Automatic on-line chemistry monitoring system having improved calibration unit

A system for automatically sampling, monitoring and analyzing power plant steam cycle water supplied from various points in a power plant steam cycle system as a plurality of influent fluid sample streams. Plural continuous monitor modules each include continuous on-line monitors and provide continuous on-line monitoring of a corresponding influent fluid sample stream, and an ion chromatograph unit provides semi-continuous monitoring of a selected one of the influent fluid sample streams. Each continuous monitor module also includes an improved calibration unit including a conditioning unit which creates a pressure differential in the influent fluid sample stream and utilizes the pressure differential to inject a mixed standard solution into the influent fluid sample stream, thereby providing a conditioned influent fluid sample stream having predetermined chemical characteristics; the continuous on-line monitors are calibrated with respect to the predetermined chemical characteristics of the corresponding conditioned influent fluid sample stream and the ion chromatograph unit is calibrated with respect to the predetermined chemical characteristics of the selected conditioned influent fluid sample stream supplied thereto. A control unit receives signals representative of the monitored chemical characteristics from the continuous on-line monitors and the ion chromatograph unit and uses these signals in a feedback loop to control the monitoring system, to automatically calibrate the continuous on-line monitors and the ion chromatograph unit in accordance with the predetermined chemical characteristics of the conditioned influent fluid sample streams, and to detect, analyze and correct steam cycle water chemistry changes before corrosion or other problems related to water chemistry imbalances.

CROSS REFERENCES TO RELATED APPLICATIONS 
The present application is related to copending patent application Ser. No. 
793,061, filed Oct. 30, 1985, for AUTOMATIC ON-LINE CHEMISTRY MONITORING 
SYSTEM, by Byers, Carlson, Wooten, Richards and Pensenstadler, assigned to 
the assignee of the present application, and co-pending patent application 
Ser. No. 782,858, filed Oct. 2, 1985, for ON-LINE CALIBRATION SYSTEM FOR 
CHEMICAL MONITORS, also assigned to the assignee of the present 
application. 
BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention generally relates to a system for automatically 
sampling, monitoring and analyzing power plant steam cycle water from a 
plurality of points in a power plant steam system and, more particularly, 
to a system for performing continuous on-line chemical monitoring using 
continuous on-line monitors, and semi-continuous on-line monitoring using 
an ion chromotograph unit, for controlling the monitoring with real-time 
feedback from the continuous on-line monitors and the ion chromatograph 
unit, for automatically analyzing the monitored chemical characteristics, 
and for automatically calibrating the continuous on-line monitors and the 
ion chromatograph unit with an improved autocalibration unit. 
2. Description of the Related Art 
The control of impurities in power plant steam cycle water is recognized as 
being essential to the protection of a power plant's steam system against 
corrosion related failures. In spite of advances in methods for detecting 
and measuring impurities, or contaminants, at ultra-trace concentration 
levels, plant chemistry monitoring is, for the most part, based on the 
on-line monitoring of only a few chemical characteristics, such as 
conductivity, pH, and dissolved oxygen concentration. Many critical 
impurities which cause corrosion, such as chloride and sulfate, are 
checked only once or twice a day by laboratory analysis of grab samples. 
Grab sample data, since obtained only at long intervals, provides only an 
historical record of plant chemistry and is of little use in controlling 
the levels of corrosion causing impurities and thus in the prevention of 
corrosion related failures. Furthermore, on-line monitor information which 
is available, is provided only as strip chart records which require 
tedious operator analysis. 
In current instrumentation, particularly cation conductivity monitors, the 
composition of the fluid sample, or solution, to be monitored is assumed 
at the time that the instrument is manufactured. The calculation of 
temperature compensated cation conductivity values, however, is dependent 
on the measured cation conductivity and solution composition. Thus, 
temperature compensated cation conductivity values will be erroneous if 
the actual solution composition differs from the assumed composition. The 
lack of real time feedback in prior monitoring systems prevents accurate 
temperature compensation since the actual solution composition cannot be 
factored into the temperature compensation. 
Current monitoring systems also suffer from a lack of integrated 
calibration capability. Calibration is usually a scheduled maintenance 
operation; thus, calibration problems or equipment failures which occur 
between scheduled calibrations could go undetected and uncorrected until 
the next scheduled calibration. Moreover, as a scheduled maintenance 
operation, calibration has usually been performed manually as an off-line 
procedure using standards which may be significantly different than the 
sample, for example, highly concentrated buffer solutions. 
Several systems have been developed to monitor power plant steam cycle 
water. U.S. Pat. No. 4,414,858, Peterson et al., assigned to the Assignee 
of the present application, discloses a system for sampling fluids with a 
plurality of fluid sample lines connected to various points in a power 
plant steam system. A valve arrangement connects a selected fluid sample 
line to an analyzer, and passes the non-selected fluid samples to a common 
drain line which is connected back to the power plant steam system. A 
microprocessor controls the valve arrangement in accordance with a set of 
stored instructions to selectively connect each of the sample fluid lines 
to the analyzer in a sampling sequence, and controls the analyzer with 
open loop control. Each fluid sample line also includes a sensor which 
provides an output signal to the microprocessor, which alters the sampling 
sequence if a particular sensor output indicates an alarm condition. This 
system provides only one on-line monitor per sample stream, and thus 
monitors one chemical characteristic of each sample fluid stream. Further, 
calibration of the sensors and the analyzer is performed manually in an 
off-line procedure. 
Another system for monitoring steam producing water is disclosed in U.S. 
Pat. No. 4,472,354, Passell et al. This system uses ion chromatographic 
analysis to provide an ion profile of the steam producing water. Plural 
sampling systems collect the steam producing water supplied from a 
multiple number of points in a power plant steam system over a five to 
six-hour time period, called a fill cycle. At the end of the fill cycle, 
the water collected in a particular sampling system is supplied to the ion 
chromatographs. Thus, the system does not provide for continuous on-line 
monitoring of the steam producing water at each point in the plant 
steam/water cycle, but rather a periodic monitoring of a fluid sample 
collected over a five to six hour period to provide an ion profile of the 
steam producing water flowing in the plant. This system does not employ 
any continuous on-line monitors, and uses open loop control of the 
operation of the ion chromatographs. In this system, calibration is 
performed by diluting a standard solution with pure water and providing 
the diluted solution directly to the ion chromatographs in response to an 
operator decision. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, there is provided a system for 
automatic continuous on-line monitoring of the water chemistry of each of 
a plurality of influent fluid sample streams from various points in a 
power plant steam system. The monitoring system of the present invention 
combines analytical instruments and monitors with computerized control and 
data logging. More particularly, a plurality of continuous monitor modules 
each include continuous on-line monitors for continuous on-line monitoring 
of a respective one of the influent fluid sample streams and and an 
improved calibration unit for selectively producing a conditioned influent 
fluid sample stream having predetermined chemical characteristics against 
which the continuous on-line monitors may be calibrated, and an ion 
chromatograph unit provides semi-continuous monitoring of species for 
which no simple on-line monitor is available in a selected one of the 
influent fluid sample streams. The ion chromatograph unit may be 
calibrated with respect to the predetermined chemical chracteristics of 
one of the conditioned influent fluid sample streams. 
In accordance with the present invention, an improved calibration unit 
includes a conditioning unit which creates a pressure differential in the 
influent fluid sample stream and utilizes the pressure differential to 
inject a mixed standard solution into the influent fluid sample stream, 
thereby providing the conditioned influent fluid sample stream. The use of 
fluid dynamics, the pressure differential, provides a self-regulating unit 
that maintains a precise ratio of mixed standard solution to the influent 
fluid sample stream regardless of the flow rate or temperature of the 
influent fluid sample stream. This improved calibration unit also 
eliminates the need for a pump to inject the mixed standard solution, 
pumps being subject to drift in the adjustment of the injection rate, 
subject to mechanical failure, and costly. Further, the conditioning unit 
requires no electricity and has no moving parts. Conditioning of the 
influent fluid sample streams is easily automated and provides for on-line 
calibration. Moreover, the use of a conditioned influent fluid sample 
stream allows the continuous on-line monitors and the ion chromatograph 
unit to be calibrated in the range in which monitoring is performed, 
rather than a range dictated by a convenient standard or a highly 
concentrated buffer solution. 
The monitoring system is controlled by a control unit including a 
microcomputer or a minicomputer. The control unit receives signals 
representative of the monitored chemical characteristics from the 
continuous on-line monitors and the ion chromatograph unit, and uses these 
signals in a feedback loop to detect monitor failures, to determine the 
sequence in which the plural influent fluid sample streams are supplied to 
the ion chromatograph unit, to control operation of the ion chromatograph 
unit, and to automatically calibrate the contnuous on-line monitors and 
the ion chromatograph unit. The control unit also logs data from the 
continuous monitor modules and the ion chromatograph unit, and interfaces 
with a plant data center. Thus, steam cycle water chemistry changes can be 
detected, diagnosed, and corrected before corrosion or other problems 
related to water chemistry imbalances can occur. 
In the monitoring system of the present invention each continuous monitor 
module monitors the temperature of and performs preliminary processing of 
the corresponding influent fluid sample stream. The preliminary processing 
includes, for example providing the influent fluid sample stream with a 
predetermined volumetric flow rate, deionizing the influent fluid sample 
stream, and the above-mentioned conditioning to perform calibration. Then, 
the continuous monitor module divides each influent fluid sample stream 
into first and second influent fluid sample streams. The continuous 
on-line monitors, in the continuous monitor module, monitors selected 
chemical characteristics of the first influent fluid sample stream, and 
temperature and continuous monitor signals, representative of the 
monitored temperature and chemical characteristics, are generated. The 
second influent fluid sample streams provided by the continuous monitor 
modules are further divided into third and fourth influent fluid sample 
streams and a plurality of cation conductivity monitors monitor the cation 
conductivity of each of the third influent fluid sample streams and 
generate cation conductivity signals representative of the monitored 
cation conductivity. Further, each cation conductivity monitor provides an 
altered, third fluid sample stream from which cations have been removed. 
Each of the plural, altered third and the corresponding fourth influent 
fluid sample streams are selectively supplied to the ion chromatograph 
unit in individual succession, in accordance with a predetermined sampling 
sequence. The ion chromatograph unit performs chromatographic monitoring 
of selected chemical characteristics, in accordance with chromatograph 
actuation signals, and generates chromatograph signals representative of 
the monitored chemical characteristics. The control unit receives the 
temperature, continuous monitor, cation conductivity, and chromatograph 
signals, determines the sampling sequence and interrupts the sampling 
sequence in response to an abnormal one of the output signals, stores 
predetermined conductivity equations and data, and performs a variety of 
analytical functions to control the operation of the monitoring system 
with a feedback loop. The functions performed by the control unit include, 
for example: calculating a strong acid temperature compensated cation 
conductivity in accordance with predetermined conductivity equations, the 
monitored temperature, and the chemical characteristics monitored by the 
ion chromatograph unit; comparing the strong acid temperature compensated 
cation conductivity with the monitored cation conductivity to select the 
chemical characteristics to be monitored by the ion chromatograph unit; 
generating the chromatograph actuation signals in accordance with the 
chemical characteristics selected by comparing the temperature compensated 
cation conductivity with the monitored cation conductivity; calculating a 
cation conductivity including organic acids at the monitored temperature; 
comparing the monitored temperature cation conductivity including organic 
acids with the monitored cation conductivity to determine if calibration 
is required; selectively generating the calibration actuation signals at 
predetermined time intervals and between the predetermined time intervals; 
and calibrating the continuous monitor, cation conductivity and 
chromatograph signals with respect to the predetermined chemical 
characteristics of the conditioned influent fluid sample stream. 
One embodiment of a continuous monitor module comprises a continuous 
monitor unit including continuous on-line monitors for monitoring chemical 
characteristics selected from the group of sodium, dissolved oxygen, 
hydrazine, ammonia, pH, and specific conductivity. 
One embodiment of the ion chromatograph unit comprises an anion 
chromatograph for monitoring anions, an organic acid chromatograph for 
monitoring organic acids, and a cation chromatograph for monitoring 
cations, each of said anion, organic acid and cation chromatographs having 
a sample volume control unit for preparing a sample volume of an influent 
fluid sample stream for monitoring in accordance with corresponding anion, 
organic acid, and cation chromatograph sample volume control unit 
actuation signals. For this embodiment of the ion chromatograph unit, the 
control unit calculates a sample volume of the altered, third fluid sample 
stream to be prepared for monitoring by the anion and organic acid 
chromatograph sample volume control units in accordance with the monitored 
cation conductivity of the altered, third fluid sample stream being 
supplied to the ion chromatograph means and generates the anion and 
organic acid chromatograph sample volume actuation signals based on the 
calculated sample volume of the third influent fluid sample stream, and 
calculates a sample volume of the fourth influent fluid sample stream to 
be prepared for monitoring by the cation chromatograph sample volume 
control unit in accordance with the monitored specific conductivity of the 
fourth influent fluid sample stream being supplied to the ion 
chromatograph unit and generates the cation chromatograph actuation 
signals based on the calculated sample volume of the fourth influent fluid 
sample stream.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The block diagram of FIG. 1 illustrates the overall monitoring system of 
the present invention. Fluid lines 10, individually designated 10.sub.1, 
10.sub.2 . . . 10.sub.n, supply plural influent fluid sample streams of 
steam cycle water from a plurality of different points in a power plant 
steam system to respective ones of a plurality of continuous monitor 
modules 20, individually designated 20.sub.1, 20.sub.2 . . . 20.sub.n. It 
is to be understood that the system of the present invention may be used 
in any type of steam generating electrical power plant, whether fossil or 
nuclear fueled, and may accommodate any number of sample lines, as is 
deemed desirable. Each continuous monitor module 20 performs preliminary 
processing (described below) of the corresponding influent fluid sample 
stream and then divides the corresponding influent fluid sample stream 
received thereby into first and second influent fluid sample streams; the 
module 20 then analyzes the first influent fluid sample stream and 
thereafter directs same to a drain 22. Further, each of the modules 20 
supplies a second influent fluid sample stream through a second fluid line 
24 to the input 26a of a corresponding one of a plurality of second 
influent fluid sample stream flow-splitters 26, individually designated 
26.sub.1, 26.sub.2 . . . 26.sub.n, which divides same into third and 
fourth influent fluid sample streams (or fractional portions) at its 
outputs 26b and 26c, respectively. Corresponding ones of a plurality of 
third fluid lines 28 and fourth fluid lines 30 are respectively connected 
to the first and second outputs 26b and 26c of the second influent fluid 
sample stream flow-splitters 26. Cation conductivity monitors 32 are 
provided in each third fluid line 28 to monitor the cation conductivity of 
the third influent fluid sample streams and to generate cation 
conductivity signals representative of the monitored cation 
conductivities; the cation conductivity monitors 32 also remove cations 
from the third influent fluid sample stream to produce an altered third 
fluid sample stream. 
A first valve system 34 receives the altered third influent fluid sample 
streams from the cation conductivity monitors 32 at corresponding ones of 
a plurality of inputs 34a, and selectively supplies one of the altered 
third fluid sample streams to a first output 34b thereof and the remaining 
altered third fluid sample streams to the second output 34c thereof. A 
first valve system output line 36 is connected to the first output 34b and 
a drain 22' is connected to a second output 34c. A second valve system 38 
receives the fourth influent fluid sample streams from the second outputs 
26c of the second influent fluid sample stream flow splitters 26 at 
corresponding ones of a plurality of inputs 38a via the fourth fluid lines 
30, and selectively supplies one of the fourth influent fluid sample 
streams to a first output 38b thereof and the remaining fourth influent 
fluid sample streams to a second output 38c thereof. A second valve system 
output line 40 is connected to the first output 38b and a drain 22" is 
connected to the second output 38c. The first and second valve systems 34, 
38 operate to supply one of each of the altered third and fourth influent 
fluid sample streams at first outputs 34b, 38b, respectively, in 
individual succession, in accordance with a predetermined sampling 
sequence and with first and second valve system actuation signals. One 
example of a sampling system for use as the first and second valve systems 
34, 38 is disclosed in U.S. Pat. No. 4,414,858, Peterson et al., assigned 
to the Assignee of the present invention, the disclosure of which is 
hereby incorporated by reference. 
An ion chromatograph unit 42 receives the selected ones of the altered 
third and fourth influent fluid sample streams supplied by the first and 
second valve sytems 34, 38 at respective first and second inputs 42a, 42b 
through the first and second valve system output lines 36, 40. An output 
42c of the ion chromatograph unit 42 is connected to a drain 22'". 
An example of one continuous monitor module 20 is shown in the block 
diagram of FIG. 2. The influent fluid sample stream supplied by the fluid 
line 10 flows through a filter 44, a temperature sensor 45, and a shut off 
valve 46, the temperature sensor 45 sensing the temperature of the 
influent fluid sample stream and generating a temperature signal 
representative of the sensed temperature. The influent fluid sample stream 
then flows to a calibration unit 48, entering the calibration unit 48 at 
an input 48a thereof. The calibration unit 48 includes a flow-splitter 49 
for receiving the influent fluid sample stream at its input 49a and for 
providing first and second portions of the influent fluid sample stream 
and its first and second outputs 49b and 49c, respectively. An on-off 
valve 50 and a two-way valve 51, together with a first parallel fluid line 
52, a second parallel fluid line 53 and an output fluid line 54, are 
selectively operable to establish a first fluid sample stream flow path 
for providing the first portion of the influent fluid sample stream to an 
output 48b of the calibration unit, a second fluid sample stream flow path 
for providing the second portion of the influent fluid sample stream to a 
deionizer 55, a conditioning unit 56, and a ballast 57, thereby providing 
a conditioned, deionized influent fluid sample stream to a flowmeter 60 
and a third fluid sample stream flow path for providing the conditioned, 
deionized fluid sample stream to a drain 61. The deionizer 55 is a 
standard mixed bed deionizer for providing a deionized influent fluid 
sample stream, and the conditioning unit 56 (described below in detail 
with reference to FIG. 6) creates a pressure differential in the influent 
fluid sample stream and utilizes the pressure differential to inject a 
mixed standard solution into the deionized influent fluid sample stream, 
thereby providing a conditioned, deionized influent fluid sample stream 
(hereinafter the "conditioned influent fluid sample stream") having 
predetermined chemical characteristics. The ballast 57 ensures that the 
chemical charcteristics of the conditioned influent fluid sample stream 
are stable. 
The on-off valve 50 has an input 50a and an output 50b, the input 50a being 
interconnected with the first output 49b of the flow-splitter 49 by the 
first parallel fluid line 52, and the output 50b being interconnected with 
the output 48b of the calibration unit 48 by the output fluid line 54. The 
on-off valve 50 is selectively operable to establish open and closed 
positions; the on-off valve 50, in the open position thereof, 
interconnecting the first paralle fluid line 52 and the output fluid line 
54 to establish the first fluid sample stream flow path. The two-way valve 
51 has an input 51a, a first output 51b, and a second output 51c, and is 
selectively operable between first and second positions, the first 
position connecting the input 51a and the first output 51b thereof, and 
the second position connecting the input 51a and the second output 51c 
thereof. The second parallel fluid line 53 has a first portion 53a which 
interconnects the second output 49c of the flow-splitter 49 and an input 
55a of the deionizer 55, a second portion 53b which interconnects an 
output 55b of the deionizer 55 and an input 56a of the conditioning unit 
56, a third portion 53c which interconnects an output 56b of the 
conditioning unit 56 and an input 57a of the ballast 57, and a fourth 
portion 53d which interconnects an output 57b of the ballast 57 with the 
input 51a of the two-way valve 51. The two-way valve, in the first 
position thereof, interconnects the second parallel fluid line 53 with the 
output fluid line 54 and establishes therewith, and with the deionizer 55, 
the conditioning unit 56, and the ballast 57, the second fluid sample 
stream flow path. The two-way valve, in the second position thereof, 
interconnects the second parallel fluid line 53 with the drain 61 and 
establishes therewith, and with the deionizer 55, the conditioning unit 
56, and the ballast 57, the third fluid sample stream flow path. 
The calibration unit 48 further includes an influent fluid sample stream 
flow-splitter 62 for dividing the influent fluid sample stream into first 
and second influent fluid sample streams at its first and second outputs 
62b, 62c, respectively. A first fluid line 64 is connected to the first 
output 62b of the influent fluid sample stream flow-splitter 62 and the 
second fluid sample line 24 is connected to the second output 62c of the 
influent fluid sample stream flow-splitter 62. The calibration unit 48 and 
the filter 44 perform the previously mentioned preliminary processing. 
The preferrred embodiment of the calibration unit 48 includes the deionizer 
55 and the ballast 57; however it is possible to eliminate the deionizer 
55 so that the influent fluid sample stream, rather than a deionized 
influent fluid sample stream, is conditioned, and to eliminate the ballast 
if the conditioning unit provides a conditioned influent fluid sample 
stream having uniform and stable chemical characteristics. Alternative 
embodiments of valve system arrangements for establishing various flow 
paths in the calibration unit so as to selectively provide, as outputs 
thereof, the influent fluid sample stream and a conditioned influent fluid 
sample stream are disclosed in patent application Ser. No. 782,858. 
Each continuous monitor module 20 further comprises a continuous monitor 
unit 66 for continuous on-line monitoring of the first influent fluid 
sample stream The continuous monitor unit 66 in each continuous monitor 
module 20 contains as many chemical monitors, connected in parallel by the 
first fluid line 64, as necessary to analyze the chemical characteristics 
of a specific influent fluid sample stream--the chemical characteristics 
of each influent fluid sample stream being dependent on the particular 
point in the power plant steam cycle from which the influent fluid sample 
stream is taken. Thus, each continuous monitor unit 66 includes various 
continuous on-line monitors, including, for example, a sodium monitor 68, 
a dissolved oxygen monitor 69, a pH monitor 70, a hydrazine monitor 71 an 
ammonia monitor 72, and a specific conductivity monitor 73. The various 
monitors 68-73 comprise corresponding detectors, e.g., sodium detector 78, 
dissolved oxygen detector 79, pH detector 80, hydrazine detector 81, 
ammonia detector 82, and specific conductivity detector 83, and each 
detector 78-83 comprises a flow cell (not shown) and a sensor (not shown) 
provided in the flow cell for monitoring the level of the corresponding 
chemical chracteristic of a fluid sample stream. Each monitor produces an 
output representative of the monitored level of the corresponding chemical 
characteristic, the output being, for example, a visual display or an 
electrical signal. The continuous on-line monitors 68-73 may be standard 
monitors produced by Martek, Orion, Orbisphere, or Leeds & Northrup, for 
example. 
To calibrate the monitors 68-73 in the continuous monitor unit 66, the 
calibration unit 48 establishes the second fluid sample stream flow path 
to provide the conditioned, deionized influent fluid sample stream which 
has known concentrations of selected chemicals and thus predetermined 
chemical characteristics, to the output 48b of the calibration unit 48. 
The second fluid sample stream flow path is established in accordance with 
calibration actuation signals for operating the on-off valve 50 to 
establish the closed position thereof and the two-way valve 51 to 
establish the first position thereof. 
When calibration is not being performed, the calibration unit 48 
establishes the first and third fluid sample stream flowpaths to provide 
the first portion of the influent fluid sample stream to the output 48b of 
the calibration unit for monitoring and to provide the second portion of 
the influent fluid sample stream to the conditioning unit 56 and then to 
the drain 61. It is desirable to maintain a continuous flow through the 
conditioning unit so that the chemical characteristics of the conditioned 
influent fluid sample stream are stabilized, thereby permitting 
calibration to be performed without waiting for the chemical 
characterisics of the conditioned influent fluid sample stream to 
stabilize. If a continuous flow is not maintained, an excess of the mixed 
standard solution may accumulate in a portion of the influent fluid sample 
stream, thereby disturbing the predetermined chemical characteristics of 
the conditioned influent fluid sample stream. 
The conditioned influent fluid sample stream is divided into first and 
second conditioned influent fluid sample streams by the influent fluid 
sample stream flow-splitter 62 and the conditioned first fluid sample 
stream is supplied to each of the monitors 68-73 by the first fluid line 
64. The output of each of the monitors 68-73 is calibrated with respect to 
the predetermined chemical characteristics of the conditioned first 
influent fluid sample stream, as is known in the art, by a control unit 
which is described later. Further, the conditioned second influent fluid 
sample stream provided by one of the continuous monitor modules 20 can be 
used to calibrate the ion chromatograph unit 42. By using a flowing 
conditioned influent fluid sample stream, rather than a stagnant buffer 
solution, to calibrate the monitors 68-73, the monitoring system of the 
present invention calibrates the detectors 78-83 in the same environment 
in which they monitor the chemical characteristics of the influent fluid 
sample stream. An on-line calibration system for chemical monitors is 
disclosed in a copending U.S. patent application Ser. No. 782,858, 
assigned to the Assignee of the present invention. 
The ion chromatograph unit 42 is illustrated in the simplified block 
diagram of FIG. 3. One example of the ion chromatograph unit 42 
contemplated for use in the monitoring system of the present invention is 
a Dionex Model 8000 ion chromatograph. The ion chromatograph unit 42 
comprises, for example, an anion chromatograph 86, an organic acid 
chromatograph 87, a cation chromatograph 88, an anion chromatograph eluant 
supply system 89.sub.1 an organic acid chromatograph eluant supply system 
89.sub.2, and a cation chromatograph eluant supply system 89.sub.3. A 
chromatograph selector valve 90 has an input 90a for receiving one of the 
altered third fluid sample streams from the first input 42a of the ion 
chromatograph unit 42 and first and second outputs 90b and 90c in fluid 
communication with the anion chromatograph 86 and the organic acid 
chromatograph 87, respectively. A chromatograph selector valve actuation 
signal operates the chromatograph selector valve 90 between first and 
second positions, the first position connecting the input 90a and the 
first output 90b thereof, and the second position connecting the input 90a 
and the second output 90c thereof. The chromatograph selector valve 90 is 
ordinarily in the first position to provide the altered third fluid sample 
stream to the anion chromatograph 86, and is selectively actuated to 
connect the input 42a with the organic acid chromatograph 87 only when it 
is determined that organic acid analysis is required, as described below. 
Organic acid chromatography is performed only when necessary since the 
suppressor column in the organic acid chromatograph 87 must be replaced 
relatively often, at a high cost. The cation chromatograph 88 receives one 
of the fourth fluid sample streams from the second input 42b of the ion 
chromatograph unit 42. 
The anion, organic acid and cation chromatographs 86-88, and the anion, 
organic acid and cation chromatograph eluant supply systems 89.sub.1 
-89.sub.3 include substantially similar, corresponding elements, and thus 
only the organic acid chromatograph 87 and the organic acid chromatograph 
eluant supply system 89.sub.2 are illustrated and described in detail. 
The organic acid chromatograph eluant supply system 89.sub.2 comprises 
plural eluant supplies, for example, a pH 3 eluant supply 92 and a pH 4 
eluant supply 93 for storing and supplying pH 3 and pH 4 eluants, 
respectively. An eluant selector valve 94 has first and second inputs 94a, 
94b in fluid communication with respective ones of the eluant supplies 92, 
93, and is actuable, in accordance with an eluant selector valve actuation 
signal, to provide a selected one of the eluants to its output 94c. An 
eluant supply line 95 connects an eluant pump 96 to receive the output of 
the eluant selector valve 94. The eluant pump 96 supplies the selected 
eluant to each of the chromatographs 86-88 at a predetermined volumetric 
rate via the eluant supply line 95, in accordance with an eluant volume 
actuation signal. 
Whereas the organic acid chromatograph eluant supply system 89.sub.2 
supplies plural eluants, the anion and cation chromatograph eluant supply 
systems 89.sub.1, 89.sub.3 only provide a single eluant; thus, the anion 
and cation chromatograph eluant supply systems 89.sub.1, 89.sub.3 do not 
require a selector valve. The eluant supplied to the anion chromatograph 
86 is a mixture of carbonate and bicarbonate and the eluant supplied to 
the cation chromatograph 88 is hydrochloric acid HCl or nitric acid 
HNO.sub.3. 
The organic acid chromatograph unit 87 comprises a sample volume control 
unit 98 which prepares a sample volume of the altered third fluid sample 
stream being supplied to the first input 42a of the ion chromatograph unit 
42 for analysis by the organic acid chromatograph 87. The sample volume 
control unit 98 basically includes first and second parallel fluid lines 
99, 100, an injection loop 101 and a concentrator column 102. Further 
details of the sample volume control unit 98 are illustrated in and 
explained with respect to FIG. 5. The organic acid chromatograph unit 87 
also comprises a chromatograph fluid line 103, which connects a separator 
column 104, a suppressor column 106 and a detector 108 in a fluid series 
circuit. 
An example of the strength of the integrated monitoring system of the 
present invention is the placement of the cation conductivity monitors 32 
ahead of, or upstream from, the ion chromatograph unit 42. Ammonia, which 
is present at relatively high concentrations in most power plant steam 
cycle water, causes problems in the detection of anions by the anion 
chromatograph 86. By supplying the third influent fluid sample streams to 
the cation conductivity montiors 32, which remove cations including 
ammonia from a fluid sample to provide the altered third fluid sample 
stream, prior to supplying one of the third influent fluid sample streams 
to the anion chromatograph 86, ammonia is removed from the third influent 
fluid sample stream before it is supplied to the anion chromatograph 86, 
thereby eliminating this serious problem. 
FIG. 4 is a schematic diagram illustrating a control unit 120 which 
interfaces with the continuous monitor modules 20, the cation conductivity 
monitors 32, the first and second valve systems 34, 38, and the ion 
chromatograph unit 42, as well as a power plant data center 121, to 
provide fully automatic water chemistry monitoring and calibration 
functions and to interface with overall plant operation. The control unit 
120 includes a microcomputer 122, a data bus 124, a serial multiplexer 
126, a plurality of continuous monitor module (CMM) interfaces 128, 
individually designated 128.sub.1, 128.sub.2, . . . 128.sub.n, 
corresponding to respective ones of the continuous monitor modules 20, a 
chomatograph interface 130, a valve system interface 132, a display 134, 
and a printer 136. The bus 124 receives control signals generated by the 
microcomputer 122 and supplies the control signals to the valve system 
interface 132, the CMM interfaces 128 via the serial multiplexer 126, and 
the chromatograph interface 130. Each CMM interface 128 may be, for 
example, Martek interface module, Model Mark XX, for receiving the 
temperature signals from temperature sensor 45 and the continuous monitor 
signals from continuous monitor unit 66, and providing actuator signals to 
shutoff valve 46 and the calibration unit 48. 
The control signals generated by the microcomputer 122 include calibration 
control signals, eluant supply control signals, sample volume control unit 
control signals for each of the chromatographs 86-88, chromatograph 
selector means control signals and first and second valve system control 
signals. These control signals are converted to corresponding actuator 
signals by the CMM interfaces 128, the chromatograph interface 130 and the 
valve system interface 132, each of which functions as a decoder/driver to 
generate the actuator signals necessary to operate the various valves and 
pumps at the appropriate voltages. The bus 124 also receives the 
chromatograph signals via th chromatograph interface 130 and the 
temperature signals and the continuous monitor signals generated by each 
continuous monitor module 20 via corresonding CMM interfaces 128 and the 
serial multiplexer 126 and supplies these signals to the microcomputer 
122. 
FIG. 5 is a block diagram of a standard valve arrangement employed in the 
sample volume control unit 98 to prepare a sample volume of an influent 
fluid sample stream for analysis. The sample volume control unit 98 
comprises a pump P for supplying the influent fluid sample stream at a 
predetermined volumetric rate in accordance with an activation signal ASP, 
and valves V1-V6 selectively operable in accordance with actuation signals 
AS1-AS6 to establish one of five flow paths FP1-FP5: the first flow path 
FP1 extends from the pump P through the injector loop 101 to valve V3; the 
second flow path FP2 extends from the pump P through the concentrator 
column 102 to a drain 22""; the third flow path FP3 extends from the 
eluant supply line 95 through the injection loop 101 to the separator 
column 104 (FIG. 3); the fourth flow path FP4 extends from the eluant 
supply line 95 through the concentrator column 102 to the separator column 
104; and the fifth flow path FP5 extends from the eluant supply line 95 to 
the separator column 104. The pump P provides the influent fluid samples 
stream at a known volumetric rate of flow and the pump 96 in the eluant 
supply system 89 provides the eluant at a known volumetric rate of flow so 
that control of the valves V1-V6 to establish flow paths FP-1-FP-5, and 
control of pump P and pump 96 as a function of time provides a specific 
volume of an influent fluid sample stream or an eluant. Actuation signals 
AS1-AS6 and ASP comprise sample volume control means actuator signals. 
Upon a determination that the calculated, required volume of the influent 
fluid sample to be prepared for analysis, the "sample volume", is the 
injection loop volume, the injection loop volume being defined as the 
combined volume of the first parallel fluid line 99 and the injection loop 
101, actuation signals AS1-AS6 are generated to establish flow path FP1. 
In particular, actuation signals AS1 and AS2 are generated to actuate 
valves V1 and V2 to provide the influent fluid sample stream to the 
injection loop 101, and actuation signal AS3 is generated to close valve 
V3. Then, actuation signal ASP is generated to operate pump P until the 
injection loop 101 and the first parallel fluid line 99 are filled with 
the influent fluid sample. Of course, the time necessary to fill the 
injection loop 101 and the first parallel fluid line 99 can be calculated 
from the known injection loop volume and the known volumetric flow rate 
provided by pump P. After the injection loop 101 and the first parallel 
fluid line 99 are filled with the influent fluid sample actuation signals 
AS1, AS4 and AS6 are generated to establish flow path FP3, and then 
actuation signal AS3 is generated to open valve V3 and pump 96 is actuated 
so that an eluant moves the sample volume of the influent fluid sample, 
which is equal to the injection loop volume, through the separator column 
104, the suppressor column 106, and the detector 108. 
Upon a determination that the sample volume is greater than the injection 
loop volume, but limited to a maximum load value, valves V1-V6 are 
operated to sequentially establish flow paths FP2 and FP4. First, 
actuation signal AS3 is generated to close valve and V3, Then, actuation 
signals AS1, AS2, and AS5 are generated to operate valves V1, V2, and V5 
to supply the influent fluid sample stream to the concentrator column 102 
and then to the drain 22"", thereby establishing flow path FP2. After flow 
path FP2 has been established, actuation signal ASP is generated to 
operate pump P for a time which provides the sample volume of the influent 
fluid sample stream. In this manner the sample volume of influent fluid 
sample stream is passed through the concentrator column 102 and the ions 
in the influent fluid sample stream are collected in a resin (not shown) 
in the concentrator column 102. When the ions from the predetermined 
volume of the influent fluid sample have been collected in the resin, 
actuator signals AS1, AS4 and AS5 are generated to actuate valves V1, V4 
and V5 to establish flow path FP4 and the pump 96 is actuated to supply an 
eluant through eluant supply line 95 at a predetermined volumetric rate. 
The eluant passes through the resin in the concentrator column 102 and 
carries the ions accumulated in the resin to the separator column 104, the 
suppressor column 106 and the detector 108. 
If it is desired to supply an eluant directly to the separator column 104, 
actuation signals AS4 and AS6 are generated to establish flow path FP5. 
Then, pump 96 is actuated to supply an eluant through supply line 95, 
supply line 138, and chromatograph fluid line 103 to the separator column 
104. 
FIG. 6 is a diagram of the conditioning unit 56 in the calibration unit 48 
shown in FIG. 2. The conditioning unit 56 may be an AQUAprep Chemical 
Injection System produced by Barnstead. The AQUAprep has been used to add 
chemicals to a fluid stream for purposes such as pH adjustment, 
chlorination, and dechlorination, the specific chemicals for these 
purposes being sulphuric acic (H.sub.2 SO.sub.4), sodium hypochlorite 
(NaOCl), and sodium bisulphite (NaHSO.sub.3), respectivley. The AQUAprep, 
however, has not been used to inject chemicals for the purpose of 
conditioning a fluid stream to calibrate chemical monitors. Further, the 
AQUAprep must be modified by substituting an appropriate mixed standard 
solution (described below) for the pH adjusting, chlorination, or 
dechlorination chemicals originally provided with the AQUAprep. In 
addition, the fluid flow of the AQUAprep has been modified to stabilize 
the chemical characteristics of the conditioned fluid sample. 
The operation of the conditioning unit 56 is as follows. The second portion 
of the influent fluid sample stream, the deionized second portion of the 
influent fluid sample stream, enters the calibration unit 56 at the input 
56a thereof and flows downward through an outer concentric tube 200 into a 
cartridge housing 202. It has been determined that modifying the AQUAprep, 
by adding a T-junction 203 and an external fluid line 204 to supply a 
portion of the influent fluid sample stream to the bottom of the cartridge 
housing 202, stabilizes the chemical characteristics of the conditioned 
fluid sample stream by causing all of the fluid in the cartridge housing 
202 to be exchanged. The influent fluid sample stream in the cartridge 
housing 202 enters a cartridge 206 via holes 207 therein, and surrounds 
and pressurizes a flexbile, two-ply plastic bag 208 containing a mixed 
standard solution 210. The flexibility of the plastic bag 208 assures that 
the pressure on the mixed standard solution 210 is exactly the same as the 
water pressure of the influent fluid sample stream outside of the bag 208. 
Further, there is no stress on the bag 208 because it simply defines a 
relaxed boundary between two liquids. The influent fluid sample stream 
then flows upward from the cartridge housing 202 through an inner 
concentric tube 212 to a fine adjustment valve 214, and then to a laminar 
flow element 216. The laminar flow element 216 creates a pressure 
differential by changing the turbulent flow of the influent fluid sample 
stream to laminar flow at the output of the laminar flow elment 216. This 
pressure differential causes the mixed standard solution 210 in the bag 
208 to be injected into the influent fluid sample stream at a mixing point 
218 through a flow restrictor 220 attached to the bag 208 and having a 
flow-restricting capilliary tube therein. Since the pressure differential 
is created by establishing a laminar flow of the influent fluid sample 
stream, and because the pressure in a fluid stream having laminar flow 
varies directly with flow rate, a change in the flow rate of the influent 
fluid sample stream produces a corresponding change in the injection rate 
of the mixed standard solution, and the dilution ratio of the mixed 
standard solution 210 in the influent fluid sample stream remains 
constant. Thus, the pressure of the influent fluid sample stream has no 
effect on the injection of the mixed standard solution; the injection rate 
is only affected by the pressure drop created by the laminar flow element 
216. The substitution of various flow restrictors 220 provides injection 
rates of approximately 0.5 ppm to approximately 160 ppm. In addition, the 
90.degree. turn at the mixing point 218 provides for mixing of the mixed 
standard solution in the influent fluid sample stream. 
The composition of the mixed standard solution 210 is dependent on the 
monitors which are being calibrated and the concentration of the chemicals 
in the mixed standard solution are varied in accordance with the injection 
rate to provide a conditioned influent fluid sample stream having chemical 
characteristics in the range of the chemical characteristics that the 
monitors are monitoring. In particular, by adding ammonium hydroxide 
(NH.sub.4 OH), sodium chloride (NaCl), and hydrazine (N.sub.2 H.sub.4), 
pH, specific conductivity, ammonia, cation conductivity, sodium, and 
hydrazine monitors can be calibrated. The concentration of ammonium 
hydroxide in the mixed standard solution is dictated by the range in which 
the pH monitor is to be calibrated. Most power plants operate with steam 
cycle water having a pH of approximately 9.5. Thus, the concentration of 
ammonium hydroxide in the mixed standard solution is adjusted in 
accordance with the injection rate and the flow rate of the influent fluid 
sample stream established by flowmeter 60 (FIG. 2) so that the conditioned 
influent fluid sample stream contains approximately 1.5 ppm of ammonium 
hydroxide to yield a pH of approximately 9.5. The ammonium hydroxide 
concentration is also directly related to the specific conductivity of the 
conditioned influent fluid sample stream--1.5 ppm of ammonium hydroxide 
yielding a specific conductivity of approximately 8 .mu.mhos. An ammonium 
monitor can be calibrated directly from the known concentration of ammonia 
(in ppm) in the conditioned influent fluid sample stream. The 
concentration of sodium chloride in the mixed standard solution is 
adjusted in accordance with the injection rate and flow rate so that the 
conditioned influent fluid sample stream has a concentration of 
approximately 33 ppb of sodium chloride. A concentration of 33 ppb of 
sodium chloride results in a chloride (Cl.sup.-) concentration of 20 ppb 
and a sodium (Na.sup.+) concentration of 13 ppb. The chloride 
concentration is related to cation conductivity and a sodium monitor can 
be calibrated a known concentration (in ppb) of sodium. If hydrazine is 
added to the mixed standard solution, the concentration of hydrazine in 
the mixed standard solution 210 should be selected to yield a 
concentration of approximately 50 ppb of hydrazine in the conditioned 
influent fluid sample stream. However, it may not be desirable to add 
hydrazine to the mixed standard solution 210 because it is a toxic 
chemical. Other species such as sulfate (SO.sub.4 --), in the form of 
sulfuric acid, copper (Cu), iron (Fe), and flouride (F.sup.-) in the form 
of soluable salts, and organic acids, for example, acetic acid and formic 
acid, may be included in the mixed standard solution in order to calibrate 
the ion chromatograph unit 42. 
It has been determined that high concentrations of ammonium hydroxide in 
the mixed standard solution cause the ammonium hydroxide to diffuse 
through the plastic bag 208, resulting in cracking of the cartridge 206. 
Thus, it is desirable to use a lower concentration of ammonium hydroxide 
in conjunction with a higher injection rate or to replace the bag 208 with 
a bag which is not permeable to higher concentrations of ammonium 
hydroxide. 
The operation of the continuous on-line water chemistry monitor system of 
the present invention will be described with reference to the flowcharts 
in FIGS. 7-16. 
FIGS. 7A and 7B are flowcharts showing the overall operation of the system 
of the present invention. 
Step 900: Initialization and start-up of the system, including selecting 
analyses to be performed in the initial run, as shown in detail in FIG. 8. 
Step 902: Determination of the sampling sequence for the first and second 
valve systems 34, 38, i.e., the order in which the first and second valve 
systems 34, 38 supply the third and fourth influent fluid sample streams 
to the ion chromatograph unit 42, as shown in detail in FIG. 9. 
Step 904: Determine if a predetermined calibration interval has elapsed. If 
the calibration interval has elapsed, calibration is to be performed and 
processing proceeds to step 915. If calibration is not to be performed, 
processing proceeds to step 906. 
Step 906: Operation of the ion chromatograph unit 42 to perform anion 
chromatography, organic acid chromatography, and cation chromotography, as 
shown in detail in FIGS. 10-12. 
Step 908: Calculation of a strong acid temperature compensated cation 
conductivity based on the monitored temperature of the influent fluid 
sample stream analyzed by the ion chromatograph unit, predetermined 
conductivity equations, and the ions detected by anion chromatography and 
cation chromatography. 
Step 910: Determine if organic acid chromatography was performed. 
Step 912: If organic acid chromatography was performed, calculate cation 
conductivity including organic acids at the monitored temperature, as 
shown in detail in FIG. 14. 
Step 914: Determine if the calculated cation conductivity including organic 
acids is approximately equal to the monitored conductivity. If these two 
values do not correspond within experimental error, processing proceeds to 
step 905 for calibration. If these values do not correspond, processing 
proceeds to step 915; if these values do correspond, processing proceeds 
to step 916. 
Step 915: If it is determined, in step 904, that calibration is to be 
performed, calibration and malfunction diagnoses are performed, as shown 
in detail in FIG. 16. 
Step 916: Determine if organic acid chromatography is required in the 
subsequent run by comparing the strong acid temperature compensated cation 
conductivity with the monitored cation conductivity. If these valves are 
not approximately equal, it is determined that organic acid chromatography 
is to be performed on the next third influent fluid sample stream to be 
supplied to the ion chromatograph unit 42. 
Step 918: If organic acid chromatography is determined to be required in 
the next run, a flag is set for organic acid chromatography. 
Step 920: A cation conductivity for 25.degree. C. is calculated, and the 
calculated conductivity at 25.degree. C. and the results of all other 
analyses are displayed. Processing then returns to step 902. 
FIGS. 8-16 are flowcharts detailing the operations shown in the flow chart 
of FIG. 7. In particular, FIG. 8 is a flow chart illustrating the 
initialization and start-up procedure. 
Step 1000: Enter date and time. 
Step 1002: Enter high and low cation conductivity alarm values. 
Step 1004: Enter maximum dormant period, i.e., the maximum time between ion 
chromatographic analysis of the influent fluid sample stream supplied by a 
particular one of the fluid lines 10. The maximum dormant period may be 
set at, for example, one day (24 hours). 
Although the maximum period between the ion chromatograph analyses of a 
particular sample may be as long as 24 hours, the continuous monitors 
68-73 in each continuous monitor module 20, as well as the cation 
conductivity monitors 32, provide continuous on-line monitoring of each 
influent fluid sample stream. Further, it is unlikely that the maximum 
dormant period will elapse between chromatographic analyses of a 
particular influent fluid sample stream since the time necessary for each 
run of the ion chromatograph unit 42 is approximately one half hour. 
Step 1006: Designate sample pointers with corresponding fluid lines 
10.sub.1, 10.sub.2, . . . 10n. 
Step 1008: Set sample pointer to 1. 
Step 1010: Enter slope and intercept values from a known equation 
describing the relationship between the cation conductivity and the 
concentration of anions and organic acids in a fluid sample. This equation 
is used to determine the volume of a fluid sample necessary to provide the 
quantity of anions or organic acids which are necessary for accurate 
chromatographic analysis, i.e., the "sample volume" for the anion 
chromatograph 86. 
Step 1012: Enter maximum volume for loading the anion chromatograph 
concentrator column 102. Enter the injection loop volume for the anion 
chromatograph 86. 
Step 1014: Enter slope and intercept values for a known equation describing 
the relationship of the specific conductivity and the concentration of 
cations in a fluid sample. This equation is used to determine the volume 
of a fluid sample necessary to provide the quantity of cations necessary 
for accurate cation chromatography, i.e., the "sample volume" for the 
cation chromatograph. 
Step 1016: Enter maximum volume for loading cation chromatography 
concentrator column. Enter the injection loop volume for the cation 
chromatograph 88. 
Step 1018: Determine if the maximum loading volumes and injection loop 
volumes for all chromatographs 86-88 are within acceptable limits when 
compared to default values. 
Step 1020: List default values on display 95 or printer 96, shown in FIG. 
4, if the loading parameters are not within the acceptable limits when 
compared with default values and return to step 1010. 
Step 1022: Set calibration interval for continuous monitor modules 20 and 
for the ion chromatograph unit 42. 
Step 1023: Set flag and select eluant for organic acid analysis in initial 
run, and proceed to flow D (FIG. 9). 
FIG. 9 is a flowchart describing the determination of the sequence in which 
the influent fluid sample streams, supplied by each of the fluid lines 10, 
are provided to the ion chromatograph unit 42. 
Step 1024: Increase sample pointer by 1. 
Step 1026: Determine if sample pointer value is greater than the number n 
of fluid lines 10. 
Step 1028: Set pointer to 1 if the pointer value is greater than the number 
n of fluid lines 10. From this point processing is performed for the 
influent fluid sample stream supplied by the fluid line 10 corresponding 
to the sample pointer value. 
Step 1030: Determine if the monitored cation conductivity is above the high 
alarm value set in step 1002. If the monitored cation conductivity value 
is above the high alarm value processing proceeds to flow E (FIG. 10). 
Step 1032: Determine if the monitored cation conductivity is above the low 
alarm value. If the cation conductivity is above the low alarm value, 
processing proceeds to flow E. If the cation conductivity is not above the 
low alarm value, it is determined that the influent fluid sample stream 
does not contain a high enough concentration of ions to justify performing 
chromatographic analysis. 
Step 1034: Determine if the influent fluid sample stream associated with 
the selected fluid line 10 has been analyzed within the maximum dormant 
period set in step 1004. If the fluid sample has not been analyzed within 
the maximum dormant period, processing proceeds to flow E. If the fluid 
sample has been analyzed within the maximum dormant period, processing 
returns to step 1024. 
The flow charts of FIGS. 10-12 provide an illustration of the control of 
the operation of the ion chromatograph unit 42. 
Step 1036: Determine if the calibration interval has elapsed. If the 
interval has elapsed, processing proceeds to flow K, shown in FIG. 16, for 
calibration. 
Step 1037: Instruct first and second valve system subroutines to provide 
the altered third and fourth fluid sample streams corresponding to the 
influent fluid sample stream supplied by the fluid line 10 corresponding 
to the sample pointer to the ion chromatograph unit 42. The first and 
second valve system subroutines can be generated by one of ordinary skill 
in the art in accordance with the disclosure in U.S. Pat. No. 4,414,858, 
previously incorporated by reference. 
Step 1038: Calculate an anion chromatograph sample volume with 
predetermined equations, particularly by multiplying the monitored cation 
conductivity with the slope entered in step 1010 and then adding the 
intercept value entered in step 1010. 
Step 1040: Determine if the calculated sample volume is greater than the 
maximum load volume for the anion chromatograph concentrator column 
entered in step 1012. If the calculated sample volume is greater than the 
maximum load volume, processing proceeds to step 1042; otherwise, 
processing proceeds to step 1044. 
Step 1042: Set anion chromatograph sample volume to the maximum load volume 
if the calculated sample volume is greater than the maximum load volume, 
then proceed to step 1050. 
Step 1044: Determine if the calculated sample volume is less than or equal 
to the injection loop volume set in step 1012. If the calculated sample 
volume is greater than the injection loop volume, processing proceeds to 
step 1050. If the calculated sample volume is less than or equal to the 
injection loop volume, processing proceeds to step 1046. 
Step 1046: Instruct a valve control subroutine for the anion chromatograph 
86 sample volume control unit 98 to use the injection loop 101 (FP-1) 
instead of the concentrator column 102 (FP-2), if the calculated sample 
volume is less than or equal to injection loop volume. The valve control 
subroutine can easily be developed by one of ordinary skill in the art in 
accordance with the description of the operation of the sample volume 
control unit 98 previously provided. 
Step 1048: Set sample volume to the loop volume. 
Step 1050: Inform concentration calculation subroutines of the sample 
volume, i.e., the calculated sample volume if it is greater than the 
injection loop volume and less than the maximum load volume, the maximum 
load volume set in step 1042 if the calculated sample volume is greater 
than the maximum load volume, or the loop volume set in step 1048 if the 
calculated sample volume is less than or equal to the injection loop 
volume. The concentration calculation subroutines can be developed by one 
of ordinary skill in the art based on the operation of standard 
chromatographs. After the anion chromatograph sample volume is determined, 
processing proceeds to flow F (FIG. 11). 
Step 1052: Calculate cation chromatograph sample volume with predetermined 
equations, particularly by multiplying the monitored specific conductivity 
with the slope entered in step 1014 and then adding the intercept value 
entered in step 1014. 
Step 1054: Determine if the calculated cation chromatograph sample volume 
is greater than the maximum load volume set in step 1016. If the 
calculated sample volume is grater than the maximum load volume, 
processing proceeds to step 1056; otherwise, processing proceeds to step 
1058. 
Step 1056: Set cation chromatograph sample volume to maximum load volume if 
the calculated sample volume is greater than the maximum load volume. 
Step 1058: Determine if the calculated sample volume is less than or equal 
to the injection loop volume set in step 1016. 
Step 1060: Instruct cation chromatograph sample volume control unit (not 
shown) valve control subroutine to use an injection loop (FP-1) instead of 
a concentrator column (FP-2), if the calculated sample volume is less than 
or equal to the injection loop volume. 
Step 1062: Set sample volume to the injection loop volume. 
Step 1064: Inform concentration calculation subroutine of the sample 
volume. After the cation chromatograph sample volume is determined, 
processing proceeds to flow G (FIG. 12). 
Step 1065: Set the organic acid chromatograph sample volume to the anion 
chromatograph sample volume and instruct valve control and concentration 
calculation subroutines accordingly. 
Step 1066: Determine if the flag is set for an organic acid analysis. For 
the initial run, the flag is set in step 1023, and for subsequent runs the 
flag for organic acid analysis is set in the processing of flow J (FIG. 
15). If the organic acid analysis flag is not set, processing proceeds to 
step 1076. 
Step 1068: Determine if the time for the separation of flouride (F.sup.-) 
and formate (an anion often found in power plant steam cycle water) which 
occurs in the organic acid chromatograph separator column (not shown), is 
greater than one minute during the previous run of the organic acid 
chromatograph 87 in order to select the appropriate eluant. In the initial 
run the eluant is selected in step 1023. The separation time is determined 
by the order of the peaks for flouride and formate in the analysis of the 
previous run, and one of ordinary skill in the art would be able to 
instruct the control system to determine the order of the peaks 
automatically. 
Step 1070: If the separation time during the previous run was greater than 
one minute, a valve control subroutine for the eluant supply system 89 is 
instructed to supply a pH 4 eluant. One of ordinary skill in the art would 
be able to develop a valve control subroutine for actuating the eluant 
selector valve 94 to select a pH 3 or pH 4 eluant. 
Step 1072: If the separation time during the previous run was one minute or 
less, the valve control subroutine for the eluant supply system 89 is 
instructed to supply a pH 3 eluant. 
Step 1074: Initiate organic acid chromatography. 
Step 1076: Initiate anion chromatography. 
Step 1078: Initiate cation chromatography and then proceed to flow H (FIG. 
13). 
The flow chart of FIG. 13 relates to the calculation of a strong acid 
temperature compensated cation conductivity using predetermined 
conductivity equations. 
Step 1080: Obtain the monitored temperature of the fluid sample undergoing 
chromatographic analaysis from the corresponding continuous monitor module 
20. 
Step 1082: Calculate the dissociation constant for water (Kw) using the 
monitored temperature obtained in step 1080 and a value obtained from a 
computer resident look-up table based on data presented in a table of 
Ionization Constants for water (Kw) presented in the Handbook of Chemistry 
and Physics, 56th Ed., (CRC Press, Cleveland 1975), page D-152. Calculate 
the equilibrium, or inonization constants for all weak acids which can be 
determined by ion exclusion chromatography using the monitored temperature 
and values obtained from a computer resident look-up table based on data 
presented in a table of Ionization Constants of Acids in Water at Various 
Temperatures presented in the Handbook of Chemistry and Physics at page 
D-152. 
Step 1084: Calculate H.sup.+ and OH.sup.- concentrations using the 
dissociation constant Kw and strong acid anion concentrations determined 
by ion chromatography by solving the following equations (1) -(5) 
simultaneously: 
##EQU1## 
wherein Kw= is the equlibrum contant for water at the monitored 
termperature; 
K.sub.A.sub.i is the equilibrium constant for the with weak acid, HA.sub.i, 
which has been determined by organic acid chromatography; 
[H.sup.+ ] is the concentration of the hydrogen ion; 
[A.sub.i .sup.- ] is the concentration of the conjugate base of the ith 
acid, HA; 
[HA.sub.i ] is the concentration of the ith acid, HA.sub.i ; and 
[OH.sup.- ] is the concentration of the hydroxide ion. 
##EQU2## 
wherein n is the number of weak acids determined by organic acid 
chromatograph; and 
m is the number of strong acid anion concentrations determined by ion 
chromatography. 
Mass Balance Equations 
EQU F.sub.i =[HA.sub.i ]+[A.sub.i .sup.- ] (4) 
EQU F.sub.j =[B.sub.j .sup.- ]. (5) 
Step 1086: Calculate the equivalent conductance for each ion which can be 
detected by ion chromatography using the monitored temperature obtained in 
step 1080 and values obtained from a computer resident look-up table based 
on the data presented in a table of the Equivalent Conductance Separate 
Ions presented in the Handbook of Chemistry and Physics at page D-153. 
Step 1088: Calculate the strong acid contribution to the monitored cation 
conductivity using strong acid anion concentrations, [H.sup.+ ], [OH.sup.- 
], and the temperature corrected equivalent conductances, and calculate a 
strong acid temperature compensated cation conductivity using the 
temperature corrected equivalent conductances and equation (6) below. 
##EQU3## 
wherein cc is the cation conductivity; 
.sub.H + is the equivalent conductance of the hydrogen ion; 
.sub.OH - is the equivalent conductance of the hydroxide ion; 
.sub.i is the equivalent conductance of the conjugate base of the ith 
weak acid; and 
.sub.j is the equivalent conductance of the jth strong anion. 
Since the concentrations of the weak acids determined by organic acid 
chromatograph are represented by [A.sub.i .sup.- ] and [HA.sub.i ], only 
equations (1), (3) and (5) must be solved to calculate the strong acid 
anion concentrations for the strong acids determined by anion 
chromatography. Thus, to determine the strong acid anion concentrations, 
[A.sub.i .sup.- ]=0 for all i. 
To obtain the cation conductivity which includes both weak acid and strong 
acid anion concentrations, equations. (1)-(6) are solved simultaneously 
for cc. 
Step 1090: Determine if organic acid analysis was performed during the run. 
If organic acid analysis was performed processing proceeds to flow G, and 
if organic acid analysis was not performed, processing proceeds to flow I 
(FIG. 14). 
The flowchart of FIG. 14 relates to the calculation of a cation 
conductivity, including the organic acid concentrations determined by 
organic acid chromatography, at the monitored temperature. 
Step 1092: Obtain concentrations of all of the ionic species, including 
organic acids, determined by ion chromatography by solving equations 
(1)-(5) including all Fi values obtained by organic acid chromatography. 
Step 1094: Calculate cation conductivity at monitored temperature using 
concentrations of ionic species, including organic acids, obtained in step 
1092. 
Step 1096: Determine if the calculated cation conductivity at the monitored 
temperature, including organic acids, is approximately equal to the 
monitored cation conductivity, within the range of experimental error. If 
the calculated cation conductivity at the monitored temperature is not 
approximately equal to the monitored conductivity, processing proceeds to 
flow K (FIG. 16) for calibration. If the calculated cation conductivity at 
the monitored temperature is approximately equal to the monitored cation 
conductivity, processing proceeds to flow J (FIG. 15). 
Step 1098: Determine if strong acid temperature compensated cation 
conductivity is approximately equal to the monitored cation conductivity. 
If these two values are not approximately equal, it is determined that 
organic acid analysis is required in the next, or subsequent, run and 
processing proceeds to step 1100; otherwise, processing proceeds to step 
1102. 
Step 1100: Set flag for organic acid analysis in subsequent run. 
Step 1102: The measured composition of the sample fluid is used to 
calculate the cation conductivity at 25.degree. C. This prediction is 
based on known parameters referenced in step 1082. 
Step 1104: Display and record temperature corrected cation conductivity. 
Step 1106: Display and record all other analytical results and proceed to 
flow D (FIG. 9) to perform subsequent run. 
Flow K, shown in FIG. 16, relates to calibration and malfunction diagnosis. 
Step 1108: If the calculated cation conductivity is not determined to be 
approximately equal to the detected conductivity at step 1096, the 
calibration subroutine is instructed to calibrate the continuous on-line 
monitors 68-73 in the continuous monitor module 20 corresponding to the 
influent fluid sample stream being analyzed during the run and the ion 
chromatograph unit 42. The corresponding calibration unit 48 is operated 
by a valve control subroutine which can be developed by one skilled in the 
art in accordance with the above description of the operation of the 
calibration unit 48. 
Step 1110: Determine if the monitored chemical characteristics during 
calibration are within expected values, i.e., are the monitored chemical 
characteristics in the range of the predetermined chemical characteristics 
of the conditioned influent fluid sample stream. 
Step 1112: If it is determined, at step 1110, that the chemical 
characteristic monitored by a particular instrument is not within the 
range of expected values during calibration, the operator is alerted of 
the malfunction of the particular instrument. The processing then proceeds 
to flow J (FIG. 15). 
Step 1114: If the responses during calibration are all within the expected 
values, the cation conductivity is recalculated using the new calibration 
factors. 
Step 1116: Determine if the monitored and calculated cation conductivities 
are approximately equal. If the conductivities are approximately equal, 
processing proceeds to flow J. 
Step 1118: If the measured and calculated cation conductivities do not 
match, the operator is alerted of the presence of an unmeasured anion and 
processing continues to flow J. 
It will be apparent to one skilled in the art, from the detailed 
specification, that the number of fluid lines 10 and thus the number of 
continuous monitor modules 20 is not limited; the steam cycle water from 
only one point in a power plant steam cycle or the steam cycle water from 
n points in a power plant steam cycle may be monitored by using 1 to n 
fluid lines 10 and continuous monitor modules 20. Additionally, each 
continuous monitor module 20 may serve to analyze influent fluid sample 
streams derived from one or more points in the power plant steam cycle by 
one or more fluid lines 10. Further, although it may be advantageous to 
employ plural cation conductivity monitors 32 for receiving a portion of 
each influent fluid sample stream and monitoring the cation conductivity 
thereof, a single cation conductivity monitor 32 could be shared by a 
plurality of continuous monitor modules 20 since altered third fluid 
sample streams having cations, including ammonia, removed therefore, are 
only required when the corresponding fluid sample stream is being supplied 
to the ion chromatograph unit 42. The use of a single ion chromatograph 
unit 42 likewise is not limiting in that the system could be expanded to 
operate with more than one ion chromatograph unit 42 -- groups of influent 
fluid sample streams could be supplied to each of several ion 
chromatograph units, or an ion chromatograph unit could be provided for 
each influent fluid sample stream. 
The many features and advantages of the automatic continuous on-line 
monitoring system of the present invention will be apparent to those 
skilled in the art from the detailed specification. Further, since 
numerous modifications and changes will readily occur to those skilled in 
the art, the claims are intended to cover all suitable modifications and 
equivalents falling within the true spirit and scope of the invention.