# US 4,399,041 A · Process for particulate removal from coal liquids > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,399,041 A - Document ID: US4399041A - Status: Granted - Kind: A - Application number: 06/267,141 - Filed: 1981-05-26 - Granted: 1983-08-16 - Earliest claimed: 1981-05-26 - Assignees: International Coal Refining Company - Inventors: Gerald C. Rappe - Web page: https://patentgrep.com/patent/US4399041A ## CPC - C10G 32/02: by electric or magnetic means - B01D 21/0012: {Settling tanks making use of filters, e.g. by floating layers of particulate material} - B01D 21/26: Separation of sediment aided by centrifugal force {or centripetal force}(centrifuges B04B; cyclones B04C) - B01D 21/267: {by using a cyclone} - B01D 35/06: Filters making use of electricity or magnetism (ultrafiltration, microfiltration B01D61/14; electrodialysis, electro-osmosis B01D61/42; devices comprising filters and magnetic separators B03C1/30) - B03B 9/005: {specially adapted for coal} - B03C 5/024: {using high-gradient differential dielectric separation, i.e. using a dielectric matrix polarised by an external field} - B04C 5/26: for series flow - B04C 9/00: Combinations with other devices, e.g. fans, {expansion chambers, diffusors, water locks}(with filters B01D50/00) - C10G 1/045: {Separation of insoluble materials} - C10G 31/10: with the aid of centrifugal force - B04C 2009/002: {with external filters} - C10G: CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION (cracking to hydrogen or synthesis gas C01B; cracking or pyrolysis of hydrocarbon gases to individual hydrocarbons or mixtures thereof of definite or specified constitution C07C; cracking to cokes C10B); RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES - 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) - B03B: SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS - B03C: MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS (separating isotopes B01D59/00; combinations of magnetic or electrostatic separation with separation of solids by other means B03B, B07B) - B04C: APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES ({centrifugal separation of water from steam B01D45/12;} jet mills B02C19/06; {wind sifters B07B7/00;} cyclonic type combustion apparatus F23; {vortex burners for cyclone-type combustion apparatus F23D1/02; cyclonic type combustion apparatus for gas turbines F23R3/00}) ## Abstract Suspended solid particulates are removed from liquefied coal products by first subjecting such products to hydroclone action for removal in the underflow of the larger size particulates, and then subjecting the overflow from said hydroclone action, comprising the residual finer particulates, to an electrostatic field in an electrofilter wherein such finer particulates are deposited in the bed of beads of dielectric material on said filter. The beads are periodically cleaned by backwashing to remove the accumulated solids. ## Claims ### Claim 1 The method of removing suspended solid particulates contained in a liquefied coal product which consists essentially of the steps of: (a) subjecting said liquefied coal product as feed to a hydroclone treatment, thereby separating the said to obtain an under flow portion of substantially higher solids concentration than that of said feed and an overflow portion of lower solids concentration than that of said feed; said overflow portion containing at least the major part of the particles from said feed of the size range up to about 10 microns; (b) introducing said overflow portion into the electrostatic field of an electrofilter to deposit contained solids in said filter; and (c) discharging the solids-free liquid filtrate from said electrofilter. ### Claim 2 (depends on 1) The method as defined in claim 1 including the step of periodically regenerating said electrofilter by backwashing with a liquid stream to remove deposited solids therefrom, the supply of electrical energy to said filter being discontinued during said backwashing step. ### Claim 3 (depends on 2) The method as defined in claim 2 wherein said backwashing liquid is a coal derived solvent with a boiling point range from about 300.degree. F. to about 850.degree. F. ### Claim 4 (depends on 1) The method as defined in claim 1 wherein at least a portion of said liquefied coal product has a boiling point greater than 850.degree. F. ### Claim 5 (depends on 1) The method as defined in claim 1 wherein said hydroclone treatment is carried out in two stages and wherein the underflow from said first stage is charged to said second stage; and the overflow from said second stage is combined with the overflow from said first stage, these combined overflow portions being charged to the electrostatic field of the electrofilter. ### Claim 6 (depends on 1) The method as defined in claim 1 wherein said hydroclone treatment is carried out in two stages and wherein the underflow from said first stage is charged to said second stage; the overflow from said second stage being recycled to the feed of said first stage and the overflow from said first stage being charged to the electrostatic field of the electrofilter. ### Claim 7 (depends on 4) The method as defined in claim 4 wherein said feed is introduced to the hydroclone treatment at a temperature such that the viscosity of the feed does not exceed 5 cp. ### Claim 8 (depends on 4) The method as defined in claim 4 wherein said feed is introduced to the hydroclone treatment at a temperature such that the viscosity of the feed does not exceed 1 cp. ### Claim 9 (depends on 4) The method as defined in claim 4 wherein the overflow product from the hydroclone treatment charged to electrofiltration is at a temperature sufficiently high to have a viscosity below 10 cp and such that the liquid resistivity exceeds 10.sup.8 ohms-cm. ### Claim 10 (depends on 4) The method as defined in claim 4 wherein said liquefied coal slurry is one obtained from a process for the solvent refining of coal. ### Claim 11 (depends on 4) The method as defined in claim 4 wherein said liquefied coal product has a mass median particle size of about 7 microns, a solids density of about 2 grams per cubic centimeter and a liquid density of about 0.9 grams per cubic centimeter; said product being charged to the hydroclone treatment at a temperature of about 500.degree. F. and at a pressure of 200 psi.