quimica industrial tercera parte 11 05

Control of Heat in Cooking

Managing Heat Flow

• The discussion begins with the importance of controlling heat when cooking, specifically mentioning the need to reduce flame once boiling is achieved.

• The position of the burner knob is crucial; it can be open, closed, or in an intermediate position to regulate heat flow effectively.

Technical Difficulties

• A technical issue arises with a power supply, prompting a 10-minute break for troubleshooting.

• The instructor reassures students that they are still connected and addresses concerns about feeling isolated during online classes.

Examples of Temperature Regulation

Hot Water Experience

• An analogy is drawn using hot water taps, where one controls the temperature by adjusting valves for hot and cold water.

• Finding the right balance between hot and cold water leads to a comfortable bathing experience.

Valve Positions

• The positions of both hot and cold valves are typically set to an intermediate level for optimal regulation.

• This concept illustrates how control valves operate at intermediate angles rather than fully open or closed.

Types of Control Valves

Characteristics of Control Valves

• Control valves function primarily in an intermediate position, unlike manual or motorized valves which are either fully open or closed.

Actuators Used

• Most control valves utilize pneumatic actuators powered by air; motorized actuators are less common due to safety concerns regarding ignition sources.

Pneumatic vs. Motorized Actuators

Safety Considerations

• Pneumatic actuators are preferred as they do not pose ignition risks compared to electric motorized actuators which can fail more easily due to their complexity.

Practical Applications

• While it's possible to find motorized actuators in some plants, their use is limited because they introduce potential hazards not present with pneumatic systems.

Understanding Valve Components

Anatomy of Valves

• Visual aids (Figures A1 and A2 referenced), show differences between manual and motorized valve bodies; both share similar structures but differ in operation methods.

Functionality Explained

• The actuator's role involves moving components based on air pressure rather than mechanical handles found in manual systems.

Mechanism of Air-Powered Valves

Operation Principles

• Air pressure plays a critical role in closing these types of valves; when air pressure exceeds spring tension, it allows closure through deformation of a diaphragm.

Closing Mechanism

• As the plug approaches the seat ring within the valve body, it seals off flow effectively when air pressure is applied correctly.

Clarifications on Terminology

Key Terms Defined

• Definitions provided for terms like "actuator," "diaphragm," and "stem" help clarify discussions around valve mechanics.

Historical Context

• Discussion touches on historical materials used in rubber products such as inner tubes versus modern applications.

Understanding Control Valves and Their Mechanisms

Introduction to Diaphragm Valves

• The diaphragm valve operates using an elastomer that deforms under air pressure, overcoming the spring's resistance to function.

• There are no mechanical components like motors or gears involved in this operation; it relies solely on air pressure.

Functionality of Air Pressure

• When air is applied, it pushes down on the diaphragm, allowing the valve to close by overcoming the spring force.

• This type of valve is termed "fail open" because, without air supply, the spring keeps it fully open.

Characteristics of Control Valves

• The control valve can also close if sufficient pressure is applied; however, its primary function isn't sealing completely.

• While new ball valves can be hermetic (completely sealed), they often operate in intermediate positions leading to potential erosion over time.

Erosion and Material Considerations

• High velocities in small spaces between the plug and seat can cause erosion at critical points due to wear from fluid dynamics.

• Special high-hardness alloys are used in manufacturing these valves to mitigate erosion effects.

Hermeticity and Valve Performance

• Hermeticity classification depends on materials used for construction; harder materials provide better long-term sealing capabilities.

• Even if a valve closes effectively initially, erosion may lead to leaks over time as seals degrade.

Fail Open vs. Fail Closed Mechanisms

Understanding Fail Open Design

• In a fail-open design, when there’s no instrument air supply, the spring lifts everything up keeping the valve open.

• This design ensures that loss of air results in an open state rather than a closed one for safety reasons.

Clarifying Misconceptions about Failures

• The term "failure" refers not to a malfunction but rather what happens when instrument air is lost—leading to an open position.

• It's important not to confuse this with actual mechanical failure where parts break or malfunction.

Adjusting Control Flow with Instrumentation

Configuring Control Valves

• Control valves can be adjusted so that they remain fully open based on specific set points even when instrument air flow is cut off.

Discussion on Adjustment Points

• A participant raises concerns about adjustment points being unclear; further clarification will be provided later in discussion.

Transforming Valve Positions

Changing Valve Configuration

• To convert a fail-open valve into a fail-close configuration requires repositioning components such as placing the spring above instead of below.

Visualizing Changes

• By altering where components are placed within the system (like moving springs), you can change how the valve responds when losing air pressure.

Conclusion: Importance of Understanding Valve Mechanics

Summary of Key Concepts

• Understanding how diaphragm valves work and their configurations (fail-open vs. fail-close).

Final Thoughts

• Knowledge about material properties affecting hermeticity and performance longevity is crucial for effective industrial applications.

Válvulas de Control y su Funcionamiento

Características de las Válvulas de Control

• Las válvulas de control con actuador neumático pueden estar completamente abiertas o cerradas, dependiendo de la presencia del aire de instrumentación.

• Se utilizan las siglas "Fail Open" (FO) para indicar que una válvula se abre en caso de falla, y "Fail Close" (FC) para cuando se cierra.

Nomenclatura y Clasificación

• La tabla 3.1 presenta una nomenclatura alternativa para especificar fallas seguras en aulas de control; si el actuador es motorizado, la válvula falla en su última posición.

• Las fugas en las válvulas se clasifican desde clase 1 hasta clase 6, siendo esta última la más hermética según el estándar ANSI F67002.

Erosión y Fugas

• Las aulas de control no garantizan un cierre hermético debido a la erosión entre el tapón y el asiento.

• Con el tiempo, incluso las válvulas nuevas pueden presentar fugas al cerrarse debido a la erosión.

Materiales y Hermeticidad

• Las válvulas clase 6 están fabricadas con materiales exóticos que resisten mejor la erosión, manteniendo así su hermeticidad por más tiempo.

Ingeniería Actual: Proyectos Industriales

Introducción a Proyectos Industriales

• Se hace una pausa para motivar a los estudiantes mostrando cómo se realizan actualmente los proyectos industriales, específicamente en plantas compresoras.

Visualización 3D en Ingeniería

• Se utiliza un programa llamado Navis.org como visualizador gratuito para esquemas 3D; permite ver longitudes pero no modificar diseños.

Herramientas Utilizadas

• AutoCAD es mencionado como uno de los programas más utilizados para crear maquetas en 3D; Micro Station también es reconocido como un software relevante.

Detalles Técnicos del Proyecto

Componentes del Compresor

• Se observa un motor de gasolina conectado a un compresor; se detallan los cilindros del compresor sin pérdida de resolución.

Identificación y Funciones

• Los componentes incluyen separadores que amortiguan pulsaciones y válvulas que indican funciones específicas mediante códigos de colores.

Soporte e Instalación

• La instalación requiere soporte adecuado para todas las tuberías, lo cual es crucial para asegurar funcionalidad y seguridad.

Especificaciones Técnicas Detalladas

Información sobre Tuberías

• Al seleccionar segmentos específicos dentro del software, se puede acceder a detalles técnicos como peso y longitud estándar (8 pulgadas).

Importancia del Detalle Técnico

• Realizar ingeniería con este nivel de detalle previene problemas durante la construcción al asegurar que todos los elementos encajen correctamente.

Engineering Precision in Mechanical and Civil Work

Importance of Support Structures

• All pipes must be supported; this is crucial for mechanical and civil engineering. Proper support prevents pipes from hanging, ensuring structural integrity.

• Discussion on automatic valves, specifically a 10-inch ball valve used as a shutdown mechanism during emergencies.

Understanding Actuators

• Actuators are essential components that control the opening and closing of emergency valves. Their design is critical for safety measures in engineering systems.

• The actuator's geometry is important, although specific details were not provided in the discussion.

Pressure Management in Tanks

Tank Operations

• There are pressurized and non-pressurized tanks connected by a valve that regulates pressure transfer between them.

Relief Valves Overview

• Relief valves are equipped with an entry valve and a manual exit valve to manage pressure safely within systems.

Instrumentation and Color Coding

Instrument Specifications

• Inquiry about color coding for instruments; understanding these specifications aids in identifying equipment quickly.

Modern Engineering Practices

Compression Systems

• Introduction to modern compression systems featuring five compressors designed to manage gas pressures effectively.

Safety Measures Around Mechurrio Systems

• Mechurrios (flame arrestors or burners at ground level), designed to minimize visual impact while ensuring safety from ignition sources.

Environmental Considerations

Minimizing Visual Impact

• Ground-level mechurrios burn cleanly without smoke, reducing environmental visibility concerns, especially in sensitive areas like jungles.

Electrical Generation Insights

Generators Overview

• Discussion on electricity generation using gas turbines; clarification on equipment identification was noted as potentially lacking due to service-related labeling practices.

Contributions to Project Design

Role of Engineers

• Exploration of how engineers contribute to project designs, particularly regarding the integration of mechanical supports and system specifications.

Collaboration Between Disciplines

• Acknowledgment that both civil and mechanical engineers play roles in designing support structures, emphasizing collaboration across disciplines for effective project execution.

Designing Hydraulic Systems and Skids

Overview of Equipment Sizing

• The speaker discusses the sizing of relief valves and pipes, emphasizing that they are designed in-house. Relief valve pipes have different criteria compared to process pipes.

• Process pipes, illustrated as white in the presentation, have restricted pressure drop velocities, unlike relief valve pipes which can handle much higher speeds.

Hydraulic Design Responsibilities

• The design team is responsible for all hydraulic aspects including diameter and arrangement; mechanical engineers later handle equipment layout.

• Each stage of protection requires careful sizing of relief valves to ensure safety across various operational stages.

Understanding Skids

• The term "skid" refers to pre-built platforms that house equipment like compressors and dehydration units, allowing for easier installation.

• Skids come with pre-installed flanges for connection to other systems, streamlining the assembly process.

Engineering Complexity and Timeframes

• Designing a comprehensive system typically takes about six months, highlighting the complexity involved in creating detailed engineering plans.

• Those who create these designs are known as project designers or "proyectistas," possessing specialized knowledge essential for stability and accuracy.

Importance of Detailed Plans

• Engineering software used is not just for drawing but includes precise scaling and material lists, ensuring every component is accounted for.

• Intelligent plans incorporate extensive details down to individual components like elbows and screws, facilitating accurate cost estimation.

Professional Demand and Skill Level

• Project designers are highly sought after due to their expertise; they often earn more than newly graduated engineers because of the demanding nature of their work.

• The level of detail required in modern engineering practices is significant; even small items like washers must be included in calculations.

Conclusion Remarks

• The speaker emphasizes that while mechanical engineers finalize equipment placement, hydraulic engineers determine critical specifications such as diameters and pressures.

• Acknowledgments were made towards participants at the end of the session, indicating a collaborative learning environment.