U.S. patent application number 13/982060 was filed with the patent office on 2013-11-21 for temperature control system.
This patent application is currently assigned to JAPAN OIL, GAS AND METALS NATIONAL CORPORATION. The applicant listed for this patent is Yuzuru Kato, Kentarou Morita. Invention is credited to Yuzuru Kato, Kentarou Morita.
Application Number | 20130306299 13/982060 |
Document ID | / |
Family ID | 46602531 |
Filed Date | 2013-11-21 |
United States Patent
Application |
20130306299 |
Kind Code |
A1 |
Morita; Kentarou ; et
al. |
November 21, 2013 |
TEMPERATURE CONTROL SYSTEM
Abstract
The temperature control system of the present invention is a
temperature control system for recovering reaction heat inside a
reactor in which an exothermic reaction takes place, thereby
controlling a temperature inside the reactor. The temperature
control system is provided with a coolant drum in which a liquid
coolant is accommodated in a vapor-liquid equilibrium state, a heat
removing unit which is disposed on the reactor to internally
circulate the liquid coolant supplied from the coolant drum, a
temperature determining unit which determines a temperature inside
the reactor, and a pressure controller which controls pressure
inside the coolant drum. The pressure controller controls the
pressure inside the coolant drum based on a difference between an
actual temperature inside the reactor determined by the temperature
determining unit and a preset temperature value inside the reactor,
thereby controlling the temperature of the liquid coolant inside
the coolant drum.
Inventors: |
Morita; Kentarou;
(Shinagawa-ku, JP) ; Kato; Yuzuru; (Shinagawa-ku,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Morita; Kentarou
Kato; Yuzuru |
Shinagawa-ku
Shinagawa-ku |
|
JP
JP |
|
|
Assignee: |
JAPAN OIL, GAS AND METALS NATIONAL
CORPORATION
Minato-ku, Tokyo
JP
INPEX CORPORATION
Minato-ku, Tokyo
JP
NIPPON STEEL & SUMIKIN ENGINEERING CO., LTD.
Shinagawa-ku, Tokyo
JP
JAPAN PETROLEUM EXPLORATION CO., LTD.
Chiyoda-ku, Tokyo
JP
COSMO OIL CO., LTD.
Minato-ku, Tokyo
JP
JX NIPPON OIL & ENERGY CORPORATION
Chiyoda-ku, Tokyo
JP
|
Family ID: |
46602531 |
Appl. No.: |
13/982060 |
Filed: |
January 17, 2012 |
PCT Filed: |
January 17, 2012 |
PCT NO: |
PCT/JP2012/050853 |
371 Date: |
July 26, 2013 |
Current U.S.
Class: |
165/279 |
Current CPC
Class: |
F28F 27/00 20130101;
B01J 8/001 20130101; C10G 2/34 20130101; F28D 2021/0077 20130101;
B01J 2219/00081 20130101; B01J 19/0013 20130101; F28D 2021/0064
20130101; B01J 2219/00067 20130101; F28D 2021/0033 20130101; B01J
2219/00065 20130101; B01J 2219/00162 20130101; B01J 2219/002
20130101; B01J 2219/00063 20130101; B01J 2219/00238 20130101; B01J
2219/00213 20130101; C10G 2/30 20130101 |
Class at
Publication: |
165/279 |
International
Class: |
F28F 27/00 20060101
F28F027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2011 |
JP |
2011-018263 |
Claims
1. A temperature control system for recovering reaction heat inside
a reactor in which an exothermic reaction takes place, thereby
controlling a temperature inside the reactor, the temperature
control system comprising: a coolant drum in which a liquid coolant
is accommodated in a vapor-liquid equilibrium state; a heat
removing unit which is disposed on the reactor to internally
circulate the liquid coolant supplied from the coolant drum; a
temperature determining unit which determines a temperature inside
the reactor; and a pressure controller which controls pressure
inside the coolant drum, wherein the pressure controller controls
the pressure inside the coolant drum based on a difference between
an actual temperature inside the reactor determined by the
temperature determining unit and a preset temperature value inside
the reactor, thereby controlling the temperature of the liquid
coolant inside the coolant drum.
2. The temperature control system according to claim 1, wherein the
exothermic reaction is the Fischer-Tropsch synthesis reaction.
3. The temperature control system according to claim 1, wherein a
coolant refilling unit which refills the liquid coolant into the
coolant drum is installed inside the coolant drum, and the coolant
refilling unit is disposed inside a gas phase unit of the coolant
drum.
4. The temperature control system according to claim 3, wherein a
spray unit which sprays the liquid coolant to the gas phase unit is
formed at the coolant refilling unit.
5. The temperature control system according to claim 4, wherein the
coolant refilling unit is formed in a tubular shape and the spray
unit includes a through hole which is formed at the coolant
refilling unit.
6. The temperature control system according to claim 2, wherein a
coolant refilling unit which refills the liquid coolant into the
coolant drum is installed inside the coolant drum, and the coolant
refilling unit is disposed inside a gas phase unit of the coolant
drum.
7. The temperature control system according to claim 6, wherein a
spray unit which sprays the liquid coolant to the gas phase unit is
formed at the coolant refilling unit.
8. The temperature control system according to claim 7, wherein the
coolant refilling unit is formed in a tubular shape and the spray
unit includes a through hole which is formed at the coolant
refilling unit.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a temperature control
system.
[0003] Priority is claimed on Japanese Patent Application No.
2011-18263, filed on Jan. 31, 2011, the content of which is
incorporated herein by reference.
[0004] 2. Description of Related Art
[0005] In recent years, as a process for synthesizing liquid fuels
from natural gas, the GLT (Gas To Liquids: liquid fuels synthesis)
technique has been developed. This GLT technique includes the steps
of reforming a natural gas to produce a synthesis gas containing a
carbon monoxide gas (CO) and a hydrogen gas (H.sub.2) as main
components, synthesizing liquid hydrocarbons using this synthesis
gas as a feedstock via the Fischer-Tropsch synthesis reaction
(hereinafter, also referred to as the FT synthesis reaction) and
then hydrogenating and fractionating these liquid hydrocarbons to
produce liquid fuel products such as naphtha (raw gasoline),
kerosene, gas oil, wax and the like.
[0006] In the FT synthesis reaction, a reactor which carries out an
exothermic reaction can convert the synthesis gas rich in hydrogen
gas and carbon monoxide gas to hydrocarbons by using a catalyst.
The FT synthesis reaction is an exothermic reaction and also quite
narrow in its temperature range where the reaction proceeds
appropriately, by which it is necessary to strictly control a
reaction temperature inside the reactor, while recovering reaction
heat which has been generated.
[0007] As a heat recovery system for recovering reaction heat
inside a reactor, there is known, for example, a constitution
described in Patent Document 1 given below. In this heat recovery
system, a jacket-equipped conduit is disposed inside the reactor,
and water which is supplied to an external boiler is circulated to
a jacket space inside the jacket-equipped conduit, thereby
recovering the reaction heat inside the reactor.
PRIOR ART DOCUMENT
Patent Document
[0008] Patent Document 1: Published Japanese Translation No.
2008-537507 of the PCT International Application
SUMMARY OF THE INVENTION
Technical Problem
[0009] However, in the conventional heat recovery system, since the
water which has been supplied to the boiler is only circulated to
the jacket space, there is a risk that temperature control is not
appropriately performed in the reactor. In this instance,
properties of hydrocarbons generated by the FT synthesis reaction
are unstable and even disrupt operations of upgraded facilities at
subsequent steps, which pose a problem.
[0010] Further, the temperature control is not appropriately
performed in the reactor. As a result, where a temperature inside
the reactor is shifted from a temperature range appropriate for the
FT synthesis reaction to a high temperature side, the FT synthesis
reaction goes out of control to result in abrupt temperature
elevation. Thus, there are posed various problems such as
deterioration and damage in catalysts, in addition with a problem
on strength of the reactor.
[0011] The present invention has been developed in light of the
above circumstances, and has an object of providing a temperature
control system which is capable of quickly dealing with a change in
temperature inside a reactor and controlling the temperature inside
the reactor with high accuracy.
Solution to Problem
[0012] The temperature control system of the present invention is a
temperature control system for recovering reaction heat inside a
reactor in which an exothermic reaction takes place, thereby
controlling a temperature inside the reactor. The temperature
control system is provided with a coolant drum in which a liquid
coolant is accommodated in a vapor-liquid equilibrium state, a heat
removing unit which is disposed on the reactor to internally
circulate the liquid coolant supplied from the coolant drum, a
temperature determining unit which determines the temperature
inside the reactor, and a pressure controller which controls the
pressure inside the coolant drum. Further, the pressure controller
controls the pressure inside the coolant drum based on a difference
between an actual temperature inside the reactor determined by the
temperature determining unit and a preset temperature value inside
the reactor, thereby controlling the temperature of the liquid
coolant inside the coolant drum.
[0013] In the present invention, since the liquid coolant is
accommodated inside the coolant drum in a vapor-liquid equilibrium
state, a correlation between pressure inside the coolant drum and a
temperature of the liquid coolant is kept substantially equal.
Through utilization of this fact, the pressure controller controls
the pressure inside the coolant drum, thereby directly controlling
the temperature of the liquid coolant supplied from the coolant
drum to the heat removing unit, then controlling a recovery amount
of reaction heat inside the reactor by the heat removing unit and
the temperature inside the reactor.
[0014] That is, in the temperature control system, first, the
pressure controller controls the pressure inside the coolant drum
based on a difference between the actual temperature inside the
reactor and a preset temperature value. Then, depending on a
correlation with the vapor-liquid equilibrium state inside the
coolant drum, the liquid coolant inside the coolant drum undergoes
a change in temperature. Since the liquid coolant is supplied to
the heat removing unit, an amount of heat recovered by the heat
removing unit is changed, depending on the change in temperature of
the liquid coolant. Then, the temperature inside the reactor can be
controlled by adjusting the amount of heat to be recovered.
[0015] In the temperature control system of the present invention,
the exothermic reaction may be the Fischer-Tropsch synthesis
reaction.
[0016] In the temperature control system of the present invention,
a coolant refilling unit which refills the liquid coolant into the
coolant drum may be installed inside the coolant drum, and the
coolant refilling unit may be disposed inside a gas phase unit of
the coolant drum.
[0017] According to the present invention, the coolant refilling
unit is disposed inside the gas phase unit of the coolant drum.
Therefore, even if a liquid coolant lower in temperature than
inside the coolant drum is refilled from the coolant refilling
unit, heat will transfer between this liquid coolant and steam
inside the coolant drum, by which the liquid coolant is equal in
temperature to the steam and accumulated at a liquid phase unit
inside the coolant drum. Thus, no difference is caused in
temperature between the gas phase unit and the liquid phase unit
inside the coolant drum.
[0018] In the temperature control system of the present invention,
a spray unit which sprays the liquid coolant to the gas phase unit
may be formed at the coolant refilling unit.
[0019] According to the present invention, the coolant refilling
unit is provided with the spray unit which sprays the liquid
coolant to the gas phase unit. Therefore, the liquid coolant
refilled from the coolant refilling unit is increased in surface
area, by which heat is allowed to move more smoothly between the
steam and the liquid coolant inside the coolant drum.
[0020] In the temperature control system of the present invention,
the coolant refilling unit may be formed in a tubular shape, and
the spray unit may include a through hole which is formed at the
coolant refilling unit.
Advantageous Effects of Invention
[0021] According to the temperature control system of the present
invention, the pressure controller controls the pressure inside the
coolant drum based on a difference between the actual temperature
inside the reactor and a preset temperature value. Thereby, the
temperature of the liquid coolant supplied from the heat removing
unit can be changed in order to adjust the amount of heat recovered
at the heat removing unit. Therefore, where an actual temperature
inside the reactor is higher than a preset temperature value, the
pressure inside the coolant drum is controlled so as to increase
the amount of heat recovered by the heat removing unit. Further,
where the actual temperature is lower than a preset temperature
value, the pressure inside the coolant drum is controlled so as to
decrease the amount of heat recovered by the heat removing unit. It
is, thus, possible to control the temperature inside the reactor
within a preset temperature value intended.
[0022] Further, the pressure controller controls the pressure
inside the coolant drum so as to be of equal correlation with the
temperature of the liquid coolant supplied to the heat removing
unit. Thereby, the temperature of the liquid coolant supplied from
the coolant drum to the heat removing unit can be directly
controlled. Therefore, the liquid coolant of which the temperature
has been controlled outside the coolant drum is supplied to the
coolant drum, thus making it possible to control the temperature
inside the reactor more quickly than a method for controlling the
temperature of the liquid coolant inside the coolant drum. It is,
thereby, possible to reliably control the temperature so that an
exothermic reaction will not go out of control resulting in abrupt
temperature elevation inside the reactor.
[0023] As described above, in the method for supplying the liquid
coolant controlled for the temperature outside to the coolant drum
to control the temperature of the liquid coolant inside the coolant
drum, the liquid coolant supplied from outside is less likely to
become similar in temperature to the liquid coolant inside the
coolant drum, thus resulting in a risk that the temperature of the
reactor may not be controlled with high accuracy.
[0024] According to the temperature control system of the present
invention, the exothermic reaction is the Fischer-Tropsch synthesis
reaction which is quite narrow in temperature range where the
reaction proceeds appropriately. Thus, it is possible to remarkably
obtain the above-described effect.
[0025] According to the temperature control system of the present
invention, the coolant refilling unit is disposed inside the gas
phase unit of the coolant drum. Therefore, heat will move
efficiently between the liquid coolant and the steam inside the
coolant drum in the gas phase unit. Thereby, no difference was
found in temperature between the gas phase unit and the liquid
phase unit inside the coolant drum, even if the liquid coolant
refilled from the coolant refilling unit is not preheated outside
the system. Then, the pressure and the temperature inside the
coolant drum can be kept so as to give a correlation in a
vapor-liquid equilibrium state.
[0026] According to the temperature control system of the present
invention, heat is allowed to transfer more smoothly between the
steam and the liquid coolant inside the coolant drum. Thereby, the
pressure and the temperature inside the coolant drum can be kept
reliably so as to give a correlation in a vapor-liquid equilibrium
state.
[0027] According to the temperature control system of the present
invention, since the spray unit includes the through hole formed on
the coolant refilling unit, it is possible to reliably spray the
liquid coolant.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a schematic flowchart which shows a temperature
control system of one embodiment of the present invention.
[0029] FIG. 2 is a lateral cross-sectional view of a coolant drum
shown in FIG. 1.
[0030] FIG. 3 is a cross-sectional view in a width direction of the
coolant drum given in FIG. 1.
[0031] FIG. 4 is the other cross-sectional view in a longitudinal
direction of a coolant drum of one reference example in the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] Hereinafter, an explanation will be made for an embodiment
which is the best mode of the present invention by referring to the
drawings 1 to 4. It is noted that in FIG. 2 and subsequent
drawings, the constituents the same as those appearing in the
flowchart of FIG. 1 will be given the same reference signs, with an
explanation omitted here.
[0033] (Temperature Control System)
[0034] As shown in FIG. 1, a temperature control system 20 feeds
water (a liquid coolant) stored in the coolant drum 1 in a
vapor-liquid equilibrium state by a pump 4 from the bottom of the
coolant drum 1 to a heat removing tube (heat removing unit) 7
inside a reactor 5 which carries out the Fischer-Tropsch synthesis
reaction (an exothermic reaction) and allows the water to partially
evaporate inside the heat removing tube 7 by reaction heat
associated with the exothermic reaction which occurred in the
reactor 5, thereby recovering the reaction heat.
[0035] Further, a mixed phase fluid made up of steam and water in
which the water has partially evaporated in the heat removing tube
7 is returned to the coolant drum 1 through a return line 12
leading to the coolant drum 1, while the steam is supplied to a
steam user outside the system through a steam outlet line 11. A
steam trap (not shown) may be installed downstream from the steam
outlet line 11.
[0036] Still further, refilled water (a liquid coolant) in an
amount corresponding to the steam supplied outside the system is
refilled through a refilled water line 10. A refilled amount of the
refilled water is adjusted by a level adjusting valve 2 based on
determination results by a level determination unit 17 which
determines a water level (liquid level) inside the coolant drum
1.
[0037] In the above-described flowchart, based on determination
results by a temperature determining unit 6 which determines a
temperature inside the reactor 5 which carries out an exothermic
reaction, a pressure controller 18 which controls the pressure
inside the reactor 5 adjusts an amount of steam supplied from the
steam outlet line 11 to outside by cascade control, thereby
controlling the temperature of the reactor 5 which carries out the
exothermic reaction. The temperature determining unit 6 may be
provided with a plurality of temperature sensors (not shown) which
are arranged apart from each other in a vertical direction, for
example, on the reactor 5. It is, thereby, possible to determine a
mean value of individual temperatures determined by these
temperature sensors as the temperature inside the reactor 5.
[0038] Hereinafter, a detailed explanation will be made for the
above-described control.
[0039] A steam phase (gas phase unit) and a water phase (liquid
phase unit) inside the coolant drum I are kept in a vapor-liquid
equilibrium state. Therefore, the pressure of the steam phase
inside the coolant drum 1 and the temperature of the water phase
inside the coolant drum 1 are kept so as to give a constant
correlation.
[0040] Therefore, where a difference is found between the actual
temperature inside the reactor 5 determined by the temperature
determining unit 6 and a preset temperature value of the reactor 5
which carries out an exothermic reaction, the pressure controller
18 is actuated to change the pressure of the steam phase inside the
coolant drum 1.
[0041] Here, in the present embodiment, the pressure controller 18
controls the steam outlet line 11, a pressure adjusting valve 3
installed on the steam outlet line 11, and a pressure setting unit
9 which sets the pressure inside the coolant drum 1 via the steam
outlet line 11 by controlling the pressure adjusting valve 3.
Determination results made by the temperature determining unit 6
are sent out to the pressure setting unit 9. Also, the pressure
setting unit 9 calculates a difference between the actual
temperature and a preset temperature value inside the reactor 5
from the determination results, thereby controlling the pressure
adjusting valve 3 based on the difference and changing the pressure
of the steam phase inside the coolant drum 1.
[0042] As described so far, the steam phase inside the coolant drum
1 is changed in pressure, by which the water phase inside the
coolant drum 1 is changed in temperature (that is, the temperature
of water supplied to the heat removing tube 7 inside the reactor 5
which carries out an exothermic reaction), thus making it possible
to change the amount of heat recovered by the heat removing tube 7.
Then, it is possible to bring the temperature of the reactor 5
which carries out the exothermic reaction closer to a preset
temperature value.
[0043] In the present embodiment, the temperature of the water
phase inside the coolant drum 1 can be determined by a thermometer
8 installed at an end of the coolant drum 1 side in a line 13
through which water is supplied from the coolant drum 1 to the heat
removing tube 7 by using the pump 4. Further, in the present
embodiment, the coolant drum 1, the line 13, the heat removing tube
7, and the return line 12 constitute the system through which water
as a liquid coolant is circulated.
[0044] (Coolant Drum)
[0045] Next, an explanation will be given in detail for the coolant
drum 1 of the temperature control system 20.
[0046] As shown in FIG. 2 and FIG. 3, inside the coolant drum 1, a
refilled water line internal port (coolant refilling unit) 14
connected to the refilled water line 10 is extended along the
longitudinal direction of the coolant drum 1. The refilled water
line internal port 14 is arranged in the steam phase.
[0047] One or more holes (through holes) 15 are formed on a side
wall 14a of the refilled water line internal port 14 along an axis
direction thereof, and one or more holes 15 are also formed at an
end 14b of the port. Then, these holes 15 constitute sprinkling
units (spray units) 19 which sprinkle (spray) refilled water from
the refilled water line internal port 14 into the steam phase. It
is noted that the hole 15 may be a sprinkling nozzle.
[0048] Further, a return line internal port 12a connected to the
return line 12 is also installed inside the steam phase of the
coolant drum 1. A mixed phase fluid made up of steam and water,
some of which has evaporated in the heat removing tube 7 is
supplied into the coolant drum 1 from the return line internal port
12a. The return line internal port 12a is positioned further above
from the refilled water line internal port 14 and arranged at a
position away from above in the perpendicular direction of the
refilled water line internal port 14. Then, the return line
internal port 12a is bent to the refilled water line internal port
14, by which steam which has been circulated inside the return line
internal port 12a is to be supplied toward the refilled water line
internal port 14.
[0049] Next, an explanation will be made for actions of the
above-constituted coolant drum 1.
[0050] Refilled water is supplied at a position which is not
submerged from the refilled water line internal port 14, by which
heat is exchanged between the refilled water lower in temperature
and steam which is in a steam phase, thus avoiding a situation in
which the refilled water flows, as it is still cool, to the bottom
of the coolant drum 1. Further, the refilled water is sprinkled
through the holes 15 on the side wall 14a and the end 14b of the
refilled water line internal port 14. Thereby, the refilled water
can be in contact with steam at a greater area to improve the
efficiency of heat exchange, and heat can be exchanged more
efficiently between the refilled water which is lower in
temperature and the steam which is higher in temperature. Thus, no
difference is found between the temperature of the steam phase and
the water phase, and the pressure of the steam phase inside the
coolant drum 1 and the temperature of the water phase inside the
coolant drum 1 can be kept constant to give a correlation based on
a vapor-liquid equilibrium state. Thus, the temperature can be
controlled by the temperature control system 20 with high
accuracy.
[0051] As shown in the reference example in FIG. 4, when the
refilled water line internal port 14 is submerged into the coolant
drum 1, the lower-temperature refilled water greater in specific
gravity hardly flows out from side holes 16 which is formed in a
wall of the refilled water line internal port 14 but flows directly
to the bottom of the coolant drum 1. Therefore, a temperature
difference takes place between the steam phase and the water phase
inside the coolant drum 1. Then, the pressure of the steam phase
inside the coolant drum 1 is not properly correlated with the
temperature of the water phase inside the coolant drum 1, thus
resulting in a risk that the temperature control system 20 may not
control the temperature with high accuracy.
[0052] The present invention shall not be technically restricted to
the above-described embodiment but may be modified in various ways
within a scope not departing from the gist of the present
invention.
[0053] For example, in the above embodiment, the Fischer-Tropsch
synthesis reaction is carried out inside the reactor 5. However, as
long as an exothermic reaction is carried out inside the reactor 5,
the reaction may not be the Fischer-Tropsch synthesis reaction.
[0054] Further, in the above embodiment, as shown in FIG. 1, a
post-reaction fluid (a reaction product) is introduced from the top
of the reactor 5. However, a position in which the post-reaction
fluid is introduced from the reactor 5 can be changed, whenever
necessary. For example, the post-reaction fluid may be introduced
from a body (side wall) or a bottom of the reactor 5. The
post-reaction fluid may be introduced from a plurality of sites
such as the top, the body and the bottom of the reactor 5. A
position from which the post-reaction product is introduced may be
changed depending on, for example, a type of exothermic reaction
inside the reactor 5.
[0055] Further, in the above embodiment, water is used as a liquid
coolant but any coolant other than water may be used.
[0056] In the above embodiment, a mixed-phase fluid made up of
steam and water, some of which has evaporated at the heat removing
tube 7 is to return to the coolant drum 1 through the return line
12. However, the mixed phase fluid may not return to the coolant
drum 1.
[0057] In addition, a constituent of the above embodiment can be
substituted with a known constituent within a scope not departing
from the gist of the present invention, or the modified examples
may be combined whenever necessary.
INDUSTRIAL APPLICABILITY
[0058] The present invention may be applicable to any coolant drum
in general which is attached to a system which allows water
supplied to a heat removing tube to partially evaporate in a
reactor for carrying out an exothermic reaction to recover reaction
heat, thereby controls the reactor or a reaction temperature in
itself.
DESCRIPTION OF THE REFERENCE SIGNS
[0059] 1: Coolant drum [0060] 2: Level adjusting valve [0061] 3:
Pressure adjusting valve [0062] 4: Pump [0063] 5: Reactor [0064] 6:
Temperature determining unit [0065] 7: Heat removing tube [0066] 8:
Thermometer [0067] 9: Pressure setting unit [0068] 10: Refilled
water line [0069] 11: Steam outlet line [0070] 12: Return line
[0071] 12a: Return line internal port [0072] 13: line [0073] 14:
Refilled water line internal port [0074] 14a: Side wall [0075] 14b:
End of refilled water line internal port [0076] 15: Hole [0077] 16:
Side hole [0078] 17: Level determination unit [0079] 18: Pressure
controller [0080] 20: Temperature control system
* * * * *