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
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
  • F23J15/00—Arrangements of devices for treating smoke or fumes
  • F23J15/06—Arrangements of devices for treating smoke or fumes of coolers
• • 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
  • F23G5/008—Incineration of waste; Incinerator constructions; Details, accessories or control therefor adapted for burning two or more kinds, e.g. liquid and solid, of waste being fed through separate inlets
• • 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
  • F23G5/08—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having supplementary heating
  • F23G5/14—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having supplementary heating including secondary combustion
  • F23G5/16—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having supplementary heating including secondary combustion in a separate combustion chamber
• • 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
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
  • F23G5/24—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having a vertical, substantially cylindrical, combustion chamber
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
  • F23G7/008—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals for liquid waste
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
  • F23G7/14—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of contaminated soil, e.g. by oil
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
  • F23J15/00—Arrangements of devices for treating smoke or fumes
  • F23J15/006—Layout of treatment plant
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
  • F23J15/00—Arrangements of devices for treating smoke or fumes
  • F23J15/02—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material
  • F23J15/022—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material for removing solid particulate material from the gasflow
  • F23J15/025—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material for removing solid particulate material from the gasflow using filters
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2201/00—Pretreatment
  • F23G2201/10—Drying by heat
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2202/00—Combustion
  • F23G2202/10—Combustion in two or more stages
  • F23G2202/102—Combustion in two or more stages with supplementary heating
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2202/00—Combustion
  • F23G2202/10—Combustion in two or more stages
  • F23G2202/103—Combustion in two or more stages in separate chambers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2204/00—Supplementary heating arrangements
  • F23G2204/20—Supplementary heating arrangements using electric energy
  • F23G2204/203—Microwave
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2900/00—Special features of, or arrangements for incinerators
  • F23G2900/52002—Rotary drum furnaces with counter-current flows of waste and gas
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
  • F23J2217/00—Intercepting solids
  • F23J2217/10—Intercepting solids by filters
  • F23J2217/101—Baghouse type
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
  • F23J2219/00—Treatment devices
  • F23J2219/60—Sorption with dry devices, e.g. beds

Definitions

• the present invention relates to a method and an apparatus for using hazardous waste to form non-hazardous aggregate by thermally induced oxidation.
• a process for converting hazardous waste to non-hazardous aggregate includes the step of providing a source of solid waste material comprised of large solid waste and waste fines. These materials are separated and the large solid waste is introduced to a rotary kiln having an input portion, a combustion portion and an exit portion. Operating conditions in the kiln are controlled such that large solid waste is combusted to form solid particulate primary aggregate, clinker and gaseous combustion by-products. A major portion of volatile combustibles in the large solid wastes are volatilized in the input portion of the kiln.
• the gaseous combustion by-products from the kiln are passed therefrom by means of an induced draft.
• the waste fines separated from the solid waste material are introduced to an oxidizing means along with combustible material. Combustion in the oxidizing means is induced to convert the waste fines into non-combustible fines, molten slag and waste gas.
• the temperature in the oxidizing means is controlled, preferably, in the range of from 1800° to 3000°F.
• the non- combustible fines and waste gas from the oxidizing means are passed therefrom by means of an induced draft.
• the non- combustible fines, the gaseous combustion by-products and the waste gas are cooled and the non-combustible fines are separated from the combustion products and waste gae.
• the solid particulate primary aggregate and non-combustible fines are re-introduced into the oxidizing means. Heat from the oxidizing means is impinged on the non-combustible fines and the primary aggregate to form molten slag.
• the molten slag is cooled to form the non-hazardous slagged aggregate. It is preferred that when the primary aggregate and the non- combustible fines are introduced into the oxidizing means, they are introduced into the oxidizing means in discrete batch portions.
• those materials are introduced into the oxidizer means, they are introduced in the form of a pile where heat from the oxidizing means is impinged on the surface of the pile. It is further preferred that the rotary kiln operates at an average internal temperature in the range of from 1600°F to 2300°F.
• a preferred apparatus for carrying out the method of the present invention to convert hazardous waste into a non-hazardous aggregate includes a rotary kiln having an entry portion and an exit end. Oxidizing means are adjacent the entry portion of the kiln. There is also provided a source of solid waste material with the solid waste material comprising large solid waste and waste fines. Means for separating the large solid waste from the waste fines are included as are means for introducing the large solid waste to the entry portion of the rotary kiln. The device further includes means for inducing combustion in the kiln to convert the large solid waste to solid particulate primary aggregate, clinker, volatile gases and gaseous combustion by-products. Means are used to separate the clinker from the solid particulate primary aggregate.
• the device further includes means for passing the gaseous combustion by-products from the kiln and from the oxidizing means. Means are included for inducing combustion in the oxidizing means to convert the waste fines, the volatile gases and the gaseous combustion by-products into non-combustible fines, molten slag and waste gas. Cooling means cool the non-combustible fines in the waste gas and separating means separate the non-combustible fines and the waste gas. The device further includes means for introducing the solid particulate primary aggregate and re-introducing the solid non-combustible fines to the molten slag to form a substantially molten mixture.
• the device includes means for cooling the substantially molten mixture to form the non-hazardous slagged aggregate.
• the oxidizing means comprise a plurality of refractory-lined vessels in flow communication with the entry portion of the rotary kiln.
• Fig. 1 is a schematic representation of one embod ⁇ iment of the present invention.
• Fig. 2 is a schematic partial cross-section of the oxidizing means of the embodiment of Fig. 1.
• Fig. 3 is a schematic representation of an embodi ⁇ ment for accumulating particulate material that is introduced into the oxidizing means of the embodiments of Figs. 1 and 2. DESCRIPTION OF THE PREFERRED EMBODIMENT
• FIG. 1 The embodiment of the present invention is sche ⁇ matically depicted in Fig. 1.
• the present invention is an apparatus for convert ⁇ ing hazardous waste into non-hazardous aggregate and a pro ⁇ cess of operating apparatus for carrying out that function.
• a rotary kiln having an entry portion and an exit portion.
• the rotary kiln 10 includes an entry portion 12 and an exit portion 14.
• the com ⁇ bustion portion 16 Located between the entry and exit portions of the rotary kiln, is the com ⁇ bustion portion 16. While in the embodiment depicted, the boundaries of the various portions are co-terminal, the three portions of the rotary kiln are merely illustrative and can overlap. That is to say some combustion may take place in the entry portion 12 or the exit portion 14, however, combustion takes place primarily in the combustion portion 16 of the rotary kiln 10.
• the kiln depicted schematically in Fig. 1 is a standard counter current rotary kiln constructed for the treatment of limestone or oyster shell to form lime. It is comprised of an external metal shell that is lined with re ⁇ fractory brick. The composition of the refractory brick is determined by the operating temperatures and the materials passed through the rotary kiln. In the present embodiment where the rotary kiln is designed to operate at a temperature in the range of from 1600° to 2300°F, a refractory brick consisting of 70% alumina a product of the National Refractory Company of Oakland, California has been used without premature refractory deterioration.
• the rotary kiln is supported on conventional bearing supports (not shown) and driven at. rotational speeds in the range of 1 to 75 RPH by conventional kiln drive means (not shown . ) .
• the rotary kiln 10 includes cooling chambers 18 on the exit portion of the kiln.
• the cooling chambers receive the solid material through ports communicating into the rotary kiln.
• the chambers receive the larger solid material which is transmitted by rotation to an exit chute 20 where the solid material issuing from the rotary kiln exits therefrom.
• a source of fuel 22 is also associated with the rotary kiln 10 as well as a source of air 24 to support combustion within the rotary kiln 10.
• the fuel that can be used can be combustible liquid or gas, including combustible waste liquids, combustible liquid fuel or combustible natural gas. Oxygen, or water in combination are used to control temperatures and combustion.
• the air fuel mixture is introduced to- the rotary kiln 10 at the exit portion 14 with gases in the kiln 10 passing toward the entry portion 12 counter-current to the larger solids being transported by rotation of the kiln toward the exit portion 14.
• the smaller particles are entrained in the gases passing through the kiln and are thus separated from the larger solids and transported from the kiln.
• the apparatus includes oxidizing means adjacent the entry portion of the kiln.
• the apparatus includes a first oxi ⁇ dizer 26.
• the first oxidizer 26 is adjacent to the entry portion 12 of the rotary kiln.
• the oxidizer 26 is in flow communication with the entry portion 12 of the rotary kiln 10 and receives volatile gas driven off the material introduced to the rotary kiln as well as the combustion by-products from the combustion taking place in the rotary kiln.
• a source of waste material introduces material to the entry portion 12 of the kiln 10, where the counter-current gas flow effects a separation of the larger particles (solid waste material) and the smaller particles (waste fines).
• the solid waste material is comprised of large solid waste and waste fines.
• large solid waste is waste having a particle size greater than about 50 microns whereas waste fines are defined as any material hav ⁇ ing a particle size less than 50 microns.
• the appara ⁇ tus is operable with materials separated to a different size, it is the purpose of the separation to provide material to the first oxidizer 26 than can be readily oxidized or melted in its physical state with the larger material being introduced to the kiln to be broken down during its transit through the rotary kiln to either incombustible material, volatile gas or combustion by-products.
• the apparatus includes a passive conveyor 30 which receives material from the waste source 28 and introduces the waste derived fuel into the entry portion 12 of the rotary kiln 10. Classifying of the large solid waste from the waste fines occurs throughout the rotary kiln 10. It should also be noted that the solid waste could also be separated by size prior to introduction into the kiln and the waste fines can then be directly introduced into the oxidizing means.
• the apparatus includes means for inducing combustion in the kiln to convert the large solid waste to solid particulate primary aggregate, clinker, volatile gases and gaseous combustion by-products.
• the combustion inducing means include the fuel source 22, the oxygen source 24 and the rotary kiln 10.
• the operating conditions in the kiln are such that the large solid waste is converted primarily to particulate primary aggregate, volatile gases and gaseous combustion by-products with the amount of clinker produced by the rotary kiln being minimal.
• Operation of the rotary kiln 10 passes the solids to the exit portion 14 of the rotary kiln through the cooling chambers 18 to the exit chute 20.
• the solid material exiting the exit chute 20 is sent to kiln classifer 34.
• Classifer 34 may be any conventional mechanism for separating large solid particles from fine solid particles.
• any solid material having a diameter in excess of 3/8 inches is classified as clinker with anything less than that being primary aggregate.
• the clinker and particulate is passed over a ' magnetic spearator 32.
• the primary aggregate is passed over another magnetic separator 32A.
• the ferrous metals are removed and sent to a metal bin for sale as scrap steel.
• the means for inducing combustion in the oxidizer means comprise the oxidizer fuel source 36 and oxygen source.
• the oxidizer 26 receives waste fines and volatile gases from the rotary kiln 10 which may or may not be combustible, combustion by-products from rotary kiln 10, fuel from fuel source 36 and oxygen from oxygen source 38.
• first oxidizer 26 operates at a temperature in the range of from 1800° to 3000°F. In an oxidizing environment, combustible materials within the first oxidizer 26 are converted to waste gas and non-combustible fines. The non-combustible fines may or may not be melted depending on their composition.
• a portion of the non-combustible fines are melted and collect at the bottom of first oxidizer 26 in the form of liquid slag 40.
• the liquid slag is shown being removed from the apparatus by means of slag port 42, such a slag port may optionally be placed along the bottom of the first oxidizer 26.
• the slag port 42 has associated therewith a burner 44 disposed to keep the materials adjacent the slag port 42 molten.
• the apparatus may optionally include a burner directed into first oxidizer 26 for the purpose of raising the temperature at various locations within the oxidizer 26.
• first oxidizer is a refractory-lined vessel in flow communication with the entry portion 12 of the rotary kiln 10.
• the first oxidizer in the present embodiment has a square cross section and includes a metal shell 46 having an interior refractory lining.
• the refractory lining in the embodiment depicted includes refractory brick 48 and a monolithic refractory lining 50.
• the refractory brick is 70% alumina made by the National Refractory Company of Oakland, California.
• the monolithic lining is JadePak made by the A.P.
• the refractory brick at the bottom of the first oxidizer 26 is significantly thicker than the refractory brick in the wall section of first oxidizer 26. This is the result of the operating temperatures at that portion of the oxidizer caused by the flowing liquid slag 40 transmitting heat from the hot gases passing through the interior portion 52 of the oxidizer 26.
• Another preferred embodiment of the first oxidizer would have a water cooled ceiling, water cooled metal walls and a refractory floor. Such a construction allows higher operating temperatures.
• the hot gases are turned 90 degrees toward conduit 54 connecting the first oxidizer 26 with a second oxidizer 56.
• the construction of the second oxidizer 56 is similar in some respects to that of the first oxidizer 26. In the embodiment shown, however, the second oxidizer 26 is cylindrical with an interior 58 that is also cylindrical.
• the hot gases and particulate fines pass from the first oxidizer 26 through the conduit 54 to the second oxidizer 56.
• the construction of the conduit 54 and the second oxidizer 26 is similar to that of the depicted embodiment of the first oxidizer in that they are refractory lined steel structures.
• the refractory used in the conduit 54 is JadePak and the refractory used in the second oxidizer 56 is JadePak.
• second oxidizer 56 Similar to first oxidizer 26, second oxidizer 56 also includes multiple layers of refractory brick at the bottom portion thereof. The function of this multiple layer of refractory has been discussed above.
• liquids are injected into second oxidizer 56 as here embodied through liquid inlet 60.
• the source of liquid for liquid inlet 60 in the present embodiment comprises a sump system (not shown) surrounding the entire apparatus. Any liquid including waste derived fuels, rain water or contaminated rain water are collected in a sump system and injected into the second oxidizer 56 through liquid inlet 60.
• the overall apparatus has means for using waste derived fuel and contaminated water surrounding the apparatus within the apparatus itself.
• One skilled in the art to which the invention pertains can readily design a drainage and sump system to be operable with the present invention without specific disclosure of such a system.
• a means for cooling the non-combustible fines and waste gas there is provided.
• quench vessel 62 includes a water inlet 64.
• the water inlet 64 has therein a nozzle not sho#n that introduces water and air at greater than sonic velocities.
• the spray nozzle is a "sonic" model SC CNR-03-F-02 made by Sonic of New Jersey.
• a source of water 66 In flow communication with the water inlet is a source of water 66.
• the water source 66 is fed water that does not include waste.
• Fig. 1 schematically, there is a source of caustic material which is in flow communication with a a spray nozzle 70 that introduces a caustic liquid as a spray into the dry spray reactor vessel 62. It is the function of the spray injection of caustic material to neutralize any acid within the waste gas.
• the apparatus includes means for passing the gaseous combustion by-products from the kiln and the waste gas from the oxidizer means.
• a connecter 72 in flow communication between the second oxidizer 56 and the dry spray reactor 62.
• the connector has a construction similar to that of oxidizer number 2, namely, it is a refractory lined metal shell.
• the dry spray reactor 62 is also a refractory lined metal vessel.
• the system is run at less than an atmospheric pressure.
• any leakage at the interface between portions of the apparatus is not detrimental to the performance of the apparatus so long as the amount of leakage is not so excessive to detrimentally effect the combustion of materials within the oxidizers. This requirement is not as critical in other portions of the device operating at lower temperatures.
• the apparatus includes means for separating the non-combustible fines and the waste gas.
• the apparatus includes two filter systems operat ⁇ ing in parallel, each including a filter 74 and a fan 76.
• the waste gas and particulate fines are introduced to the filter at a temperature preferably more than 350°F. and less than 400°F so that conventional baghouse filters may be used.
• Operation of the present embodiment has determined that conventional teflon filter elements can be used in connection with this operation.
• the waste gas is separated from the non- combustible particulate fines and the waste gas is then passed by monitoring means 78 that monitor the composition and temperature of the waste gas.
• the waste gas is then passed into the atmosphere through stack 80.
• the fans 76 induce a draft throughout the entire apparatus drawing the volatile gases and combustion by-products from the rotary kiln.
• the combustion by-products from the rotary kiln, the combustion by-products from the oxidizers and all the gases passing through the system pass through the fan 76 such that the entire apparatus runs at sub-atmospheric pressure.
• the particulate fines accumulated in the filter 74 are passed by means of a pump means 82 to the accumulator 84.
• the primary aggregate is passed through a pump 86 into the accumulator 84.
• the preferred embodiment of the accumulator 84 is depicted in Fig. 3.
• the apparatus includes means of introducing the non-combustible particulate fines and the primary aggregate into the oxidizer means, specifically, the second oxidizer 56.
• the accumulator 84 includes a first inlet 88 disposed to receive particulate fines from pump 82.
• the accumulator 84 further includes a second inlet 90 disposed to receive primary aggregate through pump 86.
• a first sensor 92 for detecting the desired maximum level of particulate material within the accumulator 84.
• a second sensor 94 detects the level of particulate material within the accumulator 84 and by means of a sensor control mechanism operates a valve 98 by means of valve control means 100.
• the inlets 88 and 90 introduce particulate material into the accumulator 84 where it accumulates up to a predetermined level such that upper sensor 92 is activated, it through control sensor control means 96 and valve control 100 opens the valve 98, thereby allowing particulate material to pass through the conduit 102 into the second oxidizer 56 as depicted in Fig. 2.
• the sensor control and the valve control 100 close the valve 98, thereby interrupting flow of particulate material through the conduit 102.
• conduit 102 is shown introducing solid particulate material into the second oxidizer 56
• solid par ⁇ ticulate material may also be introduced into first oxidizer 26 or both the first and second oxidizers.
• the solid particulate material introduced to the second oxidizer through conduit 102 falls into the central portion 58 of the second oxidizer 56 and forms a pile on the bottom. Heat from the gas passing through the second oxidizer 56 is impinged on the surface of the pile of particulate material melting the portion of the particulate material that has a melting point below that of the gas being impinged on the surface.
• the material flows from the pile 104 entraining any particulate material that is not melted therein and joins the molten slag 40 to flow from the slag port 42.
• the apparatus includes means for cooling the substantially molten mixture to form the non-hazardous aggregate.
• the device includes cool ⁇ ng means 106 depicted schematically in Fig. 1.
• the cooling means simply comprise water into which the substantially molten mixture is dumped. The cooling means extract the heat from the molten mixture and form the non-hazardous aggregate.
• the first step of the process is providing a ' source of solid waste material that is comprised of large solid waste and waste fines.
• the waste is transported to the apparatus in various forms.
• the waste can be in the form of a particulate solid such as contaminated top soil, contaminated construction rubble, semi-solid sludge from a sewage treatment operation, metal drums of liquid waste, fiber drums (commonly referred to as lab packs) containing liquids or solids.
• the waste material is a liquid bearing sludge
• the waste is first passed over a shaker screen where the liquid is removed and introduced into the apparatus of the present invention separately from the solid residue.
• the drums are shredded and introduced into the rotary kiln as part of the large solid waste, threby eliminating the need for cleaning or inspection of the drums. It may also be necessary to shred the input materials several times to obtain an input material that is efficiently consumed in the process.
• it is advantageous to know the certain characteristics of the input materials so that the feed rate of the waste materials and other input materials introduced to the apparatus can be controlled to obtain 'he desired operating conditions.
• the waste material arrives with a description that would include a BTU and moisture content. It may also be necessary, however, to check the BTU content and other characteristics of the input materials so that the operation of the apparatus can be facilitated. It should be noted that while a load of waste material may have an overall BTU content of one value, many times the waste is non-homogenous and therefore the operation of the apparatus and the control of the process requires some intervention to prevent the operating parameters from deviating from that necessary to completely oxidize the combustible components of the waste and produce the desired non-hazardous aggregates. In addition to the BTU and moisture content, it is advantageous to also know the acid content, the amount of ash and the halogen concentration.
• the acid content of the waste provides the operator with means to assess how much caustic would be consumed in the process which impacts both the operation of the process and its economics.
• the amount of ash in the waste determines how much aggregate will be produced.
• the halogen content affects the operations of the process and preferably should be in the range of from 10 to 15%.
• the process in ⁇ cludes the step of separating the large solid waste from the fines, as disclosed above, this separation may occur in the rotary kiln 10 or may be accomplished by simply directing the approprately sized waste to different positions of the apparatus. For example, if the waste fines are contaminated top soil, they can be directly introduced to the oxidizing means.
• the process in ⁇ cludes the step of introducing the large solid waste to a rotary kiln having an input portion, a combustion portion and an exit portion.
• the operating conditions in the kiln are controlled such that the large solid waste is combusted to form solid particulate primary aggregate, clinker and gaseous combustion by-products with a major portion of volatile combustibles in the large solid waste being volatilized in the input portion of the kiln.
• the rotary kiln is operated at an average internal temperature in the range of from about 1600° to 2300°F.
• the large solid waste is introduced into the rotary kiln at a rate depending on its BTU content but normally at a rate of approximately 20 tons per hour.
• the kiln is rotated at a speed in the range of from 1 to 75 RPH such that the total residence time of solid material exiting the kiln at the exit portion 14 is in the range of from about 90 to 120 minutes.
• the rotary kiln pro ⁇ considers a solid output consisting predominantly of solid par ⁇ ticulate primary aggregate with a minor amount of material that can be classified as clinkers.
• clinkers are normally large sized solids, for example, construction bricks that pass through the rotary kiln unreacted or agglomerations of low melting point material that have melted and agglomerated at the relatively low temperatures in the rotary kiln.
• the operating condi ⁇ tions of the rotary kiln are controlled to facilitate two conditions.
• the primary aggregate is recirculated into ⁇ .he process to be melted and introduced to the molten slag in the oxidizing means. Inasmuch as the slag is formed into the non-hazardous aggregate, it is desired to convert as much of the processed materials into that form as possible.
• the material forming the clinker output from the kiln is tested to determine if it has hazardous material that can be leached therefrom. Any material having leachable hazardous material is reintroduced into the rotary kiln at the input portion. Operation of the present apparatus and process results in a very minor portion of the output from the rotary kiln being classified as clinker material.
• the second goal in operating the rotary kiln is to volatilize a major portion of the volatile combustibles in the input portion of the rotary kiln. This reduces the BTU content of the solid material passing through the rotary kiln into the combustion portion 16 of the rotary kiln. If the BTU content of the solid portion reaching the combustion portion 16 of the rotary kiln 10 is excessive, uncontrolled combustion can occur within the combustion portion of the kiln.
• the operating conditions of the rotary kiln should include a temperature at the input portion high enough to volatilize most of the volatile components in the large solid waste being introduced to the kiln.
• Classifier 34 may be any conventional mechanism for separating large solid particles from fine solid particles. As here embodied, any solid material having a diameter in excess of 3/8 inches is classified as clinker with anything less than that being primary aggregate. The clinker and particulate is passed over a magnetic separator 32. The primary aggregate is passed over another magnetic separator 32A. The ferrous metals are removed and sent to a metal bin for sale as scrap steel.
• the gaseous com ⁇ bustion by-products from the kiln are passed therefrom by means of an induced draft.
• the fan 76 maintains the entire apparatus at a sub-atmospheric pressure and draw the gas from the rotary kiln as well as the oxi ⁇ dizers through the entire system.
• the process in ⁇ cludes introducing waste fines to oxidizing means.
• waste fines from rotary kiln 10 are entrained in the gas stream and carried into the oxidizer 26.
• combustible material is introduced into the oxidizing means.
• a source of liquid fuel 36 associated with the first oxidizer 26.
• the input of fuel, waste fines, volatile gases from the solid waste material in the kiln and oxygen injection are all used to control the temperature in the ⁇ irst oxidizer which should range from about 1800° to 3000°F.
• the temperature is determined by the BTU content of the input materials, including any auxiliary fuel that is introduced.
• the auxiliary fuel from the fuel source 36 comprises combustible liquid waste material.
• the combustible liquid waste material comprise a liquid which is either organic solvents, liquid drilling waste or paint.
• the process in ⁇ cludes the step of inducing combustion in the oxidizing means to convert the waste fine to non-combustible fines, molten slag and waste gas.
• the oxidizing mean is comprised of two oxidizers, the first oxidizer 26 and second oxidizer 56.
• the first oxidizer 26 a major portion of the combustible material is oxidized to form gaseous combustion by-products. These are drawn through the interior 52 of the first oxidizer 26 through the conduit 54 into the interior 58 of the second oxidizer 56. At the temperature of operation, 1800° to 3000° being preferred, some of the solid material is melted.
• This material collects at the bottom portion of the first oxidizer, as shown in Fig. 2 as the liquid slag 40, which then runs toward the slag port 42.
• the unmelted solid particulate material passes with the gaseous combustion by-products through the conduit 44 into the interior of oxidizer 56 wher ⁇ a portion may be melted in the second oxidizer 56 or it may remain unmelted and pass through the device as solid particulate fines.
• solid particulate primary aggregate and non-combustible fines are introduced into the oxidizing means.
• a conduit 102 introduces the primary aggregate and solid particulate fines to the interior of the second oxidizer 56.
• the primary aggregate and solid particulate fines are introduced in discrete batch portions. Continuous introduction of these materials into the oxidizer cools the surface of the pile of particulate material within the oxidizer preventing melting of the surface. This inhibits the melting of the particulate material being introduced to the oxidizer and thereby inhibits the production of the molten slag that forms the non-hazardous aggregate.
• the discrete batch portions of primary aggregate and non-combustible fines be introduced to the second oxi ⁇ dizer to form a pile in the oxidizer.
• Heat from the oxidiz ⁇ ing means is impinged on the surface of the pile whereupon material having relatively low melting points is melted to run down to the bottom of the oxidizer toward the conduit 54 where the molten material exits the slag port 42.
• the pro ⁇ cess may generate either slagged aggregate or non-combustible particulate fines that have a melting point higher than the temperature of the second oxidizer. Thus, such particular material would not be melted.
• the embodiment of Fig. 2 also shows an apparatus for injecting oxygen into the first oxidizer.
• the process is also operable with injection of oxygen into the second oxidizer.
• the average temperature in the first oxidizer is approximately 3000°F.
• Temperature in the conduit between the first and second oxidizer is 2800°F. and temperature in the second oxidizer is approximately 2800°F.
• the second oxidizer be disposed to receive liquid in rela ⁇ tively small amounts such that any combustible hazardous waste within the liquid is oxidized within the oxidizer means.
• it is the second oxidizer 56 that includes a inlet 60.
• the water is vaporized and the solids are introduced into the hot gas stream to be either combusted, melted or passed out with the other non-combustible particu ⁇ late fines into the downstream section of the apparatus.
• a dry spray reactor 62 includes means for injecting water into the dry spray reactor 62.
• the water forms a cooled effluent having a temperature of less than about 400°F. and preferably more than 350°F. It is further preferred that any acids in the cooled effluent be neutralized.
• a dry spray reactor 62 includes means for injecting water into the dry spray reactor 62.
• the water forms a cooled effluent having a temperature of less than about 400°F. and preferably more than 350°F. It is further preferred that any acids in the cooled effluent be neutralized.
• the apparatus includes means for introducing a caustic solution to form a neutralized effluent comprised of non-com ⁇ stible fines and waste gas.
• the waste gas is separated from the non-combustible fines by dry filtration. This step can be accomplished by passing the non-combustible fines and waste gas through a conventional baghouse.
• the fans associated with the baghouse, in this embodiment, fan 76 in Fig. 1, induce a draft throughout the entire apparatus such that the apparatus is operated at a pressure below atmospheric pressure.
• the process in ⁇ cludes a step of cooling the mixture of molten slag and solid particulates to form a non-hazardous aggregate.
• the mixture of molten slag and solid particulates is introduced to a water filled conveyer where the quenching effect of the water cools the mixture to form the solid non-hazardous, non-leaching aggregate.
• the water used to cool the molten material is then re-introduced to the process either with waste water into the second oxidizer or as water coolant into the quencher 62.
• Operation of the present invention results in the production of four effluents: ferrous metal, which is passed through the rotary kiln and is thus free of hazardous material; clinker that is passed through the rotary kiln, which if it contains hazardous material is either bound into the structure of the clinker or is re-introduced to the pro ⁇ cess until the clinker composition is non-hazardous.
• the third effluent is the gaseous effluent from the stack 80 and consists primarily of carbon dioxide and water. While the preferred embodiment is not classified as a hazardous waste incinerator and is not subject to hazardous waste incinera ⁇ tion requirements, its air quality permit is based on the same considerations applied to a Part "B" hazardous waste incinerator.
• the aggregate produced from the process while containing heavy metals that would be hazardous if removable from the aggregate has converted the material to a form where the heavy metals are bound into the glass-like aggregate.
• the levels of arsenic, barium, cadmium, chromium, lead, mercury, selenium and silver are all well below the regulatory limit.
• the con ⁇ centration of pesticide herbicide compounds, acid phenol compounds, base neutral compounds and other volatile com ⁇ pounds are well below the regulatory limits.
• the input materials may contain hazardous materials, the materials are either oxidized by oxidation or locked within the structure of the aggregate such that the process produces no hazardous effluents.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Soil Sciences (AREA)
• Processing Of Solid Wastes (AREA)
• Gasification And Melting Of Waste (AREA)
• Incineration Of Waste (AREA)

Priority Applications (9)

Applications Claiming Priority (2)

Publications (1)

Family

ID=22921058

Family Applications (1)

Country Status (16)

Cited By (3)

Families Citing this family (1)

Citations (4)

Family Cites Families (6)

• 1989
  • 1989-09-13 ZA ZA896971A patent/ZA896971B/xx unknown
  • 1989-09-13 MC MC892121D patent/MC2121A1/xx unknown
  • 1989-09-13 KR KR1019900701008A patent/KR950013974B1/ko active IP Right Grant
  • 1989-09-13 AU AU43014/89A patent/AU635224B2/en not_active Ceased
  • 1989-09-13 HU HU895524A patent/HU209764B/hu not_active IP Right Cessation
  • 1989-09-13 WO PCT/US1989/003878 patent/WO1990002910A1/en active Application Filing
  • 1989-09-13 JP JP1510111A patent/JPH07117223B2/ja not_active Expired - Lifetime
  • 1989-09-13 BR BR898907653A patent/BR8907653A/pt not_active IP Right Cessation
  • 1989-09-14 PL PL89281450A patent/PL164472B1/pl unknown
• 1990
  • 1990-10-05 DK DK241690A patent/DK241690D0/da not_active Application Discontinuation
• 1991
  • 1991-03-01 OA OA59966A patent/OA09639A/en unknown
  • 1991-03-12 BG BG094026A patent/BG94026A/bg unknown
  • 1991-03-12 FI FI911210A patent/FI911210A0/fi not_active Application Discontinuation
  • 1991-03-13 NO NO910991A patent/NO300864B1/no not_active IP Right Cessation
  • 1991-05-14 HU HU91823A patent/HU910823D0/hu unknown
• 1992
  • 1992-12-23 LV LV920412A patent/LV10339A/xx unknown
• 1993
  • 1993-03-15 LT LTIP411A patent/LTIP411A/xx unknown

Patent Citations (4)

Also Published As

Similar Documents

Legal Events