Let me say this by way of introduction: these publications are for the engineer and supervisor who are responsible for small scale steam plant operations. His steam boiler fires pea coal and produces less than 30 tons of saturated steam per hour at less than 20 bar pressure. These limitations exist because of the boiler configuration – it is a chain grate fire tube boiler, consisting of one or two furnace flues.
He probably has been relying on the perceptions, impressions and coaching of his predecessors to make him fit for a very responsible position. He may even have completed boiler operators and boiler maintenance courses, but lately the boiler scene has changed dramatically in terms of cost saving demands on management, deteriorating coal qualities and more stringent environmental legislation. His training and experience is increasingly letting him down in understanding how to tackle these challenges from first principles. As a matter of fact, he may have an electrical background and inherited the boiler plant as part of a company restructure.
Don’t feel alone! If this was not quite your experience, it definitely was mine. I faced my first boiler in the dairy industry in 1983. My mentor was the regional boiler supervisor and he ran each boiler house under his supervision like a military operation. Operators were coached, not trained. They became programmed robots, with only a vague idea why they were performing the actions they were instructed to perform.
After close to 40 years in the boiler and combustion industry I have learned and experienced sufficiently much to know that my original mentor had it wrong in many respects, primarily because little of what he believed was based on sound engineering principles. After all, coal was still plentiful, cheap and of good quality in those days with little focus on the efficiency of steam production.
Even today it is not uncommon to find engineering and operating staff partially or totally ignorant of the scientific principles behind combustion, boiler efficiency and boiler control, not to mention the characteristics of coal (solid fuels) and its impact on the combustion process. And quite often the little bit they do know is based on general opinion, hear-say and their own interpretation of their experiences in absence of proper education and guidance.
Thus the intention to publish a series of Boiler Bits was born. The name I selected for these publications already implies that they will be short pieces dealing with all kinds of boiler related matters. No lengthy scientific dissertations, mathematical formulas and academic papers though; I will rather aim to explain scientific principles in a logical and easy to understand way so that everyone involved with steam plant operations will be able to grasp why their plant is and performs the way it does.
In the South African context I believe there is need for practical guidelines on understanding and practicing the firing of pea coal in horizontal packaged fire tube boilers, although most of the principles discussed herein equally apply to water tube boilers and boilers firing liquid, gaseous, biomass or pulverized coal fuels. My attempts at finding specific information regarding firing pea coal on traveling grate boilers on the internet was rather disappointing – there are lots of material dealing with fire tube boilers, and firing of pulverized and atomized (gas and oil) fuels, but it seems that pea coal firing boilers receive far less than its fair share of attention. Where pea coal is mentioned, it refers to the properties of northern hemisphere coal. Basically nothing on small fire tube chain grate stokers firing local (South African) bituminous coal.
This also convinced me that there must be a need for elementary material which provides an understanding at grass roots level of all the elements and influences making up a combustion system, how these elements interact and influence one another, as well as the steam generation process as a whole; and finally how the understanding of basic principles crystallizes out in the practice of optimized steam production, i.e. how to apply scientific principles to arrive at producing steam at the lowest total cost* per kg or ton. I hope to succeed in painting the overall combustion picture in a way that will enable readers to grasp and internalize it, and to apply it towards conserving energy, reducing pollution and protecting steam plant assets.
In my opinion many of the problems experienced in the boiler house originate much higher up in the organization, at management level. I once came across the following definitions pertaining to “management” which I consider appropriate:
- A manager is a person responsible for planning and directing the work of a group of individuals, monitoring their work, and taking corrective action when necessary.
- Management in all business and organizational activities is the act of getting people together to accomplish desired goals and objectives using available resources efficiently and effectively.
I see a lot of reference to goal setting, guidance and performance assessment above. It starts with defining a mission for steam plant operations (see Boiler Bits 4), and then developing key performance areas and key performance indicators and aligning these with the organization’s mission. I am afraid I do not see this happening on a general scale in the boiler industry; that is why I still encounter engineers in charge of steam plant operations not even knowing the monthly steam production or fuel consumption. Not that they are careless or indifferent, but:-
- Senior management does not require of them to set goals, to gather information and to manage steam plant operations towards achieving a specific performance. All that seems to matter is that the boiler house keeps on pumping out sufficient steam for production to carry on its operations.
- The means of recording, processing and communicating information is totally absent.
- Everybody in the organization has settled into a (hectic) comfort zone and they do not want the operating environment disturbed.
But enough said about management for now; my focus will be more towards the technical aspects of steam plant operations. So do expect to see a number of Boiler Bits on combustion and related topics to be published over the next number of months and probably even years.
In the mean time our readers are more than welcome to contact us. Maybe somebody wants to know more of a certain aspect of boiler operation, maybe a combustion control issue, maybe just to express a view on the value of, or the need for tutorials of this nature.
* Total cost includes more than just the cost of fuel. It also includes the cost of capital, management, maintenance, personnel, water treatment, ash removal, etc.
This post was compiled by René le Roux for Le Roux Combustion, all rights reserved.Do you want to know more about steam plant management and optimization, or boiler operation in general? Please contact us for your professional boiler automation, steam system efficiency and coal characterization needs.
Kindly note that our posts do not constitute professional advice and the comments, opinions and conclusions drawn from this post must be evaluated and implemented with discretion by our readers at their own risk.