Title of Invention

A METHOD FOR AUTOMATICALLY CONTROLLING PRECISE DOSAGE RATE OF CONDITIONING CHEMICALS FOR A FLUE GAS STREAM INPUT OF ELECTROSTATIC PRECIPITATOR

Abstract

A method for the precise rate of dosage of specified conditioning chemicals and/or their compounds and/or steam to a flue gas stream from coal combustion and/or thermal processors before electrostatic precipitator to optimize the rate of dosage resulting in control and reduction of emission from the stack preventing excess dosage in an economical manner. The method of precise dosage rate of the specified chemicals will be used for online or standalone control dosage using an automatic control system. This method is designed to avoid any excess dosage of the specified chemicals and/or their compounds and thus reduce the emission from the stack economically.

Full Text

FORM 2 THE PATENT ACT, 1970 (39 OF 1970) AND THE PATENTS RULES, 2003 COMPLETE SPECIFICATION (See section 10; rule 13) 1. TITLE OF THE INVENTION 2. APPLICANT (S) a. Name: Ltd. A method for automatically controlling precise dosage rate of conditioning chemicals for a flue gas stream input of electrostatic precipitator. Inventor Trivedi Sanjay N. - Chemithon Engineers Pvt. Bhagwat Sunil S. (Dr.) - University Institute of Chemical Technology, Mumbai Unni Pandamparampath N. - Chemithon Engineers Pvt. Ltd. Phadke Ravindra C. (Dr.) - Chemithon Engineers Pvt. Ltd. b. Nationality: c. Address Indian CHEMITHON ENGINEERS PVT. LTD Shiv Anand-A, 1st Floor 372/374, S. V. Road Goregaon (West) Mumbai 400104 India PREAMBLE TO THE DESCRIPTION COMPLETE The following specification particularly describes the invention and the manner in which it is to be performed DESCRIPTION This present invention generally relates to a method of the precise rate of dosage of specified conditioning chemicals and/or their compounds and steam along with air to a flue gas stream from coal combustion and/or thermal processes before Electrostatic Precipitator in a coal-based thermal process plant to optimize the rate of dosage resulting in control and reduction of emission from the stack in an economical manner and preventing excess dosing of chemicals and steam resulting in reduction of emissions from the stack. This precise dosage rate will be the set point to an automatic control system so as to automatically control the dosage rate. This method is linked to multiple plant operating parameters including boiler load and/or combustion processes and arrives at the optimum dosage rate of chemicals and steam. The predetermined quantity of chemicals and steam dosed before the Electrostatic Precipitator would result in reduction of emissions from the stack. Background & Prior Art In typical combustion processes, fossil fuels like heavy oils, lignite and coal are combusted with air in furnaces, kilns, boilers, etc. producing thermal energy for generating steam for electrical power generation or other thermal processes, used in cement plants, sponge iron plants, paper plants, refineries, etc. and generating flue gases, which consist mainly of ash particles suspended in air (SPM). The contents of the flue gases are dependent mainly on the fossil fuels burnt as well as the combustion efficiency of the system. The flue gas is subjected to processes for removal of ash/particles. Among the various constituents of the flue/exhaust gases the important ~ constituents, which pollute the air, are Suspended Particulate Matter (SPM) and oxides of Sulfur and Nitrogen. These emissions must be removed or reduced from the flue/exhaust gases to reduce the health hazards and be compliant with the emission standards set by regulatory authorities. The flue/exhaust gas emission standards define the levels of SPM and oxides of Sulfur and Nitrogen in the stack for different combustion processes and mandate compliance of that the emissions with the National Ambient Air Quality Standards in the country. The reduction/removal of the suspended particulate matter is usually done using Electrostatic Precipitators (EP) and/or bag fitters. The effectiveness of removal/ reduction of SPM using EP is dependent on the electrical, chemical and physical properties of the SPM and the design of EP. With the emission standards getting stringent and aiming at "zero" emissions, existing EP need retrofitting or augmentation or the properties of the SPM need to be changed by control of moisture and/or by chemical means to reduce the emissions. The objective of the research and development in this field is to reduce and/or remove the SPM in the emission. Electrostatic Precipitation (EP) is a process using electrical forces to separate SPM from flue/exhaust gases. The collection efficiency is effected by the ash and gas properties and operating conditions. In cases where collection is poor, steps are usually taken to modify the EP or gas properties and thereby increase the collection efficiency ot the EP. The most known and widely used technique is to add trace amounts of "Conditioners", to the SPM-air mixture to alter their properties and improve the collection efficiency. The collection of SPM in EP is governed by electrical conductivity of the material being collected. Highly conductive SPM with resistivity of less than 104 ohm-cm can be electrically charged and collected easily in EP. Poorly conductive SPM or highly resistive SPM with resistivity over 1011 ohm-cm exhibit opposite phenomena. The efficient collection in EP is effected by re-entrainment or the back corona phenomenon. As early as 1912 it was discovered that copper converter dust precipitation was considerably enhanced by the presence of Sulfur Trioxide or increased moisture of exhaust gases. The combustion of low Sulfur coal reduces the amount of Sulfur dioxide produced by the combustion process and is often insufficient to produce the quantities of Sulfuric acid required to effectively remove SPM at the EP. In such cases generating Sulfur trioxide extraneously for injection into the flue gases to combine therein with air and water from the flue gas to form sufficient Sulfuric acid to precipitate upon the particles of fly ash and provide the necessary efficiency for EP for removal of SPM from the flue gas is done. In case of fly ash particles from coal-fired boilers, the resistivity of the ash particles is related mainly to the Sulfur and/or alkali metal oxide and/or iron oxide. In case of Sulfur of less than 1% and/or alkali metal oxide of less than 2-3% in coal the resistivity of particles of fly ash is high in the region of 1010 -1013 ohm-cm. It has been observed that the most efficient collection or precipitation of particles occurs when resistivity is about 108 - 1010 ohm-cm. When the particles are in this resistivity range, a balance is achieved between the tendency to have either overcharged or undercharged particles and optimum collection efficiency results. To control the resistivity of the particles various chemicals have been injected into the gas stream. The chemicals, which have been injected into the gas stream, include water, Sulfuric acid, Sulfur trioxide and Phosphoric acid. There are references to chemicals injected into the gas stream and conditioner formed thereby may be found in the following patents : Water - U.S. Patent No.2, 746, 563; Great Britain Patent No. 932, 895; Sulfuric acid - U.S. Patent no. 2, 746, 563, Great Britain No. 932, 895, U.S. Patent No. 2, 602, 734; Sulfur trioxide :U.S. Patent No. 2, 746, 563, Great Britain Patent No. 932, 895, Great Britain Patent No. 933,286 and Phosphoric Acid - U.S. Patent No. 3, 284, 990. U.S. Patent No. 3, 665, 676 describes a conditioner solution comprising an aqueous solution of ammonium sulfates or ammonium bisulfate. Schmidit W.A. (Ind. Eng. Chem. 41, 2428(1949) has explained how acid conditioners such as sulfur trioxide help resistivity problems associated with basic dust such as many types of fly ash from coal-fired power plants, while ammonia is a good additive for acidic fly ash containing high levels of alumina and Silica. Ammonia dosing is also indicted not only for gas conditioning but also for binding the sulfur trioxide in the flue gas for the desulfurisation process stages or formation of ammonium sulfate for use as synthetic fertiliser. Welty A-B in U.S. Patent no. 3, 676, 059 (11.07.1972) describes sulfate control in ammonia flue gas desulfurisation. Exxon Res Eng. Co. in its U.S. Patent no. 1, 469, 340 (06.04.1977) describes ammonia flue gas desulfurisation process. Babacock & Wilcox Co. in its U.S. Patent No. 2, 130, 767 (25.02.1996) describes removal of SOx/NOx/Hg from flue gas by ammonia wet scrubbing using iron chelate catalysts. Gleson R. J. Fieldman P.L. in U.S. Patent No. 4, 525, 142 (25.06.1995) describe process for treating flue gas with alkali injection and electron bean. The process patented is for removing emissions comprising either sulfur oxide or nitrogen oxides or both from the flue gases. Apollo Chem in U.S. Patent No. 4, 042, 348 (16.08.1977) describe a method for conditioning flue gas through an EP wherein use of ammonium bisulfate has been made. The patent also reports that attempts to control resistivity of particles using conditioner such as water, anhydrous ammonia, water and ammonia, sulfuric acid, sulfur trioxide, phosphoric acid has been met with only limited success. The use of ammonia has been described in U.S. Patent 1, 291, 745, 2,356, 717 and use of water and ammonia in U.S. Patent 2,501,435 and 3, 523,407. An Indian Patent bearing no. 194122 describes the use of ammonia vapour as preferred conditioning agent by mixing with air with atleast 1% ammonia and injecting the mixture of gases through flue gas passing through EP to precipitate SPM. This method has specified for flue gas temperature between 140°C to 175°C for a flue gas flow rate between 40 - 50 NM3/sec. for coal having sulfur content ranging between 0.2% - 0.35% and ash more than 40%. An Indian Patent No. 181071 of Chemithon Corporation, U.S.A. describes in detail a method for conditioning flue gas to improve the removal of fly ash by EP by using 4 - 7.5% of conditioning agent. The method also elaborate better conversion methods of SO2 to SO3 and thus give an economical option for effectively using SO3 as the conditioning agent for reducing SPM emission from the stack. None of the patents give any method for the precise dosage rate of the conditioning chemical for reducing the emission of pollutant from the stack. Thus there are no methods for the precise rate of dosage of conditioning chemical agent. It has been observed that the control of emission is dependent on many parameters viz., the constituents of coal and ash generated from it; the operating parameters of the combustion process as well as the variable operating parameters of the E.P. PRESENT SOLUTION FOR THE PROBLEM The present invention provides a method for the precise dosage of chemicals like ammonia and/or its compounds and sulfur and/or its compounds and/or steam independently or a combination of any of the above chemicals for a given coal and ash quality and coal combustion plants multiple operating parameters for optimizing the conditioning chemicals used. The method also takes into account the cost factor of the conditioning chemicals to arrive at the best operating economics. The method also includes the automatic control of the conditioning chemical dosage rate based on the multiple plant operating parameters, which vary from plant to plant including boiler load and SPM emission from the stack to arrive at the optimum dosage rate of conditioning chemicals preventing excess dosage. The dosage rate is predetermined by utilizing an appropriate tool among the various available methods. This dosage rate determined by employing this method will be the set point to the automatic control system. The automatic control system would have the method incorporated based on the annular neural network method so as to arrive at the appropriate dosage rate of conditioning chemicals online or standalone caused by change in the chemical composition of the coal or the important operating parameters of the plant. The predetermined precise dosage quantity of conditioning chemicals dosed before EP would result in reduction of emissions from the stack. The present invention is described as follows wherein Indian coal and ash generated from such coal and coal combustion plants generating electricity and in no way restricts the scope of the inventions. The coal combustion plants are mainly used for generation of electricity; there are instances of furnaces/rotary kilns used by cement and sponge iron plants and coke in blast furnaces in the chemical plants. The different conditioning chemical agents have been used globally for different quality of coal depending on the chemical constitution as well as the electrical properties of the ash generated by the combustion of the coal. The Indian coal is typical and contains sulfur ranging between 0.01% - 1.5%, ash is ranging between 15% - 60% and moisture ranging between 1.00 - 16.00%. The ash generated from these type of coal would contain AI2O3 and/or Si02 in the range of 70% - 95%, alkali metal oxide ranging between 0.3% to 6.0% and sulfur trioxide between 0.005% - 2.5%. Thus the property of ash results in resistivity ranging from 107 to 1014 ohm-cm between operating temperatures in EP ranging between 115 °C to 190 °C. The efficiency of the Electrostatic Precipitator (EP) is dependent on the properties of coal, ash and also depends on the EP parameters like, flue gas flow rate ranging between 120 NMVSec. To 740 NMVSec, temperature of flue gas entering the EP, between 115° C - 190° C, the Specific Collection Area (SCA) of EP, between 71 mVmVsec - 180 mVmVsec and the inlet dust load burden, between 20 gm/NM3 to 96 gm/NM3 in the EP. Thus it was observed that there are many variables depending on which the operation of the EP is based and its efficiency determined. The other criteria for deciding the efficiency of the EP are the coal combustion load or boiler load and the emission norms for SPM stipulated by the regulatory authorities for compliance. The various parameters were analysed and based on the desired reduction of SPM the precise quantity of the conditioning chemicals were dosed. Ammonia dosage would be between 2 kg/hr to 50 kg/hr. per EP pass; steam dosage would be between 50 kg/hr to 1500 kg/hr between 120°C - 150°C and sulfur trioxide dosage would be between 30 kg/hr to 500 kg/hr. The conditioning chemicals viz. ammonia and sulfur trioxide are mixed with air before dosing. The quantity of the conditioning chemicals viz. ammonia in ammonia air mixture would be between 15 ppm to 70 ppm or 0.5% to 6% v/v and that of sulfur trioxide in sulfur trioxide air mixture would be between 10 ppm to 70 ppm or 1% to 6% w/v. The present solution provides a method for automatic controlling precise dosage rate of conditioning chemicals for a flue gas stream before the Electrostatic precipitator (EP) in a thermal process plant, for reducing emission of suspended particulate matter emission from the stack, comprising: A controller coupled to a plurality of injection devices for injecting conditioning chemicals, said injection devices coupled to a flue gas stream to be fed to an Electrostatic precipitator in response to an optimal dosage rate generated by said controller; Said controller comprising a neural network estimator trained to generate optimal dosage rate in response to a plurality of neural net input parameters; Said neural net input parameters comprising of: Amounts of said conditioning chemicals including Ammonia and/or its compounds, sulphur and/or its compounds, steam and air in combination or independently; Said Electrostatic precipitator parameters including flue gas flow rate, temperature and humidity, specific collection area and inlet dust load; Coal parameters including sulphur, moisture, and ash content; said ash further including alkali metal oxide; alumina and/or silica and sulphur trioxide; Electrostatic precipitator flue gas output containing desired suspended particulate matter (SPM). SUMMARY OF INVENTION: A method of the precise rate of dosage of specified conditioning chemicals and/or their compounds and/ or steam to a flue gas stream from coal combustion and/or thermal processors before electrostatic precipitator to optimize the rate of dosage resulting in control and reduction of emission from the stack preventing excess dosage in economical manner. The method of precise dosage rate of the specified chemicals will be used for online or standalone control dosage using an automatic control system. This method is designed to avoid any excess dosage of the specified chemicals and/or their compounds and thus reduce the emission from the stack economically. List of Drawings There is one drawing as Fig.l included which gives the flow diagram of ammonia &/or steam and /or sulfur trioxide dosage system for the precise dosage of the specified conditioning chemicals and/or their compounds and/or steam to a flue gas stream from coal combustion and/or thermal processors before electrostatic precipitator DESCRIPTION OF INVENTION The selection of the conditioning chemicals as well as steam for dosing and the quantities required to be dosed for reducing the SPM emission from the stack to the desired level will depend on the various variable parameters of coal, ash and the E.P. as well as the SPM emissions norms required for compliance. The simultaneous and independent dosage of ammonia and/or steam and/ or sulfur trioxide is an effective method for reducing the Suspended Particulate Matter (SPM) emission. This method of precise dosage of either of these conditioning chemicals is a very flexible method for varying coal/ash quality as well as for various variable operational parameters of the EP. The method of conditioning of the flue gases will depend upon the conditioning chemicals agents and would consist of following steps: Simultaneous Ammonia and/or steam and/or Sulfur trioxide Dosage System: a. Source of ammonia gas : The ammonia gas is obtained from the liquefied gas stored under pressure in gas cylinders or storage tanks by de-pressuring and/or spraying warm water on the cylinder for evacuating the ammonia gas. Ammonia gas is generated from the storage tank or by passing liquefied ammonia through a vaporizer heated by electrical / or steam heaters. The ammonia gas flow from the appropriate source will be controlled at constant pressure through pressure and flow control systems. The ammonia gas is then piped to 'an air dilution system' at the predetermined and precise dosage rate depending of the main variable parameters like boiler load and/ or EP power for a given coal/ash quality. The quantity of ammonia can be varied automatically depending on the variation in any of the variable parameters and/or the quality of coal used in the combustion process. b. Ammonia Air Mixture The ammonia gas is piped from the generation system to the air dilution and mixing system and upto the injection point. Air from a blower is used to dilute ammonia gas. The ammonia-air mixture having concentration of ammonia in air between 0.5% to 6% (v/v) depending on the plant operating parameters is piped to the injection point. c. Ammonia-Air mixture Injection before the EP The Ammonia-air mixture is injected into the inlet duct through an injector assembly consisting of nozzles with orifices. The number of nozzles would depend upon the dosage rate depending on the variable parameters of the plant. The injection assembly is typically located at the entry to EP between the air pre-heater and the EP. The nozzles are installed to establish co-current dosage of ammonia-air mixture with the flue gas flow for obtaining optimum results. Steam Injection The steam is injected into the inlet duct through an injector assembly consisting of nozzles with orifices. The number of nozzles would depend upon the dosage rate of steam which would depend upon the variable parameters of the plant especially the temperature of flue gases in the EP. The injection assembly is typically located at the entry to EP between the air pre-heater and the EP. The nozzles are installed to establish co-current dosage of steam with the flue gas for obtaining optimum results. Sulfur Trioxide Dosage System a) Sulfur Melter Sulfur at normal ambient temperatures is a solid and available in prilled granular or lump form. This Sulfur is melted in a steam heated steel melter and at a predetermined dosage rate is fed to the Sulfur burner. b) Sulfur Burner The Sulfur burner is a vessel where molten sulfur is combusted at a predetermined rate with a predetermined quantity of air to convert Sulfur to mainly sulfur dioxide and the combustion gases exit the burner at between 600 - 750°C. The hot gas mixture is cooled to about 400 - 435°C and passes to a catalytic converter for conversion of Sulfur Dioxide (SO2) to Sulfur Trioxide (so3). The combustion gases exit the burner at about 700°C The hot gas mixture is cooled to about 425°C before it flows to the catalytic converter for optimum conversion of SO2 to SO3. c) Catalytic Converter The catalytic converter converts 95% or higher of SO2 to SO3 over catalysts like oxides of vanadium. The hot SO3 air mixture is piped to the injection point. The SO3 gas temperature is always kept at higher than the air dew point. d) Injection of Sulfur Trioxide The SCb-air mixture is injected at the entry to EP in the duct between the air pre-heater and EP. The SO3 gas is injected using an injection assembly consisting of nozzles with predetermined orifice diameters co-current to the flue gas flow. The SO3 in air concentration w/v can range from 1.0% - 6%. e. Automatic Control System The entire operation of the ammonia and/or steam and/ or injection sulfur trioxide is based on the predetermined precise dosage rate of the same based on the important variable parameters of the coal, ash and operation of the EP and plant. The method used for the precise dosage rate is an integral or stand alone part of the control system, for optimizing the quantity of ammonia and/or sulfur trioxide and/ or steam required for a given set of operating conditions of the plant. The precise dosage rate will prevent excessive dosage and provide the best cost economics for a given set of operating conditions for reducing the Suspended Particulate Matter (SPM) emissions from the present level to the desired limit. The flow diagram of the injection system described above is given in fig.l. The associative property of artificial neural networks and their inherent ability to "learn" and "recognize" highly non-linear and complex relationships finds them ideally suited for a wide range of application in designing; chemistry; engineering; bio technology; drug designing, etc. The neural network has been successfully employed in solving problems in areas such as fault diagnosis, dynamic modeling, designing and control of chemical and biochemical processes. It has also been used in the area of Quantity Structure Property Relationships (QSPRs). Neurons are the building blocks of the neural network which are connected through weights. Inputs and outputs of a neuron are related using transfer function of the neuron. The weights can be obtained using different optimization algorithms, and this process of evaluating weights is known as the training of the network. The data is divided into three sets. One set of data is used for training the network. A second set served as validation set, while last set served as the testing set. All inputs and outputs are scaled linearly using below equation: Y = fl(7-ymin) , h Ymax-Ymiin Where Y is the input or output value, Y is the scaled value and Ymin and Ymax are minimum and maximum of Y. a And b are the variables, which are decided on the basis of required range of the scaled inputs or outputs. The optimal network is determined by performing the training with different configurations and transfer functions. Different optimization algorithms such as Standard Backpropogation, Scaled Conjugate Gradient, Partial recurrent network, self-organising maps, Auto-associative networks, Time delay network, radial basis functions etc. with and without batching are employed to arrive at the optimum structure and weights of the network. Pruning algorithms include Magnitude based pruning and Skeletonization. Various transfer functions used include Logistic Sigmoid, Hyperbolic tangent. The most suitable architecture was decided on the basis of Average Quadratic Error (AQE), Mean Squared Error (MSE) and Shibata Criterion (SC). The input parameters chosen for this network include the velocity of the gases, the size of the EP and its features of design, the nature and amount of additives to the gases, the composition of the coal used, the amount of air used, the composition of the gases, temperature of operation etc., and the output parameters are the load of the boiler and the reduction desired in the SPM emissions from the flue gases from the existing level. The Automatic Control System would analyze the input and output data and would provide a precise rate of dosage of the desired conditioning chemicals for obtaining the output results of SPM emission. Ammonia and/or Steam Dosage System This method of simultaneous dosage of ammonia and/or steam can be used without sulfur trioxide. The selection and the applicability of this method would depend on different parameters viz. quality of coal/ash and EP conditions. In case of the temperature of the flue gases in the inlet of the EP range between 140°C - 185°C, injection of steam in quantity ranging from 50 kg - 1,500 kg @ 5 -6 kg/cm2 pressure is required for appropriations of the conditioning chemicals dosed so that adequate quantity of moisture is available in the flue gas for the conditioning chemicals to react with the dust in the flue gases. The method of precise rate of dosage determination and the quantity of the chemical conditioning agent would be identical as earlier elaborated. The method in which ammonia and/or steam is dosed would have following steps and the individual equipment required for the same are described in detailed above: a. Source of ammonia gas b. Ammonia Air Mixture c. Ammonia-Air mixture Injection before the EP d. Steam Injection e. Control System Sulfur Trioxide Dosage System This method of independent dosing of sulfur trioxide can be used without ammonia and/or steam dosing. The utilization of this method would depend on different parameters viz. quality of coal/ash and EP conditions and the outlet dust burden required. The method in which sulfur trioxide is dosed would have following steps and the individual equipment required for the same are described in detailed above : a) Sulfur Melter b) Sulfur Burner c) Catalytic Converter d) Injection of Sulfur Trioxide e) Control System The method of predetermined dosage rate will precisely predict the quantity of the conditioning chemicals viz. ammonia; and/or sulfur trioxide, and/or steam required for the reduction of SPM emission from the existing levels to the desired level so as to meet the emission norms stipulated by the regulatory authorities. This method of precise dosage rate has been successfully demonstrated in various plants with varying capacity of flue gas flow rates as well as variation in different variable operating parameters of the plant. The predetermined dosage rate and the actual dosage rate observed for the desired SPM emission reduction in the most economical manner from the stack have matched and has proven beyond doubt that the method for ease of operation has proved beyond any doubt the effectiveness of the method invented to obtain the precise conditioning chemicals dosage rate for reducing SPM emissions in the most economical manner and preventing any excess dosage of the conditioning chemicals. The present investigation is illustrated by following non-limiting examples of method of dosage at precise rate of ammonia and/or sulfur trioxide dosing; a method of ammonia and/or steam dosing and method or sulfur trioxide dosing. Example No. 1 The coal, ash and the parameter of the electrostatic precipitator for a coal-fired boiler were as follows: Coal: Ash - 42% ; Sulfur - 0.48%; Moisture -11% Ash : AI2O3 and Si02 - 88.7%; Alkali Metal Oxides - 2.02%; Sulfur trioxide -0.43% EP : Flue Gas Flow Rate - 360 NM3/sec. Temperature - 144°C Specific Collection Area -140 m2/m3/sec. Inlet Dust Load - 81.20 g/NM3 The above data was analyzed for deriving the precise dosage rate of conditioning chemicals for reduction of SPM to less than 75 mg/Nm3. The method of dosing conditioning chemicals viz. ammonia and sulfur trioxide described above was used and on dosing ammonia at the rate of 3.5 kg/hr. and sulfur trioxide at the rate of 40 kg/hr., was able to reduce the emission from 450 mg/Nm3 before dosing of conditioning chemicals viz. ammonia and sulfur trioxide to 45 mg/Nm3 after the dosage of the quantities stated above. Example No. 2 The coal, ash and the parameter of the electrostatic precipitator for a coal-fired boiler were as follows: Coal: Ash - 40% ; Sulfur - 0.5%; Moisture -10% Ash : AI2O3 and Si02 - 79.3%; Alkali Metal Oxides - 3.2%; Sulfur trioxide -0.3% EP : Flue Gas Flow Rate - 203 NM3/sec. Temperature - 150°C Specific Collection Area - 96 m2/m3/sec. Inlet Dust Load - 51.40 g/ NM3 The above data was analyzed for deriving the precise dosage rate of conditioning chemicals for reduction of SPM to less than 140 mg/Nm3. The method of dosing conditioning chemicals viz. ammonia and steam described above was used and on dosing ammonia at the rate of 15 kg/hr. and steam at the rate of 50 kg/hr. was able to reduce the SPM emission from 450 mg/Nm3 before dosing of conditioning chemicals viz. ammonia and steam to 125 mg/Nm3 after the dosage of the quantities stated above. Example No. 3 The coal, ash and the parameter of the electrostatic precipitator for a coal-fired plant were as follows: Coal: Ash - 41% ; Sulfur - 0.40%; Moisture -19% Ash : AI2O3 and Si02 - 89.08%; Alkali Metal Oxides - 4.35%; Sulfur trioxide - 24 0.15% EP : Flue Gas Flow Rate - 674 MM3/sec. Temperature - 145°C Specific Collection Area -140 m2/ni3/sec. Inlet Dust Load - 58 g/ NM3 The above data was analyzed for deriving the precise dosage rate of conditioning chemicals for reduction of SPM to less than 50 mg/Nm3. The method of dosing conditioning chemicals viz, sulfur trioxide described above was used and on dosing sulfur trioxide at the rate of 430 kg/hr., was able to reduce the SPM emission from 175 mg/Nm3 before dosing of conditioning chemicals viz. sulfur trioxide to 50 mg/Nm3 after the dosage of the quantities stated above. WE CLAIM: 1. A method for automatic controlling precise dosage rate of specified conditioning chemicals and/or their compounds mixed with air , steam to a flue gas stream from coal combustion and/or thermal process before the Electrostatic precipitator (EP) in a coal-based thermal process plant, comprising: A controller coupled to a plurality of injection devices for injecting conditioning chemicals, said injection devices coupled to a flue gas stream to be fed to an Electrostatic precipitator in response to an optimal dosage rate generated by said controller; Said controller comprising a neural network estimator trained to generate optimal dosage rate in response to a plurality of neural net input parameters; Said neural net input parameters comprising of: Amounts of said conditioning chemicals including Ammonia and/or its compounds, sulfur and/or its compounds, steam and air in combination or independently; Electrostatic precipitator parameters including flue gas flow rate, temperature and humidity, specific collection area and inlet dust load; Coal parameters including sulfur, moisture, and ash content; said ash further including alkali metal oxide; alumina and/or silica and sulfur trioxide; Electrostatic precipitator flue gas output containing desired suspended particulate matter (SPM). 2. A method as claimed in Claim 1 wherein said neural net input parameter preferably further comprising of combustion load or boiler load factor 3. A method as claimed in Claim 1 wherein coal in coal combustion is having sulfur between 0.01% and 1.5%. 4. A method as claimed in Claim 1 wherein the coal contains ash between 15% and 60%. 5. A method as claimed in Claim 1 wherem the coal contains moisture between 1.00%-16.00% 6. A method as claimed in Claim 1 wherein ash from coal used in coal combustion is having alkali metal oxides between 0.3% and 6.00%. 7. A method as claimed in Claim 1 wherein ash from coal used in coal combustion is having alumina and/or silica between 70% - 95% 8. A method as claimed in Claim 1 wherein ash from coal used in coal combustion is having sulfur trioxide between 0.005% - 2.5% 9. A method as claimed in Claim 1 to 8 wherein the flue gas having temperature between 115°C to 190°C. 10. A method as claimed in Claim 1 to 9 wherein the flue gas flow rate in EP is 120 NMVSec. to 740 NMVSec. 11. A method as claimed in Claim 1 to 10 wherein flue gas humidity is from 6% to 10%. 12. A method as claimed in claim 1 to 11 wherein the inlet dust burden in the flue gas is between 20 gm/NM3 to 96 gm/NM3. 13. A method as claimed in claim 1 to 12 wherein the Specific Collection Area of the EPis between 71 mVmVSec. to 180 mVmVSec. 14. A method as claimed in claim 1 to 13 wherein ammonia dosage rate is 2 kg/hr. to 50 kg/hr. per EP pass wherein ammonia concentration in the flue gas is between 15 ppm to 70 ppm and/or sulfur trioxide dosed in the flue gas is between 30 kg/hr to 500 kg/hr and its concentration in flue gas stream is from 10 ppm to 70 ppm. 15. A method as claimed in Claim 1 to 14 wherein steam between 120°C to 150 °C is dosed into the flue gas at the rate of 50 kg/hr to 1500 kg/hr. 16. The method for as claimed in Claim 1 to 15 wherein the ammonia in ammonia-air mixture is preferably 0.5% - 6% w/v and/or sulfur trioxide in sulfur trioxide air mixture is preferably 1% to 6% 28 w/v. 17. The method as claimed in Claimed 1 to 16 wherein the control of the conditioning chemicals from control system is by coal combustion plant load and SPM emission in addition to the other operating parameters of the coal combustion plant. 18. The method for as claimed in Claim 1 to 17 wherein ammonia and/or sulfur trioxide air-mixture dosage is predetermined to reduce the SPM emissions from the stack in an economical and safe manner, in the range of 13 mg/NM3 to 140 mg/NM3 of flue gases depending on the coal; ash and other coal combustion plant operating parameters. Dated this 08th of July 2005.

Documents:

862-mum-2005-abstract(23-04-2005).doc

862-mum-2005-abstract(23-04-2005).pdf

862-mum-2005-abstract-provisional.doc

862-mum-2005-abstract-provisional.pdf

862-mum-2005-cancelled pages(23-04-2007).pdf

862-mum-2005-claims(granted)-(23-04-2005).doc

862-mum-2005-claims(granted)-(23-04-2005).pdf

862-mum-2005-claims-complete.doc

862-mum-2005-claims-provisional.doc

862-mum-2005-claims-provisional.pdf

862-mum-2005-claims.pdf

862-mum-2005-correspondence(31-01-2007).pdf

862-mum-2005-correspondence(ipo)-(07-09-2006).pdf

862-mum-2005-correspondence-received-ver-140206.pdf

862-mum-2005-correspondence-received-ver-141205.pdf

862-mum-2005-correspondence-received-ver-180705.pdf

862-mum-2005-correspondence-received-ver-310107.pdf

862-mum-2005-correspondence-received-ver-311006.pdf

862-mum-2005-descripiton (complete).pdf

862-mum-2005-descripiton (provisional).pdf

862-mum-2005-drawings.pdf

862-mum-2005-form 1(21-07-2005).pdf

862-mum-2005-form 18(14-02-2006).pdf

862-mum-2005-form 2(granted)-(23-04-2005).doc

862-mum-2005-form 2(granted)-(23-04-2005).pdf

862-mum-2005-form 26(18-07-2005).pdf

862-mum-2005-form 3(18-07-2005).pdf

862-mum-2005-form 9(14-12-2005).pdf

862-mum-2005-form-1.pdf

862-mum-2005-form-18.pdf

862-mum-2005-form-2-complete.pdf

862-mum-2005-form-2-provisional.doc

862-mum-2005-form-2-provisional.pdf

862-mum-2005-form-26.pdf

862-mum-2005-form-3.pdf

862-mum-2005-form-9.pdf

abstract1.jpg