# US 2021/0340469 A1 · Method to remove explosive and toxic gases and clean metal surfaces in hydrocarbon equipment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0340469 A1 - Document ID: US20210340469A1 - Status: Published application - Kind: A1 - Application number: 16/951,444 - Filed: 2020-11-18 - Published: 2021-11-04 - Earliest claimed: 2020-04-30 - Assignees: Praxair Technology, Inc. - Inventors: Ashley Zachariah; Richard M. Kelly; Michael St. James; Joseph E. Gulayets - Web page: https://patentgrep.com/patent/US20210340469A1 ## CPC - B08B 3/003: {Cleaning involving contact with foam} - B08B 9/0327: {the fluid being in the form of a mist} - B08B 3/08: the liquid having chemical or dissolving effect - B08B 9/0328: {by purging the pipe with a gas or a mixture of gas and liquid} - B08B 9/08: Cleaning containers, e.g. tanks - C11D 3/0094: {High foaming compositions} - C11D 3/185: {cyclic} - C11D 3/2093: {Esters; Carbonates} - C11D 3/30: Amines; Substituted amines {; Quaternized amines} - C11D 2111/20: Industrial or commercial equipment, e.g. reactors, tubes or engines - B08B: CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL - C11D: DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL ## Abstract The present invention relates to a method of rapidly decontaminating and making safe for entry, hydrocarbon contaminated equipment by sequencing a cleaning mist or foam, an encapsulating mist or foam and a dry carrier gas. ## Claims ### Claim 1 A method for removing hydrocarbon contaminants and toxic gases from a system, comprising the steps of: (i) providing a dry carrier gas source; (ii) providing an encapsulating agent source; (iii) providing a surfactant source (iv) providing a cleaning agent with a high solubility index from a cleaning agent source; (iv) mixing the cleaning agent and the dry carrier gas in a high shear mixing device to create a liquid mist/foam which is introduced into the system so as to solubilize the heavy organic residues on metal surfaces; (v) mixing the encapsulating agent and the dry carrier gas in a high shear mixing device to create a liquid mist/foam which is introduced into the system to cap generation of toxic gases from remaining organic residue; (vi) delivering dry carrier gas from the dry carrier gas source to the system to remove all liquid and gaseous hydrocarbon contaminants out of said system (viii) sequencing or cycling of at least two of the following steps (iv), (v) and (vi) until concentration of explosive gases (LEL's) reaches acceptable limits. ### Claim 2 A method for removing hydrocarbon contaminants and toxic gases from a system, comprising the steps of: (i) providing a dry carrier gas source; (ii) providing an encapsulating agent source; (iii) providing a surfactant source; (iv) mixing the encapsulating agent and the dry carrier gas in a high shear mixing device to create a liquid mist/foam which is introduced into the process system to cap generation of toxic gases from remaining organic residue; (v) delivering dry carrier gas from the dry carrier gas source to the system to remove all liquid and gaseous hydrocarbon contaminants out of said process equipment (vi) sequencing or cycling of steps (iv) and (v) until concentration of explosive gases (LEL's) reach acceptable limits. ### Claim 3 A method for removing hydrocarbon contaminants and toxic gases from a process system, comprising the steps of: (i) providing a dry carrier gas source; (ii) providing a surfactant source; (iii) providing a cleaning agent with a high solubility index from a cleaning agent source; (iv) mixing the cleaning agent and the dry carrier gas in a high shear mixing device to create a liquid mist which is introduced into the process system so as to solubilize the heavy organic residues on metal surfaces; (v) delivering dry carrier gas from the dry carrier gas source to the process equipment to remove all liquid and gaseous hydrocarbon contaminants out of said process equipment (vi) sequencing or cycling of steps (iv) and (v) until concentration of explosive gases (LEL's) reach acceptable limits. ### Claim 4 (depends on 1) The method of claim 1, further comprising: providing the carrier gas at a flow rate ranging from 10 scfm to 10,000 scfm, and wherein said carrier gas is nitrogen. ### Claim 5 (depends on 1) The method of claim 1, wherein the carrier gas is selected from the group consisting of carbon dioxide or a hydrocarbon gas selected from the group consisting of methane, fuel gas, natural gas, ethane, propane, butane and a combination thereof. ### Claim 6 (depends on 1) The method of claim 1, wherein the encapsulating agent comprises a foaming agent and a cleaning a surfactant. ### Claim 7 (depends on 4) The method of claim 4, wherein the encapsulating agent further comprises an amine compound, a methyl ester and a foaming agent. ### Claim 8 (depends on 1) The method of claim 1, wherein the mixing nozzle is an eductor. ### Claim 9 (depends on 1) The method of claim 1, wherein the mixing nozzle is a t-fitting. ### Claim 10 (depends on 1) The method of claim 1, wherein the pressure differential across the mixing device is in the range of 60-150 psig. ### Claim 11 (depends on 1) The method of claim 1, wherein the expansion ratio across the mixing device has a foaming expansion ratio in the range of 200-1000. ### Claim 12 (depends on 1) The method of claim 1, where the LEL is reduced to a lower explosive limit of less than 10 percent. ### Claim 13 (depends on 1) The method of claim 1, where the H2S concentration is reduced to less than 2 ppm. ### Claim 14 (depends on 1) The method of claim 1, wherein the cleaning agent is selected from the group consisting of terpene, naphtha, distillates, xylene, toluene, turpentine, paint thinner, and methyl ester. ### Claim 15 (depends on 1) The method of claim 1, wherein the cleaning agent is injected into the process equipment at a temperature range of 60-250° F. ### Claim 16 (depends on 1) The method of claim 1, wherein the cleaning agent is d-limonene. ### Claim 17 (depends on 1) The method of claim 1, wherein the cleaning agent is an organic hydrocarbon compound with a carbon number in the range of C8-C40.