Plasma Arc Science and Technology
   

Plasma was developed over a hundred years ago, but extensive work with materials other than industrial high temperature metallurgical applications did not occur until work was needed to simulate re-entry temperatures on the heat shield of re-entry vehicles in the late 50’s and 60’s. Recently, this technology has begun to emerge as a commercial tool in several industries, i.e., steel making, metallurgy, precious metal recovery, and waste disposal.

Most of the research and testing with plasma was done with a plasma torch. A plasma torch is a device that converts electrical energy into thermal energy (Camacho, 1998, 1991).  Plasma is an ionized gas that is conditioned to respond to electromagnetic forces.  The plasma arc is created when a voltage is established between two points.  The plasma acts as a resistive heating element and as a resistive heating element it presents a distinct advantage over any solid heating element as plasma is a gas and cannot melt or fail.  The plasma arc creates a “flame” that has temperatures ranging from 4,000 to 7,000 ºC, which is hotter than the surface of the sun.  Thus, plasma torches operate at much higher temperatures, higher enthalpies, and at efficiencies much greater than those of fossil fuel burners.  In addition, plasma torches require only about 5 percent of the gas necessary for fossil fuel burners; therefore, waste effluent gases are greatly reduced.  Because of this factor, reactor systems can be built that are much more compact than traditional furnaces, at correspondingly reduced capital costs.

Several plasma arc torch and/or solid electrode systems and processes for the destruction of a variety of waste materials have been developed, successfully tested and implemented.  The very high temperatures and energy densities, in conjunction with the ionized and reactive medium, have fully demonstrated the potential of plasma arc technology to eliminate many waste materials in an environmentally safe and cost-effective manner.  Materials vitrified in atmospherically controlled reactors with Plasma Technology readily pass all standard EPA leaching tests.

The process of utilizing plasma generators to thermally dissociate waste materials and convert these materials into re-usable products is distinctly different from combustion (incineration) in that it uses energy from plasma to thermally convert organic waste from a solid or liquid to a gas through a process called controlled pyrolysis or controlled gasification.  The constant high operating temperatures ensure the complete destruction of all complex organic compounds, and the process control minimizes the possibility of reformation of a complex pollutants and hazardous gases.  The escape of volatile metals and acid gases is also minimized to levels that have met the most stringent air emission standards.

The key elements in the destruction process are the ATONN Plasma Gasifier Feed System and the Controlled Atmosphere Reactor.  Both proprietary systems ensure the complete control of the pyrolytic process beginning with the precisely controlled introduction of feedstock into the reactor.  The ATONN processes is essentially  endothermic.

Municipal Waste Destruction and Production of Electricity:

The ATONN Plasma Conversion System exploits the unique capabilities of plasma generating systems by integrating them with associated technologies to realize the latent value assets in the municipal solid waste stream. Plasma Generating Systems have, at their core, the capacity to dissociate compounds into elemental atoms. Once the atoms are feed to move independently, simple chemistry is applied to reassemble the atoms into usable, commercially viable products. S.A.A. brings a number of proprietary technologies involving thermal plasma that through their unique application provide the most efficient method of generating synthesis gas. The important difference between the ATONN Plasma Conversion System and other plasma designs is our ability to deliver municipal solid waste into the reaction chamber not only without air, but also in a continuous, controlled supply at controlled density and in a large volumes (2000, 3000 or 4000 tons per day). This ability results in a superior synthesis gas product with higher Btu energy value but also makes the process economically feasible because solid municipal waste disposal requires the ability to process not pounds but tons per hours. The organic content of average municipal solid waste will dissociate or thermally depolymerise into 30,000 to 33,000 cubic feet of synthesis gas per ton, having an energy value of 300 Btu per standard cubic foot of gas. The heat rate for ATONN combined cycle power generating system is expected to be about 7.277 or lower, generating 1,360 kW per ton of municipal solid waste that is processed. The processing of 1000 tons of municipal solid waste per day or 41 tons per hour will release 1,353,000 cubic feet of synthesis gas per hour with a total Btu value of 405,900,000 Btu/hr. At a heat rate of 7,277 the ATONN combined cycle gas turbine system will generate a gross of 55.76 Megawatts of electricity per hour, twenty‑four hours a day. When we deduct 26 Megawatts of this electric current to maintain the plasma arc and for other plant requirements, we are left with 29.76 Megawatts per hour (714.24 Megawatts per day) available to supply the grid.

Relevant Experience of Power Generation Utilizing Synthesis Gas:

In it’s projects currently in development, the ATONN technical team will utilize General Electric gas turbines (however, some other heavy frame and aero derivatives can also be used). GE brings over 600,000 hours of operation on syngas, clearly enough to establish that the basics of syngas utilization in combustion turbines for electric power generation in simple or combined cycle modes are doable. In fact, in Europe over eleven Gigawatthour of power are produced using syngas. Most of this is from conventional gasification methods. The main reason this has not been common in North America is that natural gas here has been in the past been readily available and inexpensive. As natural gas prices increase, gasification will become more attractive. Plasma gasification offers the best alternative as the least expensive and most versatile of the available systems. GE’s success with low and medium Btu fuel gases is a consequence of extensive full‑scale laboratory testing on various fuels for over 15 years at GE’s Combustion Development Laboratory in Schenectady, New York. S.A.A. has full access and rights for the implementation of this technology from patent holder.

Description of the ATONN Plasma Conversion System for MSW:

Dual Graphite Electrode Technology (Patent applied for):

ATONN brings proprietary plasma generation technology consisting of a rugged, outer shroud for pressure containment, the electrodes, a vortex generator, and insulators. The typical shroud has an outer diameter of approximately 20 feet and is constructed of carbon steel with an internal insulation and refractory lining resistant to the environment of the process vessel. Each gasifier will include one or two plasma arc assemblies, each sized to provide the required power to achieve the maximum energy required for materials dissociation. Electrodes are fabricated from carbon graphite materials providing improved electrode life. ATONN’s graphite electrode technology has been successfully proven over many years of commercial operation in the metallurgical industry and typically has an availability rate of greater than 90 percent.

Plasma Gasifier Feed Systems (patent applied for):

ATONN brings a proprietary feed system, one for municipal solid wastes and conventional carbonaceous wastes and one possibly consisting of a pressure compensation feeder for medical wastes. The system ensures the highest efficiency in the feed rate and is designed and engineered to prevent the introduction of extraneous air into the gasification chamber (a very important element of the plasma gasification process). The system consists of a compactor/extruder integrated with waste feed containers and a conveyor system that will introduce the waste feedstock into the gasifier.

The following is an example of how municipal solid waste would be processed into our plasma conversion system.

The waste feedstock is delivered and discharged by truck or other means to the “tipping floor”. A pre-crusher compacts and densifies the waste into a specially designed compaction container.  Once filled, the container is provided with a metallic door that will be closed, thus preventing problems with rodents and foul odours.  An overhead crane or conveyor system then moves the filled containers into the gasifier area.  This will allow efficient control of the process and will ensure that there is no chance that a filled container can be “forgotten” (a major cause of rodent and odour problems in MSW facilities).

Once the container reaches the gasifier, a small crane will place the container into the gasifier‑feeding platform (after removing the empty container previously fed into the system).  The empty container is placed in a second conveyor that will return it to the container area.  The feeding platform is an articulated tilting “table” where the container door is opened.  Once the door is opened, the articulated “table” is inclined approximately 60 degrees directly over the compactor/extruder, which then feeds the MSW into the gasifier.  The compactor/extruder that is provided, in conjunction with the storage container, provides a unique advantage that maximizes the unique benefits of plasma gasification of MSW.  Firstly, the system feeds the waste feedstock into the gasifier after having extruded a significant portion of the entrained air in the waste feedstock (the most important aspect to ensure the production of the highest quality synthesis gas).  Finally, the feed rate can be adjusted and controlled in essentially an infinite manner thus allowing their feed rate to equal the rate of dissociation and gasification within the gasifier chamber.

The graphite electrode Plasma Gasification system brought by the ATONN technical team builds upon the extensive and very successful commercial experience of graphite arc technology used in the metallurgical industry.  The ATONN system is particularly effective for the conversion of high volumes of carbonaceous wastes particularly MSW, but also tires, pet coke and ASR.  The system briefly summarized above is powered by an electric arc Plasma generated by two or more graphite electrodes that introduce the electric arc through a “slag molten bath” of the waste being processed, i.e. molten slag, [It should be noted that plasma fields can also be generated by DC or AC powered “plasma torches”, however, the use of graphite technology has been extensively used worldwide in a wide range of applications and can provide much larger throughputs than can be achieved with the plasma torch method of generating plasma fields.]

Concurrent with, or independent of, the controlled pyrolysis of organic materials, the ATONN plasma gasification system can melt inorganic materials (glass, soil, metals, and ash) if present.  These components, common in many waste streams, are melted and typically recovered as a glassy slag.  The glass layer serves as a medium for chemically binding many metals in a non‑leachable manner through vitrification.  If large amounts of ferrous and non –ferrous metals are present, the molten material will separate as one or more layers, a glassy layer over a metal alloy layer.  Waste streams that are predominantly metal can usually be processed to promote metal recovery.  This is an important and unique benefit, particularly when processing MSW, but also beneficial when processing tires or ASR.

The processing chamber is heated to the desired temperature (1100 to 1300ºC) before the waste materials are fed into the reactor.  Waste is fed into the processing chamber on a continuous basis.  Organic materials rapidly dissociate into elemental constituents, mainly hydrogen, carbon, oxygen, and depending on the halogenated compounds in the feed stock, small amounts of acid gases.  The elements will form simple gases that are stable at the operating temperatures, primarily diatomic hydrogen, carbon monoxide and hydrogen chloride.  To prevent the remaining carbon from re-associating into a solid, a limited source of oxygen (usually in the form of steam) is introduced through an exact, computer controlled metering system at which time it will form carbon monoxide.  The result is a pyrolysis gas (“Syngas”) composed mainly of dissociation of the organic elements.  Small amounts of other gases will be present, including nitrogen.  Within the strongly reducing environment of the pyrolysis chamber, most NOx is either not formed or quickly reduced to gaseous elemental nitrogen.

The process is not “incineration” as combustion of the material is not occurring inside the gasifier.  Recognition as “not an incinerator” often becomes an issue when a government which bans or puts a moratorium on incinerators cannot accept an application for a permit to construct and operate an incinerator.  Furthermore, the ATONN systems status as “non-incinerator” offers a significant advantage in terms of public acceptance of the technology. 

The position that the ATONN process is not incineration is based on two premises.  One, the process in the chamber that destroys the waste does not fit the definition of combustion, but is instead, pyrolysis.  Two, the by-products of pyrolysis (hydrogen, carbon and carbon monoxide) are different from the products of combustion (carbon dioxide and water) and offers options for chemical energy recovery that combustion and incineration do not.

DESCRIPTION OF PLASMA TECHNOLOGIES:

Plasma technologies include the following:

 

AC Plasma generation Systems – Through a very close working relationship with the Institute of Problems in Electrophysics, Russian Academy of Sciences (IPE-RAS), S.A.A. brings the latest generation AC Plasma Torches as well as a variety of other plasma generation methods. 


“Table Top” Plasma Thermal Treatment and Destruction system   IPE RAS has an ultra-small scale plasma thermal treatment and disposal system to provide small tests and demonstrations and for the terminal destruction of a wide range of hazardous and non-hazardous wastes (organic and in-organic) with a capacity of 10 to 40 kg/hr.  These systems can be used for highly toxic materials where relatively small amounts are destroyed at any time.

“Table Top” plasma gasifier built by Georgia Tech Plasma Lab and the 10 KW and 30 KW plasma generators.

 

 

In-situ Plasma Arc Vitrification System – A technology developed by Dr. Louis Circeo, the patent holder.  In-situ remediation of sites (including landfills) contaminated with hazardous and/or radioactive wastes.  The technology has been successfully proven (and validated by the US Department of Energy) to completely (and in-situ) remediate highly contaminated sites, vitrifying the soil and the contaminants into a totally inert glass matrix (the most stable waste form – in fact a waste form utilized for the permanent immobilization of high-level nuclear wastes).  This method offers unique cost and personnel safety advantages and can provide clients with a unique, cost effective and fast method to remediate contaminated sites.   The in-situ process achieves a major reduction in volume of the materials processed and the formation of very stable soil structures for future construction at the site.

 Graphite electrode systems – This is a variation of the standard arc furnaces used in the steel and specialty metals industry for years whereby the system is converted to a true plasma arc system in lieu of being a conventional Joule heater.  The advantage is in the ability to handle large volumes in a safe and very cost effective manner. 

Plasma Gasifier Feed Systems  – S.A.A. brings a number of proprietary feed system designs for plasma reactors where the feeder allows for the control introduction of materials into the reactor while maintaining control on the environment inside the reactor.  One of these feeders allows for the homogeneous densification of waste and controlled feeding to maintain ideal operating reactor parameters.

INTRODUCTION TO PLASMA GASIFICATION

Gasification of carbonaceous materials has been widely used in commercial applications for many years in the production of fuels and chemicals.  Gasification, particularly of waste materials (such as waste tires, Automobile Shredder Residue (ASR) or Municipal Solid Wastes (MSW)) has a number of important advantages, including: 

 

  1. (1)     the ability to produce a consistent, high  quality synthesis gas product that can be used for energy production or to provide critical feedstock for the manufacture of various products, including plastics and
  2. (2)     the ability to accommodate a wide variety of gaseous, liquid and solid feedstocks. 

 

Gasification of conventional fuels, such as coal or oil, as well as low-value materials and wastes, such as petroleum coke, heavy refinery residuals, secondary oil-bearing refinery materials, halogenated hydrocarbon byproducts have also been successfully used in gasification applications.

 

Gasification of these materials has many benefits when compared with conventional options such as combustion or disposal by incineration.  The US Environmental Protection Agency (EPA) has recently enacted rules that specifically exclude the synthesis gas produced from gasification of hazardous wastes from being regulated as a hazardous waste.  Thus the wide-ranging application of gasification of hazardous and non-hazardous wastes can greatly reduce the need to use fossil fuels for the production of energy and other precursor products for the manufacture of certain chemicals.

Gasification

Gasification is a thermal chemical conversion process that maximizes the conversion of the carbonaceous fuel to a synthesis gas (syngas) containing primarily CO and H2, with lesser amounts of CO2, methane, N2 .and some polycyclic compounds in trace amounts.  The chemical reactions take place in the presence of a reforming agent (i.e. steam, air or pure oxygen) in an oxygen “starved” atmosphere, in contrast to combustion wherein the reactions take place in an oxygen rich, excess air environment.  In other words, the ratio of oxygen molecules to carbon molecules ideally is stoichiometrically balanced in the gasification reactor. 

Pure pyrolysis can also be done in a plasma reactor, with different chemical results.  The following chemical conversion formulas describe, in general, the process for ideal syngas generation:

2H2O + energy → 2H2 + O2

C (feedstock) + H20 (steam, or air or oxygen) + energy → CO + H2  (endothermic)

C + CO2 + energy → 2CO (endothermic)

C + 2H2 → CH4  + energy (exothermic)

S.A.A. brings a number of technologies that utilize the principles of thermal plasma to generate an ultra-high temperature field of ionized gas (i.e. plasma) within the gasifier chamber.  Plasma generating systems have at their core, the capacity to disassociate compounds into elemental atoms.  Once the atoms are freed to move independently, simple chemistry is applied to reassemble the atoms into usable, commercially viable products. 

 

The gasification process is distinctly different from combustion (incineration) in that it uses energy from the plasma to thermally convert organic waste from a solid (or liquid) to a gas through controlled pyrolysis or controlled gasification.  The constant high operating temperature (above 1600ºC) ensures the destruction thermal dissociation of all complex organic compounds, and the process control minimizes controls minimize the possibility of reformation of complex pollutants.  The escape of volatile metals and acid gases can be minimized to levels that meet the most stringent air emission standards.  As the In some thermal dissociation reaction is endothermic, in cases where the organic content of the waste stream is high, the pyrolysis product gas, composed mainly of hydrogen and carbon monoxide, can be used to safely recover much of the energy in the waste.


Concurrent with (or independent of) the controlled pyrolysis of organic materials, plasma gasification systems can melt inorganic materials (e.g. soil, metals-bearing wastes, and fly-ash, metals, etc.), if present.  These components, common in many waste streams, are melted and recovered as a glassy slag. The glass layer serves as a medium for chemically binding many metals in a non-leachable manner through vitrification.  This silicate glass slag can be re-used in commercial applications, including: concrete aggregate, manufacture of rock-wool insulation, roadbed construction and as a construction abrasive. Metals will separate into a heavy metal if the environment is sufficiently reducing.  Waste streams that are predominantly metal can usually be processed to promote metal recovery.  This is an important and unique benefit, particularly when processing, for example waste batteries, heavy metal sludge or Printed Circuit Boards, containing meaningful quantities of valuable metals, and even precious metals such as gold and palladium that can add significant value to such a project.

Key Differences between Gasification and Incineration:

Subsystem

Incineration

Gasification

Combustion vs. Gasification

   •    Designed to maximize the conversion of feedstock to CO2 and H2O

 

   •    Large quantities of excess air are required

 

   •    Highly oxidizing environment

 

   •    Operated at temperatures below the ash melting point; thus mineral matter is converted to fly ash (hazardous) and bottom ash (may be hazardous)

 

  •     Designed to maximize the conversion of feedstock into CO and H2

  •     Limited quantities of oxygen

  •     Reducing environment

 

  •     Operated at temperatures above ash melting point; mineral matter is converted to glassy slag

 

Gas Cleanup

  •     Flue gas cleanup at atmospheric pressure

 

       Treated gas is discharged to atmosphere

  •     Syngas clean-up at high temperatures

 

  •     Treated gas used for energy production on pre-cursors for chemical manufacturing

Residue and Ash Handling

  •     Bottom and fly ash collected, treated (usually through stabilization operations that increase the disposal volume) and disposed as hazardous waste (mostly fly ash)

  •     Slag is non-leachable, non-hazardous and suitable for a multitude of construction applications

Emissions of SOx, NOx and Particulate Matter:

For a given secondary material, emission levels of SOx and NOx, and particulate from gasification systems are orders of magnitude lower than for incineration systems.  In an oxidative incineration environment, sulphur and nitrogen compounds in the feed are converted into SOx and NOx.  In contrast, syn gas cleanup systems for modern gasification systems can be designed to recover 95% to 99% of the sulphur in the feedstock as a high – purity sulphur by-product.  Likewise, Nitrogen in the feed is converted to diatomic nitrogen (N2)  in the syngas.  Any halogens in the feed will turn to acids which are easily scrubbed in conventional systems. 

 

Once the syngas is combusted in an energy production plant (i.e. such as a boiler or gas turbine), the production of SOx and NOx is dramatically reduced.  If the syngas is to be used as a feedstock in downstream chemical manufacturing processes, these compounds are not formed.  Recent US Department of Energy (DOE) Data for re-powering coal-fired electric power plants with Integrated Gasification Combined Cycle (IGCC) technologies has shown that emissions of SOx , NOx and particulate are reduced by one or two orders of magnitude.

Dioxins, Furans and other Organic Compounds:

Typically, organic compound emissions of most concern from waste incineration systems have been Principal Organic Hazardous Constituent (POHC) in the waste feed and Products of Incomplete Combustion (PIC).  POHC refers to the organic compounds present in waste feeds that must be destroyed at greater than 99.99% destruction efficiency (DRE) and in the case of dioxins and furans, greater than 99.9999% DRE, based on US EPA regulations for hazardous wastes.  PIC’s are compounds, such as semi-volatile organic compounds (SVOC’s), polycyclic aromatic hydrocarbons (PAH’s), VOC’s and dioxin/furan compounds (PCDD’s/PCDF’s).

 

Why Plasma Gasification will NOT produce Dioxins and Furans:

 

In a typical combustion (i.e. Incineration Process) when processing materials that contain chlorine atoms, dioxins will typically form.  Dioxin formation typically occurs if the temperatures produced by the combustion process do not exceed 250oC THROUGHOUT THE ENTIRE COMBUSTION CHAMBER.  However, when the chamber temperatures exceed the 250oC threshold, as will typically occur in a plasma gasifier, the chlorinated materials will dissociate itself of the Chlorine atoms and the Chlorine will preferentially combine with Hydrogen to form HCl (which is then removed in the gas treatment system and removed in the scrubber with NaOH to form a benign salt), or if lime is introduced into the gasifier, the Chlorine will combine with the Calcium and be trapped in the silicate slag. 

In order to form dioxins, ALL of the following five conditions MUST be present:

 

1)      Hydrocarbons

2)      Chlorine

3)      A “surface” (i.e. particulate matter)

4)      Copper (the most powerful catalyst), nickel or iron

5)      A temperature range between 250 C to 450 C

In order to prevent the formation of dioxins throughout ANY portion of the gasification system, the synthetic gas produced will be cleaned or filtered at temperatures exceeding 450 C.  The filters will remove particulate matter (#3) (and therefore the binding “surfaces”).  At the same time, the filters will remove metals that can act as catalysts (#4). 

 

In summary, the ATON design PREVENTS the formation of dioxins or furans throughout ANY portion of the gasification process by:

 

1)      Minimizing the presence of Chlorine in the syn gas stream by the addition of lime into the reactor such that the Chlorine will combine with the Calcium and thus be trapped in the silicate slag.

 

2)      Any HCl in the gas stream will be removed by the removal of HCl in the scrubber through the addition of NaOH to form a benign salt.

 

3)      Removal of particulates in the gas stream through filtration

Results from measurements taken in conventional gasifiers confirm that, in general, VOC’s such as benzene, toluene and xylene, when detected, were present in the parts per billion levels.  SVOC’s, including PAH’s, were also detected in the syngas and/or turbine exaust.  SVOC’s were typically present at extremely low levels on the order of parts per trillion.

 

Gasification tests using chlorinated feedstocks have also been conducted to measure the DRE for organic compounds such as chlorobenzene and hexachlorobenzene.  DRE’s greater than 99.99% were demonstrated for both compounds.

 Dioxin and Furan compounds (PCDD/PCDF’s) are not expected to be present in the syngas from gasification systems for two major reasons: (1) the ultra-high temperatures in the gasification process effectively destroy PCDD/PCDF compounds or precursors in the feed and (2) the lack of oxygen in the reduced gas environment will preclude the formation of the free Chlorine from HCl, thus limiting the chlorination of any precursors in the syngas. 

Measurements of PCDD/PCDF compounds in gasification systems confirm these principles.

 

* MACT = Maximum Achievable Control Technology standards for hazardous waste incinerators in the US

 

In all cases, the levels of PCDD/PCDF compounds were one or two orders of magnitude below the most stringent standard recently enacted for hazardous waste incinerators.

 

Trace Metals and Halides

 

US EPA data for hazardous waste incinerator systems indicate that metals emissions include antimony, arsenic, beryllium, cadmium, chromium, lead mercury nickel and selenium compounds.  Acid halides (HCl, HF and HBr) may also be present depending on the halogen content of the feedstock. 

 

Data from a variety of testing done on coal-fired gasification systems have been evaluated.  Based on a compilation of this data, certain trace metals have the potential to be present in the clean Syngas or turbine exhaust.  These metals include:  Chloride, Fluoride, mercury, arsenic, cadmium, lead chromium, nickel and selenium.  In most cases, the amount of these elements present in the syngas or combustion turbine exhaust represented less than 10% of the amount of input to the gasifier (based on coal).  Elements such as Chloride and Fluoride are typically removed in the gas scrubbing and cooling operations and ultimately are removed by the process (i.e. scrubber) water streams; greater than 99% removal of HCl was measured during several EPA test programs.  Semi-volatile metals, such as lead and mercury, will volatilize in the gasifier and re-condense on the fine particulate matter, which is removed from the syngas.  In a plasma gasifier, the addition of lime to the gasifier vessel will promote the entrainment of some of the volatile metals and as much as 90% of the halogens (i.e. Chlorides and Fluorides), entrapping them as Calcium halides within the non-leachable glassy slag.  Analysis of the glassy slag material from various gasification and plasma waste treatment projects (including vitrification of fly ash from incinerators) consistently show that the slag to be non-hazardous according to RCRA definitions.

TYPICAL SLAG CHEMISTRY (MSW Incinerator Fly ash vitrified in a plasma reactor):

 

ELEMENTS

COMPOSITION (% BY WT)

Silica

37.2

Alumina

19.5

CaO

19.5

Fe2O3

6.21

MgO

2.31

Na2O

3.87

K2O

1.31

ZnO

0.24

PbO

0.11

CuO

0.26

MnO

1.70

Cr2O3

0.26

NiO

0.32

CdO

<1

Specific Gravity

1.5 – 2

Volume Reduction

1.88 – 2.5

TYPICAL LEACHATE TEST (TCLP) RESULTS (Vitrified MSW fly ash):

 

SPECIES

MSW FLY ASH FEED mg/l

MSW SLAG mg/l

HAZ WASTE RANGE

Mg/l

INERT WASTE RANGE

Mg/l

Arsenic

0.15

< 0.05

0.2 – 1.0

 

Lead

4.81 *

< 0.05

0.4 – 2.0

 

Cadmium

0.15*

< 0.05

0.1 – 0.5

 

Chromium

0.64*

< 0.05

0.1 – 0.5

Total less than 5

Copper

0.11

< 0.05

2 – 10

 

Nickel

< 0.05

< 0.05

0.4 ��� 2.0

 

Mercury

<0.05

< 0.05

0.02 – 0.1

 

Zinc

0.5

< 0.05

2 – 10

 

Phenols

0.2

< 0.01

20 - 100

< 10

 

* Boldface indicates values that exceed regulatory limits and therefore categorize the feedstock as a hazardous material

TYPICAL SYNGAS COMPOSITION:

 

COMPONENT

CONTENT (VOL% UNLESS OTHERWISE STATED)

H2

32 – 35

CO

34 – 48

CO2

15 – 26

O2

NOT PRESENT

Ar

0.07 – 0.1

N2

0.18 – 5.8 (DEPENDING ON REFORMING MEDIUM USED MAY BE HIGHER)

NOx

NOT PRESENT

SO2

NOT PRESENT

SO3

NOT PRESENT

CH4

60 ppmv – 1930 ppmv

H2S

0 – 7590* ppmv (DEPENDING ON SULFUR CONTENT OF FEEDSTOCK)

* gasification of coal or coal containing feedstock

COS

0 – 176 ppmv (DEPENDING ON SULFUR CONTENT OF FEEDSTOCK)

* gasification of coal or coal containing feedstock

NH3

0 – 0.62 ppmv (after scrubbing and gas cooling)

THC

0 – 27 ppmv

 

Typical heating value of syngas = 300 – 350 BTU/SCF (11.2 MJ/Nm3 – 13 MJ/Nm3)

 

 

Use of Syngas in Electric Power Production

 

The use of low-BTU syngas in combined cycle electric power generating plants has achieved significant success, particularly in terms of significant cost reductions (particularly when the syngas is generated by the processing of waste materials, thus avoiding the cost of purchasing fuel), increased operating efficiency (many gasification /combined cycle projects have achieved ratings of 15% to 30% over natural gas operation) and improved emissions (e.g. lower NOx emissions than with natural gas).  Currently, commercial experience with the utilization of syngas in combined cycle installation total over 350,000 hours,

clearly enough to establish that the basics of syngas utilization in combustion turbines for electric power generation in simple or combined cycle modes.

An average of 20% higher ratings is achieved when operating on low heating value gas (i.e. Syngas).  Fourteen percent difference in flow at same firing temperature drives 28% more output (No Compression Power). However, such high levels of output can be limited by mechanical constraints.



Output Increases

Frame Size MW

MW

 

GT

CC

Syn Gas

6FA

90

107.1

126

7FA

200

262.5

280

9EC

215

259.3

300

9FA

300

390.8

420

7H

 

400

460

9H

 

480

550

 

Plasma gasification systems can produce syngas at a cost that is significantly lower than natural gas or even coal (delivered).  As such, there are significant economic and environmental benefits of utilizing syngas generated by the gasification of carbonaceous waste materials, or coal for the production of electric power or feedstock for chemical manufacturing (i.e. plastics).

These premises are further supported by the following comparisons:

Common Incinerator

Plasma Gasification System

Flame Temperature 1650ºC - 1930ºC

Chamber Temperature 980º‑1370ºC

Arc Temperature 10,000ºC‑15,000ºC

Chamber Temperature 1200ºC‑1600ºC

Results in:

Bottom and fly ash;

Dioxins, Furans;

Nitrogen Oxides

Results in:

Benign silicate glass aggregate;

Recoverable metals;

Reusable Synthesis gas

Significant air required;

Eliminates the ability to generate Syngas

No air Required

Burns large amounts of fossil fuel

No fuels or chemicals; can generate its own electricity effectively

Requires large land area for infrastructure and gas scrubbing

Very compact; has mobile options for smaller systems

 

 

The ATONN Team

The ATONN team brings together a unique combination of the most experienced technical personnel in the field of thermal plasma applications for waste treatment and recycling. ATONN brings a very strong level of experience in the research, development and commercialization of a variety of plasma generation technologies, including AC and DC systems, comprising a wide range of plasma generation technologies, including torches, graphite electrodes, microwave plasma generation systems and radio-frequency (RF) plasma generation systems.

The ATONN team brings the unique capabilities of two of the most renowned plasma research and development facilities in the world:

The Georgia Tech Plasma Research Institute under the direction of Dr. Louis Circeo, (S.A.A. has in place a “Master Agreement for Research Testing and Evaluation with GTRI).

The Institute of Problems in Electro physics, Russian Academy of Science, under the direction of Dr. Phillip Rutberg.  S.A.A. brings the patent rights to several plasma technologies developed by Dr. Rutberg’s Institute.

Both Dr. Circeo and Dr. Rutberg serve as technical advisors to the ATONN team and will provide third party validation and verification of the design and operation of the ATONN system.

Over the past four years, the ATONN team’s technology partners have been successful in obtaining construction and operating permits for plasma waste destruction and conversion systems that incorporate the basic design concept as the proposed future projects, representative permits include:

San Diego, California (the most stringent state in the U.S.):

A permit to construct a plasma waste treatment system to process infectious medical waste generated by several hospitals owned by a major health care corporation.  The plasma technology was also certified as an “alternative to incineration” technology for the terminal destruction of medical waste for the state of California.  This is an important achievement for the technology since California has banned the permitting of incineration for treating hazardous and medical waste.

Indianapolis, Indiana:

A permit to construct and operate commercial plasma waste treatment system to process medical waste and special wastes generated by a major industrial corporation.

Lorton, Virginia:

A permit to construct and operate a 500 kW plasma gasification system (approximately 15 to 20 tpd).  This unit is owned by the U.S. Army Environmental Center and is currently successfully operating.

Results of Independent Tests on Plasma Arc Waste Treatment Technology for Municipal Solid Waste Disposal

Georgia Tech University, one of the most prestigious technical universities in the United States has a prominent plasma arc research program that is the largest based research program for plasma remediation of waste materials in the United Sates (the program is led by one of the pre-eminent authorities in the field, Dr. Louis Circeo, who is a principal technical advisor and consultant to the ATONN team).  This centre has successfully performed a large number of research and independent evaluations of plasma arc technologies for waste management applications.

The following provides a summary of results of experiments on the use of plasma arc technology for the disposal of municipal solid waste performed by Georgia Tech.  The tests were performed at the lab facilities using both a reactor for ex-situ work and a modified reactor container to simulate in-situ tests.

Test No.

Initial Wt. (kg)

Final Wt. (kg)

Weight Loss (%)

1

16.4

2.7

84

2

13

2.5

81

3 (Note 1)

47.3

19.1

59 (Note 1)

Note 1:  This test consisted of waste with a significant amount of inorganic materials (i.e. soil).  As such, the soil was not readily gasified or otherwise reduced in weight, resulting in a lower percentage weight reduction.

Toxicity Leaching Tests

Standard TCLP tests were performed on vitrified sample materials from Experiment 1.  In all cases, the TCLP results were well below permissible concentration limits established by the EPA.

Heavy
Metal

Allowed Con.
(mg/l)

Measurable
Concentration

Arsenic

5.0

BDL*

Barium

100.00

0.47

Cadmium

1.0

BDL*

Chromium

5.0

BDL*

Lead

5.0

BDL*

Mercury

0.2

BDL*

Selenium

1.0

BDL*

Silver

5.0

BDL*

 

*BDL:  Below Detectable Limits

 

 

Other Viable Commercial By-Products from the Plasma Gasification Process:

  • Vitrified glassy slag:  The ATONN process follows for the recycling of this commodity in either aggregate form (of particular value to the construction / concrete industry) or to be spun into a form of rock wool insulation. 

 

  • Carbon Dioxide:  The ATONN plasma gasification system can be engineered and designed with the ability to produce carbon dioxide for commercial and industrial use.  Our calculations have shown that up to 1,000 lbs of carbon dioxide can be captured from one ton of municipal solid waste.  The advantage of this depends solely on the local prices for CO2 and varies from place to place.  The cost for this extra equipment is not usually included.

 

Additional Processes:

It is of interest that the plasma process can be used for many different processes.  The only thing in common in these processes is that the equipment will not change much, except in the feeders and probably the gas treatment –both of which will be modified to optimize performance. Likewise the by products of the process can have multiple uses. 

  • Syngas can be used for other purposes besides power generation.  It is an excellent raw material for the generation of Methanol.  There is a plant design already done by Hydro-Chem a division of the Pro-Quip Corp. which is itself a subsidiary of Linde AG, one of the world’s largest gas and chemical design and construction companies.   Hydro-Chem also has extensive experience in the generation of Hydrogen.  Their modular plants would interface very nicely with our design.

Syngas can be used to generate hydrocarbon fuels, such as diesel.  The technology is not new.  Germany used coal gasification as a method of generating liquid diesel fuel during WW II.  It also has application in the refinery industry where the hydrogen can be generated from the gasification of the waste petroleum coke and then used to lower the sulphur in fuels.  This is becoming critical based on the new low sulphur fuel requirements.

  • Slag – which in this project is being supplied as fiber for the rockwool market – can also be used as a fibre replacement for the now banned asbestos.  As such, it can be use to manufacture water pipes (the old AC pipes), roofing materials, ceiling tiles, flooring tiles, etc.  The applications are numerous based on the wide spread use of asbestos.  Fortunately, unlike asbestos, the slag fibres are non-hazardous or dangerous.

 

  • Metalsas mentioned earlier, the metals will pool so that they can be collected in their metallic form by casting into ingots or billets.  As the contamination of the metals will be only the contamination that has been included in the feed, in some cases it is possible to recover the metals in very pure forms.  The steel collected from tires will be stainless.  In a different case, if Nickel Cadmium batteries are processed alone, it is possible to collect the Nickel in its metallic form and the Cadmium by precipitating it in the quench.

 

Additional Feedstocks:

 

  • Hazardous waste can be dissociated in a plasma arc system due to its temperature and closed environment. Plasma arc systems can be used for the destruction of chlorinated hydrocarbons that can not be easily processed with other methods.   Items such as PCB (Polychlorinated biphenyls) are another group of chemicals that are also easily dissociated and provide a significant source of syngas.  The main issue of any hazardous waste destruction that is intermixed with MSW is one of obtaining permits, since the molecular dissociation will occur regardless of the feedstock composition.

 

  • Coal Gasification:  The plasma system does not care what it dissociates.  If the energy imparted by the plasma is greater than the energy of the molecular bond, the molecule will dissociate.  As such, it is possible to gasify coal and produce syngas quite readily.  The Sulphur in the coal can be collected as an acid gas or it can be made to react with lime to form a calcium sulphate slag.  Regardless, it is possible to successfully gasify coal with minimum concern to its level of sulphur.

Petrochemical Industry:  Plasma has several applications in the petrochemical industry both in the refinery and the plastic manufacturing sector. 

The refineries generate a petroleum waste product that is a heavy hydrocarbon.  Depending on the process, this is sometimes called petroleum coke.  This material is rich in both Carbon and Hydrogen.  The new low-sulphur fuel regulations are increasing the demand for Hydrogen at the refinery, which is currently being generated from the breakdown of Methane (natural gas).  This hydrogen is becoming more and more expensive as the cost of natural gas continues to increase.  In addition, the disposal of the pet coke can be expensive as some of this product can be considered hazardous or may not be suitable as a fuel because of the high sulphur content and the presence of heavy metals.  None of these problems affect plasma since it dissociates and recovers both the energy from this waste product and generates large amounts of hydrogen as a by product.

 

The second application is in the area of plastic manufacturing. Many plastic plants rely on syngas as the raw material in their manufacturing process.  This syngas currently has to be generated from other sources, most often the aforementioned expensive natural gas.  We have been approached by Polyethylene plants that have specifically requested Carbon Monoxide.

 

Besides those needs, there are applications for the destruction of hazardous waste and for the recovery of metals. 

Equipment, Construction and Engineering

4,000 Tons per day Plasma Waste Conversion Plant

Performa Financial Documentation for a (3,840) 4000 Ton per day Plasma Waste Conversion Plant:

Plant Envelope

Cost:

Including all civil, structural and architectural design and engineering, site preparation storm water management, sediment and erosion control, internal access roadways, security measures, fencing, exterior lighting, all concrete foundations and slabs, paving and curbs, 12,400 square foot main plant facility including electrical, mechanical and plumbing, exhaust fan system, dust and odour control, systematic wash down and disinfection, ancillary building for parts, maintenance and administration, accommodations for 150 employees including restrooms, locker rooms, and management offices, internal communication systems, heavy equipment garage and landscaping.

   18,366,000

Receiving Storage and Processing

 

Including in-ground weigh scale system with scale house and “credit card” reader system including network into main plant administration system, compactor systems in floor hopper style, rear feed, 30 HP power packs, pre-crusher systems with in floor hopper, 30 HP power packs, holding and storage container system, required implant trucks and heavy equipment, overhead crane system, all crane rail moving floor system with hydraulic lift tables.

13,680,000

Reactor Department

 

Compactor/extruders, vertical ram bridge breakers hydraulic tilting platforms, load cell sets, proximity sensors, water cooling tanks with drag conveyor systems for slag aggregate, electrical equipment for electrode reactor including transformers, HDR power systems, rectifiers and control panels, plasma arc reactors, gas exhaust piping, steam injection systems, gas surge tanks, slag tapping assemblies with induction coil heating, metal tapping assemblies with induction coil heating, spare electrodes, open top slag containers, heavy equipment for moving slag and metal, gas analyzer sets, compressors, generators, all required piping, wiring, interface and networking.

158,200,000

Gas Cleaning Operation

 

Scrubber systems for chlorides and sulphides, secondary gas analysis systems after reactor and before exit, all required piping, wiring, interface and networking.

35,400,000

Combined Cycle Electric Generating Department

 

Fire tube boilers, boiler feed water heat exchangers, gas compressors, gas turbines and generators, primary boiler with dual fuel supply, exhaust gas analysis systems equipment, exit stack, all required piping, wiring, interface and networking

138,000,000

Associated Capital Costs

 

Insurance, legal fees, accounting, permitting, technical training, administration subcontracts, security and contingency

37,633,380

Engineering Design and project Management

 

 

25,470,620

 Insurance Coverage

Included

  • ·         TOTAL
  • 426,970,000

 

Assumptions

Capital Cost per 4000 Ton per Day Conversion Plant

$426,970,000.00

Capital cost per reactor

47,441,111.00

Hourly design throughput of MSW per reactor

20 Tons / Hour

Average yearly availability per reactor (1 spare included)

100%

Average hourly throughput per reactor (including downtime)

20 Tons / Hour

Average daily throughput per reactor

480 ton / day

Average Yearly throughput per reactor

175,200 Ton / Year

Number of reactors online (plus 1 spare)`

8

Total average hourly throughput for plant

160 Ton / Hour

Total average daily throughput for plant

3,840 Ton / year

Total average yearly throughput for plant

1,401,600 Ton / Day

Client Guaranteed MSW

3,840 Ton / Day

Heat Content of MSW

4,500 Bt5u/lb

Percent by weight of MSW left as residue (slag)

20% to slag by Wt.

Yearly megawatts available for sale

1,074,676

Tons of CO2 produced per ton of MSW

0.15

Performa Cash Flow Analysis

General Information

Electric rates per megawatt

$51.50

Tipping fee per ton of MSW

$30.00

Tons per year of MSW processed

1,401,600 tons

Net megawatts for sale per year

1,074,676

Sale price for Rockwool Fibre

$175.00 per ton

Sale price for CO2

$95.00 per ton

Yearly Tonnage of Rockwool Fibre produced

280,320 tons

Yearly tonnage of CO2 recovered

210,240 tons

 

Revenue Information

Sale of electricity megawatt

$55,345,814.00

Tipping fees

$42,048,000.00

Sale of Rockwool Fibre produced

$49,056,000.00

Sale of recovered CO2

$19,972,800.00

GROSS Total Revenues

$166,422,610.00

 

Operating Costs

Total plant wages (four shifts)

$4,045,240.00

Total Benefits

$1,415,834.00

 

 

Total Payroll Benefits

$5,461,074.00

Plant Expenses

Electrode / Reactor maintenance

$4,708,000.00

Refractory maintenance

$6,000,000.00

CoGen Equipment, Filter/Scrubber maintenance

$8,475,000.00

Miscellaneous including utilities, fuel, equipment, etc.

$4,902,000.00

Total Plant Expenses

$29,546,074.00

 

Insurance Expenses   

Insurance, legal and accounting

$4,384,000.00

TOTAL OPERATING EXPENSE

$33,930,074.00

 

 

 

 

GROSS REVENUE

$166,422,610.00

NET PROFIT

$132,492,540.00

Pre-recycled Municipal waste: $37.00

Non-recycled Municipal waste: $55.00

Bio-hazardous waste: $1625.00+

Hazardous Petroleum and Chemical Waste: $600.00+

Asbestos etc: $600.00+

Tires, Computer, Refrigerator, Mattress: $125.00+

  1. All the above numbers will change as the facility receives hazardous / bio hazardous wastes and also petroleum waste products since the tipping fees are fluctuating between $55 and $1,250 per metric ton.
  2. In some cases, the tipping fee must be negotiating base on the nature of waste.
  3. All above figures has been used as a guideline only and the final pricing for Tipping fees and Price of electricity will be concluded at the time of signing the final contract and actual pricing will be higher therefore, the actual profit margin shall be higher as well.
  4. Total additional electricity for sale from this system and with Steam Turbine configuration can’t exceed 150 MW per hour. However, with adaptation of the new Turbine Propane Drive systems, the actual power generation can be increased to 500 MWH. There will be an additional cost to manufacture such a Turbine and this additional investment will be around $350,000,000.00.

 

 

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