DESC:BIOMASS FUELED FURNACE WITH AMMONIA CRACKER UNIT

TECHNICAL FIELD

[0001] The present invention relates to a furnace assembly that operates at reduced atmosphere, in particular, to a furnace operating in the absence of oxygen, and only in the presence of nitrogen and hydrogen. The invention particularly relates to bio-fuel based furnace with ammonia cracker unit for sintering and annealing process.
BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Sintering is the process of forming materials and components from a powder under the action of thermal energy. The process of sintering heats the compacted part to fuse the loosely bonded particles for improved strength and hardness. The temperature used for sintering is below the melting point of the major constituent of the powdered metal material. The sintering process is governed by several material and process variables including temperature and time, powder particle morphology, density and other sintering parameters (viz. time-temperature-atmosphere).
[0004] The selection of a sintering atmosphere is most often dictated by the choice of material, desired properties, part design, production demands and applications. The actual choice of atmosphere viz. vacuum, pure gases, mixtures, blended gases, generated gases, etc. must always be taken into consideration due to its influence on final properties. The purpose of this atmosphere is to aid in lubricant removal from the compact, reduce residual surface oxides and protect the compacts from oxidation during the sintering process. Atmosphere requirements in a sintering furnace vary considerably depending on the type of furnace, style of furnace and if delubrication is required to be performed. The most common sintering atmospheres are mixtures of nitrogen/ hydrogen or dissociated ammonia diluted by nitrogen additions. H2/ N2 ratios vary from as low as 5-7% to as high as 20-30% hydrogen.
[0005] The atmosphere in sintering furnaces with gases are created with the help of gas generators. There are three types of gas generators viz endothermic gas generators, exothermic gas generators and ammonia cracker. Ammonia crackers are used for the generation of hydrogen and forming gas. Here, hydrogen and nitrogen are generated in a cost-effective way in a pre-determined volume and weight ratio. The ammonia gas is cracked in the cracker unit of the main furnace.
[0006] Usually the most common fuel source for modern furnaces is natural gas; other common fuel sources include LPG (liquefied petroleum gas), fuel oil, wood and in rare cases coal. Currently, more than 40 TWh of oil and electricity are used for heating purposes. Usage of oil and other fossil fuels for electricity are expensive and always leads to emission of carbon, which are harmful to environment. Electric fired furnaces have disadvantages such as excessive cost though it is not carbon neutral.
[0007] Most of electricity is generated by thermal plants in India. NTPC has 24 coal based plants with installed capacity of 45410 MW in addition to many other plants. Thermal power is the biggest source of power in India, comprising about 70% of total energy consumed. There are two main disadvantages associated with this viz. these plants are based on fossil fuel and add to global warming by adding carbon dioxide in the atmosphere. Industries using such furnaces have to pay heavy electricity bills seriously affecting the viability.
[0008] Alternatively, the benefits of renewable energy sources are not only environmental and economical, but also important from the point of view of the security, especially for those countries that are strongly dependent on foreign oil import.
[0009] Biomass as a replacement for the conventional fossil fuel is getting attractive because it is renewable and is a clean source of energy. Biomass is a hydrocarbon material which consists of carbon, hydrogen, nitrogen, oxygen and a certain amount of sulphur too. It also contains certain amounts of mineral matters that eventually generate ash. Biomass can be considered as a carbon-neutral source. The term neutrality refers to the simultaneous formation of CO2 through smelting and absorption by biomass.
[0010] Accordingly, the present invention uses carbon neutral fuel in place of fossil fuel, reducing global warming, and thus reducing the electricity bills drastically making industries more profitable. The present invention discloses a design for a fumace that can use carbon neutral fuel i.e. bio pellets in specially designed burners to heat modified furnace and ammonia cracker. The furnace has a state of art design to achieve and control the temperature variation within 5 degrees through its various novel features including furnace design, auto variable speed burners and damper air flow system.
[0011] Therefor the present disclosure overcomes the above mentioned problem associated with the traditionally available method or system, any of the above mentioned invention can be used with the presented disclosed technique with or without modification.
[0012] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0013] In some embodiments, the numbers expressing quantities or dimensions of items, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0014] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
OBJECTS OF THE INVENTION
[0015] The primary objective of the present invention is to provide a cost-effective, eco-friendly and efficient fumace assembly operating at reduced atmosphere for sintering and/or annealing processed used in the metallurgy and similar other industries.
[0016] Yet another objective of the present invention is to provide a plurality of specially designed auto variable speed burners for the fumace wherein each of the burners is a biofuel-based burner, which uses bio-pellets for producing heat. Further, consumption or supply of the bio-pellets inside the burners can be controlled automatically to control temperature inside the furnace housing as per the requirements.
[0017] Still another objective of the present invention is to provide a damper air flow system in the furnace to achieve a temperature as high as 920° in the furace, and 900° in ammonia cracker with the bio-pellets as source; and further different temperatures at different locations inside the furnace housing.
[0018] Still another objective of the present invention is to provide a specially design ammonia cracker unit for the supply of nitrogen and hydrogen inside the furnace for sintering and/or annealing process.
SUMMARY
[0019] The present invention discloses a biomass fuelled furnace for the purpose of sintering and/or annealing process equipped with a uniquely designed ammonia cracker unit. The furnace as disclosed according to one of the embodiments of the present invention, operated in a reduced atmosphere, i.e. absence of oxygen, with nitrogen and hydrogen present inside the furnace for sintering or annealing process. Further, the furnace includes a furnace muffle and a plurality of bumers configured with the furace housing, wherein each of the burners is a biofuel-based burner, which uses bio-pellets for producing heat.
[0020] According to another embodiment of the present invention, the furnace incorporates a damper air flow system configured with the furnace housing, the damper air flow system being provided to achieve a temperature as high as 920° in the furnace, and 900° in ammonia cracker with the bio-pellete as source; and further different temperatures at different locations inside the furnace housing. The furnace muffle is filled with the nitrogen and hydrogen, which are supplied from an ammonia cracker.
[0021] In yet another embodiment, the burners are auto variable speed burners, i.e. consumption or supply of the bio-pellets inside the burners can be controlled automatically to control temperature inside the furace housing as per the requirements. The damper assembly in the furnace and ammonia unit is designed in such a way that there is no restriction in the exhaust air flow. In other words, a temperature as high as 900-920° in the furnace and cracker unit could not have been achieved with such restrictions in the exhaust air flow.
[0022] Another embodiment of the present invention provides an ammonia cracker unit (100). The ammonia cracker unit comprising of a cylindrical retort and a plurality of biomass fuelled burners wherein the retort is filled with Nickel catalyst for cracking ammonia gas at 900° C.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] A general understanding of the invention with its foregoing and other objects will be apparent upon consideration of the following detailed description read in conjunction with the accompanying drawings.

[0024] Figure 1 represents a diagrammatic representation of the ammonia cracker unit in accordance with one of the embodiments of the present disclosure.

[0025] Figure 2 shows a top view of the annealing furnace in accordance with another embodiment of the present disclosure, and

[0026] Figure 3 shows a side view of the annealing furnace in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0027] Accordingly, while carrying out the above objects, the present invention provides a biomass based sintering/annealing furnace with ammonia cracking unit which is economical, efficient and uses direct heat from the first source of fuel viz. biomass / coal.
[0028] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure).
[0029] Thus, for example, it will be appreciated by those of ordinary skill in the art that the diagrams, schematics, illustrations, and the like represent conceptual views or processes illustrating systems embodying this invention.
[0030] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0031] According to one of the embodiments of the present invention, the disclosed furnace. includes a biomass fuelled ammonia cracker unit (100). The ammonia cracker unit (100) comprises of a cylindrical retort (103) and a plurality of biomass fuelled burners (101 and 105). The said ammonia cracker retort (103) is filled with catalyst (106) viz. Nickel, which cracks ammonia gas, entering from the inlet (102), at 900° C, into nitrogen and hydrogen at a ratio of 1:3. The cracker gas then passes the heat exchanger for cooling and for pre heating the incoming gas. The gas may be further purified depending on the requirement.
[0032] In another embodiment, specifically designed biofuel pellet burners (104 and 105) are used to get homogenous temperature around the retort (103) and crack the gas. In one embodiment, the cracker capacity is 60 Nm ³/hr.
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[0033] According to yet another embodiment, the present invention discloses an annealing furnace (200), whose top view and side view are represented in Figure 2 and 3 respectively. An annealing furnace works by heating a material above the recrystallization temperature and then cooling the material once it has been held at the desired temperature for a suitable length of time. There are three stages in an annealing furnace namely recovery, recrystallization and grain growth.
[0034] The furnace unit (200) includes a furnace muffle and a plurality of biomass fuelled burners (201) configured with the furnace housing (202). The said burners (201) are configured to produce heat inside the housing for heating a material passing through the muffle housing. which uses bio pellets for producing heat. These are auto variable speed burners, which means that the consumption or supply of the bio-pellets inside the burners can be controlled automatically to control temperature inside the furnace housing as per the requirements. In one embodiment, the air flow also be controlled here.
[0035] Further, the furnace muffle is filled with the nitrogen and hydrogen, which are supplied from the ammonia cracker unit (100). The use of hydrogen gas here is to provide reducing atmosphere inside annealing furnace.
[0036] In yet another embodiment of the present invention, the furnace (200) further includes a damper air flow system configured with the furnace housing, the damper air flow system being provided to achieve different temperatures at different locations inside the furnace housing.
[0037] The furnace (200) design disclosed hercin has very specific temperature control, and controls temperature variation within 5 degrees due to its design, auto variable speed burner and damper air flow system.
[0038] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
[0039] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.

CLAIMS:

We Claim:
1. An apparatus for biomass fuelled furnace with ammonia cracker comprising of;
a biomass fuelled ammonia cracker unit(100), wherein the ammonia cracker unit (100)comprising of a cylindryical retort(103) and plurality of biomass fulled burners(101) and (105);
the ammonia retrot (103)is filled with catalyst(106) which cracks ammonia gas entering from inlet (102)at 900°C into hydrogen and nitrogen at a ratio of 1:3;
a plurality of biofuel pellet burners(104 and 105), wherein the biofuel pellet burners are used to get homogenous temperature around the retort(103) and crack the gas;
an annealing furnace(200), wherein the annealing furnace works by heating a material above the recrystallization temperature and then cooling the material once it has been held at the desired temperature for a suitable length of time;
a furnace unit(200), wherein furnace unit comprising of a furnace muffle and a plurality of biomass fuelled burners (201)configured with the furnace housing(202);
2. The apparatus for biomass fuelled furnace with ammonia cracker as claimed in claim 1, wherein the catalyst is Nickel(106).
3. The apparatus for biomass fuelled furnace with ammonia cracker as claimed in claim 1, wherein the cracker gas passes the heat exchanger for cooling and for pre heating the incoming gas and the gas may be further purified depending on the requirement.

4. The apparatus for biomass fuelled furnace with ammonia cracker as claimed in claim 1, wherein the cracker capacity is 60 Nm ³/hr.
5. The apparatus for biomass fuelled furnace with ammonia cracker as claimed in claim 1, wherein there are three stages in annealing furnace such as recovery, recrystallization, and grain growth.
6. The apparatus for biomass fuelled furnace with ammonia cracker as claimed in claim 1, wherein the burners in furnace unit are configured to produce heat inside the housing for heating a material passing through the muffle housing which uses bio pellets for producing heat.
7. The apparatus for biomass fuelled furnace with ammonia cracker as claimed in claim 1, wherein the burners in furnace are auto variable speed burners, which means that the consumption or supply of the bio-pellets inside the burners can be controlled automatically to control temperature inside the furnace housing as per the requirements and the air flow also be controlled.
8. The apparatus for biomass fuelled furnace with ammonia cracker as claimed in claim 1, wherein the furnace muffle is filled with nitrogen and hydrogen and the use of hydrogen gas reduces atmosphere inside annealing furnace.
9. The apparatus for biomass fuelled furnace (200)with ammonia cracker as claimed in claim 1, wherein the furnace comprising of a damper air flow system configured with the furnace housing, the damper air flow system being provided to achieve different temperatures at different locations inside the furnace housing.

10. The apparatus for biomass fuelled furnace with ammonia cracker as claimed in claim 1, wherein the furnace comprising of specific temperature control, and controls temperature variation within 5 degrees due to its design, auto variable speed burner and damper air flow system.