Gasification and Conversion of Waste to Energy PAT-SRCDOW™ Systems
Figure 1: Oily Waste Sludge lagoon
According to the World Bank, the world currently generates about 4 billion tons of all types of waste per year. The world’s cities alone generate about 1.5 billion tons of solid waste per year. The typical waste is made up of 24% MSW, 21% industrial waste, 36% construction and demolition (C&D) waste, 11% commercial waste, and 5% arises from wastewater treatment. Only 3% of the total solid waste is used for energy production, and there is a considerable potential to use the remaining waste for energy recovery.
The potential for recovering energy from renewable sources and organic waste products has been recognized for many years. Rapid growth of chemical technology has led to generation of large amount of waste products and chemicals deemed hazardous to human and ecological system.
PAT’s proprietary and unique SRCDOW™ process this type of wastes, destroying the organics and produce clean green fuel gas that can be used in the process. Gasification can reduce the volume of the waste and render it innocuous by destroying pathogens and toxic chemicals.
PAT process utilized a hybrid fluid bed steam reformer (HFBSR)with proprietary catalyst that destroys organics waste producing clean green fuel gas, and landfill acceptable solid waste. Figure 1. depicts a simplified schematic of PAT’s novel SRCDOW™ treatment process.
The material is received in the staging area and is fed into the receiving hopper of the feed system and transferred into a pre-dryer. Depending on feed type and moisture content the pre-dryer may not be required.
The system consists of a fluid bed steam reformer heated indirectly. The reactor is fluidized with superheated steam. The waste material is introduced via double lock hopper for solid feed material or pumped into the fluid bed reactor. The waste feed reacts with steam at temperature between 1100 OF (600 oC) to 1500 OF (816oC) to produce clean green medium BTU gas. The hot gas exiting the reactor flow into hot internal cyclone where large particulates are removed and returned into the fluid bed reactor. The product gas exit into a wet scrubber to cool the gas and remove the steam. Further cleaning is achieved depending on the feed constitute using packed bed gas scrubbers. The clean gas is burned in the utility boiler to generate steam for the fluid bed reactor. Typical Green Gas Fuel Composition.
Typical Green Gas Fuel Composition
The heat required for the gasification is supplied indirectly by combustion heaters. The flue gas from the heaters is cooled in waste heat recovery steam generator. The flue gases from the combustion heater do not come into contact with contaminated material.
PAT’s technology provides an efficient indirectly heated gasification route to overcome the limitations of the alternative technologies. The indirect gasifier has significant advantages over conventional technologies. The unit produces clean green fuel gas which can be combusted in a gas-fired boiler.
PAT’s SRCDOWT™ can process a wide range of feed stock waste such as:
Petroleum oily sludge
Contaminated soil
Kraft mill sludge
Recycle fiber mill waste
RDF
MSW
Low level radioactive waste
Coke
Oil-shale
Municipal waste
Industrial waste
Agricultural and animal waste