Patent Description:
Generally, a Sample Handling System (SHS) is deployed in an industry for analyzing, and processing/conditioning samples like gas mixture, fluid to improve efficiency of a process at an initial stage. Mostly, the SHS are used for filtrations, isolation and pressure/temperature/flow control at gas analyzer systems especially in industrial gas treatment, semiconductor, furnace gas and heat treatment.

When considering the SHS for gas analysis, a collection of the gas mixture comprising a flue gas from a pipeline has to undergo a purification process before delivering the gas mixture to a gas analyzer. The purification process generally takes place in the SHS. While, there are different designs of the SHS, the function of the SHS remains the same, which is to condition/purify the gas mixture to remove dust, moisture and corrosive substances from the gas mixture.

In the conditioning/purifying process of the gas mixture (gas samples), there are certain parameters that influence a performance of the SHS. In that, moisture content in the gas mixture is a crucial parameter that influences the performance of the gas analyzer in the SHS. In general, several types of equipment such as a gas cooler, a coalescence filter of thermoelectric condenser are being used conventionally to remove the moisture content from the gas mixture. However, it is not assured that a maximum volume of the moisture content is removed completely before sending to the gas analyzer. In order to address this issue, a hardware based moisture sensors are implemented in the SHS to monitor and estimate the moisture content of the gas mixture. The implementation of the hardware based moisture sensors increase cost of the SHS. Further, the implementation of the hardware based moisture sensors may require an undesirable change in a design of a conventional SHS. <CIT> describes estimating a moisture content in a Sample Handling System, but not on a comparison of a calculated versus an actual surface area of the gas cooler.

Therefore, in light of the foregoing discussions, there is a need for a system and method for estimating the moisture content in the gas mixture without any additional cost.

It is an object of the present disclosure to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages in the prior art and solve at least the above-mentioned problem.

In view of the foregoing, the invention provides a system for estimating a moisture content of a gas mixture in a Sample Handling System and a method for estimating moisture content of a gas mixture in a Sample Handling System.

According to the invention, a system for estimating moisture content of a gas mixture in the Sample Handling System, SHS, provided, comprising a data pre-processing module and a moisture content estimation module. The data pre-processing module is configured to receive data comprising measurements of the SHS related to the gas mixture, a gas cooler and a coolant; and a plurality of parameters related to the gas mixture. The data pre-processing module is configured to analyze the received data to remove one or more anomalies in the data. The moisture content estimation module is configured to determine thermodynamic properties, heat transfer coefficient (U) and mass transfer coefficient (K) of the gas mixture based on the analyzed data. The moisture content estimation module is configured to calculate a surface area (A) of the gas cooler based on the analyzed data and the determined thermodynamic properties, heat transfer coefficient (U) and mass transfer coefficient (K) of the gas mixture. The moisture content estimation module is configured to estimate the moisture content of the gas mixture based on comparison of the calculated surface area (A) of the gas cooler with an actual surface area (CA) of the gas cooler.

According to an embodiment, the moisture content estimation module is configured to calculate the surface area of the gas cooler by determining initial temperatures (initial temperature profiles) of the gas mixture at the gas cooler of the SHS using computational fluid dynamics finite volume/finite element simulations. The flow of the gas mixture at an inlet of the gas cooler is predefined.

According to an embodiment, the moisture content estimation module is configured to estimate the moisture content of the gas mixture based on comparison of the calculated surface area of the gas cooler with the actual surface area of the gas cooler by determining that the calculated surface area (A) of the gas cooler matches with an actual surface area (CA) of the gas cooler. In response to the determination, the moisture content estimation module is configured to provide: an estimated flow of the gas mixture at the inlet of the gas cooler and condensate, an estimated temperature of the coolant at the outlet of the coolant and the moisture content of the gas mixture at the inlet and an outlet of gas cooler.

According to another embodiment, the moisture content estimation module is configured to iteratively perform the estimation of the thermodynamic properties, heat transfer coefficient (U) and mass transfer coefficient (K) of the gas mixture using the analyzed data with a modified value for the flow of the gas mixture at the inlet of the gas cooler, in response to the determination that the calculated surface area (A) of the gas cooler not matches with the actual surface area (CA) of the gas cooler.

According to an embodiment, the data-preprocessing module is further configured to analyze the data to remove one or more anomalies in the measurements of the SHS by assigning missing values of the measurements (M1-M6, S1) of the SHS, removing noise and outliers in the data using techniques for imputation, and filtering techniques.

According to an embodiment, the measurements of the SHS related to the gas mixture, the gas cooler and the coolant includes real time data from the gas cooler and the coolant of the SHS. The real time data includes pressure, temperature and flow of the gas mixture, the gas cooler and the coolant. The real time data from the gas cooler and the coolant of the SHS includes the temperatures and the flows at the inlet and the outlet of the gas cooler and at an inlet of the coolant.

According to an embodiment, the plurality of parameters related to the gas mixture comprises parameters for determining the thermodynamic properties of the gas mixture. The thermodynamic properties of the gas mixture includes specific heat, heat of condensation, saturated vapor pressure and dynamic viscosity.

According to an embodiment, the plurality of parameters related to the gas mixture comprises a plurality of curves. The plurality of curves comprises Chilton curves. The Chilton curves provide Chilton factor based on Reynolds number of flow and the Chilton factor is utilized for determining the heat transfer coefficient (U) and mass transfer coefficient (K).

According to the invention, a method for estimating the moisture content in the gas mixture in the Sample Handling System, SHS, is provided. The method comprising the steps of: receiving data comprising measurements of the SHS related to the gas mixture, a gas cooler and a coolant; and a plurality of parameters related to the gas mixture; analyzing the received data to remove one or more anomalies from the data; determining thermodynamic properties, heat transfer coefficient (U) and mass transfer coefficient (K) of the gas mixture based on the analyzed data; calculating a surface area of the gas cooler based on the analyzed data and the determined thermodynamic properties, heat transfer coefficient (U) and mass transfer coefficient (K) of the gas mixture; and estimating the moisture content of the gas mixture based on comparison of the calculated surface area of the gas cooler with an actual surface area of the gas cooler.

The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments and detailed in the following description. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein.

As mentioned above, there is a need for a system and a method for estimating moisture content in a gas mixture comprising a flue gas and water vapor by making use of measurements of SHS without any additional cost. The embodiments herein achieve this by providing a system and a method for estimating the moisture content in the gas mixture comprising the flue gas (exhaust gas or stack gas) and water vapor.

<FIG> illustrates a schematic of a conventional/ existing Sample Handling System (SHS) <NUM>. The conventional SHS <NUM> includes a plurality of components to purify a gas mixture comprising a flue gas and water vapor before the gas mixture is analyzed at a gas analyzer. The SHS <NUM> may be implemented in power plants, refineries, petrochemical and chemical plants, among others. The Sample Handling Systems, SHS, are used for isolation, filtration, and pressure/temperature/flow control of analyzer systems especially implemented in industrial gas treatment, furnace gas and heat treatment, semiconductor fabrication, power generation, air dryer and pharmaceutical applications. While, there may be different types and designs of commercially available SHS, the function of all types of SHS remains the same, which is to condition the gas mixture to remove dust, moisture and corrosive substances from the gas mixture. The gas mixture is obtained from a flue gas stack <NUM> and is passed through a pipe or a flue to exit into an atmosphere. While the gas mixture passes through the pipe/pipeline, the gas mixture is conditioned in the SHS <NUM> using a number of components of the SHS <NUM> to remove the moisture from the gas mixture. The term "conditioned" herein may correspond to exposing the gas mixture to a certain temperature to heat it and cool it using a coolant.

The flue gas comprised in the gas mixture refers to the gas being released into the atmosphere via the flue, which is the pipe or a channel for conveying exhaust gases from industrial plants. A composition of the flue gas depends on material that is burned. However, the composition of the flue gas usually comprises of nitrogen derived from the combustion of air, carbon dioxide, water vapor as well as oxygen. The composition of the flue gas further comprises a small percentage of a number of pollutants, such as particulate matter, carbon monoxide, nitrogen oxides, and sulfur oxides. The different measurements are obtained at various gas-mixture processing stages of the SHS <NUM> and the various gas mixture processing stages of the SHS <NUM> are described below.

The SHS <NUM> includes the flue gas stack <NUM> from where the gas mixture comprising the flue gas and the water vapor is fed into the SHS <NUM>. The SHS <NUM> further includes a sample probe <NUM> and a heat tracer line <NUM>. The sample probe <NUM> and the heat tracer line <NUM> comprising a ring heater and a ceramic filter as integral parts. The SHS <NUM> further includes a gas cooler <NUM>, a sample pump <NUM> and a gas analyzer <NUM>. Upon being analyzed, the gas mixture provides various gases <NUM> as an output that are present in the composition of the flue gas as described earlier.

The gas mixture is taken into the SHS <NUM> via the sample probe <NUM>. The gas mixture is filtered to remove dust/colloidal particles using a ceramic filter and is heated by the ring heater of the sample probe <NUM> and the heat tracer line <NUM>. Temperature of the ring heater is maintained at a value "M1" and temperature of the heat tracer line <NUM> is maintained at a value "M2". By maintaining the temperatures of the ring heater at M1 and the heat tracer line <NUM> at M2, the gas mixture that passes from the sample probe <NUM> to the gas cooler <NUM> is heated. The heating is performed to maintain a desired temperature of the gas mixture until the gas mixture reaches the gas cooler <NUM>. This is required to avoid condensation of the moisture in the pipeline which otherwise creates several operational problems.

The coolant being introduced into the gas cooler through an inlet of the coolant (shown in <FIG>), which is different from an inlet of the gas cooler (shown in <FIG>) through which the heated gas mixture enters the gas cooler <NUM>. The gas cooler <NUM> and its various inlets and outlets are described in-detail in reference with <FIG>. Once the heated gas mixture reaches the gas cooler <NUM>, the coolant that has entered the gas cooler <NUM> removes the heat from the gas mixture. This removal of heat from the gas mixture is resulted in condensation of the moisture and that is removed as condensate <NUM>. The dry gas mixture is then pumped via the sample pump <NUM> to the gas analyzer <NUM> for analyzing the various gases.

The various gases are the gases being released into the atmosphere as an output <NUM> and are composed of gases such as nitrogen (N<NUM>), carbon dioxide (CO<NUM>), oxygen (O<NUM>). It also includes water vapor as well as small percentage of pollutants, carbon monoxide (CO), nitrogen oxides (NO, NO<NUM>, etc.,) , sulfur oxides (SO, SO<NUM> etc.,) and so on.

The SHS <NUM> is configured to perform measurements (M1-M6 , S1) related to the gas mixture, the gas cooler and the coolant at various inlets, outlets and bodies of the various gas mixture processing stages of the SHS <NUM> and generate data corresponding to the measurements. For example, temperature and pressure are measured at an inlet and an outlet of the gas cooler <NUM>. Temperature within the gas cooler <NUM> and pump discharge pressure is measured. This measured data is a real time data. The measurements of the SHS related to pressure, temperature and flow of the gas mixture, the gas cooler and the coolant includes the real time data obtained from the plurality of measurements. The real time data includes the ring heater temperature M1, the heat tracer line temperature M2, a pressure M3 at the inlet of the gas cooler <NUM>, a temperature M4 at the gas cooler <NUM>, a pressure M5 at the outlet of the gas cooler <NUM>, the pump discharge pressure M6 and a flow measurement S1, among other measurements.

Some or all of these real time data can be used for estimation of the moisture content in the gas mixture. The estimation of the moisture content in the gas mixture is performed using one or more modules where the real time data and other data can be pre-processed and the moisture content in the gas mixture is estimated. The estimation of the moisture content in the gas mixture and the modules used for the estimation are described in the <FIG>.

<FIG> illustrates a system <NUM> for estimating moisture content of a gas mixture in a Sample Handling System (SHS), according to a first aspect of an embodiment herein. The SHS may be the exemplary SHS <NUM> described in reference to <FIG>. The system <NUM> includes a data pre-processing module <NUM> and a moisture content estimation module <NUM>. The data pre-processing module <NUM> and the moisture content estimation module <NUM> may be modules independent from the SHS <NUM>. The system <NUM> further includes the various gas mixture conditioning stages of the SHS <NUM>. The various conditioning stages of the SHS includes a flue gas stack <NUM>, a sample probe <NUM>, a gas cooler <NUM>, a sample pump <NUM> and a gas analyzer <NUM>. The various gases <NUM> are being released into the atmosphere as described earlier. The flue gas stack <NUM>, a sample probe <NUM>, a gas cooler <NUM>, a sample pump <NUM> and a gas analyzer <NUM> may be same as the sample probe <NUM>, the gas cooler <NUM>, the sample pump <NUM> and the gas analyzer <NUM> as described in reference with <FIG> and are not repeated for the sake of brevity. Although not shown, one could infer that the system <NUM> comprises a ring heater and a ceramic filter within the sample probe <NUM> as integral parts of the sample probe <NUM> and a heat tracer line similar to the heat tracer line <NUM>.

Alternatively, the data pre-processing module <NUM> and the moisture content estimation module <NUM> may be discrete and separate modules placed remotely from each other. The data pre-processing module <NUM> and the moisture content estimation module <NUM> may include one or more processors, a memory and communication interfaces to communicate data between the data pre-processing module <NUM> and the moisture content estimation module <NUM>. For example, the data pre-processing module <NUM> is configured to provide the analyzed data for the estimation of the moisture content of the gas mixture to the moisture content estimation module <NUM> via one or more of the communication interfaces.

Examples of communication interfaces may include one or more inter or intra system buses such as USB and SPI, among others. Such communication interfaces may be implemented when the data pre-processing module <NUM> and the moisture content estimation module <NUM> are within a single device. Examples of communication interfaces may also include, wireless communication network and wired communication networks. Such communication interfaces may be implemented when the data pre-processing module <NUM> and the moisture content estimation module <NUM> are remotely placed from one another. Since, the data pre-processing module <NUM> and the moisture content estimation module <NUM> are independent and not a part of the SHS <NUM>, this provides a solution for estimating moisture content without additional hardware components being added to the SHS <NUM> that could increase the cost of the SHS <NUM>.

According to the embodiment, the data pre-processing module <NUM> is configured to receive data <NUM>. The data <NUM> includes measurements (M1-M6, S1) of the SHS <NUM> related to the gas mixture, the gas cooler and the coolant, and a plurality of parameters related to the gas mixture comprising the flue gas and water vapor. The measurements (M1-M6, S1) of the SHS includes real time data from the gas cooler (<NUM>, <NUM>) and the coolant. The real time data from the gas cooler <NUM> and the coolant includes temperatures and flows of a gas cooler <NUM> and a coolant. The temperatures and the flows of the gas cooler <NUM> and the coolant includes the temperature of the gas cooler <NUM> at an inlet (shown in <FIG>) and an outlet (shown in <FIG>), the flow of the gas cooler <NUM> at the outlet, the temperature at an inlet (shown in <FIG>) of the coolant and the flow of the coolant at the inlet (shown in <FIG>).

The plurality of parameters related to the gas mixture comprises parameters for determining thermodynamic properties of the gas mixture. The thermodynamic properties of the gas mixture includes parameters, which include coefficients that are used in a set of equations (described in <FIG>) to estimate thermodynamic properties of the compositions of the flue gas in the gas mixture. For example, the coefficients includes but is not limited to heat transfer coefficient (H), a mass transfer coefficient (M) and so on. The thermodynamic properties of the gas mixture includes, but are not limited to, specific heat, heat of condensation, saturated vapor pressure and dynamic viscosity.

The real time data further includes a pressure (M3) at the inlet of the gas cooler <NUM>, pressure (M5) at the outlet of the gas cooler <NUM> and a pump discharge pressure (M6). The plurality of curves includes Chilton curves (not shown). The Chilton curves provide Chilton factor based on Reynolds number of flow (Re).

The data pre-processing module <NUM> is configured to analyze the received data to remove one or more anomalies from the data <NUM>. The data <NUM> is analyzed for any missing values measurements (M1-M6, S1) of the SHS <NUM>, noise and outliers in the data <NUM>. The data-preprocessing module <NUM> is further configured to assign the missing values in the measurements (M1-M6, S1) of the SHS <NUM> using known techniques for imputation, and remove the noise and outlier in the data <NUM> using known filtering techniques based on the type of application. For example, upon receiving the data <NUM>, the data is analyzed for any missing values in the measurements (M1-M6, S1) of the SHS <NUM> and then those missing values may be imputed. A technique herein may be defined as a set of algorithms or instructions that define the manner in which a particular task needs to be performed. For example, the technique for imputation may correspond to a set of algorithms or instructions that define the manner in which imputation needs to be performed. Likewise, the filtering technique may correspond to a set of algorithms or instructions that define the manner in which filtering needs to be performed. An example of the techniques for imputation include, but is not limited to, moving averages filter technique. An example of the filtering techniques include, but is not limited to Fast Fourier Transformation. The assigned missing values and the noise and outlier free data may be referred to as the analyzed data. The data pre-processing module <NUM> is configured to provide the analyzed data for the estimation of the moisture content of the gas mixture.

According to a first aspect of the embodiment, the moisture content estimation module <NUM> is configured to determine the thermodynamic properties, heat transfer coefficient (U) and mass transfer coefficient (K) of the gas mixture based on the analyzed data provided by the data pre-processing module <NUM>. The moisture content estimation module <NUM> is further configured to calculate a surface area (A) of the gas cooler <NUM> based on the analyzed data and the determined thermodynamic properties, the heat transfer coefficient (U) and the mass transfer coefficient (K) of the gas mixture. The moisture content estimation module <NUM> is further configured to estimate the moisture content of the gas mixture based on comparison of the calculated surface area (A) of the gas cooler (<NUM>, <NUM>) with an actual (known) surface area (CA) of the gas cooler.

According to a first aspect of the embodiment, the moisture content estimation module <NUM> is configured to calculate the surface area of the gas cooler <NUM> using the analyzed data by balancing/ stabilizing mass and heat transfer at different condensate temperatures in the gas cooler <NUM>. The calculated surface area (A) of the gas cooler <NUM> can be used to estimate the moisture content of the gas mixture at the inlet and outlet of the gas cooler <NUM> in the SHS <NUM>.

According to the first aspect of the embodiment, the moisture content estimation module <NUM> is configured to calculate the surface area (A) of the gas cooler (<NUM>, <NUM>, <NUM>) by determining initial temperatures (initial temperature profiles) of the gas mixture at the inlet and the outlet of the gas cooler <NUM> in the SHS <NUM>. The estimation of the initial temperature profiles of the gas mixture is performed by solving equations (described in <FIG>) for conservation of mass, momentum and energy. The estimation of the initial temperature profiles are performed using computational fluid dynamics finite volume/finite element, CFD, simulations in three dimension. The flow of the gas mixture at the inlet of the gas cooler is predefined. The initial temperature profiles of the gas mixture is used to calculate the surface area (A) of the gas cooler <NUM>.

According to the embodiment, the moisture content estimation module <NUM> is configured to estimate the moisture content of the gas mixture based on comparison of the calculated surface area of the gas cooler (<NUM>, <NUM>, <NUM>) with the actual surface area of the gas cooler (<NUM>, <NUM>, <NUM>). The calculated surface area of the gas cooler is compared with the actual surface area of the gas cooler by determining that the calculated surface area (A) of the gas cooler <NUM> matches with the actual surface area (CA) of the gas cooler <NUM>. In response to the determination, the moisture content estimation module is configured to provide: an estimated flow of the gas mixture at the inlet of the gas cooler and condensate <NUM>, an estimated temperature of the coolant at the outlet and the moisture content of the gas mixture at the inlet <NUM> and the outlet <NUM> of the gas cooler <NUM>.

According to another embodiment, the moisture content estimation module <NUM> is configured to iteratively perform the estimation of the thermodynamic properties, heat transfer coefficient (U) and mass transfer coefficient (K) of the gas mixture using the analyzed data with another predefined value for the flow of the gas mixture at the inlet of the gas cooler, in response to the determination that the calculated surface area (A) of the gas cooler (<NUM>, <NUM>) not matches with the actual surface area (CA) of the gas cooler (<NUM>, <NUM>) the moisture content estimation module. In order to calculate the surface area of the gas cooler <NUM>, a sequence of calculations are performed. The sequence of calculations are formulated in an iterative way to solve a set of equations in a simplified manner. The sequence of calculations are described later with reference to <FIG>.

<FIG> illustrates an exemplary method <NUM> implemented for estimating moisture content of the gas mixture in the SHS <NUM>, according to a second aspect of an embodiment. The methods that are illustrated in <FIG> and <FIG>, as a collection of operations in a logical flow graph representing a sequence of operations that can be implemented in hardware, software, firmware, or a combination thereof. In the context of software, the operations represent computer instructions that, when executed by one or more processors, perform the recited operations. The various method steps performed by each of the data pre-processing module <NUM> and the moisture content estimation module <NUM> for estimating moisture content of a gas mixture in the SHS <NUM> may occur in a sequential manner.

At step <NUM>, the data <NUM> is received by the data pre-processing module <NUM>. The data <NUM> may be received through one or more input devices from user/operator and stored in a memory. The data <NUM> includes measurements (M1-M6, S1) of the SHS related to the gas mixture, a gas cooler and a coolant, and a plurality of parameters related to the gas mixture. The measurements (M1-M6, S1) includes at least real time data from the gas cooler. The plurality of parameters related to the gas mixture comprises parameters for determining thermodynamic properties of the gas mixture. The thermodynamic properties of the gas mixture includes specific heat, heat of condensation, saturated vapor pressure and dynamic viscosity. The gas mixture comprising the flue gas and water vapor.

The measurements (M1-M6, S1) of the SHS related to the gas mixture, the gas cooler and the coolant includes a real time data obtained from the SHS. The real time data is related to pressure, temperature and flow of the gas mixture, the gas cooler and the coolant. The real time data includes the temperature of the gas cooler <NUM> at an inlet and an outlet of the gas cooler, the flow of the gas cooler <NUM> at the outlet, the temperature at an inlet of the coolant and the flow of the coolant at the inlet. The real time data further includes a pressure (M3) at the inlet of the gas cooler <NUM>, pressure (M5) at the outlet of the gas cooler <NUM> and a pump discharge pressure (M6). The plurality of curves comprises Chilton curves, wherein the Chilton curves provide Chilton factor based on Reynolds number of flow, wherein the Chilton factor is utilized for determining the heat transfer coefficient (U) and mass transfer coefficient (K).

At step <NUM>, the received data is analyzed to remove one or more anomalies from the data <NUM>. The received data is processed by assigning/imputing missing values in the measurements (M1-M6, S1) of the SHS and removing noise and outliers in the data <NUM>. The missing values in the measurements (M1-M6, S1) of the SHS are assigned/imputed using known techniques for imputation, such as moving averages filter technique. Noises and outliers are removed from the data <NUM> using known filtering techniques such as Fast Fourier Transformation. The imputed data and the noise and outlier free data may be referred to as the processed data. The analyzed data is provided for the estimation of the moisture content of the gas mixture.

At step <NUM>, the thermodynamic properties, heat transfer coefficient (U) and mass transfer coefficient (K) of the gas mixture are determined using the analyzed data provided by the data pre-processing module <NUM>.

At step <NUM>, a surface area (A) of the gas cooler is calculated based on the analyzed data and the determined thermodynamic properties, heat transfer coefficient (U) and mass transfer coefficient (K) of the gas mixture.

At step <NUM>, the moisture content of the gas mixture at the gas cooler inlet and the gas cooler outlet of the gas cooler <NUM>, <NUM> in the SHS <NUM> is calculated based on comparison of the calculated surface area (A) of the gas cooler (<NUM>, <NUM>) with an actual surface area (CA) of the gas cooler (<NUM>, <NUM>). The calculated surface area (A) of the gas cooler <NUM>, <NUM> can be used to estimate a percentage of the moisture content of the gas mixture at the inlet and outlet of the gas cooler <NUM>, <NUM> in the SHS <NUM>.

<FIG> illustrates an exemplary gas cooler <NUM> of the SHS <NUM> for introducing a coolant, according to a first aspect of an embodiment herein. The gas cooler <NUM> includes a cooler body <NUM> and a plurality of inlets and outlets (<NUM>-<NUM>). The plurality of inlets and outlets includes an inlet <NUM> and an outlet <NUM> of the gas cooler and an inlet 406and an outlet <NUM> of the coolant and a water outlet <NUM>.

The gas mixture enters the gas cooler <NUM> through the inlet <NUM> and simultaneously the coolant enters the gas cooler <NUM> through the inlet <NUM> of the coolant. The gas mixture, as described above, is heated using the ring heater in the sample probe <NUM> and the heat tracer line <NUM> before entering the gas cooler <NUM>. The heated gas mixture exchanges heat with the coolant by conduction through the gas cooler body <NUM>. The gas mixture may exchange the heat with the coolant and the water vapor comprised in the gas mixture loses the heat. The water vapor in the gas mixture starts condensing into a pure/clean liquid. The pure liquid that is saturated may leave through the water outlet <NUM>. The coolant absorbs heat from the heated gas mixture and temperature of the coolant is increased. The coolant that absorbs the heat may leave the gas cooler <NUM> through the outlet <NUM> of the coolant. The gas mixture with a remaining water vapor leaves the gas cooler <NUM> through the outlet <NUM>. Condensation of the water vapor occurs in a presence of non-condensable gases inside the gas cooler <NUM>. The amount of a moisture in the gas mixture at the inlet <NUM> and outlet <NUM> of the gas cooler can be estimated at the moisture content estimation module <NUM> using the sequence of calculations that are formulated to solve a set of equations.

<FIG> and <FIG> illustrate an exemplary method <NUM> depicting a sequence of steps performed for estimating a moisture content of a gas mixture in a Sample Handling System, SHS, according to a second aspect of an embodiment herein. The method <NUM> illustrates steps (<NUM>-<NUM>) representing the sequence of calculations that are formulated to solve a set of equations.

At step <NUM>, saturated water vapor pressures (pv,i and , pv,o) at an inlet <NUM> and an outlet <NUM> of a gas cooler are calculated from given temperatures using Clausius-Clapeyron equation or the equation given below. <MAT> where T is the temperature in Kelvin
The given temperature, could for example, include the temperatures and flows of the gas cooler <NUM>, <NUM>, <NUM> and a coolant comprises: the temperature of the gas cooler <NUM>, <NUM>, <NUM> at the inlet <NUM> and the outlet <NUM> of the gas cooler, the flow of the gas cooler <NUM>, <NUM>, <NUM> at the outlet <NUM>, the temperature at the inlet <NUM> of the coolant and the flow of the coolant at the inlet <NUM>.

At step <NUM>, gaseous (i.e., non-condensable flue gases) vapor pressures at the inlet <NUM> and the outlet <NUM> of the gas cooler are calculated using saturated water vapor pressures (pv,i and pv,o) at the inlet <NUM> and the outlet <NUM> of the gas cooler using a following equation.

At step <NUM>, an amount/ quantities or moles of the water vapor and gases at the outlet <NUM> of the gas cooler is calculated using a flow of the gas mixture at the outlet <NUM> of the gas cooler. The gas mixture comprising gas (flue gas) and water vapor (vapor mixture).

At step <NUM>, a condensate flow (Fc) is calculated by assuming the flow of the gas mixture (Fa, should be greater than exit flow at the outlet <NUM> of the gas cooler) at the inlet <NUM> of the gas cooler using the following equation.

At step <NUM>, amount or quantities or moles of the water vapor and gases at the inlet <NUM> of the gas cooler (Wa) is calculated using the water vapor pressure (pv,i) and gases vapor pressure (pg,i).

At step <NUM>, heat transferred in condensing and cooling of the Fc moles of the water vapor is calculated using a following equation.

At step <NUM>, the heat transferred in cooling the non-condensable gas (flue gas or gaseous) mixture is calculated using a following equation. <MAT> where CPg,a= specific heat of the non-condensable gases at the temperature Ta.

At step <NUM>, the heat transferred in cooling un-condensed water vapor is calculated using a following equation <MAT> and then a total heat transferred to coolant is calculated using a following equation.

At step <NUM>, temperature (Te) at the outlet (<NUM>) of the coolant is calculated by equating the total heat transferred (ΔH) to the coolant temperature rise.

At step <NUM>, mass velocity of the gases and the vapor mixture entering the gas cooler/a heat exchanger with known a cross-sectional area say "CA" is calculated.

At step <NUM>, Reynolds number for the entering gases and the vapor mixture is calculated. Subsequently or simultaneously, the viscosity (µ) of the gas mixture from the temperature (Ta) at the inlet <NUM> of the gas cooler <NUM> is calculated.

At step <NUM>, heat transfer factor (j) from the Reynolds number (Re) is calculated using the plot given in Chilton and Colburn (<NUM>). Alternatively, an approximate function/curve can be used to calculate the heat transfer factor (j) from the Reynolds Number (Re) calculated at step <NUM>.

At step <NUM>, heat transfer coefficient (Colburn, <NUM>) in a gas film (the water vapor and the gases mixture) is calculated using a following equation.

At step <NUM>, rate of diffusion of vapor molecules through the gas film (Chilton and Colburn, <NUM>) is calculated using a following equation.

At step <NUM>, temperature range of the gas cooler (<NUM>, <NUM>, <NUM>) is divided into a ten point grid and a heat transfer coefficient value is assigned to the divided ten points grid of the temperature range of the gas cooler (<NUM>, <NUM>, <NUM>). For assigning a first value in the ten points grid, the temperature range is divided into the ten points for a particular range of temperature. For example, if the temperature range is between <NUM> and <NUM>, then the range is divided as <NUM>, <NUM>. Subsequently, at each temperature (i.e., <NUM>, <NUM>. ) the condensate temperature (tc) is assumed and iterative calculations (from <NUM> to <NUM>) are repeated for a heat balance. If it is balanced or stabilized, then the assumed condensate temperature (tc) is right. If it is not balanced, new value for the condensate temperature (tc) is assumed and from step <NUM> to step <NUM> are repeated.

At step <NUM>, the log mean of the non-condensable gas vapor pressure (pgf) is calculated by assuming a temperature of a condensate surface (tc) using a following equation.

The temperature of a condensate surface tc is assumed based on which pc, pg', pgf are calculated and substituted in equation <NUM>. It shall be noted that tc, pgf are estimated iteratively in the equation (<NUM>) till the balance is reached. That is, the value in the left hand side of the equation equals to the value in the right hand side of the equation.

At steps <NUM> and <NUM>, the left hand side (i.e. rate of heat transfer through gas and condensate films) and the right hand side (i.e. rate of heat transfer through tubes provided inside the gas cooler body <NUM> and coolant film) of the equation (<NUM>) are calculated. As already described, tc and pgf are estimated iteratively in the equation (<NUM>) till the value in the left hand side of the equation (<NUM>) equals to the value in the right hand side. The iteration stops when finally the value in the left hand side of the equation (<NUM>) equals to the value in the right hand side. The value of the rate of the heat transfer through gas and condensate films and the rate of the heat transfer through the tubes of the gas cooler body <NUM> and coolant film are the values at which the iteration stops.

At step <NUM>, a value of the rate of the heat transfer through gas and the condensate films is compared to a value of the rate of the heat transfer through the tubes of the gas cooler body <NUM> and the water film.

At step <NUM>, as a result of comparison it is determined that if the value of the rate of the heat transfer through gas and condensate films is equal to the value of the rate of the heat transfer through the tubes of the gas cooler body and water film. If the values are equal, then the method <NUM> proceeds to step <NUM>. If it is determined that the values are not equal, then the method <NUM> repeats the calculations from step <NUM> to step <NUM>.

At step <NUM>, over-all heat transfer coefficient (U) is calculated by equating the heat transfer through the gas film and latent heat using the following equation.

At step <NUM>, value of the overall heat transfer coefficient (U) calculated at step <NUM> is now assigned as the first value in the grid.

To calculate a surface area (A) of the gas cooler (<NUM>, <NUM>, <NUM>) the parameters tg, tw, Δt, tc, pg, pgf, q, m, Re, K and U may be used. Where 'tg' refers to the non-condensable gas temperature, 'tw' refers to water temperature, 'Δt' refers to temperature difference between the temperature at the inlet <NUM> of the gas cooler <NUM> and the outlet <NUM> of the coolant, and 'tc' refers to the temperature of condensate surface. Where 'pg' refers to non-condensable gas pressure, 'pg'' refers to vapor pressure adjacent to the condensate surface, 'pgf' refers to the log mean temperature of 'pg' and 'pg'', q refers to heat transferred, m refers to the mass flow, 'Re' refers to the Reynolds number, K refers to the mass transfer coefficient, and 'U' refers to over-all heat transfer coefficient. tg, tw, Δt, tc may collectively form the initial temperature profiles or initial temperatures.

For calculation of the surface area of the gas cooler (<NUM>, <NUM>, <NUM>), several temperatures between Ta and Tb across the length of the condenser or the gas cooler (<NUM>, <NUM>, <NUM>), say ten points are identified. The condensate surface temperature (tc) and the overall heat transfer coefficient (U) are calculated by iterating the equation <NUM> of the step <NUM> and equation <NUM> of the step <NUM> at all the <NUM> intervals between Ta and Tb. This results into the following table, Table <NUM> (say Ta is <NUM>°Cand Tb is <NUM>).

The surface area (A) of the gas cooler (<NUM>, <NUM>, <NUM>) is calculated based on the area under a curve (not shown) of "q vs (<NUM>/UΔt)", where q refers to heat transferred, 'U' refers to overall heat transfer coefficient and Δt refers to temperature difference between temperature at the inlet <NUM> of the gas cooler and the outlet <NUM> of the coolant are shown in the Table <NUM> above. Each value of 'q' against each value of 'UΔt' between points <NUM> to <NUM> are shown in the Table <NUM>. A graph (curve) (not shown) can be obtained by combining these values of 'q' against 'UΔt'.

At step <NUM>, the calculated surface area (A) of the gas cooler (<NUM>, <NUM>, <NUM>) at step <NUM> is compared with the actual surface area (CA) of the gas cooler (<NUM>, <NUM>, <NUM>).

At step <NUM>, it is determined whether the calculated surface area (A) of the gas cooler (<NUM>, <NUM>, <NUM>) matches the actual surface area (CA) of the gas cooler (<NUM>, <NUM>, <NUM>). If it is determined that the calculated surface area (A) of the gas cooler (<NUM>, <NUM>, <NUM>) and the actual surface area (CA) of the gas cooler <NUM>, <NUM>, <NUM> matches or almost equal or very close (considerable difference between the CA and C or very less difference), then the method <NUM> proceeds to step <NUM>. Further, the estimated moles of water vapor entering at the inlet of the gas cooler (Wa) and exiting at the outlet (Wb) of the gas cooler are considered for providing the output at step <NUM>. If it is determined that the calculated surface area (A) of the gas cooler <NUM>, <NUM>, <NUM> not matches with the actual surface area (CA) of the gas cooler <NUM>, <NUM>, <NUM>, then the method <NUM> repeat the steps from the step <NUM> to step <NUM>, where, assuming the flow of the gas mixture (Fa, should be > exit flow at the outlet 404of the gas cooler <NUM>) at the inlet <NUM> of the gas cooler <NUM>, the condensate flow (Fc) is calculated using the equation (<NUM>), Fc = Fa - Fb.

At step <NUM>, if the calculated area (A) matches with the actual surface area (CA) of the gas cooler, then an estimated flow of the gas mixture and condensate, an estimated temperature of the coolant at the outlet <NUM> and a percentage of the moisture content of the gas mixture at the inlet <NUM> and outlet <NUM> of the gas cooler <NUM> are provided/assigned as the output <NUM>.

An advantage of the above-mentioned system for estimating the moisture content of the gas mixture in the Sample Handling System (SHS), is to avoid the dependency on requirement of hardware based moisture sensors. Another advantage of the system is to improve the reliability of the gas analyzer readings. Yet another advantage of the system is to enable the estimation of the moisture content by providing additional feature (moisture measurement) and without any additional cost (no need of hardware component) to an existing/conventional Sample Handling System.

Claim 1:
A system (<NUM>) for estimating a moisture content of a gas mixture in a Sample Handling System, SHS (<NUM>), the system (<NUM>) comprising:
a data pre-processing module (<NUM>) configured to:
receive data (<NUM>) comprising measurements (M1-M6, S1) of the SHS related to the gas mixture, a gas cooler and a coolant and a plurality of parameters related to the gas mixture ;
analyze the received data to remove one or more anomalies from the data (<NUM>) and
a moisture content estimation module (<NUM>) configured to:
determine thermodynamic properties, heat transfer coefficient (U) and mass transfer coefficient (K) of the gas mixture based on the analyzed data,
calculate a surface area (A) of the gas cooler based on the analyzed data and the determined thermodynamic properties, heat transfer coefficient (U) and mass transfer coefficient (K) of the gas mixture, and
estimate the moisture content of the gas mixture based on comparison of the calculated surface area (A) of the gas cooler (<NUM>, <NUM>, <NUM>) with an actual surface area (CA) of the gas cooler (<NUM>, <NUM>, <NUM>).