6. technology presentations 6.3 alternative plasma ... · 2 table 2 freon destruction with the 15...

6. Technology Presentations

6.3 Alternative Plasma GeneratingTechnologies

Dr. Igor Polovtsev, United States

Plasmatron System for Toxic Gas and Liquid Destruction

Dr. Igor PolovtsevScientific Utilization Inc. USA

SUI began researching the possibility of using plasma for the destruction ofchemical warfare agents in 1994. By 1995, a test bench was assembled in orderto run simple preliminary tests of the technology.

This system consisted of a 1MW capacity AC Plasmatron PT- 1000 coupled witha four foot long water-cooled reactor. The material feed system was capable ofdelivering pulverized solids, liquids and gases into the plasma plume. The materialfeed rate was monitored with flow meters and/or by weight loss. Flue gases,before they were released into the atmosphere, were treated in a wet scrubber.Gas sampling was performed through sampling ports before and after thescrubber. Gas analyses were performed with the help of mass selectivechromatography.

The first substance tested was Malathion, an off-the-shelf compound which is veryclose in chemical structure to nerve gases. Results of the tests can be found inthe table below:

Table 1. Malathion Destruction with 500kW AC Plasmatron

Runs Malathion Flowkg/hr

Torch power, kW Malathionconcentration in offgases. Detectionsensitivity 0.0001

1 60 250 N/D2 120 360 N/D3 200 500 N/D

A smaller AC Plasmatron unit was used to do preliminary drug and freondestruction tests.

SUI continued its research of plasma technology destruction capabilities through aseries of International Science and Technology Center (ISTC) projects. The firstof those projects, devoted to chemical warfare agents, is already completed.

The scope of this ISTC research was to determine the destruction capabilities ofthe AC Plasmatron, and to determine the minimum power requirements forcomplete destruction. The test system assembled as a result of this project ispictured in Fig 1. Results of those tests are presented in table 2. Freon waschosen for this test because it is a relatively safe compound containing the moststable fluoride and chloride bonds.

2

Table 2 Freon Destruction with the 15 kW AC Plasmatron.

Run Freon flow kg/hr Torch Power kW FreonConcentration inoff gases.Detectionsensitivity .0001

1 5 15 N/D2 10 15 N/D3 14 15 N/D4 17 15 0.0002

Figure 1. 15 W AC Plasmatron Freon destruction System.

After conducting those tests, SUI started exploring the market for Freon andHalon destruction. It was discovered that there is a substantial demand not onlyfor large scale systems (100 kg to 1 ton per hour), but also for small, mobile,simple and reliable units capable of destroying small quantities of gases andliquids.

This discovery triggered the creation of SUI’s 1kW microwave plasma halogendestruction system. Figure 2 shows preliminary tests of the 1kW microwaveplasma torch with freon being injected into the plume. Experimental results arepresented in Table 3.

These tests proved that each kilogram of freon flow per hour requires 1kW of electricpower. They also proved that AC Plasmatrons can be used for destruction of

3

Table 3 Freon destruction tests with 1 kW microwave plasma torch

Run Freon flow kg/hr Torch PowerkW

Freon concentrationin the off gases

1 0.5 1 Less than 0.0001 %2 0.7 1 Less than 0.0001 %3 1 1 Less than 0.0001 %4 1.2 1 0.0025%5 1.5 1 0.3%

Figure 2. Shows preliminary tests of 1kW microwave plasma torch.

Current SUI joint projects with Lawrence Livermore National Laboratory and theInstitute of Problems of Electrophysics of the Russian Academy of Sciences, willdemonstrate the AC Plasmatron capabilities in the destruction of medical wasteand certain industrial hazardous wastes. SUI is the commercial partner in thisproject which is funded and managed jointly by the U.S. Department of Energyand the United States Industrial Coalition (USIC). Preliminary tests are completed.The full-scale system has been designed, and orders for the major long-lead-timeitems are already placed. An AC Plasmatron medical waste destruction system,

4

capable of destroying 300 – 350 pounds per hour of product, without grinding orshredding, will begin delivery and installation at SUI’s Huntsville Alabama facility inthe second quarter of 2001.

This system will ultimately consist of three AC plasma torches, a rotary kilnreactor, afterburner, dry quencher, heat recuperator, scrubber with venturiquencher, and utilities. It will be capable of meeting the tightest environmentalstandards.

Scientific Utilization, Inc.

Scientific Utilization, Inc.

Alternative Plasma GeneratingTechnologies for Cost Effective

CFC and Halon Destruction.

Alternative Plasma GeneratingTechnologies for Cost Effective

CFC and Halon Destruction.Keith Bucher, Igor Polovtsev.

Scientific Utilization, Inc.201 Electronics Blvd.

Huntsville, AL 35824

Keith Bucher, Igor Polovtsev.Scientific Utilization, Inc.

201 Electronics Blvd.

Huntsville, AL 35824

Scientific Utilization,Inc. Scientific Utilization,Inc.

Destruction of Ozone Depleting Substances

� Process specification and description.� Process Chemistry.� Exhaust Products.� Scrubber chemistry.� Process Diagram.� USCS Contraband and Freon Destruction System.� PT-7 based Freon Destruction System.� Microwave torch based Freon Destruction System.� Operation costs.� Conclusions.

Outline



System specifications.� Must be capable of safely destroying Freon and other

CFC and Halons..� Fed in a gas form.� Must meet EPA air pollution requirements.� Integrated system must have a small footprint.� Must have low energy consumption requirements.� Transportable or fully mobile configuration desirable.



Key Process Points

� Advanced Thermal Oxidation;� Plasma torch versatility allows system to maintain

high temperatures for a wide range of fuel oxidizerratios;

� Choice of oxygen as the primary oxidant eliminatesthe possibility of NOx formation;

� Rapid Quenching with neutralizing agent keepsdioxins and furans near zero.



Basic Chemistry

� Freon decomposition:

CCL2F2+O2 = CO2 + CL2 + F2

� Halon decomposition:

2CF2ClBr + 2O2 = 2CO2 + 2F2 + Cl2 + Br2

� CL2, F2, Br2 in a presence of water immediately formacids: HCL, HF, HBr.



Exhaust Gas Scrubbing� No Dioxins/Furans:

– Process temperature is carefully controlled just above1200 C

– Rapid quenching of exhaust gases will eliminatepossibility of Dioxin/Furan formation.

� No danger of NOx formation: there is no nitrogen inthe system.



Scrubber chemistry

� HCL, HF, HBr are neutralized in the scrubber bysodium hydroxide, lime or other neutralizers

� NaCl, NaF, NaBr, CaCl, CaBr salts a very soluablein water.

� Soluble salts are environmentally safe and can bedischarged into the sewer.

� CaF is insoluble in water and a special filtering anddisposal system is added.



Process Diagram

Plasmatorch Reactor

Temperatureabove 12000 C

Scrubberquencher

combination;80o C

Exhaust gases:Steam and CO2

Salt water with NaCl,NaF and NaBr

Approximately 80oC

O2

Freon

O2 stripper

Air

CO2Stripper



USCS ContrabandDestruction System� Meets California Air emissions

requirements� Destroy 120 lb of freon and 300

lb of contraband per hour� 99.9% solids conversion� Pyrolysis - Redox� Fully automated with Fail Safe

Cut Outs� Torch Power 250 kW

AC Plasma Technology



PT-7 AC PlasmatronFreon DestructionDemonstration System

� Torch power: 15 kW� System tests up to 17 kg/hr� Also capable of toxic gas and

military hazardous gasdestruction

� On going research with ISTC

AC Plasma Technology



1 kW Microwave PlasmaTorch Demonstration forFreon Destruction.� Good for small flows.� Complete destruction due to

efficient volume discharge.� Extremely cheap plasma torch

and systemics.� Very low operating costs.

Microwave Technology



Gas Treatment System USCS� Complete Gas Emissions

Monitoring and ControlsFeedback.

� Venturi Quencher.� Packed bed scrubber.� Metered /Computer

Controlled NeutralizerInjection.



– Gases monitored:• HF, HCl, HBr• Oxygen• Carbon monoxide.

– pH control in the scrubber.– Indicators on the PLC screen for operator.– Build-in Test and Diagnostics.

Gas monitoring and Control



Operating Costs, USCSElectrical costs on a daily basis� Plasma Torch – $ /lb;� Material Processing System – $ /lb;� Scrubber - $ /lb;� Utilities - $ /lb;� Control system - $ /lb;� Total - $ /lb.



Freon destruction experiment with 1 kW MWplasma torch

0.3 %11.55

0.0025 %11.24

Less then 0.0001 %113

Less then 0.0001 %10.72

Less then 0.0001 %10.51

Freon concentration in theoff gases

Torchpower, kW

Freon Flow,Kg/hr

Runnumber



Malathion destruction with 500 kW ACPlasmatron

N/D5002003

N/D3601202

N/D250601

Malathion concentrationin off gases

Detection sensitivity00.0001 %

Torch power,kW

Malathionflow, kg/hr

Run



Freon destruction with 15 kW AC Plasmatron

0.000215174

N/D15143

N/D15102

N/D1551

Freon concentration in offgases

Detection sensitivity00.0001 %

Torch power,kW

Freon flow,kg/hr

Run



Existing Plasma Generating Systems

Variety of workinggases.

Variety of working gases.Variety of working gases.

Reasonable powerconversion efficiency.

Can be scaled up to 1 MW.Simple Power Supply andConstruction.

Can be scaled up to 5MW.

Efficient operation for torchpressures up to atmospheric.

Acceptable electrode life forlow medium throughput.

No Electrodesrequired, lowmaintenance.

No Electrodes required, lowmaintenance.

Very efficient powerconversion to plasma.

LF RF TorchMicrowave TorchAC Plasmatron



Product Feed into USCDS



Material processing system



System in operation



Preparing product



Green House Gases Reduction

� Specially designed high efficiency gas membraneseparation systems have been developed forhazardous gas and electrical power co-generation.

� Projects:– Cost effective O2 stripping from atmosphere;– CO2 separation from water vapor and nitrogen in hot

exhaust gases of Cogen boilers and heat transfersystems.

Gas Membrane separation Development


6.4 Reactor Cracking

Dr. Siegismut Hug, Germany

[email protected] July 2000 1

Experiences with aCFC Decomposition Plant of

SOLVAY FLUOR UND DERIVATE GMBHat Frankfurt Germany

R.S. HugSolvay Fluor und Derivate GmbH

Hannover / Germany

We know today that problems such as ozone depletion, ozone hole, climate andgreenhouse effect are linked with chlorofluorocarbons. Hence it is necessary to ensurethat these products are replaced by new, environment-friendly substitutes, and thatrelease into the environment is prevented.

Furthermore, the end of CFC production and the ban on their use require a solution tothe problem of disposing of the CFC quantities in refrigerators, foams and stores. Inorder to protect the environment, it must be ensured that the stored quantities are,wherever possible, collected in leak proof containers and disposed of with due care forthe environment. In this regard it must be guaranteed that no new exhaust gas or wasteproblems arise when the CFCs are destroyed. A low-residue circulatory system shouldbe aimed for.

Collection system

Recover of CFCs necessitates a close co-operation between CFC producers,refrigerant trade, refrigeration plant builders and CFC collectors. It’s of great importanceto have a countrywide disposal system. The removal techniques must be developedfurther, so that during maintenance and dismantling work, the refrigerant can becompletely removed without loss.

By effective training of the persons handling the materials, it is necessary to increase theenvironmental awareness in addition to imparting special knowledge.

Secondary recycling

For refrigerants, which are no longer allowed to be reconditioned following the ban onCFCs, environment-friendly decomposition processes are called for. Basically, the aimis to decompose CFC’s and achieve a material recycling at a high product level, socalled secondary recycling, and to avoid incineration.

This process is also helpful to reduce exhaust gases of fluorine chemical plants (e.g. R23). Instead of releasing the non-condensable parts into the atmosphere the exhaustgases will be fed into a decomposition facility to recover especially hydrogen fluoride.


The decomposition process

For refrigerants, which are no longer allowed to be reconditioned following the ban onCFCs, environment-friendly decomposition processes are called for. Basically, the aimis to decompose CFC’s and achieve a material recycling at a high product level(secondary recycling) and to avoid incineration. The problem was solved by developinga special high-temperature hydrolysis process in which the CFC molecules are crackedby heat and hydroxyl radicals into smaller units, in order to obtain new valuablechemicals for sale.

Chlorofluorocarbons are noted for their high degree of stability. Cracking of CFCs intosmaller units is only possible with a high energy in-feed.

The optimum method of generating high cracking temperatures was determined inseries of tests. It was found that even at temperatures of about 1,000°C, not all the CFCgrades could be decomposed.

The CFCs with a hydrogen content reacted considerably better than the perhalogenatedcompounds such as CCl2F2 (R12) and CClF3 (R13) or C2Cl3F3 (R113).

The decomposition proceeded much more efficiently when the CFCs were fed into ahigh temperature flame (1800-2200°C). The optimum heat source was shown to be theoxy-hydrogen flame H2/02 irrespective of grade, and thus of the CFC/HFC mixture. Thecracking process is not an incineration process. The hydrogen/oxygen flame is used asa heat source and as a source of water steam. The cracking process is a high-temperature hydrolysis process. The decomposition efficiency under these conditions isover 99.999 %.

Equipment design

The CFC cracking reactor consists of a reaction chamber and a heat exchanger flange-mounted directly beneath.

The cylindrical reaction chamber is protected by a water-cooled steel pressure jacket. Aspecial burner for hydrogen, oxygen and CFC is flange-mounted at the upper front-endof the reaction chamber. The reaction chamber is made of graphite and must beprotected from overheating. Since the flame is not in direct contact with the inner reactorwall, with the jacket cooling system an inner wall temperature of approx. 60°C isachieved in spite of flame temperature of over 2,000°C. The heat exchanger in blockconstruction flange-mounted directly beneath the reaction chamber is also made of acidproof graphite and surrounded by a water-cooled steel pressure jacket.


The CFCs fed into the oxy-hydrogen flame are cracked into hydrofluoric acid,hydrochloric acid, carbon dioxide, water and small amounts of chlorine. In the heatexchanger, the degradation products are cooled to a level where at the outlet an approx.60 % aqueous hydrofluoric acid and the incondensable gases can be removed.

In the downstream columns of the cleaning facility, 55 % hydrofluoric and 31 %hydrochloric acid are obtained in saleable quality. During the subsequent exhaust gaswash, remaining acid traces are washed out with water and the slight chlorine contentremoved by feeding in SO2 or sodium bisulphite. The wastewater is passed to awastewater cleaning plant. After these cleaning steps, the exhaust gas conforms to thepurity requirements of the German Clean Air Regulations (TA-Luft). The formation ofpolychlorinated dioxins and furans is reliably prevented by the high crackingtemperatures of over 2,000°C and the subsequent rapid cooling of the degradationproducts to approx. 40°C. No solid wastes are produced.

Once a year the exhaust gas concentration is checked by the German EnvironmentalProtection Agency –TÜV-.

As reusable products from the decomposition of CFCs 55 % hydrofluoric acid and 31 %hydrochloric acid are obtained in saleable quality from the degradation products. Sellingof HF 55 % is very important to the profitability of the process.

Customers are: Glass industryHF manufacturersSteel processing and chemical industriesBleaching earth manufacturersDye manufacturersAsbestos disposal firms

Experiences

Since 1983 the CFC-decomposition plant is on stream at the SOLVAY site at Frankfurt,Germany. Two cracking reactors for CFCs are in operation. The first cracking reactorwas put in operation to reduce the exhaust gases of the CFC-plant in 1983. Since 1987the cracking plant has been used to decompose spent CFC’s/HCFC’s. The crackingcapacity of each reactor is 200 kg/h. Up to now an amount of approximately 7000 mt ofCFC/HCFC /HFC’s has been decomposed. Approximately 7000 mt of hydrofluoric acid55% and approximately 7800 mt of hydrochloric acid 31% have been recovered forselling. The hydrofluoric acid 55 % recovered by this process is a clear liquid of bestquality.

Due to use of graphite as construction material for the reactor there is no corrosion formany years of operation. Only once a year the metallic burner has to be changed for anew one. The plant is in operation more than 8000 h per year. Up to now experienceswere gained based on more than 100,000 hours of operation. The CFC cracking plantis automatically controlled by a process control system located in a control-room.


Sometimes there is a need for a CFC decomposition plant but it may occur that at thelocation no hydrogen and oxygen is available. To meet this situation we have developeda new type of burner and a new reactor where the flame is stabilized in a porousmaterial. Such a burner operates with natural gas and air.

Conclusions

Our environment can be better protected if material loops modelled on nature arecreated. Normal incineration of CFC products should be avoided.

The SOLVAY CFC CRACKING PROCESS is up to now the only process that allowsusing CFCs as a raw material to produce hydrofluoric acid and hydrochloric acid forsale. Therefore it’s allowed by the regulations to take-back CFCs also from othercountries as feed-material for the cracking plant to produce hydrofluoric acid andhydrochloric acid.

The result of the world-wide phase-out of the CFC technology depends on how quicklyand successfully the developing countries, too, can adopt the measures taken by theindustrialized countries. A close co-operation with know-how transfer between industryand developing countries permits the introduction of new recycling systems and thechangeover to refrigerants of the new generation. In this regard it is necessary to ensurethat from the outset the products are handled in a material loop.

SBU Fluor

[email protected]

Cracking Capacity 200 kg/h (R 12)g a se o us o r liq uid fee d

Raw m aterials

O xy ge n 6 6 nm3 /hHy dro ge n 1 1 0 nm3 /h

Utilities

C o o ling w a te r 5 0 m3 /hE le c tric po w e r 5 0 kW

SBU Fluor

[email protected]

Recovered Products(Decomposition of 200 kg/h R 12)

Hydrofluoric acid 55 % 120 kg/hyield 99 %

390 kg/ hHydrochloric acid 31 %

yield 96 %

Quality

Hydrofluoric acid 55 % by wt.HCl < 3 %

Hydrochloric acid 31%HF 10-1000 ppm

SBU Fluor

[email protected]

By-products and EffluentsGerm an Clean Air Regulation TA-LuftThe waste gas com position is well within this regulation

HF < 5m g/m 3

NO2 < 0.5 g/m 3

HCl < 20 m g/m 3

Dioxin and Furans < 0.1 ngHydrofluorocarbon < 150 m g/m 3

CO < 0.1 g/m 3

SBU Fluor

[email protected]

By-products and EffluentsReal Plant Num bers

HF < 0.23 m g/m 3

NO2 < 0.5 g/m 3

HCl < 0.2 m g/m 3

Dioxin and Furans < 0.003 ngHydrofluorocarbon < 2.9 m g/m 3

CO < 0.047 g/m 3

W aste water approx. 400 kg/h (with little Na2SO4, NaCl)

SBU Fluor

[email protected]

Capital and operating costsdepend on a high degree on the infrastructure of the location

For German Conditions we can assume as follows:

Decomposition plant capacity 1600 mtons per annum with

o 1 reactoro cleaning facility (HF 55 %, HCl 31 %)o tankfarm

Investment approx. $ 4 MioOperating costs $ 1-2 / kg depending on grade

SBU Fluor

[email protected]

Experiences in destroying ODSmore than 100,000 hours of operation

Cracking plant at Frankfurt/ Germany

Start up 1. reactor 1983Capacity200 kg/h R 12

Start up 2. reactor 1987Capacity200 kg/h R 12

Total amount of

CFC/HCFC/ HFC decomposed approx. 7000 mt

recovered HF 55 % approx. 7000 mtrecovered HCl 31 % approx. 7800 mt


6.5 Vitrification Process for ConvertingODS to Glass

Mr. Fredric Schwartz, United States

Presentation Vitrification Process for Converting ODS to Glass

Pure Chem, Inc. has recognized the need to effectively treat and dispose of halogenated organiccompounds without creating additional by-products that might present a negative environmentalimpact. Historically incinerators and other thermal destruction devices have been utilized todestroy these materials but in all cases generate additional by-products that require some formof disposal be it a landfill for the resultant ash or a sewer system for the neutralized halide saltsolution. Both of the resultant by-products present additional potential problems requiring eitherconstant monitoring of landfill leachate for the ash or the risk of a salt imbalance in the seweragetreatment plant effluent that could materially present a negative impact to marine life as a resultof having to discharge the salt solution. In addition products of incomplete combustion or PIC’s,formed in the incineration process are typically vented to the atmosphere as carbon monoxidethrough a stack. Even the discharge of significant amounts of carbon dioxide as a result of thisprocess can also present a negative environmental impact.

Recognizing the serious problem impacting the ozone layer as a result of the release ofChlorofluorocarbons(CFC’s), Hydrochlorofluorocarbons(HCFC’s) and Halons to theatmosphere, Pure Chem explored the potential of developing a process that will improve onpresent destruction methods while meeting the long range environmental objective of minimizingthe discharge of hazardous waste products. In addition it was the intent of Pure Chem to beable to manufacture a product through this process that could then be returned to commerce,hence accomplishing the objective of recycling waste materials. The result was the developmentof the patent pending technology referred to as “Method of Converting HalogenatedCompounds to Glass”.

In developing this process Pure Chem evaluated numerous existing destruction and conversiontechnologies that might be combined to accomplish the processing objectives. After anexhaustive evaluation program it was decided to incorporate the use of a plasma arc systemcombined with a glass melter to accomplish the objective. The rationale being that bothtechnologies had a proven environmental success record. Specific research into glass formingtechniques indicated the introduction of calcium phosphate as part of the formulation wouldsignificantly enhance the ability to encapsulate the halide salt slurry into the resultant glass matrix.Halides, most specifically chlorides exhibit a low affinity to encapsulation into a glass matrixthrough conventional formulation.

Additional concerns centered around the potential formation of dioxins during the thermaltreatment phase. The potential of forming 2,3,7,8, Tetrachlorodibenzodioxin, which can beformed during the incineration process in the presence of chlorine and oxygen was a majorconcern. Relying on data provided by the Department of Energy indicated that the destruction,i.e. conversion efficiency of the higher temperature thermal treatment systems, significantly

reduced the potential formation of this carcinogenic compound. The following chart exhibits the destruction or conversion efficiency of similar halogenated compounds:

Compound % Destruction EfficencyChlorobenzene 99.99986Methylene Chloride 99.9995Carbon Tetrachloride* 99.99988

• primary building block of many refrigerants

The rationale behind converting these ODS’s to glass is its chemical resistivity. This ensures thatthe resultant by-products of the conversion process will be encapsulated into the glass matrixand not present a potential environmental impact. History has proven that this intense resistivityof glass to chemical attack is real as a result of the discovery of glass artifacts estimated to bemany thousands of years old that are fully intact. As an example are the studies done onnaturally formed glasses that are estimated to have formed in excess of one hundred millionyears ago. Although these glasses are relatively low in silica content there appears to be littleevidence of physical or chemical attack. Many glass samples have been evaluated that haveexisted in all types of chemical environments where the estimated corrosion rate is less than 0.1inch per million years. The purpose of this data is to provide the necessary confidence factorthat the vitrified product produced from the conversion of these refrigerants and halons will alsoafford the environment the maximum level of protection.

Advantages of Converting Refrigerants to Glass:

1) Encapsulates and immobilizes the entire spectrum of CFC’s, HCFC’s and Halons into achemically resistant and completely durable rough glass frit that can be further manufacturedinto a commercially viable product.

2) Destroys halogenated organic materials through the dissociation of the halogen molecule(s)and thermally converting the carbon portion through pyrolysis.

3) Provides high volume waste reduction.

4) Converts essentially all secondary wastes to a raw material feedstock for conversion intorough glass frit product.

5) Generates little or no secondary wastes through scrubbing the off gas and recycling back tothe glass melter.

6) Will convert virtually all halogenated organics not necessarily only refrigerants and halons.

7) Long term durability of vitrified product.

The Pure Chem process in Stage One initially thermally separates the gas into its originalbuilding blocks, carbon+hydrogen+halogen. By operating at a constant high temperature, 1000-1750 degrees Centigrade, the system will ensure the destruction and prevention or reformationof complex pollutants. Any acid gas is captured and neutralized in an alkaline scrubber bath.The resultant pyrolysis product gas that consists of hydrogen and carbon monoxide can bereturned to the system as an energy source.

A specially designed feed system is to be utilized to feed the refrigerant as a gas. As a result ofthe high operating temperature in the processing chamber the refrigerants will quickly dissociateinto carbon, hydrogen, chlorine and fluorine. The elements will then form simple gases that arestable at these operating temperatures, hydrogen, carbon monoxide, carbon dioxide, hydrogenchloride and hydrogen fluoride. There may also be present small amounts of other gases such asnitrogen or air. In the presence of air the potential formation of NOx compounds occurs butare easily mitigated through the strongly reducing environment that is typical of pyroliticreactions. This rapidly will convert any NOx to gaseous elemental nitrogen.

The pyrolysis product gas formed from the refrigerant and/or halon feedstock is piped to aquench system prior to the gas scrubber where the resultant acid gases are neutralized and anyparticulates removed. The fuel gas consisting of hydrogen and carbon monoxide can then beeither recovered as an energy source or further thermally oxidized to carbon dioxide and watervapor. Pure Chem has chosen to integrate an oxidation step to convert any carbon monoxide tocarbon dioxide in order to utilize this by-product to react with calcium oxide to form acarbonaceous lime feedstock for the glass manufacturing process in Stage Two.

In Stage Two the mixed brine slurry, consisting of calcium chloride and fluoride salts along withrecovered carbon dioxide is then combined with specially formulated other glass makingreagents into a homogeneous melt utilizing a vitrification device. This device is a joule heatedceramic melter. There are several primary glass making raw materials that can be used invarying concentrations to form the most stable glass frit product. Typically utilized raw materialsare silica sand with a minimum 99% silicon dioxide purity level, crushed washed and screenedto ~20 to 200 mesh, sodium carbonate to yield sodium oxide at ~20 to 200 mesh, limestone orburnt lime to yield calcium oxide and magnesium oxide which when further reacted with carbondioxide forms calcium carbonate, feldspar to yield oxides of aluminum, silica, sodium andpotassium and other oxides as required. Do to the inherent low levels of halogen solubility intraditional glass it was determined that by introducing a source of phosphate as calciumphosphate there would be a significant increase in both the solubility of the chlorides andfluorides.

This is a batch process since the concentration of halogen salts will vary based on the initialcomposition of the feedstock to Stage One. As such the raw material mixture is heated in theglass melter at a temperature of 1500 Degrees Centigrade. Which causes the reaction resultingin the formation of a rough viscous glass frit product. Any off gas such as carbon dioxide isdrawn off to a quench scrubber wherein the gas is passed through a roughing filter and through a

heat exchanger. Finally the gas passes through a HEPA filter and then discharged through astack. The resultant glass frit is cooled to 1300 Degrees Centigrade and then pressed or rolledinto the final glass frit product for sale to the glass manufacturing industry as a feedstock.

Based on the anticipated types of refrigerants and halogens to be processed Pure Chem hasdetermined the charge for converting these materials to glass to be in range of $1.00-$1.50U.S.D. per pound. This price is consistent with the charges levied by hazardous wasteincinerators for similar services. Pure Chem does anticipate providing to its customers a rebatebased on the value received from the sale of the glass frit product. This rebate will be net of anydistribution expenses incurred by Pure Chem. The actual rebate will be calculated on a quarterlybasis and will ratio pounds received by the individual generator as a percentage of the totaldivided into the net revenue received from the glass frit sale.

Presently Pure Chem does not operate any facilities for the conversion process. Presentlynegotiations are underway with financing sources to raise the initial $3,000,000 to build theprototype system. We feel confident in the efficacy of the technology based on the fact that themajor components of the technology are well proven in similar types of treatment applications.During this period Pure Chem will continue to work with glass making experts to furtherenhance the solubility of the halogen slurry into the final glass matrix while concurrently notimpacting negatively the costing structure.

Based on the world wide ODS problem Pure Chem anticipates making this process availableon a global basis in the next few years. We feel that with the accelerated phasing out of ODSthat our timetable for commencing with the prototype constuction will ensure that our ODStreatment technology will be available to the world market.


6.6 High Temperature Coincineration

Mr. Werner Wagner, Switzerland

Destruction of ODS through high temperaturecoincineration

Introduction

Ladies' and gentlemen,

It is the goal of this presentation to demonstrate how coincineration can beused to dispose of ODS and what side effects this solution has.

In coincineration, existing, suitable hazardous waste incinerators are used todestroy ODS along with other hazardous waste.

Destruction of ODS through coincineration

The sun’s high energy UV light energizes the ODS molecules, causes them tobreak apart and interact with the ozone in the stratosphere.

A similar process happens in a hazardous waste incinerator, when ODS areintroduced into it. It is not the UV light but the IR rays from the fire insidethe hazardous waste incinerator (1100-1600 ° C) which start the break down of the ODS molecules. The highly reactive crack products will subsequentlyreact with oxygen and hydrogen atoms present in the incinerator . Thusduring the passage through the fire, the ODS molecules are converted tovarious simple compounds, which can be readily removed from the flue gas.Incineration destroys the ODS and therefore effectively prevents furtherpollution of our biosphere.

The maximum possible destruction of ODS through incineration is onlyachieved if the following conditions are under permanent control :

Temperature (> 1100-1250°C average flue gas temperature)

Excess Oxygen ( 6-12 %)

Residence time of the flue gas in the hot and cold zone

Presence of organic waste or primary fuel

The ODS Disposal Chain - Coincineration Technology

The ODS Disposal ChainBefore we enter deeper into incineration and it’s technology, let us followthe ODS life cycle from cradle to grave. In the disposal chain view, theproduction and application of ODS in Products will not be considered. Thedisposal chain starts at the owner who has an ODS containing waste and isfaced with the disposal thereof - and ends, when the ODS has beensuccessfully incinerated. The following steps have to be taken :

Transport to the Recycler

Recovery of ODS at the recycler’ s workshop

Transport of ODS to the hazardous waste incinerator

Coincineration of ODS

Disposal of residual wastes

We have to bear in mind that at each step in the disposal chain, some ODCmaybe lost and can enter the atmosphere. But let us focus now on thecoincineration of ODS delivered to Valorec AG for incineration.

The kind of ODS Valorec AG incinerates are mainly the Freons R11 and R12and the Halons 1301 and 1211.

Prior to the incineration the delivered, mostly pressurized vessels containingthe ODS in a liquid state have to be connected to the feeding stations of theincinerator. There is a rich variety of pressure vessels and manifolds.

Once the pressure vessels are properly connected to the system the actualfeeding of the ODS into the incinerator can start. Feeding of a pure liquifiedgas or liquid is normally very easy, if done according to the state of the art.Many times however, and especially in the case of Freons, the pressurizedvessels do not only contain Freons or a mixture thereof, but also water, oiland sometimes even particles from plastic foams, leading to all sorts ofdifficulties like clogging up of valves and tubing. System clog up’s willautomatically cause higher incineration cost.

The operators of Valorec AG’s incinerator are all professional mechanics whoare able to make adapters at short notice. They do also have the skills toopen tanks and exchange defective valves etc. This is an additional service,provided to the customer free of charge.

Coincineration Technology

Coincineration is a straight forward process. The ODS are fed into theincinerator at the front of the rotary kiln as a gas. The ODS gas is then forcedto pass through the high temperature zone in the kiln. The total time spentin the rotary kiln is estimated to be in average 2 to 3 seconds. The heatimpact is so fierce, that the ODS molecules are at least severely crackeddown to highly reactive crack products. These start to react with oxygen andwater vapors present in the kiln. The Temperature at the hottest position arein the range of 1400 to 1600 °C. The flue gases will then enter into a largepost combustion chamber where they are exposed to a prolonged heattreatment of 2-4 seconds at 1100 to 1200°C. Upon passage through the postcombustion chamber the degradation of the ODS molecule is nearlycompleted. The typical cmbustion products from ODS such as HCl, HF,HBr,Cl2, Br2,CO2, CO together with small amounts of unburnt ODS will leavethe hot zone with the flue gas and are cooled down to 250 °C in the boiler. Inthe quench tower the flue gases are cooled down to 50-75 °C in a very shorttime. Time for recombination of the combustion products to halogenatedDioxins or Furanes is therefore limited through the time available for theundesirered reaction to take place and the scarcity of rectants.

Strong acids such as HF, HCl are already absorbed in the quench stage to alarge extent. To a very small extent unburnt ODS is also absorbed in thescrubbing liquid. Elementary halogens are reduced to the correspondinghalides through reductive chemisorption.

Finally the DeNOx catalyst will oxidize traces of unburnt organic compoundswhen the flue gas passes through the catalyst bed.

Fluorides, are separated from the wastewater stream through precipitationwith lime.

The filtered off Calcium Fluoride can be deposited in a special landfill.Bromides and Chlorides are emitted through the effluent water as solublesalts and will find their way through the rivers back to the sea.

The small fraction (0.007 to 0.21 %) of unburnt ODS will be emitted throughthe flue gas directly to the atmosphere. The carbon in the form of CO2 entersthe atmosphere through the flue gas.

Thermal destruction efficiency for ODS achieved inValorec AG’s hazardous waste incinerator

At Valorec AG a former CIBA and Novartis Company 4 trials were carried outto determine the destruction efficiency for ODS.

1. Halon 1301, R 1211 1992 rotary kiln type incinerator2. R11,R12 1996 rotary kiln type incinerator,measurement of R11,R12 dissolved in Scrubber liquids were carried out aswell

The following destruction efficiencies were observed:

Halon 1301 (CF3Br) 99.994 % of Input

Halon 1211 (CF2BrCl) 99.993 % of Input

Freon R11 (CFCl3) 99.95 % of Input

Freon R12 (CF2Cl2) 99.79 % of Input

The Swiss ODS Disposal Market

The Swiss ODS disposal market presently yields a maximum of 250 t/a ofFreon R11/R12 per year. Because the use of ODS is prohibited a sharpdecrease is expected in the years to come. Similar Halon 1301 and 1211currently held stock in stationary and mobile firefighting equipment isestimated to be 500 t only .

So far Valorec AG has incinerated 30-45 t of Freons and some Halonsannually.

The market price range is

4.5 to 7 Fr/kg in the case of Freons

12 to 18 Fr/kg in the case of Halons

To our knowledge coincineration is the only disposal method applied inSwitzerland. Some polyurethane foam though is most likely directlyincinerated in municipal incinerators. Given the expensive cost structure ofthe small Swiss Hazardous Waste incinerators, it is not surprising that theSwiss market prices are well above the ones of it’s global competitors.

Summary & Conclusion

Weaknesses of coincineration :

Coincineration is relatively expensive, due to the high fixed costs ofincinerators

The destruction efficiency is not 100 %

Only high-tech hazardous waste incinerators with controlled performance andan appropriate flue gas cleaning system can be used for coincineration

Strengths of coincineration :

The technology is available i.e. existing hazardous waste incinerators can beused for the disposal

Only small investments are necessary, no additional financial risk to bear

Only a small amount of additional primary energy is needed

The process is very flexible and tolerates mixtures of ODS. Coincineration canalso be used for other substances causing global warming, such as SF6.

Conclusion :

Coincineration is a viable proven tool for the destruction of ODS.Coincineration removes ODS from the biosphere effectively and thereforeprevents further pollution of the stratosphere.

Werner WagnerValorec AGPostfach 1184019 BaselSwitzerlandTel. +41 61 468 86 55Mob. +41 76 321 43 43Fax : +41 61 468 86 60e-mail : [email protected] site : www.valorec.ch

• Temperature Range 1000-1200°C

• Residual Oxygen 6-12 %

• Flue Gas Residence Time in the Hot Zone 4-6 s

TimeHigh

Temperature

Excess Oxygen

Special Waste

Valorec AG

Incineration - Factors to control

• National and international environmental laws and regulations

• Awareness, will and economic power of the owner to comply with

the law

• Access to appropiate destruction technology

Ownerof waste

Transport Recycling Transport Logistics &Preparation

Incineration

Treat -ment ofresidualwastes

Valorec AG

The disposal chain for ODS in Switzerland

Freon extraction equipment at the recyclers workshop

Valorec AG

Freon extracted from Plastic Foam

Valorec AG

Pressurized Vessel for R12/R11 400 kg net

Valorec AG

Recovery and Recycling of Metal and Plastic parts

Valorec AG

Freon pressurized Vessel Filling station

Valorec AG

Pressurized Tanks containing Halon 1301 from phased out Fire Extinguishing Equipment

Valorec AG

Tanks containing R12/R11

Valorec AG

Find a suitable Adapter and the Job is half done

Valorec AG

Roll- Tank containing R12/R11 400 kg net

Valorec AG

Solid Waste

Liquid waste,fuel, air

1'200 C°4,0 s

Steam

250°C

fuel, airliq.waste

Rhine river Rhine river

1'000 - 1'200°C

2-3 s

Wastewatertreatment

Wastewatertreatment

Coincineration of ODS at Valorec`s Hazardous Waste incinerator

Emissioncontrol

Valorec AG

Catalyst

MultistageScrubber

Destruction of Halon 1211 through Exposure to Fire

CF2ClBr Br*HBr

Br2

CO

CO2Cl*

Cl2

HCl1100-1250°C

6-11 % O2other combustible waste containing H and CTime 4-6 s

F*

HF

Valorec AG

Destruction Efficiency for Freons and Halons

Halon 1301 (CF3Br) 99.994 %Halon 1211 (CF2BrCl) 99.993 %

Freon R11 (CFCl3) 99.95 %Freon R12 (CF2Cl2) 99.79 %

Valorec AG

Sources : Ciba Forschungsdienst FD 241.96.629D Freon R11/R12 Ciba Forschungsdienst FD L29-92 Halon 1301, 1211

The Swiss Freon Disposal market source : S.EN.S)

1995 2000 2005 2010 2015 2020 2025

250'

2030

t/a

125'

R11/R12

VOC

R 134a

Valorec AG

Valorec AG

The Swiss Halon Disposal market

It is estimated that there are currently around 500t ofHalon 1301 and 1211 in Switzerland awaiting disposal.

Valorec AG

The Swiss ODS Disposal Market

The market price range for coincineration is :

4.5 to 7 CHF/kg for Freons12 to 18 CHF/kg for Halons

Valorec AG disposes of around 45t/a of freons and halons.

Conclusion

Coincineration is a viable proven tool forthe destruction of ODS.

Coincineration removes ODS from thebiosphere effectively and thereforeprevents further pollution of thestratosphere

Valorec AG

6. technology presentations 6.3 alternative plasma ... · 2 table 2 freon destruction with the 15...

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