After a year of working as a consultant with Solids Handling Technologies, I have discovered that material handling problems today are common in every industry. Previously, I worked at a waste coal power plant handling anthracitic waste (culm). I find my experiences there invaluable. The culm consisted mostly of rocks and dirt, and sat in large piles exposed to the elements. As the material gained moisture it became very difficult flowing, resulting in significant problems.
A typical day of fighting flow problems consisted of the use of sledgehammers, attempting to restore flow in a bin with air lances, and cleaning material buildup in clogged chutes. The operators and maintenance staff there gave everything they had to keep a steady stream of material feeding into an ever hungry boiler. I am honored to have worked with such incredible individuals.
Having experienced such grueling problems, I am grateful for the beauty of the science of solids flow. The science of solids flow comes from the work of Dr. Andrew Jenike in the 1950-60s. The science consists of knowing the flow properties of the material at hand, and handling it in a controlled and reliable manner. For instance, by testing the flow properties of a material, a bin can be properly designed such that arching and ratholing are eliminated.
During my first year in this field I visited several plants, handling a wide variety of solids. Interestingly, the problems I observed bear striking resemblance to those I saw at the power plant. Material handling problems are common within every industry, and by no means unique to the industry or plant I came from. Materials can be difficult flowing; this includes material buildup, uncontrolled flow stoppages, material segregation, and erratic flowability.
As a consultant it is troubling to see these pernicious problems persist. Most problems I have seen are solvable. However, I have a few thoughts why the issues remain.
First, there is a lack of knowledge of the science of bulk solids handling. Most involved with the storage and flow of solids are not aware that there is a science to the field. I worked at a plant handling over 100 tons per hour of culm, yet my formal engineering degree failed to cover any type of solids flow.
This lack of education on the science of solids handling, leads to misconceptions of how solids behave and how to alleviate problems. For instance, it is easy to believe that a solid stored in a silo will behave like a liquid in a vessel. However, this is not the case and treating a powder filled silo as such could result in quite disastrous results.
Secondly, due to financial constraints, many plants that face solids handling problems do not have the luxury of addressing these issues. These plants try their best with the tools and knowledge in their possession. This does not leave spare finances for material testing, an engineering consultant, and the necessary retrofits to fix the problem. This is particularly true, when those at the plant are unsure if their problem can be solved. Sadly, leaving solids handling problems unaddressed often results in far greater costs over the life of a plant.
Thirdly, another reason to not address material handling problems is a “get-by” philosophy. A plant may deem their material handling problems somewhat manageable. Meanwhile an outside engineering consultant, such as myself, will always want to fix the problems. Those at the plant must decide; should material handling problems be left unaddressed? Solving these problems means operators are not using sledgehammers, air cannons are not fired repeatedly, and material behaves in a way that is both predictable and reliable. The outcome can be both good and realistically achievable. Nonetheless, it is the decision of the plant owners, designers, maintenance managers, and other leaders to determine the best course of action.
Those making these decisions must understand the implications of unresolved material handling problems. When solids exhibit flow problems, it can be costly, dangerous, and demoralizing. Costs are encountered as plant production drops, additional staffing is needed, and equipment failures increase. Safety problems arise because a material is out of control, the system is not able to control or contain the material appropriately. This leads to accidents and near misses within the bulk solids world. A plant with material handling problems also creates a demoralizing work environment. Workers lose their sense of accomplishment and the ability to take pride in their work. Equipment operators might have great skill and knowledge, but what does that matter when they know most of their shift will be hammering on a bin with little to no results.
These problems are unnecessary and should be addressed because those across the various industries and what they do matters. I am still new to the world of solids handling, but I have come to understand that consultants can help. We can provide practical design solutions to those who face these difficult problems. These problems are faced by many plants in every industry handling solids. It is important to understand that there is a proven science to the storage and flow of solids. Furthermore, proper understanding, testing, design, and implementation can alleviate problems. Solving these problems matters, because the people at these plants and what they do matters.
Scott Miller is a senior consultant at Solids Handling Technologies in Fort Mill, SC. Miller works closely with clients to provide the expertise required to evaluate and solve their solids flow problems. He analyzes flow properties test data produced by our testing laboratory, and writes flow reports describing the parameters necessary to resolve flow problems. Miller is also actively involved in providing practical, conceptual design recommendations to clients. He received his Bachelor of Science degree in mechanical engineering, with a minor in mathematics from Geneva College in Beaver Falls, PA. His background as a plant engineer at a power generation facility in PA provided valuable experience handling anthracitic waste, planning outages, and providing solutions to typical coal handling problems. For more information, call 803-517-0054 or email [email protected] For more information on Solids Handling Technologies Inc., contact Joseph Marinelli at 803-802-5527 or [email protected]