in the latest control technologies which are helping to make size reduction systems more efficient, with less down time and predicted maintenance scheduling.
EM: Size reduction takes a heavy toll on energy use and can have unwanted side effects like excessive fines generation so optimisation techniques and perhaps a greater understanding of the properties of the materials being processed as well as development of new more efficient techniques is of enormous interest for a sustainable and effective future.
SML: The generating industry is still going through massive change, and we are amid an almost complete circle. Over a period between thirty and fifty years ago the UK generating capacity largely moved away from lots of small local power stations, and centralised capacity on large power stations strategically placed and connected to the national grid system. The closure of most of these large stations and the move towards smaller facilities such as wind farms, solar farms, woodchip plants, EFW, etc. has largely shifted the emphasis back to lots of smaller facilities.
This has created a drive to use more sustainable energy sources such as biofuels and waste, and obviously working in a biomass fuel power station is an area I am very interested in.
SMN: I am really interested in all kinds of new technologies, but developments in the last 10 years have shown that even technologies patented more than 90 year ago, like agitator bead mills still have a lot of potential for energy savings and increase in production capacities, when the operator understands the technology and the formulation.
Q: What are your top tips to help engineers make optimal choices in equipment and/or material selection?
IH: My top tip is to step back and look carefully at what you are looking to achieve and undertake lab and pilot plant testing prior to committing large sums of money to equipment that is not fit for purpose.
EM: The most important one is to consider the material being handled and processed. You must have knowledge of the material's characteristics like strength, brittleness, sensitivity to working, or indeed if heating or explosivity are considerations to reckon with. And of course, have a clear idea about what size you want to reach and how tolerant or not you might be of fines generation in the process.
SML: In 99.9% of instances, my top three tips would be to listen, listen, and listen. It’s very rare that anyone discovers or tries something new, and there is almost invariably somewhere where it has been done or tried before. There’s no benefit in trying to reinvent the wheel, and knowledge and experience from elsewhere can save a lot of time, effort, and frustration. This then leaves time and effort available to improve and not repeat.
SMN: There is one tip I give always: Ask questions! – There is never a stupid question! Try to find the right specialists and understand the requirements and the goals. I am sure the specialists from NETZSCH can help you.
Q: Why is it important for engineers to join this seminar?
IH: This seminar will give an overview of many different size reduction methods and should give anyone joining a better understanding of the available technologies and help them to understand what questions they should be asking when selecting a system.
EM: You will learn of the whole range of size reduction techniques for a wide variety of bulk solids and, more crucially perhaps, gain an understanding in selection procedure for best use, be able to weigh up the various pros and cons and be able to understand limits of application.
SML: Effective material size reduction can make or break a process, and it’s vital that engineers understand the equipment and processes which can help them achieve the objectives. This links to my answer above. There’s a wealth of knowledge and experience in size reduction and milling within the material handing sectors, and seminars such as this are an ideal opportunity for this to be shared amongst delegates, to everyone’s advantage.
SMN: If you like to improve your processes, it is not enough to buy new equipment – it is necessary to understand the materials, the products and the process technology.
The Material Size Reduction seminar will be taking place live online on 27 April 2021.
Join this seminar to:
- Gain an overview of the types of size reduction equipment and their suitability for processing different materials
- Understand the performance of material classification technology and open vs. closed loop processes to maximise the quality of the finished product
- Take part in online roundtable discussions with equipment specification experts, solution providers, and end-users from a range of industries to address specific technical challenges and network with the community
- Deepen your knowledge of the OPEX and CAPEX implications of material size reduction technology to minimise spend
- Increase the uniformity and quality of reduced material output, cutting down waste in the process
- Learn about specialist technology such as fluid energy and cryogenic mills to identify potential opportunities for investment in new equipment
To book your place, please visit www.imeche.org/materialsizereduction.