Specification
THE PATENT ACT, 1970
COMPLETE
SPECIFICATION
(SECTION-10)
TITLE
"AN IMPROVED FLUIDIZED THERMOSYPHON SYSTEM"
APPLICANT
M/S. THERMAX LIMITED, D- 13, MIDC INDUSTRIAL AREA, CHINCHWAD, PUNE-411 019. MAHARASHTRA, AN INDIAN COMPANY
The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed.
INTRODUCTION TO THE FIELD OF THE INVENTION
This invention relates to an improved method for an effective and economic way of using solid fuels in fluidised bed combustor with thermosyphon system.
This invention more particularly relates to the combination of Fluidised bed combustor which can burn a wide variety of conventional and non-conventional fuels more efficiently with a Thermosyphon system.
PRIOR ART ;
It is already known in the prior art that Thermosyphon systems are powered mostly by liquids fuels through burners and in rare cases through primitive solid fuel combustors like stationary grate etc.
DRAWBACKS OF THE PRIOR ART :
1. Higher fuel oil cost has compelled users a look for fuel shift options to solid fuels
2. Low combustion efficiency of primitive solid fuel fired system
3. In capability of primitive solid fuel fired systems to handle many non-conventional fuels
4. Incapability of primitive solid fuel fired system to capture pollutants like sulfur in the combustor itself.
OBJECT OF THE INVENTION :
It is therefore a primary object of this invention to propose an improved process for the optimum utilization of solid fuels in a fluidized bed combustor
It is another object of this invention to propose such a process which will be environmental friendly by producing less pollution by way of capturing sulphur during the process.
It is also another object of this invention to propose such a process which will have high thermal efficiency.
Yet another object of this is to propose a system which is combination of fluidized bed and Thermosyphon in a novel manner so as to be very compact with smaller foot print.
It is a further object of this invention to propose such a system which can utilize both conventional and non-conventional solid fuels and handling them effectively.
These and other objects in this invention will be apparent from the following paragraphs.
BRIEF STATEMENT OF THE INVENTION
Thus according to the invention there is proposed an improved Fluidized Bed Thermosyphon system comprising: a fluidised bed combustor capable of burning, a variety of both conventional and non-conventional solid fuels, a solid fuel feeder, a forced feed blower to blow air from below the bed to effect fluidisation to provide primary heat exchange, the combustor being a normal bubbling bed or a conventional circulating fluidised bed or a hybrid circulating fluidised bed and having optionally an in-bed heat exchanger connective/radiative heat exchanger utilizing common heat transfer medium like water, dowtherm inside heat exchange tubes for recovering heat from the flue gases, the connective/radiative heat exchanger being connected either in 'series' or in 'parallel' to the combuster and having fuel gas outlet and stack, one or more user points/facilities connected to the connective/ radiative heat exchanger to deplete heat and to obtain heat depleted medium, which is returned to the above mentioned heat exchangers in the system.
In a preferred manner, the heated medium is circulated through one or more user point/facilities by natural circulation without any pumps in the system. The user points being connected either in 'parallel' or in 'series' with respect to the circulating medium. The 'parallel' connection is shown in the figure for convenience sake and 'parallel and/or 'series' combination user facilities are not outside the scope of the invention.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS.
The invention will now be described with reference to the accompanying drawing where, Figure 1 shows the schematic representation of the proposed system 1. It is the normal known conventional fluidized bed combustor with or without "imbed heat exchanger (IBH) 2. There is provided a forced draft fan (FD) and the air is injected through a number of nozzles 'N' from below the support which support fluidized material such as sand. The hot air from the imbed heat exchanger flows upwards and is capable of combusting solid material fed from a feeder "F". The solid material is any agro based solid fuel. The air extracts heat from the bed and is capable of combusting any conventional/agro based solid fuels. Solid fuel is fed into the combustor by any known means such as a screw feeder "SF". The products of combustion (flue gas) then exchanges heat in a heat exchanger 3 which forms a close loop with IBH either connected in series or parallel with each other. The heated media is then circulated to the user point 4, either single or multi-user points, by natural circulation. The final flue gases are exited through an exhaust 5 assisted by fan FD
The "series" connection is shown in the figure for convenience sake and "series' and/or "parallel" connection are no) outside the scope of invention
In our evaluation tests, we have found a number of advantages of which the following are very important
1. Higher thermal efficiency.
2. Less pollution since sulphur capture in the bed is possible in fluidized bed.
3. Muiti-fuel capability.
We Claim:
(1) An improved Fluidized Bed Thermosyphon system comprising: a fluidised bed combustor (1)
capable of burning, a variety of both conventional and non-conventional solid fuels ,a solid fuel
feeder(S), a forced feed fan FD, to blow air from below the bed to effect fluidisation to provide
.primary heat exchange, the combustor being a normal bubbling bed or a conventional circulating
fluidised bed or a hybrid circulating fluidised bed and having optionally an in-bed heat exchanger
(2),a connective/radiative heat exchanger (3) utilizing common heat transfer medium like water,
dowtherm inside heat exchange tubes for recovering heat from the flue gases,
the connective/radiative heat exchanger being connected either in 'series' or in 'parallel' to combuster(1) and having fuel gas outlet (5) and stack (6), one or more user points/facilities (4,4) connected to the connective/ radiative heat exchanger(3) to deplete heat and to obtain heat depleted medium, which is returned to the above mentioned heat exchangers in the system.
(2) An improved fluidized bed thermosyphon system substantially as herein described with
reference to the accompanying drawings.
DATED THIS THE FIRST DAY OF JANUARY 2003.
( K.RAJAGOPALAN) Of Rajagopalan And Associates Agent for the Applicant.
