Gas distribution system

Introduction to the Gas distribution system

Gaseous substances are those states of matter which have their atomic and molecular particles in a free-flowing state. They are always ever-expanding and filling up the entirety of the container it is kept in. There are various types of gases that are manufactured and used in industrial applications. Gases like hydrogen, oxygen, methane and its derivatives, nitrogen, and other primary hydrocarbons are utilized for manufacturing various health exchanges and medical equipment.

One of the most important in these gases, which has the greatest number of industrial applications, is natural gas. From industrial central gas distribution pipeline to household end consumers, natural gas and its derivatives power the ever so functioning society now.

  • Gas distribution system: Natural Gas

Acting as an energy source for life in general, right from electricity generation to cooking and transportation, this naturally occurring substance consists of a combination comprising of mostly methane and other hydrocarbons, some alkanes, carbon dioxide, hydrogen sulfide, and the inert gas helium. Its presence has a long history on the planet as the formation takes place when the decomposing matter is exposed to intense heat and pressure from within the earth over a prolonged period.

Its natural form exists in its gaseous state, but industrial manufacturing has enabled the produce of compressed natural gas (CNG) and liquid natural gas (LNG). Though similar, the delivery of both these forms differs from each other, which has made natural gas distribution systems more accessible.

  • Gaseous State

The naturally occurring form of natural gas can be transported via trucks, vessels, and gaseous distribution pipelines. Though the usage of natural gas can be exhaustive and the heavy manufacturing and conversion of this into its derivatives enables the functioning of society as a whole. It is mainly acquired from sedimentary rock deposits by forcing chemicals and water through the services and wells with high enough pressure.

  • Liquid State

Natural gas turns into liquid at a temperature of less than negative 150 degrees Celsius. When cooled from its gaseous state, it loses about 0.0017% of its original volume, which is then transported to the destination using specialized containers. It cannot be used for any application; therefore, it is converted to its gaseous state again by heating the liquified form. 

It is colourless and odourless, giving out nontoxic fumes. This property makes it somewhat of a safety hazard because accidental leakage can’t be detected in its natural state. Hence, distribution systems have instruments in place for adding odorful substances while transporting this gas. 

  • Gas distribution system: Methods of Transporting Natural Gas

Both forms of natural gas can be transported over distances via common industrial material transport chains. Each form has its specialized container, which is used during the process. The following are the transportation methods being followed in the industry today: –

  • Ship/Ocean vessels

Shipping containers are useful for the transportation of both compressed natural gas and liquid natural gas. The difference in the transportation of CNG and LNG makes it quite a hassle to transport both forms at the same time. CNG is compressed to a compact, storable form, whereas LNG is frozen to accommodate the space. Manufacturers tend to ship LNG more as compared to CNG due to the cost implications of its transportation logistics, even though CNG is more cost-effective to manufacture.

Mostly, due to the absence of distribution pipelines and industrial applications of natural gas being demanded all over the continents, end users usually receive LNG from across the ocean, with all of it being converted into the gaseous state at the destination. Then it can be channelled through the distribution pipelines of the plant for application purposes.

  • Trucks

Specialized trucks can be utilized to transport natural gas across short distances.  Trucks should be able to maintain a sufficient temperature to prevent phase change of the liquid. For the majority of short-distance truck transport, compressed natural gas (CNG) is used, as the compressed gas can be maintained at 200bar pressure, which the container can handle.

  • Distribution pipelines

Distribution pipelines provide the most efficient, safe, and fastest means of transportation of gaseous materials. Any outside factors don’t disrupt the transport, and large volumes can be transported with ease.

Gas Distribution pipeline System

Gas distribution pipeline systems are the ones that are facilitated across industries and large-scale transportation chains. These provide the most efficient and large volume transportation, which can be looked into.

  • Gas distribution system: Types Distribution pipelines

Distribution pipelines are classified into various types based on their distribution, size, and volume of transportation. These can be classified as the following: –

  • Flowlines

As the namesake, it’s a system connected to a well that transports the natural gas to different storage facilities and processing plants. Flowlines handle the preliminary handling of the natural gaseous form; it is therefore designed to handle the pure fluid state, which can be volatile.

  • Gathering Distribution pipelines

Gathering distribution pipelines help in accumulating gas from different storage tanks and production facilities to a common collection area or trunk. These help in cumulating the average usage and make plans for more manufacture or order accordingly. 

  • Transmission Distribution pipelines

Any distribution pipeline which acts as a medium of transport between adjacent or far-off storage areas or facilities is called a transmission distribution pipeline. It is usually part of an interconnected network transmitting and storing, and delivering gases based on temperature, pressure, and volume requirements. The corresponding valves can be adjusted to get the desired characteristics. 

  • Gas Distribution pipeline System

The individual distribution pipelines are together a part of the gas distribution pipeline system. This is a network that spreads out over the area of a processing plant or any manufacturing facility which uses natural gas. This type of system has various distribution lines that can also be intra-city based, transporting large volumes of gas per the local requirement. 

All the storage units and collection tankers are also a part of this system which functions together to ensure smooth transport and function of the forms of gases that are to be transmitted at the desired temperature, pressure, and volume.

Gas Distribution pipelines System

An efficient aggregate system where all components are working in tandem to supply the gas throughout an area. End-users depend on this entire system to have their delivery ensured.

  • Components of Gas Distribution pipeline System

The gas distribution system may have the following listed components: –

  • City Gate

The interface between the gas distribution system and the transmission line is called the city gate. The city gate may contain equipment such as temperature and pressure indicators, check valves, emergency valves, odorizing units, and other routine checkups and emergency instruments that can monitor and flow the gas during the transportation process.

  • Gas Distribution Manifold

As the interconnected transmission lines go into different channels, the gas distribution manifold splits the gas into different transmission lines before they can be transmitted. The manifold is an important component as the transmission lines are all different, designed to handle different types of pressure and carry a specific type of volatility. The manifold can segregate the gas into a specific type of transmission line where it can be transported safely. 

  • Pressure Reduction and Metering System

Every gas distribution pipeline system contains a pressure reduction system to regulate the gas pressure when it is in the transmission line, especially under downward flow. The pressure and metering system also play a huge role installed in the city gate as it reduces and maintains the initial flow pressure when the gas is fed to the transmission line. 

This is because the initial high pressure requires greater thickness in the inlet valve of the line as compared to the rest of the system; regulating the pressure aids in saving manufacturing and maintenance costs in the long run.

  • Pressure Indicators and Transmitters

All upstream and downstream channels have pressure indicators on the transmission line cross-section when provides real-time pressure values. These are used along with the transmitters, which send that pressure value to the control/monitor room for the engineers to supervise.

  • Temperature Indicators and Transmitters

The inline distribution systems have temperature indicators installed to measure the transmission temperature of the gas at all times; it is always evident at the city gate during the initial flow. Similar to the pressure transmitters, the temperature reading is also transmitted to the control/monitor room.

  • Gas Scrubbers

Gas scrubbers are responsible for removing the residual particles in a gas stream. These are mostly fitted in the inline valve and city gate where the deposited residue can accumulate to a large extent which may jam and destroy the underlying equipment. Gas scrubbers are important to prolong the life of the entire distribution system and maintain its efficiency.

  • Gas Odorizing Unit

Natural gas is a colourless and odourless fluid. To detect and prevent any accidental leaks, every gas distribution pipeline requires an odorizing unit that adds strong-smelling substances to the gas to make it detectable in an environment.

  • Gas Sampling and Analysis Unit (Gas Chromatograph)

The gas chromatograph analysis the underlying components of the gas. It is installed in the city gate, where it separates the gas into different chromatic channels where it undergoes analysis. This is done to maintain the standards of the regulatory organization in charge of the distribution.

  • Fire and Gas Detection System

These are installed on the city gate, where an automated system detects any accident gas leakage and fire hazard. It is connected to a fire safety and shutdown system, which automatically triggers when any hazard is detected and kicks in the safety and precautionary protocols.

  • Gas Service Lines or Spur Lines

The main transmission lines for the centralized gas supply system in residential buildings are further divided into branches that deliver the gas to each end-user . These branches are called spur lines.  Compared to the transmission lines that carry high-pressure gas for fast and efficient transportation, the spur lines have a relatively low-pressure handling capability as the end-user doesn’t require that high pressure.

  • Gas Compressor Station

The gas compressor station plays an important role in the transportation process when the pressure in the transmission distribution pipeline isn’t sufficient to make the delivery to the end-user. The gas compressor station is installed along the transmission distribution pipeline and also can be used to tune the pressure required by the end-users.

  • Valves

Valves are an important component in a pressure flow system. They provide an air-tight seal between various cross-sections of the distribution pipeline and regulate the travelling gas volume and pressure. Valves have their different types, which can be explained as follows: –

  • Emergency Shutdown Valves:

It is mandatory to install these valves at the inline, though not necessary to use them every time but, whenever the pressure goes above a certain value, it triggers the mechanism and the system shuts down.

  • Isolation Valves:

 Isolation valves work by segregating the gas in a different chamber other than the one being carried by it. It may be done to compress, gasify it again, or perform an inspection of the gas.

  • Check Valves:

It protects the pressure reduction and metering system from backpressure. Due to the distribution pipeline system malfunctioning, the lower upstream pressure may cause a breakage of the system.

  • Gas distribution system: Cathodic Protection System

Cathodic protection systems are important to be in place for gas distribution pipelines in an external environment. Even if the distribution pipeline is externally coated, it can lead to severe damages and potential safety hazards since it’s not entirely corrosion-proof. Cathodic protection systems work by conducting electricity through the outer cathode and more the corrosion away from the surface.

  • Distribution pipeline Isolation Fittings (Isolation Joint or Flange Insulation Kit)

Isolation fittings provide electrical insulation to the different sections of the distribution system. Distribution pipelines are sometimes installed parallel to the overhead electric transmission lines; the insulation provided helps protect the gas flowing inside and prevent fire hazards. Also, the transmitter and detector equipment are protected from any electrical surge.

  • Control Station

A distribution system can be automatic or semi-automatic based on the requirements and design choices. Regardless of the type of system, any gas distribution system will have a control station that will oversee the entire function of the system and take any action deemed necessary for the proper functioning of the system.

Gas distribution system Design and Operation Considerations

Designing and operating a large-scale gas distribution system takes careful planning and detailed surveying of the requirements of the consumers.

  • Gas Consumers

For any upcoming gas distribution system, it is important to survey the number of potential consumers an area is going to have; otherwise, if there’s no demand, the supply will be futile.

  • Gas Volume

Once the consumer survey is figured out, a careful estimate of the volume of gas required by all the consumers needs to be done so that the supply and demand sides always meet at balance.

  • Gas Supply Requirements

Supply requirements refer to the individual needs of all consumers regarding the pressure, temperature, and other factors they need and cater to the pressure reduction and metering system requirements for the same.

  • Process Simulations

The analysis of the parameters needs to be followed during the deployment process and get a rough estimate of the fittings and connections to be made in an area. Hydraulic pressure simulations are also done to determine the location of the PRMS systems.

  • Distribution pipeline Isolation Philosophy

Every distribution system needs regular maintenance; the isolation philosophy here means the need to consider every consumer’s need when supply is disrupted during maintenance. The need for it is to cause as little inconvenience as possible.

  • Line Sizing

Line sizing means assessing the system and requirements and selecting those distribution pipelines that can carry the desired volume of gas to consumers as efficiently and quickly as possible.

  • City Gate Location

Scouting the location of the city gate is the most important part of a distribution system. It should be selected to reduce the distance between the transmission line and the distribution network for the minimum delay in deployment.

  • Pipe Materials

The material used for manufacturing the pipes plays a key role in determining the strength of the distribution system. Special grade steel is used for an external anti-corrosive coating. Other materials and alloys can be considered depending on the requirement.

  • Distribution pipeline Route

The route through with the pipes will go connecting to the consumers should be as economically and ergonomically balanced as possible.

  • Permitting and Regulations

Before any construction work can begin, getting the necessary permissions from the concerned authorities and getting to know the regulations of the area authorities is a must.

  • Distribution pipeline Fittings

Fundamental analysis of the fittings should be done before beginning construction. This is to ensure their compatibility with the distribution pipeline and that everything will be in working order.

  • Distribution pipeline Burial Depth

Burial depth will depend on the design choices for the system and regulation of the local authorities keeping all safety precautions in mind.

  • Distribution pipeline Integrity Assessment

Integrity assessment ensures that the system will operate safely and optimally after construction. Various preliminary testing can be carried out to ensure the integrity of the structure.

  • Cost of Building the Gas Distribution Network

An expenditure estimate shall be done during the planning and design phase to analyze the capital and operating expenditure of the project and future feasibility.

Main Benefits of the Gas distribution system

A gas distribution system can be very effective in increasing supply flow to consumers. Moreover, it also has other advantages like: –

  • Customized pressure and volume based on a requirement can be provided, eliminating wastage
  • High volume delivery will lead to lower costs
  • The delivery and supply parameters can be more precisely adjusted and can be done immediately
  • Safety and precautionary measurements will be automatically triggered in case of any hazard

Main Fields of use of Industrial Central Gas Supply System

Industrial CGS is used in a variety of different sectors, including: –

  • Oil and gas refineries
  • Steel and metallurgy
  • Automotive industry
  • Electricity and power generation
  • Chemical Industry

And various other types of manufacturing and industrial applications.

Choose from Modular Gas Distribution Subsystems

Source inlet: The inlet valve which takes in the gas from the distribution system

Gas panel: A control panel that can be used to regulate volume flow and pressure of the gas according to the requirement

Changeover: A changeover regulator controls the flow between different supply lines/sources for efficient use between all the sources.

Point-of-use: A type of pressure regulator which conserves energy and maintains adjustable inlet and outlet bar pressure.

How can Envigaurd Advisors help?

The team at Envigaurd will provide all sorts of assistance, including but not limited to: –

  • Educating:

Based on client needs and feedback, our professionals will facilitate a plan of action and cater to the overall aspect of the project. The client will be provided all the information about the product and will help them in understanding the scope of the project more effectively.

  • Designing the control flow:

Any project regarding a supply line system requires a proper blueprint of the distribution system and how each segment will get channelled to the next. Our team will provide a robust view of the distribution architecture from the ground up, and each part will be constructed according to the flow diagram.

  • Handling the installation:

The system’s installation will be based on the flow control architecture which will be taken care of by our team of experts. The client will be assured of all the aspects of the system, and any changes required will be thoroughly discussed and implemented.

  • Project Commissioning:

Designing, installation, and testing processes are carried in the presence of the client, who has the final say in project approval. We make sure to deliver at the proper time and tweak any particular change which the client needs before delivering the end product.

  • Support:

Post-delivery support will always be provided to the client, and any issues with individual working parts or the overall flow system will be looked into.

Conclusion

Gas distribution systems are an integrated infrastructure that makes household and industrial applications more suitable for the end-user. Natural gas transportation and supply have their challenges, but we can ensure all precautions and regulations are established with an entirely regulated and safe distribution pipeline. A proper gas distribution system will have its makers do the due diligence on every nook and cranny right until the delivery of the product to the end-user.

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