Title of Invention

BOILER FURNACE WHICH AVOID THERMAL NOX

Abstract

The present invention relates to a boiler furnace which avoid NOx and increase thermal efficiency with small boiler. For this purpose, the boiler furnace according to the present invention has a outer water walls and inner water walls. All of the water walls contain water which absorb heat from flame and cool the water tube which act as a container, passage, evaporator of water and water walls with membrane that connect water tubes each other. The spaces between outer water walls and inner water walls make pipe shape space which contain fire and avoid making fire ball which produce nitrogen oxides due to high temperature induced from concentrating of flame.

Full Text

BOILER FURNACE WHICH AVOID THERMAL NOx Technical Field The present invention relates to a boiler furnace to generate electricity. Background of the invention There are two kinds of boiler furnace. One is home type and the other is electric generating type. Home boiler produces warm water with low pressure. Electricity generating boiler produces high pressure steam. By above requirement, each structure and system are quite different, For the home boiler, single fuel injector is installed at the bottom facing the top or installed on the top facing the bottom in the furnace surrounded by water walls. For the electricity generating boiler, a lot of fuel injectors are installed in centrifugal direction form in the furnace surrounded by water walls. As shown in Figl, In the conventional centrifugal boiler furnace, the said space(l08) acts as a burning space of fuel because fuel sprayed from the said fuel injector burns within the space(lOB) surrounded by said water walls(104). The flame which is formed during burning of fuel sprayed from each fuel injector gets together into the empty space(U)ft), and then it becomes a big cylindrical flame (110) and the central part of the flamed 10)bccornes a fire ball 012) with high temperature. The temperature of fire ball goes up to above lOOO'C. This high temperature combines the nitrogen and oxygen in the air and produce a lot of nitrogen oxides (called thermal NOx), environmental toxic substances. To provide tall super heating structure, economizer, air preheater. dust collector above*, the furnace and extra NOx treating facilities on the ground, tremendous construction fees arc required. There is another problem with ash in case of using solid fuel such as coal in the conventional boiler furnace. The ash which has been burnt and left behind is melted by hot fire balKl 12) and become sticky clinker which adheres to the water tubes and lowers thermal conductivity. Summary of the invention Accordingly, the present invention has been made in an effort to avoid thermal NOx. Another object of the present invention is to provide a smaller boiler with high thermal efficiency. In order to achieve the above objectives, the boiler furnace according to the present invention consisting of outer water walls with spray nozzle to AHEMDEfsllEET(ART.34) inject fuel and air at each corner of water walls is characterized in supplemental water walls which are placed in the space surrounded by outer water walls and are located in the assumed fire ball (1.3)location. The small space surrounded by supplemental water walls can be utilized as a useful space, like as pre-heater, economizer. Therefore, the boiler furnace of the present invention avoid fire hall and makes low flame temperature, and avoid producing of thermal NOx and provide more heat transferring to water due to preparing of larger contact surface and can lead to small boiler with higher efficiency. The flames going ahead to center of the big space surrounded by outer water walls are reflected by inner water walls and returned to outer water walls and heat the water in the outer water walls. During reflecting by inner water walls, the thermal energy of the flame transfer to water in the inner water walls. More heat transferring to water walls is achieved by shortening the distance from flame to outer water walls and additional heating by inner water walls. Thermal NOx is avoided by preventing of fire ball and making fire pipe which have lower flame temperature even though it has maximum combustion efficiency. Brief description of Drawings Figl is a horizontal cross sectional view illustrating one of the current boiler furnace. Fig 2 is a local cut, perspective view illustrating a of present invention. Fig 3 is a plain view illustrating a first embodiment for the arrangement of outer water walls and inner water wall installed in boiler furnace. Fig 4 is a plain view illustrating a second embodiment for the arrangement of outer water walls and inner water wall installed in boiler furnace. Fig 5 is a perspective view illustrating inner water wall which show arrangement of air injection hole formed at the membranes between water tubes. Fig 6 is a cross sectional view of inner water wall illustrating the direction of air injection holes prepared at the membrane. Fig 7 is a cross sectional view of arrangement of inner water walls of another embodiment which is installed in boiler furnace of present invention. fcj"^ ...■ _ r.„ ., IMBIk ...... trT— rm m_ Detailed Description of the Invention Present invention is explained in detail by using of attached figures. Fig 2 is a perspective view of cut. away boiler furnace belongs to present invention. Boiler furnace related to present invention is composed of inner and outer water walls(6,10) and combustion space (s) between outer water wall(6) and inner water walls (10) is as shown said Fig2. Said outer water wall (6) is composed of numbers of parallel water tubes and membranes which connect and seal water tubes in parallel and the outer water wall is located along outer boundary of boiler furnace and thermal insulator (8) is inserted between the outer water wall(6) and wall (4)of the furnace. Said inner water wall (10) composed of numbers of water tubes and membranes which connect, and seal water tubes in parallel is located in the outer water wall, Said required combustion spacc(s) is provided by adjusting space between outer water wall (6)and inner water wall(lO). Water tubes which construct water walls contain flowing waters. Water flows from water supplying header(fia(6b) located at bottom through water wall U) steam receiving header (10a,10b) at top of water wall. Super heater tubesl not illustrated) are installed above the steam header(lOaJOb). It is desirable to make outer water wall(6) to be sloped inward with reduced diameter along the height and to make inner water wall(.10)lo be sloped outward with growing diameter along the height like as trumpet because this arrangement makr\s wider combustion space below and narrow combustion space upper and make more combustion with more heat radiation at lower level and more convective heat to the increased surface on outer water wall and inner water wall at lower level and above water wall prepared by sloped water wall (6,10) at higher level lead to more heat absorption at the furnace and resulted in lower super heater with less construction fee. The cross sectional shape of outer water wall (6)can vary according to the shape of combustion room(2)l like as conventional rectangular, polygon as shown Fig 3 and circular as shown Fig 4. Numbers of fuel injection nozzles(l2) are arranged with required intervals on the outer water wali(6) and are aimed to the tangential direction to the inner water wall. Above arrangement and direction of fuel nozzle(12) provide even big fire pipe (F)in the combustion space (s) between outer and inner water wall(10,6) and heal the flowing waters in the inner and outer water walls, On the other hands, It is desirable to make inner water wall(lO) circular cross section as shown in Fig3 and Fig 4 as available because circular shape make fire pipcOO better and increase the heat absorption efficiency in the combustion space(s) because it makes betLer rotational contact of fire pipe along the inner water wall . Numbers of air injection holes(14)are provided at the inner water wall as shown in lvig5 and Fig6 and are formed at the membranes (lOd)which connect and seal the gaps between water tubes in parallel and the air injecting holes(l4) are formed slope up at the membrane as shown in Fig6. Said air injection holed4) inject preheated, compressed air which come from air prcheater and air push pump to the combustion space(S) between inner water wall and outer water wall and assist mixing of air and fuel and makes low flame temperature and prevent heating up to NOx forming temperature keeping best thermal efficiency. Fig 7 is across sectional view of another embodiment of inner water walls (10) which are composed of multi-curved water walls and are arranged centrifugally with required intervals. Air injecting holes(14) at the membrane between water tubes ar« avoided automatically for the inner water wall(lO) shown at Fig7 because gaps(lQf) between each separated water wall(JOe) do the role of air injecting holes(l4). Following is the explanation of operation for the boiler furnace of present invention. Fill water in all the water tubes and begin fuel injecting to the combustion space(S) through nozzles(12) which are located at outer water wall(6) and are directed to tangential to the inner water wall(10) and ignite fire and wait until the fire yrow vigorously and open air valve which supply air to the inside of inner water wall (10) and control the air which are injected into combustion space(s) from inside of inner waler WHH(IO). According to above sequence, flame(F) grows and fill the combustion space(S)and are shaped to fire pipe thanks to the restraint by both water walls(6,10). Accordingly, the said flame(F) rotate along the inner water wall(lO) in the combustion space(S) between inner and outer water walls(6,10) and the flamed7) in said combustion space(S) do not grow to high temperature because concentration of flame be avoided and cooling air are supplied from air injecting holed4) of inner water wall(lO). Therefore, boiler furnace according to present invention do not cause problem of formation of nitrogen oxides which come from oxidation of nitrogen in the hot air due to the high temperature of flame. On the other hands, H is desirable to apply coating of wear resistant material to overcome the erosion come from deflection of flame and short distance from flame to both water walls which accompany particle impinging because the flame include particles like as ash. As described above, boiler furnace according to present invention makes flame a fire pipe which rotate along the combustion space between the inner and outer water walls(6,10) and air injected from air injection holes(14) prepared at inner water wall makes best mixing of air and fuel and makes maximum combustion efficiency arid prevent too high temperature which promote formation of nitrogen oxides and pipe shaped flame heats the inner and outer water walls at both sides and provide high water temperature and more evaporation in the water tubes. Since, boiler furnace according to present invention gives not only preventing of thermal NOx but also gives combines several other effect like as more evaporation of water due to more surface to receive heat, rotating of pipe shaped flame, higher density of flame in the restraint space, closed distance between flame and water walls and preventing of accumulation of thermal insulating clinker:? on the surface of water tubes. Industrial Applicability According to the present invention, thermal NOx can be significantly reduced, and also the scale of boiler construction is reduced significantly because the efficiency of boiler is increased with lower super heating structure. IPEA/KR 0*0?. MM. Claims Claim 1,2,3.1,5,67.8 were cancelled Claim 9 : added Boiler furnace composed of outer water wall(6),inner water wall(lO). and annular space(S) between inner water wall and outer water wall(6). Said outer water wall(6) is installed along the periphery of the furnace wall(4) and thermal insulators(8) are inserted between outer water wall(6)and furnace wall(4). Said inner water wall (10) is installed in the outer water wall(6). Said outer water wall(6)and inner water wall(lO) are composed of numbers of tubes which are arranged parallel and numbers of membranes which are arranged between tubes and connect tubes and seal the gaps between tubes arranged parallel. Numbers of fuel injection nofc£les(12) are arranged with required intervals at the said outer water wall(fi)and are aimed to the tangential direction to the said inner waterwall(lO), Numbers of air hole(14) are prepared at the membranes of the said inner water wall (10)which is coated by erosion resistant materials. Claim 10 : added Boiler furnace where inner water walls(lO) which are composed of multi-curved water walls and are arranged centrifugally with required intervals as shown in Fig 7, are not composed of a circular type inner water wall as shown in Fig3 and Fig 4. in claim 9. PCT/HR2GQ5 00 2 957 I 0.1 0. 2006. Claims H;iims 1,2.3.4.5.6.7,** w claims 9 ' added Boiler furnace composed of outer water wall(6X inner water wall(lO) and annular space(s) between inner water wall(lO) and outer water wall(6). Said outer water wall(6) is installed along the periphery of the furnace wall(4) and thermal insulators(S) are inserted between outer water wall(6) and furnace wall(4). Said inner water wall(lO) is installed in the outer water wall(10).Said outer water wall(lO) and inner water wall(lO)are composed of numbers of Lubes which are arranged parallel and numbers of membranes which are arranged between tubes and connect tubes and seal the gaps between tubes arranged parallel. Numbers of fuel injection nozzles(12) are arranged with required intervals at the said outer water wall(6) and are aimed to the tangential direction to the said inntsr water walHIO). Numbers of air holc(l4) are prepared at the membranes of the said inner water wall UOwhich is coated by erosion resistant materials . Claim 10. added Boiler furnace where inner water wa)ls(lO) which are composed of multi-curved water walls and are arranged , radially, centrifugally with required intervals.

Documents:

0883-chenp-2007-claims.pdf

0883-chenp-2007-correspondnece-others.pdf

0883-chenp-2007-description(complete).pdf

0883-chenp-2007-drawings.pdf

0883-chenp-2007-form 1.pdf

0883-chenp-2007-form 26.pdf

0883-chenp-2007-form 3.pdf

0883-chenp-2007-form 5.pdf

0883-chenp-2007-pct.pdf

883-chenp-2007 form-3 09-12-2010.pdf

883-CHENP-2007 POWER OF ATTORNEY 09-12-2010.pdf

883-CHENP-2007 AMENDED CLAIMS 31-10-2011.pdf

883-CHENP-2007 AMENDED PAGES OF SPECIFICATION 31-10-2011.pdf

883-chenp-2007 correspondence others 09-12-2010.pdf

883-CHENP-2007 EXAMINATION REPORT REPLY RECEIVED 31-10-2011.pdf

883-CHENP-2007 FORM-13 31-10-2011.pdf

883-CHENP-2007 POWER OF ATTORNEY 31-10-2011.pdf

883-chenp-2007 correspondence others-23-06-2009.pdf

883-chenp-2007 form 13 05-05-08.pdf

883-chenp-2007 form-26.pdf

883-chenp-2007 form-3.pdf