This might be titled, “Son of Ebara”, for those of you familiar with the history. It appears that dramatically better performance may be possible.

This text was provided to me by a private development group with access and connections to the new e-beam technology that is mentioned. I’ve edited the letter to remove some of the proprietary details. Even so, important ideas are disclosed. I would ask that you be especially careful not share it with anyone outside your company (as with all UFTO materials). If you’re seriously interested in pursuing this, I will put you in touch with the sources.

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Below, please, find a short overview of both old and new developments in e-beam processing of industrial exhaust gases.

E-Beam Processing of Industrial Exhaust Gases

— Background
In the past few years new methods of decomposition of VOCs as well as inorganic compounds in flue gases have been developed, primarily involving low-temperature, non-equilibrium plasmas used to selectively decompose organic molecules. The high concentration of electrons, ions, excited species and radicals make these plasmas well suited for driving decomposition reactions that otherwise could be initiated only at very high gas temperature.

Such plasma methods are of particular interest in the decomposition of dilute concentrations of halogenated organic compounds in carrier gas streams such as dry or wet (about 10% relative humidity) air. This type of gaseous waste stream is encountered for example in vapor extraction from soil, air stripping from contaminated water and air pollution control.

Low temperature, non-equilibrium plasmas can be generated by electron beams. They operate at atmospheric pressure in large volumes and in a highly controllable fashion making very high throughput possible. It has been also demonstrated that electron beam becomes even more efficient in decomposition of certain VOCs when combined with certain type of electrical discharge.
Advantages of e-beam induced decomposition over thermal processes become even more pronounced at dilute concentrations of VOCs in the exhaust gases. Because of the high non-equilibrium level of ionization and the selectivity of plasma-chemical decomposition processes the energy required for a given decomposition of dilute concentrations of “electron hungry” VOCs can be 10 to 100 times less than in thermal processes such as incineration, where energy is channeled to all molecules in the gaseous waste stream.

— The EBARA Experience
The Electron Beam Dry Scrubbing (EBDS) process has been first proposed as an efficient method for the simultaneous removal of SO2 and NOx from industrial flue gas in early 1970s. In this process, the e-beam energy generates high concentration of oxidants (OH, HO2, O3) converting SO2 and NOx to nitric and sulfuric acid which in turn form solid powder of ammonium nitrate and sulfate in the presence of added ammonia (NH3).

The Japan Atomic Energy Research Institute and the University of Tokyo have carried out the first research on EBDS in 1970. Follow up technical development by EBARA Corporation lead to the first 10,000 Nm3/hr pilot plant built for a sintering plant at Yahata Works Nippon Steel Corp in 1977. At this plant a flue gas at temperatures T=70-90 C containing 200 ppm of SO2 and 180 ppm of NOx has been treated by 2 x 750keV/45kW e-beam accelerators.

In the US the first and only EBARA-process demonstration unit with a maximum flow rate of 30,000 Nm3/hr has been put in operation in June 1985 at a coal fired power plant in Indianapolis, Indiana. At this plant 2 x 800 keV/80kW electron accelerators has been employed treating 1,000 ppm of SO2 and 400 ppm of NOx in a flue gas at temperatures T=66-150 C.

In December 1985 a 20,000 Nm3/hr pilot plant has been built at Badenwerk, Karlsruhe, FRG at 550 MW coal fired facility employing two 300KeV/90 kW accelerators to treat 50-500 ppm of SO2 and 300-500 ppm of NOx in 70-100 C exhaust gas. In early 1990s similar e-beam treatment pilot units have been built in China, Poland and Russia.

One of the main limitations of EBARA process has been a considerable energy requirement for oxidation of SO2/NOx in an air stream, which amounts in average to about 10 eV/molecule. For a coal fired 300 MW electrical power plant this translates to 12 MW (4% of the electrical power generated by the plant required e-beam power. Back in 1980s the most powerful accelerators were below 100 kW, so 12 MW installation would require 120 x100 kW accelerators and the total accelerator costs in the access of $180 mln. were prohibiting.

— What’s New
A new generation of powerful accelerators manufactured in Russia which can deliver 1MW of e-beam power for the cost of about $1.5 million per unit, can already reduce cost of EBARA process by order of magnitude.

Moreover, a synergetic approach combining electrical discharge and electron beam may allow another tenfold decrease in flue gas processing cost. This is done by essentially substituting much less expensive power of corona discharge for most of the expensive e-beam power. This process maintains all the advantages of e-beam processing such as stability of operation and uniform treatment of large volumes and high mass flows of flue gas — for a fraction of cost compare with e-beam treatment alone. Note that corona discharge alone, without e-beam stimulating effect, suffers from intrinsic non-uniformities and instabilities which greatly reduce its efficiency for industrial scale applications.

Experiments on SO2 oxidation in e-beam stimulated corona discharge have been conducted. We were investigating the plasma chemical processes in an electron beam driven plasma reactor for efficient decomposition of SO2 , NOx or any VOC in carrier gases at atmospheric pressures.

The reactor used an electron beam to stimulate corona discharge at sub-breakdown pulsed electric field. A combination of e-beam and superimposed electrical field in the form of stimulated corona discharge creates plasma with highly controllable electron density and temperature and therefore highly controllable chemical reaction rates.

Synergetic effect of SO2 decomposition by the combined action of e-beam and corona discharge was estimated by the coefficient K equal to the ratio of the discharge energy Wc, consumed from high-voltage source, to the energy Wb deposited by electron beam within the volume of the discharge:
K = Wc / Wb

It has been demonstrated that under certain experimental conditions the energy of discharge consumed from high-voltage source can exceed e-beam energy input by more than 300 times. In other words, a low cost high-voltage rectifier instead of a high-cost electron accelerator provided about 99.7% of the flue gas ionization energy. As a result the same SO2 decomposition effect in e-beam stimulated corona discharge can be achieved with 300 times lower e-beam power compare with irradiation by e-beam alone.

There some indications that shorter e-beam pulses and higher discharge threshold voltage Umax may also lead to the significant decrease of energy cost per oxidation of one SO2 molecule from a typical value of 10 eV/mol down to 3 or even 1eV/mol. However, even at the lower Umax values rather efficient SO2 oxidation process is taking place.

The main purpose of these initial experiments on SO2 oxidation was to demonstrate significance of synergetic effect in e-beam stimulated corona discharge. Discovered synergetic effect allows efficient SO2 decomposition under the conditions when only 0.3% of the total ionization energy is provided by an electron beam with the rest coming from a low cost electrical discharge. Further experiments are necessary to determine the optimum conditions for most efficient decomposition of SO2./NOx mixtures, as well as VOCs in industrial exhaust gases.

We are open to any form of collaboration with a US utility company or research organization, which would enable us to continue these very promising experiments.

I look forward to your comments and suggestions.