Patent-Pending Expertise Converts “Waste” Carbon Into Helpful Chemical compounds and Helpful Parts

Technology


Hydrothermal Liquefaction Process Animation

Waste carbon from farms, sewage and different sources could be processed into high-grade bio-based fuels extra simply with a brand new PNNL-developed movement cell. On this animation, the movement cell receives biocrude and wastewater from a hydrothermal liquefaction course of. It then removes carbon from wastewater, permitting the clear water to be reused. The system even generates hydrogen, a helpful gas that may be captured, decreasing the price of the entire operation. Credit score: Sara Levine | Pacific Northwest Nationwide Laboratory

Patent-pending course of removes biofuel contaminants from wastewater utilizing an additive-free course of that generates hydrogen to gas its personal operation

The holy grail of biofuel researchers is to create a self-sustaining course of that converts waste from sewage, meals crops, algae, and different renewable carbon sources into fuels whereas maintaining waste carbon out of the environment and water. Though a lot progress has been made in reworking such trash into usable gas, finishing the cycle with clear vitality has confirmed to be a tough nut to crack.

A group of researchers on the Division of Vitality’s Pacific Northwest Nationwide Laboratory (PNNL) has now devised a system that accomplishes simply that. The PNNL electrocatalytic oxidation gas restoration system converts what was beforehand regarded as unrecoverable, diluted “waste” carbon into helpful chemical substances whereas additionally producing helpful hydrogen. As a result of renewable vitality is used, the method is carbon-neutral and even probably carbon-negative.

The important thing to creating all of it work is an elegantly designed catalyst that mixes billions of infinitesimally small metallic particles and an electrical present to hurry up the vitality conversion at room temperature and stress.

Juan A. Lopez Ruiz PNNL

Juan A. Lopez-Ruiz, a PNNL chemical engineer, led a analysis group that not too long ago developed a novel movement cell reactor that makes the trail to renewable gas simpler. Credit score: Andrea Starr | Pacific Northwest Nationwide Laboratory

“The presently used strategies of treating biocrude requires high-pressure hydrogen, which is often generated from pure gasoline,” stated Juan A. Lopez-Ruiz, a PNNL chemical engineer and venture lead. “Our system can generate that hydrogen itself whereas concurrently treating the wastewater at close to atmospheric situations utilizing extra renewable electrical energy, making it cheap to function and doubtlessly carbon impartial.”

A hungry system

The analysis group examined the system within the laboratory utilizing a pattern of wastewater from an industrial-scale biomass conversion course of for over 200 hours of steady operation with out shedding any effectivity within the course of. The only constraint was that the analysis group’s wastewater pattern had run out.

“It’s a hungry system,” Lopez-Ruiz stated. “The response charge of the method is proportional to how a lot waste carbon you are attempting to transform. It may run indefinitely in the event you had wastewater to maintain biking by it.”

The patent-pending system solves a number of issues which have plagued efforts to make biomass an economically viable supply of renewable vitality, in keeping with Lopez-Ruiz.

“We all know the best way to flip biomass into gas,” Lopez-Ruiz stated. “However we nonetheless battle to make the method energy-efficient, economical, and environmentally sustainable—particularly for small, distributed scales. This technique runs on electrical energy, which might come from renewable sources. And it generates its personal warmth and gas to maintain it operating. It has the potential to finish the vitality restoration cycle.”

“As the electrical grid begins to shift its vitality sources towards integrating extra renewables,” he added, “it makes an increasing number of sense to depend on electrical energy for our vitality wants. We developed a course of that makes use of electrical energy to energy conversion of carbon compounds in wastewater into helpful merchandise whereas eradicating impurities like nitrogen and sulfur compounds.”

Closing the vitality hole

Hydrothermal liquefaction (HTL) is a really environment friendly technique for changing moist waste carbon to gas. This course of, in essence, shortens the time required to supply pure fossil fuels by turning moist biomass into energy-dense biocrude oil in hours somewhat than millennia. Nevertheless, the method is incomplete within the sense that the wastewater generated as a part of the method requires additional therapy to be able to get added worth from what would in any other case be a legal responsibility.

“We realized that very same (electro)chemical response that eliminated the natural molecules from wastewater might be additionally used to straight improve the biocrude at room temperature and atmospheric stress as effectively,” Lopez-Ruiz stated.

That is the place the brand new PNNL course of comes into play. Unrefined biocrude and wastewater could be fed into the system straight from an HTL output stream or different moist waste. The PNNL course of consists of what’s known as a movement cell the place the wastewater and biocrude flows by the cell and encounters a charged surroundings created by an electrical present. The cell itself is split in half by a membrane.

Flow Cell Bioreactor PNNL

A brand new patent-pending movement cell bioreactor developed at Pacific Northwest Nationwide Laboratory can purify wastewater (seen right here) and generate hydrogen to assist gas the method. Credit score: Andrea Starr | Pacific Northwest Nationwide Laboratory

The positively charged half, known as an anode, incorporates a skinny titanium foil coated with nanoparticles of ruthenium oxide. Right here, the waste stream undergoes a catalytic conversion, with biocrude being transformed to helpful oils and paraffin. Concurrently, water-soluble contaminants, reminiscent of oxygen and nitrogen-containing compounds, endure a chemical conversion that turns them into nitrogen and oxygen gasses—regular elements of the environment. The wastewater that emerges from the system, with contaminants eliminated, can then be fed again into the HTL course of.

On the negatively charged half of the movement cell, known as a cathode, a unique response takes place that may both hydrogenate natural molecules (reminiscent of those in handled biocrude) or generate hydrogen gasoline—an rising vitality supply that the movement cell builders see as a possible supply of gas.

“We see the hydrogen byproduct generated by the method as a internet plus. When collected and fed into the system as a gas, it may hold the system operating with fewer vitality inputs, doubtlessly making it extra economical and carbon-neutral than present biomass conversion operations,” stated Lopez-Ruiz.

The velocity of chemical conversion supplies an additional advantage to the system.

“We did a comparability of charges—that’s how briskly we will take away oxygen from natural molecules with our system versus the energy-intensive thermal elimination,” Lopez-Ruiz stated. “We obtained greater than 100 instances greater conversion charges with the electrochemical system at atmospheric situations than with the thermal system at intermediate hydrogen pressures and temperatures.” These findings had been revealed within the Journal of Utilized Catalysis B: Environmental in November 2020.

Lowering uncommon Earth metallic use

One vital drawback of many industrial applied sciences is their dependency on uncommon Earth metals, typically known as platinum group metals. The worldwide provide chain for these components is principally reliant on outdated extraction applied sciences which are energy-intensive, use monumental quantities of water, and generate hazardous waste. In keeping with the Division of Vitality, which has made home provide a major precedence, imports account for one hundred pc of america’ provide for 14 of 35 vital supplies and greater than half of 17 others.

The system addresses this downside by incorporating a novel technique of depositing nanoparticles of the metals chargeable for the chemical conversion. These particles have a big floor space, which requires much less metallic to do its work. “We discovered that utilizing metallic nanoparticles versus metallic skinny movies and foils lowered the metallic content material and improved the electrochemical efficiency,” stated Lopez-Ruiz. These findings had been not too long ago revealed within the Journal of Utilized Catalysis B: Environmental. The novel catalyst requires 1,000 instances much less valuable metallic, on this case ruthenium, than is often wanted for comparable processes. Particularly, the laboratory-scale movement reactor makes use of an electrode with about 5 to fifteen milligrams of ruthenium, in contrast with about 10 grams of platinum for a comparable reactor.

About these ineffective carbon compounds

The analysis group has additionally proven that the PNNL course of can deal with the processing of small water-soluble carbon compounds—byproducts discovered within the water waste stream of present HTL processes—in addition to many different industrial processes. There are a few dozen of those devilishly tough to course of small, carbon compounds within the wastewater streams at low concentrations. Till now, there was no cost-effective know-how to deal with them. These short-chain carbon compounds, like propanoic acid and butanoic acid, undergo transformation to fuels, such as ethane, propane, hexane, and hydrogen, during the newly developed process.

A preliminary cost analysis showed the electricity cost required to run the system can be fully offset by running the operation at low voltage, using the propane or butane to generate heat and selling the excess hydrogen generated. These findings were published in the July 2020 issue of the Journal of Applied Electrochemistry.

Battelle, which manages and operates PNNL for the federal government, has applied for a United States patent for the electrochemical process. CogniTek Management Systems (CogniTek), a global company that brings energy products and technology solutions to market, has licensed the technology from PNNL. CogniTek will be integrating the PNNL wastewater treatment technology into patented biomass processing systems that CogniTek and its strategic partners are developing and commercializing. Their goal is the production of biofuels, such as biodiesel and bio jet fuels. In addition to the commercialization agreement, PNNL and CogniTek will collaborate to scale up the wastewater treatment reactor from laboratory scale to demonstration scale.

“We at CogniTek are excited by the opportunity to extend the PNNL technology, in combination with our core patents and patent pending decarbonization technology,” said CogniTek Chief Executive Officer Michael Gurin.

The technology, dubbed Clean Sustainable Electrochemical Treatment—or CleanSET, is available for license by other companies or municipalities interested in developing it for industry-specific uses in municipal wastewater treatment plants, dairy farms, breweries, chemical manufacturers and food and beverage producers. To learn more about how this technology works, or to schedule a meeting with a technology commercialization manager, visit PNNL’s Available Technologies site.

In addition to Lopez-Ruiz, the PNNL research team included Yang Qiu, Evan Andrews, Oliver Gutiérrez and Jamie Holladay. The research was supported by the Department of Energy’s Advanced Manufacturing Office and the Chemical Transformation Initiative, a Laboratory Directed Research and Development Program at PNNL. Portions of the research were conducted as part of a Cooperative Research and Development Agreement with Southern California Gas Company.

References: “Anodic electrocatalytic conversion of carboxylic acids on thin films of RuO2, IrO2, and Pt” by Yang Qiu, Juan A. Lopez-Ruiz, Udishnu Sanyal, Evan Andrews, Oliver Y. Gutiérrez and Jamie D. Holladay, 25 June 2020, Applied Catalysis B: Environmental.
DOI: 10.1016/j.apcatb.2020.119277

“Electrocatalytic valorization into H2 and hydrocarbons of an aqueous stream derived from hydrothermal liquefaction” by Juan A. Lopez-Ruiz, Yang Qiu, Evan Andrews, Oliver Y. Gutiérrez and Jamie D. Holladay, 9 July 2020, Journal of Applied Electrochemistry.
DOI: 10.1007/s10800-020-01452-x

“Electrocatalytic decarboxylation of carboxylic acids over RuO2 and Pt nanoparticles” by Yang Qiu, Juan A. Lopez-Ruiza, Guomin Zhu, Mark H. Engelhard, Oliver Y. Gutiérrez and Jamie D. Holladay, 1 January 2022, Applied Catalysis B: Environmental.
DOI: 10.1016/j.apcatb.2021.121060

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