Thermal fluid heating systems have revolutionised process heating, making the large, energy hungry and heavily manned plant rooms a thing of the past for the majority of industries. Whereas a plant room based around mammoth fire tube steam boilers required lots of space for equipment and was relatively complex to use and maintain, thermal fluid heating systems are compact, easy to use and, offer an overall saving in energy that is hard to beat says Babcock Wanson MD Chis Horsley
Thermal fluid heating is based on a similar principle to a domestic hot water system. It consists of a heater connected to carbon steel flow and return pipework which can provide heat to one or more users or systems. Instead of water running through that pipework, a thermal fluid – most often a simple industrial oil – is used as the heat transfer medium.
One of the key factors in achieving very high levels of system energy efficiency is the ability of a thermal fluid system to work at high temperatures (up to 350°C in standard form) in a simple closed loop. When compared with a steam system this means no change of state of the fluid so no condensate and therefore no flash steam losses, no blow down losses or make up water required, no effluent discharge and completely corrosion free without the need for expensive chemical treatment. It all adds up to substantial savings for the operator.
Using thermal fluid as opposed to water has other key benefits including removing the problems caused by scaling and changes to ambient temperatures, as well as improved safety. In a water system, pressure rises as a function of temperature: the higher the temperature, the greater the potential for problems within the system and the higher the system’s materials cost. Not so in a thermal fluid system as there is little relationship between temperature and cost so the fluid doesn’t have to be kept under pressure (other than the very small pressure of the circulating pump). This also brings significant advantages in the sizing and cost of heat exchangers.
Size is another major factor in the uptake of this technology. A thermal fluid heater is very compact and needs no specialist site work meaning it can usually be sited in the most convenient location, often close to the user, meaning substantial savings in specialist plant rooms and distribution pipe work.
With Babcock Wanson’s TPC1000B thermal fluid heating system, for example, between 20-50 per cent energy savings can be made when compared to the transfer of the same amount of heat using traditional steam boilers. The system precisely matches fuel input to plant energy requirements for high efficiency. With lower energy input demand also comes lower total exhaust emissions, so there are also environmental benefits.
It’s also a very flexible system as different thermal fluids can be used to meet specific process heating requirements. Of course, not every industrial process is suited to thermal fluid heating systems. There are a number applications – most notably where both direct and indirect heating are required simultaneously – where steam generation is the only viable solution and the technology has advanced dramatically to keep pace with changing requirements. However, thermal fluid heaters have outpaced steam generation in the majority of process heating applications and, with their energy efficiency, ease of use and compact size, it’s not difficult to see why.
Babcock Wanson
T: 020 89537111
