WO2016097878A1

WO2016097878A1 - Power producing preheaters for cement manufacture

Info

Publication number: WO2016097878A1
Application number: PCT/IB2015/050754
Authority: WO
Inventors: Amitesh PANDEY
Original assignee: Pandey Amitesh
Priority date: 2014-12-15
Filing date: 2015-02-01
Publication date: 2016-06-23

Abstract

The various embodiments herein disclose a wind power generation unit in a cement preheater comprising a preheater tower, a turbine and a wind duct. The turbine is fixed over the preheater tower. The turbine comprises a plurality of turbine blades connected with a turbine rotor. The wind duct houses the turbine rotor. The wind duct further comprises a plurality of inlet guide vanes and stators. An air entering into the wind duct faces a symmetrical parabolic volume shift from high volume to low volume. The volume shift further modifies after the turbine from low volume to high volume. The present invention increases a use of readily available wind power in cement production zones to provide a power supply during cement manufacturing procedures. This reduces the cost of power generation as it eradicate use of non-renewable power generation sources and also averts an effect on the environment.

Description

POWER PRODUCING PREHEATERS FOR CEMENT MANUFACTURE

BACKGROUND

Technical Field of Invention

[001] The embodiments herein generally relates to a power generation technology and particularly relates to an implementation of a wind power generation in a cement production line. The embodiments herein more particularly relates to an implementation of the wind power generation during a cement preheating to reduce an overall cost involved during a cement manufacturing.

Description of Related Art

[002] The cement industry relies one on few necessary base and those are coal, electricity, raw material (limestone, iron ore, laterite, flyash and gypsum) and transportation. The cost involved in each base decides an overall cost of the cement manufacturing. While a manufacturer cannot alter the cost margin involved in the coal, raw material and transportation, the electricity is only a viable option and route to decrease an overall cost in the cement production.

[003] One of the prior arts discloses a novel dry-process cement production line residual heat generation system, which includes a grate cooler, an AQC residual heat boiler, a cement rotary kiln, a cement rotary kiln head cover, a three-time wind blast pipe, a cement preheat machine, a cement pre-reduction furnace, a SP residual heat boiler, an air blower, a deaerator, and a condenser as well as a steam turbine generating set; wherein, the three-time blast pipe is positioned between the cement rotary kiln head cover and the cement prereduction furnace; while the cement rotary kiln head cover is communicated with the grog cooler. The utility model is characterized in that the pipeline of the three-time blast pipe is provided with a three-time wind residual heat boiler with a bypass wind tunnel, the working fluid entrance end of the three-time wind residual heat boiler is connected with the AQC residual heat boiler and the SP residual heat boiler through pipelines; while the working fluid entrance end is connected with the steam turbine generating unit and can fully dip out the process residual heat of the production line, so as to provide the overheat steam meeting the generation of the steam turbine generating set; and the cement ton grog generating volume is more than 40kwh, thus the utility model is easy to be implemented.

[004] However, the wind power generated in the intermediate processes of the cement manufacturing cannot be used optimally for power generation as the volume of wind is low and cannot be used to rotate high energy producing turbines. Also the wind power generated and used in the prior arts, fails to provide a velocity to rotate the turbine optimally failing in generation of required amount of power.

[005] In the view of foregoing, there is a need for an efficient renewable power generation technique to reduce an overall cost of cement manufacturing.

[006] The above mentioned shortcomings, disadvantages and problems are addressed herein, as detailed below.

SUMMARY OF THE INVENTION

[007] The primary object of the embodiments herein is to provide integrate a wind power generation mechanism with cement preheating.

[008] Another object of the embodiments herein is to enhance a power generated by the wind power generation mechanism.

[009] The various embodiments herein disclose a wind power generation unit in a cement preheater. The wind power generation unit comprises a preheater tower, a turbine and a wind duct. The preheater tower comprises a top slab having a height of 100 meters from the ground, width of 27.8 meters and breadth of 18.6 meters. The turbine is fixed over the preheater tower. The turbine comprises a plurality of turbine blades connected with a turbine rotor. The turbine rotor is at placed at a height of 130 meters and a diameter of 15 meters. The wind duct houses the turbine rotor and the plurality of turbine blades. The wind duct further comprises a plurality of inlet guide vanes and stators. The wind duct is at height 130 from the ground and have an inlet diameter and outlet diameter of 30 meters and 15 meters respectively. An air entering into the wind duct faces a symmetrical parabolic volume shift from high volume to low volume. The volume shift further modifies after the turbine, from low volume to high volume.

[0010] According to an embodiment herein, the power output ranges from 285.98- 1183.31 KW for an average wind speed ranging from 3-4.86 m/sec.

[0011] According to an embodiment herein, the plurality of inlet guide vanes and stators ensures an optimum angle of attack by an air flow to the turbine.

[0012] According to an embodiment herein, the wind duct increases an output power by 17 or higher times with respect to an atmospheric wind speed.

[0013] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS [0014] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:

[0015] FIG. 1 illustrates a diagram for preheater cyclone tower installed with wind power generation mechanism, according to one embodiment of the present invention.

[0016] FIG. 2 illustrates a block diagram of preheater cyclone tower, according to one embodiment of the present invention.

[0017] FIG. 3 illustrates a diagram of the wind duct, according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0018] In the following detailed description, a reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. The embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.

[0019] FIG. 1 illustrates a diagram for preheater cyclone tower installed with wind power generation mechanism, according to an embodiment herein. With respect to FIG. 1, the wind power generation unit comprises a preheater tower 101, a turbine and a wind duct

104. The preheater tower 101 comprises a top slab having a height of 100 meters from the ground, width of 27.8 meters and breadth of 18.6 meters. The turbine is fixed over the preheater tower 101. The turbine comprises a plurality of turbine blades 102 connected with a turbine rotor 103. The turbine rotor is at placed at a height of 130 meters and a diameter of 15 meters. The wind duct 104 houses the turbine rotor 103 and the plurality of turbine blade 102. The wind duct 104 further comprises a plurality of inlet guide vanes and stators. The wind duct 104 is at height 130 from the ground and have an inlet diameter and outlet diameter of 30 meters and 15 meters respectively. An air entering into the wind duct 104 faces a symmetrical parabolic volume shift from high volume to low volume. The volume shift further modifies after the turbine, from low volume to high volume.

[0020] According to an embodiment herein, the wind velocity increases with height or altitude from ground, hence it is the function of height from ground. A turbine swept area or a rotor diameter is a design parameter and is selected as per a preheater design criterion and site conditions. An air density has very less effect on wind turbine output while an augmentation provided in the wind duct is also a design parameter. Thus, the favorable conditions for better output from wind turbines are an obstacle free area for wind flow, high altitude, turbulence free wind, optimum augmentation (ducting) and high average wind speed. A cement plant has various properties favoring an installation of a wind power generation unit which are:

a) Distant from urban area.

b) A preheater cyclone tower of R-C-C (Reinforced Cement Concrete), with general height in range of (80-130) meter ( good altitude for ducted turbine installation) c) Necessary supporting structure to install a ducted wind turbine and support for the ducting for improved performance of wind turbine.

[0021] According to an embodiment herein, the structure of such a wind turbine is installed on preheater top i.e. at (80-130 meter height above from ground with or without duct augmentation). A ducted turbine is installed on the top of the preheater tower to keep the turbine rotor' s size minimum. [0022] According to an embodiment herein, the wind power generation unit utilizes l/7th law of wind velocity. The main factor for wind turbine output is wind velocity which increases with height from the ground level. In cement manufacturing process, a reinforced concrete cement structure of sufficient strength and height (material composition of R.C.C is M20/ M30) and (80-130) meter height is available which is favorable to tap a high wind velocity. This type of preheater tower is well enough in strength to carry the load of ducted wind turbines as through augmentation we have choice to compromise with rotor size. One of the most important advantage of using this preheater tower for augmented wind turbine installation, is to get a free i.e. obstacle free good average wind velocity due to its high altitude from ground. At this height (80-130 meter) the average wind velocity is better than at 10 meter height (due to wind velocity l/7th law).Due to l/7th law of wind velocity the average wind velocity on preheater top is increased as:-

V V₂ = (H^H,)¹^

[0023] Where V_x is the wind velocity at P.H top height and V₂ is the general average wind velocity given by either direct measuring the wind velocity or at 10 meter height from ground. Similarly H_x and H₂ are the preheater top rotor's hub height and at 10 meter height. In any case of cement plant using 100 meter high, R.C.C structured preheater tower, the annual average wind speed is 4 m/sec at 10 meter height, then annual average wind velocity on preheater tower top is as per formulae:-

VJV₂ = (H^H,)¹^

Or, V₁I = (100/10) 1/7 = (10)1/7 = (10)0.142857 = 1.389495

Or, ₁=Preheater tower top wind velocity = 4x1.389495 = 5.558 m/sec.

[0024] Hence the 4 m/sec. wind velocity is converted into 5.558 m/sec. wind velocity. This magnification in wind velocity is very important as it reduces the size of the rotor and hence total cost and load on preheater tower too. [0025] Similarly the power density amplification is calculated as:-

[0026] According to an embodiment herein, the ducted wind turbine increases the wind power output nearly 17 times. The ducted turbine works on the principle of equation of continuity i.e.

A_XV_X = A₂V₂

[0027] Where, i4₁and A₂ are area of duct at any two places while V_x and V₂ are the velocities of wind at these two points respectively. By using the continuity principle, a desired wind speed is achieved at the turbine's rotor area which in turn reduces the rotor's diameter. Since the ducts of ducted wind turbines use the guide blades to guide the outside wind to rotor's directions, hence change direction of wind does not cause any effect on the turbine. The inlet guide vanes and stators have been incorporated into the design of ducted wind turbine to ensure that air flow is offered to the turbine at an optimum angle of attack.

[0028] According to an embodiment herein, the inlet guide vanes and stators act to direct an air field in a particular direction. In the areas of low pressure turbulence, the inlet guide vanes and stators precisely alters the flow to components and increases an efficiency.

[0029] According to an embodiment herein, the turbine further comprises a variable inlet guide vane's (VIGV'S) which is adjusted to apply a favourable spin to the most air flow thereby offering the stream at the most optimum angle of attack for the particular wind speed. The VIGV'S is also used in high winds where the vanes are turned, as this alleviates the need for a variable pitch turbine blade and reduces the complexity of the design.

[0030] FIG. 2 illustrates a block diagram of preheater cyclone tower, according to an embodiment herein. With respect to FIG. 2, the typical parameters of preheater cyclone tower are:

1. Height of top slab (roof) of preheater tower from ground = 100 mater 2. Width of preheater tower = 27.8 meter

3. Breadth of preheater tower = 18.6 meter

[0031] FIG. 3 illustrates a diagram of the wind duct, according to an embodiment herein. With respect to FIG. 3, the parameters to design the wind duct and turbine are:

4. Average wind speed (minimum required / obtained) = 3 m/sec. = V₁₀

5. Overall height of wind turbine rotor = (100+30) = 130 meter (30 meter is hub height from tower top slab, assumed on the basis of ease of fabrication for case study only)

6. Dimensions of duct prepared = dia. = dl=15 meter, d2 = 30 meter (assumed on the basis of ease in fabrication, for case study only)

7. Diameter of rotor = 15 meter (least dia. of venturi of duct)

These dimensions are decided and on the basis of ease of fabrication at this height of 130 meter and these are assumed data for a typical case study and can be vary as per site and design.

8. Average wind density \ = 1.24 kg/m³

[0032] According to an embodiment herein, a case study over the design parameters of the wind power generation unit and results produced by them are disclosed as follows: • First of all using 1/7^ώ law of wind velocity at high altitudes:-

We have: - Vio = 3 m/sec.

Vi3o i.e. At rotor's height =? hio = 10 meter hi3o = 130 meter Using l/7^ffi law:

Or Vi3o = 3 x (13)7 = 3 x 1.442 Hence, V130 = 4.326 m/sec

Hence wind speed at rotor's height = V130 = 4.326 m/sec.

• Now using equation of continuity for duct as:- Ai Vi = A₂ V₂ Or A1V1 = A₂V₂

Here,

Ai =— di², di= 30 meter

Vi = Vi3o = 4.326 m/sec

A₂ = — d₂ ², d₂ = 15 meter

4

V₂ = not known Hence = A1V1 = A₂V₂ Or

Ai x Vi3o = A₂ x V₂ Or

— di x Vi3o = — d₂ x V₂

4 4

Or di² x Vi3o = d₂ ² x V₂ (30)² x 4.326 = (15)² x V₂ Or

30Z30Z4.326 _{= 4 326X 2X 2}

15X15

= 4.326 x 4 = 17.304

.·. V₂ = 17.304 m/sc = wind speed at rotor's hub

Wind speed at rotor's venturi = 17.304 m/sc

[0033] Now the maximum power obtained from these dimension's is calculated, taking considerations of Betz limit of maximum power output as 16/27 and all efficiencies including mechanical, electrical and aerodynamic efficiency as overall efficiency:-

C_P = 0.518827 « 0.50 Hence maximum power obtained is

Pmax = ^~ X ^.air X Arotor X ^rotor X Cp = - x 1.25 x -x (15)² x (17.304)³ x 0.50

2 4

= 285983.4 W max— 285.983KW

[0034] This is the power obtained when considering the annual average wind speed as 3 m/sec. which is the minimum necessary wind speed to install wind turbine at any location. Now in the same way, the minimum and maximum wind power at the above two peak locations is calculated (with same dimensions of the turbine):-

[0035] For minimum speed of 3.334 m/sec. ;-

Ui30 = Uio x 1.442 = 3.334 x 1.442 Ui30 = 4.81 m/sec AiVi = A₂V₂ Or

Or

(30)² x 4.81 = (15)² x V₂ V₂ = 4x4.81 V₂ =19.24 m/sec

= -x 1.25 x— x(15)²x(19.24)³x0.50

2 4

=0.5 x 1.25 x— xl5 x 15 x 19.24 x 19.24 x 19.24 x 0.50

4

= 393112.994 W max— 393.112 KW

With minimum wind speed of 3.334 m/sec

[0036] For maximum wind speed of 4.816 m/sec; -

Ui30= 1.442 xUio= 1.442 x Ui30 = 4.816 x 1.442 Ui30 = 6.95 m/sec Now At rotor's venturi- AiVi = A₂V₂ Or

— di² x Vi3o =— d₂ ² x V₂

4 4

Or, (30)2x6.95=(15)2xV2 V₂ = 6.95 x 4 Vrotor = 27.78 m/sec

Pmax = ~ X

X Cp

= - x l.25 x - x (15)2 x (27.78)3 x 0.5

2 4

= - x 1.25 x— x 15 x 15 x 27.78 x 27.78 x27.78 x 0.5

2 4

= 1183311.052034 W

Pmax = 1183.32 KW with maximum wind speed of 4.816 m/sec [0037] All these power outputs are obtained considering the same dimension parameters like-

• Rotor's height = 130 meter (100 meter of cement preheater tower plus 30 meter)

• Wind Density = 1.25 kg/m3

• Duct's inlet dia. = 30 meter

• Duct's venutri dia. = 15 meter

• Rotor's dia. = 15 meter

• Coefficient of power transformation (generation) = 0.50. [0038] Variation in output data;-

Nearly 10 % of variation in output may be there in all calculations, e.g. :-

1. Wind Density: - As the wind density is also dependent on ambient temperature and since temperature of 10 meter's wind height is different from 130 meter's height, so there is a change in wind density at 130 meter height. This charge is not considered in the calculations as the difference in the two densities is so less that it can be neglect from calculations. 353.12

Air density temp \ (kg/m² ^')

273.15 + Γ

Air density V/s height 1.194 x 10-4 kg/m³

2. Rotor's Dia.— During all calculations, the rotor' s diameter is takes as 15 meter which is also the dia. of duct at the venturi. But there is a marginal clearance between rotor's blade and duct. Also the diameter of hub is not considered which is reducing the effective rotor's diameter and hence the overall swept area of rotor, hence reducing the power generation too. But this reduction is also very negligible and hence not considered in all calculation.

3. Seasonal Variation in Wind Speed: - Due to seasonal variation in wind speed the turbines output is effected a little bit, and hence the power output obtained is fluctuating in nature. Though it is controlled in a large extent by using ducted wind turbine, but still a user should be ready for small fluctuations in output power.

4. Technological Development:- This case study is done for only a simple case. But the rapid changes in technologies encourage the installation of 3 P.H. in cement plants. These favourable techniques or innovations can be like- innovation of very light carbon fibre material for rotor or for duct or for tower etc, will be helpful to increase the output power with low size turbine. Similarly use of very low speed generators will reduce the rotors r.p.m. and hence indirectly the size of venturi and hence will reduce the overall size and hence the installation and maintenance cost too.

[0039] The wind power generation unit increases a use of readily available wind power in cement production zones to provide a power supply during cement manufacturing procedures. This reduces the cost of power generation as it eradicate use of non-renewable power generation sources and also averts an effect on the environment. Further since the wind power generation unit is incorporating significant changes in basic structure of the preheater tower, so further reduce the cost of manufacturing. Also the utilization of coal which is main ingredient in conventional cement manufacturing and power generation, is diverted completely toward cement manufacturing. Thus loss of coal for power generation is reduced.

[0040] It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the claims.

Claims

CLAIMS: I claim:

1. A wind power generation unit in a cement preheater, wherein the wind power generation unit comprises:

a preheater tower, wherein the preheater tower comprises a top slab having a height of

100 meters from the ground, width of 27.8 meters and breadth of 18.6 meters;

a turbine, wherein the turbine is fixed over the preheater tower, wherein the turbine comprises a plurality of turbine blades connected with a turbine rotor, wherein the turbine rotor is at placed at a height of 130 meters and a diameter of 15 meters;

a wind duct, wherein the wind duct houses the turbine rotor and the plurality of turbine blades, wherein the wind duct further comprises a plurality of inlet guide vanes and stators, wherein the wind duct is at height 130 from the ground and have an inlet diameter and outlet diameter of 30 meters and 15 meters respectively;

wherein, an air entering into the wind duct faces a symmetrical parabolic volume shift from high volume to low volume, wherein the volume shift further modifies after the turbine from low volume to high volume.

2. The unit according to claim 1, wherein the power output ranges from 285.98- 1183.31 KW for an average wind speed ranging from 3-4.86 m/sec.

3. The unit according to claim 1, wherein the plurality of inlet guide vanes and stators ensures an optimum angle of attack by an air flow to the turbine.

4. The unit according to claim 1, wherein the wind duct increases an output power by 17 or higher times with respect to an atmospheric wind speed.