Process and equipment for high-speed recycling and treatment of organic wastes and generation of organic fertilizer thereby
10919817 ยท 2021-02-16
Inventors
Cpc classification
C05G3/90
CHEMISTRY; METALLURGY
Y02P20/145
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B09B3/40
PERFORMING OPERATIONS; TRANSPORTING
C05G3/60
CHEMISTRY; METALLURGY
Y02W30/40
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
C05F17/50
CHEMISTRY; METALLURGY
International classification
C05G3/60
CHEMISTRY; METALLURGY
A01G24/60
HUMAN NECESSITIES
C05F17/50
CHEMISTRY; METALLURGY
Abstract
Methods and equipment for high-speed production and improving quality of liquid and solid organic fertilizers from organic solid wastes by (1) pre-treatment system, for purification, size reduction, and slurry generation, (2) HiSAP recycling system using slurry generated to form soluble compounds of easily degradable organics, and insoluble compounds of moderately degradable organics of mainly lignocellulosic materials, and production of organic radicals, reactive oxygen species including superoxygen, hydroperoxyl radical, hydrogen peroxide, and hydroxyl radical to thermally decomposing easily degradable organic and curing remaining compounds therein, and (3) product refining system to produce organic fertilizers, to enhance 7 major functions and capabilities including moisture absorption and holding, nutrients adsorption and holding, soil particles holding and conserving, soil air ventilation, soil water transmission, soil thermal insulation, and generation of plant growth stimulation agents, and pollution elimination as sterilizing pathogens and parasites, detoxicating toxic organics, and removing heavy metals therefrom.
Claims
1. A method for producing organic fertilizers from organic solid waste material, comprising (1) pre-treating waste material, the pretreatment further comprising the steps of storing the waste material comprising one or mixtures of municipal solid wastes, restaurant wastes, gardening wastes, agricultural wastes, and dead animals, mechanically pretreating the waste material, wet pulping the stored waste material, recovering metals, glass, sands, bones, and plastics from the mechanically pretreated and wet pulped waste material, recovering wet pulps and food slurries from the mechanically pretreated and wet pulped waste material and forming wet pulps and food slurries, and storing the wet pulps and food slurries in a storage tank; (2) stabilizing and activating the wet pulps and food slurries and organic waste material that do not need pretreatment, the organic waste material that do not need pretreatment comprising one or mixtures of sludge, animal wastes, night soils, anaerobic digesting residues, and landfill leachates, by mixing and adjusting temperature and moisture in the wet pulps and food slurries and the organic waste material that do not need pretreatments to obtain mixed and adjusted organic waste material, multi-conditioning the mixed and adjusted organic waste material to obtain multi-conditioned organic waste material, wherein the mixed and adjusted organic waste material are treated for solubilization and destruction of easily degradable organics, loosening of lignocellulose fibers, sterilization of pathogens, destruction of weed seeds, dissolution of heavy metals, and conditioning for organic radical generation, waste curing the multi-conditioned organic waste material to obtain cured organic waste material, wherein the multi-conditioned organic waste material are treated for release of nutrients, generation of heat energy, destruction of toxic organics, generation of humic substances, and plant-grow-stimulating agents, and dewatering the cured organic waste material, wherein solid and liquid contents in the organic waste material are separated, to generate solid and liquid organic fertilizers, and (3) refining the solid and liquid organic fertilizers, the refining process further comprising the steps of activating and steam exploding, and nutrients adjustments of solid fertilizers, and concentrating, catalytic oxidizing and nutrient adjustments of liquid fertilizers, wherein refined organic solid and liquid fertilizers are generated.
2. The method for producing organic fertilizers from organic solid waste material as described in claim 1, wherein the stored organic waste material are the municipal solid wastes, and the stored municipal solid wastes are treated with the wet pulping and separation step; wherein the municipal solid wastes are processed to particles at a particle range of 3 to 5 cm and particles at a particle size of less than 1 cm and are further processed in a wet pulping and separation apparatus having multiple compartments for multiple material removal, wherein metals are removed and recovered in a first compartment of the wet pulping and separation apparatus based on specific gravity in a range of greater than 3; rocks, sands, and glasses are removed and recovered in a second compartment of the wet pulping and separation apparatus based on specific gravity in a range of 2 to 3; bones are removed and recovered in a third compartment of the wet pulping and separation apparatus based on specific gravity in a range of 1.3 to 2; and plastic materials and pulps and slurry material are recovered in a fourth compartment of the wet pulping and separation apparatus based on specific gravity in a range of less than 1.3, and wet pulps and food slurries are further separated from the plastic materials by a moving screen device with openings in a size of approximately 1 to 1.5 cm attached to the end of the wet pulping and separation apparatus.
3. The method for producing organic fertilizers from organic waste material as described in claim 1, wherein a multi-conditioning reactor is used for the multi-conditioning step and for thermal solubilization of protein, fats, starch, and toxic organic compounds in the waste, leaving lignin and celluloses in particulate forms, destroying pathogens and weed seeds, dissolving metals, and generating organic radicals through chain reactions to further breakdown organics, and the multi-conditioning reactor is operated under conditions of controlling in a reducing environment with negative redox potentials, pretreating incoming wastes by solubilizing easily decomposable organics by thermal hydrolysis and liquefaction; and generating organic radicals and promoting chain reactions; and increasing temperature to a range of 140 to 180 C. by heat-pipe heat-exchange devices before entering the multi-conditioning reactor by using heat generated from the waste curing step; maintaining pressure at the related saturated steam pressures; and adjusting retention time of the multi-conditioning reactor at a range from a few minutes to about 2 hours.
4. The method for producing organic fertilizers from organic solid waste material as described in claim 1, wherein the multi-conditioned organic waste material are cured in a curing reactor in presence of reactive oxygen species (ROS) to obtain cured organic waste material, the curing reactor comprises cathodes and anodes, wherein the ROS comprises superoxide, hydroperoxyl radical, hydrogen peroxide, and hydroxyl radical the multi-conditioned waste material are distributed to the curing reactor through a plurality of high pressure input nozzles to generate turbulent flows and creating cavitation effects by forming micro bubbles; the ROS are created by contacting by dissolved oxygen with electron from the cathodes and hydrogen ion from the anodes in the curing reactor; enhancing the ROS generation by Fenton Reactions with a vertical cylindrical catalyst device arranged in cylindrical shape with flow distributing and contacting catalyst opportunity in the curing reactor; providing about of oxygen needs by a series of multiple anodes arranged along inside wall of the curing reactor with semiconductor electrodes; forming of organic radicals and through chain reactions to continuously decompose soluble forms of organics to assist in curing of organics and generation of plant-growth stimulating-agents; maintaining temperature range at room temperature to 210 C.; maintaining the minimum pressure of the reactor to 0.5 MPa beyond the saturation pressure of steam formation in the curing reactor to increase ROS levels and keep the curing reactor cost-effective; and decomposing soluble organics by reactions of hydrogen abstraction, redox reaction, electrophilic addition, and thermal cracking.
5. The method for producing organic fertilizers from organic solid waste material as described in claim 1, further comprising removing heavy metal from the solid and liquid organic fertilizers after the dewatering step and before the refining process by solubilization and ion exchange.
6. The method for producing organic fertilizers from organic solid waste material as described in claim 1, wherein a product refining system is used in the refining process to generate solid and liquid organic fertilizers without presence of microorganisms to avoid species invasion, or to treat the fertilizer products by adding beneficial bacteria or microorganisms.
7. The method for producing organic fertilizers from organic solid waste material as described in claim 1, wherein the organic fertilizers are refined solid organic fertilizers comprising pelletized solid organic fertilizer, powdered solid fertilizer, pelletized solid humic fertilizer, powdered solid humic fertilizer, and biosolid fertilizer.
8. The method for producing organic fertilizers from organic solid waste material as described in claim 1, wherein the organic fertilizers are refined liquid organic fertilizers comprising liquid fertilizer, concentrated liquid fertilizer, bio-liquid fertilizer, and concentrated liquid humic fertilizer.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention will be described in more detail by way of example only, with reference to the accompanying drawings. The following drawings are provided:
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DETAILED DESCRIPTION OF THE INVENTION
(11) 1. Basic Treatment Principles, Operational Procedures and Objectives
(12) By solving the above-mentioned problems associated with the existing processes, the present invention uses Reactive Oxygen Species (ROS), including hydroxyl radicals, singlet oxygen, superoxide, and hydrogen peroxide generated directly from water in the reactors as oxidants to decompose Readily Degradable Organics. Part of the Readily Degradable Organics can be also degraded by various organic radicals produced in the thermal reactors of the subject invention design through chain reactions. Detailed descriptions of the ROS generation, reactions of ROS with organics, chain reactions of organic radicals are provided as follows.
(13) Major operation procedures and their objectives for the present invention is shown in the block flow diagram in
(14) As shown in
(15) The next step, Mechanical Pretreatment, is provided for further purification of incoming wastes and for shredding and grinding. This Mechanical Pretreatment operation also provides mixing function to homogenize waste contents and for blending of more than one type of waste, and/or for addition and mixing of other additives into the treatment system. The type of equipment used in the present invention will turn the waste stream into slurry/pulps by the Mechanical Pretreatment operation. Organic wastes including agricultural wastes, dead animals, and green wastes (gardening wastes) may require pretreatment of shredding and grinding operations. These wastes may be mixed with the MSW and treated together or grinded into fine particles (usually less than 2 to 3 mm) and delivered directly to the Eco-Waste storage tank as discussed below. The wet processing method will be further discussed, infra. The above operations together are considered as the Pretreatment Operations. Wastes such as sludge, human night soils, animal wastes, landfill leachates, and other high organic contents wastes with fine particles can be pumped to the Eco-Waste storage tank directly without the need for pretreatments.
(16) Result of the above Pretreatment Operation system will produce Eco-Waste slurries suitable for the next system called HiSAP in the present invention. Major unit processes of HiSAP Operation start with a Physical-Chemical Pretreatment, as shown in
(17) The next operation procedure will be the Multi-Conditioning Operation (also called Thermal Operation) which is performed with the following objectives: (1) Solubilization (hydrolysis) of Easily Degradable Organics, (2) Loosening of lignocelluloses fibers, (3) Sterilization of pathogens, (4) Destruction of weed seeds, (5) Pretreatment of heavy metals, and (6) Pre-Conditioning for ROS treatment and generation of organic radicals.
(18) Following the Multi-Conditioning Operation, the Curing Operation is provided. This step is the most important steps in HiSAP operation. At least the following seven objectives can be achieved by the Curing Operation: (1) Destruction of Easily Degradable Organics, (2) Release of nutrients (include all major N, P, K nutrients, medium-amount nutrients of Ca, Mg, S, and minor nutrients of Fe, B, Mn, Cu, Zn, Mo, Cl, etc.) from waste materials, (3) Generation and provision of heat energy, (4) Sterilization of pathogens, (5) Destruction of toxic organics, (6) Generation of humic and fluvic acids and other plant stimulating agents for growing, and (7) Pretreatment of heavy metals.
(19) After Curing Operation, most of the Easily Degradable Organics, toxic organics, and other nuisances (such as odor, weed seeds, pathogens) are removed. The remaining materials after Curing Operation are mostly lignin and celluloses which are subject to a dewatering operation, to generate both solid and liquid organic fertilizers. In order to enhance quality of products, or to produce special commercial organic fertilizers, product refining processes are selected after the HiSAP system. For the enhancement of solid organic fertilizers generated, the Activation Operation is provided. The Activation Operation is for the increase and strengthen of solid fertilizer functions, such as improvement of adsorption/absorption capabilities, increase of humic substances contents, adjustment of moisture contents, and adjustment of nutrient contents.
(20) After the Activation Operation, a wide variety of solid organic fertilizers can be produced. For the enhancement of liquid organic fertilizers generated, a series of concentration, catalytic oxidation for humic substances generation, and addition of indigenous microorganisms can be practiced producing various types of liquid organic fertilizers.
(21) 2. Processes and Equipment Involved in the Overall Recycling System
(22) Based on operation principles, objectives and procedures as discussed above, detailed recycling unit processes of an overall recycling plant are further delineated in
(23) Different recycling/separation processes are selected in the pretreatment system according to different types of incoming wastes to be treated. In the pretreatment system, MSW and biosolids wastes are two extremes: MSW requires most extensive unit processes for pretreatment, but biosolids almost don't need any pretreatment system.
(24) As shown in
(25) If the large objects are inorganic in nature (such as discarded refrigerators and other appliances) they are stored in area 8 for off-plant recycling. For the large organic objects (such as wooden furniture, textiles objects) are stored in area 9. The large wooden objects are delivered to a series of shredder and grinder 10 to reduce the particle sizes to less than 1 mm and deliver to the Wet Separation Control Tank 6. Other large objects are delivered to outside recycling facilities. Emissions collected from the receiving sump 3 area are send to a conventional air pollution control device for treatment. Wastes in the receiving sump 3 is processed through a large plastic Bag Breaker 4 to reduce sizes to less than 10 cm, and then continue using a shredder 5 to reduce sizes to approximately 3 to 5 cm (note: sizes too small could affect the separation of plastic and paper/wood pulps in the following process). The size separation processes can be controlled by screens adjusting to desirable openings, such as using multiple rotary screens (trommels) or vibration screens to obtain particles in the 3 to 5 cm, less than 3 cm, and greater than 5 cm ranges for different subsequent processing. The less than 3 cm fraction usually contains very small amount of plastics and can be further shredded/grinded to less than 1 cm and deliver to the Wet Separation Control Tank 6. The greater than 5 cm fraction can be further shredded to 3 to 5 cm range and send to the Wet Separation Control Tank 6 for the Wet Pulping and Separation Apparatus 11 for plastic removal and pulp/slurry generation.
(26) The Wet Separation Control Tank 6 is provided for equalization, moisture adjustment and mixing. The Wet Pulping and Separation Apparatus 11 is a wet separation device including at least five compartments, as shown in
(27) The unit processes involved in the HiSAP Recycling System (Plant) of the present invention is shown in
(28) Other wastes such as agricultural waste and animal wastes also can be treated together but may require pretreatment mainly for size reduction to about <5 mm sizes, preferably <2 mm, most preferably <1 mm, and mixed in tank 23. Wastes in tank 23 are moisture adjusted to about 85 to 90%, mixed and pre-heated to about 80 to 90 C. and then deliver to a heat exchanger 27 to further increase temperature to >140 C. when possible before entering into the Multi-Conditioning Reactor (or called Thermal Reactor) 24.
(29) The temperature in Reactor 24 is adjusted to approximately 140 to 180 C. by the heat-pipe heat exchangers and a conventional heater 803, when necessary. Pressure of the Multi-Conditioning Reactor 24 is the related saturated steam pressure corresponding to the water temperature in the Reactor. After reactions proceeded in Reactor 24 (principles and apparatus to be further discussed later) the material is then pumped through another two heat exchangers 26 and 28.
(30) The heat exchanger 26 is a liquid-liquid heat exchanger, which the higher temperature fluid is from the Curing Reactor 25. The heat exchanger 28 is a liquid-gas heat exchanger, where the higher temperature gas (steam) is from the gas phase of Curing Reactor 25. Heat Pipe heat exchangers are provided for both liquid-liquid, and liquid-steam heat exchange to maximize energy recovery.
(31) The pre-heated material by the two heat exchangers as discussed above is then pumped to the Curing Reactor 25 for reaction. The most favorable temperature range of the Curing Reactor is 190 to 210 C., depending on types of wastes treated. Wastes containing more quantity of Easily Degradable Organics favor lower range of the above temperature range. The pressure of the Curing Reactors 25 are controlled at 3 to 3.5 MPa, although no upper limits are required. The treated material from the Curing Reactor 25 is then pumped through heat exchangers 26 and 27 for energy recovery. The remaining heat in the treated material is recovered in the Physico-Chemical Reactor 23 by a coiled pipe. This cooled material is then pumped to an Equalization Tank 30 for temporary storage waiting for dewatering by a pressurized filtration unit 31.
(32) If heavy metal concentrations are too high (higher than the regulation limits for fertilizer products), the cooled material can be treated by a Three-Step Metal Extraction and Removal Method: The first step is used when the heavy metal concentrations are not significantly high (means, usually less than 100% beyond the legal limits of heavy metal concentrations in the finished fertilizer products). This first step can be automatically achieved by the Multi-Conditioning Reactor 24 and Curing Reactor 25 to solubilize metals due to the low pH (usually in the range of 4 to 5) generated in these Reactors. The solubilized metals in the liquid fraction of the treated wastes can then be removed by a conventional process 29 such as ion exchange after separation by the dewatering apparatus 31. Most of the waste materials, if metals are exceeding the above mentioned legal limits, can usually be removed below the legal requirements by this first step practice. In this way, only the first step is needed for the heavy metal removal.
(33) If after the first step the metal concentrations are still exceeding the legal requirements, the second step can be used. This step is practiced right before the dewatering operation in the HiSAP system, using nitric acid to reduce the pH lower than 1 (usually 1% concentrated nitric acid is sufficient for most treated wastes) in a mixing tank to further solubilize the heavy metals. Nitric acid is used because the resulting nitrate can be a fertilizer ingredient in the product produced. Again, the solubilized metals can be removed from the liquid stream by conventional metal removal methods such as ion exchange as shown above.
(34) When the second step is still cannot remove heavy metals down below legal limits, the third step is used. The third step involves an Acid/Chelating Extraction Device or an Electrokinetic Heavy Metal Removal device 29 (such as devices used for soil remediation practiced widely in the field) before pumping to the Equalization Tank 30. The solid/liquid mixtures stored in tank 30 can then be dewatered by applying a filter press 31 and adjusted the moisture contents of the solid portion to about 40 to 45% moisture contents and send to the Activation Reactor 32 for high-pressure steam activation processing, with or without additives.
(35) After that the material is through a Steam-Explosion Device 33 to further improve the quality of the solid fertilizer products. The liquid portion from the filter press 31 is pumped to the storage facility 34 in the Product Refining Plant, as shown in
(36) The Product Refining Plant shown in
(37) One process is to remove extra VOCs (volatile organics) and unwanted ions (such as extra salts or heavy metals) through a conventional salts/metals removal device 36. This treated liquid fluid from device 36 can then be processed in different ways for different liquid fertilizer types as shown in
(38) The treated liquid in 36 mentioned above also can be pumped to a Beneficial Bacteria Culturing Device 42, through bacteria culturing by selected bacteria addition and aeration operation to generate Bio-Liquid Fertilizer 43, which is used widely in the developing countries due to lack of microorganisms in their farmland by overuse of pesticides and herbicides. The treated liquid 36 above can also increase the humic and fulvic contents by Humic/Fulvic Reactor 44 (a mixing tank for adding commercially available humic substances or a ROS oxidation tank to increase the humic substances concentrations through the oxidation of lignocelluloses in the treated liquid from storage tank 34) and Concentration Device 45 and nutrients adjustment device 46 to produce Liquid Humic Fertilizer 47. Through tests, it is found that the low temperature conventional MVR devices can be used as the concentration devices 39 and 45.
(39) Moisture content is one of important parameters in the organic solid fertilizer products. The solid fertilizer base material in storage 35, can be moisture adjusted by a Moisture Adjuster 48 to adjust moisture contents of the base materials based on requirements by various fertilizer standards required by most regulatory agencies. The moisture adjuster can be a filter press for moisture reduction or a mixing tank for moisture addition depending on incoming and outgoing moisture requirements. The moisture contents of materials through the filter press 31 usually can be dewatered down to 25% when necessary.
(40) Further processing by moisture adjuster 48 includes pelleting by a conventional Pelletizer 49 to produce regular pelletized Solid Fertilizer 50 or grinding to powders by a commercially available grinder 51 to produce powdered Solid Fertilizer 52. The material through moisture adjustment by moisture adjuster 48 also can be further processed by Humic/Fulvic Reactor 53, to generate Humic Fertilizers 57 and 60. pelletized Solid Humic Fertilizer 57 is pre-treated by a nutrient adjuster 55, and a Pelletizer 56. powdered Solid Humic Fertilizer 60 is pre-treated by a nutrient adjuster 58, and a Grinder 59. The moisture adjusted product from moisture adjuster 48 also can be processed by mixing with beneficial bacteria Culturing Device 54 to produce Bio-Solid Fertilizer 61.
(41) Equipment needed for the Product Refining Plant as shown in
(42) 3. HiSAP Equipment and Instruments
(43) Major equipment and instruments used for the HiSAP system are shown in
(44) The incoming eco-wastes, biosolids, and/or other types of pretreated organic wastes are transported to and mixed in the physico-chemical pretreatment tank 23 through a conventional belt or a screw conveyer 801. Other types of material such as additives are inputted through openings 102, and dilution water 104 is inputted through and controlled by valve 103. The input materials are then mixed in the tank 23 by a mixer 101. Temperature of the material in tank 23 is raised by a heating coil 107 through waste heat recovery to a temperature as high as possible or until about 80 to 95 C. The processed materials are then outputted through a liquid-liquid heat-pipe exchanger 27 (as shown in
(45) The heated fluid is then pumped to the multi-conditioning reactor 24 through input opening 203. Additives, if needed, can be added through openings 202. The inputted materials are mixed by a mixer 201, and output. A heater 803 is provided to adjust the temperature when temperature cannot be reached to the desired levels (usually in the range of 140 to 170 C., depending on types of degradable materials to be treated).
(46) The output of the two-phased materials (slurry) through valve 205 are pumped through a second liquid-liquid heat-pipe exchanger 26, and then through a liquid-gas heat-pipe exchanger 28 to raise temperatures of the slurry for inputting into the first Curing Reactor 25 through a series of Nozzles 302 (as shown in
(47) The slurry in the Zone B of the curing reactor 25 is circulated downward and mixed with air and ROS (generated mainly in Zone A and by the Cylindrical Catalyst Device 304) to form a three-phase fluid and further forced to circulate downward in the Zone B until reach the bottom of the curing reactor 25, and the fluid then flows upward to Zone A (shown in
(48) The three-phase fluid contacts a plurality of Cathodes 307 to form various of ROS (principles are discussed in Section 6) and organic radicals. The fluid is then forced by a Mixing and Circulating Device 310 to flow through Openings 305 (shown in
(49) A series of multiple curing reactors 25 range from 1 to 4 are used (refer to
(50) A commercially available Filter Press 31 can be used to separate the treated fluid into two types of materials, one is a solid organic fertilizer stored in a Container 402 and another is a liquid organic fertilizer stored in Container 401. Through numerous product curing tests and plant growing tests, the inventor found that qualities of these two types of fertilizer product are very high, usually higher than conventional composts produced by biochemical methods based on various organic fertilizer quality tests.
(51) To further improve the quality of solid organic fertilizer products, the product stored in container 402 can be transfer to an Activation Reactor 32 by a Screw Conveyer 404 and then transfer to a Steam Explosion Device 33 through an Explosion Control Device 807 for further processing.
(52) The Activation Reactor 32 (shown in
(53) A series of specially designed Cup-Shaped Mixers 501 (refer to
(54) 4. Energy Recovery Equipment
(55) Specially designed Heat Pipe Exchangers 26, 27, and 28 are selected for energy recovery, as shown, respectively, in
(56) The Liquid-Gas Heat-Pipe Exchanger 28, as shown in
(57) 5. Principles and Equipment Design of the Multi-Conditioning Reactor
(58) As shown in
(59) In years of pilot tests, it has been found that soluble organics can be oxidized by ROS easily and rapidly if the contact opportunity between the soluble organics and ROS is provided. Mixing and Circulating Device 310 (refer to
(60) Non-soluble organic species existed as particulates will usually be partially oxidized only on the particle surfaces. The larger the particle sizes, the slower rates and less chances for the attack by ROS. However, particle sizes of Moderately Degradable Organics in the Reactor 25 cannot be too large due to the fact that: (1) large particles tends to trap Easily Degradable Organics in the particles, such as agricultural wastes which some protein, fat, and starch would be trapped in the lignocelluloses, which cause the degradation by ROS impossible; (2) large particles tend to reduce the functions of organic fertilizers during agricultural applications which trapped the celluloses in the hemicelluloses and/or lignin and therefore reduce the effectiveness of the organic fertilizers. The most ideal situation is to break the lignocelluloses fibers, expose and oxidize the hemicelluloses, and loosen the cellulose fibers to the extent that dissolution of celluloses will not occur. A carefully controlled shredding and grinding operation and selective solubilization by the Multi-Conditioning Reactor 24 can be utilized for the subject objectives. The most ideal particle sizes in the above situations are less than 2 mm sizes.
(61) The affecting factors of the above stated dissolution effects, besides the particle size (or surface area), other factors such as temperature, pH, agitation, redox potentials, solution composition, and solubility of the species itself will also affect the solubilization. Among them, temperature, particle size and agitation are controllable factors and can be incorporated into the reactor design. Mixers 201 (as shown in
(62) The above-mentioned temperature control is based on hydrolysis and/or dissolution temperatures required for Easily Degradable organics. Different Easily Degradable Organics in the wastes require different operation temperature to hydrolyze. Hydrolysis temperature and period required for hydrolysis are two most important variables of concern for design of the Multi-Conditioning Reactor 24 for the solubilization of Easily Degradable Organics.
(63) Among the Easily Degradable Organics, protein decomposition is most critical, because, these species associate with most secondary pollution sources such as odor, pathogens, and parasites. Hydrolysis of proteins will form mainly, amino acids, oligopeptides, carbohydrate side chains from glycoproteins, racemized proteins, etc. Our tests have found that most of the proteins can be hydrolyzed at temperatures above 120 C., majority of proteins can be hydrolyzed when temperature reaches 180 C., and almost all proteins are hydrolyzed at temperature reaching 230 C.
(64) As for fats in the incoming wastes, portion of complex fats will liquefy at room temperature, and at temperature beyond 80 C. most fats can be liquidized. When temperature greater than 180 C. majority of complex fats can be hydrolyzed into fatty acids and simple fats.
(65) As for the carbohydrates in the incoming wastes, hydrolysis in the Reactor 24 results in hydrolyzed glycogen (major glucose polymers from animal wastes), hydrolyzed starch (major glucose polymers from plant wastes), and simple sugars (such as glucose, galactose, mannose), etc. According to rough estimates, depends on types of wastes, approximately 55 to 65% of carbohydrates in food wastes can be hydrolyzed when temperature reaching 140 C., additional 25 to 35% of carbohydrates in wastes can be hydrolyzed reaching 140 C. to 230 C., and less than 10% remaining amount of carbohydrates need to be hydrolyzed at temperature beyond 230 C.
(66) Time needed for hydrolysis will depend on temperature, concentration, pH, particle sizes, etc. For most Eco-Wastes, period required from minutes to about 2 hours, when particle size is less than 5 mm and temperature within 140 to 230 C. However, the hydrolysis time can be reduced with the aid from acidic hydrolysis. To avoid over hydrolysis to reduce the production amount of solid organic fertilizer products, appropriate temperature range used is 140 to 180 C. In this temperature range hemicelluloses and a small portion of lignin of the lignocellulosic materials can also be hydrolyzed.
(67) Experiments found that cellulosic materials can be significantly hydrolyzed only when the temperature higher than 250 C. The hydrolysis of celluloses is undesirable due to the reason that quantity of solid organic fertilizer products will be reduced. Therefore, the hydrolysis temperature is controlled under 250 C. in this design.
(68) When temperature reaches 200 C., toxic organics, such as dioxin, benzene, PAH's, PCB's, pesticides, insecticides, herbicides, etc., in the organic wastes also can be effectively hydrolyzed.
(69) In general, the above-mentioned hydrolysis reactions can be completed from few minutes to about 2 hours. The more desirable hydrolysis conditions are selected at temperature from 140 to 180 C. and reaction period 2 minutes to 1 hour. The most desirable hydrolysis conditions for the design of the Multi-Conditioning Reactor 24 will be 150 to 170 C. and 10 to 30 minutes. Although the toxic organics as discussed above cannot be effectively solubilized, the ROS generated in the Curing Reactor 25 can add the decomposition of these compounds.
(70) Other objectives of the Multi-Conditioning Reactor 24, such as loosening of lignocelluloses, sterilization of pathogens, and destruction of weeds in wastes can also be accomplished in the Reactor by the application of elevated temperature as discussed previously. Hydrolysis of organics will cause reduction of pH levels of the slurry in the Multi-Conditioning Reactor 24. For the types of organic wastes mentioned above (such as MSW, restaurant wastes, animal wastes, biosolids, etc.) the pH levels of the slurry in the Multi-Conditioning Reactor 24 can be reduced to 4 to 5. This pH levels are favorable for the dissolution of heavy metals associated in the organic solid wastes. If concentration levels of heavy metals in the solid phases of the wastes are only moderately higher than the levels required by the regulation for use as fertilizers, dewatering of the wastes after the curing process (to be discussed in the following section) could reduce the heavy metal concentrations in the solid organic fertilizers produced due to the acidification effects of dissolution of metals in the Multi-Conditioning Reactor 24.
(71) The solubilized metals in the liquid phase can then be treated by conventional metal removal methods, such as ion exchange method. It is also reported in the open literature that the thermal chemical reactions in the reactors such as the conditions existed in the Multi-Conditioning Reactor 24 will also generate organic free radicals which can assist in breakdown the CC and/or CH bonds organics to further increase solubilization effects. Experiments have found that organics in the Multi-Conditioning Reactor shall be kept in reducing environments (i.e., negative redox potentials) to enhance the generating of organic radicals.
(72) 6. Principles and Equipment Design of the Curing Reactors
(73) Equipment profiles of the Curing Reactor 25 are shown in
O.sub.2+e.sup..fwdarw.O.sub.2..sup.(1)
(74) O.sub.2..sup. is reactive and can catch a H.sup.+ ion rapidly and form HOO. (Peroxyl radical or Hydrogen Peroxide Radical):
O.sub.2..sup.+H.sup.+.fwdarw.HOO.(2)
(75) Formation of HOO. also will avoid the generation of hydrogen gas from the system (which is different from the conventional electrolysis reaction of water to generate hydrogen gas). HOO. is unstable and will obtain another e.sup. and form HOO.sup.:
HOO.+e.sup..fwdarw.HOO.sup.(3)
(76) HOO.sup. will catch another H.sup.+ to form H.sub.2O.sub.2 (Hydrogen Peroxide):
HOO.sup.+H.sup.+.fwdarw.H.sub.2O.sub.2(4)
(77) In the HiSAP system, three types of major reactions may occur near the surface of the Cathode 307, as shown in
H.sub.2O.sub.2+e.sup..fwdarw.OH.sup.+OH.(5)
(78) The above OH.sup. formed will catch H.sup.+ and form Water H.sub.2O:
OH.sup.+H.sup.+.fwdarw.H.sub.2O(6)
(79) Combination of Equations (5) and (6) will form:
H.sub.2O.sub.2+e.sup.+H.sup.+.fwdarw.OH.+H.sub.2O(7)
(80) The overall reaction of the above (a) type from Equation (1) to (4) and (5) would give the above pathway's overall reaction happen in the bulk solution in Zone A: (Hereinafter referred to as A-Type reactions in Zone A:)
O.sub.2+3e.sup.+3H.sup.+.fwdarw.OH.+H.sub.2O(8)
(81) The above (b) type reaction will yield 2 OH.:
H.sub.2O.sub.2.fwdarw.2OH.(9)
(82) The overall reaction will result: (B-Type in Zone A:)
O.sub.2+2e.sup.+2H.sup.+.fwdarw.2OH.(10)
(83) The above (c) type reaction will form various types of oxidized species and breakdown of organic species, such as an example for oxidation of Fe.sup.2+:
H.sub.2O.sub.2+Fe.sup.2++H.sup.+.fwdarw.Fe.sup.3++OH.+H.sub.2O(11)
(84) The above Equation (11) is the well-known Fenton Reaction. Since e.sup. can be supplied from the cathodes continuously by the HiSAP design, Fe.sup.3+ in the bulk solution in Zone A formed above can be reduced again to carry on more Fenton Reactions, as shown below:
Fe.sup.3++e.sup..fwdarw.Fe.sup.2+(12)
(85) The overall reaction of the above (c) type will become: (C-Type in Zone A:)
O.sub.2+3e.sup.+3H.sup.+.fwdarw.OH.+H.sub.2O(13)
(86) From the above three types of reactions, the phenomena occur in Zone A of the Curing Reactor 25 initiated by injection of oxygen, supply of electron, and existence of hydrogen ion, is for the purpose of forming more of the hydroxyl radical in Zone A. Some of the intermediate species produced during various pathways of reactions shown above are extremely short life. Therefore, major species in the Zone A of the reactor, excluding the input materials, may include mixtures of O.sub.2, H.sub.2O.sub.2, OH., e.sup., Fe.sup.2+, Fe.sup.3+ (iron species may come from the catalyst provided, to be discussed later), H.sub.2O, and organics. These species may react rapidly in Zone A when they are in soluble forms. The Easily Degradable Organics are mostly hydrolyzed in the Multi-Conditioning Reactor 24 in soluble forms prior to the Curing Reactor 25, so will decompose through a series of chain reactions in Zone A. Any of the dissolved lignocelluloses in Zone A may start to oxidize also, although majority of the lignocelluloses, especially lignin and celluloses, are still in the insoluble particulate phases.
(87) Through the mixing action in Zone A, and the recirculation of the fluid up flow in Zone A from Zone B as shown in
(88) The fluid migrates from Zone A to Zone B in the Curing Reactor 25 will be oxidized further due to catalyst(s) provided on the Cylindrical Catalyst Device 304, which through Fenton Reaction will generate more OH. for oxidation of soluble organic species. Continuing generation of OH. is necessary since OH. reactions are extremely fast and unstable and so OH. only diffuses in a short distance. Mixing, recirculation, and Fenton reactions can continue supply of more OH. for oxidation of species in the Curing Reactor 25.
(89) In Zone B in the Curing Reactor 25, the influent slurry from the Multi-Conditioning Reactor 24 is distributed through a plural of Input Nozzles 302, as shown in
H.sub.2O.fwdarw.O.sub.2+2H.sup.++2e.sup.(14)
(90) Due to the formation of vortex, and high pressure (usually near 2.5 to 3.2 MPa of operating pressure provided by the subject design) in the Curing Reactor 25, oxygen generated by the Equation 14 reaction will be mainly in a dissolved form (DO). The H.sup.+ ion generated by Equation 14 and generated from the Multi-Conditioning Reactor 24 will be forced to flow from Zone B to Zone A for the consumption by various reactions (refer to Equations 8, 10, and 13) discussed above.
(91) Equation 13 shows that consumption of each O.sub.2 molecule require 3 e.sup.. Equation 14 indicates that generation of each O.sub.2 will contribute 4 e.sup.. Therefore, the DO generated in the Zone B (as shown in Equation 14), by theoretical evaluation, would provide of the oxygen needs in the Curing Reactor 25. As a result, supply of compressed air or oxygen from Input Opening 316 can be theoretically reduced 75%. In fact, the savings of compressed air would be larger than 75% due to the reason that only portion of O.sub.2 (usually 70 to 80% depending on the reactor design) in the compressed air phase can be effectively turn into DO. This situation explains why HiSAP can be much more effective and cost saving comparing to that of the systems of CN101508603B and CN104148357A.
(92) In Zone A near the surface of Cathodes 307, the regular water electrolysis may form H.sub.2 gas. However, at the presence of oxygen, based on the Equation 13 generation of OH. instead of H.sub.2 will occur. The free energy of Equation 13 can be calculated to be 67.28 Kcal, negative value implying that reaction of oxygen and hydrogen ion to form OH. are more thermodynamically favorable. On the surface of Cathodes 307 reduction of Fe.sup.3+ to Fe.sup.2+ (Equation 12) occurs which will carry on the Fenton Reactions (Equation 11) to continue generating OH. also. In fact, the type of Fenton Reactions will occur throughout the entire Curing Reactor 25, i.e., in bulk solutions in Zones A and B, surfaces of both Electrodes (generation on the surface of anodes will be further discussed later), and near the areas and on surfaces of the Cylindrical Catalyst Device 304. This special equipment design of the Curing Reactor 25 is very favorable and effective to generate ROS to enhance the oxidation of Easily Degradable Organics.
(93) ROS production in the Curing Reactor 25 is limited by the concentration of DO and availability of electron supply (or current density) in the system. Almost all currently available patented ROS reactor designs are for water or air purification and sterilization purposes. These water or air purification devices are operated at or near atmospheric pressure and at or near room temperatures. Therefore, the DO levels in these systems are relatively low (Note: saturation concentration of DO at room temperature under atmospheric pressure is only about 8 ppm). As for solid wastes treatment, so far no solid wastes partial wet oxidation or wet oxidation processes are using ROS approach. Since solid wastes contain much higher concentrations of organics in the treatment systems than that of water and air purification systems, carrying the ROS reactions in the room temperatures and under atmospheric pressure will result in shortage of DO in the system. To increase the concentration of DO, and enhance the oxidation reaction rates of ROS, the present invention develops and uses the thermal pressurized reactors. The high pressure provided by the Curing Reactor 25 can increase the DO levels. The screw shaped Cathodes 307 (refer to drawing in
(94) As discussed above, hydrogen ion is also needed for the generation of hydroxyl radical. Relative low pH levels resulted from the reactions in the Multi-Conditioning Reactor 24 and Curing Reactor 25 can increase the hydrogen ion concentrations and, therefore, increase the OH. formation rates and concentrations, as shown in Equations 13 and 14. The elevated temperature provided can further increase the oxidation rate of reaction.
(95) In the solid waste treatment, as discussed in the background section, due to high organic contents, oxidant demands are very high. Using premixed oxidant gases prepared at or only slightly higher than atmospheric pressures cannot reach to the dissolved oxidant levels needed. For treatment/recovery of solid wastes, use of pressurized reactors and operation at elevated temperatures and pressures are needed. Provision of fluid recirculation to increase the oxidation efficiencies are also necessary.
(96) In the present invention, the Curing Reactors 25 are operated in closed and oxidation environments with careful evaluation of waste characteristics and bench test results to obtain the ranges of elevated temperature and pressure to achieve the seven objectives of Curing Reactor 25 described in
(97) The temperature-pressure relationships VS requirements of detention time, supply and demand of oxidants for the destructions of Easily Degradable Organics in the reactor(s) of the present invention can be bench tested before full-scale design of the reactor. Based on that and the waste mass flow rates, the needs of oxidant supply and electric current density can be estimated. For most organic wastes tested so far by the present invention it is found that the most favorable temperature fall in the 180 to 210 C. range.
(98) For the selection of pressure, higher pressures favor higher saturated DO levels and thus faster and better organic destruction efficiencies. Higher pressure used can also reduce steam generated in the pressurized reactor and, therefore, reduce the heat requirement. However, the higher the operating pressures used, the higher the capital and operation costs will be needed. Therefore, optimum conditions and feasibility shall be evaluated to select the best pressure ranges. In our tests and evaluations, the minimum pressure required is at least 0.5 MPa beyond the saturated steam pressure of the above listed temperature ranges, and maximum pressures are governed by capital and operating costs. More favorable pressure ranges can be selected for the Curing Reactor 25 are 3 to 3.5 MPa. Under these conditions the saturated DO levels will be in the range of 250 to 350 ppm, comparing to about 8 ppm in the room temperature, atmospheric conditions. In the above temperature and pressure ranges the detention time needed for the Curing Reactor 25 is in the range of 10 minutes to 1 hour.
(99) The high-speed curing process is an exothermic reaction. For most Easily Decomposable Organics if the temperature selected is greater than 140 C. and easily decomposable organic contents are higher than 5%, and heat contents of the organics are greater than 3,000 Btu/pound, then no external heat energy supply is usually needed for the temperature maintenance of all the thermal reactors used in this HiSAP system. The steam generated through this process also enough for the supply to other operation processes which require steam such as High-speed Activation Process. In this way a great saving can be achieved by using the present invention for the organic fertilizer production.
(100) Destruction of Easily Degradable Organics and most toxic and odorous components of the organic wastes such as ammonia, sulfides, and mercaptans can be oxidized to nitrate, and sulfate salts to eliminate odors and converted to valuable fertilizer components by the Curing Reactors 25. Viruses and other pathogens, parasites, weeds can be eliminated under series of high temperature hydrolysis and oxidation reactions in this HiSAP system. Due to the formation of organic acids, pH ranges after the hydrolysis and oxidation reactions are usually in 4 to 5 range. Higher levels of Easily Degradable Organics in the wastes, and selection of longer detention time for operation will lower the pH levels in the reactors. Control of pH levels in the 3 to 6 range is possible by selection of proper detention time and additives. If heavy metal extraction, or removal of certain compounds are necessary from the products, pH can be adjusted lower. Low pH will affect the selection of reactor and pipeline construction materials. Stainless steel in this case becomes unfavorable, due to corrosion problem which will weak the facilities and release toxic heavy metals such as chromium into the products. In these cases, materials such as titanium or hastelloy shall be used as the reactor manufacturing material to avoid corrosion and metal contamination problems.
(101) Oxidation and destruction of Easily Degradable Organics, toxic organic compounds and minor portion of the hydrolyzed Moderately Degradable Organics in the Curing Reactors 25 can go through four pathways: (1) by hydrogen abstraction reactions, (2) by redox reactions, (3) by electrophilic addition to bond, and (4) by thermal cracking, as shown graphically in
(102) Hydrogen abstraction:
RH+OH..fwdarw.R.+H2O(15)
(103) Redox reaction:
RX+OH..fwdarw.RX..sup.++OH.sup.(16)
(104) Electrophilic addition:
RX+OH..fwdarw.RXOH.(17)
(105) Thermal cracking:
R.sub.1.fwdarw.R.sub.2.+R.sub.3.+(18)
(106) Radicals formed through above reactions can react instantly with oxygen to form peroxide derivative (ROO.):
R.+O2.fwdarw.ROO.(19)
(107) ROO. may react with water to form HOO. (hydroperoxyl radical) and ROH, or react with another organic to form organic radical R. and ROOH. These reactions imply the destruction of organics and generate organic-organic chain reactions for further breakdown of organics, as follows:
ROO.+H.sub.2O.fwdarw.ROH+HOO.(20)
ROO.+RH.fwdarw.ROOH+R.(21)
(108) The above HOO. and R. can initiate further chain reactions, or form more O.sub.2 and H.sub.2O.sub.2 again for further chain reactions, as shown bellows:
HOO.+ROO..fwdarw.RO.+O.sub.2+OH.(22)
HOO.+RH.fwdarw.R.+H.sub.2O.sub.2(23)
(109) In summary, as long as radicals are existing in the Curing Reactor 25 system, chain reactions will proceed to breakdown organics until no radicals are in the system. In case all secondary radicals are all consumed while more organics are pumped into the system for treatment, the supply of O.sub.2 and electron to the system will initiate above mentioned chain reactions again.
(110) Suitable materials for the construction of cathodes and anodes of the Curing Reactors 25 are: (1) regular and precious metals, such as Fe, Al, Ti, Ni, Cu, Ag, Pt, Au, etc.; (2) alloys of the above metals; (3) graphite, reticulated carbon (glassy carbon), carbon-PTFE; (4) metal oxides, or mixture of metal oxides containing at least one transition metal; and (5) composite materials, such as titanium-ceramic-Ebonex, metals doped with inorganic material. Among the above electrode materials, Titanium, graphite, reticulated carbon, Hastelloy are better cathode materials can be used for the Curing Reactor 25. For the anode electrode materials, the better choices will be Fe, Ti, metallic oxides, or any semiconductor materials. Fe electrode is relative inexpensive and may help to generate hydroxyl radicals, but itself will be sacrificed and requiring frequent replacement. Titanium anode if can be coated with titanium dioxide not only can assist forming hydroxyl radicals, the electron ejected from the electrode surface forming an electron hole also can assist attracting soluble organics to the hole to form organic radicals, and thus further breakdown organics.
(111) To further enhance the hydroxyl radical generation, Fenton reactions are created in the Curing Reactor 25 by a Cylindrical Catalyst Device 304. The cylindrical device has Fluid Recirculation Openings 305 and Catalyst and Fluid Guiding Plates 306 to recirculate and guide the fluid flow and increase the contact opportunities to enhance the reactions as shown in Equations 11 to 13 above. Suitable catalyst materials for the construction of the Cylindrical Catalyst Device 304 are Fe metal, Fe salts and Fe-complexes. In this Cylindrical Catalyst Device 304, Fe-salt catalysts can be selected from relatively insoluble iron compounds (either ferrous or ferric) of oxides, phosphates, polyphosphates, or pyrophosphates. For the Fe-complex catalysts, the following compounds can be selected: ligands containing polyphosphates or acetic derivatives of ethyleneamine, especially comprising EDTA and ethylenediamine. Thermally degraded lignocellulosic materials (can be formed in the Multi-Conditioning Reactor discussed above), or these materials, either in solid or liquid phases, forming complexes with iron and/or iron compounds can be good Fenton reaction catalysts also.
(112) 7. Principles and Equipment Design of the Wet Pulping and Separation Apparatus
(113) The wet processing method is developed for the subject recycling system. As discussed previously, all equipment used in the pretreatment system can be acquired commercially except the Apparatus 11 (Wet Pulping and Separation Apparatus). The Wet Pulping and Separation Apparatus 11 is developed by the present invention and can be used for the separation and removal of heavy fractions (usually including materials in the incoming wastes which the specific gravity is greater than 1.3), including metals, glasses, dirt, bones from the incoming waste streams. The remaining waste fractions (usually the specific gravity is less than 1.3), which are mainly plastics, food wastes and lignocelluloses, if any, are processed to two distinct groups of wastesone is a group of waste plastic material, and the other group is the major organic materials in the wastes including mainly food related wastes and lignocellulosic materials (also called Eco-Wastes mentioned previously). The above mention waste fractions can be effectively separated and recycled by using the Apparatus 11, as shown in
(114) The Wet Pulping and Separation Apparatus 11 is operated based on the specific particle size range, specific gravity differences of different types of material, principles of hydraulics, and pulping and non-pulping characteristics of incoming wastes. As shown in
(115) Metal Materials 12 (as shown in
(116) In the Compartment E, the Plastic Materials 17 (as shown in
(117) The principles, treatment systems and major apparatus are fully described above, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the appended claims.