Masada’s CES OxyNol Process
The
OxyNol process involves five steps whereby the cellulose in municipal wastes in the form of hydrocarbons is converted into
sugar (primarily glucose). The sugar is subsequently fermented into alcohol, which is denatured to produce fuel grade ethanol. The
technology is outlined below.
a. Feedstock
Preparation
The facility is designed to
remove most non-cellulosic material from the waste stream creating a cellulosic rich feedstock needed for the chemical reaction
during hydrolysis. After inspecting for unacceptable/hazardous material the OxyNol process
includes an initial series of mechanical and manual sorting designed to remove unprocessable material and to separate recyclable
materials. The feedstock preparation system is designed as a traditional materials recovery facility (“MRF”),
a proven and widely used system. The MSW is unloaded from collection vehicles onto the tipping floor where large, bulky
items are removed. Conveyors move the remaining MSW to a mechanical separation system where the MSW is sorted by size
and the bulk of inorganic recyclable materials (primarily aluminum, ferrous and non-ferrous metals and plastics) are removed. The
resulting feedstock stream then enters a shredder and passes underneath a series of magnets and eddy current separators, which
remove the remaining aluminum and ferrous and non-ferrous material. The MSW waste stream is then substantially free of
metals, glass, plastics and other non-cellulosic material. The feedstock is then shredded to a smaller size, dried, fluffed
and moved to the hydrolyzation phase of the CES OxyNol process.
Sludge can be received in both liquid and solid cake form. The sludge undergoes an acidification
process where it is mixed with acid and acidic filtrate to kill pathogens, reduce solids, digest organics and generate CO2. The
material is then dewatered with recovered liquid reused in other areas of the CES OxyNol process resulting in cost savings
related to water purchases. The dewatered ‘acidified biosolids’ may then be used as boiler fuel
or mixed with lignin for sale as a renewable solid fuel.
b. Hydrolyzation and Cellulose Conversion
Hydrolysis is a chemical reaction, which breaks down the cellulose into a slurry containing sugars,
sulfuric acid, lignin and non-hydrolyzed materials. In the hydrolysis phase, the feedstock is treated with concentrated
sulfuric acid, which acts as a catalyst converting the cellulose and hemicellulose to glucose and mannose.
The resulting slurry is transferred to cooking tanks, where processed sewage sludge or
water is added to create the hydrolyzate containing the proper moisture content. The hydrolyzate cooks for a prescribed period
of time and then enters a separator to separate the liquid from the solids. The liquid portion of the hydrolyzate proceeds
to an ion exclusion unit to separate the sulfuric acid and the sugar. The remaining solids are composed of lignin and
non-hydrolyzed materials, which are used as fuel in the plant’s steam generator or sold as biofuel into such markets
as coal fired power generation.
c. Acid Recovery
A critical element of the CES OxyNol process is the
recovery of the sulfuric acid utilized in the hydrolyzation. The sulfuric acid/sugar solution from the hydrolysis phase
is fed into an ion exclusion acid/sugar separation unit to separate the acid and sugar solutions. The dilute acid solution
is reconcentrated through evaporation and is reused in the Process. The sugar solution is transferred to the fermentation
area.
d. Fermentation
The CES OxyNol process design incorporates a traditional batch fermentation process to convert the sugar to ethanol
and carbon dioxide. During fermentation, the sugar solution recovered from the separation phase is converted to ethanol
and carbon dioxide using the biological action of yeast. The carbon dioxide is collected and processed to commercial
standards for resale in an on-site unit.
e. Distillation
Distillation separates the ethanol from fermented mash and water to produce pure ethanol. The
fermented mash is distilled in a two-phase process. In the first phase, the ethanol is dehydrated by distillation to
approximately 90% concentration (180 proof). In the second phase, the ethanol is further dehydrated to 100% concentration
(200 proof) by using a molecular sieve. After the ethanol is transferred to a storage tank, it is denatured with gasoline,
converting it to fuel grade ethanol. The denatured product is stored until shipment.
