Technology
Consideration has been given to several technologies including solar electric, solar thermal, local wind, imported wind, anaerobic digestion, traditional stoker combustion, fluidized bed combustion, pyrolysis, gasification, and plasma arc. Some of these technologies are limited in their ability to supply considerable quantities of thermal (steam) and electrical energy required to recycle paper.
At this time the most feasible options are anaerobic digestion, traditional combustion and gasification:
Anaerobic Digestion
AD is a biological process that decomposes wet biomass (ie organic materials) with microbes to produce biogas.
Click here for more information on Anaerobic Digestion
Traditional Combustion
Traditional Combustion uses the heat of combustion of biomass (see dry biomass and RDF pages) to produce electricity and steam.
Click here for more information on Traditional Combustion
Gasification
Gasification is is a process that would converts dry biomass, into carbon monoxide and hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen resulting in synthesis gas. This gas can be combusted in a boiler to produce steam or electricity.
Click here for more information on Gasification
Understanding Technology Options
RCAP Technology Presentations
Alternative Resources, Inc. Technology Presentation November, 2007
Wind & Solar Presentation December 10, 2007
Frequently Asked Questions
What is electrical energy? What is thermal energy?
Electrical Energy or Electricity is the movement of electrical charges through conductors or wiring. Rock-Tenn uses electrical energy to power equipment, motors and lighting throughout the recycling plant.
Thermal Energy or heat, is the internal energy produced from the vibration and movement of the atoms and molecules within substances. Rock-Tenn uses thermal energy in the form of steam.
What are the traditional project applications of each of these technologies?
Solar (Electrical) Current projects have been successful producing electricity for residential and small commercial facilities.
Wind power (Electrical) Current wind turbine installations generate electrical energy in locations with consistent, unobstructed access to strong winds.
Anaerobic digestion (Electrical & Thermal) is a process in which microorganisms break down biodegradable material while under oxygen deprivation. This process is widely used to treat waste water and organic wastes and produces methane gas that can be used to produce thermal energy or electricity.
Traditional Stoker (Electrical & Thermal) technology uses the heat of combustion of solid fuels to produce electricity and steam. Traditional stoker technology has been prolifically utilized worldwide for thermal and electric generation over the last century.
Fluidized bed (Electrical & Thermal) is a common technology in new steam and electric power plants that introduces solid fuel by feed ports into a compact vessel and suspends the fuel on upward-blowing jets of air during the combustion process resulting in a turbulent mixing of gas and solids. Fluidized bed technology has many applications but has recently been utilized widely in industrial applications because of its ability to use a variety of fuels and produce lower emissions.
Gasification (Electrical & Thermal) is a process that converts carbonaceous materials, such as coal, petroleum, or biomass, into carbon monoxide and hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen resulting in synthesis gas. This gas can be combusted in a boiler to produce steam or electricity.
What is cogeneration?
Cogeneration, also known as combined heat and power (CHP) is an energy plant that simultaneously generates both electricity and thermal energy. Conventional power plants generally emit the heat created as a byproduct of electricity generation into the environment through cooling towers, as flue gas, or by other means. CHP captures the byproduct (waste) heat for domestic or industrial heating purposes, located either very close to the plant, or distributed through pipes to remote facilities. Rock-Tenn currently uses cogeneration/CHP to generate all of it thermal energy needs and approximately 40 percent of its electrical energy needs.
Why is conservation important and what conservation measures are being taken?
The process of recycling 1000 tons per day of paper into paperboard requires the same amount of energy as is used to power 22,500 average family homes. The project team has identified reductions of energy use by as much as 25%. This will inherently make Rock-Tenn a more valuable and cost-effective recycler, protecting it from highly variable market fuel and commodity prices. The project team is coordinating an extensive review of energy efficiency opportunities at the plant with engineering teams from Metso, HDR, and HVAC Systems Inc. A pilot project addressing the technical challenges of capturing the process' waste heat is underway, and will provide valuable data for selecting appropriate efficiency upgrades.
Click here for more information on energy conservation.
What is a district energy system?
District heating (district energy) is a system for distributing thermal energy (steam or hot water) generated in a centralized location for residential, commercial and industrial heating requirements such as space heating and water heating. The thermal energy is typically generated by a boiler plant or a CHP plant burning fossil fuels but increasingly biomass is being used. District heating systems can be served by heat-only boiler stations or geothermal systems. Locations in Europe are also using central solar heating to generate thermal energy for district heating systems. District heating systems are used in many U.S. cities and college and university campuses. District heating and cooling systems are also widely used throughout Europe and Asia.