Natural Gas Combustion Systems and Modern Automation
Edge devices and controllers, enhanced by software solutions, offer improved functionality and control.
Natural gas combustion systems, when combined with human error, can lead to disastrous consequences and millions of dollars’ worth of property damage. Unnoticed gas leaks and problems related to inefficient combustion systems also have the potential to accumulate over the years and ultimately impact the wider global population and contribute to climate change. For these reasons, there is an increasing requirement to improve training, increase combustion efficiency and detect and prevent leaks.
However, modern workforce trends are making it difficult for companies to retain critical combustion know-how and equipment understanding over time, as indicated by the following excerpt from “Ensuring the Safety of Industrial Combustion Systems,” found in the May 2019 issue of Process Heating.
“As Baby Boomers near retirement, industrial companies must deal with an aging workforce and the need to retain and replace tribal knowledge of production processes. New employees lack familiarity with common combustion equipment. This situation is exacerbated by the on-average higher-turnover rate of millennial-age workers.”
Can Modern Automation Devices Address These Issues?
One possible option is to leverage the recent changes to the NFPA 86 standard, which now allows modern safety PLCs (rated to SIL2) to perform both the burner safeguard operation as well as process control. The promise of these all-in-one units enables more data to be captured, analyzed and potentially used for predictive maintenance. This control philosophy enables the users of the equipment to enhance their plant environment, making process heating and related operations safer.
An alternative to this is to return to the traditional separation between the combustion-safeguard system and the control system.
Modern edge-connected control devices — enhanced by software solutions — transform the traditional approach. These devices reduce the overall complexity and enable a more vendor-agnostic situation with regard to the combustion-safeguard system and controls.
Trends for process and temperature control include edge devices such as DIN-rail-mounted precision temperature controllers incorporating embedded Ethernet with robust cybersecurity capabilities.
Controller Trends for Temperature Control and Combustion Efficiency
One trend is for edge devices such as DIN-rail-mounted precision temperature controllers to incorporate embedded Ethernet with robust cybersecurity capabilities. These devices do not require extensive programming to set up PID loops or autotune. They often come with specialized functions (e.g., program recipes) and algorithms (e.g., zirconia/probes) for furnaces and ovens. They have been designed for thermal stability and to enable consistent control over long periods without calibration drift. This approach ultimately improves the efficiency of the control/combustion system over time.
Modern devices have improved sample rates of up to 50 ms and allow multiple PID settings for different operating ranges. Other features include improved overshoot and valve-positioning algorithms for use with legacy or modern gas-valve actuators.
Power-Monitoring Solution Capabilities
- Detect abnormal conditions that could represent a risk to safety and operations.
- Identify energy-event patterns to avoid or mitigate future occurrences.
- Analyze the aging of components to avoid failures and enable proactive maintenance.
- Track system capacity to prevent overloads.
- Use trending and energy modeling to identify abnormal usage of energy and other utilities (wages).
- Reveal unused system capacity to avoid upgrading or overbuilding.
- Align with energy efficiency and green building standards (e.g., ISO50001/2, SEP, LEED, NABERS).
Valve-positioning control used for three-step motorized valve actuators is driven with digital raise and lower signals. A typical example is a valve modulating the firing rate of a gas-fired furnace or oven. Some valves are already fitted with positioners; in that case, the algorithms are not suitable, and PID should be used.
Some programmable controllers contain the boundless or unbounded algorithm that does not require a feedback potentiometer. This type of valve has an inherent travel time; that is, the time needed to slew from end-stop to end-stop. This time should be measured as accurately as possible in both directions, and the average should entered into the appropriate travel-time parameter.
Valve Positioner Boundless Algorithm. The valve positioner boundless (VPU) algorithm operates without knowledge of the actual valve position. Therefore, it does not require a potentiometer on the valve. The valve positioner boundless contains a special, incremental form of the PID algorithm. It uses the valve itself as an accumulator to add up the increments calculated by the algorithm. Because of this formulation, it can be treated as a positional algorithm — like PID itself. It contains a simple software model of the valve, based on the entered travel time, which estimates the valve position (the working output).
Augmented technology can aid operators with procedures on how to run the furnace. It provides maintenance professionals with step-by-step details on performing maintenance on critical components.
Ethernet and Cybersecurity Architecture
The greatest enhancement to the modern plant environment is the ability for controllers and other devices to incorporate high speed Ethernet connections for ease of interconnecting supervisors, panels or PLCs. Industrial cybersecurity is certified to the stringent requirements of Achilles CRT Level 1.
This architecture is more cybersecure, which is important when leveraging connections into software platforms. This allows solutions for safer operator use and predictive maintenance solutions.
Software to Support Operators and Maintenance Specialists
Recent trade articles have indicated that oven and furnace manufacturers are starting to leverage augmented technology to aid operators with procedures on how to run the furnace. The same controls provide maintenance professionals with step-by-step details on performing maintenance on critical components.
Such applications, tailored to the specific process, improve operational efficiency with augmented reality. This enables operators to superimpose live process data, links to critical and mundane documentation, and virtual objects onto a cabinet, machine or plant via a tablet’s camera.
Historically, these systems were pre-engineered to meet a customer-specific need. The latest offerings allow for full customization by the OEM or end user to their specific requirements. There is no need for any specialist know-how in developing augmented-reality solutions.
Other software tools can be used to track maintenance checks and ensure compliance to required industry standards and tests. For example, some offer solutions to efficiently manage regulated industry compliance such as calibration requirements, exhaust stack tests and burner adjustments.
As part of the software family, each module is designed to interoperate with each other. This will ultimately mean that information related to calibration, burner adjustment and other common plant procedures will be tracked and scheduled with software tools. Workflow and instructions will be made available on the augmented operator solutions.
Software to Support Facilities and General Managers
Just as the loss of talent threatens the long-term stability of the industry, operational resources such as gas, electric, water and air are all critical to operations. Disruptions to these critical resources impact productivity and safety. Wasted energy and equipment failures affect the bottom line. Connected software provides a way to reveal hidden risks and opportunities.
Software designed to monitor power usage is purpose-built to help power-critical and energy-intensive facilities maximize uptime and operational efficiency. These tools serve as a window to the digitized utility network, taking advantage of IIoT connectivity and distributed intelligence.
In conclusion, there is an urgent need for safe plant environments, upskilled and trained process operators, efficient and advanced combustion controls, and insight and understanding of trends in gas and other critical resource usages. Modern-day automation solutions can support all the above.
Software tools can be used to track maintenance checks and ensure compliance to required industry standards and tests. For example, some controls manufacturers offer solutions to efficiently manage regulated industry compliance with calibration requirements, exhaust stack tests and burner adjustments.
All-in-one, SIL-rated devices for safety and process control are an option for advanced combustion controls and are now allowed in the latest release of the NFPA standards. Easy-to-setup edge devices and controllers:
- Offer improved functionality and control.
- Incorporate embedded Ethernet and robust cybersecurity standards.
The controls ease communication to powerful software solutions. The new augmented reality software solutions:
- Support accelerated training.
- Aid in ensuring operator adherence to procedures.
- Allow digital tracking of maintenance checks.
- Ensure tests are scheduled and on time.
- Perform energy monitoring.
- Report and alert on adverse trends in time for corrective action.
Edge controllers and related software solutions provide the building blocks to enable a safe and productive production environment.