Liberty Energy Center Process Description

Environmentally sustainable, close-coupled thermal gasification of
biofuels for the gernation of renewable electricity.

The Liberty Energy Center will use the latest Diagram of BioSolids ProcessAn inline depiction of the process. Diagram of BioSolids Porcess, Click to see a larger version generation of bubbling fluidized bed gasification technology to produce a fuel gas which is then oxidized in a furnace to produce high pressure steam. The steam will drive a condensing steam turbine coupled with a synchronous generator to continuously produce electricity which is fed into the local distribution system and made available for local needs. The steam will be condensed and re-used. Cooling water needs will be minimized through innovative recovery of water from the gasification process.

All handling of biosolids, including truck reception and conveying, will occur indoors or in controlled air environments to prevent release of odors.

Environmental Safeguards
Liberty Energy Resources is committed to operating the facility in a safe and environmentally sensitive manner. The Liberty Energy Center will be located near Lost Hills, across Holloway Road from the existing Liberty Compost operation. The Liberty Energy Center will use the most advanced technologies to ensure that air, water and noise emissions are well below regulatory limits, and below any even lower thresholds that might cause impact on wildlife or neighbors. Liberty is working, and will continue to work, with local, County, State and Federal agencies to develop and implement mitigation and management plans to ensure that all environmental commitments are kept. The environmental performance of the facility will be monitored on a continuous basis in compliance with the facility’s Conditional Use Permit and San Joaquin Valley Air Pollution Control District permit.

Greenhouse Gases
The Liberty Energy Center will actually have a beneficial effect on the carbon cycle for a number of reasons: The biosolids and biomass fuels used are both “carbon-neutral’ - the carbon released by gasification is taken up again by the next cycle of biomass and biosolids. The flyash produced will be used as a substitute for Portland cement, avoiding the generation of greenhouse gases in its production. Finally, the renewable electricity produced will displace ‘brown’ electricity generated from the combustion of coal and natural gas.

Air Quality Maintained
The emissions control systems in the Liberty facility will set a new standard for robust environmental stewardship:

  • The high temperature, time and turbulence in the bubbling fluidized sand bed will ensure highly efficient gasification and combustion, while minimizing the formation of pollutants.

  • Both selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) systems will be used for control of NOX.

  • Flue gases will pass through a fabric filter system, or ‘baghouse’ to capture small particulate matter, acting like the filter in a high efficiency vacuum cleaner.

  • Sulfur dioxide (SO2) emissions will be controlled through addition of limestone to the fluid bed, and through a spray-type scrubber downstream of the boiler, in which a quick lime solution is sprayed to react with the SO2.

  • Trace amounts of mercury may be present in biosolids. This mercury enters the municipal wastewater system from dental offices and other sources. Powdered carbon will be sprayed into the flue gas stream to absorb any remaining mercury. The particles will then be removed from the gas in the baghouse and disposed.

 

Odors Minimizedimage of plant stacks
To control and eliminate odors, biosolids will be transported to the site in enclosed trailers and stored in sealed silos. Vapors from the silos will be captured and destroyed in the gasifier. Green biomass will be used as it is delivered and not stored at length on site.

Water Protected
Liberty will use leading-edge systems to recover water vapor from the flue gases, in order to re-use them and greatly reduce requirements for water. Clean process water from the plant will be used for nearby agricultural operations.

Noise Controlled
Measures will be taken throughout the plant design process, selection and placement of equipment, and grading and landscaping to minimize noise levels in the areas surrounding the facility.