# US 2013/0153404 A1 · Catalyst-Free Removal of NOx from Combustion Exhausts Using Intense Pulsed Electron Beams > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0153404 A1 - Document ID: US20130153404A1 - Status: Published application - Kind: A1 - Application number: 13/645,556 - Filed: 2012-10-05 - Published: 2013-06-20 - Earliest claimed: 2011-12-15 - Assignees: The United States of America as represented by the Secretary of the Navy - Inventors: John D. Sethian; Matthew Myers; Mathew Wolford; Frank Hegeler - Web page: https://patentgrep.com/patent/US20130153404A1 ## CPC - B01J 19/085: {Electron beams only} - B01D 53/32: by electrical effects other than those provided for in group B01D61/00 - B01D 53/74: General processes for purification of waste gases; Apparatus or devices specially adapted therefor (B01D53/92 takes precedence) - B01D 2257/404: Nitrogen oxides other than dinitrogen oxide - B01D 2259/812: Electrons - B01J 2219/0875: Gas - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract A process and apparatus for removing NOx from exhaust gases produced by combustion-based energy sources. An array of high voltage pulsed electron beams are repetitively generated and transported through a thin foil into the exhaust gas containing NOx. The electron beam deposits its energy into the gas and produces reactive radicals N2+, N+, e, N2 from the NOx in the gas. These radicals recombine through chemical reactions to produce benign by-products nitrogen N2 and oxygen O2 which are output into the atmosphere. ## Claims ### Claim 1 A process for catalyst-free removal of NOx from combustion exhaust, comprising: irradiating a combustion exhaust gas containing NOx with an electron beam as the exhaust gas travels through a reaction chamber, the exhaust gas being free from ammonia or any other added catalyst, energy from the electron beam causing the NOx to dissociate into reactive radicals N2+, N+, e, and N2; the radicals combining to form neutral nitrogen N by the reactions N2*→2N, N2++e→2N and N++e→N, and the neutral nitrogen N combining with oxygen 0 and nitric acid NO from the NOx to form to form nitrogen and oxygen in a three-body reaction N+NO→N2+O and O→O2, the reactions proceeding without any catalyst; wherein the electron beam is a pulsed electron beam that is turned on to cause the NOx to dissociate into the reactive radicals, is turned off during the formation of the neutral N from the reactive radicals, and remains off during the formation of the nitrogen N2 and oxygen O2. ### Claim 2 (depends on 1) The process according to claim 1, wherein the pulsed electron beam is turned on for about 140 to about 300 ns and turned off for about 50 to about 200 msec, with a repetition rate of about 5 to about 20 pulses per second. ### Claim 3 (depends on 1) The process according to claim 1, wherein the pulsed electron beam has a voltage of about 500,000 to about 1,000,000 Volts. ### Claim 4 (depends on 1) The process according to claim 1, wherein the pulsed electron beam provides a current of about 100,000 to about 500,000 Amperes to the exhaust gas. ### Claim 5 An apparatus for the catalyst-free removal of NOx from combustion exhausts, comprising: an electron beam source configured to irradiate a combustion exhaust containing NOx with a plurality of pulsed electron beams as it travels through a reaction chamber, the exhaust gas being free from ammonia or any other catalyst as it travels through the reaction chamber, energy from the electron beams causing the NOx to dissociate into reactive radicals N2+, N+, e, and N2, the radicals combining to form neutral nitrogen N by the reactions N2*→2N, N2++e→2N and N++e→N, and the neutral nitrogen N combining with oxygen O and nitric acid NO from the NOx to form to form nitrogen and oxygen in a three-body reaction N+NO→N2+O and O→O2, the reactions proceeding without any catalyst; wherein the electron beam source is configured to turn the electron beam on to cause the NOx to dissociate into the reactive radicals, and to turn the electron beam off during the formation of the neutral N from the reactive radicals and during the formation of the nitrogen N2 and oxygen O2. ### Claim 6 (depends on 5) The apparatus according to claim 5, wherein electron beam source comprises a high voltage pulsed power supply configured to apply a high voltage to a cathode to produce the electron beam. ### Claim 7 (depends on 6) The apparatus according to claim 6, wherein the high voltage pulsed power supply comprises a Marx Generator. ### Claim 8 (depends on 7) The apparatus according to claim 7, wherein the Marx Generator is made from solid-state thyristors and thin film capacitors, a saturable magnetic inductor output switch, and at least one pulse forming line. ### Claim 9 (depends on 6) The apparatus according to claim 6, wherein the cathode comprises a large area cathode having a width of about 20 to 60 cm and a length of about 100 to 200 cm. ### Claim 10 (depends on 6) The apparatus according to claim 6, wherein the cathode comprises an array of straight carbon or polymer fibers bonded to a conducting base, the fibers having a length of about 2 to about 6 mm. ### Claim 11 (depends on 6) The apparatus according to claim 6, wherein the cathode is configured to produce the electron beam by one of field emission and plasma formation. ### Claim 12 (depends on 5) The apparatus according to claim 5, wherein the electron beam is accelerated into the exhaust gas through a thin metal foil as the exhaust gas travels into the reaction chamber. ### Claim 13 (depends on 12) The apparatus according to claim 12, wherein the thin metal foil comprises stainless steel, titanium, or a titanium alloy. ### Claim 14 (depends on 12) The apparatus according to claim 12, wherein the thin metal foil has a thin coating to prevent a chemical interaction between the metal foil and the exhaust gas. ### Claim 15 (depends on 5) The apparatus according to claim 5, comprising a plurality of electron beam sources arranged around the reaction chamber and being configured to simultaneously apply the pulsed electron beam to the exhaust gas as it travels through the reaction chamber. ### Claim 16 (depends on 5) The apparatus according to claim 5, wherein the pulsed electron beam is configured to be turned on for about 140 to about 300 ns and turned off for about 50 to about 200 msec, with a repetition rate of about 5 to about 20 pulses per second. ### Claim 17 (depends on 5) The apparatus according to claim 5, wherein the pulsed electron beam is configured to have a voltage of about 500,000 to about 1,000,000 Volts. ### Claim 18 (depends on 5) The apparatus according to claim 5, wherein the pulsed electron beam is configured to provide a current of about 100,000 to about 500,000 Amperes. ### Claim 19 (depends on 5) The apparatus according to claim 5, wherein the electron beam energy is deposited into the combustion exhaust.