U.S. patent application number 15/985389 was filed with the patent office on 2018-09-27 for alternative fuels analyzer.
The applicant listed for this patent is XRSciences LLC. Invention is credited to Thomas Atwell, Colin Charette, John Dascomb, Tom Gibbons, Jacob Lopp, Chaur-Ming Shyu.
Application Number | 20180275078 15/985389 |
Document ID | / |
Family ID | 51844128 |
Filed Date | 2018-09-27 |
United States Patent
Application |
20180275078 |
Kind Code |
A1 |
Charette; Colin ; et
al. |
September 27, 2018 |
Alternative Fuels Analyzer
Abstract
A process for preparing alternative fuels so that it is
acceptable for use in cement plants and other manufacturing
processes is detailed. This includes a material analyzer that can
detect trace contaminants in alternative fuels. This new analyzer,
combined with an associated method of processing the alternative
fuels allows users to blend the fuel to ensure that it is
acceptable for plant operations.
Inventors: |
Charette; Colin; (Carlsbad,
CA) ; Atwell; Thomas; (Carlsbad, CA) ;
Gibbons; Tom; (Carlsbad, CA) ; Lopp; Jacob;
(Carlsbad, CA) ; Shyu; Chaur-Ming; (Carlsbad,
CA) ; Dascomb; John; (Carlsbad, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
XRSciences LLC |
Carlsbad |
CA |
US |
|
|
Family ID: |
51844128 |
Appl. No.: |
15/985389 |
Filed: |
May 21, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14888929 |
Nov 3, 2015 |
10006874 |
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PCT/US2014/036681 |
May 2, 2014 |
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15985389 |
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61854894 |
May 3, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B07C 5/34 20130101; C10L
5/48 20130101; G01N 23/222 20130101; C10L 2290/60 20130101; C10L
2290/24 20130101; G01T 3/00 20130101 |
International
Class: |
G01N 23/222 20060101
G01N023/222; C10L 5/48 20060101 C10L005/48; G01T 3/00 20060101
G01T003/00; B07C 5/34 20060101 B07C005/34; G01N 23/12 20060101
G01N023/12 |
Claims
1. A process of sorting alternative fuel materials into two or more
locations using an on-line nuclear based analyzer, the process
comprising: conveying the alternative fuel materials to the on-line
nuclear based analyzer; quantitatively and non-destructively
measuring an elemental composition of the alternative fuel
materials including hydrogen, carbon, and oxygen using the online
nuclear based analyzer; determining a calorific value of the
alternative fuel materials based at least on the measured elemental
composition; directing the alternative fuel materials with the
calorific value within a first range to a first location; and
directing the alternative fuels material with the calorific value
within a second range to a second location.
2. The process of claim 1, wherein quantitatively and
non-destructively measuring the elemental composition of the
alternative fuels materials includes conveying the alternative fuel
materials through the on-line nuclear based analyzer on a conveyor
with at least one neutron source located below the conveyor and
detecting gamma rays emitted from the alternative fuel materials
with at least one detector located adjacent the conveyor.
3. The process of claim 2, wherein quantitatively and
non-destructively measuring the elemental composition of the
alternative fuels material includes detecting gamma rays emitted
from the alternative fuel materials with an array of detectors
located on the side of the conveyor.
4. The process of claim 2, wherein quantitatively and
non-destructively measuring the elemental composition of the
alternative fuels material includes detecting gamma rays emitted
from the alternative fuel materials with an array of detectors
located on each side of the conveyor.
5. The process of claim 4, wherein quantitatively and
non-destructively measuring the elemental composition of the
alternative fuels material includes detecting gamma rays emitted
from the alternative fuel materials with an additional array of
detectors located above the conveyor.
6. The process of claim 4, wherein conveying the alternative fuel
materials through the on-line nuclear based analyzer on a conveyor
including sidewalls of fifty or more degrees inclination to
horizontal forming a substantially rectangular shape and
positioning the detector arrays along the sidewalls.
7. The process of claim 1, further comprising blending the
alternative fuel materials from the first location with the
alternative fuel materials from the second location to obtain a
material with a predetermined calorific value.
8. The process of claim 1, wherein quantitatively and
non-destructively measuring the elemental composition of the
alternative fuels materials includes detecting trace amounts of
contaminants.
9. An analyzer for measuring an elemental composition of materials,
the analyzer comprising: a conveying mechanism including a conveyor
extending in a horizontal direction, a first side wall extending
adjacent the conveyor, and a second side wall extending adjacent
the conveyor opposite the first side wall forming a detection zone;
at least one neutron source located proximate the detection zone;
and at least one detector located proximate the detection zone and
on a side of the detection zone adjacent the neutron source.
10. The analyzer of claim 9, further comprising a first array of
detectors proximate the first side wall including the at least one
detector, and a second array of detectors proximate the second side
wall; wherein the first array of detectors and the second array of
detectors are configured to detect trace amounts of elements
including contaminants.
11. The analyzer of claim 10, further comprising an array of
neutron sources including the at least one neutron source located
proximate the conveyor.
12. The analyzer of claim 9, wherein the first side wall and the
second side wall are angled substantially perpendicular to the
conveyor forming a rectangular detection zone.
13. The analyzer of claim 9, wherein the first side wall and the
second side wall are angled from 50 degrees to 130 degrees relative
to the conveyor.
14. The analyzer of claim 9, wherein the at least one neutron
source is configured to emit fast neutrons, thermal neutrons, or a
combination of both.
15. The analyzer of claim 9, further comprising a processing module
configured to determine a calorific value of alternative fuel
materials based at least on the elemental composition measured by
the at least one detector.
16. A process of analyzing bulk materials using an on-line nuclear
based analyzer including at least one neutron source and at least
one detector, the process comprising: conveying the bulk materials
to the on-line analyzer; conveying the bulk materials through the
on-line analyzer on a conveying mechanism including a conveyor
extending in a horizontal direction, a first side wall adjacent the
conveyor and a second side wall adjacent the conveyor forming a
detection zone; directing neutrons at the bulk materials using the
at least one neutron source located proximate the detection zone;
and quantitatively and non-destructively measuring an elemental
composition of the bulk materials using the at least one detector
located proximate the detection zone and located on an adjacent
side of the detection zone.
17. The process of claim 16, wherein the process includes detecting
trace amounts of amounts of materials within the bulk materials
using the array of detectors.
18. The process of claim 17, wherein quantitatively and
non-destructively measuring an elemental composition of the bulk
materials and detecting trace amounts of amounts of materials
within the bulk materials also uses a second array of detectors
located proximate the second side wall.
19. The process of claim 17, wherein directing neutrons at the bulk
materials also uses an array of neutron sources located proximate
the conveyor.
20. The process of claim 17, further comprising: directing the bulk
materials to a first location when trace materials of contaminants
above a predetermined level is detected; and directing the bulk
material to a second location when trace materials of contaminants
below the predetermined level is detected.
21. The process of claim 20, further comprising blending the bulk
material from the first location with the bulk material from the
second location to include an amount of contaminants below a second
predetermined level.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to in-line
analyzers, and is directed to an in-line analyzer for alternative
fuels.
BACKGROUND
[0002] In line Prompt Gamma Neutron Activation Analysis (PGNAA)
analyzers are in wide use throughout the coal, cement, and minerals
industries. These systems are used for measuring bulk material,
such as rock material coming out of a mine. They do not just do a
surface measurement such as X-ray fluorescence and X-ray
diffraction, but the analysis is deeply penetrating, and can thus
analyze large quantities of materials. The most prevalent type of
PGNAA analyzer is an on-belt conveyor analyzer, where all of the
material on the conveyor belt is analyzed.
[0003] A commercially successful PGNAA analyzer was a chute-type of
analyzer, as shown in FIG. 1 and described in 1986 U.S. Pat. No.
4,582,992 to Atwell et al. titled "Self Contained, On-line,
Real-Time Bulk Material Analyzer." Coal or rock produce was sent
down the chute, and the material passing through the system was
analyzed by the system. U.S. Pat. No. 4,582,992 describes that the
PGNAA system was self-contained. These chute systems were very
expensive and installation was very costly and difficult. This
problem was solved with the development of on-line conveyor-belt
PGNAA analyzers. One cross-belt analyzer is shown in FIGS. 2A and
2B, and described in 1995 U.S. Pat. No. 5,396,071 to Atwell et al.
titled "Modularized Assembly for Bulk Material Analyzer". These
cross-belt systems were significantly easier to install, and fit
very well into the factory operations.
[0004] Since the first cross belt was developed, there have been a
number of innovations to these cross-belt systems. The innovations
have mainly focused on making the system easier to install and
manufacture. For example, in U.S. Pat. No. 5,396,071 the belt
analyzer was built in multiple identical segments. Segments on the
bottom were made from the same mould, and segments on the top were
made from a different mould. The central mould was modified to hold
the source and detector. Thus this innovation focused on making it
easier to build and assemble the analyzer. In Dec. 5, 2000 U.S.
Pat. No. 6,157,034 to Griebel et al. titled "Flexible
multiple-purpose modular assembly for a family of PGNAA bulk
material analyzers," side modules are used on the conveyor belt
analyzer such that the analyzer can be easily configured for
different sizes of conveyor belts. This innovation again made it
easier for installation and adjustment for different belt sizes,
and it simplified manufacturing. In 2002, U.S. Pat. No. 6,657,189
to Atwell et al. titled "Maintaining Measurement Accuracy with
Prompt Gamma Neutron Activation Analysis with Variable Material
Flow Rates or Material Bed Depths," the system was designed to
algorithmically correct for errors as a result of bed depth and
flow rates. This patent was focused on reducing the error that
varying flow rates and belt loading can cause in the PGNAA
measurement. In W.O. Patent Application No. 2003056317 to Edwards
et al. titled "Bulk Material Analyzer and Method of Assembly"
discloses a system consisting of detectors and source into a C
shape such that the system can slide from the side onto the
conveyor belt, and then the other side is added. The main purpose
of this design was for ease of installation, and also for simpler
manufacturing of the analyzer.
[0005] In W.O. Patent Application No. 2008/021228 A3 to Atwell et
al. titled "Bulk Material Assembly Including Structural Beams
Containing Radiation shielding Material" focuses on making the
system easier and less expensive to build, assemble and install.
This patent application describes using structural beams that are
filled with shielding material to make it faster and easier to
install the analyzer, and also reduce the system cost. Thus the
design benefit was for easier installation and reduced costs.
[0006] Aug. 31, 2010 U.S. Pat. No. 7,786,439 to Harris et al.
titled "Detector Apparatus," discloses the idea of putting the
multi-channel analyzer and the detector in a housing that includes
a temperature controlled assembly. U.S. Pat. No. 7,778,783 to
Lingren et al. titled "Method and apparatus for analysis of
elements in bulk substance" discloses a method of stabilizing the
spectra coming from the PGNAA analyzer.
[0007] Since the development of the first PGNAA on-belt analyzers,
the designs have evolved, mainly with the focus of ease of
installation and ease of manufacture. Modern PGNAA devices
typically mount to the rails of a conveyor belt, do not require
cutting of the conveyor belt, and can be installed and calibrated
in a few days.
[0008] The performance of PGNAA analyzers has not improved
dramatically over the 25 years since the systems were first
commercialized, as the systems deliver adequate performance for
process control for most applications.
[0009] The industry with the widest adoption of PGNAA is the cement
industry, where the equipment is used to monitor and control the
raw material used to make cement.
[0010] In the cement industry, there is growing demand for reducing
energy costs by increasing the use of alternative fuels.
Alternative fuels are materials that can be burned in the cement
kiln to provide heat content, and is a replacement for coal and
oil. Alternative fuels are byproducts from industrial or commercial
operations and include paint, metal cleaning fluids, electronic
industry solvents, tires, fly ash, rice hulls, plastics and other
industrial or municipal waste. Typically cement plants can obtain
these items at little or no cost, or in some cases are paid to
burn.
[0011] For a cement plant to burn Alternative Fuels (AF), the AF
generally includes three characteristics. The first characteristic
is that the AF includes little to no elements that negatively
impact the cement manufacturing process. For example, alternative
fuels with too high a level of chlorine are generally unacceptable
for cement plant operations. The Chlorine can turn into
hydrochloric acid, and cause erosion in the kiln. Thus each AF end
user has an upper limit specification on the amount of Chlorine.
The second characteristic is that the AF must have a meaningful
heat value, such that it is useful as a fuel. The third
characteristic is that the material of the AF complies with
environmental regulations. The U.S. regulations essentially state
that to be acceptable, the AF cannot have contaminant levels
greater than coal. This means that for AF to be acceptable for
cement plants, elements such as mercury, arsenic, cadmium, lead,
and other hazardous elements must be at a level that is at or below
the level of coal.
[0012] Currently it is very expensive and time consuming in order
to test and qualify new types of alternative fuels. There are
companies that specialize in blending alternative fuel for cement
plants. The vast majority of these get a very specific and
consistent type of feedstock, and they do not work with multiple
different materials. Only a very few companies blend varying stock
of AF because of the difficulties and challenges in ensuring that
the material is suitable for plant operations.
[0013] Another factor that makes this issue particularly
challenging is that testing AF for trace elements requires very low
detection levels that may not possible with conventional PGNAA
systems. Thus for receiving a wide variety of alternative fuels, an
expensive lab may be required to analyze the AF. A lab can test
only a very small sample, and thus may not be a valid way of
characterizing the AF.
SUMMARY OF THE DISCLOSURE
[0014] The PGNAA analyzer disclosed herein may deliver a
significantly higher performance than conventional PGNAA analyzers
and is designed to deliver performance suitable for analyzing
alternative fuels for major mineral content that ultimately blends
with the quarry rock and sand mineral content cement plants use
such as Si, Al, Fe, Ca, Mg, S, K, Na, Mn, Ti, P--most as oxides)
and detecting and measuring trace contaminants. Further, in
embodiments disclosed herein, the PGNAA measurement information may
be used to prepare a blend of AF with an elemental composition that
is acceptable for plant operations. Additionally, the measurement
data provided by the analyzer may be used to prepare the AF to
specific target heat content (such as BTLU/lb).
[0015] Conventional PGNAA systems may not be capable of measuring
to the detection level required to accurately measure trace
elements in a material. The PGNAA analyzer disclosed herein
includes a geometry that may increase the signal and performance of
PGNAA systems, such as the system shown in FIG. 6. In embodiments,
the PGNAA analyzer includes a flat bottom belt with vertical
sidewalls that may deliver a higher efficiency than a conventional
PGNAA analyzer because it may provide an optimum geometry to locate
arrays of detectors on all sides of the material. The PGNAA
analyzer geometry may include a portion of the source side when
adequate neutron shielding placed between the source and the
detectors on each side of the source. This geometry may not be a
good fit for the type of conveyor belts common to the cement, coal
and minerals industries, because these are `trough-shaped belts
with 20 to 45 degree angles.
[0016] In embodiments, the PGNAA analyzer disclosed herein includes
modern high speed electronics, which combined with this new
geometry can improve the measurement performance of PGNAA by a
factor of 5 to 10.times. or more. The exact performance improvement
depends on other factors such as the density of the material, the
elemental composition of the material (e.g., the percentage of
hydrogen generally boosts the signal from all other elements due to
hydrogen's strong moderation effect on the source neutrons), and so
forth.
[0017] The PGNAA analyzer including modern high speed electronics
may be able to measure down to trace levels for such things as
Mercury. Arsenic, Cadmium, and other trace elements.
[0018] The system with this or a similar geometry can also be used
to analyze raw material, coal, minerals, and other bulk material
with significantly higher performance than conventional PGNAA
systems. So this invention is not limited to AF but to waste and
any material put in or through the system.
[0019] In embodiments, this new high performance analyzer can be
used in a blending process to blend AF so that it meets target
composition. These embodiments include a method of blending the AF
to meet target specifications such as target composition and heat
content (BTU/lb) so that it can be suitable replacement for coal,
oil, and other fuels. This design is made to prepare the AF for the
cement market, but the fuel can be used in any market that can
benefit from replacing coal, oil, and other fuels and for blending
material to meet specific material properties.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a perspective view of a chute analyzer.
[0021] FIG. 2A is a perspective view of a conveyor belt
analyzer.
[0022] FIG. 2B is a side view of a conveyor belt analyzer.
[0023] FIG. 3 is a diagram of an analyzer where the material flows
thorough the analyzer. This configuration may be used for a static
analyzer, or a slurry analyzer.
[0024] FIG. 4 is a schematic illustration showing conventional
conveyor belt analyzer.
[0025] FIG. 5 is a schematic illustration showing another
conventional conveyor belt analyzer.
[0026] FIG. 6 is a schematic illustration of one embodiment of a
high performance analyzer.
[0027] FIG. 7 is a schematic illustration of an alternate
embodiment of the high performance analyzer of FIG. 6.
[0028] FIG. 8A is a schematic illustration of an alternate
embodiment of the high performance analyzer of FIGS. 6 and 7.
[0029] FIG. 8B is a schematic illustration of an alternate
embodiment of the high performance analyzer of FIGS. 6 and 7.
[0030] FIG. 8C is a schematic illustration of an alternate
embodiment of the high performance analyzer.
[0031] FIG. 9 is a schematic illustration of a system for
shredding, analyzing and blending alternative fuels.
[0032] FIG. 10 provides additional configurations for preparing
alternative fuels.
[0033] FIG. 11 is a schematic illustration of a blending
system.
[0034] FIG. 12 is a perspective view of a high performance PGNAA
analyzer.
[0035] FIG. 13 is a functional block diagram of an analyzing
system.
[0036] FIG. 14 is a functional block diagram of an analyzing system
where the material is transported in a pipe.
[0037] FIG. 15 is a functional block diagram of an analyzing system
where the material is transported in a air-slide.
DETAILED DESCRIPTION OF THE DRAWINGS
[0038] There have been several different types of PGNAA analyzers
that have been developed over the past 25 years. These include a
chute analyzer shown in FIG. 1, a conveyor analyzer, shown in FIG.
2, and a pipe analyzer where the material is analyzed either when
it is not moving or when it is passing through the system, as shown
in FIG. 3. These systems take bulk material in solid or liquid
form, and analyze the material. These systems and in particular the
conveyor belt analyzer are used in the coal, cement, and minerals
industries.
[0039] By far the most predominant type of PGNAA analyzer is an
on-belt conveyor analyzer, where the material is transported on a
conveyor belt. A conveyor belt analyzer is shown in FIG. 4, where
the neutron source 404 is on the bottom, the belt 401 holds the
material 402, and the detectors 403 are located above the material
402. This is a typical geometry for a cement analyzer. Another
configuration, shown in FIG. 5 is where the conveyor belt is the
same, but the neutron source is on the top above the material, and
the detectors are below the belt. This is a common configuration
for coal PGNAA analyzers. In a conveyor system, the conveyor belt
is typically held in place using toughing belt idler assemblies.
The vast majority of toughing belt idler assemblies that hold the
conveyor belt result in an angle 405 that is at a maximum of 45
degrees.
[0040] FIG. 6 is a schematic illustration of one embodiment of a
high performance analyzer 100. In the embodiment illustrated, the
PGNAA analyzer 100 includes a conveying mechanism 108. The
conveying mechanism 108 includes a conveyor 101 with a flat bottom
belt. The conveying mechanism 108 may also include sidewalls 107
adjacent conveyor 101 extending at least partially in the vertical
direction. The Conveyor 101 and the sidewalls 107 may form a
detection zone 109. This detection zone is the area that the
material travels where the material is analyzed.
[0041] In some embodiments, the conveying mechanism may be
rectangular shaped as show in FIG. 6 and may include substantially
vertical sides 107. In other embodiments, the conveying mechanism
108 may be trough shaped with the sides 107 angled greater than 50
degrees from the horizontal and up to 130 degrees relative to the
conveyor 101. In another embodiment, the sides 107 are angled from
40 degrees to 130 degrees relative to the conveyor 101. In another
embodiment, the sides 107 are angled from 90 degrees to 120 degrees
relative to the conveyor 101. In still a further embodiment, the
sides 107 are angled from 90 degrees to 120 degrees relative to the
conveyor 101.
[0042] The analyzer 100, as shown in the preferred embodiment in
FIG. 6, and alternate embodiments in FIG. 7, FIGS. 8A, 8B, and 8C
include locating at least one neutron source 104 proximate the
detection zone 109. In the embodiment illustrated in FIG. 6, the
neutron source 104 is proximate the conveyor 101 and below the
conveyor 101. In the embodiment illustrated in FIG. 7, the neutron
source is located above the detection zone 107, opposite the
conveyor 101. In the embodiment in FIG. 8C, the neutron source is
located on the side of the conveyor, proximate the detection zone
109, and the conveyor 101 acts as part of the sidewall of the
analyzer 100.
[0043] As illustrated in FIG. 6, the detectors 103 are positioned
proximate the detection zone 109 along a side of the detection zone
109 adjacent the location of the neutron source 104.
[0044] Detectors 103 may be positioned on one side, or both sides
of the side walls 107. As illustrated in FIGS. 7, 8A, and 8C,
detectors 103 can additionally be positioned opposite the neutron
source 104 for additional signal. As illustrated in FIG. 7, the
neutron source 104 may be above the material being analyzed. An
alternate embodiment as illustrated in FIG. 8C is to place the
source to the side of the material being analyzed. One or multiple
detectors 103 can be used to increase the overall signal from the
analyzer 100. The detectors 103 can be horizontal to the belt as
shown in FIG. 6, or vertical, or any orientation on the sides,
which may increase the geometric efficiency of the PGNAA system.
Arrays 105 of detectors 103 may also be used in the various
locations for detectors described herein. In some embodiments, the
analyzer 100 may also include an array of neutron sources 104.
[0045] The analyzer 100 may also include a controller 110. The
controller 110 may be configured to receive the signals from the
detectors 103 and may be configured to process the signals received
to determine the composition of bulk material, such as an
alternative fuel source and to determine the amount of trace
elements, such as contaminants that are within the composition. The
controller 110 may also be configured to sort the bulk material
based on its composition by directing the bulk material to two or
more locations based on the composition of the bulk material, such
as by directing a diverter gate into various positions to divert
the bulk material into different directions. The controller 110 may
also be configured to determine the calorific value of the bulk
material, such as alternative fuel sources based on the measured
composition of the bulk material.
[0046] The configurations disclosed herein may situate the
detectors 103 closer to the material that emits the gamma rays
after the neutron source 104 emits the neutrons into the material,
which may improve the signal. In embodiments, the source may be
partially in the material. The exact location that is optimum may
depend on the material, and the constraints of the system.
[0047] In our preferred embodiment, the belt is flat or close to
being flat with substantially vertical sides. In an alternate
embodiment, the conveyor belt system includes sides that are
gradually rolled vertically to form a tube. A circular array of
detectors can be placed around the belt. The sides, such as the
vertical or gradually rolled sides, can be made of different
materials, but in the preferred embodiment they are made of a
material that can absorb and reflect the neutrons, such as
polyethylene.
[0048] Note that the sides do not have to be perfectly vertical,
and the bottom belt does not have to be perfectly horizontal.
Unlike other on-belt analyzers that have the detectors on the top
or the bottom, with this design the detectors are on the side of
the material under analysis. The detectors located on the
substantially vertical sides of the belt may place the detectors
and source closer to the analysis region, while still allowing for
use of a conveyor mechanism.
[0049] There are other aspects to the design that are common to
PGNAA systems. For example, the detectors are generally shielded
from neutrons entering the detector. A combination of polyethylene,
boron, and other materials may be used to shield the detectors from
the neutrons. The system may include biological shielding for
radiation safety. The neutron source, if an isotope, typically has
bismuth to block gamma rays emitted from the isotopic source. When
a D-T generator is used, additional shielding material may be
required for biological shielding, as well as to shield the
detectors.
[0050] A typical analysis approach is shown in FIG. 13. In the
preferred embodiment, the gamma ray spectra from each gamma
detector is captured by a Analog-to-digital board, and this data is
analyzed by a processing module of the controller 110. In the
embodiment illustrated in FIG. 13, the controller 110 is a
computer. However there are many combinations of detector gamma ray
processing configurations that are acceptable. The resulting
analysis can be displayed on a monitor, or provided over the web.
The computer would typically communicate with some other equipment
as part of this process. For example, a belt scale may be used to
send the weight information to the analyzer, and this would be used
in the analysis. Similarly, a moisture meter, or other sensor can
be configured and used with the information. In the case of
blending or screening of material, the computer may interface to
blending software to control and guide the blending process. There
are a number of external sensors that may be configured with the
system, and there may be a number of different devices and systems
that may take the data and information from the system. Typically
the resulting spectral data coming from the detector is analyzed
using library least squares analysis, or multivariate analysis.
However, there are other approaches that are possible such as
comparison of spectra, peak analysis of spectra, chemometrics, or
other ways to extract the elemental information from the gamma
spectra.
[0051] In this document, we refer to PGNAA. However, in our
preferred embodiment, we are using a neutron generator as a source
of neutrons, and Pulsed Fast Thermal Neutron Analysis (PFTNA) so
that that it is possible to extract additional measurement
information such as the carbon, oxygen, and nitrogen measurement
information. PGNAA does not provide these measurements, but PFTNA
does provide these measurements. However, the technology can be
Thermal Neutron Analysis (TNA), PFNA, and PFTNA, or other
variations that are common in the industry. We refer to PGNAA, but
it can be substituted for PFTNA, TNA, PFNA, or other neutron
activation analysis methods. In a preferred embodiment, we are
using a conveyor belt to transport the material. This is because
conveyor belts are a very common method of transporting material.
However, this can include other conveying means, such as a pipe, a
pipe with a square cross section, apron-chain conveyor, an air
slide, or other means of transporting the material. These transport
methods can be configured with a similar geometry for higher
performance. FIG. 14 shows the material being transported through a
pipe 1407. The pipe would typically be of a low cross section
material, such as a zirconium alloy. The detectors 1-3 are shown in
an array, but they can be configured to be closer to the sides of
the pipe 1407. As with other analyzer, there will be shielding
between the neutron source and the detectors. The source can be
pulsed or continuous neutron source. FIG. 15 shows an alternate
embodiment where the conveyor includes an air-slide. In the
embodiment illustrated, the conveyor includes an air chamber 1402
and a porous material 1401 that allows air to pass to the main
transport chamber 1409. The main transport chamber 1409 includes
sides 1403 adjacent the porous material 1401 and a top 1409. Top
1409 may extend from one side 1403 to the other side 1403. Top 1409
is located opposite porous material 1401 relative to the main
transport chamber 1409 and the detection zone 109. The main
transport chamber 1409 encloses around the detection zone 109. The
air chamber 1402 is located next to the main transport chamber 1409
and is separated from the main transport chamber 1409 by the porous
material 1401 The air from the air chamber travels through the
porous material 1401, and fluidizes the material being transported
102. The air slide is angled on a slight angle from horizontal to
convey the material down the air slide. The conveyor/air slide
section in the analyzer may also be made of material that has a low
neutron cross section such as carbon fiber to minimize the signal
from the air chamber structural material. Similarly the porous
material may be composed of a material with a lower cross section
material. The detectors are positioned to optimize the signal in
the detection zone 109. In FIG. 14, and FIG. 15, additional
shielding material and moderation material may be used between the
neutron source and the material and detectors to optimize the
signal from the material 102. As with the conveyor belt solution,
the detectors may be located on the sides and adjacent to the
neutrons source, or in the other configurations and embodiments
possible to those skilled in the art. As there are other methods of
conveying material than conveyor belts, we refer to conveyor as a
means of transporting the material, whether a conveyor belt, pipe,
air slide or other conveying means.
[0052] We are using PFTNA in our preferred embodiment, because this
produces measurements that are not possible with PGNAA. For
example, PFTNA can measure carbon, oxygen, and nitrogen. Using
these and PGNAA measurements, combined with external measurements
such as the moisture or belt loading, the measurements can be used
to estimate the calorific value (one expression is BTU/lb) of the
AF.
[0053] Many different algorithms and equations are possible to
estimate the BTU/lb or similarly to estimate the moisture content
of the material under analysis. The Carbon, Oxygen, and Nitrogen
measurements and other measurements in this equation are provided
by the analyzer, as well as with possible associated additional
measurement equipment combined with this system. An example of how
to estimate the calorific value of the material is to use a linear
combination of elements. This can be in the form of BTU/lb equals
A1*carbon_measurent+A2*oxygen_measurement+A3*hydrogen_measurement+AN*N_Me-
asurement, where A1, A2, A3 coefficients, and AN*N_Measurement
represents other coefficients and measurements that are used to
calculate the calorific value. This is just one example of
calculating the calorific value. Many different equations using the
analyzer measurement values with possibly additional measurements
from other equipment can be used to calculate the heat value. We
refer to heat value and Btu/lb. This refers to the heat content,
often expressed as BTU/lb of the fuel. However, our objective is to
produce a heat value that can be compared to coal or other fuels,
whether this is in lbs, kg, an integrated value, or other methods
or units used to express the heating value of the material.
[0054] Various scenario and use models are possible with this
configuration. It may be possible to just analyze the AF to ensure
and verify that the AF has suitable properties acceptable for use
in a cement plant. Another use model is to use the analyzer to
blend the AF to provide a more consistent fuel.
[0055] Sorting followed by Gravimetric Blending utilizing
individual weigh-feeders on each sorted stockpile that meter out a
precisely controllable mass flow rate that when combined achieves a
target blend. This can be done in many different ways. An example
of a blending system is shown in FIG. 9. A fork lift 901 takes the
alternative fuels and puts the material into a hopper 902. The AF
is then conveyed 904 to a shredder 905. The AF is shredded, and
then conveyed 906 to a coarse shredded pile 907. Magnets to pull
off steel can be used in this process 903, and at other locations.
The AF is then transported, either on a conveyor or by fork lift to
another hopper and conveyed to two-stage shredder 909. Thus the
material comes out triple-shredded. The AF material is then run
through the analyzer 910. This analyzer provides the elemental
information of the triple-shredded Alternative Fuel. The material
then is placed in one or more piles 911 912. The composition of
each pile is known from the measurement from the sensor 910. Thus
these piles can be gravimetrically blended to get a more consistent
product or a pile of unacceptable material can be sorted using a
diverter 913. The diverter 91 may be controlled by the controller
110. If there are any contaminants or unwanted contaminants, a pile
may be unacceptable for use as AF 3. There are several ways to
handle rejected material. The first is to blend small amounts of
rejected material with this with other piles that may have none or
a near-negligible amount of undesired trace minerals, such that the
overall blend is acceptable. The second approach is to have the
pile hauled to a landfill.
[0056] An enhancement of this blending operation is to correct and
adjust the material in the piles so that it has the required
characteristics. For example, it is possible that the closer the
characteristics of the AF is to a customer's requirements, and the
more consistent the fuel, the more valuable the fuel. If a specific
BTU/lb is desirable, then blending can be done such that the AF has
the required BTU/lb. To blend the fuel to a specific BTU content,
AF with known high BTU material may be triple shredded and added to
one pile. Alternatively, a low BTU/lb pile can be made with lower
BTU/lb material. Using the average BTU/lb of each pile, a ratio of
the two materials can be blended to give a specific BTU/lb value. A
specific example can be used to clarify this. Assume one pile is
5000 BTU/lb, and the other pile is 10,000 BTU/lb, then a 50%/50%
blend will result in a pile with a BTU of approximately 7,500
BTU/lb. Another approach is to blend while the material is being
analyzed. For example, assume one pile has a 5,000 BTU/lb average,
and then higher BTU material is run and added to the pile. The
material with the higher BTU/lb is sent through the triple
shredding process, and then the measured BTU information of this
material is mass-integrated with the original pile to build up a
pile to a target BTU level. Using this approach, a pile can be
built that has the required BTU/lb value.
[0057] Yet another approach is to take the shredded alternative
fuel, and placing this in a large layered pile. As a layer is
placed on the pile, the composition of the AF material and location
of the AF material is recorded. Layer after layer of AF are built
up on horizontal layers. If the pile is layered horizontally, then
the AF will be reclaimed/extracted vertically, and thus will
represent an average for the material. Prior to the extraction,
corrective material is added to the pile. For example, if a region
in the pile has a low BTU/lb, then high BTU/lb material is added at
that location. This may be AF, or alternately it may be another
fuel such as coal that is added. The high BTU/lb material is added
to the location with the lower BTU. In this way, the pile is built
up such that it has a composition that is controlled and built to
target specifications. Reclaiming of the pile is done vertically,
effectively averaging or integrating the material such that the
resulting blend is consistent and at target specifications.
[0058] Two other blending approaches are illustrated in FIG. 10. In
the top figure, there are two or more piles of AF. One pile 1007
has high BTU material, while another pile 1008 has lower BTU
material. The material is placed on the conveyor belt or transport
mechanism, either by fork lift in this case, or by other means such
as silos. The material is then conveyed to be shredded. A triple
shredding of the material can be done 1005 to ensure that the AF is
well shredded, and in small pieces to aid in material transport and
to help blending. There are cases where no shredding is required,
but in this example the material is triple shredded, and then put
through the analyzer 910. The material is then placed in a pile
1006. By using the analyzer measurements for feedback, and using
this information to adjust the amount of material 1008 and 1007
that is used, this system can be designed to build a pile that
meets specific target composition. The pile 1006 may be used, or
may be further mixed or blended to further reduce the fuel
variability.
[0059] In the blending example in the bottom of FIG. 10, the
material is taken off the piles, shredded 1005 and run through the
analyzer 910. Some form of diverter gate 913 can be used to build
up different separate piles 911 912, or alternately any material
that has unwanted contaminants can be sorted out 912. This process
would be used in cases where there is the potential of material
that is not acceptable and that needs to be separated from the rest
of the AF.
[0060] The simplest way to use this system is to run the material
through the analyzer, whether it requires shredding or not, and to
place the material in a pile or container. The analysis can then be
used to verify that the material is acceptable for plant
operations, or the measurement information can be used to decide
whether the material is not acceptable.
[0061] The blending of materials does not have to be limited to two
materials, or just to waste or alternative fuels. Many different
additives can be used. FIG. 11 shows a system where there are 7
additives that can be used to blend the material to a final
composition. The material in the silos 1101 to 1107 can be any
material, such as AF, waste, iron, silicon, plastic beads, or other
materials that may be used to blend to pile 1108. The analyzer 905
is used to monitor the composition of the material and allows the
operators to blend to a specific composition and/or heat content of
the pile 1108. This pile in turn may not be the end product, but
may be mixed or blended, or used with other material. This approach
has the benefit of being able to blend the pile to a range of
values that is desirable for the blend pile 1108. This does not
have to be for the cement industry, it can be for any industry that
can benefit from combing the material in a controlled fashion to
product the pile 1008. For producing a fuel, the silos might
include one silo with high BTU/lb AF, and another silo with lower
BTU/lb material, and this is used to control the output blend.
Alternately, low Btu/lb material may be added to the belt before or
after the silos and the material in the silos used to adjust the
mixture. Note that we are using silos in this example, but these
can be piles, or other means of providing the required material. In
addition, when we refer to BTU/lb, it is the heat content of the
material on a weight basis, so can be expressed in many different
methods. As detailed in FIG. 11, the analyzer can be used to blend
material to a specific composition that, in the case where one of
the materials is waste or AF, can be used as a prepared blend that
is suitable for use as a fuel.
[0062] The information from the analyzer does not have to provide
all of the required information for analysis. For example, the belt
loading is typically provided by a separate sensor. The moisture
reading may be provided by an external moisture meter. Alternately,
external sensors can be added that can be used to improve the
analysis results. For example, dual energy gamma detectors can be
used to provide an absolute measurement of the organic and
inorganic material in the AF. This in turn can be used to adjust
the measurement information from the analyzer. In some cases, there
will be readings that are not suitably accurate from the analyzer.
In this case, it may be necessary to use separate measurement
equipment to provide the required data and information. The
analyzer does not have to provide all of the required measurement
information, but the information it provides is used to ensure that
the material is acceptable as a fuel.
[0063] These blending approaches detailed above are not new. Raw
material blending has been done with PGNAA systems for over 20
years, and is in widespread use throughout the cement industry.
Extensive equipment, processes, and blending software is widely
available that helps in the blending process. Any of the blending
approaches that are now used for raw material blending, whether it
is in discrete piles, done in silos, done in layers, or done in
real-time using multiple `sweetners`, can be used to blend the
alternative fuels to specific target blends. In addition, there are
sites that blend AF. These sites use labs to do sample analysis of
the AF to ensure no contaminants and to have an approximate
composition of the AF, and then the AF is mixed together.
[0064] There are many different ways of using the measurement data
to calculate material heat value (expressed as BTU/lb in this
patent). It is possible to use the system measurement data and
associated peripheral data to estimate the AF BTU/lb, and allow
blending to specific BTU targets, or to verify that the material is
acceptable for use as a fuel. Another benefit of this new design of
analyzer is that it is possible to measure trace contaminants, and
greatly improve the performance of these analyzers. Thus this has
other applications such as measuring and controlling Mercury
content of raw materials, measuring trace contaminants in bulk
material, controlling the amount of trace contaminants in bulk
material, blending using the measurement information, sorting using
the measurement information, faster more accurate sorting of coal
with different ash contents, and other applications that benefit
from the improved system performance.
[0065] FIG. 12 is a perspective view of an embodiment of a high
performance PGNAA analyzer 1200. As illustrated in FIG. 12, a
conveying mechanism 1208 may extend through the analyzer 1200. The
conveying mechanism 1208 may include a conveyor 1201 with sides
1207. Sides 1207 may be angled relative to conveyor 1201 as
disclosed herein.
[0066] Those of skill will appreciate that the various illustrative
logical blocks, modules, and algorithm steps described in
connection with the embodiments disclosed herein can be implemented
as electronic hardware, computer software, or combinations of both.
To clearly illustrate this interchangeability of hardware and
software, various illustrative components, blocks, modules, and
steps have been described above generally in terms of their
functionality. Whether such functionality is implemented as
hardware or software depends upon the design constraints imposed on
the overall system. Skilled persons can implement the described
functionality in varying ways for each particular application, but
such implementation decisions should not be interpreted as causing
a departure from the scope of the invention. In addition, the
grouping of functions within a module, block, or step is for ease
of description. Specific functions or steps can be moved from one
module or block without departing from the invention.
[0067] The various illustrative logical blocks and modules
described in connection with the embodiments disclosed herein can
be implemented or performed with a general purpose processor, a
digital signal processor (DSP), application specific integrated
circuit (ASIC), a field programmable gate array (FPGA) or other
programmable logic device, discrete gate or transistor logic,
discrete hardware components, or any combination thereof designed
to perform the functions described herein. A general-purpose
processor can be a microprocessor, but in the alternative, the
processor can be any processor, controller, microcontroller, or
state machine. A processor can also be implemented as a combination
of computing devices, for example, a combination of a DSP and a
microprocessor, a plurality of microprocessors, one or more
microprocessors in conjunction with a DSP core, or any other such
configuration.
[0068] The steps of a method or algorithm described in connection
with the embodiments disclosed herein can be embodied directly in
hardware, in a software module executed by a processor (e.g., of a
computer), or in a combination of the two. A software module can
reside in RAM memory, flash memory, ROM memory, EPROM memory,
EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or
any other form of storage medium. An exemplary storage medium can
be coupled to the processor such that the processor can read
information from, and write information to, the storage medium. In
the alternative, the storage medium can be integral to the
processor. The processor and the storage medium can reside in an
ASIC.
[0069] The above description of the disclosed embodiments is
provided to enable any person skilled in the art to make or use the
invention. Various modifications to the embodiments of the analyzer
will be readily apparent to those skilled in the art, and the
generic principles described herein can be applied to other
embodiments without departing from the spirit or scope of the
invention. Thus, it is to be understood that the description and
drawings presented herein represent a presently preferred
embodiment of the analyzer and are therefore representative of the
subject matter which is broadly contemplated by the present
invention. It is further understood that the scope of the present
invention fully encompasses other embodiments that may become
obvious to those skilled in the art.
* * * * *