ScrollTherm Process Overview

ScrollTherm Process Applications

CEtech has developed a robust hazardous and radioactive waste treatment process that provides enhanced processing capability for a very wide variety of waste materials. The ScrollTherm process is well suited for safe and cost-effective thermal treatment of many wastes, described below.

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The ScrollTherm process is readily scalable to a wide range of processing capacities:

• Compact, Transportable, Modular Systems

  • Batch thermal treatment of wastes, such as high-activity ion exchange resins, with throughput of 100 to 500 L (3.5 to 18 cubic feet) per day.  

  • Continuous system with daily waste treatment throughput of up to 1000 L (35 cubic ft.).

• Fixed-Base Central Processing Facility

  • Fixed (non-transportable) thermal treatment process systems for hazardous and radioactive waste treatment of up to 5.4 cubic meters (192 cubic feet) of high-activity ion exchange resins or 15 L/min (4.0 gpm) per day of water-based, nitrate-based or organic solutions or slurries per processing train.

ScrollTherm Process Capabilities

CEtech has developed a unique process for thermal treatment of a variety of solutions, slurries, pastes, wet cakes and solids including radioactive and hazardous wastes. The CEtech ScrollTherm process was developed as an integrated, turnkey processing system that can thermally treat a wide variety of materials using a cost-effective, versatile, robust, electrically heated process.

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ScrollTherm systems can efficiently thermally treat the following materials into a wide variety of products or thermally treated residues. Thermal treatment can be performed from near ambient temperatures to over 700°C (1300°F) under vacuum or positive pressures with outlet process gas flows near theoretical minimums. Typical operating temperatures for treatment of most materials are readily controlled between 350 and 650˚C (660 to 1200˚F) by use of electrical heat input (eliminates use of fossil and carbon-based fuels).

• Liquids, solutions, slurries, and pastes

  • Evaporate water or organic liquids to produce a more concentrated solution or slurry or dry, free-flowing crystalline or powder products without fouling, foaming, paste agglomeration and caking typical of most drying processes.

  • Evaporate water or organic liquids to produce a uniform melted product from the dried solids.

  • Evaporate water or organic liquids and thermally denitrate solutions and slurries with elevated nitric acid, hydroxide, nitrate and/or nitrite content to produce a dry, solid nitrate/nitrite-free product.  By adding one or more inorganic co-reactant(s) during treatment the dry solids can be converted into water-insoluble, stable, mineralized products in a single-step process.

• Solids

  • Evaporate water or evaporate and/or pyrolyze organic materials to produce a dry, volume reduced, organic-free solid product.

  • Mix and contact solids with co-reactants to produce a modified or new chemical compound as the product.

  • Mix and melt one of more solids to produce a uniform melted or slurried product.

ScrollTherm Process Specifications and Features

For radioactive and/or hazardous waste treatment, the ScrollTherm process has the following capabilities and features.

• High Treatment Capacity with Reduced Emissions   

ScrollTherm units are compact and electrically heated which greatly reduces the amount of process gas and offgas flows produced during waste treatment operations. Significantly smaller offgas support systems are required compared to many thermal treatment processes for equivalent throughput. For example, for treatment of radioactive ion exchange resins the process gas produced by a ScrollTherm unit is only 22% to 28% of the process gas flows from a fluidized bed steam reforming system (FBSR) for the same waste treatment throughput.

• Energy Efficient and Environmentally Friendly  

ScrollTherm process systems are electrically heated and do not use fossil or organic-based fuels, which minimizes resultant carbon dioxide released to the environment. In addition, overall energy requirements are greatly reduced. For example, for treatment of radioactive ion exchange resins the energy required by a ScrollTherm unit is only 20% to 25% of the energy required to operate a FBSR for the same waste treatment throughput.

• Readily shielded  

Compact modular ScrollTherm process systems are readily shielded with 15 to 25 cm (6 to 10 inches) of removable steel plate shielding to allow treatment of highly radioactive wastes, such as ion exchange resins from nuclear facilities with contact dose rates of up to 6 Gy/hr (600 Rad/hr) while maintaining personnel exposure ALARA. Additional shielding and remote maintenance features can be applied for treating very high activity wastes.

• Transportable Systems  

Compact modular systems for ScrollTherm batch intermediate treatment capacity process systems can be truck transported between reactor or treatment sites. ScrollTherm batch ion exchange resin treatment systems can thermally treat 100 to 500 L (3.5 to 18 cubic feet) per day of radioactive resins or other wastes to produce a stable, dry, organic-free final treated residue on a batch-basis. One heavily shielded module and one non-shielded module comprise a complete, transportable thermal treatment system.

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Transportable intermediate capacity continuous process systems can thermally treat up to 1000 L (35 cubic feet) per day of radioactive ion exchange resins or other wastes. One heavily shielded module and one non-shielded module comprises a complete, transportable thermal treatment system.

• Fixed-Base Central Processing Facility Capable  

Larger capacity ScrollTherm continuous treatment process systems can thermally treat up to 5.4 cubic meters (192 cubic feet) per day of radioactive ion exchange resins or 15 L/min (4.0 gpm) of water-based, nitrate-based or organic solutions or slurries per processing train.

• Solutions, Slurries, Pastes and Solids can be Treated   

The ScrollTherm process can safely and reliably thermally treat most radioactive and hazardous liquids, solutions, slurries, pastes, wet cakes and solids including the following radioactive and/or hazardous organic wastes: ion exchange resins, solvents (including chlorinated liquids), oils, decontamination solutions, plastics of all kinds, cellulose, cardboard, bitumen, sludges, etc.

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The ScrollTherm process can also safely and efficiently thermally treat and stabilize radioactive and/or hazardous waste streams including alkali metal compounds, tetraphenyl borate, nitrates, nitrites, nitric acid, hydroxides, phosphates, sulfates, chlorides, fluorides, compounds that melt, biomass, etc.  Nitrates, nitrites and nitric acid are destroyed with very low resultant NOx in process gas.

• Robust Code Compliant   

ScrollTherm process system designs and construction meet ASME, PED, ANSI, ISO and related codes and standards as required for each application.

 

Figure 1 shows typical ion exchange resins before and after ScrollTherm thermal treatment. Treated residues are significantly volume reduced and comprise the radioactive metals and inorganic contaminants (crud/dirt) on the incoming resins together with non-organic carbon residues from the thermal destruction of the polystyrene or polyacrylate resin polymer structure.

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Figure 2 shows the water-insoluble mineralized treated residues from ScrollTherm thermal treatment of simulated US Department of Energy (DOE) Hanford nuclear reservation Low-Activity Tank Waste (LAW), an alkali nitrate-based solution.

 

The mineralized, water insoluble, alumino-silicate product can be readily solidified to produce a highly leach-resistant final waste form for disposal with no nitrates or nitrites in the treated residues.

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Status of ScrollTherm Technology

The ScrollTherm technology is available for licensing to waste generators and waste treatment processors. CEtech welcomes the opportunity to provide technical information to interested companies including technology reports that provide technical information and performance data for several applications, pilot and lab test data and modular system designs.

 

Please contact CEtech to request the following documents for additional detailed process information:

 

• Technology Report, CEtech-TSD-01   provides process and system descriptions and case studies of the ScrollTherm process for treatment of a variety of waste streams. Includes test data and results from pilot-scale ScrollTherm treatment of several simulated waste streams.

 

Comparison with Alternative Processes

Unique features of the ScrollTherm process vessel (STV) compared with other commercially available thermal treatment processes are provided in Tables 1 and 2, provided below.

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ScrollTherm is a registered US trademark of CEtech LLC

US and International Patents Pending