Technology

The ZERE solution uses biomass waste such as wood, paper and grass clippings, or biorefinery waste as fuel for our patent pending process, which then feeds into an off the shelf power generation cycle to produce on-site combined heat and power. The system has inherent CO₂ liquefaction and capture that provides a cheap, price stable, zero emission energy supply. The use of biomass combined with zero emissions leads to easy permitting and low site impact.

ZERE’s Air Independent Internal Oxidation (AIIO) is a technology solution for generating zero emissions electric power and process heat (CHP).  Fuel is oxidized internally using a solid stage oxygen carrier (metal oxide), capturing nearly 100% of the fuel energy and forming no pollutants.  Carbon dioxide (CO₂) captured from the oxidation is liquefied for sequestration or sale.  The spent oxygen carrier is regenerated by reacting it with the oxygen in air, again forming no pollutants.  The fuel energy is converted to electric power and heat by steam and/or gas turbine power cycles.  The initial target plant size is between 1 and 10 MW.

AIIO technology captures the higher heating value of the fuel which gives the process a higher efficiency than traditional systems that only capture the lower heating value.  In addition, the gaseous outputs from the fuel reactor are simply steam and CO₂.  These two benefits of AIIO combined allow for the CO₂ to be separated and captured while still maintaining a plant efficiency at or above those of traditional gas turbine systems.

ZERE’s patent protected, AIIO technology provides high efficiency zero GHG emissions combined heat and power with integrated CO₂ capture.  It stands apart from other sources of generation in the following ways:

• Most small scale CHP equipment in use today, even with biomass fuel, emit CO₂ and other GHGs.
• Adding post combustion pollution control and CO₂ capture equipment to traditional power plants decreases the plant efficiency by up to 7% and increases the cost of electricity production by 12%.
• Oxy-fuel combustion using refrigeration air separation has high capital cost, high parasitic electric power requirements and is not practical for smaller sites.  Oxy-fuel combustion using pressure swing absorption air separation has high parasitic electric power losses.  Both oxy fuel technologies have lower total plant efficiency.

Benefits of Chemical Looping

ZERE’s AIIO technology is a form of chemical looping. Chemical Looping is a promising technology for fuel combustion preventing CO₂ dilution with other gases, mainly nitrogen. In CLC, a solid oxygen carrier supplies the oxygen needed for CO₂ and water formation. Since the oxygen is provided without air, this provides a nitrogen free mixture. As a result, the requirement of CO₂ separation from flue gases, a major cost for CO₂ capture, is circumvented. A good oxygen carrier for CLC reacts easily with fuel and can be reoxidized in air. A typical oxygen carrier is formed with a metal oxide and an inert binder, which together provide, oxygen storage, fluidizability and mechanical strength. Over the last 10 years, several research groups have been researching oxygen carriers which are both active and stable under fluidized bed conditions.

Technical Papers

The California Energy Commission (CEC) Independent Assessment Report gives a favorable review of the work done by ZERE (formerly Clean EnGen Group, LLC) and Stanford a 2008 CEC EISG grant.

The California Energy Commission Final Report describes the work done by ZERE (formerly Clean EnGen Group, LLC) and Stanford under the 2008 CEC EISG grant.

A DNS of a CuO particle in CO Environments by E. A. Goldstein and R.E. Mitchell, Stanford University, 2011

Chemical Kinetics of Copper Oxide Reduction with Carbon Monoxide by E. A. Goldstein and R.E. Mitchell, Stanford University, 2010

Applications of Chemical Looping Combustion of Solid Fuels by E. A. Goldstein and R. E. Mitchell, Stanford University, 2009

Copper Oxide as an Oxygen Carrier for Chemical Looping Combustion by E. A. Goldstein and R. E. Mitchell, Stanford University, 2009