# US 7,794,523 B2 · Method for the recovery and re-use of process gases > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,794,523 B2 - Document ID: US7794523B2 - Status: Granted - Kind: B2 - Application number: 11/598,928 - Filed: 2006-11-14 - Published: 2008-05-15 - Granted: 2010-09-14 - Earliest claimed: 2006-11-14 - Assignees: Linde Aktiengesellschaft - Inventors: Walter H. Whitlock - Web page: https://patentgrep.com/patent/US7794523B2 ## CPC - B01D 53/40: Acidic components (B01D53/44 takes precedence) - B01D 53/75: Multi-step processes - F25J 3/028: {separation of noble gases (from air F25J3/04642; in general C01B23/00)} - B01D 53/77: Liquid phase processes - B01D 53/86: Catalytic processes - B01D 2258/0216: from CVD treatment or semi-conductor manufacturing - F25J 2200/02: in a single pressure main column system - F25J 2215/34: Krypton - F25J 2215/36: Xenon - Y10S 55/30: Exhaust treatment - 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) - F25J: LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS {OR LIQUEFIED GASEOUS} MIXTURES BY PRESSURE AND COLD TREATMENT {OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE (cryogenic pumps F04B37/08; gas storage vessels, gas holders F17; filing vessels with, or discharging from vessels, compressed, liquefied or solidified gases F17C; refrigeration machines, plants, or systems F25B)} - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract The present invention relates to methods and systems for processing an exhaust stream containing a recyclable component mixed with other components and impurities to produce a high purity product that contains all of the recyclable component. One or more waste streams containing none of the recyclable component are also produced. The present invention particularly relates to the recovery of valuable recyclable components used in the manufacture of semiconductor devices. ## Claims ### Claim 1 A method for the recovery of process gas, comprising: scrubbing a gas exhaust stream containing the process gas with water in a first scrubber to obtain a first scrubbed stream; scrubbing the first scrubbed stream with a water containing solution in a catalyst bed in a second scrubber to obtain a second scrubbed stream; compressing the second scrubbed stream; drying the second scrubbed stream in a heat exchanger process; filtering the second scrubbed stream to obtain a dry compressed stream; further drying the dry compressed stream to obtain an ultra-dry stream; cooling the ultra-dry stream to obtain a liquid reflux stream enriched in the process gas and a vapor stream depleted in the process gas; distilling the liquid reflux stream to recover a substantially pure process gas. ### Claim 2 (depends on 1) A method according to claim 1, further comprising treating the vapor stream to recover trace amounts of the process gas and a vent stream free of process gas. ### Claim 3 (depends on 1) A method according to claim 1, wherein the process gas is Xe, Kr, CF4, C2F6, SF6, or NH3. ### Claim 4 (depends on 1) A method according to claim 1, wherein the water containing solution is KOH, NaOH or H2O2. ### Claim 5 (depends on 1) A method according to claim 1, wherein the catalyst bed is an activated carbon catalyst bed or a hydrophilic activated carbon catalyst bed. ### Claim 6 (depends on 1) A method according to claim 1, wherein further drying comprises drying in a membrane dryer. ### Claim 7 (depends on 6) A method according to claim 6, wherein a portion of the dry compressed stream is used as a purge gas for the membrane dryer. ### Claim 8 (depends on 7) A method according to claim 7, further comprising returning the dry compressed stream used as a purge gas to the first scrubber. ### Claim 9 (depends on 1) A method according to claim 1, wherein further drying comprises a pressure swing adsorption process using an adsorbent. ### Claim 10 (depends on 1) A method according to claim 1, cooling the ultra-dry stream comprising cooling to a temperature less than 16 degrees above the freezing temperature of the process gas. ### Claim 11 (depends on 10) A method according to claim 10, wherein the temperature is less than 3 degrees above the freezing temperature of the process gas. ### Claim 12 (depends on 1) A method according to claim 1, wherein distilling comprises stripping high volatility impurities from the liquid reflux stream to obtain a substantially pure liquid reflux stream and further comprising vaporizing the substantially pure liquid reflux steam to obtain the substantially pure process gas. ### Claim 13 (depends on 1) A method according to claim 1, wherein distilling comprises removing high volatility impurities in a first distillation column and removing low volatility impurities in a second distillation column. ### Claim 14 (depends on 1) A method according to claim 1, further comprising treating the vapor steam to separate any trace amounts of process gas. ### Claim 15 (depends on 14) A method according to claim 14, wherein treating comprises a pressure swing adsorption process or a molecular sieve. ### Claim 16 (depends on 1) A method according to claim 1, wherein the gas exhaust stream comes from a semiconductor process.