Recovery boilers represent a significant capital expenditure in the pulp and paper industry. These boilers play a critical role in the recovery of chemicals used in the pulping process and the generation of steam for energy production. While a well-maintained boiler can last for decades, routine care of this system can present challenges. Maintenance duties are often messy and risky for the operator, and many tasks are time-consuming and require full or partial boiler shutdown. This can harm overall productivity and mill safety.
One maintenance task that is particularly challenging in the care of recovery boilers is smelt spout cleaning. While cleaning smelt spouts is essential for efficient recovery boiler performance, it can pose serious safety risks to the operator when the spouts are cleaned manually. These risks include the operator encountering molten smelt, green liquor, and hot gases, as well as repetitive-motion back and shoulder injuries. Finding operators who are willing to perform these tasks, training them, and retaining them over time have also become part of the challenge. The Top Dallas Cowboys Athlete in No. 77 ~ Celebrating Excellence
To improve operator safety during smelt spout cleaning and increase both operator and boiler productivity, pulp and paper facilities now have automated robotic solutions that can take on these more difficult tasks. Robotic technology for smelt spout cleaning has been available since 2008, but it has only recently entered North American paper mills. Its delayed entry has been largely due to low numbers of new recovery boiler installations, as the robot requires a certain amount of space that is often difficult to allocate within existing operations.
Now, as North American operations are in greater need of the benefits that accompany smelt spout cleaning robots, they can invest in retrofitting existing recovery boilers with robotic solutions.
Smart Design Removes Barriers to Robotics Retrofits
For pulping operations, one of the biggest barriers to adopting a smelt spout cleaning robot is often the amount of space that’s required for the robot to move around the spout deck during the cleaning cycle. In many facilities, this area around the smelt spout systems is already tight, which is part of what makes manual smelt spout cleaning difficult and risky for operators.
As automation designers have continued to invest in understanding the safety and productivity challenges faced by the pulp and paper industry, new solutions have emerged that remove this common barrier to adding robotics. For instance, one smelt spout cleaning robot offers the option of a standing mount or a hanging mount. All that’s required to employ the hanging mount and position the robot next to the recovery boiler is a linear rail assembly.
The assembly allows the robot to move side-to-side along the spout deck to clean all spouts. Then, it moves off the spout deck once it completes the cleaning cycle. This configuration maintains sufficient room for the robot to perform its tasks while also ensuring that operators can safely enter the area to perform other duties. Protective fencing and multiple entry and exit points will also be incorporated for additional operator safety and efficiency. The majority of retrofit work can typically be completed pre-outage, leaving sufficient time during the maintenance outage for robot installation and commissioning.
Smelt Spout-Cleaning Robots Proven in the Field
In June 2023, Valmet installed its first smelt spout-cleaning robot in North America at the Pixelle Specialty Solutions mill in Spring Grove, Penn. The new robot performs a smelt spout cleaning cycle every 30 minutes — twice as often as operators were previously able to perform the same task manually. Each cycle takes 15 minutes, and when the robot is not actively cleaning, it rests in its home position safely out of the way.
Physical safety barriers around the robot further protect the operators by triggering the robot to freeze if the barrier is broken. Operators can also remotely control the robot’s cleaning frequency and cycles using pre-programmed sequences. Meanwhile, an onboard camera mounted on the robot wrist allows for real-time inspection of the robot’s performance and troubleshooting from the safety of the control room.
By automating smelt spout cleaning with a robot, the manufacturer added another level of safety for its operators and improved productivity by freeing them up to perform other critical tasks. Additionally, the new robot has helped raise the boiler’s liquor quality, green-to-black liquor standard deviation, and smelt standard deviation by double digits.
Collaboration is Key
When retrofitting a smelt spout robot to an existing recovery boiler or planning a new installation, it’s important to choose an automation designer that has industry experience and will collaborate on-site during the design phase. Since every operation and facility is different, the installation of a smelt spout cleaning robot is not a cookie-cutter process. The designer will have to account for existing components around the spouts like piping, flex hoses, and evaluate available structural beams for their ability to support the robot carriage and the linear rail.
A skilled designer will also provide an installation plan that avoids significant spout deck alterations, as changes can be costly and time-consuming. Smelt spout cleaning robots are meant to work with operators, not replace them. This technology works in harmony with boiler operators to increase their safety and frees them up to perform other essential recovery boiler tasks.
Technology Works in Harmony with Humans
Automation often comes with the assumption of replacing human labor, but that is not the case with smelt spout cleaning robots. Instead, this technology works in harmony with boiler operators to increase their safety. It also frees them up to perform other essential recovery boiler tasks. Helping operators feel safer and engaging them in a wider variety of tasks throughout their workday can make it easier for pulp and paper manufacturers to hire and retain personnel in these positions. With the efficiencies of automation and well-trained, experienced personnel, manufacturers can improve productivity in many areas, making robotics retrofits worth the investment.
Enhancing Safety Through Automation
The primary advantage of integrating smelt spout cleaning robots into pulp and paper mills is the enhancement of operator safety. Manual cleaning of smelt spouts exposes operators to a variety of hazards including extreme heat, hazardous chemicals, and physical strain. Automation mitigates these risks by removing operators from the immediate vicinity of these dangers.
Reducing Exposure to Hazards
Molten smelt, green liquor, and hot gases are all byproducts of the recovery boiler process. When operators manually clean smelt spouts, they are in close proximity to these hazardous materials. Robots, on the other hand, can withstand these extreme conditions without risk, thereby significantly reducing the exposure of human operators to these dangers. The automation of smelt spout cleaning also reduces the likelihood of accidents caused by human error, which can be a significant factor in hazardous environments.
Ergonomic Benefits
Repetitive-motion injuries are a common concern in many industrial settings, and the pulp and paper industry is no exception. Manual smelt spout cleaning requires operators to perform repetitive tasks that can lead to back, shoulder, and other musculoskeletal injuries over time. By automating this process, operators are spared from these repetitive motions, reducing the incidence of work-related injuries and the associated costs and downtime.
Improved Emergency Response
In addition to routine safety benefits, the integration of robots can enhance emergency response capabilities. For example, if an unexpected problem occurs within the recovery boiler system, the robot can be quickly deployed to assess and address the situation without putting human operators at risk. This rapid response can be critical in mitigating damage and ensuring the safety of personnel.
Boosting Productivity with Automation
While the safety benefits of smelt spout cleaning robots are significant, their impact on productivity is equally important. Automation can lead to more consistent and efficient cleaning cycles, which in turn enhances the overall performance of the recovery boiler.
Consistent Cleaning Cycles
Manual cleaning schedules are often limited by the availability and stamina of human operators. Robots, however, can maintain a consistent cleaning schedule without breaks, leading to more frequent and thorough cleaning cycles. This consistency ensures that the smelt spouts remain clear of obstructions, which can improve the efficiency of the recovery boiler and reduce the likelihood of unscheduled shutdowns.
Increased Operational Uptime
By reducing the need for manual cleaning, robots can also help increase the operational uptime of recovery boilers. Since the robots can perform their tasks without requiring a full or partial shutdown of the boiler, mills can maintain higher levels of productivity. This increased uptime translates into higher output and profitability for the facility.
Optimization of Human Resources
With robots handling the labor-intensive task of smelt spout cleaning, human operators can be redeployed to other critical areas within the facility. This optimization of human resources can lead to more efficient operation of the entire mill. Operators can focus on tasks that require human judgment and expertise, such as monitoring system performance, conducting quality control checks, and performing maintenance on other equipment.
Economic Considerations
Investing in smelt spout cleaning robots represents a significant financial commitment for pulp and paper mills. However, the long-term economic benefits of this investment can outweigh the initial costs.
Cost Savings from Reduced Injuries
One of the most immediate economic benefits of automation is the reduction in costs associated with workplace injuries. Medical expenses, workers' compensation claims, and lost productivity due to injuries can be substantial. By reducing the incidence of these injuries, mills can achieve significant cost savings.
Improved Boiler Efficiency
The improved cleaning consistency provided by robots can lead to more efficient operation of the recovery boiler. This efficiency can result in lower fuel consumption, reduced wear and tear on the boiler components, and improved overall performance. These factors can contribute to significant cost savings over the life of the boiler.
Return on Investment
While the initial cost of purchasing and installing a smelt spout cleaning robot can be high, the return on investment (ROI) can be substantial when considering the long-term benefits. Increased productivity, reduced downtime, and cost savings from fewer injuries can all contribute to a positive ROI. Additionally, many manufacturers offer financing options or leasing programs that can help offset the upfront costs.
Challenges and Solutions in Implementing Robotic Solutions
Despite the clear benefits of smelt spout cleaning robots, there are challenges that mills may face when implementing this technology. Understanding these challenges and the solutions available can help mills successfully integrate robots into their operations.
Space Constraints
One of the primary challenges in retrofitting existing recovery boilers with smelt spout cleaning robots is the limited space available in many facilities. The design of the robot and its mounting system must accommodate these space constraints while still providing effective cleaning.
Innovative Mounting Solutions
As mentioned earlier, innovative mounting solutions such as hanging mounts and linear rail assemblies can help overcome space constraints. These designs allow the robot to move efficiently within a confined area, ensuring thorough cleaning without requiring extensive modifications to the existing infrastructure.
Integration with Existing Systems
Integrating a new robotic system with existing boiler controls and monitoring systems can be complex. Ensuring compatibility and seamless communication between the robot and the boiler control system is critical for effective operation.
Collaborative Design and Integration
Working with an experienced automation designer who understands the specific needs of the pulp and paper industry is essential for successful integration. These designers can collaborate with mill personnel to develop a customized solution that fits the unique requirements of the facility. Thorough testing and validation during the design and installation phases can also help ensure smooth integration.
Training and Support
Introducing new technology into an industrial setting requires proper training and support for operators and maintenance personnel. Ensuring that staff are comfortable with the new system and understand how to operate and maintain it is crucial for long-term success.
Comprehensive Training Programs
Manufacturers of smelt spout cleaning robots typically offer comprehensive training programs for mill personnel. These programs cover everything from basic operation to advanced troubleshooting and maintenance. Ongoing support and access to technical expertise can also help mills address any issues that arise and ensure the continued success of the robotic system.
Future Trends in Pulp and Paper Mill Automation
The adoption of smelt spout cleaning robots is part of a broader trend towards increased automation in the pulp and paper industry. As technology continues to advance, new opportunities for automation and optimization will emerge.
Advanced Monitoring and Diagnostics
Future generations of smelt spout cleaning robots may incorporate advanced monitoring and diagnostic capabilities. These features can provide real-time data on the condition of the smelt spouts and the overall performance of the recovery boiler. This information can be used to predict maintenance needs, optimize cleaning schedules, and further improve efficiency.
Integration with Industry 4.0
The concept of Industry 4.0 involves the integration of digital technologies into industrial processes. Smelt spout cleaning robots could be connected to a broader network of sensors and control systems, enabling more sophisticated data analysis and decision-making. This integration can lead to smarter, more responsive operations and further enhance productivity and safety.
Collaborative Robots
Collaborative robots, or cobots, are designed to work alongside human operators. In the future, smelt spout cleaning robots may evolve to incorporate collaborative features, allowing them to assist operators with a wider range of tasks. This collaboration can enhance the capabilities of both robots and human workers, leading to even greater efficiencies.
The introduction of smelt spout cleaning robots into North American pulp and paper mills represents a significant advancement in both safety and productivity. By automating a hazardous and labor-intensive task, these robots can protect operators from harm, reduce the incidence of repetitive-motion injuries, and increase the efficiency and uptime of recovery boilers.
While the initial investment in robotic technology can be substantial, the long-term benefits in terms of cost savings, improved boiler performance, and enhanced worker safety make it a worthwhile consideration for many mills. As technology continues to advance, the integration of smelt spout cleaning robots and other automated solutions will play an increasingly important role in the future of the pulp and paper industry.
By embracing these innovations, pulp and paper mills can create safer, more productive work environments and position themselves for continued success in a competitive industry.
