Pipe Flow Wizard
Pipe Flow Wizard, from www.pipeflow.com, allows you to solve gravity flow problems for a variety of fluids. The program solves for one of four variables: 1) Pressure, 2) Pipe Diameter, 3) Pipe Flow, or 4) Pipe Length. In the screen shot below I’m giving an example of real problem. The problem is described below the screen shot.
Pipe Flow Wizard Screen Shot
In a refinery there are large storage tanks for holding crude oil. As the crude oil sits in these tanks separation begins to take place in which water pumped in with the crude begins to settle to the bottom of the tank. In reality, this is an oily water moving to the bottom of the tank with the crude oil on top of the water. A common practice is performing tank water draws of BS&W or bottom sediment and water. The tank water draws are drained to the wastewater treatment plant in the refinery. What is not, perhaps, well-known, is that this BS&W waste stream carries a highly variable organic component that, fortunately, the microorganisms in the biological reactor love. This, in itself, is a good thing, as compared to this waste stream being inhibitory or outright toxic. But there is a downside to the BS&W and that is, because it is so readily oxidized by the bacteria, if too much BS&W flow goes to the wastewater plant the bacteria will go after the organics in this waste stream so quickly that they can easily exhaust the oxygen supply to the biological reactor. And once the oxygen is exhausted odor becomes an issue along with a decrease in microbial activity.
So the simple problem to be solved, a gravity flow problem, was to estimate the maximum possible flow out of the crude storage tank using the assumption that an operator is likely to open the valve on a 4-inch line to a “full-open” position, rather than a “partially-open” position, so he doesn’t have to stand there for several hours waiting to drain the BS&W. If you look at the top right box in the screen shot below, with the yellow background, you can see the assumptions made in solving this problem. The pipeline is made of steel, 4-inches in diameter, with a 30-ft drop over 2,500 feet of pipe run, with a crude storage tank level of 30 feet (head). The result is shown to be 205 gallons per minute (gpm), the maximum possible flow rate. If we do oxygen uptake rate testing on the BS&W waste stream, which we’ve done, we can then calculate the the oxygen demand from this wastewater source and add it to the oxygen consumption of other waste streams to determine if there is sufficient oxygen generation capacity in the biological reactor. If we know that the BS&W exerts a very high oxygen demand and that its full flow of 205 gpm, when combined with over 2,000 gpm of other wastewater flow, will exceed oxygen input, it helps in making the decision to put an orifice plate in the 4-inch to reduce the maximum flow rate out of that line.
There is something else to be observed in the screen shot. Look closely at each of the four panels, at the liquids selected. The top left panel, in grey, shows the fluid to be SAE 30 oil. The bottom left panel with a green background shows sea water as the fluid. We just solved for water in our example. The panel on the bottom right with a bluish background has milk for its fluid. There are a number of built-in fluid options but if you don’t see one that represents your fluid of interest you can add your own fluids to the database, which is easily done and makes the program that much more flexible in the range of fluids it can handle.