What's new in production

In my October column, I introduced you to the interesting world of functionalized surfaces. These are nano-scale treatments to surfaces that makes them perform certain functions. I introduced two of the advantages of having surfaces “phobic” to oil- and/or water-based fluids: corrosion protection and flow enhancement.

This month, I would like to expand my discussion to include another application for functionalized surfaces—and a new type of nanotechnology.

Heat exchanger efficiency: Never, in all my days, have I ever told anyone that I wanted a heat exchanger for Christmas. NEVER! They are usually inefficient and require almost constant maintenance. But they are a necessary part of life in this business—and many other businesses as well.

Steam condensers present a unique opportunity to improve the rate of heat transfer. A study published by MIT in 2013 discussed the phenomenon of how the “wetting” of condensation tubes by condensed water actually slows heat transfer. The thin film of condensed water that “wets” a condensation surface actually acts as insulation, and it slows the heat transfer process. Making the cooling surface hydrophobic results in the condensed water dropping off (or jumping off) the surface, thus improving the efficiency of the heat exchanger.

Oceanit Laboratories in Hawaii has developed a product for use in power plants to enhance heat transfer efficiency and to prevent corrosion and fouling. Their HeatX product for heat exchangers has enjoyed several successful pilots, including the Kahe power plant on the island of Oahu. HeatX can be applied at thickness of <2 mil. Oceanit  has seen improvements in heat transfer rates of up to 20x over bare exchanger substrate. They also have seen lowered back pressures, due to the reduced friction losses. There is also reduced corrosion, because the fluid that would cause corrosion is repelled by the condensation surface. Additionally, HeatX prevents the deposition of micro-organisms, thus preventing biofouling. This greatly reduces the frequency of maintenance interventions required to keep heat exchangers operational. Figures 1 & 2 show the condition of heat exchanger tubes after 6 months service, with and without HeatX applied.

Fig. 1. . Barnacles growing on the surface of a seawater-cooled heat exchanger surface after 6 months in service.

Fig. 2. No marine growth on HeatXtreated portion of a seawater-cooled heat exchanger surface after 6 months in service.

In addition to the operational and economic benefits of “well-behaved” heat exchangers, there is a total plant decarbonization implication, as well. Obviously, better heat exchanger performance leads to better overall plant efficiency, which reduces fuel consumption, and reduces GHG emissions.

HeatX is functional up to 400°F (204°C). Further information can be found on Oceanit’s HeatX website  at: https://www.heatxsurfaces.com.

NanoFluidics.Now, let me whet your appetite by looking at another technology that is making its way into the field—NanoFluidics. NanoFluids are fluids that contain nano-sized particles of specific materials that somehow enhance the ability of the fluid to perform a specific function. Note that nanoparticles will not settle out of water; they remain suspended (not in solution) indefinitely.

TCT Nanotech, headquartered in Italy, makes a line of these products. Their Nanotech HT line of products is designed for closed-system heat exchangers. These nanoparticle additives increase the Thermal Conductivity of the cooling or heating medium (by up to 18%). Thermal Conductivity is the ability of a fluid to conduct heat. This should not be confused with Specific Heat, which is the ability of a fluid to carry heat from one place to another. It still takes 1 BTU to heat one pound of water by 1°F. In a heat exchanger, increased Thermal Conductivity means that the heat being transferred into (or out of) the fluid can travel into (or out of) the fluid more quickly. This results in a more efficient heating (or cooling) of the fluid, thus increasing the efficiency of the heat exchange process.

Sound a bit far-fetched? It is very real. From September 2017 to August 2018, TCT Nanotech trialed their HTC Compact® in the HVAC/R system at the New York Botanical Gardens: Pfizer Plant Research Laboratory in the Bronx, New York. During that period, the facility realized a 14% drop in electricity and 8% drop in natural gas consumption. This savings in fuel use, fuel costs, and GHG emissions was due solely to the increased thermal conductivity of the water-based cooling medium. More information can be found on the TCT Nanotech website
(https://www.tctnanotech.com/).

Nanotechnology is not a buzz word. It is very real and has very real, economic potential in the oil & gas industry. More will be revealed.