Fuel Gas Skid

Test Your Knowledge

Fuel Gas Skids Quiz

Instructions: Choose the best answer for each question.

1. What is the primary function of a fuel gas skid? a) To store natural gas for future use. b) To transport natural gas from the wellhead to processing facilities.

2. Which of the following is NOT a typical component of a fuel gas skid? a) Filters b) Separators c) Pressure Regulators

3. Fuel gas skids are used in which of the following applications? a) Powering turbines and boilers b) Driving compressors for gas pipelines

4. What is the main benefit of using a fuel gas skid for instrument air systems? a) Increased storage capacity for instrument air b) Reduced maintenance requirements

5. Which of the following is NOT a benefit of using a fuel gas skid? a) Reliability b) Safety c) Efficiency

Fuel Gas Skid Exercise

Scenario: A process plant requires a fuel gas skid to power a 10 MW gas turbine. The turbine requires a fuel gas pressure of 5 barg and a flow rate of 1000 Nm³/hr. The incoming natural gas stream has a pressure of 10 barg and contains traces of water and condensate.

Task: Design a basic fuel gas skid system for this application. Your design should include the following:

1. Components: List the essential components of the fuel gas skid and their functions.
2. Flow Diagram: Draw a simple flow diagram showing the flow path of the gas through the skid.
3. Safety Considerations: Identify at least 3 safety considerations that should be factored into the skid design.

Techniques

Fuel Gas Skids: A Comprehensive Guide

This guide expands on the fundamental information about fuel gas skids, breaking down the topic into key areas for a clearer understanding.

Chapter 1: Techniques Used in Fuel Gas Skid Design and Operation

Fuel gas skid design and operation rely on several key techniques to ensure efficient and safe fuel delivery. These techniques are crucial for removing contaminants, regulating pressure, and monitoring performance.

1.1 Gas Conditioning: This involves several processes aimed at purifying the raw natural gas. Common techniques include:

• Filtration: Removing particulate matter using various filter types (e.g., coalescing filters, particulate filters) based on the specific contaminants and flow rates.
• Separation: Separating liquid hydrocarbons (condensate) and water from the gas stream using devices like three-phase separators or knockout drums. Proper sizing is critical for efficient operation.
• Dehydration: Removing water vapor using desiccants or refrigeration techniques to prevent hydrate formation and corrosion downstream.

1.2 Pressure Regulation: Maintaining consistent downstream pressure is vital. Techniques used include:

• Pressure Reducing Valves (PRVs): These valves automatically regulate the pressure to a setpoint, preventing over-pressurization of downstream equipment. Selection of appropriate PRV type (e.g., spring-loaded, pilot-operated) is crucial based on pressure ranges and flow requirements.
• Pressure Relief Valves (PRVs): Safety devices to protect the skid and downstream equipment from over-pressure conditions. These are sized to handle potential surges or failures.

1.3 Flow Control: Precise control of gas flow is essential for optimized fuel delivery and safety. Techniques include:

• Control Valves: Regulating the gas flow based on downstream demand or pre-set parameters. These are often integrated with the skid's control system.
• Flow Meters: Accurately measuring the gas flow rate for monitoring and control purposes. Different meter types (e.g., orifice plates, turbine meters) are available, chosen based on accuracy and flow range requirements.

1.4 Monitoring and Control: Modern skids incorporate advanced instrumentation and control systems for real-time monitoring and automated operation:

• Instrumentation: Pressure gauges, temperature sensors, flow meters, and level indicators provide data for monitoring system performance.
• Control Systems: Programmable Logic Controllers (PLCs) or Distributed Control Systems (DCS) automate processes, manage alarms, and provide remote monitoring capabilities.

Chapter 2: Models of Fuel Gas Skids

Fuel gas skids are available in various configurations tailored to specific application needs and site conditions. Key model variations include:

• Standard Skids: Pre-engineered and pre-fabricated units designed for common applications and flow rates. These offer quicker deployment and lower costs.
• Custom Skids: Designed and built to meet unique application requirements, incorporating specialized components and features. These provide greater flexibility but require longer lead times and higher costs.
• Modular Skids: Built using standardized modules that can be combined and configured to meet specific needs, offering flexibility and scalability.
• Mobile Skids: Designed for portability and easy relocation to different sites. These are typically mounted on trailers or skids for easy transportation.

Different models also vary in their capacity (flow rate), pressure ratings, and the level of automation incorporated. Factors influencing model selection include:

• Gas Composition: The type and concentration of contaminants influence the choice of conditioning equipment.
• Pressure Requirements: Downstream equipment dictates the necessary pressure regulation capabilities.
• Flow Rate: The amount of fuel gas required determines the capacity of the skid.
• Environmental Conditions: Ambient temperature, humidity, and other environmental factors influence the design and selection of components.

Chapter 3: Software Used in Fuel Gas Skid Design and Operation

Software plays a critical role in the design, simulation, and operation of fuel gas skids.

• Computer-Aided Design (CAD) Software: Used for designing the skid layout, selecting components, and generating detailed drawings. Examples include AutoCAD, SolidWorks.
• Process Simulation Software: Used for modeling the gas processing steps and predicting system performance under various operating conditions. Examples include Aspen Plus, HYSYS.
• PLC Programming Software: Used for programming the PLC controlling the skid's automated operations. Examples include Rockwell Automation Studio 5000, Siemens TIA Portal.
• SCADA Systems: Supervisory Control and Data Acquisition systems allow remote monitoring and control of the skid, providing real-time data visualization and alarm management.

Chapter 4: Best Practices for Fuel Gas Skid Operation and Maintenance

Following best practices is crucial for safe and efficient operation of fuel gas skids.

• Regular Inspection: Frequent visual inspections to identify potential leaks, corrosion, or other issues.
• Preventive Maintenance: Scheduled maintenance activities to prevent equipment failure. This includes filter changes, valve inspections, and pressure testing.
• Safety Procedures: Strict adherence to safety protocols, including lockout/tagout procedures during maintenance.
• Operator Training: Well-trained operators are essential for safe and efficient operation.
• Data Logging and Analysis: Regularly review data from the skid's monitoring system to identify trends and optimize performance.
• Emergency Response Plan: Having a plan in place to handle leaks or other emergencies.

Chapter 5: Case Studies of Fuel Gas Skid Applications

Case studies demonstrate the diverse applications and benefits of fuel gas skids. Specific examples would showcase applications in different oil and gas processing environments, highlighting specific challenges and solutions. Examples might include:

• Offshore Platform Fuel Gas System: A case study focusing on a skid designed for a harsh offshore environment, addressing challenges like corrosion resistance and remote operation.
• Onshore Refinery Fuel Gas Supply: A case study emphasizing high-volume fuel delivery to a refinery, demonstrating the reliability and scalability of a large-capacity skid.
• LNG Plant Instrument Air System: A case study highlighting the modification of a fuel gas skid to provide high-quality instrument air for critical control systems.

These case studies would detail the skid design, operational performance, and any unique challenges overcome during implementation. They would further illustrate the cost-effectiveness and reliability benefits of using fuel gas skids in various industrial settings.