(143a) Safety and Procedural Enhancements of Flushing Operations in Petroleum Pipelines

The petroleum lubricants industry faces the unique challenge of product cross-contamination during sequential production and packaging operations. These industries manufacture and package a variety of unique lube oil compositions throughout the year (Parkash 2009). A multiproduct pipeline system is used for sequentially packaging over 2000 batches of final products depending upon the customer demands (Zlokarnik 2001). Therefore, between each change-over operation, there is a need to clear these lines and ensure product purity (Baptista et al. 2000). Most of the straight-pipeline sections can be cleared out using tools such as a piping inspection gauges (PIG), but there are more complex pipe networks with variable diameters and auxiliary equipment that cannot be cleaned using traditional methods (Tiratsoo 2013). These industries must use pure oil to clear these unpiggable sections of the residual oil in the lines to prepare for the next product. This process of flushing generates mixed oils that has low economic value and functionality (Li et al. 2023; Camussi, Cerdá, and Cafaro 2021). The goal of this work is to minimize the amount of mixed oil produced in each changeover by optimizing the flushing process (Baptista et al. 2000; Bamoumen et al. 2022).

Our project focuses on applying creative solutions to reduce the amount of mixed oil produced in each flush. Our research has revealed that minor procedural changes can make significant improvements in the flushing operations, with little to no additional capital costs for the stakeholders. The effect of temperature, efficacy of pressurized air blowing, and safety concerns all are contributing factors when designing an improved procedure. The finalized procedure incorporates air-blowing through the pipelines to reduce the amount of residual oil left in the lines and therefore reducing the amount of new oil required. These procedural changes were tested on a newly developed benchtop pilot plant; less flush oil was required using the air-blowing enhancements. This new procedure then underwent a scale-up analysis for a larger diameter section of pipe where the improved procedure still proved viable, safe, and effective for an industrial-scale packaging plant. These newly developed procedural enhancements can revolutionize pipeline flushing operations and benefit petroleum industries worldwide.

Originally, the study conducted had a focus on identifying the economic benefits of optimizing the operations of these packaging plants. However, the safe operation of these lines is a significant concern as it directly links to ‘good manufacturing practices’ and workplace safety guidelines implemented by regulatory agencies such as OSHA (Occupational Safety and Health Administration). Some of the hazards identified include aerosolization of harmful lubricant products, improper procedural enforcement, and inconsistent product characteristics.

The identification of the hazards associated with this process is only the first step. Addressing the hazards in a way that does not interfere with the day-to-day operations of the facility is equally important. In order to study the effect of these hazards on operator safety, a series of benchtop experiments were performed. These experiments simulated the physical environment of the operator, including spacing out process controls to mimic the accessibility in a real plant. This involved placing sensors and control valves that mimic the real plant and its constraints in regards to space and accessibility. These procedural changes were also tested to determine their operational safety.

The changes in the benchtop scale system were recorded and the flushing experiments were conducted using the standard operating procedures. Furthermore, the detailed economics and process safety indicators were calculated and compared against the base case. Thishighlighted both the economic and process safety benefits of the procedural enhancements. Developing easy to understand standard operating procedural outlines, combined with operator training is a critical factor in implementing changes that improve process safety. To test the efficacy of the solutions presented, the team conducted in person operator training over a three-month period at the partnered packaging plant. By systematically identifying process hazards, swift actions were taken to ensure the safety of the operators, while also providing an economic benefit to the production plant.

References:

Bamoumen, Meryem, Selwa Elfirdoussi, Libo Ren, and Nikolay Tchernev. 2022. “Continuous Time and Volume Batch Formulation for the Multiproduct Pipeline Network Scheduling Problem.” IFAC-PapersOnLine 55 (10): 2282–87. https://doi.org/10.1016/j.ifacol.2022.10.048.

Baptista, Renan Martins, Felipe Bastos de Freitas Rachid, and José Henrique Carneiro de Araujo. 2000. “Estimating Mixing Volumes Between Batches in Multiproduct Pipelines.” In Volume 2: Integrity and Corrosion; Offshore Issues; Pipeline Automation and Measurement; Rotating Equipment, V002T08A008. Calgary, Alberta, Canada: American Society of Mechanical Engineers. https://doi.org/10.1115/IPC2000-247.

Camussi, Nélida B., Jaime Cerdá, and Diego C. Cafaro. 2021. “‘Mathematical Formulations for the Optimal Sequencing and Lot Sizing in Multiproduct Synchronous Assembly Lines.’” Computers & Industrial Engineering 152 (February): 107006. https://doi.org/10.1016/j.cie.2020.107006.

Li, Yansong, Dong Han, Baoying Wang, and Jianfei Sun. 2023. “An Industrial Scale Simulation Method for Predicting the Contamination Evolution in Long-Distance Multiproduct Pipelines.” Journal of Pipeline Systems Engineering and Practice 14 (1): 04022054. https://doi.org/10.1061/(ASCE)PS.1949-1204.0000696.

Parkash, Surinder. 2009. Petroleum Fuels Manufacturing Handbook: Including Specialty Products and Sustainable Manufacturing Techniques. 1 edition. New York: McGraw-Hill Education.

Tiratsoo, John. 2013. Pipeline Pigging & Integrity Technology, 4th Ed. Beaconsfield: Clarion Technical Publishers.

Zlokarnik, Marko. 2001. Stirring: Theory and Practice. Wiley. https://doi.org/10.1002/9783527612703.