Fueling Candles into the Future Dustin Sinclair, CRM Mike Cales, Senior Research Scientist Atkins & Pearce, Inc.
Introduction • After last year’s NCA Show it was clear to Atkins & Pearce that alternative fuel sources (fuels other than pure paraffin) would start to become more prevalent in the market place. • Candle manufactures were urged to be flexible as changes in the market place occurred.
How Does This Affect Wick Manufactures? • As a leading wick manufacturer, Atkins & Pearce, needs to also be flexible to changes in the market. • As waxes and candle formulations change, the candle solutions will undoubtedly change as well.
Where to Begin? • In order to meet the needs of the marketplace we must first understand what those needs are.
Ask the Experts • We polled several of you the candle manufactures to see what was new in the industry.
What Types of Waxes are Being Used? • Candle manufactures polled said: • 65-75% of their candles contained some alternative wax. • Most of these alternative waxes were used in container candles
Are There Any Issues With the New Waxes? • The three highest problems identified in regards to the alternative waxes. • Reduced ROC • Diminished ROC in alternative waxes • Wax Pool Diameter • Harder to get wax pool to burn to edges with alternative waxes • Carbon heading • Increased carbon heading with alternative waxes
Do You See What I See? • We needed to quantify the observations we had seen and heard from the field.
Our Testing • Paraffin used as baseline • Used 2 different natural waxes • 50/50 blend (50 paraffin/50 soy) • 100% soy • Each of the three waxes tested had the same melt point (125-130 F) per MSDS sheets. • Each wick was tested in identical conditions.
Testing Cont’d • We collected the following data from each wick: • Flame Height (cm) • Wax Pool Diameter (cm) • Carbon Head (scale 1-5) • Wick Posture (clock) • After Glow (s)/After Smoke (s) • ROC (g/hr)
Our Findings • The data supports the claims made from the field. • Rate of consumption goes down, wax pool decreases, and carbon heading is increased in the alternative waxes.
Reduced ROC • Rate of Consumption refers to the amount of wax consumed by the candle during a burn. ROC is measured in grams per hour. • Reduced ROCs in alternative waxes has been seen in the field, and was verified by our testing.
Why the Reduction in ROC? • A significant difference in the viscosity of the waxes seems to be the major contributor to the differences in rate of consumption of the different waxes. • The fuel value of the wax will play a role as well. • Polarity may also have an affect on the rate of consumption
Viscosity • Viscosity of the waxes can play a major role in the wick’s ability to draw the wax up the wick. • The viscosity of the paraffin is 5.07 cP @ 90 C compared to the soy at 12 cP @ 90 C.
Heat Energy of Fuel • Heat energy, measured in J/g, tells us how much energy is produced by burning one gram of a given fuel. • Atkins and Pearce used a simple experiment to determine the heat energy for the three waxes we were evaluating.
The Experiment • Using the setup seen in the picture we tested the three waxes. • We used the same wick, over the same time interval.
Results Cont’d • Using the equation Mass of Wax*Fuel value=Mass of Water*Specific Heat of Water*Change in Temperature of Water we were able to determine the fuel value of each wax.
Polarity • There is also a the idea of polarity to consider. At this time we have no hard data to share, but we would like to spend some time on the notion that polarity could be having an affect with the natural waxes. Paraffin wax is non-polar, thus historically we have not had to consider polarity when talking about candles.
Polarity Cont’d • Cotton which is a cellulose material that is polar and the natural wax is also polar could have a natural attraction for each other slowing the rate at which the wax is carried up the wick.
Think of it as a Highway • Paraffin because it is non-polar rides in the fast lane as it goes up the wick. • The natural waxes on the other hand are slowed down by their attraction to the wick.
Reduced Wax Pool Diameter • A decrease in wax pool diameter in the alternative waxes was reported from the field, and was confirmed by our data.
Why the Reduction in Wax Pool Diameter? • Differences in a few key areas could be contributing to the decrease in the wax pool diameter: • Latent heat of fusion • Fuel value of waxes • ROC
Melt Profile for the Waxes • Using a DSC (Differential Scanning Calorimeter) we were able to determine the melt point of the waxes, as well as, their latent heat of fusion. • Latent heat of fusion refers to the amount of energy it takes to convert one gram of solid material to its liquid form.
Summary of DSC Results • Soy wax starts to melt at a much lower temperature than paraffin. • It takes one and a half times more energy to melt a gram of paraffin when compared to the soy.
Conclusions of DSC Testing • With the data that from the DSC we would actually anticipate soy wax to have a larger wax pool than the paraffin. However, as displayed by the bar graph earlier this is actually not the case. • We have to ask ourselves what other factors are coming into play when we look at the wax pool.
Other Factors • When looking at the data it is easy to notice the differences between the wax pool diameters, however, it is also important to look at the depth of the wax pools and the volume of wax in the pool.
Wax Pool Depth • The soy wax pool is almost two times as deep when compared to the depth of the paraffin wax pool.
Summary • Although the wax pool may be smaller in diameter with the soy wax, the total volume of molten wax in the pool is significantly higher. • This helps to explain the DSC results.
Fuel Value/ROC • The fuel value predicts the wax pool diameter. • The heat given off by a candle is directly related to the amount of fuel it can bring up the wick. • As the rate of consumption increases the wax pool diameter will increase.
Increased Carbon Head • Reports from the field indicated there to be an increase in the amount of carbon build up on the wick when using alternative waxes. • Our data confirmed these reports.
How Does a Carbon Head Form? • When unburned fuel collects back onto the tip of the wick it forms a build up we call carbon head. • Some believe that carbon heads are actually extruded from the wick, however, as the next few slides show it is actually a reattachment.
Why the Increase in Carbon Head? • We believe this is directly related to the fuel value of the wax being burned. The lower the fuel value of the wax, the higher the chance for incomplete combustion. • Polarity of the wax.
How Can the Wick Help? • Solutions will vary from candle to candle, and there is no “miracle” wick. However, there are ways to help with some of the issues we have talked about.
The Wick and ROC • Given the nature of the natural waxes we experimented with there are only a couple of wick answers: • Use a larger wick • Use a wick with a more open construction • In candles with higher amounts of stearic acid a treatment to fight against acid attack may be needed.