U.S. patent application number 11/492624 was filed with the patent office on 2008-01-31 for concentrate solar thermal energy electric power plant logic boiler.
Invention is credited to Yanong Zhu.
Application Number | 20080022685 11/492624 |
Document ID | / |
Family ID | 38984751 |
Filed Date | 2008-01-31 |
United States Patent
Application |
20080022685 |
Kind Code |
A1 |
Zhu; Yanong |
January 31, 2008 |
Concentrate solar thermal energy electric power plant logic
boiler
Abstract
A logic boiler that consists of a concentrated solar energy
boiler, a thermal storage system, and a traditional fossil fuel
boiler is replacement of the traditional fossil fuel boiler in a
power plant for solar thermal electric power generation. The
thermal storage system or fossil fuel boiler compensates the output
steam of the solar energy boiler to provide on demand, reliable and
regulated steam for steam turbine. The controls sequences provide
results that maximize the output of the solar boiler while provide
the regulated and fast responded steam to the turbine. The control
sequences also provide an algorithm to store excessive thermal
energy from the solar energy boiler into the thermal storage
system. The power plant sees the logic boiler as a conventional
boiler without knowing the details of working sequences between the
solar boiler and fossil fuel boiler or thermal storage.
Inventors: |
Zhu; Yanong; (Santa Clara,
CA) |
Correspondence
Address: |
Yanong Zhu
Suite 100-3C, 2900 Gordon Avenue
Santa Clara
CA
95051
US
|
Family ID: |
38984751 |
Appl. No.: |
11/492624 |
Filed: |
July 25, 2006 |
Current U.S.
Class: |
60/660 |
Current CPC
Class: |
F22B 35/008 20130101;
F22B 33/00 20130101 |
Class at
Publication: |
60/660 |
International
Class: |
F01K 13/02 20060101
F01K013/02 |
Claims
1. A logic boiler is designed to be in replacement of the
conventional boiler in a fossil fuel burned steam power plant, is
controlled and monitored by valves, redundant sensors and redundant
controllers, is taking the commands from the power plant controller
and send requested information back to power plant controller, is
with redundant circuits for reliabilities, provides stable, on
demand, and reliable steam to turbine, provides thermal storage
energy charge and discharge functions, consists of a steam mixer,
consists of a solar boiler and a thermal storage system, or
consists of a solar boiler and a fossil fuel boiler, or a solar
boiler and a thermal storage system and a fossil fuel boiler.
2. A logic boiler controller as set forth in claim 1 wherein said
controller consists of redundant boiler master computers, redundant
boiler local area networks, redundant solar tower boiler
controllers, optional redundant fossil fuel boiler controllers,
optional redundant thermal storage controllers, and redundant logic
level controllers with redundant drivers and redundant sensors.
3. A logic boiler steam mixer as set forth in claim 1 wherein said
mixer consists of sensors for monitoring the input steam
parameters, controllable valves for adjust input steam flow rate, a
buffer for helping to regulate the output steam conditions, a senor
for monitoring the steam parameters in the buffer, a controllable
value for adjust the output steam parameters, and a sensor for
monitoring the output steam parameters.
4. The redundant circuits as set forth in claim 1 wherein said
redundant circuits consist of computer or microprocessor reset
level circuits, the sensor redundancy circuits, and the redundant
driver circuits.
5. The thermal storage charge and discharge functions as set forth
in claim 1 wherein said thermal storage energy charge and discharge
functions are controlled by the logic boiler controller through
reroute the steam to thermal storage system and internal working
mode of the thermal storage system.
6. The computer or microprocessor reset level circuits as set forth
in claim 4 wherein said computer or microprocessor reset level
circuits consists of input and output buffers, and reset level
decoders, is controlled by the redundant computer or
microprocessor. The reset algorithm start with the level 1, if
failed, it will goes level 2, and then if failed again, it will go
next high level.
7. The sensor redundancy circuits as set forth in claim 4 wherein
said sensor redundancy circuits consists of at the least three set
of sensors and two pair of independent read out systems that
connect to microprocessor of redundant to each other.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a logic boiler constructed
from a concentrated solar thermal energy boiler and a fossil fuel
boiler or a thermal storage system for generating steam in a solar
energy electric power plant.
[0003] 2. Description of Prior Art
[0004] The concentrated solar thermal energy boiler provides clean
and fuel burning free steam.
[0005] The solar energy is not controllable. It is different from
daytime to evening; it is different from summer to winter, and it
different from good whether to bad whether. The uncontrollable
solar energy results that steam from the solar boiler is also not
controllable, and does not meet the stable and controllable
requirements of both large steam turbine and power grid.
[0006] The steam turbines, especially large steam turbines require
stable and controllable steam input, otherwise, the lifetime of the
turbine may be reduced or unexpected operating situations may be
occurred.
[0007] Additional to un-predictable solar flux, the concentrated
solar thermal energy boiler is also a complex device, it may
contains thousands components and controlled by sophisticated
computer programs.
[0008] For the fossil fuel boiler, when the steam is on a demand
for more, the controller can increase the fuel supply to raise the
output. For the concentrated solar energy boiler, the solar energy
supply is not controllable.
[0009] Since the steam from the solar boiler is fuel burning free,
so the power plant control system should set the solar boiler is
maximum mode to gain the maximum energy solar energy collections,
unless in emergency situations. The excessive energy from solar
boiler can be saved in the thermal storage system if the storage
system is installed. Otherwise, the solar energy collection areas
will be reduces to match the steam demands from the turbine and
power generator.
[0010] The steam-based power plants are based on much matured
technologies. In addition, the power grid has developed a protocol
to interface with the steam based power plant. For a large-scale
solar thermal energy power plant, it is very important not only to
provide solar electric power, it is also very important to provide
high quality electric to the grid. For the best interests of the
grid, the power plant should be able to send operating information
as well as receiving the commands from the grid. Since the energy
source of the concentrated solar energy electric power plant is not
controllable, therefore, a second energy source or buffer must add
to the power plant to provide the required the flexibilities.
[0011] From the power plant power of view, the logic boiler is
identical to a high performance fossil fuel boiler. The logic
boiler provide a set of current running parameters and predicted
parameters to the power plant controller while receiving the
commands from the power plant controllers.
BRIEF SUMMARY OF THE INVENTION
[0012] A logic boiler for steam-based power plant consists a master
controller, a concentrated solar energy boiler and a fossil fuel
boiler or thermal storage system. The logic boiler is a replacement
for the boiler of a conventional steam based power plant, and
provides a stable and controllable steam to the turbine for
electricity generations.
[0013] FIG. 1 shows the schematics of a power plant with a logic
boiler. Both fossil fuel boiler and thermal storage are included in
the schematics. In practice, only one of them is required, either
fossil fuel boiler or thermal storage.
[0014] The high-pressure water feeds into the solar boiler in the
central receiving tower, the fossil fuel boiler, and the thermal
storage. The output steam from three boiler and mixed at steam
mixer. The output of the steam mixer is then feed to steam
turbine.
[0015] The inputs and outputs of all components of the logic boiler
are equipped with sensors that measuring the water level,
temperature, pressure, and flow speed of the water and steam. All
information is send to logic boiler controller. The boiler
controller reads information from sensors and drives the valves
until pre-set running parameters are met. The boiler controller is
a computer based with redundancy in the case of the failure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 shows a schematic diagram of a power plant with a
logic boiler in accordance with the principles of the
inventions;
[0017] FIG. 2 shows a the relationship between power plant control
master, the boiler master computers, the boiler networks, the solar
tower boiler controllers, the fossil fuel boiler controllers, the
thermal storages, and the logic level controllers;
[0018] FIG. 3 shows a schematic diagram of the driver disable
functions for boiler controller redundancy controls;
[0019] FIG. 4 shows a schematic diagram of the reset logic of logic
boiler controllers;
[0020] FIG. 5 shows a schematic diagram of the steam mixer;
[0021] FIG. 6 shows a schematic diagram of a power plant with a
logic boiler that supports reheat of steam in accordance with the
principles of the inventions.
DETAILED DESCRIPTION OF THE INVENTION
[0022] The logic boiler consists of the solar boiler, the fossil
fuel boiler and thermal storage as shown in FIG. 1. The
high-pressure water from the steam condenser is pumped by 102 P1
and then feed into boilers. The water levels in the boilers are
monitored by sensors and controlled by logic boiler controller
through 114 V3, 113 V4, and 112 V5.
[0023] The values 114 V3, 113 V4, and 112 V5 are linear valves with
redundancy that they can response to the command from the boiler
controller to control the water flow rate, resulting control the
water levels in the boilers.
[0024] The outputs of the boilers are connected steam mixer through
valves 110 V9, and 108 V7. 110 V9, 108 V7, and 107 V8 are on and
off valves with redundancy for boilers to be online or offline from
the system.
[0025] The values 108 V7 and 115 V2 are thermal charge values with
redundancy. They are will be "on" when the thermal storage is on
charge mode, and will be "off" when the thermal storage is on
discharge mode.
[0026] 117 P2 adds pressure after the steam stored its energy in
the thermal storage and condenses into water format.
[0027] The mixer mixes the steam from the boilers following the
commands of the boiler controller. The detail structure of the
mixer is illustrated by FIG. 5. 504 S1, 505 S2, 506 S3, 514 S4, and
517 S5 are sensors for temperature, pressure and flow rate. 508
VL1, 510 VL2, 512 VL3, and 516 VL4 are linear values with
redundancy and controlled by the boiler controller. Buffer is a
steam storage unit for stabilizing the steam and better mixing.
[0028] FIG. 2 shows the structure of the schematic diagram of the
logic boiler controller. The power plant feed or receiving
information to or from the boiler master computers. The 202 boiler
master computer 1 and 203 boiler computer 2 are redundant to each
other. The boiler master computers are communicating with modules
in logic boilers through two redundant networks, 204 boiler net1
and 205 boiler net2.
[0029] Within the logic boiler controller, there are four models;
they are 206 and 207 solar tower boiler controller, 208 and 209
fossil fuel boiler controller, 210 and 211 thermal storage
controller, and 212 and 213 logic level controller.
[0030] The 206 and 207 solar tower boiler controller controls
concentrate mirrors and detail operation of the receivers.
[0031] The 208 and 209 fossil fuel boiler controls the traditional
fossil fuel boiler.
[0032] The 210 and 211 thermal storage controller controls the
thermal storage.
[0033] The 212 and 213 logic level controller controls the detail
operation of the logic boiler. It controls all values 214000 to
214nnn through and read all sensors 215000 to 215 mm. They are
microprocessor based with redundancy.
[0034] Each sensor (215000 to 215 nnn) contains three sub-sensors
and they are redundant to each other. Each sub-sensor has two
independent outputs and connected to two redundant microprocessors.
The active microprocessor will receive three independent readings
from each sensor. Only two readings in agreement will be uses, and
the third reading has to be within the critical range, otherwise
the alarm will be triggered.
[0035] The controller drivers (214000 to 214 mmm) are designed to
support redundancy. FIG. 3 shows the schematic diagram of the
disable function of the driver. Each value is connected with two
separated wires from two separate drivers of the logic level
controllers. When a driver output monitored by the sensors is not
in agreement with the intent states, this driver will be disabled
by it's redundant microprocessor through "high" state signal and
buffer 304 B2. By doing this, it will cut off the connection of
current driver and will allow the redundant driver to take over the
control of the value.
[0036] Each pare of the redundant computers are controlled through
the inter reset logic unit are illustrated in FIG. 4. The reset can
be at different levels, such as interrupt, reset, and disable.
[0037] There are three operation modes: solar boiler with thermal
storage; solar boiler with fossil fuel boiler; and thermal storage
with fossil fuel boiler.
[0038] When the solar boiler works with thermal storage, it
contains two operational states: thermal storage charge state and
thermal storage discharge state.
[0039] During the thermal storage charge state, the excessive
thermal energy will send to thermal storage through valve 108 V7.
The steam will deposit its energy and be condensed becoming water
through 118 the thermal energy exchange with the storage material.
The condensed water will be pumped by 117 P2 and send back to
boilers.
[0040] During the thermal storage discharge state, the steam from
the solar boiler is with parameter to maximize the solar receiving
efficiency. Since the solar energy is not a stable source, the
output of the thermal storage will be adjusted to compensate the
steam parameter from solar boiler and the needs of the turbine.
[0041] When the solar boiler is working with 119 fossil fuel
boiler, the operation is relative simple. The output of the fossil
fuel boiler will compensates the variation of the output of the
solar boiler and matches the demands of the steam turbine.
[0042] When 118 the thermal storage is used to provide steam for
the turbine, no need for the fossil fuel boiler to be online. But,
on the other hand, with the help of the fossil fuel boiler, the
total energy discharge of the thermal storage can be maximized.
[0043] FIG. 6 illustrates re-heater system for turbine. The
high-pressure output of 604 turbine is re-heated by heat exchange
605. The steam temperature from 607 steam mixer is higher than the
required temperature of the turbine. The higher temperature steam
deposits partial energy to the lower pressure steam and raise the
temperature of the middle pressure steam to boost the efficiency of
the thermal cycle.
* * * * *