CA2703446A1 - Overcoming hazardous material problems by recycling techniques - Google Patents

Abstract

New process and equipment have been introduced whereby environmental waste hazardous material namely household garbage, electronic wastes and steel scrap leftovers are processed in a way that CO, H2; CH4 and H2 and electricity are produced.
Impurities in the solid phase are removed and properly disposed.
Hydrogen is used for processing of scraps in stairway filtering bottom inclined furnace. Hydrogen atmosphere is kept in the furnace and furnace is heated in gradual manner from a temperature of 150C to 1500C.
Plastics are separated first alone and plastic with metals up to Sn melting point and then metal along with two or more metals are produced. These are separated by phase separation techniques outside the furnace. Ashes from garbage or coal gasification are fractionated and individual oxides are separated by chemical and heavy media separation.
There are no residue to environment and no emission of gases except CO2

Description

Overcoming Hazardous Material Problems by Recycling Techniques Environmental hazardous material consist mainly House hold garbage, Electronic waste, and steel scrap left over. House hold Garbage is in greatest tonnage.
Lead batteries and car tires can be included in above mentioned second category Garbage material is composed of hydrocarbons, carbohydrates, metals and non-metals, glass and ceramics, many diversified materials along with various percentages of water and air.

When metals and non metals along with glass and ceramics are removed, garbage contains various percentage of C, H, 0, N, S, P, Cl and ash forming ingredients.

Ash is a metallic residue which actually contained as complex compounds in cellulose and is left over when cellulosic; a plastic type material is burnt over.

An ash material contains oxides like Si02 (mainly), CaO, FeO, MnO, CrO, NiO, TiO2, CuO and alkali oxides. Some of these oxides may be in traces.

When C, H, N, S, P etc are gasified under reducing conditions, metals in ash are left over as oxides , which can be fractioned to individual oxides as Si02, CaO, FeO, MnO etc. Impurities in the gases like H2S, PH 3, Cl, NxO are removed and gainfully disposed. Remaining gases are high reduction gases CO, H2 (here after referred as syn gases). The sensible heat in these gases may be recovered as steam in heat exchanger or circulating inert gases (He, N2). Steam may be used in electricity production or saved to be latter used in shift reaction Electricity may be used by inert gases in gas turbines.
Steam is used in continuous manner.
Steam + CO + H2 - H2 + some remaining CO + CO2 exothermic Steam + CO + H2- (2nd step catalyst) H2+ CO2 exothermic CO2 is removed and gainfully marketed.

CO + H2 are obtained appropriate stichiometric ratios and it is made to undergo Methenation reaction.

CO + H2 - (nickel catalyst) CH4 + H2O + Heat Heat is used for generation of electricity, H2 0 is removed.

This reaction holds large prospect for generation of automobile fuel and is gainfully promoted.

I have so far discussed garbage as a constant composition material. Garbage has high variable composition particularly in water content. It varies in chemical composition depending on geographical and seasonal factors.

The CO H2 gases after impurities and heat removal at about 300-400C go to heat exchanger where moisture from garbage is removed. Exit gas CO,H2 are made to exit at 50-75C when sent to market. When these gases are to go to shift reaction these are cooled to only 300 C
Garbage is deprived of its major water contents and exit garbage going to high temperature reactor to react it with preheated or normal oxygen. The temperature of the exit gases from high temperature reactor is controlled by the control of moisture in the garbage charge or by in put of CO2 Temperature of exit product gases which are as reducing gas can be made to reach 11000. By performing high temperature reaction high hydrocarbon like CH4, C21-16 are not formed.
Coal is similar in composition to garbage after metals; ceramics and glass have been removed from it.
Coal seams have water 30-40%. Where it is dried to approx. 10% it mainly varies from garbage in sulphur content and has high ash content up to 15%. Garbage has low sulphur and low ash contents.
A high quality coal with ash up to 5% and sulphur 1.5% has approximately following composition by weight.
C- 72-78%; H- 2-2.5%;0 --4%;N- 2%
We can mix garbage and coal is a judicious ratio if so required.
When H2 is only produced and CO2 is marketed, H2 is used in a second type garbage plant that is processing of electronic garbage for removing and fractionation various plastic.

Ethylene and Chlorofluoroethylenes Polycarbonates, Poly- imides type polyethylene Poly type of plastics which Nylons, PET these of plastics which vinyl melting higher than are relatively high may melting at chloride(PVC) 200 but less than 250 melting plastics 500C or more these Polypropylene (PP) C which will melt will melt with Zn.
all those plastic with first melting melting up to 200C metals Sri, Se 300-Removing and processing of melts are in the following sequence: Sri .,, 232C,Pb 328C,Zn .., 420C,Al- 660C,Cu -1083C,Fe - 1534C

Remaining is Fe + Glass + Ceramic, where Fe is magnetically picked up.
These days many different metals are used in coatings, soldering, welding, and brazing.
These will be mostly going with Pb or Cu.

Plastic may be separated further by density means.

Polyethylene is the lightest, PVC is next heavy, and Fluro-chloro-hydrocarbons are heavier than PVC.
More effort is required to separate PET, nylons, polycarbonates.

Temperature of the staircase furnace is increased gradually by electric heaters.
Hydrogen is blown upward through refractory filters so that these are not plugged.
Hydrogen is drawn from upper floor; it is cooled to condense any volatile metals and recycled after external heating and adding some made up hydrogen.
Hydrogen atmosphere is required to save Zn, Al from oxidation with CO.

When iron is finally collected in exchanging holders it is cooled under Hydrogen.
The exit material is separated by electromagnetic and transported.

Electronic material has Silicon chips which will melt in the same range as Ni, Co but due to low density as compared to Ni will go along steel, when cooled it will separate with glass.

Germanium is also used as chip material it will melt and join with melted copper where it will be removed from copper by electrolytic techniques. In electronic scraps we have new soldering alloys new brazing alloys, new circuit material. All these join with Pb fraction or copper fraction.

The third type of scrap is left over scraps when prime quality material is separated by visual techniques. Left over scrap is paints + colour materials in paints, steel pieces and all other metallic ingredients.

Separation of Garbage and Coal Ash into Individual Oxide Coal and garbage ash will consist of SiO2, CaO, FeO, A1203, Mn02, Cr2 O3,TiO2 and alkali oxides.

These are reacted with Na2CO3 at temperatures of approximately 13000 and burnt material dropped into water tank. Water solution is filtered.
Na2SiO3, NaA1O2, NaCr2O3 being water soluble will separate. CaSi03, NaFe02 are again put into water and CO2 is passed Fe304 formed will be separated by wet magnetic separators. Na2SiO3, NaCrO4, NaA1O2 are changed to pure A12O3 by calcium desiliconization. Some other sodium salt like CuO, ZnO, and Mn02 are also formed.
These are discharged from the bottom of the cyclone separator in the step separating Cat Si03. These mixtures go to a heavy media separator when CO2 is also introduced.
Magnetic fractions FeO, MnO, CrO are separated by wet magnetic separator.

Some residue material settles at the bottom of magnetic separator. It will be mainly ZnO, CuO, TiO2, and NiO. These will be treated by acetic acid, HCl to make these water soluble and used as micro nutrients in fields.
Phase separations:

When two metals or more than two metals separate together and they are soluble together, they can be separated to individual metals by different densities vaporization or different phase formation. When one phases namely oxide phase is lighter and float on the surface then floating phase can be made stable by external additions like CaO, NaOH.
Table 1 Metals, metal oxide density g/cu.m melting point c boiling point C
Al 2.3 660 2529 A1203 3.95 2072 2977 Cu 8.94 1084 2562 CuO 6.31 1201 2000 Cr 6.3 1807 2671 Cr2O3 5.22 2435 4000 Fe 7.87 1538 2862 FeO 5.7 1378 Fe304 5.2 More than 1700 Decomposes Ge 5.6 938 2833 GeO 4.28 400 1200 Mn 5.95 1246 2061 MnO 5.37 1945 ----Sri 6.94 231 2602 SnO 6.45 1080 Ni 7.81 1453 2732 NiO 6.67 1955 ---Pb 10.66 327 1749 PbO 9.64 888 1477 Zn 7.57 419 907 ZnO 5.6 1975 Decomposes Iron which dissolves Mn, Cr, Ni, C, Si can be made as interstitial free metal by melting and passing oxygen.
Fe Mn - MnO,Cr + 0 - CrO,Ni - NiO, C - CO,S - SO2 In the following is shown some preferred embodiment of gasification of garbage.
If the situation is that only garbage disposal is required then the end product are CO,H2 (synthetic gas) and electricity.

If it is desired to produce artificial natural gas The steam produced and Hot CO,H2 are reacted over shift catalyst and also the ratio are 3mole H2 and One mole CO.
The gases are then passed over Methenation catalyst with heat removal from the catalyst bed the product is synthetic natural gaseCH4. ) Also significant amount of electricity is produced.
This approach could be desirable in areas where natural gas is used as automobile fuels.
The shift conversion may be carried that H2 is only end product (apart from minor impurities This H2 is used as protective media in the electronic garbage or other steel left over garbage.

If the plant is a complex producing all these items their relative production can be adjusted for maximum profitability.
In the following I describe labelled production facilities of all these plants and processes.
Figure 1 Explanatory Labels on garbage Processing plant.
L Garbage trucks discharging into a garbage pit 2. Elevating conveyor charging into a magnetic separator. 3.
3. Wet magnetic separator.
4. 5. Metal carrying conveyors. Non magnetic metals are hand picked and deposited ion these conveyor, which carry to common metals conveyor to metal processing plant.
6. Hand picked glass and ceramic to a carrier to disposal place.
7. Cardboard and paper going to a truck.
8. Elevating conveyor carrying remaining material to a hopper 9. Controlled speed screw carrying material to a large size hopper. This hopper has heat exchangers pipes inside which vaporize water from the garbage and cool down the exit CO, H2 gas.
10. Water from garbage is de-odorized before leaving to the some other use.
11. 12. Controlled charging and discharging from large size hopper 13.
14. Screw extruding to a high temperature reactor. Where charge is reacted with oxygen. Both charge and oxygen are in approximate stichiometric ratio 15. A high temperature reactor is a steel shell with refractory lining.
In the lower half are tuyeres for oxygen input. These tuyeres can be ordinary water-cooled tuyeres or plasma tuyeres for oxygen heating.
15. Nearby is oxygen plant supplying oxygen to high temperature reactor.
16. Oxygen plant is pressure swing absorbing type due to investment capital treason. Other wise cryogenic plant would have been better.
17 At the top of high temperature reactor is top refractory lined pipe.
18 This carries the gases to high temperature impurities removing arrangement. Here S, P, Cl, NxO. Are removed these gases are further led to heat removal by 1. Steam production. 2. By circulating gases 19 The gases CO, H2 go to garbage hopper for moisture removal.

Garbage charge can be gasified to CO, H2, H2S, PH3, HCI, and NxO. At temperature of 1100 C H4,C2H6 are not formed.

Figure 2. Shift gas reactions carrying over system connected with hot Potassium carbonate removal Of C02, H2S.
1 Purified gases CO, H2 ait about 300 C an steam are brought from plant of Figure 1.
Gaseous composition at various point are shown in attached table on figure 2.
Table 1.
Typical 1 2 3 4 operating conditions N2+ CH4+ Bal. Bal Bal Bal Others H20/Drry gas 0.6-1 .47-0.8 .46 .81 ratio Temperature 650-700 765-810 420-465 450-500 Pressure PSIG 200 400 200-400 200-400 200-400 Figure 3. Simplified flow diagram of carrying out Methenation reaction, between CO
and H2.
1 H2 and CO ratio for Methenation reaction are produced in the gas shifting reaction.
2. The formation of CH4 and H2O is highly exothermic reaction and catalyst cooling is required here it is done by circulating N2 after cooling in a gas turbine electricity generation reaction.
Three Methenation reactors are shown feed one gas turbine 20 CO + 60H2 =20CH4 + 20 H2O
From 3 tons of coal we get about 3x20 kg.mole CH4 and 1.44 MW electricity Figure 4. Separating of metal and plastics from electronic garbage Shown is slanting stair case furnace with internally heated electric means, a positive hydrogen atmosphere is kept in the furnace.
1.Double lock charging system either a conventional double bell system or when charge is relatively large size a double plate sliding system Cut car body in four pieces.
2.Steel shell with refractory lining, a refractory filter is at the bottom.
Furnace is sliding downward with stairways. Melt collectors one before the stair step and one after the step after the charge have tumbled down. Both melt collector are joined 3.A charge pusher at every step 4.A hydrogen circulation system to collect volatile metals, and reuse the hydrogen after heating.

5.Charge cooling circulating hydrogen system 6Magnetic separation of iron.
7 Plastic melts are collected in separate filter collectors.
8 Refractory filter and collector.
9 Collectors for volatile metals 1OManetic separator 11 Hydrogen cooling of iron Figure 5. Separation of a metal mixture when it has separated together in a step. It is an illustrative example.
Separation of Sri, Pb, Zn, Cu, 1. The mixture is heated and Zn will be volatized.
2. The remaining mixture is transferred in an other vessel Oxidizing gases mixture is blown and charge is heated PbO is volatilized.

3. Cu with noble metals in it is cooled Cu and noble metal are solidified.
4. Sn remain as liquid.

Figure 6. Refractory filter.
Upper layer and lower layers are refractory plates with small whole in these.
The hole size could be 1mm. Embedded between is a steel wire Gauze of 300 mesh.
Below this filter plate may be bricks with large size holes for support.
Figure7.
Figure shows how to cast to desired film or shape.
Shown is a piston and cylinder of high strength steel with refractory lining inside.
There is inlet for the melt. The melt may be liquid metal plus some slag, metal and plastic, metal only. On the extrusion side is a water cooled die of required configuration.
Flat or H shape. When the piston closes the inlet hole every thing is enclosed inside. The extruded metal with a thin coating travels on a floor for cooling.
From earlir basic consideration and preferred practical designs following summarized conclusions may be drawn:

1) I have invented series of unit process leading to comprehensive process for the gainful utilization of hazardous waste, namely household garbage, electronic waste and steel scrap leftover.
2) Whereby high energy, high temperature syn gases (CO, H2) are produced which can be directly used for other purposes; that the sensible heat energy is taken away from these gases by creation of steam, by heating of circulating gases or by heating of charge material. By way of heat exchangers.
3) Where these high energy gases themselves can be used as source of energy by way of combustion, by reaction with other gases and materials.
4) Where syn gases and steam produced in single or multiple nuits can be made to undergo shift reactions by passing over catalysts. When gases compositions is H2, CO2 this can be separated to pure H2 and CO2. when it is H2 CO CO2 it can be separated into H2 CO and CO2.where by H2 and CO can be formed in desired ratios.
5) Where a appropriately adjusted ratio of H2 and CO and by passing over a catalyst and cooling the catalyst internally by circulating gases like He and N2 electricity can be produced with simultaneous production of CH4 and H2O (Methenation) where H2O is removed and dried CH4 is normal methane gas.

6) When H2 is the only reaction product it is lead to electronic garbage processing plant. Where H2 is preheated or otherwise is used to separate plastics and metals from each others.

7) Plastics up to certain type are separated as individual type polyethylenes from polyvinyl chloride and Flourochloro type plastic. High melting range plastics will melt along with metals.

8) Whereby plastics will be melted and drained up to certain range, there after melting range of plastics and metal may over lap and they will drain together.
Heat is provided by electric heaters inside the staircase furnace. Hydrogen atmosphere and circulation kept inside the furnace to save any metal from compound formation ZnO, A1203, A13C. After separation of Ni and Co as a one group steal falls into an alternative holding hopper vessels where it is cooled to room temperature. Steel along with glass, silicon, and ceramic is discharged on a conveyor and magnetically separated to fall into separate containers.

9) Whereby hydrogen is used counter current and is recycled to keep the filters pore open. Where the refractory filter is a thin refractory plate with small holes and fine steel wire gauge is embedded between these plates.

10) When more than one metal separate to gather these are separated by density means, vaporization, phase separation and conventional electrolysis processes.

11) where by moisture in the garbage is adjusted to obtain a desired temperature of the product gases. Where as instead of moisture CO2 may be introduced.
Explanatory Notes:
When good quality steel material is separated by hand picking, a material is left which is mixture of metals and plastics. It is steel scrap left over.
Electronic waste is synonymous with electronic garbage.
Stair case furnace is a slanting down ward refractory line furnace where steps are made to slide downward and tumbles to separate the melted material. Furnace is under atmosphere of hydrogen gas.
Stichiometric According to a chemical formula Heavy media separation. Separation in a media which approximately floats the constituents.

Claims (11)

1. I have invented series of unit processes leading to comprehensive process for the gainful utilization of hazardous waste, namely household garbage, electronic waste and steel scrap leftover.

2.Whereby high energy, high temperature syn gases (CO, H2) are produced which can be directly used for other purposes; that the sensible heat energy is taken away from these gases by creation of steam, by heating of circulating gases or by heating of charge material by way of heat exchangers.

3. Where these high energy gases themselves can be used as source of energy by way of combustion, by reaction with other gases and materials.

4. Where syn gases and steam produced in single or multiple units can be made to undergo shift reactions by passing over catalysts. When gases composition is H2, CO2 this can be separated to pure H2 and CO2. When it is H2 CO CO2 it can be separated into H2 CO and CO2.where by H2 and CO can be formed in desired ratios.

5.Where a appropriately adjusted ratio of H2 and CO and by passing over a catalyst and cooling the catalyst internally by circulating gases like He and N2 electricity can be produced with simultaneous production of CH4 and H2O (Methenation) where H2O is removed and dried CH4 is normal methane gas.

6. When H2 is the only reaction product it is lead to electronic garbage processing plant. Where H2 is preheated or otherwise is used to separate plastics and metals from each others.

7. Plastics up to certain type are separated as individual type polyethylenes from polyvinyl chloride and Flourochloro type plastic. High melting range plastics will melt along with metals.

8.Whereby plastics will be melted and drained up to certain range, there after melting range of plastics and metal may over lap and they will drain together. Heat is provided by electric heaters inside the staircase furnace. Hydrogen atmosphere and circulation kept inside the furnace to save any metal from compound formation like ZnO, A12O3, A13C. After separation of Ni and Co as a one group steal falls into an alternative holding hopper vessels where it is cooled to room temperature.
Steel along with glass, silicon, and ceramic is discharged on a conveyor and magnetically separated to fall into separate containers.

9.Whereby hydrogen is used counter current and is recycled to keep the filters pore open. Where the refractory filter is a thin refractory plate with small holes and fine steel wire gauge is embedded between these plates.

10.When more than one metal separate to gather these are separated by density means, vaporization, phase separation and conventional electrolysis processes.

11.Where by moisture in the garbage is adjusted to obtain a desired temperature of the product gases. Where in instead of moisture CO2 may be introduced.