Selecting A Circulation Heater For Biodiesel Manufacturing

Alternative and environmentally conscious energy sources are a growth industry. And that’s not just limited to Tesla’s and solar panel roof tiles. One of the biggest areas of growth in the energy sector is in biodiesel manufacturing.

Biodiesel HeaterIn part, this is helped in the USA by a 2017 bill to modify the biodiesel tax credit. The bill provides a $1-per-gallon production credit for biodiesel produced in the USA. With the tax credit slated for 3 more years, there is no expectation of a slow in production over that time.

This will help meet the increasing national and international need for diesel alternatives. In Brazil, for instance, half the population uses biodiesel.

The production of biodiesel comes with it’s own set of challenges. These require the right equipment for an efficient and cost-effective process. We discuss the role of circulation heaters in biodiesel manufacturing. And how to pick the heater which best suits your needs.


The role of circulation heaters for biodiesel production

Biodiesel is created through chemical reactions between lipids – from vegetables or animal fats – and alcohol. The pressurized liquid needs to be kept circulating with a consistent temperature. This maintains the appropriate viscosity. For this purpose, circulation heaters are ideal.

The best choice for preheating biofuels is a circulation heater. They offer direct immersion in the fluid, for fast and efficient heating. Also, you can add thermocouple sensors to prevent overheating.

In addition to preheating biodiesel fuel oil, circulation heaters help with:

  • Increasing temperature
  • Maintaining pumping viscosity
  • Closed loop heat transfer systems
  • Freeze production


Challenges of heating biodiesels

Preheating biodiesel comes with its own specific challenges. Biodiesel has greater caustic characteristics than traditional fuel sources. As a result, the equipment has a much higher failure rate. That means more frequent replacement, more maintenance, and lost/damaged product.

The caustic nature of the medium leads to premature rusting and/or deterioration of equipment. This includes the steel sheath of the circulation heater.

As well, the caustic elements make maintaining flow for biodiesel more challenging than other mediums. This can lead to a buildup on top of elements. Which results in shorter lifespans for circulation heaters.


Addressing the challenges of preheating biodiesel

Wattco has success managing the challenges of heating biodiesel. This was accomplished using lab work and expert experience to help a biodiesel manufacturer in Oklahoma. Wattco analyzed the biodiesel, and identified as the source of corrosion causing the failure of industrial heaters. With this knowledge, Wattco was able to redesign their electric circulation heater to address this specific challenge.


Circulation heater materials for biodiesel heating

The first problem addressed was the corrosion of circulation heater elements. Altering the medium was not an option, so they focused on changing the heater materials.

The original construction used a steel sheath. This was replaced with a stainless steel 316 sheath. This type of steel is more resistant to corrosive elements. As a result damage was reduced so the need for maintenance and repair was also reduced.

The thickness of the sheath wall was also increased. This improves the structural integrity and minimizes the risk of failure. The elements now last longer. This reduces overall biodiesel manufacturing costs and preventing stoppages in production.


Biodiesel heating watt density

The caustic nature of biodiesel also requires an adjustment in watt density. Vegetable oils can tolerate high sheath watt densities. But biodiesel can damage equipment if the watt density is too high. Extreme watt densities can cause the medium to carbonize or overheat. Resulting in damage to the equipment or solution.

By reducing the watt density to 25 Watts per inch2 the life expectancy of the circulation heater is increased.


Increasing circulation heater flow in biodiesel applications

To improve circulation we changed the layout of the heating elements. Hairpins were separated and a centre pipe and baffles were added. The result was a better flow that prevents a buildup on the elements.

This improves flow rate and extends the lifespan of the circulation heater.


Benefits of electric circulation heaters in the biodiesel industry

Electric circulation heaters are the preferred method of heating biofuels. They offer flexibility and customizability in construction, so they address the specific needs of the medium. For example, choosing stainless steel 316 sheaths when heating a caustic solution. As well they offer:

  • Efficient heat transfer
  • Lower operational costs than fossil fuel powered heaters
  • Longer lifespans than fossil fuel powered heaters
  • High pressure ratings (up to 25000 PSI)
  • Explosion proof housings
  • A selection of housing options
  • A number of available thermo sensors and controllers

Picking a circulation heater for biodiesel applications

For biodiesel, there are two options for circulation heater – flange or screw plug. Circulation flange heaters are easy to install and come in any configuration required. They are safe, stable, durable, and highly efficient. They heat large volumes and can reach temperatures as high as 1,200 degrees.

The lower Watt density ideal for biodiesel manufacturing can make screw plug circulation heaters a great choice. These heaters screw directly into the tank and have a high degree of control. They are best for smaller applications.

Every application is a little different with variations such as size, climate, and medium. A Wattco representative can help you determine the best circulation heater for you. Contact us today to request a quote or more information.