Title of Invention

NEW EXHAUST GAS BOILER ON DG SET

Abstract

A novel exhaust gas boiler heat exchanger with less than 22.75 litres of water hold up comprising an enclosure (1) for passing the hot exhaust gas from exhaust of a DG set, a primary heat exchanger (2) disposed with the said enclosure for passing cold intermediate fluid selected from air , water, and organic or inorganic liquids, a secondary heat exchanger (3) in closed loop with the said primary heat exchanger, a feed water pump (4) for said secondary heat exchanger, the arrangement being such that the hot exhaust gas exchanges heat with the cold fluid in the primary heat exchanger, the hot fluid exiting the primaiy heat exchanger flows through said secondary heat exchanger to the feed water in the feed water unit, thereby exchanging heat thereto and producing hot water or steam.

Full Text

THE PATENT ACT, 1970 COMPLETE SPECIFICATION (SECTION-10) TITLE "New Exhaust Gas boiler on DG Set" APPLICANTS M/S. THERMAX LTD., D-13, MIDC Industrial Area, Chinchwad, Pune - 411 019 Maharashtra, India, an Indian Company. The following spedfication particularly describes and ascertains the nature of this invention and the manner in which it is to be performed. NEW EXHAUST GAS BOILER ON DG SETS tntroduction to the Field of invention: This invention relates to a new exhaust gas boiler on DG sets. This invention more particuiarty relates to the development of an exhaust gas boiler in which the water holdup does not exceed 22.75 litres. Prior Art and Drawbacks: It is already known in the prior art to generate steam, using heat in the DG set exhaust. And in these conventional exhaust gas boiler (EGB), it is known to generate steam by exchange of heat from hot e)diaust gases of diesel engine to the water/steam with poof tailing as steam generating phenomena. In this process, the heat transfer coefficient ranges from 15 to 50 kcal/h.m C. Hence the water holdup invariably exceeds 22.75 litres. The main limitation of the prior art is that the water hold-up of the pressure part exceeds 22.75 litres bringing this unit under purview of Indian Boiler Regulations Act (IBR). The conventional prior art also suffers from higher capital cost of the exhaust gas trailer. Objects of the Invention: It is the principal object of this invention to propose a new design or improvement in the existing exhaust gas trailer design. It is another object of this invention to propose the use of an intermediate fluid which primarily absorbs/exchange the heat with the hot exhaust gases of diesel engine. It is also an object of this invention to propose that the heat absortrad/exchanged by the intermediate fluid to be rejected to the water/steam in the new heat exchanger/steam generator to generate steam It is yet another object of this invention to propose a new heat exchanger/steam generator design in which the heat transfer coefficient is in the range of 400 to 3000 kcal/m^° C and hence being able to maintain the water holdup below 22.75 litres. Thus out of the purview of IBR. FURTHER DISCUSSION OF PRIOR ART. We are aware of the following prior art i.e. German Patent 19837269 and Japanese Patent 10288306. The above two patents have t)een analyzed and we observe as follows. German Patent DE 19837269 - This Patent primarily relates to cleaning of exhaust gas or domestic oil or gas fired water heaters. This is carried out by water sprays, which takes care of the pollutants. The exhaust gas is cooled as it passes over a heat exchanger and then passes through a mist of fine water droplets, which creates a thermal shock on the gas and leads to an effective solution of the pollutants. The apparatus is used as a water collection source with a tank containing a heat exchanger. The heat exchanger uses boiler feed water as cxjoling medium and the water re-circulated to the sprays. This has nothing to do with the applicant's invention wherein the exhaust gas from a DG set (Diesel Generator set) is passed through an enclosure having heat exchanger within the enclosure, which heat exchanger is in closed loop with another heat exchanger outside the enclosure. There is no direct contact of the hot gases with droplets of water or the a)oling medium. The construction details are also entirely different. Japanese Patent 10288306 - This Patent relates to a circulated fluid esteem boiler equipment. The very first difference itself is that the equipment is comprised of a falling particle type heat exchanger, which is not print in the applicant's invention. High temperature particles compressor gas are supplied from a furnace in the Japanese Patent which form a high speed fluidized bed and a fluidized bed heat exchanger. High temperature particles are supplied from the falling particle type heat exchanger - high temperature particles are recycled to the falling particle type heat exchanger. It will thus be appreciated that the Japanese Patent is for an entirely different purpose and construction and we do not have any falling type particle heat exchanger. Thus none of the two citations either alone or in combination can destroy a novelty and inventive character of our invention. Brief Statement of the invention. There is provided a heat exchanger comprising an enclosure for passing the hot exhaust gas from exhaust gas of a DG set, a primary heat exchanger disposed within the said enclosure for passing cold intermediate fluid selected from air, water and organic/inorganic liquids, a secondary heat exchanger in closed loop with the said primary heat exchanger, a feed water pump for said secondary heat exdianger, the an'angement teing such that the hot exhaust gas exdianges heat with the cold fluid in the primary heat exchanger, the hot fluid exciting the primary heat exchanger flows through said se£X)ndary heat exchanger to the feed water in the feed water unit, thereby exchanging heat thereto and producing hot water/steam. There is also provided a method for the generation of steam from the exhaust gas of a DG set comprising the steps of passing a cold intermediate fluid selected from air, water and organic/inorganic liquids, passing the hot intermediate fluid in indirect heat exchange relationship with water in a steam generator, recycling the heat depleted intermediate fluid for further intermediate heat exchange With the flue gases in a closed loop and generating steam in the steam generator. Brief Description of the accompanvina drawings. In the acoimpanying drawings, the only Figure 1 schematically illustrates the novel steam generator. Detailed Description of the Drawings. Numeral 1 indicates the nonnal known shell/duct, capable of enclosing primary heat exchanger (2). The hot exhaust gases from the DG set are admitted through gas inlet (5) to pass though shell/duct (1) sweeping over the primary heat exchanger (2). The hot exhaust gases then exchange heat in the primary heat exchanger (2), which is integral with the shell/duct (1). The intermediate fluid (air, water and organic/nonganic liquids) is heated in the primary heat exdianger (2). This intermediate fluid is in a closed loop circuit with another heat exchanger/boiler (3) where it rejects heat to the feed water and thus generating steam. This heat exchanger/boiler (3) can be a single unit or several modular units connected in series or parallel. The heat depleted e)diaust gases exist the shell (1) through gas outlet (6). The heat exchanger 3 is provided with a feed water pump 4 to pump the water through the boiler (4). The steam produced in the boiler is excited through steam line 7. Advantages of the invention. Compact and less foot print. Out of the purview of Indian Boiler Regulations Act in single module for exhaust gas boiler upto 1250 KVA DG set and in multiple modules for exhaust gas boiler beyond 1250 KVA DG sets. Lower capital cost. Lower operational cost. Provides accessibility for water side cleaning. We Claim : 1. A novel exhaust gas boiler heat exchanger with less than 22.75 litres of water hold up comprising an enclosure (1) for passing the hot exhaust gas from exhaust of a DG set, a primary heat exchanger (2) disposed with the said enclosure for passing cold intermediate fluid selected from air , water, and organic or inorganic liquids, a secondary heat exchanger (3) in closed loop with the said primary heat exchanger, a feed water pump (4) for said secondary heat exchanger, the arrangement being such that the hot exhaust gas exchanges heat with the cold fluid in the primary heat exchanger, the hot fluid exiting the primaiy heat exchanger flows through said secondary heat exchanger to the feed water in the feed water unit, thereby exchanging heat thereto and producing hot water or steam. 2. A novel exhaust gas boiler heat exchanger substantially as herein described with reference to the accompanying drawings. 3. A method for the generation of steam from the exhaust gas of a DG set comprising the steps of passing a cold intermediate fluid selected from air, water and organic or inorganic liquids in indirect heat exchange relationship with the hot flue gases to generate hot intermediate fluid, passing the hot intermediate fluid in indirect heat exchange relationship with water in a steam generator, recycling the heat depleted intermediate fluid for further intermediate heat exchange with the flue gases in a closed loop and generating steam in the steam generator. DILIP WAMAN BAPAT ForTHERMAX LIMITED Dated this the 7* day of September, 2001.

Documents:

874-mum-2001-cancelled pages(3-5-2005).pdf

874-mum-2001-claims(granted)-(3-5-2005).doc

874-mum-2001-claims(granted)-(3-5-2005).pdf

874-mum-2001-correspondence(3-5-2005).pdf

874-mum-2001-correspondence(ipo)-(18-4-2005).pdf

874-mum-2001-drawing(12-9-2001).pdf

874-mum-2001-form 1(12-9-2001).pdf

874-mum-2001-form 19(12-3-2004).pdf

874-mum-2001-form 2(granted)-(3-5-2005).doc

874-mum-2001-form 2(granted)-(3-5-2005).pdf

874-mum-2001-form 26(14-3-2005).pdf

874-mum-2001-form 3(12-9-2001).pdf

874-mum-2001-form 5(14-3-2005).pdf

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