Introduction
Clean-in-place (CIP) is a crucial process in the food, dairy, and beverage industries to maintain sanitary conditions and prevent product contamination during production. Traditional CIP methods have been employed for years, ensuring effective cleaning of process lines. However, as industries strive for greater efficiency, reduced resource consumption, and improved cleaning capabilities, innovations in the CIP process have become essential.
This blog explores the traditional methods of CIP and introduces innovative technologies that optimize chemical, energy, and water consumption while delivering better cleaning performance. By combining traditional technologies with the latest innovative technologies, industries can take a significant step forward in achieving more cost-effective and sustainable CIP systems.
Traditional CIP Methods
The traditional CIP process has been widely employed in various industries, showcasing its adaptability and effectiveness in ensuring sanitary conditions and mitigating product contamination. Over the years, the process has undergone numerous iterations, each with nuanced differences tailored to specific applications. As industries continue to seek optimal cleaning solutions, the evolution of the traditional CIP process paves the way for the integration of advanced technologies and innovative approaches to achieve even higher levels of performance and sustainability.
One of the more conventional CIP processes commonly involves the following steps:
Pre-rinse: Water is used to remove loose debris and residues from the equipment, generally at a velocity of 6 ft/s or greater.
Alkaline Cleaning: An alkaline solution is circulated through the process lines. This step method involves the use of solutions, such as caustic soda (sodium hydroxide, NaOH) or potassium hydroxide (KOH), to effectively remove organic residues, fats, oils, and proteins from the surfaces of process equipment and piping. Often the fluid is heated to maximize cleaning properties of the hydroxide detergent.
Intermediate Rinse: Water rinses out remaining alkaline residues.
Acid Cleaning: An acid solution is used to dissolve mineral deposits and scale.
Final Rinse: A final water rinse ensures the removal of all cleaning agents and residues.
Sanitization: Sanitizers kill or reduce the number of microorganisms, such as bacteria, yeasts, molds, and viruses, that may remain on surfaces after the cleaning step
Sterilization: Sterilizers are used to completely eliminate or destroy all forms of microbial life, including bacteria, yeasts, molds, and viruses, from the surfaces of equipment and pipelines. Sterilization is a more intense process than sanitization and is essential in industries where the highest level of microbial control is required to ensure product safety, especially in pharmaceutical, biotechnology, and some food processing applications.
These traditional CIP methods have been effective in maintaining sanitary conditions. However, they come with the requirement of large quantities of chemicals, water, and energy consumption, making the process resource-intensive and expensive. Additionally, the effectiveness of the cleaning in removing stubborn residues can be limited.
comprex©: Impulse Cleaning
comprex©, also known as the impulse cleaning, is a 25 year old patented German technology that finds its origins in the domain of drinking water distribution. Over the last decade, the technology has evolved to cleaning large industrial and sanitary piping systems. As a result of its effectiveness, comprex© cleaning has become commonplace in European cleaning standards across a number of market sectors. This innovative process relies on the controlled pulsed injection of compressed air into a throttled water flow, as depicted in Figure 1.
Image 1: Impulse cleaning qualitative diagram courteously of Hamman GmbH
The impulse cleaning accelerates water slugs to a maximum flow velocity of 65 f/s in less than 0.1 seconds. This rapid acceleration results in an extraordinary increase in wall shear stress compared to steady flow methods, as depicted in the chart in Figure 2. comprex© outperforms traditional water flushing by up to 1,000 times the cleaning forces, all while maintaining lower pressures than conventional methods. As a result, comprex© not only delivers superior cleaning performance but also significantly reduces water consumption and wastewater volume. Less volume required means less energy required for tempered cleaning fluid applications yielding additional savings.
Image 2: Wall shear stress at steady flow with and without acceleration component compared to water flushing for a hydraulically smooth DN 100 pipeline
Like traditional flushing, comprex© technology can be affected by obstructions in pipelines. The effectiveness of comprex© relies on acceleration, which requires a minimum open area to enable proper airflow and cleaning fluid flow. This creates a differential pressure, resulting in fluid velocities along the inner surfaces of pipes and components. It's crucial to assess each inline component in the cleaning path, particularly positive displacement pumps and meters. To overcome potential restrictions, lifting seat relief valves can be utilized where installed.
comprex© distinguishes between two cleaning modes: basic cleaning (curative) and routine cleaning (preventive). During basic cleaning, persistent deposits that have accumulated over time must be eradicated. This type of cleaning is usually scheduled as part of plant shutdowns and may require supplementary upstream chemical cleaning with specialized products to mobilize old, hardened deposits.
Routine cleaning, on the other hand, is a regular part of maintenance aimed at removing product residues that can still be mobilized and have not yet solidified. The comprex© process is particularly effective in reliably eliminating such residues.
Reducing Product Waste with Pigging Technology
Pigging is a technique that has gained popularity in recent years as an effective means to reduce product loss during CIP and product transfer processes. Pigging involves the use of a specialized projectile, known as a "pig," which is designed to travel through the process lines, pushing out the residual product ahead of it and collecting it for reprocessing or disposal.
How Pigging Works
1. Product Recovery: Before the CIP process begins, the pig is inserted into the process lines. By using the product or compressed air as the propellant, the pig effectively recovers the remaining product, leaving minimal product residues in the lines.
2. Reduced Cross-Contamination: As the pig removes the bulk of the product from the lines, the risk of cross-contamination during cleaning is significantly reduced, ensuring the highest standards of hygiene.
3. Resource Savings: Pigging reduces the amount of water and cleaning agents needed for the CIP process since the majority of the product is recovered, resulting in substantial resource savings.
4. Environmental Benefits: The reduction in water and chemical usage also leads to a decrease in wastewater generation, contributing to the overall environmental sustainability of the process.
IMAGE 3: Simplfied model of pig traveling through piping courteously of HPS
Advantages of Pigging Technology
1. Minimized Product Loss: Pigging technology can recover up to 99% of product residues, ensuring valuable product is not wasted during cleaning.
2. Enhanced Efficiency: By reducing the amount of product in the lines, the subsequent CIP process becomes more efficient and requires fewer resources.
3. Cost Savings: The recovery of product and reduced resource consumption lead to cost savings, making pigging a financially attractive investment.
Pigging Challenges
Implementing a pigging system can present several challenges for industries looking to enhance their cleaning processes. One primary challenge is the initial investment required to install the necessary infrastructure, including pig launchers and receivers, along with the pigging equipment itself. The retrofitting of existing pipelines can be complex and may entail disruptions to regular operations during the installation phase. Additionally, the selection of the right pigging technology that suits the specific application and pipeline characteristics can be daunting. Maintaining and cleaning the pigging equipment regularly is another challenge, as neglecting maintenance can lead to reduced efficiency and compromised cleaning results. Moreover, employee training is essential to ensure proper handling of pigging equipment and adherence to safety protocols. Despite these challenges, the potential benefits, such as reduced product loss and enhanced cleaning efficiency, make pigging systems a valuable investment for industries seeking to optimize their cleaning processes.
The Integrated Approach: Achieving Optimal Cleaning Performance and Value
The integration of Conventional CIP, Pigging, and comprex© technologies culminates in a robust Clean-in-Place (CIP) system that yields exceptional cleaning performance and significant long-run cost reductions. By leveraging the strengths of each technology, this integrated approach delivers a comprehensive and efficient cleaning solution that surpasses the capabilities of traditional standalone methods. The combination of Pigging technology at the onset of the cleaning sequence enables recovery of the product that remains in the piping system, reducing product loss and its associated costs. Subsequently, the application of comprex© technology enhances the cleaning process by generating increased wall shear stresses, driving fluid velocities along inner surfaces while reducing required volume of cleaning fluid. This results in the removal of persistent deposits and contaminants, elevating hygiene standards and product quality at a lower cost.
Key Considerations for Implementation
Prior to installation it is important to evaluate design intent and site capabilities, including existing compressed air, electrical, and water flow capacities. Adequate compressed air supply is essential for efficient comprex© and pigging processes. Opt for a centralized location to reduce costs and improve cleaning velocities. Assess available utility streams for heating the cleaning liquid if necessary. Proper evaluation of these factors will optimize cleaning performance and overall efficiency in the integrated CIP system.
System Design: Design will be the most critical step in maximizing your achieving your clean goals. To accommodate the pigging process, several crucial design considerations should be considered to ensure its seamless integration and optimal performance. The first aspect to focus on is the pipeline design, where the selection of the appropriate material and dimensions plays a critical role. Smooth and seamless pipelines minimize friction, facilitating the smooth movement of pigs within the system. Careful consideration of the pipeline's internal diameter is necessary to accommodate the size and type of pigs used for the specific application. There are predesign pipe and tube fittings that specifically address these requirements.
Additionally, pigging frequency and operational objectives must be determined to design an effective system. The operational goals, whether focused on cleaning, product recovery, or batching, should align with the selected type of pigs and a well-defined pigging schedule. Properly sized and designed pig launchers and receivers are crucial for safe and efficient pigging operations.
The selection and arrangement of tanks should align with the specific cleaning requirements and process parameters. Careful evaluation of the process flow, cleaning objectives, and production schedules will help determine the number of tanks needed and their capacities. Utilizing tanks of suitable volumes ensures efficient cleaning cycles and minimizes downtime, optimizing the overall cleaning process.
Image 4: Simplified example of integrated approach using pigging and impulse cleaning
Defining the chemical sequences is vital for achieving effective cleaning performance. Determining the correct sequence of cleaning agents, including detergents and sanitizers, ensures thorough removal of contaminants and persistent deposits. Each cleaning stage must be precisely tailored to the unique process requirements and the type of residue to be cleaned. Sequencing the chemicals correctly will avoid any potential reactions or undesired interactions between cleaning agents, enhancing the cleaning process's overall effectiveness.
Pumps and valves are crucial components in an integrated CIP system, as they facilitate the precise delivery of cleaning agents and control the flow of fluids during the cleaning process. Selecting pumps and valves that are compatible with the cleaning agents used and capable of handling the required flow rates is vital for consistent and efficient cleaning operations. Properly sized pumps and valves enable smooth fluid movement through the system, minimizing pressure drops and optimizing cleaning performance.
Instrumentation and controls play a pivotal role in defining and executing the cleaning sequence. Utilizing advanced sensors and instruments allows real-time monitoring of process parameters such as temperature, pressure, and flow rates. The data collected from these instruments provides valuable insights for ensuring the cleaning sequence's accuracy and efficiency. Additionally, implementing an advanced control system enables automated and precise sequencing of pumps, valves, and cleaning agents, minimizing the risk of errors, and maximizing the repeatability and reliability of the cleaning process.
The combination of traditional CIP methods, comprex© impulse cleaning and pigging represents an exciting and promising approach that synergizes chemical and mechanical cleaning principles to yield significantly improved results. By integrating the strengths of each technology, this innovative approach offers superior cleaning performance, reduced resource consumption, and enhanced hygiene standards.
AUTHOR BIO
Jay Kelly is cofounder and VP of Product Development at Floco Process. Jay has dedicated his career to designing, optimizing, and innovating fluid handling systems. He may be reached at jkelly@flocopro.com or 513-760-3244. For more information, visit www.flocopro.com.