|Title of Invention||
AN ENERGY CONVERSION UNIT & METHOD FOR CONVERTING HIDDEN ENERGY FROM THE TRANSITIONAL PHASE EXISTING DURING THE TRANSFER OF HEAT ENERGY FROM GASEOUS MEDIUM TO ANY SYSTEM IN CONTACT
|Abstract||This report discusses about an innovative way of generating additional power from any combustible fuel. The plant proposed for additional power generation is titled PHE plant, where PHE stands for "Power from Hidden Energy". It is so named as the plant can tap out additional energy from the transitional phase that exists during the transfer of heat energy from gaseous combustion product to any system in contact. From a given mass of gaseous combustion product at high temperature but at atmospheric pressure, we generally tap out only the heat energy stored But the said gaseous mass is having the potential for one another source of energy also, which is not properly availed in conventional plants. The proposed system is an answer to this. While tapping out heat energy from given mass of gas enclosed in a closed vessel that is at high temperature and at atmospheric pressure, there will be a pressure drop inside the vessel as per Gay lusac law. This pressure drop with respect to the surrounding will be a source for power in addition to the heat energy that is tapped out in conventional plants.|
The invention relates to an energy conversion unit for converting hidden energy during combustion of any kind of fuel including waste materials.
An innovative way of generating electricity from solid fuel is by tapping energy from a transitional phase in the process of combustion. During combustion of fuel material, large volume of flame, which is gas at high temperature, is produced. The flame will have high temperature initially, which upon transferring the heat energy to a condensing system in contact, drops the temperature. Simultaneously with the temperature drop a proportionate drop in a pressure of the gas takes place. This temperature drop and the associated pressure drop of the gas during transition by losing its heat energy is indispensably a transitional phase in any thermal process of this kind. The pressure drop will result in a differential pressure with respect to outside atmosphere. Differential pressure always has the potential for power generation. The potential of this transitional phase is left unnoticed so far. Hence the energy obtained from this phase is referred to as " Hidden energy", through out the specification. Exploiting this transitional phase for power generation will not disturb the efficiency of the conventional heat transfer process. This energy tapped out from the transitional phase is an additional power or bonus to the power yield obtained through the conventional method.
There are two options available in the above-referred method of power generation. In the first method the apparatus may reap out the hidden energy alone. In the second method in addition to the power yield from the conventional power generation unit, an approximately equal quantum of power can
be obtained through the hidden energy as a supplementary lot. Thus hidden energy as an appended unit to conventional power generation plant is enabled. It is interesting to note that the hidden energy can yield approximately equal to or even higher than what conventional plants yield from a given quantify of fuel.
A major source of power generation is possible from combustible materials such as municipal waste. Disposal of municipal waste is an inevitable commitment to the Government in view of public health and social reasons.
Many countries have set up plants for generating electricity from municipal waste. And the process followed is using waste as fuel for steam boiler to generate steam. This steam is used to run steam turbine for producing electricity. Boiler and turbine which form the twin heart of these types of units, are sophisticated and need very high capital cost, precise erection and alignment, followed by skilled operation and frequent expensive maintenance. In addition, the boiler calls for stringent safety standards formulated by Boiler Regulatory Boards. Also such a unit requires a large resource of treated water, which requires water treatment plant, an additional investment in terms of capital cost, maintenance cost, etc
The energy conversion unit for converting hidden energy according to the invention extracts additional energy, which no plant has exploited so far. The energy conversion unit according to the invention is capable of producing power in addition to the power that is generated from a conventional unit. The additional power may be equal to or even higher
Than what is produced in a conventional plant from a source of unit quantity. So the power produced in an energy conversion unit according to the invention may be approximately twice than in a conventional plant. The energy conversion unit according to the invention requires low capital* cost; minimum maintenance and the unit can be run with minimum number of semiskilled operators either. In conventional units, heat energy of the fuel is transferred to water for generating steam. During the heat transfer there will be some energy loss, which is inevitable. Feed water for boiler is available at room temperature. The portion of the energy required to raise the water temperature from room temperature to boiling point temperature is termed as sensible heating energy required. This heat energy may be recovered using boiler feed water heater at an increased cost.
An alternative is to use a medium, which eludes the above said disadvantages connected with using water as medium. The energy conversion unit according to the invention enables electrical energy production from low calorific value fuel such as municipal waste, optionally along with any other fuel. Instead of using the municipal refuse directly, it can be dumped underground, which will liberate biogas. The biogas can also be used as source of fuel. When these fuels are burnt, a large volume of flame is produced. This flame itself can be used as a working medium. If this flame is collected in an enclosure and allowed to cool there will be sudden temperature drop, which will reflect in a proportionate pressure drop inside the enclosure. This pressure drop sets up a differential pressure with respect to atmosphere, which can be used to generate power. The main advantage here is, power is generated from an energy source in its very primitive form,
and so the thermal efficiency will be higher compared to other systems. Since the system according to the invention is not using any secondary medium like water, as in conventional plants, there is no heat transfer loss, no large-scale water consumption. Therefore there is no need for treatment plant and associated capital and maintenance cost. Due to these reasons unit according to the invention is cost effective.
The principle of working of the energy conversion unit according to the invention is follows. Any gas medium at high temperature expands to occupy more volume, similarly at lower temperature contracts to occupy lesser volume. So when flame from a burning object is collected in a closed container and allowed to cool, the pressure inside the container will come down sharply. The differential pressure developed between the container inside and outside atmosphere can be used to drive a prime mover to convert the heat energy into electrical energy.
It may be noted that when combustion of fuel is carried out to heat a system or to heat water to produce steam as in the case of boiler, a transition phase exists. In this transition phase, the phenomena of expansion and contraction of heating medium takes place. But so far it is not tapped using suitable device to exploit this hidden energy, which is dissipated unnoticed. The energy conversion unit according to the invention provides means to tap this hidden energy.
With reference to the accompanied drawing in the provisional specification:
Figure 1 shows an exploded view of the energy conversion unit according to the invention.
Figure 2 shows an isometric view of part of the energy conversion unit shown in figure 1.
Figure 3 shows a cross sectional view of the energy conversion unit shown in figure 1.
Figure 4 shows a partial cross sectional view of the impeller housing
Figure 3 shows the side disk with projections to grip the fixed vanes.
The energy conversion unit according to the invention mainly consists of the following components.
1. Combustion chamber (1)
2. Impeller housing (9)
3. Impeller (2)
4. Cooling Jacket (3)
The Combustion chamber (1) is an enclosure closed on all side except at the top. The Combustion chamber (1) is provided with a top tray (13) and a bottom tray (14). The top tray is for loading solid waste combustion materials such as the solid waste and the bottom tray (14) is to collect ash generated from the burnt fuel. The inside surface of the chamber (1) is lined with refractory brick and the outside surface of the chamber is covered with good insulating material, to prevent any heat loss. The sidewalls of the
chamber (1) above the bottom tray are having sufficient grill openings to supply fresh air into, the chamber for combustion. The topside opening of the combustion chamber (1) is provided with fine wire mesh, to filter the flying ash generated during combustion, from entering into the Impeller housing (9).
The impeller housing (9) comprises a long cylindrical shell closed at both ends. The shell is provided with three lengthwise opening around its circumference. The opening at the bottom most location of this shell is connected to the combustion chamber (1), so that the combustion product that rises up will enter into the housing (9). The second opening is connected to the suction duct (4). At least one turbine is mounted to an exhaust duct (5). The mouth of this duct is open to atmosphere.
Modern axial flow wind turbines are usually built with three no. of blades with aerofoil cross section. Power developed is proportional to the projected area of the blades against wind flow direction. However, if this projected area is increased further by increasing the number of vanes, it may not develop the expected increase in power out put. One of the reasons for this is that with the increase in the number of vanes are increased; it proportionately increases the resistance for the air to flow through the turbine. Due to this increased resistance to the airflow, the flowing air stream would by pass the turbine. But the turbine (6) used in the energy conversion unit according to the invention used in can be provided with optimum number of blades as in the case of steam turbine. The reason is, the turbine mounted at the mouth of conduit, is open to atmosphere at one end and to the
Impeller chamber at the other end, which is maintained at negative pressure. Due to this imbalance of pressure, air will rush from outside to inside. During this process, the air has no other scope but to pass through the turbine, driving it.
Impeller assembly (2) is mounted co-axially inside the Impeller housing (9). The impeller consists of central hollow hub (23), which is having plurality of radial fixed vanes (10). The fixed vanes (10) are hollow and cooling water can be passed though the impeller hub, to cool the high temperature gases coming in contact with these fixed vanes (10). While the root end of the vanes are fixed to the impeller hub (23), the other end is free making close clearance with the inside wall of the Impeller housing (9). The free end is provided with flexible unidirectional and self-locking seal (20). The two sides of the Impeller housing (9) are closed with side discs (7). The side discs (7) are having slotted projections (22). The inside of the slot surfaces are provided with gasket lining. The side ends of the fixed vanes (10) are inserted into the slots (22). The gasket will compress and hold the fixed vanes (10) airtight. Any two adjacent fixed vanes (10) along with the housing (9) inside and the corresponding portion of side disks (7) form a compartment. Each said compartment is provided with circular stiffener rods (12), which are arc shaped. In each compartment one floating vane (11) is provided. The stiffener rod (12) pierces though the floating vane (11), allowing the floating vane (11) to slide over the rods from one end of the compartment to the other end. In order to have smoother movement of the floating vane (11), hinged joint can be introduced. That is floating vane (11) at its root end may be provided with two or more sleeves, that can revolve around the central hub (13) that acts as the
central pin in the hinged joint. This is analogous to the swing of the door with respect to the door hinges. The dimension of the floating vane (11) is so designed that the all four edges of the vane (11) make very close clearance with adjacent surfaces. The edges of the floating vanes (11) are also provided with unidirectional seal.
The central portion of the Impeller assembly is called the impeller Hub (13). The impeller assembly is provided with a central solid shaft (18) positioned concentrically inside a hollow shaft. There will be sufficient annular gap (17) is provided between the impeller shaft (18) and impe 11 er hub (18). This annular gap (17) is open to the hollow portion (16) of the fixed vane (10). Preferably heat tubes may be embedded to the walls of the fixed vanes (10) and inside surfaces of the impeller housing (9) to increase the rate of heat transfer from the entrapped gas to the coolant available in the cooling jacket (3) and in the hollow space (16) of the fixed vanes (10). The central solid impeller shaft (18) is supported over Plummer block arrangement. The impeller assembly is mounted on the shaft. By rotating the shaft, the impeller assembly can be revolved at required rpm.
Cooling jacket (3) is constructed surrounding the top portion of the Impeller housing (9) and wherever space is available. The cooling jacket (9) is filled with water. This water in the cooling jacket (9) will remove the heat from the hot gas enclosed inside the impeller compartments. Temperature rise of the cooling medium due to the heat energy absorbed can be used as a heat source for any other process. For instance this heat can be used to heat the feed water of boiler, to obtain increased thermal efficiency of the unit. In order to use this
rejected heat more efficiently, heat tubes can also be embedded on the fixed vane (10) and on impeller-housing walls. As a result of this the rate of heat transfer will become rapid, resulting in increased the efficiency of the unit. Furthermore the heat loss will also be reduced.
The operation of the energy conversion unit according to the invention is described below. Initially the combustion chamber is loaded with solid waste fuel and ignited. The flame billows up and fills the compartment in position Pi. As the impeller unit rotates continuously in anti clockwise direction, the compartment above combustion chamber in position PI moves to the next position. Due to this movement, the flame collected in this compartment will be transported along with it. The impeller keeps rotating and eventually each compartment starts moving from place to place. Simultaneously the flame contained in the chamber starts cooling down. This cooling rate will be very high, as the heat capacity of the flame is very low. The heat tubes (19) embedded on the impeller housing (9) and on the fixed vanes (10) accelerates rate of cooling. As the gas temperature inside the chamber drops down, the pressure of the gas medium inside also comes down sharply. Hence a difference in pressure is developed between the chamber inside and the outside atmosphere. When the compartment comes to position P2, the floating vane due to gravity will slide down towards the leading fixed vane in the front. When the chamber comes to position P3, the compartment inside is exposed to outside atmosphere through the suction duct (4). Due to the negative pressure prevailing inside the compartment, air from outside rushes inside driving the turbine mounted at the mouth of the
suction duct, which is used to generate electricity when coupled to turbo generator.
Once the outside air rushes inside the chamber, the pressure in the chamber attains atmospheric pressure. With further revolution of the impeller assembly (2), the chamber will move away from the suction duct (4) and comes in contact with the exhaust duct (5). The floating vane (11) at position P4 gets aligned with the fixed vane (10) in the front. Additional mechanism may also be built into to the system to ensure the floating vane (11) to get aligned with the fixed vane (10) quickly. When the floating vane comes to position "X", in line with the wall of the exhaust duct (5) it is held in position by a spring-loaded stopper. The spring tension is so chosen, that a predetermined additional force is required to overcome the spring tension and move the floating vane (11) ahead. With the floating vane (11) held by a stopper, and the impeller rotating, the fixed vane (10) in the front starts departing the floating vane (11), due to which the zone in the front side of the floating vane (11) will experience suction resulting in charging the chamber with burning flame billowing up from the bottom. Simultaneously the fixed vane (10) at the back side of the floating vane (11) will move closer and closer to the floating vane (11), due to which the cooled air along with atmospheric air collected during previous stages gets expelled outside through the exhaust duct (5). Once the fixed vane (10) in the back comes in line with the floating vane (11), the fixed vane (10) will impart sufficient force to overcome spring tension of the stopper and move away the floating vane (11) from it's position. Thus one complete cycle of a chamber is completed.
The solid fuel, which may be waste material, can be completely burnt out in unit when the operation starts and combustion can be stopped instantaneously when feeding of fuel is stopped. Therefore it is easy to stop the operation without the banked fire. The energy conversion unit according to the invention is suitable for power generation from solid fuel such as collected municipal waste.
POLLUTION CONTROLIN THE CONTEXT OF THIS UNIT:
Municipal refuse usually contains a wide range of materials, which on combustion will liberate many kind of health hazardous fumes. Therefore pollution control is an important factor to be considered, in the combustion of municipal waste. There are many modern established developments available to control this environmental pollution like,
Flue Gas Scrubbers
Particulate matter control
Incineration: Incineration technology is the controlled combustion of waste with the recovery of heat to produce steams that in turn produces power through steam turbines.
Flue Gas Scrubbers: These are equipments to wash away the flue gas before discharging it into the atmosphere.
Particulate matter control: Particulate matter control in the combustion of fossil fuels is primarily accomplished with electrostatic precipitators (ESPs).
Municipal waste generally contains paper, food waste, textile, wood pieces, leather, and rubber, plastic and miscellaneous items in various proportions.
Table-A below is the survey report furnished by an agency, on the proportion (average value) of one Kg. of municipal waste and the corresponding energy potential. Multiplying each proportion with its corresponding calorific value, it is learnt that one tone of municipal waste contains an energy potential of 10,500MJ (rounded).
From the table-A, it is known that the calorific value of a Kg. of municipal waste is lOMJ (approx). Therefore the energy conversion unit according to the invention consuming a Kg. of waste per second can ideally develop a power output of 10 MW. For this power output the energy conversion unit according to the invention will need (3600*24 ‘L 85000) 85 Tones of feed per day.
It is a fact that standard atmospheric air surging into a
chamber of Im volume, in one second, where the vessel is
maintained at absolute vacuum can develop look of power.
These two inputs are used in arriving the theoretical power
output of the energy conversion unit according to the
of a given dimension
Following important assumptions are made during the estimation of performance of the energy conversion unit according to the invention.
It is assumed that Municipal waste on combustion produces flame at 800’C. This combustion product if collected in an enclosed chamber, will be at 800’C initially. On cooling, the temperature will drop down to 50*’0. The pressure drop corresponding to this temperature drop will be 0.7 Kg./Cm’.
Means the absolute pressure prevailing inside the chamber will be 0.3 Kg./Cm’(abs.) after loosing the heat energy.
Assume the energy conversion unit according to the invention with 12no. of impeller chambers, where each chamber of the impeller assembly is having a net volume of Im . If the chamber is filled up completely with flame, after loosing the heat energy the chamber inside will be at 0.3 Kg/Cm’(abs.). Atmospheric air surging into the chamber in one second can develop ideally a power output equal to 70KW. If the impeller revolves at 15rpm, in the energy conversion unit according to the invention, three chambers would have been filled up with ambient air for each second. The corresponding theoretical power output will be 210KW.
Below estimation is done for both, the energy conversion unit according to the invention of Independent type as well as for Dual power type where the unit is an attachment of the conventional plants, on the basis of above assumptions. Additionally for estimation, the thermal efficiency of independent type plant is assumed to be around 40 to 50%, while for Dual power type it is assumed to be around 80%.
With the above assumptions, it can be claimed that from a energy conversion unit according to the invention whose impeller diameter is roughly 4 mtr, length equal to 10 mtr. and having 6 no. of impeller fixed vanes, an electrical output that is approximately equal to a minimum of 1 MW to a maximum of 1.75MW can be generated if the impeller rotates at ISrpm.For this power generation approximately 700 Kgs. of solid municipal waste is required per hour. Which means 15 to 20 Tons of solid waste fuel is required per day to
run the plant with this power output. To cater a small town or a village few number of this size plants may be sufficient.
Similarly, a small energy conversion unit according to the invention (of Independent type) whose impeller diameter is roughly equal to 0.5 mtr. and length equal to 1 mtr, that revolves at around 15rpm, can generate an electrical power output that is approximately equal to a minimum of 1.25KW to a maximum of 2.5KW. For this power yielding, approximately 0.75Kg. of municipal waste is required per hour. Which means around 20 to 25Kgs. of solid waste fuel is required per day to run the plant with this power output. This power output is sufficient for serving a few numbers of houses in except during peak load demand. Therefore this kind of plants commissioned in civil apartments, in addition to generating electrical power output, persuades a proper way of waste disposal there by keeping the environment clean and help the Government by sharing its commitment of power generation.
Municipal solid waste is generated in the order of 1000s of tones per day in cities / towns. Maximum proportions of the waste generated are of low calorific value grade. Low calorific fuel usually has some inherent demerits in using as a fuel for power generation using conventional methods. But an energy conversion unit according to the invention can run efficiently using low calorific value fuel.
Indian Scenario: Surveys conducted by agencies claim that, generally municipal solid waste is generated at the rate of 0.4Kg per person per day. There are several options available
to convert solid waste to energy some of the prominent technologies available are
b. Sanitary Landfill
d. Anaerobic Digestion
In each of these technologies the solid waste is converted into some state that is suitable for combustion. Energy conversion unit according to the invention can generate power whatever be the state of the combustion medium.
In Cheney alone municipal waste generated is threateningly high in the order of 1400 tones per day. This source is a viable potential to be exploited of. This quantum is sufficient for a power yield of approximately 75 MW to 125 MW, which can share a reasonable portion of the electrical requirement of the city. Accumulation of large volume of waste for a long time is dangerous to the environment. The best way to solve the problem is to reduce the volume by burning, by which even 90% volume reduction and 75% weight reduction, is achieved. As in the case of any power generation method the municipal refuse is burnt in the energy conversion unit according to the invention. Thus the plant assures for easy disposal of the municipal refuse generated.
Global Scenario: In developed countries the rate of waste generated by an individual is used to be higher. For instance, statistical report says in a highly developed society like Great Britain or U.S.A., solid waste is produced at the rate of about 1 tone per person per year. The report also says each
year UK produces 28 million tones of solid domestic waste plus similar amount of industrial waste.
POTENTIAL OF PHE PLANT
In petroleum refineries a large volume of natural gas is formed as a bi-product, which is ignited at the mouth of the stack. The potential of this combustion product is not utilized, as it is difficult to set up conventional power generating plant at that location in view of its size and complexity. But an energy conversion unit according to the invention in view of its compactness can be installed for power generation.
It is practical to construct an energy conversion unit according to the invention of any capacity, as per the requirement, ranging from as mall as, what is required for domestic application to large enough to meet the municipal/ town requirement
The energy conversion unit according to the invention of a given size can develop a range of power output. If the heat removal rate form the gas entrapped in the impeller chamber is increased by embedding heat tubes (19) to the impeller housing (9), the rate of revolution of the impeller can be increased. If the rpm of the impeller assembly is increased, the power output will be increased proportionately
MERITS OF THE ENERGY CONVERSION UNIT ACCORDING TO INVENTION:
In general using municipal waste as a source for energy production serves dual benefits, i.e. in one hand the wastes are segregated, disposed off and on the other hand the much-craved electricity is obtained.
The energy conversion unit according to the invention can be started and stopped immediately, unlike conventional plants, i.e. a small plant of this kind can generate a proportionate quantum of power even from a source, say a piece of paper of size as small as 10cm x 10cm or even smaller. While the conventional plants need minimum time period to achieve phase change from water to steam to effect power generation. Additionally the plant needs time, to raise the water temperature from room temperature to boiling temperature, corresponding to the local pressure prevailing above the water surface. This kind of delay will be reflected in the form of loss of thermal efficiency.
AUGMENTATION OF THE UNIT:
11.1 With the plant running, the coolant water temperature in the cooling jacket will rise rapidly, which can be used as a heat source for another conventional power production plant or any other equipment or any other industrial processes that uses heat energy as input. This approach will add upon to the efficiency of the plant. Again as the ignition of the fuel is carried out in an enclosed space, processing of the flue gas produced by any one means as discussed earlier is achievable, whereby air pollution can be contained.
The energy conversion unit according to the invention can be set up at a low capital cost, and as we have seen the unit extracts additional energy, so will offer high efficiency. The plant requires only minimum number of semiskilled operators because of low maintenance, and requires less water source. The energy conversion unit according to the invention can be commissioned and run effectively even in rural places. So if a few numbers of such plants are commissioned in villages/ cities/ towns, the area can be made self-reliant from the view of electric power requirement. As the plant can be run with the municipal waste generated, the plant in addition to yielding electric power, offers an effective way to dispose off the waste generated.
1. An energy conversion unit for converting the hidden energy during combustion of
any kind of fuel including waste material consist of a combustion chamber (1), with
top tray (13) and bottom tray (14), Impeller assembly having a central solid shaft (18)
and optimum number of fixed radial vanes (10), reinforced by arc shaped rods (12)
and floating vanes (11) and the Impeller assembly (2) is enclosed inside a n Impeller
housing (9) which is surrounded by cooling jacket (3)/ cooling coils and the impeller
housing is connected to Suction duct (4) and an exhaust duct (5), where the suction
duct is having a turbo generator (6) mounted at its mouth and the impeller housing on
both ends have side disks (7),
2. An energy conversion imit for converting the hidden energy during combustion of any kind of ftiel including waste material is having fixed vanes (10) whose inside is hollow and provided with heat tubes and additionally the fixed vanes are having lip seal arrangement at its fire end.
3. An energy conversion unit for converting the hidden energy during combustion of any kind of fuel including waste material consists of impeller housing with heat tubes embedded.
4. An energy conversion imit for converting the hidden energy during combustion of
any kind of fiiel including waste material consists of floating vanes having hinge
arrangement at its bottom end with the central solid shaft as the central pin of the
hinge for smoother movement.
5. An energy conversion unit for converting the hidden energy during combustion of any kind of fiiel including waste material consists of a spring-loaded stopper at the bottom in position-1 (Figure - 3).
6. An energy conversion vomit for converting the hidden energy during combustion of any kind of fuel including waste material produces power fiow the transitional phase that exists in any combustion process.
7. An energy conversion unit for converting the hidden energy during combustion of
any kind of fuel including waste material produce power from any kind of fiiel
including waste material.
8. An energy conversion unit for converting the hidden energy during combustion of
any kind of fiiel including waste material with modifications can be added to
conventional thermal power plants using any kind of fiiel including waste material.
|Indian Patent Application Number||918/MAS/2002|
|PG Journal Number||50/2007|
|Date of Filing||10-Dec-2002|
|Name of Patentee||SHRI. ARUMUGAM KRISHNAN KARTHI|
|Applicant Address||107,CENTRAL AVENUE,DAE TOWNSHIP,KALPAKKAM,KANCHIPURAM DISTRICT.|
|PCT International Classification Number||F02B 43/08|
|PCT International Application Number||N/A|
|PCT International Filing date|