# US 2014/0193924 A1 · Instruments for monitoring electrostatic phenomena in reactors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0193924 A1 - Document ID: US20140193924A1 - Status: Published application - Kind: A1 - Application number: 14/142,179 - Filed: 2013-12-27 - Published: 2014-07-10 - Earliest claimed: 2012-12-28 - Assignees: ExxonMobil Research and Engineering Company - Inventors: William Anthony Lamberti; Joseph Andres Moebus; Harry William Deckman; Charles R. Buhler; Judson S. Clements - Web page: https://patentgrep.com/patent/US20140193924A1 ## CPC - G01N 27/60: by investigating electrostatic variables {, e.g. electrographic flaw testing (G01N27/007 takes precedence)} - C08F 2/002: {Scale prevention in a polymerisation reactor or its auxiliary parts} - C08F 2/34: Polymerisation in gaseous state - C08F 2400/02: Control or adjustment of polymerization parameters - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS ## Abstract Probes for monitoring electrostatic phenomena in challenging environments, such as fluidized bed reactors. These probes include a coated or uncoated static probe for measuring electric field and or particle charge state, an oscillatory electric field probe for measuring electric field, a chopped electric field probe for measuring electric field, and a radio-frequency antenna probe for detecting electrostatic discharges. ## Claims ### Claim 1 A coated static probe which monitors the electrostatic charge on particles entrained in the gas stream of a vessel, said probe comprising: an electrode with a modified surface comprising an electrically insulating coating, thereby mitigating triboelectrification of said probe arising from charge transfer from impinging particulates and extraneous signals via charge saturation of said coating. ### Claim 2 (depends on 1) The probe according to claim 1, wherein said coating is a dielectric material that maintains a saturation charge layer and inhibits tribocharging. ### Claim 3 (depends on 2) The probe according to claim 2, wherein said dielectric material is a high dielectric strength, and high volume resistivity. ### Claim 4 (depends on 2) The probe according to claim 2, wherein said dielectric material is at least one material selected from the group consisting of: polyethylene, polypropylene, polytetrafluoroethylene, polyether ether ketone, aluminum oxide, silicon dioxide, iron oxide, and any other electrically insulating material. ### Claim 5 (depends on 2) The probe according to claim 2, wherein said dielectric material maintains said charge saturation by exhibiting at least one property selected from the group consisting of: dielectric strength, surface and volume resistivity, and placement within triboelectric series. ### Claim 6 (depends on 5) The probe according to claim 5, wherein said dielectric strength determines the maximum electric field at which the material reaches electrical breakdown. ### Claim 7 (depends on 5) The probe according to claim 5, wherein said surface and volume resistivity determines the rate at which a material will discharge analogous to an RC circuit. ### Claim 8 (depends on 5) The probe according to claim 5, wherein said placement within triboelectric series affects the amount and polarity of charge transferred due to contact and separation. ### Claim 9 (depends on 1) The probe according to claim 1, wherein said coating is applied to said static probe by dip coating. ### Claim 10 (depends on 9) The probe according to claim 9, wherein said dip coating comprises the steps of: heating said static probe; submerging said heated static probe into a bed of polymer particles with suitable melting point and adhesive properties, such that said polymer particles adhere to said static probe; heating said static probe after said polymer particles have been adhered thereto to the point where they begin to flow; and once said polymer particles have formed a uniform coating on said static probe, heating is stopped, thereby allowing said coating to harden on said static probe. ### Claim 11 (depends on 1) A method for monitoring the electrostatic charge on particles entrained in the gas stream of a vessel comprises: disposing said coated static probe according to claim 1 within said gas stream of said vessel. ### Claim 12 (depends on 11) The method according to claim 11, wherein said gas stream is at least one stream selected from the group consisting of: a product discharge stream, a recycle stream, a fluidizing gas stream, a mixing stream, a purge stream, a feed stream, and a transfer stream. ### Claim 13 (depends on 11) The method according to claim 11, wherein said vessel is at least one vessel selected from the group consisting of: a fluidized bed reactor, a product tank, a purge vessel, a holding vessel, a shipping vessel, a discharge tank, a mixing vessel, piping between said vessels, a shipping vessel, a rail car, and a truck. ### Claim 14 A coated static probe which monitors the electrostatic charge on particles entrained in the gas stream of a vessel, said probe comprising: an electrode with a modified surface comprising a coating which measures the ambient direct current electric field by periodically blocking the field near said probe while also substantially preventing particle-to-surface interactions via purging of a sensing element with a flowing gas. ### Claim 15 An RF probe which monitors electrostatic discharges in a vessel, said probe comprising: an antenna; a flange bolted to a mating flange welded on the outside of a wall of said vessel; an electrode connected to said antenna, wherein said rod is hermetically sealed by means of an insulating material, thereby electrically isolating said antenna from said flange; an electronics module and a power supply disposed within a pressure containment housing or a separate shielded, cooled external enclosure located outside of said vessel and electronically connected to said rod; and an electrically conductive wire which electronically connects said antenna to said electronics module. ### Claim 16 (depends on 15) The RF probe according to claim 15, further comprises a double pressure containment housing. ### Claim 17 (depends on 15) The RF probe according to claim 15, wherein said probe is a hardened probe comprising: (a) spark detection electronics, or (b) circuitry with high sensitivity and high speed electrical together with a single channel analyzer and/or frequency based filter circuitry. ### Claim 18 (depends on 17) The RF probe according to claim 17, wherein said frequency based filter circuitry is at least one selected from the group consisting of: lock-in amplification, Fourier analysis, digital filtering and correlation methods. ### Claim 19 (depends on 15) The RF probe according to claim 15, wherein probe sensitivity is proportional to the length of said antenna. ### Claim 20 (depends on 15) The RF probe according to claim 15, wherein said wire is a coax cable and said electronics module comprises a receiver/amplifier filter. ### Claim 21 (depends on 15) A method for monitoring the electrostatic discharges in a vessel comprises: disposing said RF probe according to claim 15 within said vessel. ### Claim 22 (depends on 21) The method according to claim 21, wherein said gas stream is at least one stream selected from the group consisting of: a product discharge stream, a recycle stream, a fluidizing gas stream, a mixing stream, a purge stream, a feed stream, and a transfer stream. ### Claim 23 (depends on 21) The method according to claim 21, wherein said vessel is at least one vessel selected from the group consisting of: a fluidized bed reactor, a product tank, a purge vessel, a holding vessel, a shipping vessel, a discharge tank, a mixing vessel, piping between said vessels, a shipping vessel, a rail car, and a truck. ### Claim 24 A probe which monitors the electrostatic state in a vessel, said probe is at least one selected from the group consisting of: a coated or uncoated static probe, an oscillatory electric field probe, a chopped electric field probed, and a radio-frequency antenna probe. ### Claim 25 A fluidized bed reactor comprising either a coated static probe or a radio frequency (RF) probe disposed in at least one portion of the fluidized bed reactor selected from the group consisting of: a recycle line, product discharge system, fluid bed, expanded or disengagement zone above the fluidized bed, purge system, and product handling or shipping system. ### Claim 26 A stirred, slurry or other type of reactor system with a coated static probe or a radio frequency (RF) probe disposed in said reactor system.