Booster pumping in series questions | Page 2 - Eng-Tips

Artisi - thank you. The other time you may need to run two in series is when the system curve changes, e.g. the end point of the system has a floating pressure. Sometimes one pump will suffice but at other times you need two in series to maintain the same flow or indeed any flow at all if the end pressure rises higher than the first pump head. Many many possibilities.

Pipeline booster pumps when the pumps are a long way apart can operate in both cases, e.g. you have a large hill in the middle, one pump generates enough head to get arrive at the base of the hill (but not enough to get over the hill) with a low pressure, enough to feed a larger head pump to generate enough head to get over the hill.

A different profile would mean that one pump at the start would be able to pump some liquid from one end to the other, but to get a higher flow you need a second pump half way along the line.

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Also: If you get a response it's polite to respond to it. Actually flow control VFD shouldn't be used for pumps. That's for gas systems. How do you control flow in a liquid piping system. Open or close an inlet valve, or open or close an outlet valve. VFD flow control only works for pump systems when there are no valves in the system. How often is that. Pressure control VFD works for pumps with, or without valves. You know what NPSHR you have to maintain to keep the pumps running properly, so use pressure control to VFD to keep suction pressure >= NPSHR. Speed up pumps when suction pressure is greater than NPSHR, and slow down (to a stop) when NPSHA drops below NPSHR. Combine with a maximum pressure trip, for when pressures rise due to outlet valve closure. If you get too much flow at the discharge close down on the outlet valve and back the pump up on the curve anywhere, at least until it reaches the high pressure trip. You could do that by an outlet flow control valve, but why try to control the pump with that? The pressure control settings are already doing that for you.

No. Back pressure at the end of a pipe is often supplied by static head alone. You don't always need a valve. In the case of a pressure controlled vfd without a pipeline end valve, the pumps will run at full speed, or whatever lower speed becomes might become the limiting speed such that suction pressure remains above NPSHR.

If you absolutely must control FLOW from the end of the pipeline (be sure you really do have to control flow), you might be able to do that with a pump somewhere within the system (this applies to flow or pressure control of that pump), but only if the system hydraulic characteristics allow it. If the pump's downstream pipeline goes over a high hill, then down again to a lower elevation, you will probably have to use a valve at the end of the pipeline, or your pipeline might not run full in the downhill segment. In such circumstances high flow rates might have enough head loss that the pressure loss per unit length acts the same as an end valve (kind of a distributed backpressure) and the design flow rate can flow without a valve holding backpressure at the pipeline's end, although at other lower flow rates some back pressure might be required at the end of the pipeline to keep the pipeline flowing full at any lower flow rate. If you don't mind pipelines not flowing full, then you wouldn't need a valve at the end of the pipeline.

In chemical plant work flow control is often required. That is not true in liquid pipelines where the business objective of the pipeline is to move as much product as possible in the fastest time possible. You have to first realize that flow control is inherently contrary to the business objectives of liquid pipelines. It is actually the same for gas pipelines, but due to the compressibility of gas, there is wide pressure variation with flow which can vary constantly with temperature and line pack so customer requirements are usually based on meeting specific flow rates at specific minimum delivery pressures. It is rarely necessary that liquid pipelines actually have a specific required delivery flow rate from the end of a pipeline. Most liquid transportation contracts are based on moving a specific volume (10,000,000 bbls of your oil and maybe 20,000,000 of somebody elses) within a given month. We are usually not interested in doing that at anything but the fastest flow rate possible within a given system. For that example a design flow rate might be 1,000,000 bbls/day, but if we could do it at 1,100,000, we just might want to do it. That flexibility to flow at higher capacity should not be limited by somebody's arbitrary flow rate setting. It should only be limited by the maximum flow rate when the pumps start hitting NPSHR. That is a pressure setting, not flow rate.

What do you need to consider when choosing a natural gas booster system?

Use Goals

This may seem like an obvious deciding factor, but taking the time to fully think through what you are trying to accomplish will help you make the best decision for the application. In your discernment, you may find that a natural gas booster system isn’t actually the best system for what you are trying to accomplish.

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Consider and outline things like

• what you need the system to do
• how it can be accomplished
• what resources are available to accomplish it

These factors will help you get a better idea of what the system will need to do to be successful.

If you aren’t well versed in this topic, engage an expert who is knowledgeable and can assist you in making a well-informed design decision. The complete systems once fully installed can be large, cumbersome, and hard to move. Making the decisions you make now even more important to the success of the project

Location

As they say, location is everything. Identifying exactly where the unit will go into the building or on the site is an integral component of picking the best system to purchase for the project. The location will also inform the power source types you can choose from. If you only have certain resources available on site that will impact which power sources are an option for you.

Contact us to discuss your requirements of gas booster pumps. Our experienced sales team can help you identify the options that best suit your needs.

Other things to consider are ease of access for maintenance staff and personnel. Taking this into consideration will alleviate problems down the line. When a machine needs maintenance or breaks down, the staff that needs to access it will thank you if they are able to easily access your equipment.

Life Cycle

The consideration of the life cycle is tied in with use. The life cycle of the system will vary depending on what it is being used for, how hard it is used, and maintenance. There are standard life cycle expectations with the caveats that everything is dependent on well you take care of the machines in the system.

Cost Effectiveness

The bottom line of every project undeniably ends up driving the selection process. The cost-effectiveness ultimately depends on the use, maintenance costs, life cycle, and rate of depreciation. Identifying the budget ahead of time and considering the overall cost-effectiveness of the system will be integral to selecting the appropriate system.

Next Steps

Seek out an expert to help you select the appropriate system for your project if you aren’t already working with one. Using the information above and the input of expert, find the perfect system for your project. The natural gas booster systems are an integral part of a well-planned solution to add pressure to your gas delivery.

Are you interested in learning more about pneumatic chemical injection pump? Contact us today to secure an expert consultation!