To create a pipeline model in a spreadsheet, choose File | New and follow the steps shown. To open an existing pipeline model, choose File | Open and choose the name of the pipe data file from the resulting screen. All pipe data files are designated with a file name extension of.TOT. Choosing the included sample pipeline MyPipe001 will display the data in the spreadsheet as shown below. This pipe data file contains all the information for the sample problem, described in the User Manual.
If a new pipeline data file is to be created from scratch, choose File | New and a blank spreadsheet screen will be presented for entering the pipeline data. After entering the pipeline data, save the file by selecting File | Save from the menu bar.
For further explanation on creating and editing pipeline data files, refer to the User Manual.
Each column in the spreadsheet is for a specific data for the pipeline. Each row represents a specific location along the pipeline. As the cursor (arrow) keys are moved around in the spreadsheet cells, the status bar at the bottom of the screen briefly describes the information to be entered in each cell. After each numeric entry, press Tab key or the arrow (cursor) key. The first column is for the distance measured from the origin of the pipeline, such as mile post. Each subsequent location of the pipeline is measured from the beginning of the pipeline and hence the first column is the cumulative length of each point on the pipeline measured from the beginning (where the inlet gas flow originates), also designated as mile post location (m.p.). Note that unlike other hydraulic simulation models, the distances are cumulative and not pipe segment lengths.
The second column is for the elevation of the pipe at that mile post location, measured above some datum, such as sea level. The third, fourth and fifth columns represent the pipe outside diameter, pipe wall thickness and the internal pipe roughness at this location. The pipe diameter, wall thickness and roughness entered at a specific location represent those for the pipe segment downstream of that milepost location. Thus, if the first two milepost locations are 0.0 and 45.0, as shown above, the diameter, wall thickness and roughness entered at 0.0 milepost are for the pipe segment from 0.0 to the 45.0 location. The diameter, wall thickness and roughness entered at milepost 45.0 are for the next pipe segment starting at milepost 45.0. Accordingly, for the very last milepost location, 420.0 (the last data row of the spreadsheet) the diameter, wall thickness and roughness entered should be a duplicate of the immediately previous location (milepost 380.0), since there is no pipe segment downstream of the last milepost. The pipe delivery pressure at the end of the pipeline and the minimum pressure required are input in the main screen. If a minimum delivery is to be held at the pipeline terminus, click the check box shown.
The next column entry is the maximum allowable operating pressure (MAOP) for the pipe at that milepost location. If you double-click with the cursor in the cell containing the MAOP, a data entry screen opens up. This screen can be used to verify or calculate the MAOP of the pipe. It also calculates the hydrostatic test pressures for pipe hoop stresses of 90% and 100% of the specified minimum yield strength (SMYS) of pipe material.
Note that for the pipeline profile, a maximum of 1000 points (or nodes) are allowed in the pipe data screen.
The pressure drop for each segment is calculated using the General flow equation and using friction factors calculated from Colebrook or AGA equations. Other flow equations, such as the Panhandle A and B, Weymouth, etc. are also available as options. A total of eight pressure drop equations are available to choose from. Pipeline elevations are also taken into account in determining the pressures along the pipeline.
Additionally, certain global data such as pressure drop formula, compressibility factor calculation method, maximum gas velocity, pipeline efficiency and gas specific heat ratio are also input. All input data are saved for the specific pipeline in a TOT file which is similar to an XML format. Thus a pipeline named Compton to Harvey will have all data stored in a file named ComptontoHarvey.TOT.
Entering Gas Properties, Pressures etc.