Pipelines are all around us; they transport water and natural gas to our homes and take away excess water and sewage. But how do fluids move through these vast pipeline networks?
Let's take a look.
A pipe is a hollow cylinder made out of a material like metal, plastic, wood, or even clay, that is used to move substances that flow, like liquids and gases. When several pipes are connected in a series to transport materials over long distances, the resulting structure is called a pipeline.
Pipelines are everywhere; in our walls, floors, streets, fields and prairies, and along rivers, lakes, and seas. They travel underground and over ground, and are used to transport many different products. For example, complex systems of pipelines and plumbing bring clean water and natural gas to our homes and take away excess water and sewage.
Fluids are liquids and gases that continually flow when a force is applied to them. But different fluids react to force differently; they can be compressible or incompressible, which is the big difference between liquids and gases. Liquids are generally incompressible, meaning they don't change volume much in response to pressure change, whereas gases are compressible so will change volume in response to a change in pressure. And whether or not a fluid is compressible will change how it flows when force is applied to it in a pipe.
There are basically two ways to move fluids through a pipe. One way is to tilt the pipe so it flows downhill and gravity provides the force to move the fluids. The second way is to make the pressure at one end of the pipe greater than the pressure at the other end. This pressure difference creates force, which pushes the fluid constantly towards the lower pressure area.
Now that we know how to get a fluid flowing, let's look at what might slow down fluids in the pipeline.
How fluids flow and the amount of force required to move them is dependent on a range of factors like the diameter of the pipe, the viscosity of the fluid, and the roughness of the inside of the pipe, just to name a few. In fact, even the contact of the fluid with a smooth surfaced pipe can cause the fluids to slow down due to friction.
Gravity is another force that often affects the movement of a fluid travelling through a pipeline. When travelling downhill, gravity helps move the fluid, but when travelling uphill, gravity is working against the flow and must be overcome. And overcoming this force uses some of the pressure difference that's moving the fluid.
In order to overcome these forces, pumps for liquids and compressors for gases are positioned at regular intervals along the length of a pipeline to increase the pressure and manage the flow of the fluids in the pipeline. Pump and compressor stations are strategically located to help push the product through sections of pipeline where various forces act against the pressure difference.
Pumps or compressor stations are strategically located to help push the product through a section of pipeline where various forces act against the pressure difference such as going over a mountain range where gravity works against the pressure difference.
Pipelines are monitored constantly, 24 hours a day, 7 days a week, 365 days a year, by pipeline control centre operators. A variety of instruments and equipment provide them with information about volume, pressure, temperature and pump/compressor data that reflects the movement of fluids in the pipeline along its entire length. The pipeline control centre operator uses all this information to make sure the product is flowing and to determine if any further action needs to be taken.
Some pipeline control centre operators work in a control centre, where the information from sensors installed along the pipeline route is sent. One such system is called SCADA (Supervisory Control and Data Acquisition). The SCADA system is unique in that it allows pipeline control centre operators to remotely control pipeline flow by starting and stopping pumps and compressors. In this way, pipeline control centre operators can keep fluids flowing through the pipeline at the desired rate or, if necessary, control valves to completely stop the flow from a section of pipe.
The SCADA system also allows pipeline control centre operators to remotely control pipeline flow by starting and stopping pumps and compressors. In this way, pipeline control centre operators can keep fluids flowing through the pipeline at the desired rate or if necessary, control valves to completely stop the flow from a section of pipe.
