Patent Application
20170275542
The present application relates generally to waste and waste stream processing, and more particularly to converting varied source industry wastes into energy.
Presently, manufacturing processes produce wastes that are harmful to the environment. These wastes manifest in the form of solids, liquids, and gases that many times find their way deep into the ground to pollute underground water resources. The wastes also find their way into water streams that eventually meet rivers thereby polluting the rivers. If/when these wastes are sent to a landfill, they tend to disintegrate into most potent greenhouse gases such as methane.
Sometimes the wastes have been incinerated in an attempt to reduce the amount of waste generated by manufacturing processes. Incineration of the wastes has been used to recover energy from the wastes. However, incineration processes has various drawbacks. For example, incineration of these wastes causes emissions of more toxic gases such as dioxins and furans into the air. Furthermore, incineration completely rules out production of gaseous fuel from the wastes as an energy source because during incineration none of the hydrocarbons of the wastes survive in a combustible form.
Energy recovery by means of gasification has also been used. However, because industry and manufacture processing generates wastes from varied sources, many of which are not similar in terms of physical and chemical properties, it has posed a considerable challenge to well established methods of gasification such as fluidized bed gasification, moving bed gasification, and entrained bed gasification. In order to work efficiently, each of these methods require strict adherence to physical and chemical properties for the waste being processed. This is a problem because industry and manufacturing processes often to produce wastes at different stages of manufacturing that are not uniform with respect to physical and chemical properties.
The present disclosure generally provides an improved gasification apparatus, system, and method for processing varied source wastes containing hydrocarbons. This results in a single apparatus, system, or method to process hydrocarbon-containing materials produced from various stages of manufacturing processes, thereby increasing environmental stewardship.
The system and method include the use of a gasification apparatus comprising a rotary kiln reactor and a gas distributor. The rotary kiln reactor and gas distributor are configured to generate multiple reaction environments within the gasification apparatus. Each of the reaction environments has unique temperature and pressure conditions that process various components of the hydrocarbon-containing wastes.
Gasification is a process by which hydrocarbon-containing materials/wastes are converted into a combustible mixture of gases including carbon monoxide, hydrogen, methane, water vapor, and carbon dioxide. This combustible mixture of gases has the potential of providing a direct source of energy to industry and to manufacturing processing, or it can be used as fuel for generating steam and or electricity for manufacture processing. According to the present disclosure, the conversion of the combustible mixture of gases into energy uses an improved gasification method, as described herein, which is amenable to complete utilization of all hydrocarbon-containing wastes generated by manufacturing and industry processes. This results in less environmental pollution and considerable savings for the manufacturing industry.
Additional features of the present disclosure will become apparent to those skilled in the art upon consideration of the following detailed description exemplifying the best mode for carrying out the disclosure.
Embodiments of devices, systems, and methods are illustrated in the figures of the accompanying drawings which are meant to be exemplary and not limiting, in which like references are intended to refer to like or corresponding parts, and in which:
The detailed description of aspects of the present disclosure set forth herein makes reference to the accompanying figures, which show various embodiments by way of illustration. While these various embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that logical and mechanical changes may be made without departing from the spirit and scope of the disclosure. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not limited to the order presented. Moreover, references to a singular embodiment may include plural embodiments, and references to more than one component may include a singular embodiment.
The present disclosure generally relates to an improved gasification apparatus, system, and method for processing hydrocarbon-containing wastes. The system and method include the use of a gasification apparatus comprising a rotary kiln reactor and a gas distributor. The rotary kiln reactor and gas distributor are configured to generate multiple reaction environments within the gasification apparatus. Each of the reaction environments has unique temperature and pressure conditions that process various components of the hydrocarbon-containing wastes. This is beneficial because it enables processing of varied-source hydrocarbon-containing wastes with widely varying physical and chemical properties.
Referring to
The gas distributor 108 (an expanded view being provided in
The gas distributor 108 may be a tubular structure having a circular or nearly circular cross-section (as depicted in
A movable overlay 210 is fitted to the tubular portion 206 of the gas distributor 108. As illustrated, the movable overlay 208 is a half-spherical structure that covers about 180 degrees of the circumference of the tubular portion 206. As such, the overlay 208 may be capable of covering all or substantially all of the gas outlet ports 204 while in a single orientation. However, one skilled in the art should appreciate the overlay 208 covering more or less than 180 degrees of the tubular portion 206, less than substantially all of the gas outlet ports 204, and having any shape that allows it to mate with the tubular portion 206 without departing from the scope of the present disclosure. The movable overlay 208 is configured to rotate about the tubular portion 206 to direct the flow of gas through the gas outlet ports 204 within desired ranges. For example, the movable overlay 208 may be moved to cover less gas outlet ports 204 when less pressure is desired and more gas outlet ports 204 when more pressure is desired. The composition of the gas distributor 108 and overlay pipe 208 may be selected to withstand temperature of up to about 2200° F.
The hydrocarbon-containing wastes may be conveyed into the rotary kiln reactor 102 using a solid conveyer 104 such as a screw feeder, for example. The screw feeder 104 uses a rotating screw blade to move the hydrocarbon-containing wastes into the rotary kiln reactor 102.
Water may be introduced into the rotary kiln reactor 102 via a water inlet 110. The water may be introduced at rate of about 25% to about 30% by weight of that of the varied-source hydrocarbon-containing waste on dry basis. Moreover, the hydrocarbon-containing wastes may be in gas, solid and/or liquid states. The gases introduced into the gas distributor 108 may be oxygen and/or non-oxygen bearing. The gases may be delivered into the rotary kiln reactor 102 in varying quantities and compositions along the length of the rotary kiln reactor 102 in a manner that allows the gases to contact the hydrocarbon-containing wastes along a wall of the rotary kiln reactor 102.
Distribution of the gases along the length of the rotary kiln reactor 102 may be achieved by varying the lengths of the gas inlets 106 within the rotary kiln reactor 102. In an example, as depicted in
Contact of the solid and liquid hydrocarbon-containing wastes with the gases may result in physical interaction and chemical reactions that reshape the chemical composition of the gaseous fuel generated from the said wastes. Moreover, contacts of the solid and liquid hydrocarbon-containing wastes with the gases may also result in thermochemical transformation that transforms the solids into a gaseous state. These interactions and transformations produce gaseous fuels. The apparatus 100 of the present disclosure, while being configured to perform the above identified interactions and transformations, may also be configured to dry and devolatilize hydrocarbon-containing wastes, to remove and destroy agents of organic contamination in inorganic materials including soils, as well as to produce bio-chars from biomasses without necessitating physical alternation of the apparatus 100. The apparatus 100 may be configured to perform only a portion of the above identified operations at a time, in which case switching between configurations to perform the different operations may be automatic and instantaneous.
The apparatus 100 operates independent of the type of hydrocarbon-containing wastes, thereby enabling hydrocarbon-containing wastes with varying compositions and physical properties to be processed by the apparatus 100 without needing to alter the apparatus 100 in any material way. The apparatus 100 also operates independent of the size of the hydrocarbon-containing wastes introduced therein, thereby allowing hydrocarbon-containing wastes of varying sizes to be processed by the apparatus 100 without needing to alter the apparatus 100 in any material way. For example, the apparatus 100 may process hydrocarbon-containing wastes ranging from about 0.1 inches to about 6 inches, and preferably from about 0.1 inches to about 2 inches. In an example, the apparatus 100 may be configured to permit passage of gas through the apparatus 100 that is about 40 times greater in weight than that of the hydrocarbon-containing wastes introduced into and processed by the rotary kiln reactor 102. In another example, the apparatus 100 may be configured to permit passage of gas through apparatus 100 that is about 20 times greater in weight than that of the hydrocarbon-containing wastes introduced into and processed by the rotary kiln reactor 102. The apparatus 100 may perform processing operations at a range of temperatures including about 100° F. to about 3000° F., and preferably from about 100° F. to about 2200° F. The apparatus 100 may also perform processing operations at a range of pressures, including pressure within the apparatus 100 being about minus 1 inch of water column to about 100 inches of water column.
Referring to
As mentioned herein, wet hydrocarbon-containing wastes may be dried within the apparatus 100, namely within the rotary kiln reactor 102. While the wet hydrocarbon-containing wastes are in the rotary kiln reactor 102, hot gases are entered into the rotary kiln reactor 102 via the gas outlet ports 204. The hot gases may have a temperature of about 300° F. to about 1000° F. Prior to introduction into the rotary kiln reactor 102, the wet hydrocarbon-containing wastes may be at room temperature. Preferable drying of wet hydrocarbon-containing wastes is attained when the hot gases are uniformly distributed within the four zones of the gas distributor 108. During contact between the wet hydrocarbon-containing wastes with the hot gases, heat is transferred from the gases to the hydrocarbon-containing wastes (e.g., solids), causing the hydrocarbon-containing wastes to heat up to a range of about 150° F. to about 250° F., at which time moisture in the hydrocarbon-containing wastes (e.g., solids) evaporates and converts into steam. The steam is discharged from the rotary kiln reactor 102 with the other hot gases and directed to a cyclone 400 (described in detail below).
The general reactions or schematic reactions involved during drying of the wet hydrocarbon-containing wastes are as follows:
Hydrocarbon-Containing Material+Water+Hot Gas→Hydrocarbon-Containing Material+Steam+Cooled Gas
The dried hydrocarbon-containing wastes are discharged from the rotary kiln reactor 102 as ash via the means 112 for removing solids from the rotary kiln reactor 102.
The apparatus 100 may perform pyrolysis of the hydrocarbon-containing wastes by heating hydrocarbon solids to a temperature in the range of about 800° F. to about 1000° F., at which time volatile matter present in the hydrocarbon-containing wastes is vaporized. The volatile matter comprises mainly large molecule hydrocarbons, small molecule hydrocarbons, combustible gases including carbon monoxide and hydrogen, and non-combustible gases including carbon dioxide, nitrogen and water. In utilizing the apparatus 100 for the pyrolysis of the hydrocarbon-containing wastes, the hydrocarbon-containing wastes are introduced into the rotary kiln reactor 102 where they are contacted with hot gases introduced into the rotary kiln reactor 102 through the gas distributor 108.
The general reactions or schematic reactions involved during pyrolysis of the hydrocarbon-containing wastes are as follows:
Hydrocarbon-Containing Wastes+Hot Gases→Hydrocarbons+CO+H2+CO2+H2O
Hydrocarbons→Liquid Hydrocarbons+Gaseous Hydrocarbons
Vaporization of the hydrocarbon-containing wastes may also occur using the following methodology. The hydrocarbon-containing wastes are partially combusted to generate adequate heat to raise the temperature of the hydrocarbon-containing wastes to about 800° F. to about 1000° F. Prior to introduction of hydrocarbon-containing wastes, the rotary kiln reactor 102 is heated to a temperature above an ignition temperature of the hydrocarbon-containing wastes. Oxygen-bearing gases used to ignite the hydrocarbon-containing wastes are introduced into the rotary kiln reactor 102 through the gas distributor 108. Room temperature hydrocarbon-containing wastes are introduced into the preheated rotary kiln reactor 102. Introduction of the room temperature hydrocarbon-containing wastes into the rotary kiln reactor 102 may occur prior, during, or after the oxygen-bearing gases are introduced into the rotary kiln reactor 102. Beneficial results for the pyrolysis of the hydrocarbon-containing wastes using this method are attained when the oxygen-bearing gases are uniformly distributed throughout the four zones of the gas distributor 108. During the contact of solid hydrocarbon-containing wastes with the oxygen-bearing gases in the rotary kiln reactor 102, the hydrocarbon-containing wastes are partially combusted. The heat of combustion causes the temperature of the hydrocarbon-containing wastes to rise to about 800° F. to about 1000° F., at which time volatiles contained in the hydrocarbon-containing wastes evaporate into a gaseous phase. The general reactions or schematic reactions involved in this pyrolysis methodology include the following:
Hydrocarbon-Containing Wastes+Air→Hydrocarbons+CO+H2+CO2+H2O+N2 Hydrocarbons→Liquid Hydrocarbons+Gaseous Hydrocarbons
According to the aforementioned methodology, the solid residue discharged from the rotary kiln reactor 102 contains inorganic components of the hydrocarbon-containing wastes as well as fixed carbon present in the hydrocarbon-containing wastes. This solid residue has clean burning properties and is therefore considered high-grade solid fuel. When the hydrocarbon-containing wastes employed during this pyrolysis methodology is biomass, the solid residue discharged from the rotary kiln reactor 102 constitutes bio-char.
When the intended use of the apparatus 100 is to carry out gasification of the hydrocarbon-containing wastes to produce clean gaseous fuel for utility use, the hydrocarbon-containing wastes are reacted with oxygen bearing gases (i.e., air) and water (i.e., vapor) at an elevated temperature to convert hydrocarbon-containing material into a mixture of combustible and non-combustible gases. The fuel gas mixture may include carbon monoxide, hydrogen, methane, ethane, carbon dioxide, water vapour, and nitrogen. Additionally, the fuel gas mixture may have a caloric value in the range of about 80 to about 320 BTU per cubic foot irrespective of a composition of the varied-source hydrocarbon-containing waste processed/gasified. In this instance, room temperature hydrocarbon-containing wastes are introduced into the kiln reactor 102, which is preheated to a temperature above an ignition temperature of the hydrocarbon-containing wastes. Oxygen-bearing gases are used to ignite the hydrocarbon-containing wastes and are introduced into the rotary kiln reactor 102 through the gas distributor 108. For gasification to occur beneficially, the hydrocarbon-containing wastes may have about 20% to about 50% water content. If the hydrocarbon-containing wastes do not contain a sufficient water content prior to introduction into the rotary kiln reactor 102, water is introduced to the hydrocarbon-containing wastes while in the rotary kiln reactor 102. Alternatively, instead of water, steam may be introduced to the hydrocarbon-containing wastes while in the rotary kiln reactor 102.
Upon entering the preheated rotary kiln reactor 102, a small amount of volatile matter from the hydrocarbon-containing wastes is instantly vaporized. Due to the rotary kiln reactor 102 being preheated to the volatile matter's flash point of combustion, the volatile material is instantaneously ignited when contacted with air or some other oxygen-bearing gas. For the present gasification methodology, the quantity of oxygen-bearing gases introduced along the length of the rotary kiln reactor 102 is far below that required for complete combustion of the hydrocarbon-containing wastes. The quantity of oxygen-bearing gases may be in the range of about 30% to about 70% percent by volume of that required for complete combustion of the hydrocarbon-containing wastes. The chemical composition of the hydrocarbon-containing wastes, the amount of moisture contained therein, and the intended temperature of the gasification reaction dictate the quantity of the oxygen bearing gases.
During gasification, four distinct zones of gas-sold reactions are created along a length of the rotary kiln reactor 102 and the corresponding temperature in each of the zones results from partial combustion of vaporized volatile matter of the hydrocarbon-containing wastes and the gasification reactions between the vapors of water and hydrocarbon-containing wastes. The four zones result from controlling the fraction of total oxygen bearing gases allowed to enter the rotary kiln reactor 102.
The wastes generated by industry and manufacturing processes vary significantly in terms of their physical and chemical properties. In order to be able to process each of these wastes separately or in combination, suitable reaction conditions within the rotary kiln reactor 102 to align with the requirements of the wastes should be provided. The physical properties of hydrocarbon-containing wastes generally relate to size, density, and their moisture content. The physical properties require that the wastes are allotted certain residence time within the rotary kiln reactor 102 in order for the wastes to fully react with gaseous reactants within the bounds of the rotary kiln reactor 102. The ability of the present disclosure to increase localized temperatures within zones of the rotary kiln reactor 102 speeds up reactions within the rotary kiln reactor 102. In this manner, the apparatus 100 of the present disclosure is able to accommodate variations in the physical properties of received hydrocarbon-containing wastes.
In contrast, the chemical properties of the hydrocarbon-containing wastes are characterized by their elemental compositions and their volatility as determined by amount of volatile carbon content and fixed carbon contained within the wastes. The elemental composition determines the amount of oxygen-bearing gases as well as amount of water required to fully gasify the waste. The volatility dictates where the reaction gases are introduced for effective gasification of the waste. For example, a mixture of plastic waste and char includes almost 50% volatile carbon and 50% fixed carbon whereas textile waste includes of mostly volatile carbon. For gasification of plastics and char mixture, a gradual introduction of oxygen-bearing gases along the length of the rotary kiln reactor 102 is an effective mode for gasification. The reason for gradual introduction of reactant gases is that the volatile carbon has a tendency to instantly react with the reactant gases whereas the fixed carbon requires longer contact time with reactant gases for gasification reactions to take place. The rotary kiln reactor 102 of the present disclosure has the ability to introduce the reactant gases according to the dictate of the waste along the length of the rotary kiln reactor 102 through the zoned gas distributor 108. For textile waste, an effective mode for gasification includes introduction of most of the requisite oxygen-bearing gases and water in the zone close to where the waste is introduced into the rotary kiln reactor 102. Thus, in this case all oxygen-bearing gases may enter in the first zone of the gas distributor 108.
The following paragraphs describe an exemplary application of the present disclosure for gasification using hydrocarbon-containing wastes containing almost equal parts of volatile carbon and fixed carbon. As the below is merely an exemplary application, it is not meant to be limiting. One skilled in the art should appreciate the present disclosure providing an endless number of reaction conditions within the bounds of the rotary kiln reactor 102 in order to accommodate all types of gas/solid reactions required for efficient gasification of varied-source hydrocarbon-containing wastes.
In the following example, waste containing about equal parts of volatile carbon and fixed carbon is processed in a first zone, which may be closest to the entry of the hydrocarbon-containing material into the rotary kiln reactor 102, the temperature is maintained below about 800° F. so the moisture contained in the hydrocarbon-containing material is evolved first, followed by partial evaporation of the volatile matter. In the first zone, about 10% to about 25% of the oxygen-bearing gases are introduced. In the first zone, the following reactions represent the interactions between the gas(es) and solid hydrocarbon-containing wastes:
Hydrocarbon-Containing Material+Hot Gases→Volatile Matter+Steam Volatile Matter+Air→CO2+CO+H2+H2O+Hydrocarbons
In the second zone, another about 10% to about 25% of the oxygen-bearing gases are introduced to further combust the volatile matter, which continues to vaporize. In the second zone, the temperature is allowed to rise to about 1000° F. to about 1200° F. The objective of the second zones configuration is to completely vaporize the volatile matter from the hydrocarbon-containing material.
In the third zone, another about 25% to about 40% oxygen-bearing gases are introduced and directed towards the hydrocarbon-containing material, which should now be devoid of volatile matter but including fixed carbon and inorganic components of the hydrocarbon-containing wastes. The configuration of the third zone allows for full combustion of the fixed carbon. In the third zone, the temperature is allowed to rise to a range of about 1800° F. to about 2000° F. in order to accelerate combustion of the fixed carbon. The heavy hydrocarbons and the combustible gases present inside of the rotary kiln reactor 102 at the third zone also partially combust with the oxygen-bearing gas. The vapors of water present in the gas inside the rotary kiln reactor 102 at the third zone also react with the fixed carbon as well as with the heavy hydrocarbon molecules present in the vaporized volatile matter, thereby causing these molecules to break down into smaller hydrocarbon molecules and combustible gases comprising mainly carbon monoxide and hydrogen. In the third zone, the main reactions are as follows:
C+O2CO2
CO+H2+O2+Heavy Hydrocarbons→CO2+H2O+CH4+C2H6+CO+H2
In the fourth zone and subsequent zones (if any), conditions similar to those in the third zone are maintained with respect to the temperature and the amount of oxygen-bearing gases introduced therein.
For example, if the hydrocarbon-containing waste was replaced by waste containing almost all volatile carbon, 100% of the oxygen-bearing gases would enter in the first zone of the gas distributor 108 and all of the gasification reactions would take place within the first zone.
Not all components of the apparatus 100 are necessary for all processing functions and therefore only pertinent components of the apparatus 100 may be utilized depending upon the processing function carried out by the apparatus 100. Idle components of the apparatus 100, not utilized during particular processing functions, may simply be bypassed, thereby not impacting the efficiency of the specific processing function in any way.
Referring to
Gases introduced into the gasifer/apparatus 100, gases generated by reaction of the introduced gases with the hydrocarbon-containing wastes, and reacted ash generated in but not otherwise disposed of by the gasifer/apparatus 100 are directed to a cyclone 406. Additionally, solids/ash enter the cyclone 406 at a rate commensurate with the presence of a non-combustible fraction present in the hydrocarbon-containing waste. These gases and ash may have a temperature of about 1800° F. At the cyclone 406, at least a portion of the received ash is separated from the gases, and the ash is dispelled from the system. The gases remaining in the cyclone 406 may be cooled by two methods before they are utilized as source of energy. One method of cooling occurs by means of direct contact with water in a quencher 408. An alternative method for cooling the gas is by using an indirect means of contacting the gas with water in a Waste Heat Exchanger (“WHE”) 414.
Upon exiting the quencher 408 or upon exiting the WHE 414, the gas is further purified to remove additional ash using either a cyclone 410 or filter 416 before it is utilized by, for example, a burner 412. By way of example, a surge tank 418 is included in the system 400 to mitigate surges in production of fuel gas from the gasification of hydrocarbon-containing wastes because of its variability with respect to physical and chemical properties.
For example, the gases may have a temperature of about 1800° F. upon entering the quencher 408 and a temperature of about 350° F. upon exiting the quencher 408. The gases may have a substantially constant temperature during transfer between the quencher 408 and burner 412, and between the WHE 414 and the burner 412. For example, the constant temperature may be about 350° F.
The gases may be about 1800° F. while entering the WHE 414 and may be about 350° F. while leaving the WHE 414. Lime may be introduced into the filter 416 to remove contaminants therein.
Attention should now be given to
At block 504 solid residues resulting from the gasification of hydrocarbon-containing wastes are separated from the gases generated from the gasification of the hydrocarbon-containing wastes. This may be performed using the cyclone 406. At block 506 gaseous hydrocarbon-containing wastes are quenched using direct contact with water. Quenching of the gaseous hydrocarbon-containing wastes may be performed using the quencher 408. At block 508 additional solid residues are separated from the quenched gases generated from the gasification of the hydrocarbon-containing wastes. This may be performed using the quencher cyclone 410. At block 510 the separated gases are combusted. Combustion of the said gases may be performed using the burner 412.
At block 512 thermal energy is captured by indirect means from hot gases generated from the gasification of hydrocarbon-containing wastes. This may be performed using the WHE 414. At block 514 additional solid ash is separated from the hydrocarbon-containing wastes. This may be performed using the filters 416. At block 516 the gases generated by the gasification of hydrocarbon-containing wastes are combusted as illustration of one utility of fuel gases generated by gasification of the hydrocarbon-containing wastes. This may be performed using the burner 412. Alternative options for utilization of the gases are direct replacement of fuels in industry and manufacturing processing, direct replacement of fuels in boilers for generating steam, and direct replacement of fuels in gas engines for generating electricity.
Referring now to
The distinguishing characteristics between the waste types in
The above teachings of the present disclosure are meant to be illustrative. They were chosen to explain the principles and application of the disclosure and are not intended to be exhaustive or to limit the disclosure. Many modifications and variations of the disclosed embodiments may be apparent to those of skill in the art. Moreover, it should be apparent to one skilled in the art, that the disclosure may be practiced without some or all of the specific details and steps disclosed herein.
The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It should, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the disclosure as set forth in the claims.
This application claims priority to U.S. Provisional Patent Application Ser. No. 62/040,943, which is incorporated herein by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2015/046257 | 8/21/2015 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62040943 | Aug 2014 | US |
