The latter part of the 20th Century saw the introduction of more stringent boiler manufacturing standards, particularly in relation to welding technology and inspection, and the evolution of digital control systems that now provide an unsurpassed level of reliability. The modern, micro-processor based, high-integrity, “Boiler Control System” (BCS) has the ability to perform many of the tasks traditionally undertaken by the qualified operator allowing extended periods of automatic operation without any human intervention whatsoever. A key feature of modern packaged boilers is that they are designed to operate unsupervised for extended periods.
The degree of human supervision and operator training requirements are determined by the level of sophistication of the “Boiler Control System” (BCS). They are defined in local boiler codes and standards and differ widely between jurisdictions. For example, in some, a high-pressure boiler is defined as any boiler operating above 1 BAR (approximately 15 psig) pressure and, regardless of all other considerations, it must at all times be under the control of an appropriately qualified operator. Other jurisdictions impose capacity constraints on unsupervised operation but in many, boiler codes and other relevant legislation have been revised and extended to accommodate the demand from industry for this type of boiler.
Industrial boilers of all types generally fall into one of three categories in terms of their operational and qualification requirements. They are:
• Attended Boilers;
• Limited-Attendance Boilers;
• Unattended Boilers.
What is a “packaged boiler”?
The term “Packaged Boiler” is used to https://topenergy.com.vn/ describe a boiler that is factory built and delivered either fully assembled or, as pre-built modules that can be easily assembled on site. It is essentially a self contained unit complete with a control system and all equipment required for operation. The boiler manufacturer assumes responsibility for all components and after delivery all that is required is for it to be connected to the steam distribution system, water, fuel, and electricity supplies. Almost all small and medium sized boilers manufactured today are packaged boilers and they may be the conventional firetube or watertube type, including their derivatives or, hybrid boilers such as once-through coil and electrode boilers.
What is an attended boiler?
Until relatively recently, the vast majority of steam boilers operated in the “Attended” mode. That is, they were required to have an appropriately qualified operator on-site and in the immediate vicinity of the boiler at all times that it was operating. Since the introduction of micro-processor based technology to boilers from around 1990 onwards, many traditional attended boiler owners have upgraded their control systems. Given also that micro-processor based controls are now an almost universal feature on new packaged-boilers, the traditional boiler attendant is becoming an endangered species in small to medium sized plants supplying process steam. At the very least, their role has changed from that of direct, hands-on operation to one of supervising the operation of the BCS and performing tasks that ensure its continuing integrity and compliance with the requirements of boiler codes and standards.