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How IIoT Data Can Improve Heat Exchanger Performance

 How many heat exchangers are running in your plant? Dozens? Hundreds? A tougher question: How efficiently are they running?

Maybe you know the answer to the efficiency question, but based on our collective experience with countless plants, few operators can quantify performance for more than their most critical and expensive heat exchangers, and even that’s a stretch in many cases. This doesn’t have to be the case today, given the availability of monitoring equipment able to use IIoT-supported networks.

This is the main point of my article in the March 2020 issue of Process Heating: How IIoT Data Can Improve Heat Exchanger Performance. As you know, heat exchangers come in every imaginable configuration and size, but there are underlying similarities.

Heat exchangers depend on complex internal geometry to provide a large amount of surface area. This can create convoluted internal flows, small passages prone to plugging from debris or fouling due to solid deposit accumulations. Such plugging and fouling reduce heat transfer efficiency and can limit throughput when severe enough. These problems drive up operating costs while capacity goes down, which can reduce the overall process performance. If cooling capacity is critical for a potentially hazardous exothermic process, process safety could be threatened.

Estimates suggest that across refineries in North America collectively, heat exchanger inefficiencies cause annual losses in the billions of dollars. Since you want to save money, ask yourself, how do you know when such problems are forming? Few heat exchangers have sufficient monitoring equipment to collect much useful data. Fixing this deficiency is where the IIoT comes in.

Determining how efficiently a heat exchanger is operating depends on measuring what it is doing. This can be accomplished with instrumentation that includes, at a minimum, devices measuring:

  • The process fluid temperature differential (inlet compared with outlet) and flow.
  • For liquid-to-liquid designs, the transfer fluid temperature differential and flow.
  • For air-cooled designs, the cooling air temperature and flow.

Installing these instruments, today is much easier than it used to be with traditional wired approaches. Pervasive Sensing Solutions using WirelessHART, which can interface with IIoT-based applications, simplify the task and make it far less expensive.

Of course data alone doesn’t help very much without appropriate analysis, and this is another area of vast improvement provided by tools such as Emerson’s Plantweb Insight Applications. When fed by data from WirelessHART instruments, Plantweb Insight offers instant visibility to key assets, including heat exchangers, enabling you to make better, faster decisions to digitally transform your operations. Engineered with machine learning-based asset models and analytics, this solution easily integrates with existing infrastructure and features intuitive navigation across a web-based visualization environment.

These types of applications — combined with new WirelessHART instrumentation options — provide capabilities that previously have not been available. With IIoT and wireless technologies, continuous monitoring is practical and less expensive to install and operate. Such pervasive sensing combined with analytics can reduce unplanned production losses, cut maintenance costs related to heat exchanger cleaning and reduce energy use.

So where are you on the efficiency knowledge scale? Do you have a good handle on things, or do you wish you knew more? You can tell others about your situation and experiences at the Emerson Exchange 365 community forum, a place where you can share ideas and experiences with others facing the same challenges. It’s a site where you can communicate with experts and peers in all sorts of industries around the world. Look for the Wireless and Essential Asset Monitoring Communities, plus other specialty areas for opportunities to provide input, suggestions, and answers.

1 Reply

  • Heat exchanger monitoring is great. In some applications you can see the fouling by observing the temperature control valve that controls cooling water or steam: the more opened, the more fouled.

    However, many heat exchangers are in a service where they just transfer heat from one product that is too hot (e.g. to condense a gas to liquid) to a product which is too cold (e.g. crude / feed). In this case there is no control valve hinting there is fouling. Now you need to monitor.

    It is also common for heat exchanger packages to have multiple bundles. In this case, how do you know which bundle is fouling? Now you need to monitor them all.

    Most plants are going for digital transformation of how the plant is run and maintained. However, they do not want IIoT (cloud computing and internet connection). Most plants prefer to do their digital transformation on premises (say "on-prem" if you want to sound like an expert) using edge computing. That is, the analytics runs on a server within the plant and an internet connection is not not required - making cybersecurity a little easier to manage.

    Learn what other plants are doing from this essay:
    www.linkedin.com/.../