City University of New York (CUNY)
CUNY Academic Works
Master's Theses
City College of New York
2012
Exploration of the Endothermic and Exothermic
Reactions of Calcium Oxide and Magnesium
Oxide and Design of a Vessel for a
Thermochemical Heat Storage System
Jorge Pulido
CUNY City College
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Vessel for a Thermochemical Heat Storage System" (2012). CUNY Academic Works.
http://academicworks.cuny.edu/cc_etds_theses/621
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Exploration of the Endothermic and Exothermic
Reactions of Calcium Oxide and Magnesium
Oxide and Design of a Vessel for a
Thermochemical Heat Storage System
THESIS
Submitted in partial fulfillment of
the requirement for the degree
Master of Engineering (Mechanical)
at
The City College of New York
of the
City University of New York
By
Jorge Pulido
August, 2012
Approved:
Professor Masahiro Kawaji, Thesis Advisor
CUNY Energy institute
Professor Feridun Delale, Chairman
Department of Mechanical Engineering
1
2
ABSTRACT
A high temperature Thermal Energy Storage (TES) system has been investigated for use
in solar thermal power plants or in vehicles to preheat the engine and/or the cabin in cold
weather. The idea is to store surplus thermal energy and then release it on demand to heat
a working fluid. The stored heat can be used to generate electricity after sunset or to
meet the peak loads. These would lead to an improvement in energy efficiency,
reductions in energy imports from foreign sources and total energy-related emissions.
The basic operating principle involved in the TES system is a thermochemical reaction
involving metal oxides such the calcium oxide (CaO) or magnesium oxide (MgO) and
water. In the output mode, an exothermic reaction is initiated when liquid water or steam
is injected into the metal oxide particle bed to produce Ca(OH)2 or Mg(OH)2. The heat
generated in this process can then be used to heat up a secondary flow of water or other
heat transfer fluid that passes through the TES system. In the charging phase, the bed will
be heated to dehydrate Ca(OH)2 or Mg(OH)2 in an endothermic reaction inside the TES
vessel. This research investigates the integration of thermal storage and heat transfer
technologies into a working system. Efficient heat exchange is vital as porous solid
particles of metal oxides have low values of thermal conductivity.
i
Acknowledgement
In first place I want to thank my advisor Professor Masahiro Kawaji of the CUNY’s
Energy Institute and Mechanical Engineering Department at City College of New York,
for his guidance, patience and for the opportunity he gave me. To Professor Yiannis
Andreopoulos who let me use part of his lab to do the experiments and for his always
amiable attitude. Also to master students Ravi Ramnanan-Singh, Randy Samaroo and
Han Yi who helped me in numerous facets of the experimental setup. Finally to my
brother, who always found a way to help me.
ii
General Index
ABSTRACT ......................................................................................................................... i
1 Introduction ...................................................................................................................... 1
1.1 Theoretical Framework ......................................................................................................... 2
1.2 State of the art ........................................................................................................................ 6
1.3 objectives ............................................................................................................................... 7
2 Construction of the experimental setup ........................................................................... 8
2.1 Material .................................................................................................................................. 8
2.2 Furnace................................................................................................................................... 9
2.3 Temperature measurement ..................................................................................................... 9
2.4 First container ...................................................................................................................... 10
2.5 Second container .................................................................................................................. 12
2.6 Container for test with steam ............................................................................................... 15
2.7 General purpose container ................................................................................................... 17
2.7.2 Sprinkler ........................................................................................................................ 18
2.7.3 Coil ................................................................................................................................ 19
2.7.4 Heater ........................................................................................................................... 19
3 Experimental Procedure ................................................................................................. 20
3.1 Dehydration ......................................................................................................................... 20
3.1.2 Dehydration with the general purpose container ........................................................ 21
3.2 Hydration ............................................................................................................................. 23
3.2.2 Hydration with the general purpose container ............................................................ 23
4 Results for Calcium hydroxide and magnesium hydroxide ........................................... 24
4.1 Calcium Hydroxide .............................................................................................................. 24
4.1.2 Dehydration .................................................................................................................. 24
4.1.3 Hydration ...................................................................................................................... 26
4.1.3.1 Hydrations with cold water........................................................................................ 29
4.1.4 Hydration with steam ................................................................................................... 29
4.1.5 Dehydration in the general purpose reactor ................................................................ 30
4.1.6 Hydration general purpose reactor .............................................................................. 31
4.2 Magnesium Oxide ................................................................................................................ 32
iii
4.2.2 Dehydration .................................................................................................................. 32
4.2.3 Hydration ...................................................................................................................... 33
4.2.4 Hydration with steam ................................................................................................... 36
5 Conclusions .................................................................................................................... 37
Annex 1: Blueprints of the second container……...…………………………………….39
Annex 2: Blueprints of the general purpose container………………….……………...50
Annex 3: Steps to assemble the attachment to the upper cover for the general purpose
container………………………………………………………………………………….59
References ......................................................................................................................... 62
Figures index
Figure 1: Energy flows (TWh) in the global electricity system.......................................... 2
Figure 2: Classification of thermochemical storage reactions ............................................ 4
Figure 3: Hydration/dehydration cycle for the calcium ...................................................... 5
Figure 4: Glass reactor ........................................................................................................ 6
Figure 5: Cooper and polyurethane..................................................................................... 6
Figure 6: Close loop reactor ................................................................................................ 7
Figure 7: Jewerly furnace.................................................................................................... 9
Figure 8: Thermocouple type K ........................................................................................ 10
Figure 9: Data acquisition board with USB carrier .......................................................... 10
Figure 10: Sugar shaker .................................................................................................... 11
Figure 11 Wire basket ....................................................................................................... 11
Figure 12: Base with insulation ........................................................................................ 12
Figure 13: Second container ............................................................................................. 13
Figure 14: Distribution of the holes .................................................................................. 13
Figure 15: Cap of the second container ............................................................................ 14
Figure 16: Configurations of the second container ........................................................... 14
Figure 17: Characteristic behavior of the small furnace ................................................... 15
Figure 18: Sugar shaker divided by mesh ......................................................................... 15
Figure 19: Container for test with steam........................................................................... 16
Figure 20: General purpose container ............................................................................... 17
Figure 21: Furnace Omegalux LMF-A550 ....................................................................... 18
Figure 22: Sprinkler .......................................................................................................... 18
Figure 23: Inner and outer coil.......................................................................................... 19
Figure 24: Electric heater .................................................................................................. 19
Figure 25: Jumps in the temperature reading .................................................................... 20
iv
Figure 26: Gas heater ........................................................................................................ 22
Figure 27: Hydration with steam ...................................................................................... 23
Figure 28: Funnel .............................................................................................................. 24
Figure 29: First successful dehydration ............................................................................ 25
Figure 30: Dehydration for two different sizes of lumps .................................................. 26
Figure 31: Typical hydration reaction for the CaO ........................................................... 27
Figure 32: Fast and slow reactions in the CaO ................................................................. 28
Figure 33: Super-hot hydrations ....................................................................................... 29
Figure 34: CaO hydration with steam ............................................................................... 30
Figure 35: Dehydration with the general purpose reactor ................................................ 31
Figure 36: Hydration with the general purpose reactor .................................................... 32
Figure 37: Magnesium dehydration .................................................................................. 33
Figure 38: Magnesium hydration ...................................................................................... 34
Figure 39: Slow magnesium hydration ............................................................................. 35
Figure 40: Steam magnesium hydration ........................................................................... 36
Tables Index
Table 1Insulation properties .......................................................................................................... 21
Table 2: Characteristics of the pipe and heater of the gas dehydrator ........................................... 22
v
vi
1 Introduction
Some statistics that indicate the current situation of fuels, energy consumption and
production have been reported by the International Energy Agency (IEA). For example,
81% of energy production in 2009 was from fossil fuels; the price per barrel of oil today
is 7 times higher than 25 years ago, the amounts of CO2 emissions as well as the rate of
energy consumption have doubled since the 70’s. Every day, it is more evident that
processes with higher energy efficiency are needed and that research in new technology
to produce energy is urgent.
The two most used types of energy are electricity and heat. In the case of electric energy,
the power plants are about 30 to 40% efficient depending on the thermodynamic cycles
used. In some energy systems where one can find low efficiencies; in a combustion
engine, only 20% of the fuel’s energy is used to generate work, while the rest is wasted in
the form of heat. Thermal Energy Storage Devices (TESD) can help to recover part of
this heat making the thermal cycles more efficient.
In figure 1, we can see that 63% of the thermal energy is lost in the generation of
electricity. Generally, the waste heat is released to the environment by cooling towers,
cooling water or flue gases. This surplus energy can be used with TESD in the production
of electricity in power plants fed by fossil fuels, nuclear fuels or even in solar thermal
plants. TESD can also be applied on a smaller scale in vehicles where the cabin needs to
be heated or to preheat the engine. The chemicals used in thermal storage, do not lose the
capacity of storage over time, so this concept can be used to supply energy after hours or
even months of storage.
1
Figure 1: Energy flows (TWh) in the global electricity system
1.1 Theoretical Framework
The thermal energy storage devices can be classified into three groups, sensible, latent
and chemical, according to the physical principles used. Each group has particular
characteristics that will be explained below.
Sensible Heat Storage: This kind of device is most popular commercially due to its
relative simplicity. The principle used is the sensible heat, defined as the heat received or
sensed by a body or a substance which does not change the molecular state of the
material. Generally this kind of storage consists of a solid or fluid, usually water, that is
heated, stored in a thermally isolated container or reservoir and then released to heat or
cool a space or pipe system. The amount of heat that can be stored depends on the
thermal characteristics of the fluid and the efficiency of the insulation used in the
reservoir. One of the problems of this system is that the difference between the fluid and
environment temperatures must be high. This represents bulky and expensive systems. A
second inconvenience is seen in the storage duration, that is not longer that two or three
days. The energy density storage is around 100 kJ/kg [1].
2
Latent Heat Storage: The operating principle of these devices is the heat absorbed or
released when a substance changes its phase (gas, liquid or solid). There are two ways to
store the heat: the first in which Phase Change Material (PCM) is kept in such way that
the phase change occurs as the environment’s temperature drops; in the second method
the PCM is maintained in a phase (gas or liquid), and when needed it is compressed or
decompressed freely or with a pump. Because the PCM also needs to be thermally
insulated, this energy storage lasts about the same period of time as the sensible heat
devices. The working fluid needs to be confined inside the device, so the presence of heat
exchangers is a must in this method. The stored energy density goes up to 250-330 kJ/kg
[1].
Chemical Heat Storage: Thermal energy is released or absorbed when new chemical
bonds are formed or broken between two or more molecules. Although in theory all the
new bonds generate heat, only a few generate enough heat to be useful. The principal
advantage is that the heat released is not a function of external conditions and the heat
can be stored indefinitely without any loss. Desirable characteristics of this technology
would be practical forward and backward reaction temperatures, fast reaction rates and
low cost of the components. These characteristics are what make chemical energy storage
so promising and are why this method is the subject of this work. In figure 2, we can see
a general classification of the most common chemical reactions used for heat storage. The
stored energy density goes up to 2 MJ/kg [1].
3
Figure 2: Classification of thermochemical storage reactions (from W. Wongsuwan
at al. Applied Thermal Engineering 21 (2001) 1489-1519)
4
CaO/ Ca(OH)2 Cycle
The reactions of CaO and MgO are classified as a solid-fluid reaction, monovariant and
inorganic, where the solid is a metal oxide. CaO is a white powder with a consistency
very similar to talcum powder and its theoretical density is 3350 kg/m3 but in the powder
form used in most experiments, the density is 508.6 kg/m3. The typical reaction cycle is
shown in figure 3.
Figure 3: Hydration/dehydration cycle for the calcium
For one mol of Ca(OH)2 at room temperature, it is necessary to add 148.6 kJ of energy to
decompose it into CaO and H2O; this reaction occurs at a temperature over 500ºC. This
energy can come from exhaust gases from a boiler, an engine, or a solar thermal power
plant. This part of the cycle can be considered as the charging process. Then the calcium
oxide can be hydrated with water at room temperature, releasing 63.6 kJ/mol. The energy
efficiency in this particular cycle would be 42.8%, but one can increase this efficiency
using 23.5 kJ/mol and the 61.5 kJ/mol lost in the cooling of the CaO and in the
condensation of the water.
Furthermore, if the hydration reaction is done at a higher temperature instead of at 25ºC,
the energy efficiency could also be improved. The use of nickel oxide as a dopant for the
dehydration reaction could be considered another way to increase the efficiency, but its
effect on the hydration is unknown as of now. The efficiency could be reduced after
many cycles because of the reaction between CaO and CO2, which forms calcium
carbonate, CaCO3. The calcium carbonate can be eliminated by increasing the
temperature and the pressure of the dehydration every several cycles.
Most of this work is conducted with CaO; nevertheless some experiments with
magnesium oxide (MgO) were performed. An energy balance of the reaction shows that
less energy is released with magnesium oxide, only 81 kJ/mol in comparison with 148.6
kJ/mol released by the calcium oxide reaction.
5
1.2 State of the art
A
Azpiazu et al. [2] used two configurations for the analysis of the reaction. One of them,
maybe the simplest design, was a device made of glass beakers, as shown in figure 4. The
smallest beaker had the calcium oxide to be tested. Then this container was immersed in a
second beaker with liquid antifreeze used as thermal media to measure the heat delivery
of the exothermal reaction. Finally, this assembly was positioned in a bigger beaker that
worked as a thermal isolation chamber to avoid air currents which would cool down the
reactor. A Differential Scanning Calorimetry (DSC), was used to measure the heat of
reaction, calculate the specific heat changes, enthalpies and the kinetics of the reaction.
CaO/Ca(OH)2
Aqueous antifreeze
Air insulation
Figure 4: Glass reactor
The second prototype was similar to a heat exchanger and was made of a copper box with
copper fins inside that are in contact with the calcium oxide bed and connected to a space
with antifreeze as shown in figure 5. Then this box was then placed inside a second box
made of polyurethane.
Figure 5: Cooper and polyurethane
6
Thermocouples are used to measure the temperatures of the calcium bed and the
antifreeze. With this configuration, not only is the behavior of the hydration/dehydration
evaluated, but also calculated is the usable energy that can be extracted from the reaction.
With thermo-gravimetry or differential calorimetry, it is possible only to evaluate the
behavior of the reaction. As previously shown, a very simple device can demonstrate how
easily energy from exothermic reactions can be used. But this device was not designed to
achieve several cycles or manipulate variables that have an influence over the reaction.
Ogura et al. [3] proposed a configuration of two containers connected with pipes as
shown in Figure 6: one was a high temperature reactor and contained the CaO/Ca(OH)2;
the other container was the low temperature reactor that acted as a condenser and
evaporator for water.
Figure 6: Close loop reactor
The dehydration is done in the high temperature reactor by the heaters and the resulting
water vapor goes to the low temperature reactor where it is condensed. For the hydration
reaction, the water was heated to the boiling point and due to a difference in pressure the
vapor flowed to the calcium oxide container. The temperature at which the water reacts
could be controlled by the vacuum pump.
The last configuration is the most commonly used. It is common to see variations like a
second set of high and low temperature reactors, coils or fins in the reactors to heat or
cool a thermal fluid (like an antifreeze) or to achieve dehydration. Also several trays or
levels are in the high temperature reactors. The common characteristic is the
manipulation of the pressure to increase or reduce the boiling point of the water from
100ºC.
1.3 objectives
The objective of the present study is to explore the behavior of the dehydration and
hydration reactions with calcium oxide and magnesium oxide in order to understand
7
which variables can be controlled to produce several thermal charge and discharge
cycles. A consequence of this exploration will be the development of a device that works
with liquid water or steam at atmospheric pressure. This device could be considered as a
prototype of a TESD that will be used for further investigations.
2 Construction of the experimental setup
The project is divided into three different stages. The first stage is an exploration of the
dehydration and hydration reactions. In the second stage, the aim is to find a way to
perform as many thermal cycles as possible and to explore the effect of different
variables. In the last stage, the goal is to see how a TESD can be constructed.
In all the stages, the conditions are extreme, with temperatures up to 900ºC (1652ºF); also
a very detailed monitoring of the temperature is important. For these reasons the design
of the container represents an important part of this project.
2.1 Material
The experiment needs a container that does not react with water, CaO/Ca(OH)2 or MgO/
Mg(OH)2, does not leak particles and also tolerates the high temperatures of the
dehydration and hydration reactions. Other important consideration is that the container
must be as light as possible, since a heavy container will require a lot of energy just to
heat the container material; a similar situation occurs when measuring the heating and
cooling times, as the thermal inertia of the container would give a false impression of the
speed of the chemical reactions.
The best material is stainless steel. It has a melting point of around 1,510ºC (2,750ºF) so
the temperatures reached in the present experiment will not affect the structural integrity
of the container. This also allows a light design, and this material is innocuous to the
reaction of the MgO or the CaO and water. It is important to say, however, that the
thermal conductivity of steel is not the best for this experiment in comparison with
aluminum, copper, or other materials as shown in table 1.
Table 1: Thermal conductivity for different metallic materials
W/(mºK)
Aluminum
250
Brass
109
Copper
401
Steel, Carbon 1%
43
Stainless Steel
16
8
BTU/(fthr*ºF)
144
63
232
25
9.2
This low thermal conductivity is compensated by the high yield strength of the stainless
steel, that allows the construction of a light container of thin walls and hence a low
thermal mass.
2.2 Furnace
The best option was an electric jewelry furnace shown in figure 7; as it could reach
temperatures above the dehydration limit 550ºC (1022ºF) for a long period of time,
necessitated by mind the low thermal conductivity of the magnesium and calcium oxide
and hydroxide. The furnace selected for the exploratory stage was the model MPM1C
from Wenesco.
Figure 7: Jewelry furnace
2.3 Temperature measurement
For temperature reading a type K thermocouple was used, which has the components
chromel (90 percent nickel and 10 percent chromium) and Alumel (95% nickel, 2%
manganese, 2% aluminum and 1% silicon). It has a temperature range of 0º to 927ºC
(32º to 1700ºF), with a sensitivity of approximately 41 µV/°C. The thermocouple is
inside an immersion probe made of 316 stainless steel with a grounded tip as shown in
the figure 8; this means that the thermocouple wires are physically attached to the inside
of the probe wall. This results in good heat transfer from the outside, through the probe
wall to the thermocouple junction.
9
Figure 8: Thermocouple type K
The thermocouples (fig 8) were connected to a pc using a data acquisition board from
National Instruments with 16 channels, model NI 9213 and its USB carrier model 9162
shown in figure 9. Labview was used to configure the data sampling frequency of the
readings and export the file to Microsoft Excel.
Figure 9: Data acquisition board with USB carrier
2.4 First container
In the first part of the project a container that fits inside a small furnace was necessary.
To meet all the constraints mentioned before, it must be made of stainless steel.
Furthermore, to manufacture a container to do the first experiments without having any
experience could be expensive, so a very simple and commercial container, was need, a
sugar shaker, was selected as shown in figure 10.
10
A
A
Mass: 127g
90 mm
1 mm
50,4 mm
Figure 10: Sugar shaker
This container would be used for most cycles. This particular model comes with a cap
and a pipe that later would be used to make the container for the tests with steam
injection. It was necessary to remove the plastic parts of the container and then burn the
epoxy glue.
In figure 11 it can be seen one of the wire baskets that were made to safely manipulate
the container when hot. This is not a stainless steel wire, but it would not be in contact
with the calcium oxide at any moment. The configuration of the basket was a strong
structure even at high temperatures, but if it breaks the container could hit the chamber of
the furnace and damage it or spill out the powder.
Figure 11 Wire basket
In the hydration process, the thermocouple tends to rotate the container when it is
inserted into the bed; to solve this and also reduce heat losses, a stable, heavy and
thermally isolated base was built, shown in figure 12.
11
Figure 12: Base with insulation
2.5 Second container
Using the first container some important characteristics of the reactions, processes and
methodology were identified.




In chapter 3, it will be explained that it is necessary to add more water than the
stoichiometric amount, but too much water would cool down the powder, so a
proper distribution of the water will be important.
It would be easier to track the behavior of a large quantity of CaO or MgO,
because a large mass of powder will be less sensitive to fluctuations in the
dehydration temperature, the amount of water added for the hydration reaction
and the thermal influence of the container’s steel wall.
In the dehydration process, the possibility to collect the steam coming from the
container was considered.
The stainless steel is expensive and as the experiment progresses, the container
will undergo design changes, so the container must have the possibility to be
updated and have as little welding and as few permanent parts as possible.
In response to these requirements, a second container was designed. It is shown in figure
13.
12
Figure 13: Second container
Some of the parts deserve a short explanation. First the water injection attachment; it is
composed of a disk that holds three small pipes that spread water. To do this it has holes
that are not aligned as shown in figure 14.
Figure 14: Distribution of the holes
Figure 13 shows one green and one purple pipe. The green pipe is for the thermocouple,
and the purple pipe injects water. In the figure they appear to be cut off, but their length
can be checked on the plans in Appendix 1. There is also a green ring in the image. This
ring acts as a spacer, with two purposes: In the hydration reaction, it forms a “pool”,
giving time to the calcium or magnesium to absorb the water; second, this is where the
steam is going to accumulate before exiting by the same pipe that is used to pour the
water in, avoiding condensation inside the chamber. The cap shown in figure 15 has a
shoulder to hold the different attachments together; the cap also has a groove with space
for a wire that allows manipulating the container when hot.
13
Shoulder
Thread
Groove
Figure 15: Cap of the second container
The threads on the container and the cap are standard for a commercial pipe of that size,
and its length allows adjusting the cap without any accessory, giving the possibility for
different configurations. For example, we can see the container without connectors in the
first picture of figure 16, and without the spacer in the second figure. This design made a
versatile tool.
Figure 16: Configurations of the second container
Some problems were detected while the container was in use. The design does not use
any standard parts; everything must be machined from raw materials, generating
difficulties and delays for modifications or repairs. Even though the container was
designed to fit inside the small furnace, the two long pipes for the injection of water and
the thermocouple did not allow the furnace lid to fully close, so this increased the time to
complete a reaction. Furthermore, the furnace presented an oscillatory behavior in the
temperature as the control system tried to maintain it constant. This can be seen in figure
17.
14
Temperature (ºC)
Temperature furnace curve
800
700
600
500
400
300
200
100
0
0
20
40
Time (min)
60
80
Figure 17: Characteristic behavior of the small furnace
When the top lid of the furnace is open, the temperature is less stable and the peaks and
valleys are more frequent. Hence the plateau, characteristic of the dehydration, is more
difficult to identify. Finally, the container needs a lot of steel, reducing the usable space,
which is in contradiction with the requirements that were initially mentioned about the
low thermal mass the container should have.
2.6 Container for test with steam
For the test with steam, it is necessary to boil the water in a separate compartment and
then inject the vapor into the container that has the calcium or magnesium oxide powder.
The initial concept was to divide the sugar shaker in two chambers using a mesh, as
shown in figure 18. The lower compartment will have liquid water and after applying
heat the water would begin to boil and the vapor would cause a reaction.
A
A
Powder
Mesh
Water
.
Figure 18: Sugar shaker divided by mesh
This design has some problems; first regardless of how fine the mesh is, there will always
be calcium or magnesium oxide that passes through the mesh, reacting with water,
15
resulting in a loss of control of when and in what quantity the reaction occurs. Another
problem the reduced sizes of the chambers, so the amount of water is restricted to the
small space under the mesh. However, the principal problem is that it would be necessary
to extract the powder, then refill the container with water after each experiment and that
is another source of error.
The solution to these obstacles was a second sugar shaker. Using the cap and the pipe that
comes with the container, it is possible to make a separate chamber for the water and
connect it to the container with the calcium or the magnesium oxide, this configuration as
shown in figure 19.
Figure 19: Container for test with steam
The two caps (blue) and the pipe (red) are a single piece to avoid any loss of vapor; we
can see that the container has two holes, one for the thermocouple and the other is the
hole where the excess of vapor escapes.
This design also has some limitations. The piece composed by the caps and the pipe was
not easy to weld so only a single welded point was joinined each cap to the pipe. This,
plus the fact that between the caps and the containers is a pressure fitting, ended with
rupture of both joints. The daily manipulation made that the mouth of the water container
got deformed, breaking the delicate seal that keeps the vapor in the chambers. Moreover,
in the manipulation some powder escapes through the holes of the pipe in very small
quantities; but with several cycles the amount of powder that reacts could be significantly
reduced.
16
2.7 General purpose container
The biggest problem with previous designs was the size. Any kind of system to spray the
water, cool down the container, take readings in more than one point, division of the
chambers, etc, is very hard to design in such small dimensions. The goal of the next
design was to maximize the size of the container, taking into account the conditions we
established before and what was learned with the last designs. The result was a container
made of a thin stainless steel sheet, with a simple flange system to attach different
accessories by only replacing the caps, as it can be seen in figure 20.
Figure 20: General purpose container
In figure 20, one of the multiple configurations can be seen, which in particular shows a
helical heating element, with a single pipe for water injection. The space that contains the
powder is composed by the flanges (blue) and a cylinder (black); without any attachment
inside, the capacity is 2513.7 cm3 (more than 15 times the capacity of the biggest
container until then). Due to the fact that the container can work with water or with low
pressure steam it is important to guarantee a tight seal, hence a high temperature-high
pressure material was found; it is made of laminated vermiculite core with carbon steel,
that tolerates temperatures up to 982.2ºC (1800ºF) and can be cut with sheet metal shears.
It is important to remember that that a high repeatability of the thermal cycling is desired,
thus the methodology must be less manual and more automated. The first step in this
direction was to maximize the size of the container in coordination with the size of the
chamber of the new furnace (Omegalux LMF-A550), shown in figure 21. This furnace
has a chimney that could be used to pass small pipes to the container; there is a space of
47.6 mm between the furnace’s roof and the container for any accessory. This gives the
possibility to make the hydration and dehydration reactions inside the furnace, and also
allow the automation of the furnace operation.
17
Figure 21: Furnace Omegalux LMF-A550
The initial configuration for the experiments with this container has a sprinkler for the
water, an electric heater and a cooper coil. The coil can be used as a heat exchanger to
cool down the container, to warm up the thermal fluid or also for the dehydration. Here
each of them is explained briefly.
2.7.2 Sprinkler
The sprinkler, shown in figure 22, is made of copper, which has a high fusion point
1084.62 °C (1984.32 °F) and is very easy to bend or form. The spiral shape allows us to
cover most of the container’s diameter without couplings or Swagelok. It has 20 holes
with a 1.1mm in diameter to spray the water.
Figure 22: Sprinkler
18
2.7.3 Coil
The coil is composed of two copper tubes, whose size was selected with the condition that
the areas inside the small coil and the ring outside of it were the same. A similar norm
was applied in its length. They are attached together by a Yor-Lok compression fitting
made of stainless steel. The surface area in contact with the powder is 462 cm2. Its
assembly can be checked in figure 23.
Figure 23: Inner and outer coil
2.7.4 Heater
The heater is a single phase electric heater that works with 120 V.AC. It is not
commercially available, so it was manufactured specifically for this experiment. The
helical shape, in figure 24, gives a lot of surface with minimum of volume.
Figure 24: Electric heater
19
3 Experimental Procedure
For the first three containers the procedure was almost the same. The general purpose
container used a particular method depending on the accessories that were used.
3.1 Dehydration
For the sugar shaker, we use the wire basket to put it inside the furnace; the wire basket is
not needed for the second container because it has a groove for its own wire. The
dehydration is characterized by a change in the slope in the graph of the temperature vs
time. The change of the slope is produced by the absorption of heat and to a lesser extent
by the change in the thermal conductivity of the bed. The dehydration was usually done
at 700 ºC, at which temperature the inflection point is still visible, within the range of the
thermocouple. The reaction is fast enough to do several experiments in a day. Other
temperatures were explored; lower temperatures allow to see a more evident plateau, but
consumes more time. In the case of higher temperatures, it is hard to find the exact point
where the dehydration begins, and the thermocouple can shows jumps in the readings, as
it was showed in figure 25. Apparently, these jumps happen because the metallic probe of
the thermocouple begins to bend under the high temperature and its own weight.
Dehydration
700
Temperature (ºC)
600
500
400
300
200
100
0
0
20
40
60
Time (min)
80
Figure 25: Jumps in the temperature reading
20
100
This can be avoided if the thermocouple is hung, even though the lifetime of the sensor is
reduced, so either way it is suggested not to go over 700ºC frequently.
After the dehydration process is finished it is necessary to wait until the container cools
down, which can take up to one hour in the case of the second container; when the
purpose is to make as many cycles as possible, this is not efficient. To accelerate the
process, the container is submerged in water, holding it with some pliers from the basket
or the wire in the case of the second container. It is important to highlight that this is safe
as long as we are using small containers and the water does not get inside the container. If
water touches the powder at this temperature, particles will jump out of the container (if it
is open) becoming a safety hazard.
This process generates a dark scale, or very brittle flake on the exterior of the containers.
Keeping in mind that the container is stainless steel and that the oxidation of the steel is a
slow process, the corrosion can be disregarded. On the other hand, based on the color of
the material, how brittle it is (observable when the basket wire is then bended) and noting
that it is almost exclusively present in the exterior of the container, it could be inferred
that the material is one of the crystal structures formed in a tempering or quenching
processes (martensite, austenite, pearlite). The problem with the flakes is that it falls very
easily from the container, so in several cycles the thickness of the container would be
reduced. Until now this has not represented a considerable problem, but it should be kept
in mind in the future.
3.1.2 Dehydration with the general purpose container
The dehydration can be achieved by three different methods. With the large furnace, just
put the container inside the chamber and set the temperature; as with the small furnace,
700ºC is the temperature recommended. If the hydration process is going to be done
inside the furnace, the pipes for the water injection and the coil need to be placed through
the chimney before the container is installed.
The second method is to use the helical heater inside the container, which can be hung
from the upper cover of the container that also holds the coil and the sprinkler; with a
Variac transformer the temperature can be set. For this setup we need to cover the
container with high temperature thermal insulation to reduce the heating time, the power
consumption and the risk of accidents. The characteristics of this material is presented on
table 2.
Table 1Insulation properties
Material
Alumina silica
Heat Flow Rate (K-factor)
@ 426.6 ºC (800ºF):
Density
21
0.65
128.14 Kg/m3
Thickness
Maximum temperature
50.8 mm
1093.3ºC
The heater has a temperature limit of 871ºC, because it is submerged in the calcium oxide
powder, a low conductive material. The powder temperature can increase really fast and
burn the heater. It is necessary to have a thermocouple in contact with the heater and
reduce the voltage when the temperature gets closer to that limit. The electric power
supplied to the heating coil is one of the principal parameters to be automated.
A third way to achieve dehydration is by injecting hot gas; for this a flexible heating tape
is wrapped around a nickel-chromium(or copper) tubing, as shown in figure 26, where air
from a compressor is heated and then passed through the copper coil inside the container.
Some characteristics of the heater and the pipe appear in table 3.
Figure 26: Gas heater
maximum heat output of 760ºC
Heater
1/8" thick, 1/2" wide
10' Length, 520 Watts, 120 VAC with Plug
3/4" OD, .620" ID, .065" Wall, 3' Length
72% nickel, 14-17% chromium, and 6Tubing
10% iron
Temperature Range: -200° to 650° C
Table 2: Characteristics of the pipe and heater of the gas dehydrator
22
3.2 Hydration
As was mentioned before, the sugar shaker is placed into the heavy base (figure 12); 60
mL of water is added to 50 g of calcium. The reaction takes several seconds and the
temperature rises to around 200ºC. The second container is heavy so it is not necessary to
put it inside the base; this container is not as versatile as the sugar shaker, so it was used
only a few times. For the hydration with steam the reactor in figure 19 is used; one of the
containers is filled with water, then the container with calcium oxide closes the first
container and the entire device is then placed on a hot plate, as shown in figure 27, where
water boils and the vapor reaches the powder in the upper chamber. In the test with
vapor, the reaction takes several minutes, in part because it takes a long time for the water
to boil.
Figure 27: Hydration with steam
3.2.2 Hydration with the general purpose container
The sprinkler in figure 22 is used with a funnel, a hose and a small ball valve to inject the
water, shown in figure 28. With the valve closed, the funnel is filled with water and then
raised to increase the potential energy of the fluid; in this way the speed of the injection
can be controlled with the height of the funnel.
23
Figure 28: Funnel
This simple system allows full control in the amount of water without using a pump, but
it will be hard to automate in the future; a future design for this system needs to recover
the water from the dehydration and store it a bladder-pressure tank that will be
pressurized at the moment of the injection with a compressor that can be automated.
4 Results for Calcium hydroxide and magnesium hydroxide
4.1 Calcium Hydroxide
4.1.2 Dehydration
The experiment began with 50 grams of Ca(OH)2; it is known that the dehydration starts
at a temperature higher than 512ºC [1], so the furnace was initially set at 550ºC.
However, the oscillatory behavior of the furnace, prevented us from recognizing if and
when the reaction took place. It was when the furnace temperature reached 600ºC that a
change in the temperature gradient became appreciable.
24
Dehydration
800
700
Temperature (ºC)
600
532.3
500
Bed temperature
400
Furnace
temperature
300
200
100
0
0
20
40
60
80
100
120
140
Time (min)
Figure 29: First successful dehydration
In figure 29, 532.3ºC appears to be the point where the dehydration reaction begins, while
at 100ºC there is a plateau that corresponds to the vaporization of remaining moisture in
the Ca(OH)2 bed.
The next step was to conduct experiments with different sizes of Ca(OH)2 lumps. To
prepare the lumps, an aluminum container was filled with approximately 250 grams of
Ca(OH)2. Then water was added forming mud that is heated at 200ºC (a temperature high
enough to vaporize the water) to form a hard bed that could be broken and separated into
different sizes. The dry shell was very brittle, in fact it was easier to make small lumps
than big ones; then with the help of three sieves the particles were separated into four
sizes: bigger than 12.5 mm, between 6.3 and 12.5 mm, between 2 and 6.3 mm and
smaller than 2mm. Several hydration-dehydration cycles were repeated with all sizes, but
there were not an appreciable difference in the dehydration process, as can be seen in the
dehydration processes for two different lumps sizes in figure 30.
25
Dehydration
800
700
Temperature (ºC)
600
500
6.3<Lumps size<12.5
2<Lumps size<6.3
400
300
200
100
0
0
10
20
30
40
50
Time (min)
Figure 30: Dehydration for two different sizes of lumps
4.1.3 Hydration
In the first test of hydration, 18 mL of water were added to 50 grams of calcium oxide,
the stoichiometric quantity. But that amount of water did not produce a temperature
increase that could be interpreted as an undeniable exothermic chemical reaction. Hence,
the amount of water was increased until it was seen that with 60 ml of water all the
calcium was hydrated almost at the same time.
The CaO and the Ca(OH)2 beds are very porous, able to store a lot of water beyond the
stoichiometric quantity necessary for the reaction. When water reaches the CaO, even
parts at the same depth as layers that have already reacted could stay dry; this explains
why even when the thermocouple was at the bottom, the temperature rise was small. For
this reason it was necessary to inundate the container just enough to hydrate the most
external stratum and ensure that all the calcium reacts and produces heat.
Due to the porosity of the CaO bed, the water takes a little time to be absorbed by the
solid bed. On the other hand we see that it is important that the bed reacts at the same
time to avoid that the unreacted calcium absorbs heat already generated. This gives
importance to a system or device to spread water in the reactors. The sugar shaker was
the container most used for the cycles; because of its size, it was very hard to design a
26
sprinkler, but this was achieved in the general purpose reactor. It can be said that the
speed at which the water reacts with the CaO, depends on the absorption speed and
mostly the water pouring speed.
Thirty four hydration tests were done with liquid water and only with a few exceptions
the behavior was almost the same as shown in figure 31. First, there is an almost vertical
line that shows a very fast temperature increase, then a peak in temperature after which a
typical cooling curve descends to 100ºC.
Hydration
200
180
174.77
Temperature (ºC)
160
140
120
100
80
60
40
20
0
0
20
40
60
80
100
Time (sec)
Figure 31: Typical hydration reaction for the CaO
It is seen that in only a few seconds the temperature reaches a peak 70% higher than the
boiling point. The subsequent cooling curve and plateau are a result of the cooling effect
of the vapor leaving the Ca(OH)2 bed. The speed of the reaction, the speed of the cooling
and the maximum temperature reached varied a little among the experiments.
27
Hydration
180
160
Temperature (ºC)
140
120
100
80
Series1
60
Series2
40
20
0
0
50
100
150
200
Time (sec)
250
300
350
Figure 32: Fast and slow reactions in the CaO bed
The hypothesis that the reaction degrades over several thermal cycles, making the
reactions slower and cooler can be discarded. One slow and cool hydration curve, like the
series 2 in figure 32, can be followed in the next cycle by a fast and hot hydration curve,
like the series 1 in the same figure; the opposite is also true.
One hypothesis that explains slow and cool reactions is related with how fast the water is
poured into the container. Moreover, even when the cycles are done with a relatively
homogeneous powder bed, there are smaller particles, that with the manipulation are
decanted and dragged by the water to the bottom, forming a more dense and less porous
base; this affects the speed of absorption and therefore the speed of the reaction. With a
slower reaction, it is logical to think that there will be a lower peak; in turn, a lower peak
means fewer vapors cooling the bed and a flatter cooling curve. The presence of this
more dense bed at the bottom can be confirmed when the container is emptied and the
dense layer is exposed.
In the experiments with the CaO lumps, no relation between the reaction behavior and the
presence of the lumps could be established. No lump size survived beyond the fourth
cycle. Trying to maintain the stone consistency of the lumps, the hydrations began with
35 ml of water, but again it was found that there was not a full reaction in the calcium
28
oxide bed. Thus, the amount of water was increased in several tests up to 60 ml, but the
more water was used, the fewer cycles the lumps lasted.
4.1.3.1 Hydrations with cold water
Some of the cycles presented a peak in temperature almost twice higher than most
experiments. At the beginning there was not a clear cause for these super-hot hydrations.
Then, 10 cycles with water that was close to the freezing point offered a hint: the tests
with cold water resulted in peak temperatures from 280ºC to 400ºC. This result was
unexpected and although it is sure that the low temperature water is the cause, it is still
not clear why this happened, In figure 33, the behavior of two of this super-hot reactions
can be seen.
Hydration
450
400.9
400
343.03
Temperature (ºC)
350
300
250
200
150
100
50
0
0
100
200
300
400
500
Time (sec)
Figure 33: Super-hot hydrations
4.1.4 Hydration with steam
The reaction with steam was found to be slower than with water. The steam took more
time to reach and react with the bed, but the peak temperatures were in the same range as
with the hydration with liquid water. Because there is steam inside the container, the
cooling process after the peak reaches only 100ºC, where the temperature is maintained
due to the continuous injection of vapor. Other new situation in some hydration tests was
the presence of secondary temperature peaks after the highest peak. This can be explained
29
by the rupture of lumps formed through several cycles. These lumps reacted with the
vapor that still flowed through the reactor. These smaller peaks can be seen in figure 34.
Hydration
160
140
Temperature (ºC)
120
100
80
60
40
20
0
0
10
20
30
40
50
Tíme ( min)
60
70
80
Figure 34: CaO hydration with steam
In some experiments, once the 100ºC plateau was reached, the hot plate was turned off to
check the amount of water that remained in the container; it can be seen that it took as
little as 30ml of water to produce a reaction. This could be explained because the vapor
(as any gas) tends to expand and fill its container regardless of its amount, and we could
fill the sugar shaker with only 30 ml of steam instead of 60 ml of liquid water. This was a
situation that could compensate for the slow reaction.
It is important to say that in 28 cycles with steam, 2 cycles did not go beyond 100ºC. It is
not easy to give an explanation for that until the process is automated, where hundreds of
thermal cycles could produce a good statistical data.
4.1.5 Dehydration in the general purpose reactor
In figure 35, the start of the hydration reaction when is in the furnace took around three
hours. It is expected that with other methods this time can be reduced.
30
Dehydration
800
700
Temperature ()ºC
600
500
400
300
200
100
0
0
50
100
150
200
Time (min)
250
300
350
400
Figure 35: Dehydration with the general purpose reactor
4.1.6 Hydration general purpose reactor
In the hydration plot (figure 36) we find that the reaction was slower than in the smaller
containers. Due to the bigger mass, the cooling curve is also less steep. The blue line
confirms how important a water injection system is, even when 1300ml of water was
used. Since no reaction took place in the peripheral region. It is important to mention that
the first hydration test in this container yielded a peak temperature of 442ºC in the central
region and 373.5ºC in the peripheral, suggesting that other water injection systems should
be tested.
31
Hydration
180
160
Temperature (ºC)
140
Peripheral thermocouple
Central thermocouple
120
100
80
60
40
20
0
0
10
20
30
40
50
Time (min)
60
70
80
90
Figure 36: Hydration with the general purpose reactor
4.2 Magnesium Oxide
4.2.2 Dehydration
For magnesium oxide tests, 50 grams were used again and the temperature of the furnace
was kept at 700ºC. The dehydration reaction occurred at 400ºC in accordance with the
available literature on this process. Figure 37 is a record of this dehydration reaction.
32
Dehydration
700
600
500
Temperature (ºC)
407.3
400
Bed temperatue
Furnace temperature
300
200
100
0
0
10
20
30
40
50
Time (min)
Figure 37: Magnesium dehydration
The consistency of the magnesium oxide after several cycles was less porous, more
compact and the particles attached to the walls of the container, in an almost
diametrically opposite behavior to the CaO or the Ca(OH)2.
4.2.3 Hydration
The hydration test began with 60 ml of water without any reaction. Considering that
probably too much water was added, cycles with 50 and 40 ml were done until 10
repetitions were completed without obtaining a positive result. It was considered that an
initial high temperature is necessary to start the reaction, so tests with warm water were
made. The first test was with 60 ml of water at 60ºC and the result is shown in figure 38;
the water warmed up the magnesium until the first peak, then it cooled relatively slowly
until it reached a minimum, but then the temperature increased again until it reached
100ºC where it stayed for a long time. After which, the bed cooled down back to the
room temperature.
33
Hydration
120
Temperature (ºC)
100
80
70.5
65.1
60
40
20
0
0
5
10
15
20
25
Time (min)
Figure 38: Magnesium hydration
The temperatures in the peak and valley, as well as the speed of the reaction, changed for
each cycle. At the beginning it seemed that there was a minimum temperature necessary
for the reaction, but the cycle with 60 ml of water at 60ºC was done again, showing a
different result that contradicted this hypothesis (figure 39).
34
Hydration
60
Temperature (ºC)
50
40
30
20
10
0
0
50
100
150
Time (min)
200
250
300
Figure 39: Slow magnesium hydration
After one hour it was possible to see an indication of a reaction, evidenced by a change in
the slope. It seems the different curve shapes in the hydration cycles are related with the
low porosity of the bed, rather than with temperature of the water. This is coherent with
the different peaks, valleys and durations of the reaction; if a specific water temperature
would be necessary, the range of these temperature in the reactions would be closer in
different hydrations tests. A hypothesis similar to that of the Ca(OH)2 where finer
particles were decanted, is proposed to explain this effect. However, the slower
absorption speed effect is accentuated by the naturally higher density of the magnesium
oxide.
The temperature never exceeded 100ºC, even when water at 95ºC was added. In the
experiments, it was seen that 40 ml is the proper quantity for the hydration reaction with
the magnesium oxide. When more water is added, after the 100ºC plateau the remaining
water stayed on the bed and was not absorbed as in the Ca(OH)2. This pool over the bed
boiled and a lot of steam emanating from the container was observed; in one particular
hydration test with 50 grams of magnesium oxide and 100 ml of water, 20 ml were left in
the container and considering the relatively low absorptivity of the bed, it can be said that
around 40 ml of water was transformed into steam. This can be a good situation despite
the low temperatures reached in the reaction.
35
4.2.4 Hydration with steam
With steam the behavior was different as shown in figure 40. The MgO bed temperatures
exceed 100ºC in 5 min, then there was a very drastic change in the slope, from very
vertical to almost horizontal; the temperature rose to 107.8ºC rapidly and then began a
very slow cooling that ended again at 100ºC.
Hydration
120
107.8
Temperature (ºC)
100
80
60
40
20
0
0
10
20
30
Tíme (min)
Figure 40: Steam magnesium hydration
36
40
50
5 Conclusions
The amount of water and how it is added is probably the most important variable. The
temperature, amount, water phase, and the speed at which it is poured, determines the
peak temperature that can be reached. The porosity of the bed material is not a negligible
characteristic. However, in the case of CaO the porosity is very high, but for MgO, it is
less, to the point that the water can form a pool over the bed. The best method to achieve
high temperatures in hydration reaction could be a topic for a separate investigation.
According to the present results, the use of lumps of any size in the dehydration or
hydration steps for the tests with steam water is innocuous.
Between the MgO and CaO, it is the latter that offers higher temperatures, indicating that
this reaction could be more promising for use in thermal storage devices in power plants
and in vehicles.
The MgO does not offer as high temperatures as CaO; but because it is less porous, it
releases steam easier than the CaO, a characteristic that also could be exploited in other
applications.
The use of cold water, close to the freezing point, generated higher temperatures than
with room temperature water, the reason for this is unknown. Cooling the water to this
point could represent an obstacle to overcome.
There is still a lot to study such as, dehydration with a hot gas and electric heaters,
hydration at different bed temperatures, dehydration under different pressures, hydration
with cold water, and the effect of catalysts and additives in the dehydration and hydration
processes for both, CaO and MgO.
37
Annex 1
Blue prints of the second container
9
7
6
8
5
3
Item
Number
Title
1
From
Quantity
1
Internal pipe
Stainless
steel
1
2
Bottom
Stainless
steel
1
3
Spray
Stainless
steel
1
4
Inyector
Stainless
steel
3
5
Spacer
Stainless
steel
1
6
Colector
Stainless
steel
1
7
Condenser
Stainless
steel
1
8
External pipe
Stainless
steel
1
9
Thermocouple pipe
Stainless
steel
1
4
2
Material
City College of New York
Container for water
Jorge Pulido
Esc: 1 : 1
Mechanical Ing.
Assamble
To
Date: 2/28/2011
39
Thesis
Stainless steel
Masahiro Kawaji
Item#: 0
2
1
Item
Number
From
City College of New York
Container for water
Jorge Pulido
Esc: 2 : 1
Title
Material
Quantity
1
Internal pipe Stainless steel
1
2
Bottom
1
Stainless steel
Thesis
Mechanical Ing.
Stainless steel
Container Assamble
To
Masahiro Kawaji
Date: 2/28
Item#: 0
40
3
The three holes of each pipes
point to the center
Item
Number
4
From
City College of New York
Container for water
Jorge Pulido
Esc: 2 : 1
Title
Material
Quantity
3
Spray
Stainless steel
1
4
Inyector Stainless steel
3
Thesis
Mechanical Ing.
Stainless steel
Inyectors Assamble
To
Masahiro Kawaji
Date: 2/28
Item#: 0
41
2
3
Item
Number
Title
Material
Quantity
1
Colector
Stainless steel
1
2
Condenser
Stainless steel
1
3
Thermocouple pipe Stainless steel
1
1
From
City College of New York
Container for water
Jorge Pulido
Esc: 2 : 1
Mechanical Ing.
Conectors
To
Date: 2/28
42
Thesis
Stainless steel
Masahiro Kawaji
Item#: 0
43
O 1.50
From
2.00
City College of New York
Container for water
Jorge Pulido
Esc: 1 : 1
4.00
Thread 1 1/2-6 UNC
Mechanical Ing.
Thesis
Stainless Steel
Internal Pipe
To
Masahiro Kawaji
Item#: 1
Date: 2/28
.020
O 1.50
From
City College of New York
Container for water
Jorge Pulido
Esc: 2 : 1
Mechanical Ing.
Bottom
To
Date: 2/28
Thesis
Stainless steel
Masahiro Kawaji
Item#: 2
O .148
6.39
From
O3/16"
City College of New York
Container for water
Jorge Pulido
Esc: 2 : 1
Thesis
Mechanical Ing.
Stainless steel
Thermocouple pipe
To
Masahiro Kawaji
Date: 2/28
Item#: 9
44
45
O 1/4"
O 1/4"
O 1.50
From
O 1/8"
City College of New York
Container for water
Jorge Pulido
Esc: 2 : 1
O 1/4"
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Mechanical Ing.
Thesis
Stainless Steel
Spray
To
Masahiro Kawaji
Item#: 3
Date: 2/28
46
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1.36
NOTE: All the holes are of the
same size. Each set of holes are in
faces at 90º of the adyacents
faces
O 3/32"
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From
.73
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City College of New York
Container for water
Jorge Pulido
Esc: 1 : 1
1.36
2.000
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O 1/4"
Mechanical Ing.
Thesis
Stainless Steel
Inyector
To
Masahiro Kawaji
Item#: 4
Date: 2/28
O .18
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O 1.500 1 1/2-6 UNC
From
City College of New York
Container for water
Jorge Pulido
Esc: 2 : 1
Mechanical Ing.
Spacer
To
Date: 2/28
Thesis
Stainless steel
Masahiro Kawaji
Item#: 5
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.375
O3/16"
O 1/4"
O 1.500
From
City College of New York
Container for water
Jorge Pulido
Esc: 2 : 1
Mechanical Ing.
Colector
To
Date: 2/28
47
Thesis
Stainless steel
Masahiro Kawaji
Item#: 6
48
12.00
From
City College of New York
Container for water
Jorge Pulido
Esc: 1 : 1
Mechanical Ing.
Thesis
Stainless Steel
Condenser
To
Masahiro Kawaji
Item#: 7
Date: 2/28
O .180
49
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O 1.64 O 1.07
1/16"
1/16"
From
City College of New York
Container for water
Jorge Pulido
Esc: 2 : 1
1.50
1.31
1.37
Mechanical Ing.
Thesis
Stainless Steel
External Pipe
To
Masahiro Kawaji
Item#: 8
Date: 2/28
1 1/2-6 UNC
50
3
8
7
From
2
City College of New York
Container for water
Jorge Pulido
Esc: 1 : 1.11
1
6
4
9
Big Coil
Injection Coil
8
9
1
1
1
1
1
1
2
2
1
Quantity
Mechanical Ing.
Thesis
Stainless Steel
General assamble
To
Masahiro Kawaji
Item#: 0
Quantity: 1
Copper
Copper
Copper
Small Coil
Stainless steel
7
Upper cover
5
Stainless steel
Heating element Stainless steel
Pipe
4
Stainless steel
Silicone
Stainless steel
Material
6
Flange
Gasket
Lower cap
Title
3
2
1
Item
Number
5
Annex 2
Blueprints of the general purpose container
51
3/8
"
60°
From
City College of New York
Container for water
Jorge Pulido
Esc: 1 : 2
97,04
.062 "
Mechanical Ing.
Thesis
Stainless Steel
Lower cover
To
Masahiro Kawaji
Piece#: 1
Quantity: 1
8.625 "
97.04
O 6.5 "
52
From
3/8"
City College of New York
Container for water
Jorge Pulido
Esc: 1 : 2
60°
.062 "
Mechanical Ing.
Thesis
Stainless Steel
Flange
To
Masahiro Kawaji
Piece#: 3
Quantity: 2
8.625 "
53
From
City College of New York
Container for water
Jorge Pulido
Esc: 1 : 2
.062 "
Mechanical Ing.
Thesis
Stainless Steel
Pipe
To
Masahiro Kawaji
Piece#: 4
Quantity: 1
111,48
169,08
54
Heater Diameter: 0.26"
Number of turns: 3
4,7
From
0,7
1,2
Mechanical Ing.
Heating element
To
Masahiro Kawaji
Piece#: 6
Quantity: 1
Extension regardless of the length of the electric terminal
City College of New York
Container for water
Jorge Pulido
Esc: 1 : 1
2,2
55
60°
7/16
"
O
12,7
7/1
6"
60,56
5/16"
5/16"
2,56
From
33,56
24,56
5/16"
5/1
3/8"
"
7/16
1,56
7/16"
75,56
66,56
33,06
19,9
38,5
57,1
75,7
City College of New York
Container for water
Jorge Pulido
Esc: 1 : 2
6"
8.6 "
Mechanical Ing.
Thesis
Stainless Steel
Upper cover
To
Masahiro Kawaji
Piece#: 5
Quantity: 1
.062 "
56
1,8
2
R1
Pipe: O.D.= 1/4" I.D.= 0.186"
Number of turns: 3 left-handed
O 71,93
41,46
11,82
From
City College of New York
Container for water
Jorge Pulido
Esc: 1 : 1
68,57
14,46
Mechanical Ing.
Thesis
Coper
Small Coil
To
Masahiro Kawaji
Piece#: 7
Quantity: 1
R
1
1,82
57
Pipe: O.D.=1/4" I.D.=0.186"
Number of turns: 3
right-handed
11,83
O 138,56
From
40,13
City College of New York
Container for water
Jorge Pulido
Esc: 1 : 2
1,82
R1
14,91
R 11,37
Mechanical Ing.
Thesis
Copper
Big Coil
To
Masahiro Kawaji
Piece#: 8
Quantity: 1
68,57
58
Pipe: O.D.= 1/4" I.D.= 0.19"
Number of turns: 2
Parametric equation:
x= 4.8xtxcos(t)+4.13
y= 4.8xtxsin(t)+9.5
157,33
From
City College of New York
Container for water
Jorge Pulido
Esc: 1 : 2
This end is closed
Mechanical Ing.
Thesis
Copper
Big Coil
To
Masahiro Kawaji
Piece#: 9
Quantity: 1
R 11,4
8
16,17
Annex 3
Steps to assemble the attachment to the upper cover for the general purpose container.
Step 0: Upper cover with compression fittings
Step 1: Injection coil
59
Step 2: Small coil added
Step 3: Electrical heater added
60
Step 4: External coil added
61
References
[1] M.N. Azpiazu, J.M. Morquillas, A. Vazquez, Heat recovery from a thermal energy
storage based on the Ca(OH)2/CaO cycle, Applied Thermal Engineering 23 (2003) 733–
741.
[2] Hironao Ogura, Tetsuya Yamamoto, Hiroyuki Kage, Efficiencies of
CaO/H2O/Ca(OH)2 chemical heat pump for heat storing and heating/cooling, Energy 28
(2003) 1479–1493, 2001.
[3] W.Wongsuwan, S. Kumar, P.Neveu, F.Meunier, A review of chemical heat pump
technology and applications, Applied Thermal Engineering 21(2003) 1489-1519.
[4] F. Schaube, L. Koch, A. Wörner, H. Müller-Steinhagen, A thermodynamic and
kinetic study of the de- and rehydration of Ca(OH)2 at high H2O partial pressures for
thermo-chemical heat storage, Thermochimica Acta 538 (2012) 9– 20.
[5] S. Fujimoto, E. Bilgen, H. Ogura, CaO/Ca(OH)2 chemical heat pump system, Energy
Conversion and Management 43 (2002) 947–960.
[6] S. Fujimoto, E. Bilgena, H. Ogura, Dynamic simulation of CaO/Ca(OH)2 chemical
heat pump systems, Exergy, an International Journal 2 (2002) 6–14.
[7] Hironao Oguraa, Energy Recycling System Using Chemical Heat Pump Container,
Energy Procedia 14 (2012) 2048 – 2053
[8] Hironao Ogura, Shokrat Abliz, Hiroyuki Kage, Studies on applicability of scallop
material to calcium oxide/calcium hydroxide chemical heat pump, Fuel Processing
Technology 85 (2004) 1259– 1269
[9] F. Schaube, A. Wörner, H. Müller-Steinhagen, High temperature heat storage Using
gas-solid eactions, Pfaffenwaldring 38-40, 70569 Stuttgart.
[10] M.A. Hamdan, S.D. Rossides, R. Haj Khalil, Thermal energy storage using thermochemical heat pump, Energy Conversion and Management (2012)
[11] Jaume Cot-Gores, Albert Castell, Luisa F.Cabeza, Thermochemical energy storage
and conversion: A-state-of-the-art review of the experimental research under practical
conditions, Renewable and Sustainable Energy Reviews 16 (2012) 5207–5224.
[12] K. Darkwa, Thermochemical energy storage in inorganic oxides: an experimental
evaluation, Applied Thermal Engineering Vol. 18, No. 6, pp. 387±400, 1998.
[13] Yukitaka Kato, Kei Kobayashi and Yoshio Yoshizawa, Durability to repetitive
reaction of magnesium oxide/water reaction system for a heat pump, Applied Thermal
Engineering Vol. 18, Nos 3-4, pp. 85-92, 1998.
62
[14] BY P. J. Anderson., F. Horlcaknd, J. F. OLIVER, Interaction of Water with the
Magnesium Oxide Surface, 01 January 1965 on http://pubs.rsc.org |
doi:10.1039/TF9656102754, 1965
63