By Brent Chrabas | December 09, 2014
In collaboration with Tactical Fabrication of Dublin, Georgia, and Novozymes of Denmark, a novel biodiesel production technology developed by Viesel Skunk Works LLC will soon be offered commercially. The innovative system features a continuous flow enzymatic reaction process that also eliminates sulfur from biodiesel when low-grade feedstocks such as brown grease are used. Today, the dominant method of producing biodiesel is through batch reactions, which can be considered inferior due to lower productivity, larger variation in product quality, and more intensive labor and energy requirements.
The development of continuous reactors for biodiesel production using enzymatic catalyst has been discussed for a long time, yet there is no saleable biodiesel produced from commercial biodiesel plants with a continuous enzymatic reactor. Most importantly, reducing the sulfur to 15 ppm in biodiesel when the feedstock contains up to 10,000 ppm of sulfur compounds is currently one of the biggest technological challenges for biodiesel producers.
The patent-pending technology Viesel Skunk Works LLC developed is a design of several continuously stirred tank reactors (CSTRs). In this system, only a very low dosage of the liquid Novozymes enzymatic catalyst needs to be added to the reactor. It provides for a very complete reaction with the potential of using fewer enzymes than in single-step batch systems. Moreover, this is the most economical process of biodiesel production in the industry producing a 99 percent conversion yield with any kind of low-grade feedstocks, such as waste cooking oil, animal fats, brown grease and more. The initial investment is materially lower than other conventional methods and the fully automated process guarantees production of low-cost biodiesel.
The benefits of using the Viesel Skunk Works continuous enzymatic process for biodiesel production are as follows.
Several simple CSTRs and skid-mounted injection pumps are the main components of the continuous system. Each CSTR can be easily switched to batch operation mode in the case of accidental interruption of the continuous mode. Intensive caustic washing in the current enzymatic process for free fatty acid removal is overcome by using simple resin columns, which fully convert FFAs to corresponding esters. The problem of sulfur contamination by the low-grade feedstock was solved by introducing a new, simple, patent-pending distillation system to remove the sulfur compounds from the final biodiesel product. Furthermore, this continuous enzymatic process can be outfitted with automated in-line analysis systems, which allow biodiesel quality to be assured in real time.
The Viesel Skunk Works continuous process is stable, with maximum biodiesel productivity approximately five times faster than the conventional batch process. The process can be brought up to any rate of production rapidly by automatically adjusting flow rates and quantities of reagents needed while targeting the requisite enzyme dosage using the online digital control system. Product meeting specifications set forth by ASTM D6751 can be obtained in a shorter time due an advanced mixing process.
Lower Capital Investment
Moderate reaction conditions, more efficient mixing technology and smaller plant footprint guarantee a much lower capital investment in the continuous enzymatic process. Furthermore, in contrast to utilizing a high-cost immobilized enzyme, which may perish with mishandling, flexibility in acquiring liquid phase, homogeneous, single-use enzymes as needed is extended to operators of this process. The technical challenge of reducing sulfur levels from up to 1,000 ppm in biodiesel to a maximum of 15 ppm to meet strict ultra-low sulfur diesel (ULSD) requirements was also resolved by the Viesel Skunk Works team by offering a modular component capable of sulfur separation. This final component to the continuous enzymatic process makes the production of high-quality biodiesel perfectly continuous without requiring any expensive hydrodesulphurization processes or intermittent addition of hazardous organic solvents or additives in the process when using cheap, high-FFA feedstocks.
The largest benefit of using the Viesel Skunk Works continuous enzymatic process is being able to adapt its use to a variety of low-cost, high-FFA, cheap feedstocks such as brown grease. Feedstock costs are recognized as the highest variable cost in the production of biodiesel accounting for up to 80 percent of the material costs associated with making a gallon of biodiesel. This process allows the use of materials that may be as much as 50 percent cheaper than conventional feedstocks, which have limited use in traditional biodiesel processes.
The revolutionary continuous enzymatic process being demonstrated by Viesel Skunk Works LLC at its world headquarters in Stuart, Florida, has been progressively designed to streamline production with reduced start-up costs. Its processing capabilities that make use of cheap feedstocks not ordinarily available for traditional biodiesel processes afford plant operators the ability to better manage production costs. The culmination of research efforts embodied by the Viesel Skunk Works Continuous Enzymatic Process make certain that biodiesel will persevere as a low-cost alternative to its petroleum counterpart amid any market conditions.
Author: Brent Chrabas
Quality Engineer, Viesel Fuel LLC
Editor’s Note: This article was written exclusively for Biodiesel Magazine by Viesel Fuel LLC.