EP0126619B1 - Procédé et dispositif de combustion des matériaux - Google Patents
Procédé et dispositif de combustion des matériaux Download PDFInfo
- Publication number
- EP0126619B1 EP0126619B1 EP19840303312 EP84303312A EP0126619B1 EP 0126619 B1 EP0126619 B1 EP 0126619B1 EP 19840303312 EP19840303312 EP 19840303312 EP 84303312 A EP84303312 A EP 84303312A EP 0126619 B1 EP0126619 B1 EP 0126619B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- combustion
- chamber
- solids
- zone
- air
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000002485 combustion reaction Methods 0.000 title claims description 192
- 238000000034 method Methods 0.000 title claims description 43
- 239000000463 material Substances 0.000 title claims description 38
- 239000007787 solid Substances 0.000 claims description 180
- 239000007789 gas Substances 0.000 claims description 77
- 239000003245 coal Substances 0.000 claims description 41
- 238000012546 transfer Methods 0.000 claims description 29
- 239000000567 combustion gas Substances 0.000 claims description 23
- 239000004576 sand Substances 0.000 claims description 22
- 239000010802 sludge Substances 0.000 claims description 21
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 claims description 17
- 229910052815 sulfur oxide Inorganic materials 0.000 claims description 14
- 239000000203 mixture Substances 0.000 claims description 12
- 238000005243 fluidization Methods 0.000 claims description 11
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 10
- 229910052717 sulfur Inorganic materials 0.000 claims description 10
- 239000011593 sulfur Substances 0.000 claims description 10
- 238000004064 recycling Methods 0.000 claims description 7
- 239000011343 solid material Substances 0.000 claims description 7
- 238000002156 mixing Methods 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 5
- 150000001875 compounds Chemical class 0.000 claims description 4
- 230000001590 oxidative effect Effects 0.000 claims description 4
- 239000010813 municipal solid waste Substances 0.000 claims description 3
- -1 refuse Substances 0.000 claims description 3
- 239000010801 sewage sludge Substances 0.000 claims description 3
- 239000000571 coke Substances 0.000 claims description 2
- 239000012530 fluid Substances 0.000 claims description 2
- 239000003077 lignite Substances 0.000 claims description 2
- 239000003027 oil sand Substances 0.000 claims description 2
- 239000003415 peat Substances 0.000 claims description 2
- 239000002023 wood Substances 0.000 claims description 2
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 claims 1
- 229910000037 hydrogen sulfide Inorganic materials 0.000 claims 1
- 239000000446 fuel Substances 0.000 description 38
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 33
- 235000019738 Limestone Nutrition 0.000 description 30
- 239000006028 limestone Substances 0.000 description 30
- 239000010459 dolomite Substances 0.000 description 24
- 229910000514 dolomite Inorganic materials 0.000 description 24
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 21
- 239000003546 flue gas Substances 0.000 description 14
- 239000000047 product Substances 0.000 description 13
- 239000002956 ash Substances 0.000 description 11
- 238000001816 cooling Methods 0.000 description 10
- 238000010791 quenching Methods 0.000 description 10
- 230000003750 conditioning effect Effects 0.000 description 9
- 230000008901 benefit Effects 0.000 description 7
- 238000010304 firing Methods 0.000 description 7
- 239000007788 liquid Substances 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 6
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 6
- 239000002245 particle Substances 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 239000007921 spray Substances 0.000 description 6
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 5
- 239000000654 additive Substances 0.000 description 5
- 238000011084 recovery Methods 0.000 description 5
- 239000004215 Carbon black (E152) Substances 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 4
- 229930195733 hydrocarbon Natural products 0.000 description 4
- 150000002430 hydrocarbons Chemical class 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000005855 radiation Effects 0.000 description 4
- 239000003039 volatile agent Substances 0.000 description 4
- 239000002699 waste material Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 230000000996 additive effect Effects 0.000 description 3
- 239000002585 base Substances 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- TXKMVPPZCYKFAC-UHFFFAOYSA-N disulfur monoxide Inorganic materials O=S=S TXKMVPPZCYKFAC-UHFFFAOYSA-N 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 3
- 239000010881 fly ash Substances 0.000 description 3
- 239000003779 heat-resistant material Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 239000004449 solid propellant Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- RAHZWNYVWXNFOC-UHFFFAOYSA-N sulfur dioxide Inorganic materials O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 3
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- 230000003134 recirculating effect Effects 0.000 description 2
- 230000001172 regenerating effect Effects 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 238000005201 scrubbing Methods 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 238000003892 spreading Methods 0.000 description 2
- 230000007480 spreading Effects 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 238000009834 vaporization Methods 0.000 description 2
- 230000008016 vaporization Effects 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- IOVCWXUNBOPUCH-UHFFFAOYSA-N Nitrous acid Chemical class ON=O IOVCWXUNBOPUCH-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 description 1
- 239000003830 anthracite Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- 235000012255 calcium oxide Nutrition 0.000 description 1
- GBAOBIBJACZTNA-UHFFFAOYSA-L calcium sulfite Chemical compound [Ca+2].[O-]S([O-])=O GBAOBIBJACZTNA-UHFFFAOYSA-L 0.000 description 1
- 235000010261 calcium sulphite Nutrition 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 230000001143 conditioned effect Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000011162 core material Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 239000013056 hazardous product Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 206010022000 influenza Diseases 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000010985 leather Substances 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 239000013528 metallic particle Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 239000002991 molded plastic Substances 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- NJPPVKZQTLUDBO-UHFFFAOYSA-N novaluron Chemical compound C1=C(Cl)C(OC(F)(F)C(OC(F)(F)F)F)=CC=C1NC(=O)NC(=O)C1=C(F)C=CC=C1F NJPPVKZQTLUDBO-UHFFFAOYSA-N 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000000123 paper Substances 0.000 description 1
- 239000011236 particulate material Substances 0.000 description 1
- 239000002985 plastic film Substances 0.000 description 1
- 229920006255 plastic film Polymers 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 238000011027 product recovery Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical class [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 1
- 150000003464 sulfur compounds Chemical class 0.000 description 1
- AKEJUJNQAAGONA-UHFFFAOYSA-N sulfur trioxide Chemical class O=S(=O)=O AKEJUJNQAAGONA-UHFFFAOYSA-N 0.000 description 1
- 239000011269 tar Substances 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
- F23G5/20—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having rotating or oscillating drums
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23B—METHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
- F23B1/00—Combustion apparatus using only lump fuel
- F23B1/30—Combustion apparatus using only lump fuel characterised by the form of combustion chamber
- F23B1/32—Combustion apparatus using only lump fuel characterised by the form of combustion chamber rotating
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
- F23G5/44—Details; Accessories
- F23G5/46—Recuperation of heat
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G2209/00—Specific waste
- F23G2209/12—Sludge, slurries or mixtures of liquids
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G2209/00—Specific waste
- F23G2209/24—Contaminated soil; foundry sand
Definitions
- the overfeed firing method of combustion is relatively inefficient because of the difficulty in achieving complete and even combustion of the fuel and, furthermore, most sulfur-containing fuels require the addition of complex and expensive external scrubbing systems to the furnace.
- fuel is introduced into a chamber where a series of pushers or rams move the fuel upward for spreading between air-admitting tuyeres and side-grates. As the fuel rises in the chamber, it is ignited by the heat from the burning fuel above and continues to burn as the incoming raw fuel forces the fuel bed upward.
- Underfeed firing has many of the same disadvantages as overfeed firing and, furthermore, the ash content must be critically controlled between 3 and 10% so as not to become a hindrance to proper combustion.
- Pulverized fuel burning In pulverized fuel combustion, the fuel is pulverized and then mixed with transport air for conveyance to the furnace where it is burned. Pulverized fuel burning has many drawbacks including the cost of pulverization and the production of large quantities of fly ash which may require the installation of particulate-removal equipment which also adds to the cost of the system.
- fluidized bed combustion the combustible materials are usually ground to a suitable size enabling their fluidization in a stream of high velocity air and combustion takes place in the fluidized bed.
- the fluidized bed method requires a significant amount of energy to maintain its fluidized state and the temperatures of operation are relatively low.
- a major disadvantage of this last technique is the incomplete combustion of fines which are swept out of the fluidized bed by the air stream and require either capture and reinjection or burn-out of the carbon in a separate bed.
- powdered or crushed additives such as limestone or dolomite may be added to the fuel for reaction with the sulfur oxides within the furnace.
- This method is inefficient in systems which burn pulverized fuel because of the relatively high furnace temperatures employed.
- fluidized bed combustion where the temperature is favorable, a substantial part of the sulfur oxides fails to react with the additive and may escape to the atmosphere unless an excess of limestone or dolomite is used.
- a number of other problems are encountered by employing limestone or dolomite additives in a fluidized bed.
- the size of the additive must be controlled such that it is carried out of the system with the fly ash but this does not usually provide optimum reaction time and conditions, or the additive must be of such size as the coal, in which case it becomes coated with calcium sulfate reaction product thereby allowing only a small part of the limestone to react.
- the most common solution to the aforementioned problems is to provide an excess of limestone or dolomite to make up for the unreacted material.
- waste is a term of art which connotes a conglomeration of such diverse materials as cardboard, newspaper, plastic film, leather, molded plastics, rubber, garbage, fluid, stones and metallics, etc. as indicated, for example, in the American Paper Institute Report No. 114, September 11, 1967.
- a combustion apparatus is shown with a cylindrical combustion chamber which rotates about its own axis and a device for supplying air to the chamber as it turns. Particulate material is introduced into the chamber and the combustible component is retorted in a bed of sand.
- GB Patent No. 1144403 describes a combustion apparatus comprising a combustion chamber having helical fins mounted on the interior of the chamber which serve to feed material, on rotation of the chamber, from a feed end of the chamber to the other end of the chamber, during which feeding the material is burnt.
- the burnt residue is unloaded by reversing the direction of rotation of the chamber so that the fins move the residue back to the feed end where it is discharged and removed. The cycle is then repeated with new material.
- a combustion apparatus for particulate solids having a combustible component comprises a rotatable elongated combustion chamber for rotation about a substantially horizontal axis, means for introducing the particulate solids having a combustible component into the chamber for combustion of the combustible component, means for lifting and cascading the particulate solids in the chamber, and means for passing a stream of combustion gas through the chamber whereby combustion is achieved with the chamber with a mechanical fluidization of the particulate solids in the combustion gas during combustion characterised in that means are provided for recycling hot spent solids for mixing with the particulate solids operative to pick up a portion of the hot spent solids from a point close to the outlet end of the combustion chamber and to return them to a point close to the inlet end of the chamber.
- a method for combustion comprises introducing particulate solids having a combustible component into a rotatary elongated combustion chamber for rotation about a substantially horizontal axis, rotating the chamber about its horizontal axis, introducing an oxidizing gas into the chamber for combustion of the combustible component, passing a stream of combustion gas through the chamber through the stream of combustion gas, thereby achieving mechanical fluidization of the solids in the combustion gas during combustion characterised in that the method further comprises recycling hot spent solids for mixing with the particulate solids by picking up a portion of the hot spent solids from a point close to the outlet end of the combustion chamber and returning them to a point close to the inlet end of the chamber.
- the advantages of recycling hot solids are that the combustible feedstock is preheated, conditioned and it may be kept free-flowing in the case of sticky solids. This permits the combustion of so called'caking' coals, for example, which tend to form sticky masses during combustion. These sticky masses cause considerable difficulty in fluidized beds and other conventional methods of combustion.
- the combustion chamber is rotated about its horizontal axis at a speed defined by the following empirical relationship: in which A has a value between about 10 and 40 more preferably between 15 and 25.
- the invention may be used for the combustion of diverse materials particularly combustible solids, gases or liquids, and mixtures thereof.
- the invention provides an economic and efficient method of carrying out the combustion of such particulate solid fuel compositions.
- organic or hydrocarbon-containing materials such as sewage sludge, coal, tar sands, coal shale, coal tailings, refinery sludge, municipal refuse, spent foundry sand, oily mill scale, among other types of incineratable materials, may be disposed of utilizing this invention.
- heat may be recovered from such diverse combustible or waste materials for useful purposes, particularly for utilisation in steam boilers, i.e. those employed in a utility power plant or industrial steam plant.
- the combustion apparatus has mechanical means on its internal surface which, when rotated about its horizontal axis at a suitable speed, allows solids to become “mechanically fJuidized” and to cascade down through a stream of combustion gas in the apparatus.
- the cascading action of the hot solids establishes intimate contact with the combustion gas or other gases formed in the combustion section in a manner somewhat analogous to the contact in a fluidized bed and, it may be said analogously that the solids become "mechanically fluidized”.
- the necessity of fluidization by a high-velocity stream of gas is obviated as are the high-energy requirements associated with it.
- the invention also eliminates the need for expensive pulverizers, high pressure air handling systems, external pollution control devices and other complex or unreliable equipment. Many of the other disadvantages associated with the above-described systems of the prior art are overcome using the apparatus and method of the invention.
- the invention preferably provides a method and apparatus for optimizing heat transfer, solids and gas contacting, and solids transport in combustion of solid materials.
- the invention also enables the combustion of a wide variety of diverse materials and the recovery of heat therefrom for useful purposes.
- the combustion apparatus of this invention comprises a rotary chamber, i.e., a cylindrical drum, or other similar regularly shaped chamber, suitable for rotation about a substantially horizontal axis.
- the combustion chamber has an inlet and an outlet whereby the combustible materials are introduced at the feed end and any residual solids may exit at the outlet end.
- the invention is particularly adaptable to fuels which have a high volatiles content and the apparatus provides zones of combustion thereby insuring that the volatiles be driven off and combusted in the gas stream, while allowing suitable residence time to insure complete combustion of the remaining char or carbonaceous residue.
- ignition zone a short initial combustion zone
- principal combustion zone a relatively constant temperature combustion zone
- stratal combustion zone a relatively constant temperature combustion zone
- sensible heat in the gases and solids may be used in steam generation.
- the gases and solids are cooled before they enter a short disengaging section from which they leave the combustor separately at the outlet.
- the method for combusting a feedstock of particulate combustible solids employing the rotary elongated combustion chamber above mentioned includes the following steps.
- the combustible particulate solids or particulate solids containing a combustible component are first introduced into the rotary elongated chamber which is adapted for rotation about a substantially horizontal axis.
- the chamber has an inlet and an outlet and, preferably, mechanical means on the inside surface of the chamber for lifting and cascading the combustible solids through a stream of combustion gas in the chamber. Additionally, there is a means for introducing an oxidising gas into the chamber.
- the feedstock solids are subjected to combustion and heat may be recovered therefrom.
- combustion air introduction means is located near the inlet or feed end of the rotary combustion chamber where the particulate combustible solids are introduced.
- lifters are attached to the inside surface of the chamber to provide a means for lifting and cascading the combustible solids in the chamber and, by introducing air near the inlet of the combustion chamber, the combustion gases or burning fuel mixture establish an intimate contact of the cascading combustible solids with the gases in the combustor such that it may be said that the feedstock becomes mechanically fluidized as stated above.
- the means for lifting and cascading preferably comprises a plurality of lifters attached to the interior of the combustion chamber.
- the inner surface of the chamber is lined with a refractory heat-resistant material.
- a combined solid cooler/air preheater section may be provided after the combustion section for heating ambient combustion air to provide the air for introduction into the combustion section and to cool solids simultaneously passing through the preheater section.
- the lifters attached to the interior of the combustion chamber stand into the chamber distance of up to about 1/40 to 1/10 the diameter of the combustion section.
- the solid materials are lifted by said lifting means in the combustion chamber while the chamber is rotating at a speed defined by the following empirical relationship: in which A may have a valve between about 10 and 40, with valves 15 to 25 preferred, such that the gas is entrained by the cascading solid material resulting in mechanical fluidization.
- the apparatus for recycling hot solids downstream from the inlet end of the combustion chamber preferably comprises an open-ended, closed helical duct formed about an outer wall of the combustion chamber in a direction counter to its direction for rotation for picking up a portion of the solids from a point close to the outlet end of the combustion chamber and returning the solids to a point close to the inlet or ignition end of the chamber.
- Recirculation of the hot solids to the feed end as indicated above serves the purpose of rapidly bringing the cold combustible mixture up to the ignition temperature.
- the amount of recirculated material may be as high as 30 parts recirculated to 1 part of feed, or much smaller amount may be recirculated depending upon the characteristics of the coal or other combustible being combusted and upon the air preheat temperature.
- the circulation is thus accomplished in a considerably simpler more energy efficient manner than in a conventional fluidized bed combustor which requires removal of the recirculated solids from the overhead gas stream and reinjection into the bottom of the fluidized bed which is at a considerably higher pressure.
- a heat transfer coil or bundle may be mounted inside a rotating chamber.
- the bundle may be similar to the so-called U-tube bundle found in conventional heat exchangers.
- Other arrangements may also be used such as a fixed tube sheet bundle with no shell.
- the tubes would have water flowing internally and their external surfaces are exposed to hot gases formed by combustion of the combustible solids throughout the rotary combustor. As the hot solids are cascaded by means of the lifters and are mechanically fluidized, they pass over the external surface of the water-filled tubes transferring additional heat and, at the same time, entrained hot gases also transfer a portion of their heat to the liquid inside the tubes.
- the juxtaposition of the incandescent particles insures a high rate of radiant heat transfer as well as convection heat transfer.
- the combined heats from the hot gases and the cascading solids result in the heating and vaporization of the water inside the tubes resulting in the formation of steam, for example.
- water may simply be heated rather than generating steam.
- hot gases may be used externally to the apparatus for steam manufacture or other purposes. In some cases, the temperature of the hot gases may be controlled by the addition of excess air quantities.
- an improved apparatus for carrying out the combustion of coal or other hydrocarbon-containing solid combustible material is provided which effectively eliminates disadvantages of the coal combustors of the prior art.
- an improved coal furnace for the purpose of generating steam is provided.
- coal or other combustible is fed into one end of the rotating combustion chamber.
- the combustion chamber is equipped with internal lifters and, in some cases, recirculating chutes may be provided.
- the combustion chamber is rotated at a suitable speed to allow for the mechanical fluidization whereby the combustible coal solids cascade down through the flue gases formed by the combustion, or entraining gases during this operation.
- sulfur oxide gases may be formed during combustion of the coal fuel by oxidation of the sulfur, such gases may be simultaneously reacted during combustion with limestone or dolomite in the feedstock yielding a flue gas in which the sulfur oxides are greatly reduced, thereby making it very desirable from an environmental point of view.
- the nature of the "mechanical fluidization" produced by the cascading solids through the gas stream is such that the solid fuel mixture, for example coal and limestone or dolomite, does not have to be crushed to the same degree of uniform size as it does in the case of the conventional fluidized bed, thus eliminating the significant cost of relatively fine grinding and sizing the feed. In the preferred apparatus, all particle sizes are treated virtually the same as far as the combustion and reaction are concerned.
- the method of handling the limestone or dolomite represents a distinct advantage over the fluidized method of combustion.
- the limestone or dolomite in the fluidized bed method, must be of a size similar to the fuel in order to maintain these particles in the fluidized state.
- the limestone or dolomite must be relatively uniform and large in size to insure fluidization and to prevent it from being carried out with the flue gases.
- Such large-size particles also become coated with the sulfur oxide reaction products thereby preventing the unreacted core material from easily reacting.
- limestone or dolomite particles may be introduced in a finer state than the fuel, thus increasing their relative reactivity and increasing their exposed surface area. This results in a reduction in the limestone or dolomite requirements by comparison.
- the apparatus and method of this invention provides for fully continuous and integrated processes where combustible particulate solids or solids containing a combustible component, may be burned and provide useful sources of heat.
- the particulate solids may have a range of sizes, limited only by the size and dimension of the apparatus for passage of the solids therethrough.
- the invention may also offer a very distinct advantage in that it enables the direct transfer of process heat. Hot recycled spent solids also provides heat as indicated above to either condition the incoming feedstock or to bring it up to ignition temperature. Moreover, high rates of heat and mass transfer result in relatively small volume units that compare to conventional furnaces or furnace boilers.
- a highly efficient process is provided and additional recovery of heat from the flue gases indirectly may be achieved by heat exchange with the incoming air since a hot flue gas duct may also be constructed.to traverse a solids cooler/air preheater section. Furthermore, as indicated above, the solids cooier/air preheater section may be employed enabling the solids to heat incoming combustion air.
- the hot flue gases may also be sent through a waste heat boiler for generation of process steam or to provide other heat recovery.
- Another advantage of the invention is that combustible solids or solids-sludge mixtures are prevented from agglomerating in the unit by recirculation of the spent solids which acts as a coating agent for sticky materials which may be formed or released in the combustion section, thus keeping such materials free-flowing. It will be appreciated, in view hereof, that the transport of solids through the unit is accomplished without high-energy requirements that are characteristic of other conventional systems.
- the temperature of the combustion may be controlled in the range of 1200°F to 1600°F, (645°C to 875°C), for example, which in turn reduces the formation of nitrogen oxides. Also by reducing the ratio of actual to stoichiometric air, the nitrogen oxides may be reduced, resulting in total nitrogen oxide concentrations in the exhaust gases as low as 100 ppm.
- a further advantage of the invention is that gases undergo exceedingly low-pressure drop across the combustion chamber as compared to a fluidized bed combustor wherein the air must be sufficiently compressed to cause it to pass through a distributor and maintain sufficient velocity to fluidize the solids.
- the control of operating temperature may be affected in the combustion chamber by several means.
- introduction of combustion air at different locations within the combustor may provide a shortage of air in the initial combustion zone with additional air being added at some point in the principal combustion zone.
- spent dolomite at its lower discharge temperature may be recirculated to the feed end resulting in temperature reduction at this point of the combustor.
- Turn-down of the operating capacity may be easily brought about. Simple reduction in the feed rate of combustible solids would quickly cut down the amount of hot gases and, therefore, the amount of steam manufactured. A limiting condition would be the point at which sufficient heat is removed by the tube bundle so that combustion is no longer supported. Another effective means of turning the capacity down would be to reduce the speed of rotation of the combustion chamber to the point that cascading of solids no longer occurs.
- the combustible solids or solids containing combustible components which may be processed according to the method and apparatus of invention vary over wide classes of chemical constitution. Any solid which may be subjected to combustion may be employed. Furthermore, any combustible liquid, gas, mixtures of liquids and solids, and various combinations of such combustible materials, may also be employed providing that included in the combustible feedstock or recycle materials is a particulate solid material.
- a preferred class of combustible solids include hydrocarbon-containing minerals.
- this class are those materials selected from the group of bituminous or anthracite coal, coke, lignite, peat, combustible garbage, refuse, sewage or refinery sludge, coal shale, coal tailings, spent foundry sand, tar sands, oily mill scale, oil sand, wood, mixtures of these materials or other materials.
- this invention is especially directed to the recovery of heat from such sources of organic or hydrocarbon-containing materials such as coal for use in a steam boiler.
- a further advantage of the present invention is that when employing such combustible solids such as coal having undesirable chemical constituents such as sulfur-containing compounds, such compounds are also capable of being removed from the combustible solids without undesirable environmental pollution.
- limestone, dolomite or other absorbent, adsorbent or reactants are capable of removing such sulfur-containing compounds. This may be accomplished in a number of manners by operating, for example, at temperatures favorable to S02 sorption thereby eliminating an important environmental problem.
- Favorable operating temperatures in the combustion section are maintained between about 1200°F and 1600°F (645°C and 875°C) for such purpose.
- the invention provides a simple compact combustion apparatus having a heat transfer surface suitable for vaporization or heating of water or other liquid and wherein stabilized conditions of combustion occur at least in part in direct contact with the heat transfer surface.
- internal or external recirculation chutes are provided by this invention which permit recirculation of hot spent solids, for example, from the discharge end of the combustion zone to the inlet end of the ignition zone for the purpose of furnishing heat to the incoming solids.
- this invention provides for efficient and controllable combustion over a 4 to 5-fold range of variation of the combustion range from minimum to maximum operating rates of the rotary combustor.
- the apparatus also provides for an accelerated heat transfer to internally distributed heat transfer surfaces by utilization of the radiation, convection and conduction modes of heat transfer from cascading incandescent solids in contact with the heat transfer surfaces.
- a mechanical fluidization of the solids in the combustion zone from the inlet end to the spent discharge end assures efficient conditions of combustion for the residual carbon in the combustible particulate solids, particularly in the recycle of such spent materials as in one of the preferred embodiments of this invention.
- This phenomenon might also be referred to as cascade turbulence throughout the combustion zone which intensifies and accelerates the combustion process, thereby assuring a compact and low-cost apparatus.
- this invention provides a means of transferring solids through a rotary apparatus for combustion without consuming energy in the transfer except for the rotation of the rotary apparatus or drum itself without the necessity for complex external or internal transfer devices.
- solids recycle chutes and ducts are an integral part of the assembly to assure economy in construction, erection and operation of the system.
- an apparatus is provided in which the high rates of heat and mass transfer result in a very efficient use of volume, thus reducing the required size of the apparatus.
- Figure 1 is a side elevation in cross-section along the longitudinal axis of a rotary combustor in accordance with the invention by a plane perpendicular to the base with a combustor having an internal U-tube bundle which rotates with the combustor,
- Fig. 1 depicts one example of a rotary combustion apparatus in accordance with the principles of this invention.
- the following description relates to the use of coal as the combustible solids, mixed with limestone or dolomite in a proportion related to the sulfur content of the combustible coal.
- the combustion apparatus of Fig. 1 includes a cylindrical chamber 2 supported for rotation by cylindrical tires 3 and driven by a variable-speed drive in a conventional manner (not shown).
- Chamber 2 is lined with a refractory heat-resistant material 24 of a type suitable to withstand the maximum temperatures attained during combustion.
- Combustion air usually preheated but not necessarily, is introduced at the feed or inlet end by means of a stationary duct 4 which is sealed into the cylinder feed end-plate by a simple, conventional rotating seal 5.
- the quantity of combustion air introduced is usually about 5 to 20% greater than the theoretical quantity required.
- Coal and limestone or dolomite in a proportion related to the sulfur content of the combustible solids are fed into the feed chute 1.
- the proportion, based upon the molar ratio of calcium to sulfur, may be within the range of 1:1 up to about 3:1 or higher, depending upon the amount of excess to be carried. An economical and practical proportion may be within the range of about 1.5 to 2.5:1.
- the rotational speed of the cylinder may be varied and, for a cylinder of about 11 feet inside diameter, the rotational speed according to the formula contained herein would be approximately 11 rpm.
- the initial ignition zone might be about 5 feet (1.5m) long, for example.
- a tube bundle 9 is mounted inside the rotating chamber 2 by means of tangential or other supports 10. This is best shown by Figs. 1 and 2.
- 180 U-shaped loops of 2- inch (50.8mm) tubes are shown with a total external area of approximately 5800 square feet (535m 2 ).
- the 180 loops have 360 tube ends and the tubes are arranged in square pitch with 4-inch (101.6mm) spacing.
- the tube bundle 9 consists of what is commonly referred to as U-tubes attached to the far end of the tube sheet 11.
- the tube sheet is attached to channel 12 from which projects the steam outlet pipe 13. Inside of the steam outlet pipe and concentric with it is the water feed pipe 14. In some cases this arrangement is reversed with the steam outlet pipe 13 on the inside and water feed pipe 14 on the outside. Both of these pipes are attached to a conventional rotary seal 15 which permits water feed and discharge of the steam without leakage.
- the water feed pipe 14 passes through a baffle 16 which separates the water feed channel of the U-tubes 17 from the discharge channel 18. In this manner, feed water is circulated through the inside of the U-tubes. Heat is transferred through the U-tubes by hot gases and cascading hot solids flowing over the tubes on the outside, thereby converting some of the circulating water inside the tubes to steam.
- the principal combustion zone 19 wherein the temperature of the gases and solids are maintained at about 1200°C to about 1600°F (645°C to 875°C), depending upon the nature of the combustible feedstock. In this zone, additional volatile materials from the coal or other feedstock and the carbonaceous residue or char are combusted.
- lifters 8 are provided to lift and cascade the hot combustible material mixed with limestone or dolomite through the hot gases and over and between the U-tubes of the tube bundle 9.
- a typical length for the principal combustion zone of this example, with a cylinder outside diameter of 12 feet (3.7m), is about 13 feet 6 inches (4.1m).
- the hot gases and hot solids proceed to the falling temperature combustion zone 20 wherein the gases and hot solids are cooled from the temperature of combustion to about 700°F to 1200°F (370°C to 650°C).
- the falling temperature combustion zone also serves to complete the combustion of the char or carbonaceous residue.
- This zone extends to the end of the heat transfer surface of tube bundle 9 and is equipped with lifters 8 which cascade the solids through the stream of gases and over and between the U-tubes of the tube bundle 9.
- a typical length of the falling temperature combustion zone is about 20 feet 3 inches (6.2m).
- the final zone is the disengaging zone 21 containing no lifters wherein solids are allowed to separate from the gas stream.
- the solids at the point of discharge are essentially ash mixed with spent limestone or dolomite.
- a typical disengaging zone length of about 3 feet 9 inches (1.1 m) is provided.
- the solids pass over discharge weir plate 33 into a breach section and thence into stationary chute 22 for ash disposal.
- Gases are sent to an air preheater and/or a dust collector via the stationary breach section 30, which is sealed with respect to the discharge end plate by a simple conventional rotary seal arrangement 23.
- sulfur oxides formed during combustion react with previously unreacted and/or recirculated limestone or dolomite.
- the sulfur oxides residing with the ash are in stable chemical combination.
- the sulphur trioxides which constitutes about 1 % or less of the total sulfur oxides in the gas stream, react with limestone or dolomite to form calcium sulfate.
- the sulfur dioxide reacts with limestone or dolomite to form calcium sulfite.
- These sulfites are essentially oxidized in the presence of excess air at the operating temperatures to calcium sulfate. By this means, the sulfur oxides are effectively removed from the exhaust gases. Typically, 90% of the total sulfur oxides in the gas stream are removed by the dolomite or limestone.
- a flowsheet is depicted for a system using the present invention to manufacture steam at a gauge pressure of 250 Ib f/in 2 (1.70 x 10 6 N/m 2 ) employing coal as the fuel with an apparatus similar to that shown in Fig. 1.
- Coal containing about 2.5 weight percent sulfur from a storage bin 25 is mixed with limestone supplied from storage bin 26 by conveyor belts 27 and 28, respectively, into the feed chute 1.
- the fuel is mixed with hot, internally recycled solids at about 1500°F (815°C) sufficient in quantity to dry the fuel and bring it up to the ignition temperature.
- the ignited fuel, limestone and recycled solids then progress to a relatively constant temperature combustion zone (termed the principal combustion zone) 19 having a temperature of about 1300°F to 1600°F (700°C to 875°C) where the solids are lifted and cascaded down through the hot gas stream over and between the tube bank or bundle 9, transferring heat along with the hot gases to 40 gallons (150 litres) per minute of make-up boiler feed water circulated through the inside of the tubes. Most of the combustion occurs in this zone and some of the feed water is converted to steam.
- the hot combustion gases and hot solids then pass into the falling temperature combustion zone 20 where the solids continue to be lifted and cascaded through the hot gas stream and over and between the tubes of the tube bundle 9. Some final combustion occurs in this zone and sensible heat in the gases and solids is utilized to generate steam.
- the gases and solids are cooled to about 800°F (420°C) before entering the disengaging zone 21 with no lifters, located at the discharge end of the rotary chamber past the point at which the tubes terminate in the tube bank.
- the solids and gases separate from one another and pass into the breach section of the unit 30.
- the solids which separate from the gases in the disengaging zone 21 pass over an adjustable weir plate 33 into the breach section 30 and thence through a rotary star valve 34 for conveyance pneumatically to an ash silo 35.
- a typical quantity of ash and spent limestone discharge from the rotary boiler would be 450 to 490 pounds (200 to 225 kilogrammes) per hour at 800°F (425°C). In this example, about 25,600 pounds (11,150 kilogrammes) per hour of gases at 800°F (425°C) leave the rotary combustor.
- These gases flow through a discharge duct 36 to a regenerative air preheater 37.
- the mixture of water and steam generated in the tube bundle 9 passes through discharge pipe 13 through rotary seal 15 into steam drum 31 where feed water and steam are separated. Separated water from the steam drum goes to the suction side of a recirculation pump 32 at which point it combines with 40 gpm (150 litres per minute) of fresh boiler feed water which has been deaerated. Feed water enters the tube bundle through a pipe which is concentric with charge 13.
- Figs. 1-3 depict a specific type combustor having hot gases utilized in the combustor for heat exchange with steam generating tubes
- other types of combustors are contemplated by the present invention as it should be understood to a person of ordinary skill in view of this description.
- combustor may be employed where the heat is not transferred within the combustor, rather the hot gases formed by the combustion are conducted out of the combustor to be used elsewhere.
- the apparatus of Fig. 1 may be modified to exclude the tube bundle 9 and conditions of operation of the rotary combustor are essentially the same except that in this arrangement where there is no tube bundle, there is no falling temperature zone.
- the solids pass into a short disengaging section where the solids and gases are separate from one another and the hot gases continue out of the rotary combustor through a hot gas duct.
- the hot gases may then be taken to a boiler for the purpose of making steam, or to another form of heat exchanger to heat or vaporize water or other liquid, or to dry solids such as coal or other material or to any other apparatus which permits the transfer of heat from a gas stream at an inlet temperature of about 1400°F to about 2800°F (760°C to 1540°C).
- the U-bundle 9 may be stationary and thus does not rotate with the rotating cylinder. This may be accomplished by attaching the U-tube bundle to a stationary pedestal.
- a stationary tube bundle may be of the fixed tube-sheet type instead of the U-tube type.
- Such an' arrangement permits support at both ends for a condition where the U-tube bundle would be so long as to make cantilevering impractical.
- the bundle can be arranged to operate in either cocurrent or countercurrent flow with respect to the gases and solids in the rotating cylinder.
- variations of the combustor and boiler arrangements may be made and may be of any conventional type.
- other means may also be provided to remove the hot gases from the combustion chamber to some other type of heat utilization device.
- Fig. 4 depicts another example of a rotary combustion apparatus in accordance with the principles of this invention.
- the following description relates to the use of oily mill scale as a feedstock for the apparatus and the rotary incinerator has been designed to meet the needs of the steel industry for deoiling mill scale and mill scale sludge.
- the rotary combustion apparatus of Fig. 4 includes a cylindrical chamber 41 supported by drum tires 43 and equipped with a conventional variable-speed driving means.
- the chamber 41 is provided with a particulate solids feed opening 44 and discharge outlet 45.
- the chamber 41 is divided into a preheating/ conditioning zone 46, a combustion zone 47 and a solids cooling/air preheat zone 48, and a product quench zone 49.
- Chute 52 delivers the oil containing mill scale and, if necessary, other solid materials into the apparatus.
- a rotating seal 54 seals opening 45 at stationary flue gas stack 65.
- Another seal 53 seals the cool air duct 50 at the opening to stationary air duct 57. These seals are of conventional type. Deoiled mill scale is discharged through chute 56.
- the rotary combustion apparatus 41 is lined with a refractory heat-resistant material of the type suitable to withstand the maximum combustion temperatures therein.
- the recirculation means consisting of at least one helical chute 60 is mounted along the outside wall of chamber 41 and is open-ended at its inlet end 61 and outlet end 62.
- the helical chute curves around chamber 41 in a direction counter to the direction of rotation so that material entering inlet 61 is carried back toward the feed opening 44 until it is discharged into the chamber through outlet 62.
- Lifters 58 are attached to the interior wall of the combustion chamber in the preheating/conditioning, combustion and solids cooling/air preheat zones. The lifters 58 project perpendicularly from interior wall of the rotary combustion apparatus.
- the lifters 58 are oriented parallel to the axis of rotation. There are no lifters for a short distance at the inlet and discharge of the solids cooler/air preheat zone 48. Lifters extend only for a short length in the third quarter of the combustion zone. There are no lifters in the product quench zone.
- Fig. 5 depicts a view of Fig. 4 through the chamber 31 looking toward the feed end. This cross-section is taken approximately through the front end of the solids cooling/air preheat zone 48 and shows the preheated air ducts 51 and exhaust ducts 55.
- the ambient wet feed is delivered to the rotary incinerator 41, particularly the preheating/conditioning zone where the feed is dried and preheated to about 800°F (425°C) by mixing the feed with up to 5 times as much hot recycle deoiled mill scale and by contact with the combustion air preheated to about 950°F (510°C) which enters the apparatus through air duct 51.
- the inlet air enters the apparatus and travels through cool air ducts 50, thence through solids cooler/air preheat zone 48, and thence through air duct 51 which extends to the front end of the combustion zone so that air with the highest oxygen content comes in contact with the mill scale entering the combustion zone with the recycled or spent mill scale.
- any residual oil or carbon in the mill scale is burned out until the resulting flue gases reach the entry opening of the exhaust ducts 55 and ultimately flue gas exhaust flue 65 through which they leave the apparatus.
- the deoiled mill scale leaves the apparatus through discharge chute 56.
- the feed and recycled mill scale are cascaded by lifters in the preheat/conditioning zone to facilitate mixing and to serve as a screen to absorb the radiation from the combustion zone. Oil that is vaporized from the mill scale and mixed with preheated air is ignited by radiation at the entrance of the combustion zone.
- temperature control in the combustion zone is achieved by controlling the amount of fuel added.
- Either gas or oil can serve as an auxiliary fuel.
- the auxiliary fuel is introduced at a point in the preheat/conditioning zone which will induce combustion at the beginning of the combustion zone.
- the hot solids pass over a dam ring 63 and into a splitter box 64 which recycles part of the hot solids through chute 60 to the feed end of the rotary apparatus and sends the rest through a transfer chute into the product or solids cooling/air preheat zone 48.
- a splitter box 64 recycles part of the hot solids through chute 60 to the feed end of the rotary apparatus and sends the rest through a transfer chute into the product or solids cooling/air preheat zone 48.
- the first 2 feet (0.7m) of the solids cooling/air preheat zone 48, there are no lifters 58 to allow preheated air to be separated from the solids and pass through ducts 51 to the feed end of the preheating/ conditioning zone 46.
- Lifters 58 are present in the next 16z feet (5.0m) to insure good heat transfer from the hot solids to the air.
- the air will be heated to 945°F (210°C) and the solids cooled to 555°F (290°C).
- One or more exhaust ducts 55 traverse this zone 48. At the end of this zone, the solids are transferred through a transfer chute into the product quenching zone 49.
- exhaust gas at 1500°F (810°C) and dry deoiled mill scale at about 555°F (290°C) enter the zone. Since there are no lifters in this section, the gas and solids are not in good contact and they can be quenched individually.
- Stationary water sprays 66 mounted on pipes at a high level, quench the exhaust gas from 1500°F (810°C) to below 300°F (145°C).
- Water sprays 67 at a lower level are directed toward the rolling mill scale and cool it from 555°F (290°C) to about 200°F (90°C).
- the cooled solids pour out of the end of the rotary unit into product chute 46 and are directed out of the apparatus. Flue gases leave the apparatus through exhaust flue 65.
- this invention may be utilized for incinerating refinery sludge.
- a rotary incinerator may be specifically designed for refinery sludge which can incinerate the sludge at about 2000°F using coal to supply the additional heat required.
- refinery sludge containing 5% oil, 10% solids, 85% water is incinerated, as assumed in this example for a design basis, only enough coal to supply 1650 Btu per pound (2.8 x 10 6 J/kg) of sludge is required. This amounts to about 12.5% by weight of the sludge.
- a high thermal efficiency is possible with the rotary incinerator because of its ability to recover heat from the exhaust gas.
- an incinerator of the type shown in Fig. 6 is employed.
- the refinery sludge is fed through a pipe 75 and coal is introduced through a chute 76 into the inlet end 77 of the rotary incinerator 78.
- There the sludge and coal are mixed with hot recycled sand which dries the sludge and heats both the water vapor and dried solids to about 1200°F (650°C).
- Preheated air is also introduced into the front or inlet end of the incinerator through preheated air ducts 79 and burning takes place at temperatures of about 1200°F (650°C) to about 2000°F (1100°C).
- Enough space is provided in the combustion zone 80 to provide 2- second residence time at about 2000°F (1100°C).
- the cascading of the hot solids in the combustion zone 80 as hereinabove described in connection with the other examples insures complete combustion of the sludge.
- heat is recovered from the hot combustion gases by passing them countercurrent to cascading solids in the solids reheat zone.
- the combustion gases After being cooled to about 1210°F (655°C), the combustion gases exit through an exhaust duct 83 running through the air preheat zone 82.
- Water sprays 84 cool the exhaust gas to about 300°F (150°C) before it passes through exhaust flue 85 and thence to a bag house and an ID fan (not shown).
- Air enters the air preheat zone 82 of the incinerator through air duct 86, and moves countercurrent to cascading hot solids from the solids reheat zone 81.
- Preheated air at about 1600°F (870°C) is conducted to the front end of the incinerator through preheated air ducts 79.
- Pressure drop through the incinerator is quite low, on the order of about 1 or 2-inch (25 or 50mm) WC.
- the pressure at the front end of the incinerator is maintained slightly below atmospheric pressure.
- the front of the incinerator can remain open for easy feeding, inspection and temperature measurement.
- Make up heat transfer solids, such as sand, are added at the front end of the incinerator.
- the fine portion of the residue or ash from the refinery sludge will exit with the combustion gas through exhaust flue 85 and can be captured in a bag house (not shown). Any coarse residue can serve as a heat transfer solid until it is discharged at the end of the air preheat zone of the rotary incinerator.
- the incinerator which may be employed in this example is a rotary unit of the type contemplated by this invention. Basically, it is a cylindrical unit having an outer diameter of about 12 feet 6 inches (3.8mm) and is about 60 feet (18m) long.
- the combustion zone 80 is lined with a castable refractory 87 which is shaped to form lifters 88 and is approximately 25 feet (8.0m) in length.
- a spiral chute 89 recycles heat transfer solids from the end of the combustion zone 80 to the front of the combustion zone to bring the feed up to ignition temperature.
- a spiral chute 91 may be employed to conduct the hot solids from the front of the solids reheat zone 81 to the air preheat zone 82. This spiral chute is fashioned so that it is rotating with the axis of rotation of the rotary unit so that the solids may be transferred to the air preheat zone.
- a spiral chute 93 may be employed to conduct solids from the discharge end of the air preheat zone 82 into the downstream end of the solids reheat zone 81.
- Combustion gas which is cooled to about 1210°F (655°C) passes into a 4-foot (1.2m) diameter exhaust duct 83 in the center of the air preheat section 82.
- the combustion gases are cooled to about 300°F (150°C) by water sprays 84 within the ducting before entering through exhaust flue 85 and thence to the bag house (not shown).
- the air preheat zone is separated from the solids preheat zone by a bulk head 92. Ducts for the preheated air 79 extend from the bulk head 92 to the front of the combustion zone 80.
- the air preheat zone is lined with refractory and is about an 8-foot (2.5 m) section containing lifters. Complete combustion is achieved within the incinerator and no after burner is required.
- an incinerator similar to that described in connection with Figs. 4 and 5 above consisting essentially of four zones, namely, the feed preheating/conditioning zone, combustion zone, solids cooling/air preheat zone and product quench zone.
- Spent foundry sand may be contaminated with organic binders which cause it to be classified as a hazardous material. If the organics are burned out and metallic particles recovered by screening, the spent sand can be rendered nontoxic and may have a positive value as a land fill cover or similar use.
- the organic materials may be burned within the rotary apparatus and an after burner is not required. Minimum auxiliary fuel may be required because much of the sensible heat in the incinerated sand is recovered by preheating the combustion air.
- a rotary incinerator having a design similar to that described in Figs. 4-5 above.
- the unit is essentially a drum having an overall length of about 23-feet 6-inches (7.2m) and an inside diameter of about 5-feet (1.5m).
- the drum consists of three individual compartments separated by dividing walls, i.e., a feed preheat and combustion compartment, product cooler compartment and a quench compartment.
- the fresh feed is mixed with recycle sand heated to about 1300°F (700°C).
- preheated air from the solids cooling/air preheat zone is introduced by external ducts and a flame is developed as the decomposition products from the organic binders in the sand, and in the auxiliary fuel, which is added at the front end of the incinerator, are burned.
- a 3 foot (0.9m) section at the front of the combustion zone the cascading of sand is suppressed by shortening the lifters to allow for flame development and a high combustion rate.
- solids cooling/air preheat zone the product is cooled from 1300°F (700°C) to about 700°F (370°C) by cascading it through the incoming air. This preheats the air from ambient conditions to about 1200°F (650°C). At the end of this compartment the sand passes over a dam ring which maintains the proper loading and then into a spiral chute which transfers the sand to the product quench zone.
- the product quench zone there is a set of stationary water sprays near the top of the compartment to cool the exhaust gases to about 250°F (120°C) in a manner similar to that described above in connection with the mill scale deoiling example. Another set of stationary water sprays is directed onto the sand to cool it from about 700°F (370°C) to about 210°F (100°C) after which the sand flows into a product recovery area in a manner similar to that described above.
- the rotating chambers described herein are cylindrical, the principles of this invention do not require any specific shape and will, in fact, operate satisfactorily with any chamber having a regularly shaped cross-section area as, for example, a regular prism or a slender cone.
- the base of the cone might be at the discharge end of the combustion section for example, for cocurrent air flow in that section. This would provide a means for controlling the relative gas velocity by controlling the cross- sectional area. In this manner, the enlarged cross-section would result in a decreased gas velocity leading to greater settling of any entrained solids from the gas stream.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Thermal Sciences (AREA)
- Fluidized-Bed Combustion And Resonant Combustion (AREA)
Claims (14)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT84303312T ATE56518T1 (de) | 1983-05-17 | 1984-05-16 | Verfahren und vorrichtung zur verbrennung von materialien. |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US495423 | 1983-05-17 | ||
US06/495,423 US4477331A (en) | 1983-05-17 | 1983-05-17 | Method for retorting particulate solids having recoverable volatile constituents in a rotating horizontal chamber |
US06/518,219 US4583468A (en) | 1983-07-28 | 1983-07-28 | Method and apparatus for combustion of diverse materials and heat utilization |
US518219 | 1990-05-03 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0126619A2 EP0126619A2 (fr) | 1984-11-28 |
EP0126619A3 EP0126619A3 (en) | 1985-08-14 |
EP0126619B1 true EP0126619B1 (fr) | 1990-09-12 |
Family
ID=27051756
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19840303312 Expired EP0126619B1 (fr) | 1983-05-17 | 1984-05-16 | Procédé et dispositif de combustion des matériaux |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0126619B1 (fr) |
DE (1) | DE3483173D1 (fr) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3444073A1 (de) * | 1984-12-03 | 1986-06-05 | Dyckerhoff Engineering GmbH, 6200 Wiesbaden | Verfahren und anlage zum verbrennen von abfaellen wie haus-, industrie- und sondermuell |
GB2198519B (en) * | 1986-12-04 | 1990-10-03 | John Hall | Improved solid fuel burner |
ATE70610T1 (de) * | 1988-06-13 | 1992-01-15 | John Hall | Brenner fuer festen brennstoff. |
BR0111730B1 (pt) * | 2000-06-14 | 2011-02-22 | aparelho e processo para tratar material residual hidrocarboneto. | |
TR200401596A2 (tr) * | 2004-06-30 | 2006-01-23 | N�Zam� �Zcan Al� | "Tam otomatik sürekli kömür beslemeli, geliştirilmiş özel kuru desülfürizasyon sistemli ve iki yanma odalı, borusuz özel tasarımlı çift yakıtlı dumansız kazan" |
WO2013101658A1 (fr) * | 2011-12-29 | 2013-07-04 | Eastman Chemical Company | Procédé et appareil de traitement de bois utilisant un système de soulèvement de fardeau |
CN113137607B (zh) * | 2021-04-25 | 2022-01-11 | 浙江宏电环保装备有限公司 | 一种废气颗粒处理装置及其使用方法 |
CN118009327B (zh) * | 2024-04-01 | 2024-10-01 | 磁县鑫盛煤化工有限公司 | 一种脱硫废液焚烧设备及脱硫废液处理工艺 |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB372429A (en) * | 1931-02-16 | 1932-05-12 | William Parker | Improvements relating to apparatus for firing boilers |
FR1445141A (fr) * | 1965-08-20 | 1966-07-08 | Buckau Wolf Maschf R | Tambour rotatif pour l'incinération des déchets industriels |
SE325092B (fr) * | 1965-09-15 | 1970-06-22 | Landsverk Ab | |
GB1144403A (en) * | 1966-02-07 | 1969-03-05 | Matteini Silvano | Improvements in or relating to incinerators |
FR2398261A1 (fr) * | 1977-07-20 | 1979-02-16 | Oconnor Chadwell | Four rotatif dont le tambour est constitue d'un ecran d'eau, destine a l'incineration de dechets |
US4205630A (en) * | 1978-11-15 | 1980-06-03 | Combustion Engineering, Inc. | Steam air preheater for maintaining the flue gas temperature entering dust collection equipment |
-
1984
- 1984-05-16 DE DE8484303312T patent/DE3483173D1/de not_active Expired - Fee Related
- 1984-05-16 EP EP19840303312 patent/EP0126619B1/fr not_active Expired
Also Published As
Publication number | Publication date |
---|---|
DE3483173D1 (de) | 1990-10-18 |
EP0126619A2 (fr) | 1984-11-28 |
EP0126619A3 (en) | 1985-08-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4583468A (en) | Method and apparatus for combustion of diverse materials and heat utilization | |
US4724777A (en) | Apparatus for combustion of diverse materials and heat utilization | |
AU2005296029B2 (en) | Apparatus for heat treatment of particulate materials | |
US4253409A (en) | Coal burning arrangement | |
AU2005295110B2 (en) | Method of enhancing the quality of high-moisture materials using system heat sources | |
US3804606A (en) | Apparatus and method for desulfurizing and completely gasifying coal | |
US6210154B1 (en) | Treatment of exhaust gases from kilns | |
CA2133638C (fr) | Desulfuration de combustibles carbonaces | |
JPS5911545B2 (ja) | ポルトランドセメント製造及び廃棄物の利用 | |
CN107721112B (zh) | 城市污泥干化热解气化自持焚烧系统 | |
JPS61184321A (ja) | 家庭ごみ、工業ごみ、特殊ごみのような廃棄物を燃焼させるための方法と装置 | |
US5103743A (en) | Method and apparatus for drying solid material | |
KR102405860B1 (ko) | 슬러지의 처리 방법 및 시멘트 제조 시스템 | |
KR100202780B1 (ko) | 벌크재료의 제조장치 | |
WO1999023431A1 (fr) | Four de gazeification et de chauffage a lit fluidise | |
US5237963A (en) | System and method for two-stage combustion in a fluidized bed reactor | |
EP0126619B1 (fr) | Procédé et dispositif de combustion des matériaux | |
EP0577759B1 (fr) | Four a foyer multiple a flux concourant pour l'incineration d'un gateau de filtration d'une boue d'egout | |
CN106322404A (zh) | 基于直吹式高温烟气干化污泥与煤流化悬浮耦合燃烧系统 | |
US4949655A (en) | Process for the utilization of powdered solid waste | |
GB2074890A (en) | Fluidized Bed Combustors | |
JPS6089614A (ja) | 発熱量の少ない有害・廃棄物、特に塵芥を燃焼によつて有害物質なしに除去する方法と装置 | |
US5394811A (en) | Process for drying a water-containing fuel in direct contact with a hot granular solid residue | |
Dangtran et al. | A comparison of fluid bed and multiple hearth biosolids incineration | |
RU2690553C1 (ru) | Тепловой агрегат для совместного получения цементного клинкера, сернистого газа, тепловой и электроэнергии |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
|
17P | Request for examination filed |
Effective date: 19860123 |
|
17Q | First examination report despatched |
Effective date: 19861016 |
|
D17Q | First examination report despatched (deleted) | ||
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
|
REF | Corresponds to: |
Ref document number: 56518 Country of ref document: AT Date of ref document: 19900915 Kind code of ref document: T |
|
REF | Corresponds to: |
Ref document number: 3483173 Country of ref document: DE Date of ref document: 19901018 |
|
ET | Fr: translation filed | ||
ITF | It: translation for a ep patent filed | ||
ITTA | It: last paid annual fee | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
EPTA | Lu: last paid annual fee | ||
EAL | Se: european patent in force in sweden |
Ref document number: 84303312.7 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 19950505 Year of fee payment: 12 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 19950510 Year of fee payment: 12 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 19950511 Year of fee payment: 12 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: AT Payment date: 19950512 Year of fee payment: 12 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: CH Payment date: 19950516 Year of fee payment: 12 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: SE Payment date: 19950517 Year of fee payment: 12 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: NL Payment date: 19950531 Year of fee payment: 12 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: LU Payment date: 19950601 Year of fee payment: 12 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: BE Payment date: 19950712 Year of fee payment: 12 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LU Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 19960516 Ref country code: GB Effective date: 19960516 Ref country code: AT Effective date: 19960516 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Effective date: 19960517 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LI Effective date: 19960531 Ref country code: CH Effective date: 19960531 Ref country code: BE Effective date: 19960531 |
|
BERE | Be: lapsed |
Owner name: PEDCO INC. Effective date: 19960531 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Effective date: 19961201 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 19960516 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Effective date: 19970131 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Effective date: 19970201 |
|
EUG | Se: european patent has lapsed |
Ref document number: 84303312.7 |
|
NLV4 | Nl: lapsed or anulled due to non-payment of the annual fee |
Effective date: 19961201 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |