March 4, 2020

When Condensate Pumps are Needed In the Steam and Condensate System

My name is Kelly Paffel, Technical Manager for Inveno Engineering, LLC located in Tampa, Florida. We are a domestic and international engineering firm specializing in steam and condensate systems. Our presentation will review “If Condensate Pumps Really Needed?” and when needed in a steam and condensate system.  A large percentage of the time (25% or greater) industrial plants are installing condensate pumping units in the steam and condensate system when a condensate pumping unit is not needed, therefore a waste of money and a reliability operational issue.

One way to correct condensate pumping issues is not installing or removing condensate pumps when the units are not needed in the system. Many times, steam components are put into a steam system, and the supplier states, “Oh, you need a condensate pump,” and we don’t even ask, “Why do we need a condensate pump?” And then as you can see this in the picture, then we have steam from the flash steam coming out and pumping issues, which is a quite common problem with the steam and the condensate system.

Condensate pump installations. A lot of components are put into the system, as I was talking about, and then we add a condensate pump. And the thing is this is a common application here, where we have a shell and tube heat exchanger coming down here through a steam trap and then into a condensate return system. And the question is do we need a condensate pump there to get the condensate back to the system? It depends on several variables in the system, which we must look at as a system, not just a single component.

Well, in looking at the condensate system, we must do the classifications, and there are four classifications of a condensate system. One is a standard condensate system, which is gravity or atmosphere condensate line pressure maintained at or close to zero PSI, which is very important on several process applications. The other one is low pressure, one to 15 PSI, and today’s technology is pressurized condensate systems, which are operating 16 to 99 PSI for medium pressure, and high pressure we’re over 100 PSI.

Now, a condensate tank with a pump system can be put into any one of these systems, depending on what we’re trying to accomplish. So, on a gravity system, a zero PSI or low pressure one to 15 PSI. The thing with this type of a system, let’s say up here we have a process that modulates here and the monitoring the steam to the process can be as low as zero PSI going into the process. Then the condensate needs to come down by gravity to a pumping unit, because we must deliver it either back to the boiler plant or back to the deaerator. And with those types of processes, they cannot tolerate any pressure.

Now, as a standard condensate system, as I was talking about, steam is given to the processes and then would come back to the condensate pump here, which is pumping back into the deaerator. This system here does need to have a condensate pump put in and then deliver the condensate back to the boiler plant. And the same thing as when we put in an atmospheric tank system that we must understand we’re going to lose flash steam to the system.

The standard condensate systems with a condensate pump, the thing is that in range you’re getting assessments, and their percentage is about 25% of the condensate pumping units are not needed. It’s not uncommon for us to come in and eliminate condensate pumps. One we just did was 18 of the 24 condensate pumps were eliminated. They didn’t need them.

The thing is, a condensate pump is needed when the system drain device is a steam trap or control the outlet pressure here, which is [inaudible 00:04:27] here exceeds the outlet pressure. So, the thing is that if P3 is greater than P4, then you can deliver condensate back into the condensate return system without a need for a pump. And there’s a multitude of applications out there that can deliver the condensate back to great distances without having a pump. Example one would be tracing systems in chemical refinery or other applications.

The other thing that we must deal with in a standard condensate system is pressure in the line. All condensate lines unfortunately are operated with back pressure due to the following: a lot of issues with undersized lines, people not sizing the lines properly. The other thing that happens is neglect of steam traps, blowing steam into the condensate return line, the steam trying to expand 1600 times, and it’s not able to and it creates pressure in the return system.

With those issues, there are need for areas to have condensate pumps. So, the thing is that we must look at it as a system. And the thing again, as when we were talking about before, if the inlet pressure is greater than the outlet pressure, life is good. If the outlet pressure here can be greater than the inlet pressure, then you need a condensate pump system.

Now, in pressurized return systems, because we have high pressure, the process applications which are shown here and the pressure is great enough, then we can go into a pressurized return system and recover the flash steam. Now, depending on distances from the boiler plant, we might have this tank running at 50 PSI and then pump the condensate back to the deaerator operation or possibly pump it directly back into the boiler room. That is pressurized system.

But the thing about any system is that we want to return the condensate as hot as possible. So, we contain the flash and the sensible energy in the condensate and deliver it to areas that we can recover it. That increases our steam system thermal cycling efficiency, which is a benchmark today that we must be looking at.

Now, a pressurized system or any part of the system, the system can operate under pressure. So, the thing and with these systems here that we can have pumps located down in here to help us deliver the condensate back. There are other segments in the systems that here we are not using a pump to deliver back. So, it depends on the system, and you must look at a system if you really do need a condensate pump or not.

The thing with condensate pumps, we must have reliability, and the reliability is having industrial pumps which have a cost to them, of course. And we want operation of 15 years. We want no failure of any pump, specifically a condensate. I mean, a condensate pump is its water. I mean, simplest thing that we do is we pump, so it should last you 25 years. But then it becomes in the design of the system, the tank designed correctly, the pumps with correct NPS [inaudible 00:08:16].

In a proper system put in, there is a need for it. And my point is understanding it’s a system and we must look at it as a system to make sure that you do really need a condensate pump.

So how to get started. Understand the current system. Roadmap for changes or implement changes, and to document the success of the program.

This is our contact information, and we do steam system assessments, engineering, steam balance and steam system performance assessments. And one of the big factors that we support our customers is training, specifically different parts of the steam system. We also do long-term impacts for upgrades to the system, process change, improve reliability and safety, which is our focus on all our systems.

If you have any questions, please contact. This is our contact information and have a great day.