Precoating panel bed for filtering aerosol of micron-size particulates

Claim 1

The method of treating a gas including the separation and removal of micron-size particulate matter by means of a filter of granular material which comprises: a. arranging granular material smaller than about 40 mesh in a panel bed having a plurality of transversely disposed upwardly spaced gas entry portions separated by interposed supporting members having outer and inner edges with respect to the bed wherein said gas entry portions have gas entry faces substantially contiguous with said outer edges and wherein said bed has gas exit portions spaced from said inner edges; b. forwardly flowing gas through the gas entry portions of the granular material bed and outwardly from the gas exit portions while adding to said gas a first increment of a element selected from the group consisting of granular of fibrous medium substantially smaller than about 120 mesh to separate and accumulate said medium in surface layer deposits at said gas entry faces wherein said gas enters said gas entry faces at a velocity greater than about 16 feet per minute during at least a part of this step (b); c. stopping the forward flow of said gas of step (b); d. causing a transient flow of gas to move in the direction in reverse to the flow of said gas in (b); e. said transient reverse flow producing first a rise at a given rate of rise and subsequently a fall in the pressure difference between said gas exit portions and said gas entry portions, said difference remaining greater than a first critical minimum difference for a time interval less than about 50 milliseconds, said first critical difference being that difference at which a steady flow of gas in said reverse direction just produces a localized spill of said granular material from said gas entry faces, and said difference produced by said transient reverse flow peaking to a top value beyond a second critical minimum difference, which is the pressure difference at which a transient flow of gas in said reverse direction producing said pressure difference at said rate of rise just initiates a body movement of said granular material toward said gas entry faces to spill a portion of the granular material and substantially all of said accumulated granular or fibrous medium and said accumulated micron-size particulate matter from the bed; f. supplying fresh granular material to replace material spilled from said gas entry portions; g. repeating the cycle of said steps (b), (c), (d), (e) and (f) at least two times; h. forwardly flowing gas through the gas entry portions of the granular material bed and outwardly from the gas exit portions while adding to said gas a first increment of said granular or fibrous medium at a rate of addition leSs than about 5 grams per cubic meter of said gas to separate and accumulate said medium in surface layer deposits at said gas entry faces wherein said gas first enters said gas entry faces at a first velocity greater than about 16 feet per minute until the pressure drop across said surface layer deposits reaches about 0.05 centimeters of water per foot per minute of said first velocity and then adding to said gas a second increment of said medium at a rate of addition less than about 5 grams per cubic meter of said gas while the gas enters said gas entry faces at a second velocity greater than about 16 feet per minute until said pressure drop increases by at least about 0.1 centimeters of water per foot per minute of said second velocity and wherein subsequently the rate of flow of said gas is reduced so that the gas enters said gas entry faces at a third velocity less than about one-half of said first velocity and of said second velocity and also less than about 16 feet per minute while adding to said gas at a rate of addition less than about 5 grams per cubic meter of said gas a third increment of said medium wherein said third increment is at least about 1.5 times as large as said second increment when said pressure drop increased with the addition of said second increment by about 0.1 centimeters of water per foot per minute and wherein, when said pressure drop increased by a substantially greater amount, said third increment is at least about 1.5 times as large as the pro rata portion of said second increment that was responsible for an increase of exactly 0.1 centimeter of water per foot per minute; i. stopping the forward flow of said gas of step (h) and forwardly flowing gas to be treated at a rate to enter said gas entry faces at a velocity not substantially greater than said third velocity and thereby treating said gas by contact with said surface layer deposits and thereby to separate and accumulate said micron-size particulate matter on said surface layer deposits of said granular or fibrous medium; j. stopping the forward flow of said gas of step (i); and k. repeating steps (d), (e), (f), (h), (i) and (j) in a cyclic manner.

Claim 2

The method of treating a gas including the separation and removal of micron-size particulate matter by means of a filter of granular material which comprises: a. arranging granular material smaller than about 40 mesh in a panel bed having a plurality of transversely disposed upwardly spaced gas entry portions separated by interposed supporting members having outer and inner edges with respect to the bed wherein said gas entry portions have gas entry faces substantially contiguous with said outer edges and wherein said bed has gas exit portions spaced from said inner edges; b. forwardly flowing gas through the gas entry portions of the granular material bed and outwardly from the gas exit portions while adding to said gas a first increment of a element selected from the group consisting of granular of fibrous medium substantially smaller than about 120 mesh to separate and accumulate said medium in surface layer deposits at said gas entry faces wherein said gas enters said gas entry faces at a velocity greater than about 16 feet per minute during at least a part of this step (b); c. stopping the forward flow of said gas of step (b); d. causing a transient flow of gas to move in the direction in reverse to the flow of said gas in (b); e. said transient reverse flow producing first a rise at a given rate of rise and subsequently a fall in the pressure difference between said gas exit portions and said gas entry portions, said difference remaining greater than a first critical minimum difference for a time interval less than about 50 milliseconds, said first critical difference being that difference at which a steady flow of gas in said reverse direction just produces a localized spill of said granular material from said gas entry faces, and said difference produced by said transient reverse flow peaking to a top value beyond a second critical minimum difference, which is the pressure difference at which a transient flow of gas in said reverse direction producing said pressure difference at said rate of rise just initiates a body movement of said granular material toward said gas entry faces to spill a portion of the granular material and substantially all of said accumulated granular or fibrous medium and said accumulated micron-size particulate matter from the bed; f. supplying fresh granular material to replace material spilled from said gas entry portions; g. repeating the cycle of said steps (b), (c), (d), (e) and (f) at least two times; h. forwardly flowing gas through the gas entry portions of the granular material bed and outwardly from the gas exit portions while adding to said gas a first increment of said granular or fibrous medium at a rate of addition leSs than about 5 grams per cubic meter of said gas to separate and accumulate said medium in surface layer deposits at said gas entry faces wherein said gas first enters said gas entry faces at a first velocity greater than about 16 feet per minute until the pressure drop across said surface layer deposits reaches about 0.05 centimeters of water per foot per minute of said first velocity and then adding to said gas a second increment of said medium at a rate of addition less than about 5 grams per cubic meter of said gas while the gas enters said gas entry faces at a second velocity greater than about 16 feet per minute until said pressure drop increases by at least about 0.1 centimeters of water per foot per minute of said second velocity and wherein subsequently the rate of flow of said gas is reduced so that the gas enters said gas entry faces at a third velocity less than about one-half of said first velocity and of said second velocity and also less than about 16 feet per minute while adding to said gas at a rate of addition less than about 5 grams per cubic meter of said gas a third increment of said medium wherein said third increment is at least about 1.5 times as large as said second increment when said pressure drop increased with the addition of said second increment by about 0.1 centimeters of water per foot per minute and wherein, when said pressure drop increased by a substantially greater amount, said third increment is at least about 1.5 times as large as the pro rata portion of said second increment that was responsible for an increase of exactly 0.1 centimeter of water per foot per minute; i. stopping the forward flow of said gas of step (h) and forwardly flowing gas to be treated at a rate to enter said gas entry faces at a velocity not substantially greater than said third velocity and thereby treating said gas by contact with said surface layer deposits and thereby to separate and accumulate said micron-size particulate matter on said surface layer deposits of said granular or fibrous medium; j. stopping the forward flow of said gas of step (i); and k. repeating steps (d), (e), (f), (h), (i) and (j) in a cyclic manner.

Claim 11

THE METHOD OF TREATING A GAS INCLUDING THE SEPARATION AND REMOVAL OF MICRON-SIZE PARTICULATE MATTER BY MEANS OF A FILTER OF GRANULAR MATERIAL WHICH COMPRISES: A. ARRANGING GRANULAR MATERIA IN A PANEL BED HAVINF A PLURALITY OF TRANSVERSELY DISPOSED UPWARDLY SPACED GAS ENTRY PORTIONS SEPARATED BY INTERPOSED SUPPORTING MEMBERS HAVING OUTER AND INNER EDGES WITH RESPECT TO THE BED WHEREIN SAID GAS ENTRY PORTIONS HAVE GAS ENTRY FACES SUBSTANTIALLY CONTIGUOUS WITH SAID OUTER EDGES AND WHEREIN SAID BED HAS GAS EXIT PORTIONS SPACED FROM SAID INNER EDGES; B. FORWARDLY FLOWING GAS THROUGH THE GAS ENTRY PORTIONS OF THE GRANULAR MATERIAL BED AND OUTWARDLY FROM THE GAS EXIT PORTIONS WHILE ADDING TO SAID GAS A ELEMENT SELECTED FROM THE GROUP CONSISTING OF GRANULAR OR FIBROUS MEDIUM SUBSTANTIALLY SMALLER THAN ABOUT 120 MESH TO SEPARATE AND ACCUMULATE SAID MEDIUM IN SURFACE LAYER DEPOSITS AT SAID GAS ENTRY FACES WHEREIN SAID GAS ENTERS SAID GAS ENTRY FACES AT A VELOCITY GREATER THAN ABOUT 16 FEET PER MINUTE DURING AT LEAST A PART OF THIS STEP (B); C. THEREAFTER CAUSING A TRANSIENT FLOW OF GAS TO MOVE IN THE DIRECTION IN REVERSE TO THE FLOW OF SAID GAS IN (B) D. SAID TRANSIENT REVERSE TO THE FLOW PRODUCING FIRST A RISE AT RATE OF RISE AND SUBSEQUENTLY A FALL IN THE PRESSURE DIFFERENCE BETWEEN SAID GAS EXIT PORTIONS AND SAID ENTRY PORTIONS, SAID DIFFERENCE FOR A TIME INTERVAL LESS THAN CRITICAL MINIMUM DIFFERENCE FOR A TIME INTERVAL LESS THAN ABOUT 150 MILLISECONDS, SAID FIRST CRITICAL DIFFERENCE BEING THAT DIFFERENCE AT WHICH A STEADY FLOW OF GAS IN SAID REVERSE DIRECTION JUST PRODUCES A LOCALIZED SPILL OF SAID GRANULAR MATERIAL FROM SAID GAS ENTRY FACES, AND SAID DIFFERENCE PRODUCED BY SAID TRANSIENT REVERSE FLOW PEAKING TO A TOP VALUE BEYOND A SECOND CRITICAL MINIMUM DIFFERENCE WHICH IS THE PRESSURE DIFFERENCE AT WHICH A TRANSIENT FLOW OF GAS IN SAID REVERSE DIRECTION PRODUCING SAID PRESSURE DIFFERENCE AT SAID RATE OF RISE JUST INITIATES A BODY MOVEMENT OF SAID GRANULAR MATERIAL TOWARD SAID GAS ENTRY FACES TO SPILL A PORTION OF THE GRANULAR MATERIAL FROM THE BED; E. SUPPLYING FRESH GRANULAR MATERIAL TO REPLACE MATERIAL SPILLED FROM SAID GAS ENTRY PORTIONS; F. REPEATING THE CYCLE OF SAID STEPS (B), (C), (D), AND (E) AT LEAST TWO TIMES AND THEN REPEATING STEP (B); G. FORWARDLY FLOWING GAS TO BE TREATED THROUGH THE GAS ENTRY PORTIONS OF THE GRANULAR MATERIAL BED AND OUTWARDLY FROM THE GAS EXIT PORTION TO TREAT SAID GAS BY CONTACT WITH SAID SURFACE LAYER DEPOSITS AND THEREBY TO SEPARATE AND ACCUMULATE MICRON-SIZE PARTICULATE MATTER ON SAID SURFACE LAYER DEPOSITS OF SAID GRANULAR OR FIBROUS MEDIUM AND WHEREIN EITHER AT LEAST A FIRST PART OF THIS STEP (G) OCCURS SIMULTANEOUSLY WITH A SAID STEP (B), THE GAS IN (B) COMPRISING THE GAS TO BE TREATED, OR THIS STEP (G) IS WHOLLY SUBSEQUENTLY TO SAID STEP (B); AND H. THEREAFTER REPEATING STEPS (C) (D), (E), (B), AND (G) IN A CYCLIC MANNER.

Claim 12

THE METHOD OF TREATING A GAS INCLUDING THE SEPARATION AND REMOVAL OF MICRON-SIZE PARTICULATE MATTER BY MEANS OF A FILTER OF GRANULAR MATERIAL WHICH COMPRISES: A. ARRANGING GRANULAR MATERIA IN A PANEL BED HAVINF A PLURALITY OF TRANSVERSELY DISPOSED UPWARDLY SPACED GAS ENTRY PORTIONS SEPARATED BY INTERPOSED SUPPORTING MEMBERS HAVING OUTER AND INNER EDGES WITH RESPECT TO THE BED WHEREIN SAID GAS ENTRY PORTIONS HAVE GAS ENTRY FACES SUBSTANTIALLY CONTIGUOUS WITH SAID OUTER EDGES AND WHEREIN SAID BED HAS GAS EXIT PORTIONS SPACED FROM SAID INNER EDGES; B. FORWARDLY FLOWING GAS THROUGH THE GAS ENTRY PORTIONS OF THE GRANULAR MATERIAL BED AND OUTWARDLY FROM THE GAS EXIT PORTIONS WHILE ADDING TO SAID GAS A ELEMENT SELECTED FROM THE GROUP CONSISTING OF GRANULAR OR FIBROUS MEDIUM SUBSTANTIALLY SMALLER THAN ABOUT 120 MESH TO SEPARATE AND ACCUMULATE SAID MEDIUM IN SURFACE LAYER DEPOSITS AT SAID GAS ENTRY FACES WHEREIN SAID GAS ENTERS SAID GAS ENTRY FACES AT A VELOCITY GREATER THAN ABOUT 16 FEET PER MINUTE DURING AT LEAST A PART OF THIS STEP (B); C. THEREAFTER CAUSING A TRANSIENT FLOW OF GAS TO MOVE IN THE DIRECTION IN REVERSE TO THE FLOW OF SAID GAS IN (B) D. SAID TRANSIENT REVERSE TO THE FLOW PRODUCING FIRST A RISE AT RATE OF RISE AND SUBSEQUENTLY A FALL IN THE PRESSURE DIFFERENCE BETWEEN SAID GAS EXIT PORTIONS AND SAID ENTRY PORTIONS, SAID DIFFERENCE FOR A TIME INTERVAL LESS THAN CRITICAL MINIMUM DIFFERENCE FOR A TIME INTERVAL LESS THAN ABOUT 150 MILLISECONDS, SAID FIRST CRITICAL DIFFERENCE BEING THAT DIFFERENCE AT WHICH A STEADY FLOW OF GAS IN SAID REVERSE DIRECTION JUST PRODUCES A LOCALIZED SPILL OF SAID GRANULAR MATERIAL FROM SAID GAS ENTRY FACES, AND SAID DIFFERENCE PRODUCED BY SAID TRANSIENT REVERSE FLOW PEAKING TO A TOP VALUE BEYOND A SECOND CRITICAL MINIMUM DIFFERENCE WHICH IS THE PRESSURE DIFFERENCE AT WHICH A TRANSIENT FLOW OF GAS IN SAID REVERSE DIRECTION PRODUCING SAID PRESSURE DIFFERENCE AT SAID RATE OF RISE JUST INITIATES A BODY MOVEMENT OF SAID GRANULAR MATERIAL TOWARD SAID GAS ENTRY FACES TO SPILL A PORTION OF THE GRANULAR MATERIAL FROM THE BED; E. SUPPLYING FRESH GRANULAR MATERIAL TO REPLACE MATERIAL SPILLED FROM SAID GAS ENTRY PORTIONS; F. REPEATING THE CYCLE OF SAID STEPS (B), (C), (D), AND (E) AT LEAST TWO TIMES AND THEN REPEATING STEP (B); G. FORWARDLY FLOWING GAS TO BE TREATED THROUGH THE GAS ENTRY PORTIONS OF THE GRANULAR MATERIAL BED AND OUTWARDLY FROM THE GAS EXIT PORTION TO TREAT SAID GAS BY CONTACT WITH SAID SURFACE LAYER DEPOSITS AND THEREBY TO SEPARATE AND ACCUMULATE MICRON-SIZE PARTICULATE MATTER ON SAID SURFACE LAYER DEPOSITS OF SAID GRANULAR OR FIBROUS MEDIUM AND WHEREIN EITHER AT LEAST A FIRST PART OF THIS STEP (G) OCCURS SIMULTANEOUSLY WITH A SAID STEP (B), THE GAS IN (B) COMPRISING THE GAS TO BE TREATED, OR THIS STEP (G) IS WHOLLY SUBSEQUENTLY TO SAID STEP (B); AND H. THEREAFTER REPEATING STEPS (C) (D), (E), (B), AND (G) IN A CYCLIC MANNER.

Claim 22

A method of making coherent reinforced surface layer deposits for coordinately reinforcing the surface layer deposits and improving efficiency of filtration using such deposits in a renewable panel bed filter method for treating a gas including the separation and removal of micron-size particulate material, comprising: a. arranging a granular material in a panel bed having a plurality of transversely disposed upwardly spaced gas entry portions separated by interposed supporting members having outer and inner edges with respect to the bed wherein said gas entry portions have gas entry faces substantially contiguous with said outer edges and wherein said bed has gas exit portions spaced from said inner edges; b. forwardly flowing gas through the gas entry portions of the granular material bed and outwardly from the gas exit portions while adding to said gas element selected from the group consisting of granular or fibrous medium substantially smaller than about 120 mesh admixed with a reticulating agent to separate and accumulate said medium and reticulating agent in surface layer deposits at said gas entry faces wherein said gas enters said gas entry faces at a velocity greater than about 16 feet per minute during at least a part of this step (b) and wherein said reticulating agent establishes bonds between adjacent particules of said granular or fibrous medium at at least a fraction of the points of contact among particles of said medium to provide a reticular network of said particules thereby reinforcing said surface layer deposits and rendering the deposits less vulnerable to spalling or cracking under influence of vibrations or sudden change in pressure difference across the deposits on account of sudden change in gas flow; c. thereafter causing a transient flow of gas to move in the direction in reverse to the flow of said gas in (b); d. said transient reverse flow producing first a rise at a given rate of rise and subsequently a fall in the pressure difference between said gas exit portions and said gas entry portions, said difference remaining greater than a first critical minimum difference for a time interval less than about 150 milliseconds, said first critical difference being that difference at which a steady flow of gas in said reverse direction just produces a localized spill of said granular material from said gas entry faces, and said difference produced by said transient reverse flow peaking to a top value beyond a second critical minimum difference, which is the pressure difference at which a transient flow of gas in said reverse direction producing said pressure difference at said rate of rise just initiates a body movement of said granular material toward said gas entry faces to spill a portion of the granular material and substantially all of said accumulated granular or fibrous medium in said reinforced surface layer deposits from the bed; e. supplying fresh granular material to replace material spilled from said gas entry portions; f. repeating the cycle of said steps (b), (c), (d) and (e) at least two times and then repeating step (b); g. forwardly flowing gas to be treated through the gas entry portions of the granular material bed and outwardly from the gas exit portions to treat said gas by contact with said reinforced surface layer deposits of said granular or fibrous medium and thereby to separate and accumulate micron-size particulate matter on said surface layer deposits and wherein either at least a first part of the step (g) occurs simultaneously with a said step (b), the gas in (b) comprising the gas to be treated, or this step (g) is wholly subsequent to said step (b); and h. thereafter repeating steps (c), (d), (e), (b) and (g) in a cyclic manner.

Claim 23

A method of making coherent reinforced surface layer deposits for coordinately reinforcing the surface layer deposits and improving efficiency of filtration using such deposits in a renewable panel bed filter method for treating a gas including the separation and removal of micron-size particulate material, comprising: a. arranging a granular material in a panel bed having a plurality of transversely disposed upwardly spaced gas entry portions separated by interposed supporting members having outer and inner edges with respect to the bed wherein said gas entry portions have gas entry faces substantially contiguous with said outer edges and wherein said bed has gas exit portions spaced from said inner edges; b. forwardly flowing gas through the gas entry portions of the granular material bed and outwardly from the gas exit portions while adding to said gas element selected from the group consisting of granular or fibrous medium substantially smaller than about 120 mesh admixed with a reticulating agent to separate and accumulate said medium and reticulating agent in surface layer deposits at said gas entry faces wherein said gas enters said gas entry faces at a velocity greater than about 16 feet per minute during at least a part of this step (b) and wherein said reticulating agent establishes bonds between adjacent particules of said granular or fibrous medium at at least a fraction of the points of contact among particles of said medium to provide a reticular network of said particules thereby reinforcing said surface layer deposits and rendering the deposits less vulnerable to spalling or cracking under influence of vibrations or sudden change in pressure difference across the deposits on account of sudden change in gas flow; c. thereafter causing a transient flow of gas to move in the direction in reverse to the flow of said gas in (b); d. said transient reverse flow producing first a rise at a given rate of rise and subsequently a fall in the pressure difference between said gas exit portions and said gas entry portions, said difference remaining greater than a first critical minimum difference for a time interval less than about 150 milliseconds, said first critical difference being that difference at which a steady flow of gas in said reverse direction just produces a localized spill of said granular material from said gas entry faces, and said difference produced by said transient reverse flow peaking to a top value beyond a second critical minimum difference, which is the pressure difference at which a transient flow of gas in said reverse direction producing said pressure difference at said rate of rise just initiates a body movement of said granular material toward said gas entry faces to spill a portion of the granular material and substantially all of said accumulated granular or fibrous medium in said reinforced surface layer deposits from the bed; e. supplying fresh granular material to replace material spilled from said gas entry portions; f. repeating the cycle of said steps (b), (c), (d) and (e) at least two times and then repeating step (b); g. forwardly flowing gas to be treated through the gas entry portions of the granular material bed and outwardly from the gas exit portions to treat said gas by contact with said reinforced surface layer deposits of said granular or fibrous medium and thereby to separate and accumulate micron-size particulate matter on said surface layer deposits and wherein either at least a first part of the step (g) occurs simultaneously with a said step (b), the gas in (b) comprising the gas to be treated, or this step (g) is wholly subsequent to said step (b); and h. thereafter repeating steps (c), (d), (e), (b) and (g) in a cyclic manner.

Claim 38

A method for making coherent reinforced surface layer deposits of fly ash from combustion of pulverized coal on a renewable panel bed of a granular material for treating a gas including the separation and removal of micron-size particulate matter, comprising: a. arranging granular material smaller than about 20 mesh in a panel bed having a plurality of transversely disposed upwardly spaced gas entry portions separated by interposed supporting members having outer and inner edges with respect to the bed wherein said gas entry portions have gas entry faces substantially contiguous with said outer edges and wherein said bed has gas exit portions spaced from said inner edges; and b. forwardly flowing gas through the gas entry portions of the granular material bed and outwardly from the gas exit portions while adding to said gas a fly ash from the combustion of pulverized coal wherein the fly ash is substantially smaller than about 120 mesh and is admixed with a reticulating agent and wherein said fly ash admixed with said reticulating agent separates and accumulates in surface layer deposits at said gas entry faces and wherein said gas enters said gas entry faces during at least a part of this step (b) at a velocity greater than about 16 feet per minute and wherein said reticulating agent establishes bonds between adjacent particles of said fly ash at at least a fraction of the points of contact among said particles of said fly ash to provide a reticular network of said particles and rendering the deposits less vulnerable to spalling or cracking under influence of vibrations or sudden change in pressure difference across the deposits on account of sudden change in gas flow; c. thereafter causing a transient flow of gas to move in the direction in reverse to the flow of said gas in (b); d. said transient reverse flow producing first a rise at a given rate of rise and subsequently a fall in the pressure difference between said gas exit portions and said gas entry portions, said difference remaining greater than a first critical minimum difference for a time interval less than about 50 milliseconds, said first critical difference being that difference at which a steady flow of gas in said reverse direction just produces a localized spill of said granular material from said gas entry faces, and said difference produced by said transient reverse flow peaking to a top value beyond a second critical minimum difference, which is the pressure difference at which a transient flow of gas in said reverse direction producing said pressure difference at said rate of rise just initiates a body movement of said granular material toward said gas entry faces to spill a portion of the granular material and said reinforced surface layer deposits from the bed; e. supplying fresh granular material to replace material spilled from said gas entry portions; and f. repeating the cycle of said steps (b), (c), (d), and (e) at least two times and then repeating step (b) to make coherent reinforced surface layer deposits of fly ash.

Claim 39

A method for making coherent reinforced surface layer deposits of fly ash from combustion of pulverized coal on a renewable panel bed of a granular material for treating a gas including the separation and removal of micron-size particulate matter, comprising: a. arranging granular material smaller than about 20 mesh in a panel bed having a plurality of transversely disposed upwardly spaced gas entry portions separated by interposed supporting members having outer and inner edges with respect to the bed wherein said gas entry portions have gas entry faces substantially contiguous with said outer edges and wherein said bed has gas exit portions spaced from said inner edges; and b. forwardly flowing gas through the gas entry portions of the granular material bed and outwardly from the gas exit portions while adding to said gas a fly ash from the combustion of pulverized coal wherein the fly ash is substantially smaller than about 120 mesh and is admixed with a reticulating agent and wherein said fly ash admixed with said reticulating agent separates and accumulates in surface layer deposits at said gas entry faces and wherein said gas enters said gas entry faces during at least a part of this step (b) at a velocity greater than about 16 feet per minute and wherein said reticulating agent establishes bonds between adjacent particles of said fly ash at at least a fraction of the points of contact among said particles of said fly ash to provide a reticular network of said particles and rendering the deposits less vulnerable to spalling or cracking under influence of vibrations or sudden change in pressure difference across the deposits on account of sudden change in gas flow; c. thereafter causing a transient flow of gas to move in the direction in reverse to the flow of said gas in (b); d. said transient reverse flow producing first a rise at a given rate of rise and subsequently a fall in the pressure difference between said gas exit portions and said gas entry portions, said difference remaining greater than a first critical minimum difference for a time interval less than about 50 milliseconds, said first critical difference being that difference at which a steady flow of gas in said reverse direction just produces a localized spill of said granular material from said gas entry faces, and said difference produced by said transient reverse flow peaking to a top value beyond a second critical minimum difference, which is the pressure difference at which a transient flow of gas in said reverse direction producing said pressure difference at said rate of rise just initiates a body movement of said granular material toward said gas entry faces to spill a portion of the granular material and said reinforced surface layer deposits from the bed; e. supplying fresh granular material to replace material spilled from said gas entry portions; and f. repeating the cycle of said steps (b), (c), (d), and (e) at least two times and then repeating step (b) to make coherent reinforced surface layer deposits of fly ash.

Claim 43

The method of treating a gas including the separation and removal of micron-size partIculate matter by means of a filter of granular material which comprises a. arranging granular material in a panel bed having a plurality of transversely disposed upwardly spaced gas entry portions separated by interposed supporting members, a typical said member having an upper and a lower surface each having outer and inner edges with respect to the bed wherein said surfaces are articulated at an edge joint at their respective inner edges and wherein each of said surfaces is gently curved and inclines downwardly and inwardly from its outer edge and then upwardly and inwardly toward said edge joint and wherein said upper surface of a given member and the said lower surface of the next superjacent member cooperate to support and retain a said gas entry portion having gas entry face substantially contiguous but not in perfect contiguity with said outer edges of said surfaces, and wherein said bed has gas exit portions spaced from the inner edge joints of said members; b. forwardly flowing gas through the gas entry portions of the granular material bed and outwardly from the gas exit portions while adding to said gas a element selected from the group consisting of granular or fibrous medium substantially smaller than about 120 mesh to separate and accumulate said medium in surface layer deposits at said gas entry faces wherein said gas enters said gas entry faces at a velocity greater than about 16 feet per minute during at least a part of this step (b); c. thereafter causing a transient flow of gas to move in the direction in reverse to the flow of said gas in (b); d. said transient reverse flow producing first a rise at a given rate of rise and subsequently a fall in the pressure portions, said difference remaining greater than a first critical minimum difference for a time interval less than about 150 milliseconds, said first critical difference being that difference at which a steady flow of gas in said reverse direction just produces a localized spill of said granular material from said gas entry faces, and said difference produced by said transient reverse flow peaking to a top value beyond a second critrical minimum difference, which is the pressure difference at which a transient flow of gas in said reverse direction producing said pressure difference at said rate of rise just initiates a body movement of said granular material toward said gas entry faces to bring said faces into perfect contiguity with said outer edges of said upper and lower surfaces and to spill a portion of the granular material and substantially all of said accumulated granular or fibrous medium from the bed; e. supplying fresh granular material to replace material spilled from said gas entry portions; f. causing a gas to flow suddenly forwardly through the gas entry portions of the granular material bed to cause a body movement of said gas entry portions inwardly coordinately with a decrease in the porosity of said bed and thereby to move said gas entry faces a short distance away from perfect contiguity with said outer edges of said upper and lower surfaces of said members; g. repeating the cycle of said steps (b), (c), (d), (e), and (f) at least two times and then repeating step (b); h. forwardly flowing gas to be treated through the gas entry portions of the granular material bed and outwardly from the gas exit portions to separate and accumulate micron-size particulate matter on said surface layer deposits of said granular or fibrous medium and wherein either at least a first part of this step (h) occurs simultaneously with a said step (b), the gas in (b) comprising the gas to be treated, to this step (h) being wholly subsequent to said step (b); and i. thereafter repeating steps (c) (d), (e), (f), (b), and (h) in a cyclic manner.

Claim 44

The method of treating a gas including the separation and removal of micron-size partIculate matter by means of a filter of granular material which comprises a. arranging granular material in a panel bed having a plurality of transversely disposed upwardly spaced gas entry portions separated by interposed supporting members, a typical said member having an upper and a lower surface each having outer and inner edges with respect to the bed wherein said surfaces are articulated at an edge joint at their respective inner edges and wherein each of said surfaces is gently curved and inclines downwardly and inwardly from its outer edge and then upwardly and inwardly toward said edge joint and wherein said upper surface of a given member and the said lower surface of the next superjacent member cooperate to support and retain a said gas entry portion having gas entry face substantially contiguous but not in perfect contiguity with said outer edges of said surfaces, and wherein said bed has gas exit portions spaced from the inner edge joints of said members; b. forwardly flowing gas through the gas entry portions of the granular material bed and outwardly from the gas exit portions while adding to said gas a element selected from the group consisting of granular or fibrous medium substantially smaller than about 120 mesh to separate and accumulate said medium in surface layer deposits at said gas entry faces wherein said gas enters said gas entry faces at a velocity greater than about 16 feet per minute during at least a part of this step (b); c. thereafter causing a transient flow of gas to move in the direction in reverse to the flow of said gas in (b); d. said transient reverse flow producing first a rise at a given rate of rise and subsequently a fall in the pressure portions, said difference remaining greater than a first critical minimum difference for a time interval less than about 150 milliseconds, said first critical difference being that difference at which a steady flow of gas in said reverse direction just produces a localized spill of said granular material from said gas entry faces, and said difference produced by said transient reverse flow peaking to a top value beyond a second critrical minimum difference, which is the pressure difference at which a transient flow of gas in said reverse direction producing said pressure difference at said rate of rise just initiates a body movement of said granular material toward said gas entry faces to bring said faces into perfect contiguity with said outer edges of said upper and lower surfaces and to spill a portion of the granular material and substantially all of said accumulated granular or fibrous medium from the bed; e. supplying fresh granular material to replace material spilled from said gas entry portions; f. causing a gas to flow suddenly forwardly through the gas entry portions of the granular material bed to cause a body movement of said gas entry portions inwardly coordinately with a decrease in the porosity of said bed and thereby to move said gas entry faces a short distance away from perfect contiguity with said outer edges of said upper and lower surfaces of said members; g. repeating the cycle of said steps (b), (c), (d), (e), and (f) at least two times and then repeating step (b); h. forwardly flowing gas to be treated through the gas entry portions of the granular material bed and outwardly from the gas exit portions to separate and accumulate micron-size particulate matter on said surface layer deposits of said granular or fibrous medium and wherein either at least a first part of this step (h) occurs simultaneously with a said step (b), the gas in (b) comprising the gas to be treated, to this step (h) being wholly subsequent to said step (b); and i. thereafter repeating steps (c) (d), (e), (f), (b), and (h) in a cyclic manner.