Hydrothermal Cleanup Renewable Diesel Pretreatment
Water. Temperature. Pressure. Turbulent Flow.
Hydrothermal Cleanup (HCU), US Patent 10,071,322 B2, is ARA’s novel and patented pretreatment process that offers several key advantages over traditional pretreatment processes, producing a clean stream of glycerides and free fatty acid products from lower cost waste feedstocks. HCU consists of a continuous, refinery-friendly, single-step process that utilizes common refinery equipment such as pumps, heat exchangers, and a hot oil furnace or refinery high-pressure steam. The HCU process requires only water, heat, and pressure to remove metals and other inorganics from most common feedstocks.
Utilizing turbulent flow at high temperature and pressure, HCU provides thorough mixing of fats, oils, and greases and water and close contact of the molecules during its short residence time. The single step, continuous process removes metals (including organically bound metals) and other inorganic contaminants while acidulating soaps and hydrolyzing phospholipids into fatty acids and phosphate salts.
HCU is a Pretreatment Process that Utilizes Conventional Refining Process Equipment and Generates No Solid Wastes
- HCU uses pumps and heat exchangers typical to petroleum refineries
- HCU is a continuous flow process
- Feed stock particulate filtering is only necessary to protect pumps
- Centrifuges are not required for separation of the clean lipid product and water
- Diatomaceous earth and bleaching clay filtering are not required
- Activated carbon filtering is not required
- Effluent water can be treated by conventional wastewater treatment processes
No Mass Loss
- HCU preserves nearly 100% of the feedstock – including the lipid portion of phospholipids
- Conventional cleanup technologies lose up to 5% of the feedstock:
- phospholipids and gums are removed as wastes
- lipids are lost in spent bleaching clay
- lipids are lost in spent activated carbon
- Lipids are lost in wastewater emulsions
No equipment modifications required
for highly-contaminated feedstocks
- HCU uses the same process
regardless of inorganic content in the feedstock.
- Operating costs are similar for
RBD soybean oil (20ppm inorganics),
DCO (50 ppm inorganics),
UCO (200-500 ppm inorganics),
and brown grease (>1000 ppm inorganics).
- Conventional technologies require
frequent changes of filter media
for higher inorganic content feedstocks.
- HCU performance has been successfully demonstrated
on many challenging feedstocks
- Distiller’s Corn Oil
- Used Cooking Oil
- Brown Grease
- Fatty Acid Distillate
- Phosphatide Gums
- Algal Oils (up to 70% phospholipids)
The HCU process consists of the following continuous flow steps:
- The renewable feedstock and water are pumped separately at system pressure into a a static mixer.
- The feed/water mixture is then heated to about 450°F by a feed-effluent heat exchanger, heated by a furnace and/or refinery high-pressure steam.
- From the heat exchanger, the heated mixture flows through an insulated tubular reactor that maintains temperature, provides turbulent flow for a 2-minute residence time, and transfers the metals and other inorganics from the feedstock into the water.
- Upon exiting the reactor, the processed material flows through the feed-effluent heat exchanger and a trim cooler that cools the material to about 200°F, and the pressure is reduced to near ambient.
- Finally, the material flows into a gravity oil-water separator where the clean organic phase and the aqueous/inorganics phase readily separate in a few hours.
HCU has been proven to successfully pretreat a wide range of feedstocks including:
- distiller’s corn oil (DCO)
- beef tallow
- used cooking oil (UCO)
- brown grease
- phosphatide gums
- crude degummed soybean oil
- soap stock
- pongamia oil
- refined and crude carinata oil
- palm oil
- algal oil
HCU can be used as a degumming process as it hydrolyzes phospholipids. It can also be used as an acidulation process for converting soaps to clean free fatty acids.