METHOD AND APPARATUS FOR TREATING HUMAN REMAINS
A process for treating a human remains comprises the steps of subjecting the remains to pyrolysis in a pyrolysis chamber under conditions that convert the particulate material to biochar remains.
The invention relates to a method and apparatus for treating human remains. In particular, the invention relates to a method and apparatus for treating the human remains for burial or other means of disposal.
BACKGROUND ARTTraditionally, human remains are stored after death for a period of time prior to commitment. In most cases, the remains are initially embalmed, which involves draining the blood from the body and replacing it with an embalming fluid such as formalin, which serves to delay the decaying process. The remains are then generally either buried in a cask in the ground, or cremated.
There are a number of problems associated with these established practices. The problems associated with burial include ecological problems, namely that the toxins in the body eventually make their way into the ground and water table. These toxins include formalin, which is toxic and has recently been recognised as a carcinogen, mercury (which is present in dental fillings), and numerous other carcinogens. In addition, the body may also contain microbiological pathogens, including bacteria such as E. coli and S. aureus, viral pathogens and prions. A further problem associated with burial is that the conditions prevent mouldering of the body, with the result that the body rots under the influence of sulphur-producing bacteria, taking 80 years or more to fully decompose. Cremation is perceived as a cleaner, and more ecologically friendly, commitment process, and involves burning the remains at a high temperature of approximately 900° C. for a period of one to a few hours, depending on the size of the body. Any remaining skeletal bones may be crushed to provide the final ash, which is placed in an urn for final disposition. This is an energy intensive process, producing flue gases which are released into the atmosphere. These flue gases are known to include many toxins, including mercury.
Various attempts have been made to provide more ecologically, and environmentally, friendly methods of treating and disposing of human remains. For example, the literature includes details of numerous alternative processes, where the human remains are chilled, generally in liquid nitrogen, then fractured into particulate matter, and then freeze-dried to remove water, before finally being buried in shallow ground to allow aerobic decomposition take place. Examples of this prior art include the following documents:
U.S. Pat. No. 4,067,091 (Backman—1976)—describes a process of treating human remains which involves cryogenically cooling the remains in liquid nitrogen, size reducing the remains using mechanical means, freeze-drying the particulate matter to remove about 95% of water, and depositing the freeze-dried material in a storage container.
International (PCT) Application No: WO01/03516 (Max World Technology Inc—1999)—describes a process for treatment of biological waste similar to that of Backman (above) except that prior to cryogenically cooling the biological waste is subject to a dehydration step where at least 80% of water is removed. The process of the invention is intended for use with food, animal waste etc; use with human remains is not suggested.
European Patent Application No: EP1234151 (Promessa AB—2000)—describes a process for treating organic matter, including vegetable and animal waste, which employs cryogenically cooling and freeze-drying steps, and an additional intermediate step in which the chilled matter is subjected to a splitting process in which the chilled matter is perforated with high pressure water, steam or oil, or a high energy laser.
International (PCT) Patent Application No: WO2007/053078 (Wiigh-Masak et al—2006)—this application addresses the problems associated with, mouldering of remains following burial, and provides coffins having a specific C:N:P ratio suitable for promoting mouldering of the remains following burial. The process for treating the remains described in this Application includes cryogenically cooling, size reduction and freeze-drying.
International (PCT) Patent Application No: WO2008/147292 (Ecof-Fin GmbH—2008)—this process describes a method in which remains are put in a coffin that includes a mineral based filler and a polyolefin binder, cryogenically cooling the body and coffin, disintegration of the chilled matter using mechanical or ultrasound means, and freeze-drying the disintegrated matter. The problem that the invention addresses is the low pH of human remains that result from conventional alternative processes such as promession, which causes acidification of the soil; this process overcomes this problem.
International (PCT) Patent Application No: WO2008/116820 (DEmaco Holland BV—2008)—this process describes a method for treatment of human or animal remains including the steps of cryogenically cooling the body, size reduction of the chilled matter using mechanical or ultrasound means, and freeze-drying the size-reduced matter. The problem that the invention addresses is the inefficiency associated with freeze-drying human remains (time required, energy input), and the suggested solution is to dehydrate the remains (either prior to cooling or after size reduction) at a temperature higher than body temperature (generally less than 100° C.).
All of the above-referenced processes employ freeze-drying as a means of removing water from the remains. However, freeze-drying is recognised as being an energy intensive process, which is inefficient in terms of the process time and the amount of energy required to adequately remove water from the body. Moreover, it has been recognised that freeze-drying fails to kill all microbial pathogens, including virus and prions, which results in these microorganisms remaining in the dried tissue and generally being put back into the environment. Attempts have been made to address this issue by chemical (peroxide) treatment of the freeze-dried particulate matter, however while this has partially addressed the microbial contamination issue, it results in more toxic chemicals being employed in the process. Additionally, the methods of the prior art have failed to address the issue of formalin and mercury contamination.
It is also recognised that freeze-drying does not remove all water from the remains, and generally anything between 10% to 30% of the water in the remains will not be removed during freeze-drying. This also means that a substantial amount of embalming fluid is not removed from the remains, resulting in this embalming fluid being buried in the ground with the remains. The most common constituent of commercial embalming fluid, formalin, which is a solution of formaldehyde in water, is toxic and a known carcinogen. Thus, conventional burial of human remains, and also known alternative processes such as promession, lead to environmental contamination with a known carcinogen.
It is an object of the invention to overcome at least one of the above-referenced problems.
STATEMENTS OF INVENTIONBroadly, the invention provides a process for treating human remains comprising the steps of subjecting the remains to pyrolysis in a pyrolysis chamber under conditions that convert the remains to biochar remains.
Surprisingly, the process results in remains (biochar) that is free from mercury and other heavy metals, the toxic metals having been removed from the remains as a vapour to be subsequently condensed and stored away from the environment. Furthermore, the process of pyrolysis results in all microbial pathogens being destroyed.
In a preferred embodiment, the process comprises a further step of oxidation of the biochar subsequent to the pyrolysis step. This further step results in any volatile hydrocarbons in the biochar being oxidised, and also the removal of tar from the biochar by oxidation which facilitates subsequent handling of the biochar.
Suitably, the remains are dried prior to pyrolysis. Methods of drying the remains are described below, and include evaporative drying and freeze-drying. Other methods will be apparent to those skilled in the art. In the drying step, aqueous fractions, mainly water but also toxic aqueous fractions, for example formalin, are removed from the remains to reduce the water content of the remains. Typically, the remains are dried until the water content of the remains is 1-20%, preferably 5-10%, more preferably 7-9%, and ideally about 8% (w/w).
Typically, the remains are fragmented prior to pyrolysis. The fragmentation step may take place after drying, or preferably prior to drying. Methods of fragmenting the remains are described below, and other methods will be apparent to those skilled in the art.
Ideally, the remains are chilled prior to fragmentation by subjecting the remains, ideally the intact remains, to a cryogenic environment to reduce the temperature of the remains to a core temperature of −20° C. or below.
In a preferred embodiment, the process involves the steps of subjecting the remains to a cryogenic environment to reduce the temperature of the remains to a core temperature of −20° C. or below, subjecting the frozen remains to a fragmentation step to provide a frozen fragmented material, and drying of the frozen fragmented material ideally by evaporative drying, typically to a water content of 5-10% (w/w).
Compared with the prior art methods of treating human remains, the method of this preferred embodiment of the invention has a number of advantages. First, the method of the invention employs an initial evaporation step which removes a substantial amount of water from the corpse, followed by a pyrolysis step which converts the organic matter to biochar and, combustible gas by-products. This results in the energy needs of the process being reduced as the combustible gas by-products may be re-cycled to power the evaporation and/or pyrolysis steps. Further, the step of evaporation which is carried out prior to pyrolysis greatly reduces the amount of energy required to convert the particulate matter to biochar.
Thus, in a preferred embodiment of the invention, the process includes a step of removing gas by-products from the pyrolysis chamber. Examples of gas by-products generated during pyrolysis include methane. The gas by-products may be stored for recycling, or they may be directly recycled to power the evaporation and/or pyrolysis steps. In some embodiments, the gas by-products are fractionated to separate combustible gases from non-combustible gases.
The temperature and time of pyrolysis may be varied, but generally the temperature of operation will be at least 800° C., and generally higher. In one embodiment, pyrolysis is carried out at a temperature of 900° C., for a typical period from 30 minutes to four hours. Further, it will be appreciated that if a lower temperature is employed, the pyrolysis time may be increased, and vice-versa. It will also be appreciated that the pyrolysis conditions may be varied depending on the amount of particulate and the desirable features of the biochar to be produced (which of course depends on the size and composition of the remains).
Generally, the process of pyrolysis includes an initial step of hydrous pyrolysis and a subsequent step of anhydrous pyrolysis.
Generally, the drying step reduces the water content of the remains by 87-97%, preferably about 95%. This ensures that the remains include some water (generally about 5-10%, preferably 7-9%, and ideally about 8% (w/w) is desired) so that the initial pyrolysis step is anhydrous pyrolysis, ideally ablative flash pyrolysis. Preferably, drying is achieved by heating the remains, which is generally in the form of a frozen fragmented material, ideally by evaporative drying, to a temperature of generally above 100° C., typically about 150° C.- to 250° C., for a period of time suitable to reduce to water content of the remains to the desired level. Evaporated liquid is generally continually removed from the evaporation chamber, and is ideally condensed and either stored or further processed. In one embodiment, the liquid is distilled to remove toxic components such as, for example, formalin, which may be recycled to provide energy for the pyrolysis process. In another embodiment, the water removed from the particulate is subjected to a flash evaporation step.
In a preferred embodiment of the invention, the process of the invention includes a further step of separating mercury (optionally including other heavy metals) from the gaseous products of pyrolysis. This may be achieved by means of a water based cleaning process, where the mercury (and/or any other condensable toxic vapour) is removed by means of a water spray system, whereby the flue gas is sprayed with water and heavy mercury vapour (and any other condensable toxic vapour) will condense and be recovered. In another embodiment of the invention, mercury and other condensable toxic vapours may be removed from the combustion gases before they are allowed to exhaust to atmosphere. It will be appreciate that there are other methods of removing electrically conducting gas or vapour such as mercury from a mixture of other components.
Typically, the invention includes a further step of depositing the biochar remains in a container which may be sealed against ambient air.
The invention also provides a process for treating human remains to remove mercury or other heavy metals from the remains comprising the step of subjecting the remains to pyrolysis in a pyrolysis chamber under conditions that convert the particulate material to biochar remains, wherein flue gases expelled from the pyrolysis chamber are sprayed with an aqueous liquid, typically water, to condense the mercury or other metals for recovery.
Preferably, the method involves the steps of:
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- subjecting the remains to a cryogenic treatment to reduce the core temperature of the remains to a temperature of −20° C. or below; subjecting the frozen remains to a fragmentation step to provide a frozen fragmented material;
- removing water from the frozen fragmented material to reduce the water content of the frozen fragmented material, ideally to 5-10% water content (w/w);
- subjecting the partially de-watered fragmented material to pyrolysis in a pyrolysis chamber under conditions that convert the particulate material to biochar remains; and
- treating the gases generated as a result of the pyrolysis process to remove the mercury or other heavy metals from the gases.
Preferably, the gases are subjected to a water based spray cleaning step to condense the heavy metals from the gases. However, an electrostatic precipitation process may also be employed to remove the heavy metals or mercury from the gases. Ideally, the biochar remaining is free from mercury.
The invention also provides an apparatus for treating a human remains comprising a cryogenic chamber for subjecting the remains (generally intact remains) to cryogenic conditions, optionally means for providing a cryogenic fluid to the cryogenic chamber, a fragmentation apparatus adapted to receive the remains from the cryogenic chamber and capable of fragmenting the remains to a fragmented material, a drying chamber capable of removing liquid from matter contained therein (ideally by evaporative drying) and removing the liquid, and a pyrolysis chamber adapted for thermally decomposing the particulate matter in the absence of oxygen.
It will be appreciated that the apparatus of the invention may be employed to treat animal as well as human waste, and may also be employed to treat biological material such as, for example, medical and clinical waste and biohazardous waste.
It will be appreciated that the drying chamber and pyrolysis chamber may be provided as a single chamber, adapted to perform an initial de-watering step and a subsequent pyrolysis step.
In this embodiment, typically, the drying chamber is operably connected to a source of inert gas and includes means for charging the chamber with this inert gas. This enables a process of pyrolysis to occur, as charging the chamber with inert gas ensures that no oxygen remains within the chamber.
In one embodiment, the process of the invention includes a flash evaporation apparatus operably connected to the drying chamber and capable of performing flash evaporation on the evaporated water removed from the drying chamber.
Preferably, the drying chamber may be operably connected to a gas storage device and includes means for removing combustible gas by-products of the pyrolysis process during the pyrolysis process and storing the gas by-products in the gas storage device.
Generally, the drying chamber comprises a burner for heating the chamber, wherein the apparatus includes means for re-cycling gas from the gas storage device to the burner for heating the drying chamber. In some embodiments of the invention the gas storage device is omitted and the gaseous by-products of the pyrolysis are directly fed back to combustion for heating the pyrolysis chamber and/or the drying chamber.
Suitably, the apparatus includes a water spray adapted to remove heavy metal vapours, especially mercury, from the evolved gases.
In another aspect, the invention provides a process for treating human remains to remove embalming fluid from the remains comprising the step of treating the remains with heat to evaporate volatile components of the embalming fluid and optionally water vapour from the remains. The method of the invention results in remains which are substantially free of toxic volatile components such as formaldehyde, thus preventing these toxic components being returned to the environment.
Typically, the volatile components are recovered by condensation or dissolution in a solvent.
Suitably, the recovered volatile components are recycled to power the evaporation step, or another step in the process such as pyrolysis or fragmentation.
In one embodiment, the dehydrated remains are subjected to pyrolysis to convert the remains to a biochar.
Preferably, the recovered volatile components are recycled to power the evaporation step, the pyrolysis step, or both.
Typically, the recovered volatile components are stored prior to recycling.
In a preferred embodiment, the remains are fragmented prior to the evaporation step.
Suitably, the remains are subjected to a cryogenic environment to reduce the core temperature of the remains to a temperature below −20° C. prior to fragmentation.
Preferably, the evaporation step reduces the water content of the remains to 1-20% (w/w), more preferably to 6-10% (w/w), and ideally to about 8% (w/w).
Suitably, the volatile components, evaporated water vapour and other liquid by-products of the evaporation step are combined prior to separation by distillation.
Typically, the volatile components, evaporated water vapour and liquid by-products of the pyrolysis step are combined prior to separation by distillation.
Thus, in a preferred embodiment, the invention provides a process for treating human remains to remove embalming fluid from the remains comprising the steps of subjecting the remains to a cryogenic environment to reduce the core temperature of the remains to a temperature below −20° C., and subjecting the chilled remains to a size reduction step to provide a chilled particulate material. Volatile components of embalming fluid and water vapour (including aqueous fractions from the remains) are then evaporated from the chilled particulate material to reduce the water content of the chilled particulate material, generally until about 8% (w/w) is retained in the remains, and the partially de-watered particulate is then ideally subjected to pyrolysis to generate biochar and gaseous by-products of pyrolysis. The vapour fractions, including formaldehyde gas are preferably condensed and subsequently distilled to remove toxic materials from the environment, including formaldehyde.
The term “embalming fluid” as employed herein should be understood to mean the fluid that is employed by undertakers to preserve and fix a corpse prior to burial or commitment. These fluids exist under various trade names, and contain active ingredients usually including but not limited to alcohols, phenols and formalin, which is a solution of formaldehyde gas in water. Thus, process of the invention involves removal of formalin from the body as part of the aqueous fractions (which may be removed as formalin vapour, water vapour, and gaseous formaldehyde), and then subsequent distillation of the aqueous fractions to separate out and remove the formaldehyde for recycling.
The process of the invention, including the evaporation and pyrolysis steps, provides remains that are effectively free of water and embalming fluids. Thus, the problem of toxic or carcinogenic embalming fluids, or toxic or carcinogenic components thereof, being put back into the environment is obviated. The process of the invention also results in recovery of embalming fluids, or components thereof, in a purified form, and thus allows for re-cycling of the toxic components away from the environment.
Generally, the evaporation step reduces the water content of the remains to about 8% by weight. This ensures that the remains include some water (generally about 5-15%, 8-12%, and ideally about 8% is desired) to facilitate the pyrolysis process step. Evaporation is achieved by heating the remains to an elevated temperature (i.e. a temperature greater than body temperature) of generally above 100° C., typically from 150° C. to 250° C., for a period of time suitable to reduce to water content of the remains to approximately 8%. Evaporated aqueous fractions are generally continually removed from the evaporation chamber, and are then optionally condensed before further processing. In an embodiment in which distillation is performed on both the aqueous fractions and the liquid by-product stream of pyrolysis, the aqueous fractions and the liquid by-products may be combined prior to distillation. In another embodiment, the water removed from the particulate is subjected to a flash evaporation step.
In a preferred embodiment of the invention, the process includes a step of removing gas by-products from the pyrolysis chamber. Examples of gas by-products generated during pyrolysis include carbon containing gases such as CO2, CO, and methane. The gas by-products may be stored for recycling, or they may be directly recycled to power the evaporation and/or pyrolysis steps. In some embodiments, the gas by-products are fractionated to separate combustible gases from non-combustible gases, wherein the combustible gases may be recycled to power the evaporation and/or pyrolysis steps.
The temperature and time of pyrolysis may be varied, but generally the temperature of operation will be at least 250° C., 300° C., 350° C., 400° C., 450° C., 500° C., 550° C., 600° C., 650° C., 700° C., or 800° C. In one embodiment, pyrolysis is carried out at a temperature of from 300° C. to 1200° C., 400° C. to 1200° C., 500° C. to 1200° C., 600° C. to 1200° C., 700° C. to 1200° C., or 800° C. to 1200° C. Suitably, pyrolysis is carried out for a period of from 1 minute onwards, 1-24, 2-12, 3-10, 4-8 hours. Further, it will be appreciated that if a lower temperature is employed, the pyrolysis time may be increased, and vice-versa. It will also be appreciated that the pyrolysis conditions and duration may be varied depending on the amount of particulate (which of course depends on the mass and volume of the funereal remains).
In a preferred embodiment of the invention, the process of the invention includes a further step of separating mercury or other heavy metals from the biochar remains. This may be achieved by means of a condensation process, whereby the vaporised mercury is condensed by lowering its temperature to below 450° C. in temperature and the mercury (and any other vaporised metals present) will condense and be recovered. In one embodiment of the invention this may be achieved by using a water scrubbing process to lower the temperature of the flue gases. In another embodiment, a heat exchanger is employed to recover energy from the flue gases, thereby reducing the gas temperature to below 450° C. and condensing the mercury vapour from the flue gas stream.
Typically, the invention includes a further step of depositing the biochar remains in a container which may be sealed against ambient air.
The invention also provides an apparatus suitable for treating human remains comprising (a) a heating chamber adapted to receive human remains and heat the remains to evaporate water vapour and volatile components of embalming fluids from the remains, (b) optionally a pyrolysis chamber adapted to receive the dehydrated remains, subject the dehydrated remains to pyrolysis, and remove a liquid fraction by-product from the remains, (c) a distillation apparatus adapted to receive the evaporated water vapour and volatile components from the heating chamber and optionally the liquid fraction by-products from the pyrolysis chamber and distil the evaporated water vapour, volatile components and optionally the liquid fraction by-products to separate out and recover the volatile components, and (d) optionally a volatile component storage vessel adapted to receive and store the recovered volatile component.
The invention also provides an apparatus suitable for treating human remains comprising (a) a heating chamber adapted to receive human remains and heat the remains to evaporate water vapour and volatile components of embalming fluids from the remains, (b) a pyrolysis chamber adapted to receive the dehydrated remains, subject the dehydrated remains to pyrolysis, and remove a liquid fraction by-product from the remains, (c) a distillation apparatus adapted to receive the evaporated water vapour and volatile components from the heating chamber and the liquid fraction by-products from the pyrolysis chamber and distil the evaporated water vapour, volatile components and the liquid fraction by-products to separate out and recover the volatile components, and (d) optionally a volatile component storage vessel adapted to receive and store the recovered volatile component.
Preferably, the apparatus includes a condensation apparatus adapted to condense the evaporated water vapour and volatile components prior to distillation.
In one embodiment, the heating chamber and the pyrolysis chamber are provided as a single chamber adapted to perform evaporation and subsequently pyrolysis on the human remains.
Typically, the apparatus further includes a flash evaporation apparatus operably connected to the heating chamber and capable of performing flash evaporation on the evaporated aqueous fraction removed from the heating chamber.
Suitably, the pyrolysis chamber is operably connected to a source of an inert gas and includes means for charging the chamber with an inert gas.
Typically, the pyrolysis chamber is operably connected to a gas storage device and includes means for removing combustible gas by-products of pyrolysis and storing the gas by-products in the gas by-products storage device.
In a preferred embodiment, the pyrolysis combustion chamber comprises a burner, wherein the apparatus includes means for re-cycling the gas-by-products from the pyrolysis retort device to the combustion chamber burner for heating the pyrolysis chamber.
In another aspect, the invention provides an apparatus for treating human remains to remove embalming fluids, or toxic or carcinogenic components thereof, from the corpse, the apparatus comprising:
a cryogenic chamber adapted to receive human remains and subject them to cryogenic conditions;
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- a size reduction device adapted to receive the chilled remains from the cryogenic chamber and size reduce those remains to a chilled particulate material;
- a heating chamber adapted to receive the particulate from the size reduction device, evaporate volatile components and optionally water vapour from particulate material and remove the volatile components and water vapour;
- a pyrolysis chamber adapted to receive the at least partially de-watered particulate material from the heating chamber, subject the particulate matter to pyrolysis, and remove a gaseous by-product of pyrolysis;
- a distillation apparatus adapted to receive the evaporated volatile components and optionally water vapour from the heating chamber and subject them to distillation to separate out and recover some toxic materials; and
- a storage vessel for receiving formaldehyde gas from the distillation apparatus and appropriately storing the material for recycling.
- Suitably, the apparatus comprises a dispensing apparatus for placing the remaining bio char in an urn or pod for final disposition.
Preferably, the pyrolysis chamber is operably connected to a source of an inert gas and includes means for charging the chamber with an inert gas. This enables a process of pyrolysis to occur, as charging the chamber with inert gas ensures that no oxygen remains within the chamber.
Suitably, the pyrolysis chamber is operably connected to a gas storage device and includes means for removing combustible gas by-products of pyrolysis and storing the gas by-products in the gas by-products storage device. Typically, the pyrolysis chamber comprises a burner, wherein the apparatus includes means for re-cycling the gas-by-products from the pyrolysis chamber to the burner for heating of the pyrolysis chamber to the correct temperature, typically about 900° C.
In a preferred embodiment, the apparatus comprises a condensation process adapted to receive combustion gases from the heating chamber and remove heavy metals such as mercury from the gas by means of a heat exchanger or a water scrubbing process. It will be appreciated that other methods of removal of metal vapour such as electrostatic precipitation might be employed instead of, or as well as the water scrub or heat exchanger.
In this specification, the term “human remains” should be understood to mean a deceased human body, typically intact.
Although not the primary focus, it will be appreciated that the methods of the invention may be employed generally with biological matter, for example with animal remains, for example, agricultural animals such as cows, sheep, goats and poultry, domestic animals such as cats, dogs, and birds, and larger animals such as elephants and giraffes, where the remains are, typically, substantially intact, and clinical and medical waste, biohazardous waste and body parts.
In this specification, the term “cryogenic treatment” refers to bringing the remains into contact with a cryogenic fluid, such as nitrogen or helium, having a temperature of not greater than −100° C., ideally not greater than −150° C. The term “cryogenic fluid” should be understood to mean a fluid that exists in a liquid or gaseous form at least −100° C., preferably at least −150° C.
In this specification, the term “core temperature” should be understood to mean the temperature at the core of the remains. In humans, this would be, for example, the temperature in the centre of the torso. Generally this will be the highest temperature recorded within the remains during the cooling process.
In this specification, the term “fragmentation” should be understood to mean the process in which a mass is size-reduced into smaller particles. The term “fragmented material” should be understood to mean composed of particles that are produced as a result of size reduction or fragmentation. The particulate may be of any size, but generally has an average particle size of 10 mm or less (i.e. the particles have a diameter when measured at their widest of 10 mm or less). Ideally, the particulate has a particle size of less than 10 mm. Examples of fragmentation of frozen human remains are described in the documents referenced above, and include mechanical fragmentation, milling, grinding, exposure to ultrasonic sound waves, or exposure to pressure waves. When the human remains have been frozen to a core temperature of −20° C. or below, the remains will be very brittle and prone to shattering upon the application of force.
In this specification, the term “pyrolysis” is an art-recognised term and should be understood to mean the process of thermochemical decomposition of matter in the absence of oxygen. It is generally achieved by heating in the absence of oxygen to a temperature of at least 300° C., and often much higher, resulting in the long chain hydrocarbons being converted to short chain hydrocarbons, and a great increase in the elemental carbon content of the matter. In the process of the invention, the matter is converted into “biochar”, which should be understood to mean the matter that remains when biomass is subjected to pyrolysis. During the pyrolysis process, combustible gases are produced, and these gases may be removed from the pyrolysis chamber, and optionally combusted to power the pyrolysis process. Generally, these gases are lower alkane gases, such as methane or ethane. In one embodiment, the gas by-products removed from the pyrolysis chamber may be fractionated to separate the lower alkanes from other gases produced. In another embodiment, the gases removed may be stored. Methods and apparatus for performing pyrolysis are described in the literature, for example in WO2012012191 and US20110278149.
In this specification, the term “heavy metals” should be understood to mean mercury, cadmium, lead, chromium, arsenic, gold, silver and platinum.
In this specification, the term “flash evaporation” should be understood to mean an evaporation process when a saturated liquid stream undergoes a reduction in pressure by passing through a throttling valve or other throttling device.
In this specification, the term “inert gas” should be understood to mean a gas that does not undergo oxidation or hydrolysis reactions, for example nitrogen.
In this specification, the term “domestic animal” should be understood to means domestic pets, for example, dogs, cats, and rodents.
In this specification, the term “biological material” should be understood to mean waste material that contains biological subject matter such as blood, serum, cells, tissue, organs or limbs. Examples of such material include clinical and medical waste material, waste from hospitals, and other types of biohazardous waste.
In this specification, the term “aqueous components” should be understood to mean water, aqueous solutions such as embalming fluids (i.e. formalin and polyethylene glycol-based embalming solutions), and components of embalming fluids that are susceptible to evaporation (for example formaldehyde, alcohols, phenols etc.).
In this specification, the term “human remains” should be understood to mean a deceased human body, typically intact.
The term “fractional distillation” should be understood to mean the process of separating components (fractions) of a liquid mixture on the basis of their differing boiling points. Thus, a fluid containing a mixture of water and formalin can be separated into its components parts using fractional distillation, where the water will boil at or about 100° C. and the formaldehyde will boil off at or about 96° C., depending on its concentration in the formalin.
The term “particulate” should be understood to mean composed of particles that are produced as a result of size reduction. The particulate may be of any size, but generally has an average particle size of 10 mm or less (i.e. the particles have a diameter when measured at their widest of 10 mm or less. Ideally, the particulate has a particle size of less than 40 mm, 30 mm, 20 mm, 15 mm or 10 mm.
In this specification, the term “electrolysis” should be understood to mean the decomposition of water into hydrogen and oxygen due to an electric current being passed through the water. Generally, an electrical power source is connected to two electrodes made from an inert metal such as platinum, which are placed in the water. Hydrogen will appear at the negative electrode and oxygen at the positive electrode. In one embodiment, an electrolyte such as salt is added to the water prior to electrolysis to increase the electrical conductivity of the water. Such equipment is commercially available and can provide the required quantities of hydrogen and oxygen gas.
The process of the invention is intended primarily for treatment of human remains, but it may also be employed for treatment of animal remains, such as domestic pets, and biological material such as hazardous biological waste from a clinical or medical environment. In this specification, the term “domestic animal” should be understood to means domestic pets, for example, dogs, cats, and rodents.
The term “animal remains” should be understood to mean agricultural animals such as cows, sheep, goats and poultry, and larger animals such as elephants and giraffes, where the remains are, typically, substantially intact.
In this specification, the term “biological material” should be understood to mean waste material that contains biological subject matter such as blood, serum, cells, tissue, organs or limbs. Examples of such material include clinical and medical waste material, waste from hospitals, and other types of biohazardous waste.
The invention will be more clearly understood by the following description of some embodiments thereof, given by way of example only, with reference to the accompanying figures in which:
Referring to the drawings, and initially to
In the Freezing (cooling) stage 20, the remains are placed in a cooling bath in a cooling vessel, and liquid nitrogen at a temperature of −196° C. is poured into the bath until the remains are completely immersed in liquid nitrogen. The remains are left immersed in the liquid nitrogen for a period of 1 hour, which is sufficient to reduce their core temperature to −100° C. or less. The chilled remains are then removed from the bath and cooling vessel for further processing. It will be appreciated that other methods of cooling the remains will be available, for example immersing them in liquid helium or liquid hydrogen or other cryogenic liquids or gases.
In the fragmentation (size reduction) stage 30, the chilled remains are subjected to a size reduction process where the remains are converted to a particulate matter having a particle size of about 10 mm. In the present embodiment, the chilled remains are subjected to a milling process which converts the remains to a particulate matter, which is then passed through one or more screens to ensure that the particulate matter has the desired average particle diameter of about 10 mm. The screening also removes large metal objects from the particulate, for example metal prostheses such as replacement hips or joints. The particulate matter may also be subjected to a magnetic screen to remove ferrous metal objects from the coarse particulate, prior to further processing. It will be appreciated that other methods of size reducing the remains are possible, for example subjecting the remains to ultrasound frequency or high pressure shock waves generated by the initiation of combustible gases.
In the drying (de-watering) stage 40, the particulate matter generated during the size-reduction stage is subjected to a heat treatment to remove aqueous fractions, including water and water soluble toxins such as embalming fluids and components of embalming fluids. The particulate matter is placed in a heater chamber, and heated at a temperature of up to 250° C. for a period of 30 minutes, whereupon most of the water (about 96%) in the particulate is removed by evaporation at atmospheric pressure. Aqueous fractions removed from the particulate are condensed 41 and collected 42. This evaporation step has been found to be particularly beneficial insofar as it reduces the energy input required to convert the particulate matter to biochar during the subsequent pyrolysis step. Ideally, the remains have about 8% water (w/w) at the end of the drying stage.
In the pyrolysis stage 50, the at least partially de-watered particulate is placed in a pyrolysis chamber and heated in the absence of oxygen to a temperature of 900° C. for a period of 1 hour. During this process, the particulate matter is thermally decomposed to biochar having an initially high elemental carbon content. The pyrolysis process denatures/destroys all bacteria, virus, and prions. Further, the resultant biochar is provided in a form free of mercury.
In a final storage stage 60, the biochar is placed in an urn capable of being sealed to the environment, before being provided to the relatives for final disposition.
Referring now to
Referring now to
Referring to
A conveyor 136 conveys the particulate matter to a drying chamber 140, where the particulate is heated to evaporate water from the particulate. The heating chamber 140 includes a water vapour removal line 141 from which water vapour in the chamber is removed and conveyed to a condenser 142 and water storage chamber 143. A conveyor 144 conveys the de-watered particulate to a pyrolysis chamber 150. The pyrolysis chamber 150 includes an inert gas supply line 151 for charging the chamber with an inert gas prior to the start of the pyrolysis process, and optionally a gas removal line 152 for removing gaseous pyrolysis by-products from the pyrolysis chamber during the pyrolysis process to a gaseous by-product storage chamber 153. A further gas line 154 is provided for supply of gas by-products to the pyrolysis chamber for combustion.
The apparatus 100 optionally also includes a water spray 160 adapted to clean gases evolved in the pyrolysis chamber 150 via a heat exchanger and flue system 161 and remove heavy metals, especially mercury, from the gases through condensation.
Various ways of performing the method of the invention are envisaged, including the methods shown in Tables 1 to 5 below:
It will be appreciated that the methods described above may be embodied in a variety of different apparatus without altering the method used.
Referring to
In the cooling stage 220, the remains are placed in a cooling bath in a cooling chamber, and liquid nitrogen at a temperature of −196° C. is poured into the bath until the remains are completely immersed in liquid nitrogen. The remains are left immersed in the liquid nitrogen for a period of 1 hour, which is sufficient to reduce their core temperature to −20° C. or less. The chilled remains are then removed from the bath and cooling chamber for further processing. It will be appreciated that other methods of cooling the remains will be available, for example immersing them in liquid helium or liquid hydrogen or another cryogenic liquids or gases.
In the size reduction stage 230, the frozen remains are subjected to a size reduction process where they are converted to a particulate matter by means of a pressure wave generated through initiation of an oxygen and hydrogen gas mixture. The frozen particulate matter is then optionally screened to ensure that the particulate matter has the desired average particle size. The screening also removes large metal objects from the particulate, for example metal prostheses such as replacement hips or joints. The particulate matter may also be subjected to a magnetic screening process to remove small ferrous metal objects from the coarse particulate, prior to further processing. It will be appreciated that other methods of size reducing the corpse are possible, for example subjecting in the corpse to ultrasound frequency or high pressure shock waves or other mechanical means.
In the de-watering stage 240, the particulate matter generated during the size-reduction stage is subjected to a heat treatment to remove aqueous fractions, including water and water soluble toxins such as embalming fluids and components of embalming fluids. The particulate matter is placed in a heater chamber, and heated at a temperature of up to 250° C. for a period of 30 minutes, whereupon most of the water (about 96%) in the particulate is removed by evaporation at atmospheric pressure. Aqueous fractions removed from the particulate are condensed 241 and collected 242. This evaporation step has been found to be particularly beneficial insofar as it reduces the energy input required to convert the particulate matter to biochar during the subsequent pyrolysis step.
In the pyrolysis stage 250, the at least partially de-watered particulate is placed in a pyrolysis chamber and heated in the absence of oxygen to a temperature of 900° C. for a period of from 1 minute to 1 hour. During this process, the particulate matter is thermally decomposed to biochar having an initially high elemental carbon content. The pyrolysis process denatures/destroys all bacteria, virus and prions. Further, the resultant biochar is provided in a form free of mercury.
In the distillation stage 260, the aqueous fraction from the de-watering stage 240 is subjected to fractional distillation to separate out embalming fluids (i.e. formalin) or components of the embalming fluids (i.e. formaldehyde) from the water. The separated embalming fluids or components are stored 261 or recycled in the process via combustion to heat the pyrolysis chamber.
Referring now to
Referring to
A conveyor 236 conveys the particulate matter to a heating chamber 240, where the particulate is heated to evaporate aqueous fractions from the particulate. The heating chamber 240 includes a vapour removal line 241 from which the aqueous fractions in the chamber are removed as vapour and conveyed to a condenser 242 where the vapour is condensed. The condensed vapours are then transferred to a fractional distillation apparatus 260 where the aqueous fractions are subjected to fractional distillation to separate out and recover the formaldehyde or formalin and other toxic materials. A conveyor 244 conveys the de-watered particulate to a pyrolysis chamber 250. The pyrolysis chamber 250 includes an inert gas supply line 251 for charging the chamber with an inert gas prior to the start of the pyrolysis process, and optionally a gas removal line 252 for removing gaseous pyrolysis by-products from the pyrolysis chamber during the pyrolysis process to a gaseous by-product storage chamber 253. A further gas line 254 is provided for supply of gaseous by-products to the pyrolysis chamber for combustion.
In a further example, human remains are placed in a heating chamber, and subjected to heating at a temperature of 150° C. for a period of time until the water content of the remains is determined to be approximately 8% (w/w). During the heating period, water vapour (including aqueous fractions from the remains) and formaldehyde (from the embalming fluid) are evaporated from the remains and withdrawn from the heating chamber to a condensation unit where they are condensed or dissolved, prior to being distilled in a distillation apparatus to separate out and recover substantially pure formaldehyde. The formaldehyde is stored prior to re-use to power the evaporation unit, or other steps in the process. It will be appreciated that the stored formaldehyde may also be stored and packaged for re-use in industry.
The invention is not limited to the embodiments hereinbefore described which may be varied in construction and detail without departing from the invention.
Claims
1. A process for treating human remains comprising the steps of subjecting the remains to a pyrolysis in a pyrolysis chamber under conditions that convert the remains to biochar remains.
2. The process of claim 1 comprising a further step of oxidation of the biochar subsequent to the pyrolysis step.
3. The process of claim 1 in which the remains are dried prior to pyrolysis.
4. The process of claim 3 in which the remains are dried to have a water content of about 6-12% (w/w).
5. The process of claim 3 in which the remains are dried to have a water content of about 8% (w/w).
6. The process of claim 1 in which the remains are fragmented prior to pyrolysis.
7. The process as claimed in of claim 6 in which the remains are chilled prior to fragmentation by subjecting the remains, ideally the intact remains, to a cryogenic environment to reduce the temperature of the remains to a core temperature of −20° C. or below.
8. The process of claim 1 comprising the steps of:
- subjecting the remains to a cryogenic treatment to reduce the core temperature of the remains to a temperature of −20° C. or below;
- subjecting the frozen remains to a fragmentation step to provide a chilled fragmented material;
- drying the chilled fragmented material from the particulate to reduce the water content and
- subjecting the partially dried fragmented material to pyrolysis in a pyrolysis chamber under conditions that convert the particulate material to biochar remains, whilst releasing the latent chemical energy within the remains.
9. The process of claim 8 in which the step of pyrolysis generates combustible gases which are removed from the pyrolysis chamber and re-cycled to power the pyrolysis and/or evaporation steps.
10. The process of claim 1 including a further step of removing mercury from flue gases produced in the pyrolysis step, optionally by means of a gaseous cleaning process.
11. The process of claim 3 in which the drying step reduces the water content of the remains to 1-20% (w/w).
12. The process of claim 3 in which the drying step reduces the water content of the remains to 5-10% (w/w).
13. The process of claim 1 in which pyrolysis is carried out at a temperature of at least 800° C.
14. The process of claim 1 in which the pyrolysis step comprises an anhydrous pyrolysis step, or a hydrous pyrolysis step, or both anhydrous and hydrous pyrolysis steps.
15. The process of claim 14 in which the pyrolysis step is carried out in two stages, a first hydrous stage where the partially de-watered particulate matter is heated in the absence of oxygen and presence of water to generate a fully de-watered particulate matter, and a second anhydrous stage where the fully de-watered particulate matter is heated in the absence of oxygen and water.
16. The process of claim 1 including a further step of depositing the biochar remains in a container which may be sealed against ambient air.
17. The process of claim 1, wherein flue gases expelled from the pyrolysis chamber are sprayed with an aqueous liquid, typically water, to condense the mercury or other metals for recovery.
18-56. (canceled)
Type: Application
Filed: May 7, 2013
Publication Date: Apr 2, 2015
Inventors: Damian Tinsley (Northern Ireland), Joe Ennis (Dublin)
Application Number: 14/398,938
International Classification: C10B 53/00 (20060101); F23G 1/00 (20060101);
