In process industry, failure or rupture of pressurized vessel is very dangerous especially when there is an escape of flammable gaseous mixture that can cause potential fire or explosion. One of the scenarios that causes such accidents is the blowdown process. Therefore, it becomes crucial to control blowdown process to prevent such accidents. It is important to design optimally to make sure that blowdown valve is according to the requirements. For the safe use of a pressure relief system, some of the parameters are critical, for example, selection of construction material, sizing of relief valves, temperature, and pressure, etc. There is no literature currently available that discusses all the mathematical models or simulation tools for optimum design of the blowdown process. This subject matters because the available models or tools cover different aspects of blowdown process. A meticulous review is required to present the applications of these models and tools based on the accidental scenarios. Therefore, this paper critically reviews the models and tools that are developed purposely to calculate optimum blowdown parameters based on fluid and vessel conditions. Recommendations are given for the development of new simulation tool to simulate phase change conditions especially when solid formation is involved.

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In this study, systematic literature review was applied to comprehensively gather and analyze existing research on blowdown processes, safety considerations, modeling techniques, and simulation tools related to pressurized vessels and pipelines. The methodology involved a structured search of relevant literature sources, meticulous data collection, rigorous analysis of key findings, and synthesis of information to provide a thorough overview of the current state of knowledge in the field.

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Safety Enhancement: By optimizing blowdown processes and ensuring the selection of appropriate materials and sizing of relief valves, the study directly contributes to enhancing safety in the process industry.

Risk Reduction: The critical analysis of existing models and tools enables identifying gaps and areas for improvement in blowdown design, thereby reducing the risk of accidents and potential hazards in industrial settings.

Efficiency Improvement: Optimal blowdown design leads to more efficient operations in the process industry, minimizing unnecessary loss of materials and energy during blowdown and resulting in cost savings and improved resource utilization.

Cost Savings: Optimized blowdown processes reduce material and energy losses, leading to cost savings for industrial facilities.

Resource Utilization: Efficient blowdown processes ensure better utilization of resources, minimizing waste and maximizing productivity.

Innovation and Development: Recommendations for new simulation tools foster innovation and advancement in blowdown process modeling, contributing to continuous improvement in safety practices and operational efficiency.

Knowledge Advancement: The study consolidates existing research and identifies avenues for future research and development, advancing knowledge in process safety engineering and providing valuable insights for researchers, engineers, and practitioners.

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Safety Corner and Critical Parameters: The paper underscores the critical importance of safety in blowdown processes, highlighting the potential hazards associated with uncontrolled blowdown, such as fire or explosion. It emphasizes the need for precise control of parameters like material selection, relief valve sizing, temperature, and pressure to ensure the safe operation of pressure relief systems.

Gap in Literature and Research: The review identifies a significant gap in the existing literature concerning mathematical models and simulation tools for designing optimal blowdown processes. This gap indicates a lack of comprehensive resources for engineers and researchers to reference when developing blowdown systems for pressure vessels and pipelines.

Challenges Faced by the Industry: The paper discusses the challenges that industries encounter in depressurization processes, such as the need for reliable models validated against large-scale experimental facilities. It also highlights the importance of conducting more extensive studies on different gas mixtures, exploring blowdown under various conditions (including fire and cryogenic scenarios), and developing new numerical models to address specific challenges like dry ice formation.

Recommendations for Improvement and Innovation: The review paper provides valuable recommendations for improving existing models and simulation tools. These recommendations include developing new numerical models to overcome specific challenges, studying the effects of additives to prevent solidification during blowdown, and exploring innovative approaches to enhance the validity and applicability of simulation tools. By implementing these recommendations, industries can make informed decisions, reduce hazards, and improve safety measures in blowdown processes. Additionally, the potential for innovation highlighted in the paper suggests that addressing research areas can lead to broader applications beyond depressurization processes, offering solutions to various system simulation challenges

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Innovation and Technology Development: The necessities for the development of new simulation tools to simulate phase change conditions, especially in scenarios involving solid formation, presents an opportunity for innovation and technology advancement in the field of blowdown processes.

Efficiency and Cost-Effectiveness: Implementing efficient blowdown systems based on advanced simulation tools can help companies optimize their processes, reduce downtime, and minimize operational costs.

Safety and Enviornmental Compliance: By developing accurate models and tools for calculating optimum blowdown parameters, companies can enhance safety measures and ensure compliance with environmental regulations. This can lead to increased market trust and credibility, attracting more clients who prioritize safety and sustainability

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