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New NOX Knockout, Plus Heat Recovery and Emissions Control

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Thermal Energy International, near Ontario Canada, has made even greater progress in the year since the last UFTO note about them (see below).

The company “has received international market patent protection for its revolutionary 90% reduction “Low NOx” FLU-ACE Air Pollution Control and Heat Recovery technology, for application to all natural gas, oil, and coal burning energy process waste exhaust gases.” (from a company press release)

The Low NOx process oxidizes NO into NO2, which can then be absorbed by any wet scrubber. If FLU-ACE is used as the scrubber, the additional benefits of heat recovery and removal of other emissions can also be accomplished.

The Low NOx technology achieves 90% NOx removal at 30% to 50% lower cost per ton removed than the competing (currently accepted) reduction methods (SCR, SNCR). Other advantages are that the Low NOX does not produce hazardous byproducts, does not adversely affect the energy efficiency and operating cost, and does not suffer from an “ammonia slip” concern; which are all documented disadvantages of SCR technology.

The Low NOx process is a simple phosphorus (P) additive atomization and injection into the flue gas; which initially creates Ozone (O3) which then reacts with NO to produce NO2, and then the NO2 is easily 90% removed through a standard wet scrubber, or 98% removed through a FLU-ACE condensing & reactive scrubber.

Adding phosphorus is not a new idea. Years ago, researchers at Lawrence Berkeley Lab worked on putting it into the scrubber slurry (see UFTO Report, June ’95) , but weren’t able to get the performance to make it practical. Thermal Energy’s chief scientist was able to figure out the complex series of chemical reactions and determine that the best way to inject phosphorus was directly into the flue gas, as it leaves the boiler.

Installation is not complex, and can be readily done as a retrofit on almost any kind of exhaust system, with only a moderate degree of site-specific engineering.

To recap–there are two stories here. One is FLU-ACE, and the other is Low NOx. They can be used together or separately.

Low NOx provides significant cost savings over available technology. If a wet scrubber is already in place, costs can be 65-75% less expensive than SCR, at 90% NOx removal. As mentioned earlier, if FLU-ACE is installed as the scrubber, then NOx removal can approach 98%, and provide heat recovery and removal of other pollutants, with costs 30-50% cheaper than SCR alone.

Notably, FLU-ACE can remove multiple emissions at the same time, including fine particulates, hydrocarbons, heavy metals and VOCs, in addition to HCl, SOx, NOx, and CO2. The system replaces the smoke stack, with a smaller foot print and lower height.

It’s also worth noting that FLU-ACE qualifies under Canadian government export support programs that can provide low interest financing and performance guarantees.

The company is seeking to raise $12 Million in debt and equity capital, and has a business plan that they will share with qualified investors or potential partners. (I have a pdf copy of the Plan Summary, which I can forward on request.)

For further information:
Thomas Hinke, President
Thermal Energy International Inc.
Neapean (Ottawa), Ontario, Canada
613-723-6776 Fax: 613-723-7286 E-mail: thermal@istar.ca
Web Site – http://www.thermalenergy.com/

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–previous UFTO NOTE —-
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Subject: UFTO Note – Flue gas heat recovery and air pollution control
Date: Thu, 22 Jan 1998

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Flue gas heat recovery and air pollution control

Simple in concept, FLU-ACE has accomplished something that many others have tried unsuccessfully to do for a long time, and they have plants that have been operating for over 10 years. Their condensing heat exchanger system replaces the stack in combustion systems, recovering almost all of the waste heat, and removing most of the emissions. With modifications, it even can remove up to 50% of the CO2.

It can be thought of as pollution control that pays for itself in fuel savings–or visa versa. Water is sprayed into the hot flue gas, both cooling and cleaning it. The water is then collected, passed through a heat exchanger to recover the heat, and treated to neutralize the acidity and remove contaminants.

Condensing heat exchangers aren’t new, but they normally can be used only when the hot gas is reasonably clean. FLU-ACE can handle any kind of gas, even if it contains particulates, acids and unburned hydrocarbons. Conventional wisdom holds that corrosion, plugging and clogging should defeat this approach, but FLU-ACE has overcome problems with its patented design. Systems show no degradation after years of operation. It has even been qualified for use with biomedical incinerator exhaust.

Industrial boilers and cogeneration plants are ideal applications. The installed base includes district heating systems, sewage treatment plants, hospitals, pulp and paper mills, and university campuses. Heat recovery is even greater when the exhaust gas is high in moisture content, e.g. in paper mills and sewage treatment. The largest system to date is 15 MW thermal, but there is no limit on the size.

A fossil power plant could use about 15% of the recovered heat for makeup water heating, so the economics are better when there are nearby uses for the heat. The company really wants to do a coal burning power plant–a slipstream demo could be the first step.

The company is a small publicly traded Canadian firm (symbol TMG – Alberta Stock Exchange). They have a dormant U.S. subsidiary, and are seeking U.S. partners, joint ventures and alliances for market expansion.

(UFTO first reported on FLU ACE in October ’95)

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The following materials are excerpted from the company’s materials:

The unique FLU-ACE technology is a combined heat recovery and air pollution control system, which recovers up to 90% of the heat normally wasted in hot chimney flue gases. FLU-ACE substantially reduces the emission of “Greenhouse Gases” (including C02), “Acid Gases” (including SOx), Nitrogen Oxides (NOx), unburned hydrocarbons (such as THC and VOCs), and particulates (such as soot and fly ash). It eliminates the need for a conventional tall smoke stack or chimney.

Thermal Energy International Inc. has built eleven FLU-ACE Air Pollution Control and Heat Recovery Systems in Canada. All of Thermal’s FLU-ACE installations in Ontario have been approved by the Ontario Ministry of Environment and Energy. The life expectancy of the FLU-ACE system is at least thirty-five to forty years. In December 1997, the company received patent protection in 42 countries; the US patent is expected early in 1998.

Low NOx FLU-ACE provides a payback on investment and is self financing from the savings that it generates for the industry user. The company is able to provide “Off-Balance” Sheet financing or 3rd party financing options for acquisition of its FLU-ACE technology by industrial and institutional buyers.

Using a direct-contact gas-to-liquid mass transfer and heat exchange concept, the system is designed to process flue gas from combustion of fossil fuels, waste derived fuels, waste, biomass, etc. The FLU-ACE System is configured as a corrosion resistant alloy steel tower at a fraction of the size of any conventional stack. All of the hot flue gas from one source or multiple sources (including co-gen and boilers) are redirected into the FLU-ACE tower, where it is cooled to within one to two degrees of the primary water return temperature, which enters the tower typically at between 16¡C (60¡F) and 32¡C (90¡F) depending on the season and outside air temperature. The heat (both latent and sensible) from the flue gas is transferred to the primary water which then reaches up to 63¡C (145¡F) and with special design up to 85¡C (185¡F), and circulated to various heat users.

FLU-ACE most sophisticated version (HP) reduces air pollutant emissions by over 99% including particulate down to 0.3 micrometers in size, and simultaneously recovers 80-90% of the heat in the flue gas normally exhausted into the atmosphere. This results in a reduction of fuel consumption by the facility up to 50%.
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E-Beam Stack Gas Scrubbing

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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.