CA2158553A1 - Solid waste conversion process and apparatus - Google Patents
Solid waste conversion process and apparatusInfo
- Publication number
- CA2158553A1 CA2158553A1 CA 2158553 CA2158553A CA2158553A1 CA 2158553 A1 CA2158553 A1 CA 2158553A1 CA 2158553 CA2158553 CA 2158553 CA 2158553 A CA2158553 A CA 2158553A CA 2158553 A1 CA2158553 A1 CA 2158553A1
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- Prior art keywords
- solution
- gaseous byproducts
- reacted
- conversion process
- process according
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
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- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Treating Waste Gases (AREA)
Abstract
A solid waste conversion process and apparatus for converting solid waste having long carbon chains and hydrogen groups and having by mass less than 80 % water are disclosed. The solid waste material is dissociated substantially in the absence of oxygen into unstable gaseous byproducts and particulate matter and the bonds in the long carbon chains are broken. In a condenser system the unstable gaseous byproducts are condensed into a reacted solution comprising liquid hydrocarbons. The condenser system utilizing a hydroxyde or carbonate base solution, preferably a sodium hydroxide solution. Preferably the liquid hydrocarbons are separated from the reacted solution. The condenser system may include the steps of spraying the unstable gaseous byproducts with the solution to form reacted gases and cooling the reacted gases. Alternatively the condenser system may include the steps of partially cooling the unstable gaseous byproducts and maintaining the unstable gaseous byproducts in their unstable form so that stable gases do not form and condensing the partially cooled unstable gaseous byproducts in a catalytic condenser containing the solution.
Description
~ WO 94/21329 21 5 8 5 5 3 PCT/CA94/00152 SO~ WASTE CON~ERSION PROCESS AND APPAR~TUS
TECHNICAL FI}~LD
This invention relates to solid waste disposal and in particular a method 5 and appal~lus for the conversion of solid waste m~t~ri~l by destructive fli~till~tion of waste m~teri~l and reacting of gaseous byproducts in a catalytic con-l~n~er.
BACKGROUND OF THE INVENTION
There is a growing col~cern reg~ding the disposal of waste in general 10 and in particular the disposal of biom~Aic~l and other ha_ardous wastes. Specifically, with respect to biomYlic~l wastes there are not only all the problems associated with waste disposal in general but also the problems of properly disposing of waste cont~min~ted by bacteria and viruses. Accordingly there is a need to manage and dispose of waste effectively and efficiently.
Various methods have been used for disposing of wastes including incineration and l~nflfill. Some of the typical con~xrn.~ oci~ted with these methods include finding environmlont~lly acceptable and politically acceptable landfill sites and incineration sites, building smoke stacks for incineration that are tall enough so that the gaseous waste is s-lfficiently diluted to meet the local standards, and transporting the waste to the disposal site. With regard to biomY1ic~l waste cont~min~t~oA bybacteria and viruses, it is il,lpol~nt that the bacteria and viruses are stçrili7~1 as part of the waste disposal process.
Disposing of waste through landfill is a very volatile political issue, since no one wants a landfill site in their back yard and yet no one wants to pay the high transportation costs ~ori~tPIi with transporting the waste to a remote site.
Further, the amount of waste that is generated and is filling our landfill sites is a serious problem. With regard to biom~Ai~l waste cont~min~tPd by bacteria and r viruses it is desirable to dispose of it either on site or as near thereto as possible so that any conf~min~tion by bacteria and/or viruses is cont~in~d. Typically where 30 landfill is the method of disposal this is not always possible. In addition where the waste is disposed of in a landfill site typically no steps are taken to stçrili7e the bacteria and viruses.
2i585~
Similarly disposing of waste through incineration is a volatile political issue and no one wants an incin~r~tion site in their backyard. Incineration is b~ ~lly burning the waste or converting it into ash and gas. Incineration has the advantage of being adaptable to stt~rili7e the bacteria and viruses. However, after 5 incineration the ash still has to be disposed of, typically in a landfill site. Further, at least some of the gases that are byproducts of incineration are harmful gases and typically these are released into the atmosphere. More recentIy incineration also incllldes scrubbers which process the gaseous byproducts of incineration. Although the scrubber ~palen~ly "clean" the gaseous byproducts the invisible gases released 10 into the atmosphere may still be harmful. Spe~ific~lly, some of the gaseous byproducts may be hydrocarbons which are known to be harmful if inh~led More recently attempts have been made to use pyrolysis to destroy waste. Pyrolysis overcomes many of the deficiencies of waste disposal through landfill or incineration since it reduces the volume and mass of the waste. These 15 systems however are typically de~i~n~l for specific types of waste. In an attempt to control the output, where the composition of the waste is varied, the process isadjusted by adding certain m~teri~l~ to the input. These systems are often impractical for biom~Aic~l or m~nicir~l waste because it is difficult to analyze the waste cor,lposilion prior to its disposal. In addition, pyrolysis typically has gaseous 20 hydroc~lJons as byproducts which, as tli~cn~ed above, are undesirable. Some of these systems are used in combination with scrubbers. Spe~ifir~lly U.S. Patent 5,010,829 issued to P. Klllk~rni on April 20, 1991 and U.S. Patent 4,934,286 issued to B.P. Fowler on June 19, 1990 show systems which destroy the waste through pyrolysis and then remove chlorine by passing the cooled gaseous byproducts through 25 an NaOH tower.
Molten baths have been used in the past, as a step of a mamlf~st~lring process, as a means for heating and/or vaporizing materi~l~. These baths, however, were not used for solid waste or biom~Ai~l waste disposal because of the helelogellous nature of the waste and its high water content since water, when 30 vaporized, in a molten bath would cause explosions.
More recently molten baths have been used in the treatment of sludge.
~158~3 Spe~ific~lly United States patent number 4,173,190 issued to Greenberg et al. shows a coiled tube immersed in a molten salt bath. The sludge and hot air mixture is dried and burned in the coiled tube. This system, however, is an oxygen based system and the sludge is not submerged in the bath.
Until the present invention there has not been a method and a~pa-~Lus for converting the gaseous byproducts of the waste into liquid hydrocarbons rather than gaseous hydr~l,o"s.
DISCLOSURE OF INVENTION
The present invention provides for the combining of dissociated solid waste with hydroxide ions to form liquid hydrocarbons. A hydroxide or carbonate base solution is used to provide the hydroxide ions.
According to one aspect of the invention there is provided a solid waste conversion process for converting solid waste having long carbon chains and hydrogen groups and having by mass less than 80% water are disclosed. The solid waste material is dissociated substantially in the absence of oxygen into unstable gaseous byproducts and particulate matter and the bonds in the long carbon chains are broken.
In a con~ensPr system the unstable gaseous byproducts are conden~ed into a reacted solution comprising liquid hydr~c~bons. The cond~n~er system utili7.in~ a hydroxide or carbonate base solution, preferably a sodium hydroxide solution. Preferably the liquid hydloc~bons are s~al~led from the reacted solution. According to another aspect of the invention the condenser system includes the steps of spraying the unstable gaseous byproducts with the solution to form reacted gases and cooling the reacted gases.
.Al~e~ ely according to another aspect of the invention the con-len~er system includes the steps of partially cooling the unstable gaseous byproducts and g the unstable gaseous byproducts in their unstable form so that stable gases - do not form and con-len~ing the partially cooled unstable gaseous byproducts in a catalytic conden~er con~ g the solution.
According to a further aspect of the invention an apparatus is provided for converting solid waste having long carbon chains. The appal~tus comprises a feed wo 94/21329 2 iS~S PCT/CA94/00152 system for transporting the waste subst~nti~lly without introducing oxygen into the system. A sealed reaction vessel is provided for receiving the waste from the feed system. A heat source is provided to heat the waste subst~nti~lly in the absence of oxygen to temperatures so that the solid waste dissociates into unstable gaseousS byproducts and particulate matter and so that the bonds in the long carbon chains are broken. A condenser system is provided which is downstream of the heating sourceand in which the unstable gaseous byproducts is reacted with a solution chosen from the group con~istin~; of hydroxide bases and carbonate bases to produce a reacted solution comprising at least some liquid hydrocarbons.
According to a still further aspect of the invention the condenser system comprises a sealed catalytic conversion chamber including a means for spraying the unstable gaseous byproducts with the solution to form reacted gases and a means for cooling the reacted gases.
Alt~rn~tively according to a still further aspect of the invention the condenser system comprises a means for partially cooling the unstable gaseous byproducts and m~int~ining the unstable gaseous byproducts in their unstable form so that stable gases do not form and a catalytic condenser downstream of the partially cooling means the catalytic condenser co~ ing the solution for con~en~ing the partially cooled unstable gaseous byproducts.
Further features of the invention will be described or will become a~nt in the course of the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be more clearly understood, the plerell~d emborliment~ thereof will now be described in detail by way of example, with reference to the accompanying drawings, in which:
Fig. 1 is a schematic view of the process used for the destructive till~tion of solid waste material and the reacting of unstable gaseous byproducts thereof in a con~ien~p~r system of the present invention;
Fig. 2 is a schematic view of the process used for the destructive till~tion of solid waste material and the reacting of unstable gaseous byproducts 2158~3 thereof in a conden~er system of the present invention showing a condenser system in more detail;
Fig. 3 is diagl;1"~",~l;c view of the a~p~dt.ls of the process shown in Fig. 2;
Fig. 4 is a sçhpm~tic view of the process used for the destructive till~tion of solid waste m~t~,ri~l and the reacting of unstable gaseous byproducts thereof in a con~en~Pr system of the present invention showing an alternate con~len~,r system in more detail;
Fig. 5 is diagr~mm~tic view of the a~ald~.ls of the process shown in Fig. 4;
Fig. 6 is a vertical sectional view of a catalytic condenser shown in Fig.
5; and Fig. 7 is a horizontal sectional view of a catalytic condenser shown in Figs. 5 and 6.
MODES FOR CARRYING QUT THE INVENTION
In the following ~ c~ ion the term destructive ~ till~tion will be understood to mean the çhemic~l deco",posiLion of matter into smaller and simpler molecules. The reaction takes place by the application of energy in the absence of oxygen so that no combustion takes place. The process is endothermic and therefore there must be a constant application of energy to sustain the process. Destructive till~tinn is also som~times referred to as pyrolysis but that term could also refer to reactions which take place in the presence of oxygen and therefore to emphasis that the process of the present invention takes place s--bs~ lly in the absence of oxygen the term destructive ~ till~tion will be used.
The process for destructive rli~till~tiQn of solid waste material and the reacting of the byproducts in a catalytic condenser will be liccl~seA generally first, - followed by a ~ c~ ion of the a~a dlus of the plerelled embo~liment~.
Referring to the drawings, and in particular to Fig. 1, the process for the conversion of solid waste material by destructive ~ till~tion and the reacting of unstable gaseous byproducts in a catalytic condenser is shown generally at 10. The wo 9412L~29 ~$~$ PCT/CA94/00152 main components of the system iriclude a feed system 12, a reaction vessel or reactor 14 and a conclçn.~-r system 16.
The waste material is fed into the reaction vessel through feed system 12. The feed system is adapted to minimi7P the amount of oxygen that enters the 5 reactor 14. It is important to minimi7e the amount of oxygen in the reactor 14 to minimi7e and if possible e1imin~tt~ the amount of combustion that occurs.
In reactor 14 the waste is processed by destructive ~ till~tion reslllting in unstable gaseous byproducts and particulate matter or solids 18. In order to achieve destructive ~ till~tion of the waste, the waste products are heated to a10 tt;",peldture greater than the vaporization te"~ldL~Ire of the m~t~ . Further, the ten,p~;ldture needs to be above the te",peldture at which the bonds in the long carbon chains are broken. Typically a minimum temperature of 800C will be adequate formost species of hyd,o.;a,l,ons. Where the te",l.eldt~lre is above that at which the bonds in the hydrogen groups are broken, simple hydrocarbons will be left. This will 15 typically occur at ~elll~GldlUlkS over 1100C. In some circllmst~nces it will be desirable to break the waste m~t~qri~l down into simple hydrocarbons but it will be appreciated that this will take more heat and therefore will be more costly.
It will be appreciated by someone skilled in the art that the destructive distill~tion described above could also be described in terms of energy. That is, 20 enough energy is added to the reactor 14 so that the bonds in the long carbon chains are broken. Typically the amount of energy that is required to break the long chain carbons is 80 kcal/mole and to break the bonds in the hydrogen groups is approximately 110 kcal/mole.
Further, it will be appreciated by someone skilled in the art that in the 25 above and following description the following definitions were used. The term long carbon chains refers to molecules having more than two carbons in the molecule. The bonds can be double or triple carbon bonds. Therefore when long carbon chains are broken this means that carbon r~dicles are formed. The term hydrogen groups means molecules having hydrogen as part of the molecule but it does not include hydrogen 30 on its own.
To break the long chain carbons, a variety of methods could be used in WO 94/2L~29 215 8 5 5 3 PCTtCA94/00152 reactor 14 and the most a~l~,iate method can be chosen by someone skilled in theart. For eY~mple a plasma torch could be used as a heat or energy source.
Alternatively a sand bath or heat bath could be used as a heat or energy source.Similarly other material with a high heat capacity could be used as a heat source.
Condenser system 16 utilizes a hydroxide or carbonate base solution.
The hydroxide or carbonate base dissolves in water and s~a,d~s into ions.
Preferably sodium hydroxide is used since the sodium ion will combine with chloride ions which are present and form sodium chloride, particulate matter. In the catalytic condenser 16 the unstable gaseous byproducts react with the sodium, hydroxide, and hydrogen in the sodium hydroxide solution to form liquid hydrocarbons, weak alcohols or weak acids, water and salts. In Fig. 1 only liquid hydrocarbons 20, water 22 and particulates 24 are shown since these are the primary products of the process.
An embodiment of the system will now be described with reference to Figs. 2 and 3. In this embodiment the condenser system includes a catalytic conversion chamber 26, a first mist elimin~tor 28 and a second mist elimin~tor 30.
In the catalytic conversion chamber 26 the unstable gaseous byproduct is reacted with sodium hydroxide solution to form converted gases. These converted gases are processed in a first mist eli",i~ r 28 where the converted gases are cooled to a tt;lllp~ld~lre of 100C. At this ~Illpeldtulc water 22 will condense. A second mist elimin~tQr 30 cools the converted gas to below where liquid hydrocarbons 20 will form a condense. Typically the gases will be cooled to standard te"~;,dture and ples~iUl~. It will be appreciated by someone skilled in the art that multiple mist eli"linAt-,ls could be used to remove specific liquid hydrocarbons since each liquid hydrocarbons have a specific te"~ldLIlre at which it will change phase from gas to liquid. For example methanol (methyl alcohol) changes phase at approximately 67C, ethanol (ethyl alcohol) changes phase at 78C, benæne changes phase at 80.1C and acetone changes phase at 56.5C
When the unstable gaseous byproducts react with sodium hydroxide solution particulate matter 24, for example sodium chlori~l~, will also form.
Particulate matter 24 can be removed from the system wherever practicable by well known methods and this is shown between catalytic conversion chamber 26 and first Wo 94/21329 ~, lS ~ ~ S ~ PCT/CA94/00152 mist elimin~tor 28.
Fig. 3 shows a ~ r~mm~tic view of the apparatus for the system shown in Fig. 2. Catalytic conversion chamber 26 has a plurality of spray nozzles or atomizers for spraying the incoming unstable gaseous byproduct shown by arrow 32with sodium hydroxide solution. Catalytic conversion chamber 26 and the plurality of nozzles are configured to ensure that the dwell time of the unstable gaseous byproduct in the sodium hydroxide spray allows for the combination of the hydroxide ion with the unstable gases. The concentration of sodium hydroxide in the solution which is used is as high as practicable. As discussed above in the catalytic conversion chamber 26, in part, the hydroxide ion will combine with unstable gaseous byproducts to form water and hydrocarbons, generally referred to as converted gases. As the converted gases exit the catalytic conversion chamber 26 the converted gases are still gases and need to be cooled to become liquids.
A conduit 34 between the catalytic conversion chamber 26 and a first mist ~limin~tor 28, described below, is configured so that the velocity of the reacted gases is re~uce i. This will allow particulates, shown by arrow 36 which have formed in the catalytic conversion chamber 26 to be collected and removed or recycled. As shown in Fig. 3, conduit 34 has an elbow and a reservoir 38 for collecting and removing particulates. The particulates are predominantly sodium chloride when sodium hydroxide solution is used as the spray. The particulates can be recycled back through conduit 40 and used in the spray as catalytic conversion chamber 26. Theconc~ontr~tinn of the sodium hydroxide will be monitored. Periodically the reservoir may be flushed as neerlecl First mist eli",;n~tQl 28 cools the reacted gases to a temperature between 100C and 85C at which temperature H2O will change phase, ch~nginp from gas to liquid.
Second mist elimin~tor 30 cools the rem~ining reacted gases to a temperature at which t~",pelature the liquid hydrocarbons will condense. Typically the te"~eiature of second mist elimin~tor 30 will be between 80C and standard temperature and pressure. ~ r~l~bly it will be at 55C.
Where there are some gases which pass through the system without Wo 94/2L~29 215 8 5 5 ~ PCT/CA94/00152 comhining to form water, liquid hydrocarbons or particulate matter these gases are routed back to the catalytic conversion chall,bel 26. Hydrogen is an example of a gas which may do this.
An ~ltern~te con~en~ing system may be used, wherein rather than the 5 sodium hydroxide being sprayed on the unstable gas stream and then the reacted gases are cooled to form liquids, as described above, the unstable gas stream is partially cooled but l,,~ in~l in an unstable state and then bubbled through a sodium hydroxide solution. This alternate system will now be ~ c~ Pd with reference to Figs. 4-7.
The unstable gaseous byproducts are transported from the reactor 14 to the catalytic conden~Pr S0. During transportation, the unstable gaseous byproducts are cooled but no lower than the tem~l~tu~ at which the gases will recombine or at which the gases become stable. For most appli~tion~ the gases will be cooled to about 400C.
The catalytic condenser 50 utilizes a hydroxide or call,ollate base solution. The hydro~ide or c~l.ona~e base dissolves in water and sel)andtes into ions.
Preferably sodium hydroxide is used since the sodium ion will combine with chloride ions which are present and form sodium chloride a co,.,pou,ld which is highly soluble in water. ~ltPrn~tively if a carbonate base is used ~ ilates will from which should be removed before the solution enters the reverse osmosis unit.
In the catalytic condenser 50 cont~ lillg a sodium hydroxide solution, the unstable gaseous byproducts react with the so~ m, hydroxide, and hydrogen toform liquid hydrocarbons, weak alcohols or weak acids and salts. The pH of the solution is monitored to ~ i" a s~lfficient amount of sodium and hydroxide in the system. The pH is ",~inl~ d between 9 and 12 and is preferably at 10. The solution is m~int~ined at a lelllp~ Ltule below which the gases will recombine with the sodium hydroxide solution. For most applications the conciçn~er will be kept below 65C and preferably at room ~e~"~ "c, approxim~tP-ly 25C.
In the sepa-~tor 52 the liquid hydrocarbons 20 are se~ from the sodium hydroxide solution. This can be done by reverse osmosis. The liquid hydrocarbons 20 can then be further separated into distinct hydrocarbons by Wo 94/2L~29 ? i $ ~ S 5 3 PCT/CA94/00152 conventional methods.
The sodium hydroxide solution which has been se~ ~i from the liquid hydrocarbons 20 is transported to the ~ till~tinn chamber 54 where it is separated into water 22 having some carbonate and sodium chloride dissolved therein S and salts, primarily sodium chloride. The salts are stored in reservoir 56 and are available for recycling into the catalytic condenser as nP~etl.
Referring to Fig. 5, a conduit 58 is connecte~l between the reactor 14 and the catalytic condenser 50. In the conduit 58 the gases are cooled but no lower than the lelnpe.ature at which they will recombine or become stable, for most applications the gases will be cooled to about 400C. A bag house 60 is attached to the conduit 58 to allow for the removal of particulate matter which is airborne in the gases. A blower 62 is conn~ct~l to the conduit 58 between the bag house 60 and the catalytic condenser 50 to ~ inli-in an e~uilibrium between the gas ~lCS:iULc in the conduit 58 and the liquid p-cs~ule in the condenser 50.
The catalytic condenser 50 shown in Figs. 6 and 7 is a sealed vessel filed with a hydroxide or c~b~ ate base solution 64, preferably sodium hydroxide.
An inlet pipe 66 is connçct~d a pair of spaced apart top 68 and bottom 70 spargeplates. The inlet pipe 66 is an exten~ion of the conduit 58. The peripheral edge 72 of the sparge plates are ~tt~h~d together. The top sparge plate 68 has a plurality of 20 holes 74 as shown in detail in Fig. 7 formed therein through which the gas is released into the solution as shown by arrows 76 in Fig. 6. The holes are as small as possible so that no large bubbles are allowed to form in the solution and are preferably .0059"
in ~ met~r. A heat exchanger 78 (shown in Fig. 5) is attached to the con-içn~çr 50 at port 80 to m~int~in the lelllpeldlule of the solution at less than 65C and preferably at 25 25C. A pH monitoring device (not shown) is ~tt~he~ to port 80 to measure the pH
of the solution and sodium hydroxide from reservoir 56 (shown in Fig. 5) is added to the condenser 50 intermittçntly as needed. The pH of the condenser should be m~int~ined in the range of 9 to 12 and is preferably at 10. The condenser 50 is sealed so that all of the unstable gaseous byproduct is forced to go through the sodium30 hydroxide solution and there is no exhaust pipe for any gases to escape.
The reacted sodium hydroxide solution is drawn off at a predetermined i-- WO 94/2L~29 21 5 ~ 5 ~ ~ PCT/CA94/00152 rate through the outflow 82. The rate that the liquid is drawn off is equivalent to the rate that liquid hydrocarbons are being produced in the condenser.
As shown in Fig. 4, the drawn off liquid is then processed by a reverse o.~mo~i~ se~aldlol 84 which se~aldtes the liquid into liquid hydrocarbons and reacted 5 sodium hydroxide solution. The liquid hydrocarbons are then removed as shown by arrow 86. Preferably the reverse osmosis se~)~r~or will be one which uses a cellulose membrane. The liquid hydrocarbons which are sep~ d in the reverse osmosis sep~dtor are then ready for reuse or separation by any conventional method.
The reacted sodium hydroxide solution is conducted to a ~ till~tion 10 chamber 54. Preferably the pipes 88 which conduct the reacted sodium hydroxide to the ~ till~tion chamber 54 are wound around the conduit 58 so that the reacted sodium hydroxide solution will cool the gases in conduit 58 while the gases will heat up the reacted sodium hydroxide solution in pipes 88. The reacted sodium hydroxide solution will be heated to less than its boiling point to minimi7e any precipitate 15 re~ ining in pipes 88. Preferably the reacted sodium hydroxide solution will be heated to 65C in the pipes. In the rli~till~tion chamber 54 the reacted sodium hydroxide solution is se~ ed into water having some carbonate and sodium chloride dissolved therein and salts, primarily sodium hydroxide. The (~i~tilled water can then be disposed of or used as required and it is removed as shown by arrow 90. The 20 salts, primarily sodium hydroxide, are stored in the reservoir 56 to be used as needed In the plcfellc;d emb~iml~-nt for input waste of 50% water, 18%
plastics, 25% hydrocarbons and 7% glass and metals in general the following occurs.
In the reactor 14 the waste is dissociated into water vapour, carbon monoxide, 25 chloride ion, carbon dioxide, hydrogen gas, small chain hydrocarbons and/or simple hydrocarbons, sulphur, nitrogen ions, carbon, char, glass and metals. In the catalytic condçn~çr the sodium hydroxide ~ oci~teS in water into sodium ion and hydroxide ion; the carbon dioxide dissolves in water; the chlorine ion combines with the sodium ion to form sodium chloride, the carbon monoxide and the small chain hydrocarbons 30 and/or simple hydrocarbons combine with the hydrogen ion and the hydroxide ion to form weak alcohols or weak acids and liquid hydrocarbons; the sulphur forms sulphur wo 94~21329 2 i S 8 ~ 5 ~ PCTICA94/00152 ~l based salts; the nil,ogen forms nitrogen based salts; and some of the sodium mayform sodium based salts. In the reverse osmosis sæ~ or the hydrocarbons are removed from the saline solutiom In the ~i~till~tion chamber water with minor amounts of weak hydloc~bons, carbonates and sodium chloride which were not 5 removed by the reverse osmosis unie is boiled off and then condensed; and a residue of salts, primarily sodium hydroxide, is stored in the reservoir.
It will be appreciated that the above description related to the plc;rell~d embodiment by way of example only. Many variations on the invention will be obvious to those knowledgeable in the field, and such obvious variations are within 10 the scope of the invention as described and cl~imP~, whether or not expressly described.
The process is for solid waste m~teri~l having, by mass, less than 80%
water. The process is specifically designP~I for biome~ l waste material which has a typical co,l,~osi~ion by mass of 50% water, 18% plastic, 25% hydrocarbons and 7%15 glass and metals. The process could also be used for the conversion of such things as tires. Some mol1ifir~tions of the process may be needed to adapt the process to other types of waste but these mo~lifir~tions are int~n-led to be within the scope of the invention and would be obvious to someone skilled in the art.
For in~t~nce, it will be appl~iated by someone skilled in the art that 20 the feed tube system could be modified to allow for alternate methods of feeding the waste material into the reactor and minimi7ing the amount of air that gets into the cli~till~tinn vessel.
TECHNICAL FI}~LD
This invention relates to solid waste disposal and in particular a method 5 and appal~lus for the conversion of solid waste m~t~ri~l by destructive fli~till~tion of waste m~teri~l and reacting of gaseous byproducts in a catalytic con-l~n~er.
BACKGROUND OF THE INVENTION
There is a growing col~cern reg~ding the disposal of waste in general 10 and in particular the disposal of biom~Aic~l and other ha_ardous wastes. Specifically, with respect to biomYlic~l wastes there are not only all the problems associated with waste disposal in general but also the problems of properly disposing of waste cont~min~ted by bacteria and viruses. Accordingly there is a need to manage and dispose of waste effectively and efficiently.
Various methods have been used for disposing of wastes including incineration and l~nflfill. Some of the typical con~xrn.~ oci~ted with these methods include finding environmlont~lly acceptable and politically acceptable landfill sites and incineration sites, building smoke stacks for incineration that are tall enough so that the gaseous waste is s-lfficiently diluted to meet the local standards, and transporting the waste to the disposal site. With regard to biomY1ic~l waste cont~min~t~oA bybacteria and viruses, it is il,lpol~nt that the bacteria and viruses are stçrili7~1 as part of the waste disposal process.
Disposing of waste through landfill is a very volatile political issue, since no one wants a landfill site in their back yard and yet no one wants to pay the high transportation costs ~ori~tPIi with transporting the waste to a remote site.
Further, the amount of waste that is generated and is filling our landfill sites is a serious problem. With regard to biom~Ai~l waste cont~min~tPd by bacteria and r viruses it is desirable to dispose of it either on site or as near thereto as possible so that any conf~min~tion by bacteria and/or viruses is cont~in~d. Typically where 30 landfill is the method of disposal this is not always possible. In addition where the waste is disposed of in a landfill site typically no steps are taken to stçrili7e the bacteria and viruses.
2i585~
Similarly disposing of waste through incineration is a volatile political issue and no one wants an incin~r~tion site in their backyard. Incineration is b~ ~lly burning the waste or converting it into ash and gas. Incineration has the advantage of being adaptable to stt~rili7e the bacteria and viruses. However, after 5 incineration the ash still has to be disposed of, typically in a landfill site. Further, at least some of the gases that are byproducts of incineration are harmful gases and typically these are released into the atmosphere. More recentIy incineration also incllldes scrubbers which process the gaseous byproducts of incineration. Although the scrubber ~palen~ly "clean" the gaseous byproducts the invisible gases released 10 into the atmosphere may still be harmful. Spe~ific~lly, some of the gaseous byproducts may be hydrocarbons which are known to be harmful if inh~led More recently attempts have been made to use pyrolysis to destroy waste. Pyrolysis overcomes many of the deficiencies of waste disposal through landfill or incineration since it reduces the volume and mass of the waste. These 15 systems however are typically de~i~n~l for specific types of waste. In an attempt to control the output, where the composition of the waste is varied, the process isadjusted by adding certain m~teri~l~ to the input. These systems are often impractical for biom~Aic~l or m~nicir~l waste because it is difficult to analyze the waste cor,lposilion prior to its disposal. In addition, pyrolysis typically has gaseous 20 hydroc~lJons as byproducts which, as tli~cn~ed above, are undesirable. Some of these systems are used in combination with scrubbers. Spe~ifir~lly U.S. Patent 5,010,829 issued to P. Klllk~rni on April 20, 1991 and U.S. Patent 4,934,286 issued to B.P. Fowler on June 19, 1990 show systems which destroy the waste through pyrolysis and then remove chlorine by passing the cooled gaseous byproducts through 25 an NaOH tower.
Molten baths have been used in the past, as a step of a mamlf~st~lring process, as a means for heating and/or vaporizing materi~l~. These baths, however, were not used for solid waste or biom~Ai~l waste disposal because of the helelogellous nature of the waste and its high water content since water, when 30 vaporized, in a molten bath would cause explosions.
More recently molten baths have been used in the treatment of sludge.
~158~3 Spe~ific~lly United States patent number 4,173,190 issued to Greenberg et al. shows a coiled tube immersed in a molten salt bath. The sludge and hot air mixture is dried and burned in the coiled tube. This system, however, is an oxygen based system and the sludge is not submerged in the bath.
Until the present invention there has not been a method and a~pa-~Lus for converting the gaseous byproducts of the waste into liquid hydrocarbons rather than gaseous hydr~l,o"s.
DISCLOSURE OF INVENTION
The present invention provides for the combining of dissociated solid waste with hydroxide ions to form liquid hydrocarbons. A hydroxide or carbonate base solution is used to provide the hydroxide ions.
According to one aspect of the invention there is provided a solid waste conversion process for converting solid waste having long carbon chains and hydrogen groups and having by mass less than 80% water are disclosed. The solid waste material is dissociated substantially in the absence of oxygen into unstable gaseous byproducts and particulate matter and the bonds in the long carbon chains are broken.
In a con~ensPr system the unstable gaseous byproducts are conden~ed into a reacted solution comprising liquid hydr~c~bons. The cond~n~er system utili7.in~ a hydroxide or carbonate base solution, preferably a sodium hydroxide solution. Preferably the liquid hydloc~bons are s~al~led from the reacted solution. According to another aspect of the invention the condenser system includes the steps of spraying the unstable gaseous byproducts with the solution to form reacted gases and cooling the reacted gases.
.Al~e~ ely according to another aspect of the invention the con-len~er system includes the steps of partially cooling the unstable gaseous byproducts and g the unstable gaseous byproducts in their unstable form so that stable gases - do not form and con-len~ing the partially cooled unstable gaseous byproducts in a catalytic conden~er con~ g the solution.
According to a further aspect of the invention an apparatus is provided for converting solid waste having long carbon chains. The appal~tus comprises a feed wo 94/21329 2 iS~S PCT/CA94/00152 system for transporting the waste subst~nti~lly without introducing oxygen into the system. A sealed reaction vessel is provided for receiving the waste from the feed system. A heat source is provided to heat the waste subst~nti~lly in the absence of oxygen to temperatures so that the solid waste dissociates into unstable gaseousS byproducts and particulate matter and so that the bonds in the long carbon chains are broken. A condenser system is provided which is downstream of the heating sourceand in which the unstable gaseous byproducts is reacted with a solution chosen from the group con~istin~; of hydroxide bases and carbonate bases to produce a reacted solution comprising at least some liquid hydrocarbons.
According to a still further aspect of the invention the condenser system comprises a sealed catalytic conversion chamber including a means for spraying the unstable gaseous byproducts with the solution to form reacted gases and a means for cooling the reacted gases.
Alt~rn~tively according to a still further aspect of the invention the condenser system comprises a means for partially cooling the unstable gaseous byproducts and m~int~ining the unstable gaseous byproducts in their unstable form so that stable gases do not form and a catalytic condenser downstream of the partially cooling means the catalytic condenser co~ ing the solution for con~en~ing the partially cooled unstable gaseous byproducts.
Further features of the invention will be described or will become a~nt in the course of the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be more clearly understood, the plerell~d emborliment~ thereof will now be described in detail by way of example, with reference to the accompanying drawings, in which:
Fig. 1 is a schematic view of the process used for the destructive till~tion of solid waste material and the reacting of unstable gaseous byproducts thereof in a con~ien~p~r system of the present invention;
Fig. 2 is a schematic view of the process used for the destructive till~tion of solid waste material and the reacting of unstable gaseous byproducts 2158~3 thereof in a conden~er system of the present invention showing a condenser system in more detail;
Fig. 3 is diagl;1"~",~l;c view of the a~p~dt.ls of the process shown in Fig. 2;
Fig. 4 is a sçhpm~tic view of the process used for the destructive till~tion of solid waste m~t~,ri~l and the reacting of unstable gaseous byproducts thereof in a con~en~Pr system of the present invention showing an alternate con~len~,r system in more detail;
Fig. 5 is diagr~mm~tic view of the a~ald~.ls of the process shown in Fig. 4;
Fig. 6 is a vertical sectional view of a catalytic condenser shown in Fig.
5; and Fig. 7 is a horizontal sectional view of a catalytic condenser shown in Figs. 5 and 6.
MODES FOR CARRYING QUT THE INVENTION
In the following ~ c~ ion the term destructive ~ till~tion will be understood to mean the çhemic~l deco",posiLion of matter into smaller and simpler molecules. The reaction takes place by the application of energy in the absence of oxygen so that no combustion takes place. The process is endothermic and therefore there must be a constant application of energy to sustain the process. Destructive till~tinn is also som~times referred to as pyrolysis but that term could also refer to reactions which take place in the presence of oxygen and therefore to emphasis that the process of the present invention takes place s--bs~ lly in the absence of oxygen the term destructive ~ till~tion will be used.
The process for destructive rli~till~tiQn of solid waste material and the reacting of the byproducts in a catalytic condenser will be liccl~seA generally first, - followed by a ~ c~ ion of the a~a dlus of the plerelled embo~liment~.
Referring to the drawings, and in particular to Fig. 1, the process for the conversion of solid waste material by destructive ~ till~tion and the reacting of unstable gaseous byproducts in a catalytic condenser is shown generally at 10. The wo 9412L~29 ~$~$ PCT/CA94/00152 main components of the system iriclude a feed system 12, a reaction vessel or reactor 14 and a conclçn.~-r system 16.
The waste material is fed into the reaction vessel through feed system 12. The feed system is adapted to minimi7P the amount of oxygen that enters the 5 reactor 14. It is important to minimi7e the amount of oxygen in the reactor 14 to minimi7e and if possible e1imin~tt~ the amount of combustion that occurs.
In reactor 14 the waste is processed by destructive ~ till~tion reslllting in unstable gaseous byproducts and particulate matter or solids 18. In order to achieve destructive ~ till~tion of the waste, the waste products are heated to a10 tt;",peldture greater than the vaporization te"~ldL~Ire of the m~t~ . Further, the ten,p~;ldture needs to be above the te",peldture at which the bonds in the long carbon chains are broken. Typically a minimum temperature of 800C will be adequate formost species of hyd,o.;a,l,ons. Where the te",l.eldt~lre is above that at which the bonds in the hydrogen groups are broken, simple hydrocarbons will be left. This will 15 typically occur at ~elll~GldlUlkS over 1100C. In some circllmst~nces it will be desirable to break the waste m~t~qri~l down into simple hydrocarbons but it will be appreciated that this will take more heat and therefore will be more costly.
It will be appreciated by someone skilled in the art that the destructive distill~tion described above could also be described in terms of energy. That is, 20 enough energy is added to the reactor 14 so that the bonds in the long carbon chains are broken. Typically the amount of energy that is required to break the long chain carbons is 80 kcal/mole and to break the bonds in the hydrogen groups is approximately 110 kcal/mole.
Further, it will be appreciated by someone skilled in the art that in the 25 above and following description the following definitions were used. The term long carbon chains refers to molecules having more than two carbons in the molecule. The bonds can be double or triple carbon bonds. Therefore when long carbon chains are broken this means that carbon r~dicles are formed. The term hydrogen groups means molecules having hydrogen as part of the molecule but it does not include hydrogen 30 on its own.
To break the long chain carbons, a variety of methods could be used in WO 94/2L~29 215 8 5 5 3 PCTtCA94/00152 reactor 14 and the most a~l~,iate method can be chosen by someone skilled in theart. For eY~mple a plasma torch could be used as a heat or energy source.
Alternatively a sand bath or heat bath could be used as a heat or energy source.Similarly other material with a high heat capacity could be used as a heat source.
Condenser system 16 utilizes a hydroxide or carbonate base solution.
The hydroxide or carbonate base dissolves in water and s~a,d~s into ions.
Preferably sodium hydroxide is used since the sodium ion will combine with chloride ions which are present and form sodium chloride, particulate matter. In the catalytic condenser 16 the unstable gaseous byproducts react with the sodium, hydroxide, and hydrogen in the sodium hydroxide solution to form liquid hydrocarbons, weak alcohols or weak acids, water and salts. In Fig. 1 only liquid hydrocarbons 20, water 22 and particulates 24 are shown since these are the primary products of the process.
An embodiment of the system will now be described with reference to Figs. 2 and 3. In this embodiment the condenser system includes a catalytic conversion chamber 26, a first mist elimin~tor 28 and a second mist elimin~tor 30.
In the catalytic conversion chamber 26 the unstable gaseous byproduct is reacted with sodium hydroxide solution to form converted gases. These converted gases are processed in a first mist eli",i~ r 28 where the converted gases are cooled to a tt;lllp~ld~lre of 100C. At this ~Illpeldtulc water 22 will condense. A second mist elimin~tQr 30 cools the converted gas to below where liquid hydrocarbons 20 will form a condense. Typically the gases will be cooled to standard te"~;,dture and ples~iUl~. It will be appreciated by someone skilled in the art that multiple mist eli"linAt-,ls could be used to remove specific liquid hydrocarbons since each liquid hydrocarbons have a specific te"~ldLIlre at which it will change phase from gas to liquid. For example methanol (methyl alcohol) changes phase at approximately 67C, ethanol (ethyl alcohol) changes phase at 78C, benæne changes phase at 80.1C and acetone changes phase at 56.5C
When the unstable gaseous byproducts react with sodium hydroxide solution particulate matter 24, for example sodium chlori~l~, will also form.
Particulate matter 24 can be removed from the system wherever practicable by well known methods and this is shown between catalytic conversion chamber 26 and first Wo 94/21329 ~, lS ~ ~ S ~ PCT/CA94/00152 mist elimin~tor 28.
Fig. 3 shows a ~ r~mm~tic view of the apparatus for the system shown in Fig. 2. Catalytic conversion chamber 26 has a plurality of spray nozzles or atomizers for spraying the incoming unstable gaseous byproduct shown by arrow 32with sodium hydroxide solution. Catalytic conversion chamber 26 and the plurality of nozzles are configured to ensure that the dwell time of the unstable gaseous byproduct in the sodium hydroxide spray allows for the combination of the hydroxide ion with the unstable gases. The concentration of sodium hydroxide in the solution which is used is as high as practicable. As discussed above in the catalytic conversion chamber 26, in part, the hydroxide ion will combine with unstable gaseous byproducts to form water and hydrocarbons, generally referred to as converted gases. As the converted gases exit the catalytic conversion chamber 26 the converted gases are still gases and need to be cooled to become liquids.
A conduit 34 between the catalytic conversion chamber 26 and a first mist ~limin~tor 28, described below, is configured so that the velocity of the reacted gases is re~uce i. This will allow particulates, shown by arrow 36 which have formed in the catalytic conversion chamber 26 to be collected and removed or recycled. As shown in Fig. 3, conduit 34 has an elbow and a reservoir 38 for collecting and removing particulates. The particulates are predominantly sodium chloride when sodium hydroxide solution is used as the spray. The particulates can be recycled back through conduit 40 and used in the spray as catalytic conversion chamber 26. Theconc~ontr~tinn of the sodium hydroxide will be monitored. Periodically the reservoir may be flushed as neerlecl First mist eli",;n~tQl 28 cools the reacted gases to a temperature between 100C and 85C at which temperature H2O will change phase, ch~nginp from gas to liquid.
Second mist elimin~tor 30 cools the rem~ining reacted gases to a temperature at which t~",pelature the liquid hydrocarbons will condense. Typically the te"~eiature of second mist elimin~tor 30 will be between 80C and standard temperature and pressure. ~ r~l~bly it will be at 55C.
Where there are some gases which pass through the system without Wo 94/2L~29 215 8 5 5 ~ PCT/CA94/00152 comhining to form water, liquid hydrocarbons or particulate matter these gases are routed back to the catalytic conversion chall,bel 26. Hydrogen is an example of a gas which may do this.
An ~ltern~te con~en~ing system may be used, wherein rather than the 5 sodium hydroxide being sprayed on the unstable gas stream and then the reacted gases are cooled to form liquids, as described above, the unstable gas stream is partially cooled but l,,~ in~l in an unstable state and then bubbled through a sodium hydroxide solution. This alternate system will now be ~ c~ Pd with reference to Figs. 4-7.
The unstable gaseous byproducts are transported from the reactor 14 to the catalytic conden~Pr S0. During transportation, the unstable gaseous byproducts are cooled but no lower than the tem~l~tu~ at which the gases will recombine or at which the gases become stable. For most appli~tion~ the gases will be cooled to about 400C.
The catalytic condenser 50 utilizes a hydroxide or call,ollate base solution. The hydro~ide or c~l.ona~e base dissolves in water and sel)andtes into ions.
Preferably sodium hydroxide is used since the sodium ion will combine with chloride ions which are present and form sodium chloride a co,.,pou,ld which is highly soluble in water. ~ltPrn~tively if a carbonate base is used ~ ilates will from which should be removed before the solution enters the reverse osmosis unit.
In the catalytic condenser 50 cont~ lillg a sodium hydroxide solution, the unstable gaseous byproducts react with the so~ m, hydroxide, and hydrogen toform liquid hydrocarbons, weak alcohols or weak acids and salts. The pH of the solution is monitored to ~ i" a s~lfficient amount of sodium and hydroxide in the system. The pH is ",~inl~ d between 9 and 12 and is preferably at 10. The solution is m~int~ined at a lelllp~ Ltule below which the gases will recombine with the sodium hydroxide solution. For most applications the conciçn~er will be kept below 65C and preferably at room ~e~"~ "c, approxim~tP-ly 25C.
In the sepa-~tor 52 the liquid hydrocarbons 20 are se~ from the sodium hydroxide solution. This can be done by reverse osmosis. The liquid hydrocarbons 20 can then be further separated into distinct hydrocarbons by Wo 94/2L~29 ? i $ ~ S 5 3 PCT/CA94/00152 conventional methods.
The sodium hydroxide solution which has been se~ ~i from the liquid hydrocarbons 20 is transported to the ~ till~tinn chamber 54 where it is separated into water 22 having some carbonate and sodium chloride dissolved therein S and salts, primarily sodium chloride. The salts are stored in reservoir 56 and are available for recycling into the catalytic condenser as nP~etl.
Referring to Fig. 5, a conduit 58 is connecte~l between the reactor 14 and the catalytic condenser 50. In the conduit 58 the gases are cooled but no lower than the lelnpe.ature at which they will recombine or become stable, for most applications the gases will be cooled to about 400C. A bag house 60 is attached to the conduit 58 to allow for the removal of particulate matter which is airborne in the gases. A blower 62 is conn~ct~l to the conduit 58 between the bag house 60 and the catalytic condenser 50 to ~ inli-in an e~uilibrium between the gas ~lCS:iULc in the conduit 58 and the liquid p-cs~ule in the condenser 50.
The catalytic condenser 50 shown in Figs. 6 and 7 is a sealed vessel filed with a hydroxide or c~b~ ate base solution 64, preferably sodium hydroxide.
An inlet pipe 66 is connçct~d a pair of spaced apart top 68 and bottom 70 spargeplates. The inlet pipe 66 is an exten~ion of the conduit 58. The peripheral edge 72 of the sparge plates are ~tt~h~d together. The top sparge plate 68 has a plurality of 20 holes 74 as shown in detail in Fig. 7 formed therein through which the gas is released into the solution as shown by arrows 76 in Fig. 6. The holes are as small as possible so that no large bubbles are allowed to form in the solution and are preferably .0059"
in ~ met~r. A heat exchanger 78 (shown in Fig. 5) is attached to the con-içn~çr 50 at port 80 to m~int~in the lelllpeldlule of the solution at less than 65C and preferably at 25 25C. A pH monitoring device (not shown) is ~tt~he~ to port 80 to measure the pH
of the solution and sodium hydroxide from reservoir 56 (shown in Fig. 5) is added to the condenser 50 intermittçntly as needed. The pH of the condenser should be m~int~ined in the range of 9 to 12 and is preferably at 10. The condenser 50 is sealed so that all of the unstable gaseous byproduct is forced to go through the sodium30 hydroxide solution and there is no exhaust pipe for any gases to escape.
The reacted sodium hydroxide solution is drawn off at a predetermined i-- WO 94/2L~29 21 5 ~ 5 ~ ~ PCT/CA94/00152 rate through the outflow 82. The rate that the liquid is drawn off is equivalent to the rate that liquid hydrocarbons are being produced in the condenser.
As shown in Fig. 4, the drawn off liquid is then processed by a reverse o.~mo~i~ se~aldlol 84 which se~aldtes the liquid into liquid hydrocarbons and reacted 5 sodium hydroxide solution. The liquid hydrocarbons are then removed as shown by arrow 86. Preferably the reverse osmosis se~)~r~or will be one which uses a cellulose membrane. The liquid hydrocarbons which are sep~ d in the reverse osmosis sep~dtor are then ready for reuse or separation by any conventional method.
The reacted sodium hydroxide solution is conducted to a ~ till~tion 10 chamber 54. Preferably the pipes 88 which conduct the reacted sodium hydroxide to the ~ till~tion chamber 54 are wound around the conduit 58 so that the reacted sodium hydroxide solution will cool the gases in conduit 58 while the gases will heat up the reacted sodium hydroxide solution in pipes 88. The reacted sodium hydroxide solution will be heated to less than its boiling point to minimi7e any precipitate 15 re~ ining in pipes 88. Preferably the reacted sodium hydroxide solution will be heated to 65C in the pipes. In the rli~till~tion chamber 54 the reacted sodium hydroxide solution is se~ ed into water having some carbonate and sodium chloride dissolved therein and salts, primarily sodium hydroxide. The (~i~tilled water can then be disposed of or used as required and it is removed as shown by arrow 90. The 20 salts, primarily sodium hydroxide, are stored in the reservoir 56 to be used as needed In the plcfellc;d emb~iml~-nt for input waste of 50% water, 18%
plastics, 25% hydrocarbons and 7% glass and metals in general the following occurs.
In the reactor 14 the waste is dissociated into water vapour, carbon monoxide, 25 chloride ion, carbon dioxide, hydrogen gas, small chain hydrocarbons and/or simple hydrocarbons, sulphur, nitrogen ions, carbon, char, glass and metals. In the catalytic condçn~çr the sodium hydroxide ~ oci~teS in water into sodium ion and hydroxide ion; the carbon dioxide dissolves in water; the chlorine ion combines with the sodium ion to form sodium chloride, the carbon monoxide and the small chain hydrocarbons 30 and/or simple hydrocarbons combine with the hydrogen ion and the hydroxide ion to form weak alcohols or weak acids and liquid hydrocarbons; the sulphur forms sulphur wo 94~21329 2 i S 8 ~ 5 ~ PCTICA94/00152 ~l based salts; the nil,ogen forms nitrogen based salts; and some of the sodium mayform sodium based salts. In the reverse osmosis sæ~ or the hydrocarbons are removed from the saline solutiom In the ~i~till~tion chamber water with minor amounts of weak hydloc~bons, carbonates and sodium chloride which were not 5 removed by the reverse osmosis unie is boiled off and then condensed; and a residue of salts, primarily sodium hydroxide, is stored in the reservoir.
It will be appreciated that the above description related to the plc;rell~d embodiment by way of example only. Many variations on the invention will be obvious to those knowledgeable in the field, and such obvious variations are within 10 the scope of the invention as described and cl~imP~, whether or not expressly described.
The process is for solid waste m~teri~l having, by mass, less than 80%
water. The process is specifically designP~I for biome~ l waste material which has a typical co,l,~osi~ion by mass of 50% water, 18% plastic, 25% hydrocarbons and 7%15 glass and metals. The process could also be used for the conversion of such things as tires. Some mol1ifir~tions of the process may be needed to adapt the process to other types of waste but these mo~lifir~tions are int~n-led to be within the scope of the invention and would be obvious to someone skilled in the art.
For in~t~nce, it will be appl~iated by someone skilled in the art that 20 the feed tube system could be modified to allow for alternate methods of feeding the waste material into the reactor and minimi7ing the amount of air that gets into the cli~till~tinn vessel.
Claims (22)
1. A process for converting solid waste comprising materials having long carbon chains and hydrogen groups and having by mass less than 80% water, the process comprising dissociating the solid waste substantially in the absence of oxygen to break at least some of the bonds in the long carbon chains to form gaseous byproducts containing carbon radicals and particulate matter, characterised in that the gaseous byproducts are unstable and the carbon radicals in the unstable gaseous byproducts are reacted with an aqueous solution containing a hydroxide or carbonate base to produce a solution containing at least some liquid hydrocarbons.
2. A conversion process according to claim 1 wherein the solid waste is dissociated at an energy level of at least 80 kcal/mole or a temperature of at least 800°C.
3. A conversion process according to claims 1 or 2 wherein the reacting step comprises the steps of spraying the unstable gaseous byproducts with the solution to form reacted gases and cooling the reacted gases.
4. A conversion process according to claim 3 wherein the cooling step comprises a first partially cooling step wherein the reacted gases are cooled to a temperature in the range of 100 °C to 85 °C, producing a first condensate and collecting the first condensate and a second partially cooling step wherein the remaining reacted gases are further cooled to a standard temperature and pressure, producing a second condensate and collecting the second condensate.
5. A conversion process according to any of claims 1 to 4 wherein the solution is a sodium hydroxide solution.
6. A conversion process according to any of claims 1 to 5 wherein the solid waste is dissociated at an energy level of at least 110 kcal/mole or a temperature of at least 1100°C to break at least some of the bonds in the hydrogen groups.
7. A conversion process according to claim 4 wherein the second cooling step comprises a plurality of partially cooling steps, each producing a condensate and collecting each condensate.
8. A conversion process according to claim 1 wherein the reacting step comprises the steps of partially cooling the unstable gaseous byproducts and maintaining the carbon radicals in their radical form so that long carbon chain gases do not form and condensing the partially cooled unstable gaseous byproducts in catalytic condenser containing the solution.
9. A conversion process according to claim 8 wherein the temperature of the solution in the catalytic condenser is maintained at a temperature less than about 65°C.
10. A conversion process according to claim 8 or 9 wherein the pH of the sodium hydroxide solution in the catalytic condenser is maintained between 9 and12.
11. A conversion process according to any preceding claim further including the step of separating the liquid hydrocarbons from the reacted solution.
12. A conversion process according to claim 1 1 further including the step of distilling the separated reacted solution into water and sodium hydroxide.
13. A conversion process according to claim 12 wherein the temperature of the solution in the catalytic condenser is maintained at a temperature of about 30°C.
14. A conversion process according to claim 13 wherein the pH of the sodium hydroxide solution in the catalytic condenser is maintained at about 10.
15. An apparatus for converting solid waste comprising material having long carbon chains and hydrogen groups, the apparatus comprising a sealed reaction vessel for treating the waste material substantially in the absence of oxygen and a feed system for transporting the waste substantially in the absence of oxygen into the reaction vessel, characterised in that the apparatus includes a condenser system downstream of the reaction vessel for reacting the gaseous byproducts with an aqueous solution containing a hydroxide or carbonate base to produce a solution containing at least some liquid hydrocarbons, and means for removal of particulate matter formed in the reaction vessel.
16. An apparatus as claimed in claim 15 wherein the condenser system comprises a sealed catalytic conversion chamber including a means for spraying the unstable gaseous byproducts with the solution to form reacted gases and a means for cooling the reacted gases.
17. An apparatus as claimed in claim 16 wherein the cooling means comprises a plurality of consecutive mist eliminators each for cooling the remaining reactedgases therein to a predetermined temperature range and producing a condensate.
18. An apparatus as claimed in claim 17 wherein the cooling means comprises a first and second mist eliminator and a conduit between the catalytic conversion chamber and the first mist eliminator and wherein the conduit is configured to so as to reduce the velocity of the reacted gases.
19. An apparatus as claimed in claim 15 wherein the condenser system comprises a means for partially cooling the unstable gaseous byproducts and maintaining the carbon radicals in their radical form so that long carbon chain gases do not form and a catalytic condenser downstream of the partially means the catalytic condenser containing the solution for condensing the partially cooled unstable gaseous byproducts.
20. An apparatus as claimed in claim 19 further including a separator for separating the liquid hydrocarbons from the reacted solution.
21. An apparatus as claimed in claim 20 further including a distillation unit for distilling the separated reacted solution into water and sodium hydroxide.
22. An apparatus as claimed in claim 21 wherein the separator is a reverse osmosis separator.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US3332493A | 1993-03-18 | 1993-03-18 | |
| US08/033,324 | 1993-03-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2158553A1 true CA2158553A1 (en) | 1994-09-29 |
Family
ID=21869751
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2158553 Abandoned CA2158553A1 (en) | 1993-03-18 | 1994-03-18 | Solid waste conversion process and apparatus |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU6200494A (en) |
| CA (1) | CA2158553A1 (en) |
| WO (1) | WO1994021329A1 (en) |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3725584A1 (en) * | 1987-08-01 | 1989-02-16 | Helmut Zink | Pyrolysis of polymer articles - in a two-drum reactor followed by treatment in a scrubber and an post combustion unit |
| DE3733078C2 (en) * | 1987-09-30 | 1996-10-02 | Siemens Ag | Thermal waste disposal plant |
| DE3820317A1 (en) * | 1988-06-15 | 1989-12-21 | Christian O Schoen | Process for separating flowable organic media containing harmful or polluting constituents |
| AU5207990A (en) * | 1989-04-10 | 1990-10-18 | 655901 Ontario Inc. | Process for the destruction of organic waste material |
| US4934286A (en) * | 1989-08-24 | 1990-06-19 | Fowler Benjamin P | Apparatus and method for the disposal of waste |
| AU6506690A (en) * | 1989-09-29 | 1991-04-28 | Product Control Limited | Method and apparatus for refinement or treatment of material |
| DE3933809A1 (en) * | 1989-10-10 | 1991-04-18 | Pyrolyse Kraftanlagen Pka | METHOD FOR DISPOSAL OF WASTE |
-
1994
- 1994-03-18 CA CA 2158553 patent/CA2158553A1/en not_active Abandoned
- 1994-03-18 AU AU62004/94A patent/AU6200494A/en not_active Abandoned
- 1994-03-18 WO PCT/CA1994/000152 patent/WO1994021329A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| WO1994021329A1 (en) | 1994-09-29 |
| AU6200494A (en) | 1994-10-11 |
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