Plasma Resource Recovery Technology: Converting Waste to Energy and Valuable Products

Plasma Resource Recovery (PRR) is a revolutionary technology that can treat virtually any type of waste by combining gasification with vitrification. Vitrification produces inert slag that can be used as a construction material. Gasification produces a fuel gas containing carbon monoxide (CO) and hydrogen (H2), used for cogeneration of electricity and steam. The plasma fired eductor which is the core technology of the PRR system is presently being used commercially on a cruise ship at a scale of 5 TPD. The capabilities of the PRR technology have been demonstrated in a pilot plant, at a rate of up to 2 TPD of various types of waste. Because of the high intensity of the plasma flame and the reduced amounts of gases produced in a gasification system, compared to traditional combustion systems, the PRR system is typically very compact. As such, the PRR technology opens the door for a decentralized, small scale approach to waste management.

Ash Management and Metals Recovery in Broward County, FL

Broward County (the County), which is located on the southeast coast of Florida, is currently faced with an ash management and metals recovery decision. The County has two mass burn resource recovery plants and they process a combined total of approximately 1.65 million tons of MSW. The ash residue from these two facilities is currently landfilled. At one facility, the South Broward Waste-to-Energy Facility (the South County Facility), ferrous was being recovered at the ash monofill using mobile equipment, as the plant was not equipped with metals recovery equipment. But as market prices dropped, so did the ferrous metals recovery. This has adversely affected the useful life of the ash monofill, owned by the County. The County is looking for a cost–effective alternative for an on–line metals (ferrous and non–ferrous) recovery system.

Improving Semi-Dry Scrubber Performance Through Gas Flow Modeling

Poor flue gas flow distribution in the semi-dry scrubbers used in Waste-to-Energy facilities can cause reduced residence time for lime slurry spray droplet evaporation and subsequent “wet carryover” resulting in solids deposits on the scrubber vessel walls and ductwork and also baghouse bag blinding. In addition to promoting corrosion, the removal of deposits during boiler outages is very labor intensive. This paper identifies how gas flow modeling conducted in conjunction with Nels Consulting Services, Inc. on several different types of scrubbers at Covanta Energy’s Waste-to-Energy facilities resulted in modifications which increased the actual flue gas residence time, considerably reduced the solids deposits (scale) and associated maintenance costs, and in some cases reduced the pressure drop across the scrubbers and baghouses. The data presented includes typical model study velocity distribution data (before and after the modifications), vessel sketches, and photographs. Associated work included in-field scrubber outlet duct temperature and velocity distribution testing. The results of the in-field scrubber outlet temperature distribution testing, done both before and after the scrubber modifications, confirmed the improvements numerically by showing reduced flue gas temperature variation in the scrubber outlet duct.

The Use of Data Quality Objective Procedures: To Control Complex Inter-Related Environmental Problems for Metal Matrix Encapsulation Fly Ash Management

The Data Quality Objective Procedure (DQOP) method aids implementing environmental polices, as engineering solutions. Pollution control issues identified and addressed through new environmental legislation need to be implemented. The metal matrix encapsulation (MME) treatment works as a toxicity reduction exercise that can legally control disposal of fly ashes from waste-to-energy plants. The MME process aids with the implementation of European Union (EU) legislation such as the Waste Incineration Directive by allowing fly ashes to be disposed of in landfill sites. By using the DQOP, as shown with the MME fly ash treatment, complex issues can be clearly identified and effectively controlled. The method considers various steps into which different activities can be addressed, agreed upon and allows engineering, financial and legal teams to cooperate. The EU is the world’s second largest economy with many waste management requirements. The DQOP can aid entry into this complex but rich economic opportunity.

York Resource Recovery Center Control System Upgrade

The York Resource Recovery Center was constructed and completed for the York County Solid Waste and Refuse Authority by Westinghouse Electric Corporation in October 1989. The design incorporated three Westinghouse O’Connor Rotary Combustors fitted with Deltak Boilers to provide a state-of-the art incineration system for the 400,000 residents of York County. Westinghouse incorporated many of their industrial products into the plant including their Westinghouse Data Processing Family Control System (WDPF) for control of the plant combustion and generation process.

Reprocurement Considerations for an Existing Municipally Owned Refuse-to-Energy Plant: Pinellas County, Florida

On May 7, 2007, the operating agreement for the Pinellas County mass-burn resource recovery facility will expire. This contract, originally negotiated in the late 1970’s is one of the first in the United States for the design, construction, operation and maintenance of a municipally owned refuse-to-energy facility, and thus is one of the first to expire. In late 2003, Pinellas County began the process to reprocure an operator for its resource recovery facility under the terms of a new long-term agreement. This paper discusses planning processes and reprocurement activities to date, including hiring a reprocurement consulting engineer; formation of the project team (Project Working Group and Project Oversight Committee); development of the project schedule; and, identification of the reprocurement approach (informal meetings with vendors, Request for Qualifications and Request for Proposals). The paper also addresses certain technical and contractual issues associated with contracting a 24-year old refuse-to-energy facility. Technical items considered are a modified approach to ash processing and metals recovery; whether or not to continue the WESPhix® ash treatment process; and the need for various capital improvements. Contractual matters include such items as ownership of spare parts; availability of operating documents and record drawings; transfer of proprietary licenses; and consideration of a transition agreement. Pinellas County’s reprocurement is being designed with the primary goal of developing a process that is fair, open and competitive; and one that provides a level playing field for all interested proposers. The paper draws comparisons between the reprocurement methods and processes considered, with conclusions about why the final reprocurement approach was selected.

Thermo-Gravimetric Analysis (TGA) of Combustion and Gasification of Styrene-Butadiene Copolymer (SBR)

An investigation has been initiated to determine the effects of various atmospheres (6.9% O2/N2, 21% O2/N2 (air), 30% O2/N2, 3% H2/N2 and pure N2) on the efficiency of gasifying or combusting rubber waste to produce synthesis gas or generate steam or power. This paper reports on the findings from a series of TGA experiments at various heating rates on styrene-butadiene copolymer (SBR), which is the main starting component for tire manufacturing. The results indicate that oxygen enhanced atmospheres have a significant effect on increasing combustion efficiency at the tested heating rates. A hydrogen-spiked atmosphere, surprisingly, did not have a significant effect on the gasification rates of SBR at any heating rate; in addition, this atmosphere resulted in a carbon residual that remained in the sample carrier, something that was not observed in the other atmospheres, including pure nitrogen. An unexpected result of the N2-O2 tests was the development of a plateau in the mass-loss versus temperature curves, at temperatures near 500°C.

Evaluating Waste Incineration as Treatment and Energy Recovery Method From an Environmental Point of View

During the last two decades, several research groups as well as consultants have been analysing the environmental impacts of incineration in comparison to other waste treatment options. Methods and models for describing these systems have been developed. Systems studies on local, regional and national level have been performed using a wide range of different modelling approaches. The aim of this paper is to describe the environmental performance of incineration with energy recovery in Europe in comparison with other options for waste treatment/recovery. This includes identifying key factors that largely affect the outcome from environmental systems studies where such comparisons are made. The paper focuses on mixed solid waste and on waste fractions where there has been a lot of controversy whether the material should be recycled, incinerated or treated biologically (e.g. paper, plastics, compostable material). The paper is based on a meta-study, where the above research field is mapped out in order to gather relevant systems studies made on local, regional and national levels in Europe. By thoroughly examining these studies, conclusions are drawn regarding the environmental performance of incineration with energy recovery and regarding key factors affecting the environmental results.

Validation Study of FTIR-Based Emissions Measurements at a Municipal Waste Combustor

EPA Test Methods 301 and 320 include statistical techniques for validating sampling methods in specific gas matrices. Several of these techniques were used to analyze extractive FTIR data collected at a municipal solid waste incinerator and to validate the method for hydrogen chloride (HCl) measurements. FTIR results for carbon monoxide (CO), sulfur dioxide (SO2), and nitric oxide (NO) were also compared to measurements recorded by the facility’s continuous emissions monitors (CEMs). Presented are discussions of the equipment, spectral analyses, and statistical comparisons of the various test methods.

Waste to Energy in the 21st Century: Getting New Projects/Expansions off the Ground — Key Ingredients to a Successful Action Plan (Abstract)

These are critical times for users and vendors of waste-to energy technologies in the US. Many of the existing long term contracts entered into during the early to mid 80’s are nearing their end. Communities are facing the need to decide what to do with that portion of their waste stream remaining after they reduce, reuse and recycle. That effort includes determining the role that waste-to-energy will play in their 21st Century integrated solid waste management program and the nature of the contractual relationships that will define how it is managed.