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    • 专利摘要:

    公开号:FI20185222A1
    申请号:FI20185222
    申请日:2018-03-09
    公开日:2019-09-10
    发明作者:Reijo Lylykangas
    申请人:Vocci Oy；
    IPC主号:
    专利说明:

    Method for producing heat in an energy plant
    The invention relates generally to the generation of heat in boilers, gas turbines and diesel power plants and similar power plants. The invention also relates to the reduction of exhaust emissions from power plants.
    In particular, the present invention relates to a method for producing thermal energy from a hydrocarbonaceous fuel according to the preamble of claim 1. According to such a method, the fuel is combusted at an elevated temperature, the heat from the combustion is recovered and the combustion exhaust gases and soot particles are purified by catalytic exhaust combustion.
    The invention also relates to a process according to the preamble of claim 18 for the catalytic purification of exhaust gases containing nitrogen oxides and carbon monoxide, hydrocarbons and soot particles from power plants using hydrocarbon silicon fuel.
    background information
    Emissions of nitrogen oxides (NOx), carbon monoxide (CO), carbon dioxide (CO2) and hydrocarbons (VOC) from energy production are being controlled worldwide to curb the greenhouse effect. In Europe, a number of directives have been adopted to this end for boilers, process equipment, fireplaces, etc. They set emission limits for greenhouse gases, either directly or through efficiency or emission limits. In the United States, EPÄ and CARB have set limits for nitrogen oxides and hydrocarbons, in part by compound. A similar trend is underway in China. For example, in Beijing, the NOx limit value for boilers is set at 30 mg / m 3 and for CO at 80 mg / m 3 . The limits are so strict that they cannot be achieved with current conventional thermal incinerators without after-treatment. The same sharply tightening trend will continue in other industrialized areas of China.
    Even before the above-mentioned emission limits have stabilized, Beijing has set a target30 to set even stricter limits. For N0x, the target is zero or near zero emissions and
    In terms of CO, it is substantially below the previous limit.
    20185222 prh 09 -03- 2018
    Commercial UltraLow NO X and NoNO x burner manufacturers use flue gas recirculation, aqueous emulsions, and gas preheating in their burners that effectively mix the above technologies instead of flue gas aftertreatment. Despite the name of the burner NoNO x , no manufacturer of the thermal burner has had access to zero NO X - access5. The lowest value found in the reports is 6 ppm with an O 2 concentration of 3%.
    Another option is flue gas cleaning. Selective catalytic and non-catalytic reducing agents (Selective Catalytic Reduction, hereinafter abbreviated as “SCR”, and Selective Non-Catalytic Reduction, “SNCR”) are commonly used to remove nitrogen oxides.
    At its best, catalytic SCR achieves a degree of purification of more than 90% at a temperature of about 350 ° C. In its reports, EPÄ reports an average NOx conversion of SCR of 85%. Non-catalytic SNCR equipment achieves about 20% lower cleaning efficiency. Their use has been targeted at diesel vehicles.
    However, SCR equipment requires a separate reducing agent, urea or ammonia and their dosing equipment, which incurs significant investment and operating costs. Urea decomposes in the catalyst into ammonia (NH 3 ) and carbon monoxide (CO). Ammonia and urea are transported and stored as aqueous solutions. The ammonia content is 27% and the urea content is 32%. Ammonia is a very toxic gas. The NO x emission level achievable with an SCR plant is about 7-30 ppm. In addition, CO emission limits require a separate oxidation catalyst. The use of ammonia as a reducing agent is based on its ability to selectively reduce NOx in a lean gas mixture.
    The high cost of SCR technology is caused by the ammonia (NH 3 ) or urea required for selective reduction in addition to the reducing agent and expensive storage, dosing, heat exchanger and reduction equipment. In addition, the need for replacement of the SCR catalyst has been estimated by EPÄ to be 3 years. In SRC catalysts, the most common active substance, i.e. the catalyst, is vanadium pentoxide (V 2 Os), which is more sensitive to poisoning than precious metals. The SCR catalyst is large in size because of its low turnover, namely 10,000-20.00001 / h. With precious metal catalyst30, the exchange is 5 to 10 times larger, ie the size of the precious metal catalyst is about one-fifth to one-tenth of the SCR catalyst.
    20185222 prh 09 -03- 2018
    Other weaknesses of the SCR catalyst include NH 3 leaks (2-5 ppm) and the risks of NH 3 toxicity during handling and transport. Replacement of the predominantly toxic SCR catalyst (V2O5) with, for example, non-toxic zeolites is required, especially in the USA.
    In addition, the limitations of catalytic combustion are the so-called catalyst toxins which must not be contained in the exhaust gas. The most important of these are organosilicon, heavy metal and phosphorus compounds. They permanently deactivate the catalysts. Sulfur compounds do not damage the platinum-activated catalyst, but the sulfuric acid resulting from the reactions can concentrate on the surfaces of the heat exchanger at temperatures slightly above 100 ° C, causing corrosion.
    Description of the invention
    The object of the present invention is to eliminate at least some of the problems of the prior art and to provide a completely new solution for the thermal production of thermal energy from hydrocarbon fuel and for the catalytic purification of exhaust gases containing nitrogen oxides and carbon monoxide, hydrocarbons and soot particles.
    In the first embodiment of the invention, thermal energy is produced in two units, whereby thermal energy is first produced in the power plant by burning a hydrocarbonaceous fuel. Heat is recovered in a heat exchanger, for example. The exhaust gases from the combustion are fed with fuel and air to form a gas mixture, and the gas mixture thus obtained is subjected to catalytic combustion, which is carried out at a high temperature. By carrying out the combustion in the presence of a catalyst under reducing and oxidizing conditions at a temperature of at least 600 ° C, the nitrogen oxides in the flue gases are reduced and the carbon monoxide, hydrocarbons and carbon black particles are oxidized. The heat from the catalytic combustion is also recovered.
    In another embodiment of the invention, the exhaust gases of a power plant are led to an exhaust gas burner, where the gases are subjected to catalytic oxidation and reduction to reduce the NOx, CO, VOC and particulate concentrations of the exhaust gases and to simultaneously produce thermal energy.
    20185222 prh 09 -03- 2018
    More specifically, the solution according to the invention is mainly characterized by what is set forth in the characterizing parts of the independent claims.
    The present invention provides significant advantages.
    As stated above, neither thermal combustion nor current flue gas cleaning methods can produce the pure thermal energy that is already being demanded in Beijing. However, the object can be achieved with the solution according to the present invention, in which the NOx, VOC, CO and particulate emissions of the exhaust gases of already operating boilers, diesel and gas turbine power plants can be reduced to near zero even with the catalytic exhaust burner. At the same time, small soot particles produced by oil and gas boilers and diesel power plants can also be burned.
    Thus, with the present solution, NOx compounds can be reduced to a residual content of less than 1 ppm, and CO and VOC compounds can be oxidized to a residual content of less than 2 ppm. Small soot particles can also be burned in an exhaust gas burner at a temperature of 600 ° C or above. The most preferred operating temperature range for the burner is 850-1000 ° C. In this area, soot particles also burn quickly.
    Simultaneous energy production is made possible by the use of flue gas from a thermal boiler, turbine or diesel power plant, etc. as a cooling and heat transfer medium in catalytic combustion. In this case, the inert thermal mass of the exhaust gases is utilized in the combustion for temperature control and heat transfer. The flue gas can be used to keep the temperature within the desired range, preferably between 850-1000 ° C.
    With the present solution, which differs from other cleaning methods, it is possible to increase the thermal energy production capacity of a thermal boiler by up to 60%.
    The exhaust gas burner can be added to all energy production equipment with low sulfur emissions and particulate emissions and without so-called catalyst poisons. In contrast, the amount of NOx, CO and VOC emissions from energy sources is practically irrelevant.
    The afterburner also burns, for example, small soot particles produced by oil boilers and diesel power plants. Unless there is a storage POC catalyst in connection with the catalysts, or
    20185222 prh 09 -03- 2018 filter, it is advantageous to provide an intermediate space before the heat recovery piping, in which the particles have time to burn before the energy recovery.
    The exhaust gas burner can also be used to solve the emissions of even the most polluting5 energy-producing equipment in use to the level of the new, more stringent requirements.
    In principle, an exhaust gas burner can be used to clean all types of gases containing NOx, CO and VOC emissions by connecting the burner to a boiler or heat exchanger, as the catalytic combustion operates below the LEL limit. In this case, there is no safety risk similar to that of thermal combustion boilers, which have caused fatal accidents in the combustion of VOCs.
    As the amount of gaseous emissions, in particular the amount of gaseous emissions, is of little importance for the operation and cleaning result of the exhaust burner, freedoms can be allowed for the control of the primary energy source 15 and the choice of equipment. Boilers do not require expensive lowNOx or ultralowNOx burners and the air to fuel ratio can be optimized for maximum power. Diesel engines do not require exhaust gas recirculation (EGR) or very lean blends to reduce NOx emissions, etc.
    The exhaust burner is suitable for e.g. operating energy plants that do not meet the emission requirements of ever-tightening standards. Investments to reduce emissions are often worthwhile because plants are long-lived and require large investments. Another target is new facilities.
    In the following, the present technology will be examined in more detail by means of a detailed explanation with reference to the accompanying drawings.
    Fig. 1 shows a process diagram of one embodiment, Fig. 2 shows a process diagram of a second embodiment, Fig. 3 shows a process diagram of a third embodiment, and Fig. 4 shows a process diagram of a fourth embodiment.
    In the present context, “energy plant” means in particular thermal energy, i
    20185222 prh 09 -03- 2018 thermal energy, a combustion plant that produces energy from hydrocarbon-containing fuel by means of boilers, diesel turbines or gas turbines.
    “Carbonaceous fuel” in the first application means a fuel that contains, but is not necessarily limited to, organic compounds of carbon and possibly hydrogen, such as hydrocarbons. In addition to hydrocarbons, the fuel may contain oxygen-containing compounds such as ethers, esters and alcohols. Examples of carbonaceous fuels according to the first application are fuels derived from fossil raw materials, such as oils, petrol, diesel and natural gas.
    "Carbonaceous fuel" in another embodiment further means a fuel containing carbon compounds consisting primarily of alcohol (hydroxy) groups, ether groups or ester groups, or combinations thereof, for example, hydrocarbon compounds substituted with these groups. These fuels include various biofuels produced from biomass, such as lignocellulose, vegetable oils and animal fats, crops
    The terms 'CO' and 'VOC emissions' and 'NOx emissions' and 'soot particulate emissions', respectively, refer to the amount (in mass) of CO, VOC and NOx and soot particles contained in the exhaust gases.
    The present technology generally provides a solution for treating exhaust gases and generating energy with a catalytic exhaust burner. The method can be applied to both heat generation and exhaust gas cleaning, as described in more detail below.
    In the process, additional air and fuel are fed to the exhaust gas generated by thermal combustion to produce the gas mixture required for catalytic combustion, after which the gas mixture is introduced into a catalytic combustion zone for combustion. The heat from the combustion is recovered. As a result of the combustion, CO, VOC, NOx and soot particle30 emissions are significantly reduced in the catalytic combustion exhaust gases.
    In one application, the exhaust gases, fuel, and air are mixed together to produce a homogeneous gas mixture.
    20185222 prh 09 -03- 2018
    In this application, additional air and fuel can be supplied to the exhaust gas burner and their supply is controlled by post-catalyst temperature and linear oxygen sensors according to the need for the air / fuel ratio required by each catalyst.
    In order for the reactions described below to take place, enough fuel is preferably added to the exhaust gas to achieve a rich or stoichiometric mixture ratio. In the former, only the reduction of NOx to nitrogen (N 2 ) and oxygen (O 2 ) takes place, and in the latter, in addition, the oxidation of CO and VOCs to carbon dioxide (CO 2 ) and water (H 2 O) also takes place.
    When supplying the rich mixture, a second catalyst is preferably used, in which case it is provided with the additional air supply required by the lean mixture. Separate oxidation and reduction steps achieve the best results.
    When it is desired to produce the maximum amount of clean energy, then in addition to fuel, air must also be injected into the flue gas. In order to prevent the formation of nitrogen oxides in the afterburning, the temperature should preferably be limited to about 1000 ° C. This solution, which differs from other cleaning methods, makes it possible to increase the thermal energy production capacity of a thermal boiler by up to 60%, as described in more detail below.
    In one application, the exhaust gases, fuel, and air are mixed together in nested shredded supply lines and a static mixer to form a uniformly mixed gas mixture.
    A static mixer can be used to ensure the homogeneity of the gas mixture, which is particularly advantageous to ensure uniform combustion.
    In one application, the catalytic combustion is performed under reducing and oxidizing conditions, respectively, in one or more steps.
    In one application, the gas mixture is subjected to catalytic combustion in a three-way catalyst to an oxidation and reduction catalyst. In this case, the gas mixture can be combusted, for example, in a three-way catalyst with a stoichiometric oxygen / additional fuel ratio.
    20185222 prh 09 -03- 2018 for the oxidation of unburned CO and VOCs and for the reduction of NOx emissions and for the oxidation of soot particles.
    When incinerated at temperatures above 600 ° C, the soot particles burn at the same time.
    Alternatively, in a two-part catalyst, in the reduction section, the rich mixture reduces NOx emissions to nitrogen (N 2 ) and oxygen (O 2 ) and oxidizes most of the CO and VOC emissions to carbon dioxide (CO 2 ) and water (H 2 O).
    With additional air, the gas mixture is then made lean and then the mixture passes through an oxidation catalyst. It oxidizes the remaining CO and VOC emissions. In the next heat transfer stage, the heat energy generated is utilized in water, for example by means of welded finned tube coils, after which the exhaust gas leaves the boiler into the chimney, if necessary with the aid of a suction fan.
    In one application, the gas mixture is first combusted in an oxidation and reduction catalyst with a rich supplemental fuel / oxygen mixture to reduce nitrogen oxides and a lean supplemental fuel / oxygen mixture to oxidize CO and VOCs and soot particles.
    The reaction chain in reducing noble metal catalysts undergoes mainly steam reforming and water gas transfer reactions:
    H 2 O + HC -> H 2 + CO and H 2 O + CO -> H 2 + CO 2 and onwards
    H 2 + NO X -> N 2 + H 2 O.
    Some of the reactions are direct oxidation and reduction reactions.
    Catalytic combustion takes place below the lower explosion limit (LEL) at all times. The fuel can often be the same as in the primary energy generator.
    20185222 prh 09 -03- 2018
    If the flue gas temperature before catalytic afterburning drops below 250 ° C and the fuel is natural gas or other high temperature fuel, then the catalyst structure should be a recuperative or regenerative heat exchanger, e.g. or ethanol, as a support fuel.
    The catalysts used in the combustion are preferably coated with stable metal oxides, in particular an oxide having a cation of Al, Ce, Zr, L or Ba, to which noble metals such as Pd, Pt, Rh or mixed oxides of these parent metals are attached.
    These metal catalysts are non-toxic and do not produce toxic compounds in reactions as in conventional SCR catalysts.
    The temperature in the catalyst is at least 600 ° C, especially 850-1000 ° C under reducing conditions or under both reducing and oxidizing conditions.
    Most preferably, in a three-way catalyst, the exchange is maintained at 50,000-150,000 1 / h, for example about 60,000-100,000 1 / h, and the reductions in the reduction and oxidation catalyst are, for example, about 60,000-200,000 1 / h, preferably 70,000-150,000 1 / h.
    The present technology is particularly suitable for use in situations where the fuel is burned or has been burned in a combustion plant, which is an oil or gas boiler, a gas turbine, a diesel power plant or a similar energy plant.
    As stated above, in one application, the present technology can be applied to generate thermal energy from a hydrocarbonaceous fuel by combustion in at least two stages. In such a solution, in the first combustion stage, the first part of the fuel is burned in the combustion plant to produce heat and nitrogen and oxygen oxide-containing exhaust gas. The heat and exhaust gas from the first combustion stage are then recovered. The second part of the fuel is fed in the second combustion stage to the exhaust gas from the first combustion stage. Air is still supplied to form the combustible gas mixture. The gas mixture thus obtained is catalytically combusted by heat
    20185222 prh 09 -03-2018 to produce and decompose nitrogen and oxygen oxides. As described above, reducing conditions are maintained in at least one catalyst zone and combustion is performed under these conditions at a temperature above 600 ° C.
    The heat from the second combustion stage is recovered.
    In one application, the second combustion stage burns at least 10%, preferably 15-80 mol%, of the total amount of hydrocarbonaceous fuel. With the help of the solution, a significant part can be produced in the second combustion stage, which adds about 60% of the thermal energy to the primary10 energy source.
    In one application, the flue gas of a thermal boiler, turbine or diesel power plant is used as a cooling and heat transfer medium in catalytic combustion. Without a cooling inert excipient in stoichiometric catalytic combustion, the temperature rises above 2500 ° C according to the modeling. This is because catalytic combustion is about twenty times faster than thermal. In the above applications, where the temperature is raised to at least 600 ° C but preferably not more than 1000 ° C, the flue gases of the thermal power plant are preferably used in the catalytic combustion to keep the temperature of the catalytic combustion of the heat storage and transfer medium inert within a preselected temperature range. It has been found that the non-combustible gases contained in the inlet gases, such as nitrogen and carbon dioxide, do not react under the conditions shown but, as inert components, balance the heat and prevent an uncontrolled rise in temperature.
    In the above applications, the thermal energy contained in the combustion gases is recovered. The recovery can be performed in at least one heat transfer step, in which case the thermal energy is preferably transferred to water, air or another liquid or gaseous medium.
    In another embodiment, the present technology is applied to the catalytic purification of exhaust gases containing hydrocarbons and carbon monoxide, hydrocarbons, and soot particles from power plants using hydrocarbon-containing fuel 30 under reducing and oxidizing conditions. In this solution, fuel and air are fed to the exhaust gases to form a gas mixture and the gas mixture is subjected to a single or double process at a temperature above 600 ° C.
    20185222 prh 09 -03- 2018 for secondary catalytic combustion to reduce nitrogen oxides and oxidize wedding, hydrocarbons and soot particles.
    In doing so, the NOx emissions from the catalytic combustion gas shall be 1 ppm or less and the CO and VOC emissions shall not exceed 2 ppm. Small soot particles also burn at the preferred operating temperature of the exhaust burner at 850-1000 ° C, as the soot ignites at about 600 ° C and burns at an accelerating rate above it.
    An exhaust gas burner using the same fuel as a thermal boiler has several advantages over selective (SCR) or non-selective (SNCR) NOx reduction plants:
    - It is a more efficient eliminator of NOx, CO and VOC emissions. It can achieve levels of approx. 1 ppm for NOx emissions and a level of 2 ppm for CO and VOC emissions, depending on the catalyst solution.
    - It can burn small soot particles.
    - It can increase the thermal energy production of the boiler by about 60%.
    - It does not require a separate supplemental fuel or a separate storage and dosing system.
    - Its precious metal catalysts have a longer life than SCR catalysts, in which the catalyst used (V2O5) has a lower thermal and chemical resistance than precious metals. The new replacement SCR catalysts are various zeolites, which in turn are sensitive to sulfur poisoning.
    - SCR catalysts are 5-10 times larger than precious metal catalysts. There is no significant difference in their prices, as the size difference compensates for the difference in unit prices. Precious metal catalysts cost about 60 - 70 € / dm3 and SCR catalysts about 10 € / dm 3 .
    - EPÄ has demonstrated the SCR catalyst as the removal cost of NOx n.
    1400-2000 USD / tNOx. The cost of a catalytic flue gas burner is substantially lower. The facility is smaller and simpler. The reducing agents used in SCR plants, ammonia (NH3) or urea, are about the same price as fuels, but do not produce usable thermal energy.
    20185222 prh 09 -03- 2018
    - The biggest difference arises when the exhaust burner can produce additional energy at a competitive cost. In this case, the elimination of NOx, CO and VOC emissions would take place as a by-product without separate cleaning costs.
    - Ammonia is transported and stored as a 27% aqueous solution because it is very toxic.
    - SCR reduction results in 2-5 ppm ammonia leakage (EPÄ) which must be catalytically oxidised.
    In the following, applications of the present technology will be considered on the basis of the accompanying drawings.
    Figures 1 and 2 show two embodiments, where Figure 1 illustrates a solution in which both thermal and electrical energy is produced from fuel in an energy plant (power plant), whereby the exhaust gas of the energy plant 15 is primarily cleaned by a catalytic combustion process. Figure 2, in turn, shows a solution in which heat is produced in a thermal power plant on the one hand and in a catalytic combustion process on the other.
    As can be seen from the drawings, reference numerals 10; 20; 30 and 50 denote a thermal combustion boiler, diesel power plant, gas turbine 20 or similar energy plant or power plant using gaseous or liquid fuel. In the case of Figure 1, the fuel is fed mainly to an energy plant in which thermal energy is produced, in addition to which part of the thermal energy thus produced produces electricity.
    In the case of both figures, from the exhaust gas exhaust duct of the power plant, the gas 25 is directed to the mixing chamber 12; 22, into which additional air is blown and fuel is injected. The mixing chambers may comprise a distribution network.
    In one application, a mixing cell structure is used. An example of such is the solutions described, for example, in utility models 10627 or CN205001032. Thus, the distribution network may consist of obliquely corrugated steel foils stacked or vii30 laid on top of each other, the waves crosswise. The foils can be attached to each other at intersections, for example by resistance welding or soldering. The flow channels formed by each layer of the cell intersect with each other, causing mixing and turbulence in the flow at higher flow rates.
    20185222 prh 09 -03- 2018
    In a direct channel cell, the flow is laminar. Then the dimensionless Sherwood (Sh) figure describing the mass transfer is about 3 with a flow velocity of 10 m / s. In a mixing cell with a metal body, it is about 10-12.
    From the mixing chamber, the gas passes through a static mixer 13; 23 to catalyst 14; 24,
    25. Behind the catalyst (in the flow direction of the gas mixture) is a non-shown linear lambda sensor arranged to measure and contribute to the control of the air / fuel ratio and a temperature sensor to control the temperature.
    One or two catalysts 14; 24, 25, the gas passes, for example, to one or more heat exchangers 15 made of welded rib tubes; 27, in which heat is transferred to water or other utilization. Heat exchangers 15; 27, may be, for example, made of welded tubes, such as the previously ribbed tubes.
    Figures 3 and 4 show in more detail the structure of their catalytic combustion systems.
    In the figure, reference numerals 30 and 50 denote the production of primary energy by, for example, a diesel engine, a gas turbine or a boiler, from which 20 fuel supply channels 31 are fed to the exhaust gas obtained; 51 along. Air is supplied to form a gas mixture by fans 37; 57. The mixture is stirred prior to the catalyst zone by passing it through a static mixer 38; 58 through. Preferably, the mixture is rich prior to introduction into the catalyst zone.
    In the case of Figure 3, the catalyst zone comprises a cross-flow catalyst 33. In the case of Figure 4, the catalyst zone comprises a recuperative heat exchanger catalyst.
    The first, typically reducing catalyst zone 33; The resulting gas mixture 53 is passed to a second catalyst zone 35; 55, which typically comprises an oxidation catalyst. Additional air is then supplied to the gas mixture by a secondary air supply fan 39; 59.
    20185222 prh 09 -03- 2018
    Prior to start-up, the catalyst or catalysts are typically preheated, e.g., with a hot air blower, gas burner, or similar heater, above the reaction temperature of the catalyst.
    The first catalyst in the exhaust burner may be a conventional straight-pass catalyst when the temperature difference between the exhaust gas and the ignition temperature of the fuel is small (<150 ° C) if the concentrations of carbon monoxide (CO) and nitrogen dioxide (NCEj) in the exhaust gas are high. In C and the other oxygen in the nitrogen dioxide is easily released and reacts aggressively.
    A cross-flow or rotary cell recuperative heat exchanger catalyst 53 is required when the temperature of the incoming gas is substantially lower (> 150 ° C) than the Ignition Temperature of the fuel used in the catalyst.
    In the device according to the invention, the change of the three-way catalyst is 50,000-150,000 1 / h, preferably 60,000-100,000 1 / h, depending on the fuel. In reduction and oxidation catalysts, the exchange is 70,000-200,000 1 / h, preferably 60,000-150,000 1 / h.
    The thermal energy of the hot gas from the second catalyst zone is recovered in the heat exchanger 36; 56, where it is transferred to water, for example. Heat exchangers 36; 56, may be, for example, made of welded tubes, such as the previously ribbed tubes.
    After the heat exchanger, there may be a suction fan 40; 60, unless the powers of the primary power plant and auxiliary air fans are sufficient to carry sufficient gas through the equipment. Exhaust gas, i.e. purified exhaust gas, is led from the apparatus 25 to the exhaust pipe, e.g. 41; 61.
    20185222 prh 09 -03- 2018
    Example
    Generating additional energy
    - Natural gas boiler with a capacity of 60 MW
    - Exhaust gas supply 61,000 Nm 3 / h
    - Additional air supply 35,000 Nm 3 / h
    - Increase natural gas supply to 24 g / Nm 3 at 96,000 Nm 3
    - Additional energy generated by combustion 35.2 MW or 59% (calorific value 55 MJ / k)
    - Temperature after combustion 920 ° C when the inlet temperature is 150 ° C
    - Reduction of NOx
    - NOx emission 500 mg / Nm 3
    - Total NOx 61,000 Nm 3 / hx 500 mg / Nm 3 = 30.5 kg / h
    Comparison with SCR facility
    SCR plant reduction costs according to the lowest cost in the EPA calculation = 1400 USD / ton x 30.5 kg / h x 0.98 = 41.8 USD / h
    Annual cost with SCR technology = 8000 h / a x 41.8 USD / h = 344,400 USD / a
    If the energy produced by the catalytic afterburner is not more expensive than the energy production of the control, then the removal of NOx from the thermal boiler costs nothing, ie the annual savings would be USD 344,400. At the same time, NOx emissions can be reduced to 1 ppm and CO and VOC25 emissions can be reduced to less than 2 ppm with two-stage combustion (Figure 4).
    In order to achieve the objects, the invention is characterized by the features set out in the independent claims.
    20185222 prh 09 -03- 2018
    Reference numbers:10 Primary energy yield11 Generator 5 12 Sharing Networks13 Static mixer14 3 -catalyst escort15 Heat exchanger20 Primary energy yield. 10 22 Sharing Networks23 Static mixer24 Just sty skataly escort25 Without a network26 Oxidation catalyst 15 27 Heat exchanger30 Primary energy yield31 Fuel supply ducts32 Rich connection33 Cross-flow catalytic converter 20 34 Skinny mixture35 Oxidation catalyst36 Heat exchanger37 Fan38 Static mixer 25 39 The secondary air supply fan40 Vacuum fan (if required)41 Exhaust pipe (exhaust pipe)50 Primary energy yield.51 Fuel supply ducts 30 52 Rich connection53 Recuperative heat exchanger catalyst54 Skinny mixture55 Oxidation catalyst56 Heat exchanger 35 57 Fan58 Static mixer59 The secondary air supply fan60 Vacuum fan (if required)61 Exhaust pipe (exhaust pipe)
    权利要求:
    Claims (20)
    [1]
    The claims
    A method for producing thermal energy from a hydrocarbonaceous fuel, the method comprising
    - the fuel is burned at an incineration plant at an elevated temperature,
    - the heat from combustion is recovered and
    - combustion exhaust gases and soot particles are cleaned by catalytic exhaust combustion,
    10 characterized in that
    fuel and air are supplied to the exhaust gases to form a gas mixture, and
    - the gas mixture is subjected to a catalytic combustion at a temperature of at least 600 ° C, preferably above 600 ° C, in order to reduce nitrogen oxides and to heat,
    15 for the oxidation of hydrocarbons and soot particles.
    [2]
    Process according to Claim 1, characterized in that the catalytic combustion is carried out under reducing and oxidizing conditions, respectively, in one or more stages.
    [3]
    Method according to claims 1 and 2, characterized in that the exhaust gases, the fuel and the air are mixed in nested perforated supply pipes and in a static mixer to form a uniformly mixed gas mixture.
    25
    [4]
    Process according to one of the preceding claims, characterized in that the gas mixture is subjected to catalytic combustion in a three-way catalyst to an oxidation and reduction catalyst.
    [5]
    Process according to one of the preceding claims, characterized in that the kaa30 mixture is combusted in a three-way catalyst with a stoichiometric oxygen / auxiliary fuel ratio in an incinerator for the oxidation of unburned CO and VOCs and for the reduction of NOx emissions and the oxidation of soot particles.
    20185222 prh 09 -03- 2018
    [6]
    Process according to one of Claims 1 to 4, characterized in that the gas mixture is first burned in an oxidation and reduction catalyst with a rich auxiliary fuel / oxygen mixture for the reduction of nitrogen oxides and a lean auxiliary fuel / oxygen mixture for the oxidation of CO and VOCs and soot particles.
    [7]
    Process according to one of the preceding claims, characterized in that the temperature in the catalyst is from 850 to 1000 ° C under at least reducing conditions or under both reducing and oxidizing conditions.
    [8]
    Process according to one of the preceding claims, characterized in that the change of the three-way catalyst is from 50,000 to 150,000 1 / h, preferably from 60,000 to 100,000 1 / h, and the changes of the reduction and oxidation catalyst are from 60,000 to 200,000 1 / h, preferably from 70,000 to 150,000 1 / h .
    Method according to one of the preceding claims, characterized in that the fuel is burned in a combustion plant which is an oil or gas boiler, a gas turbine, a diesel power plant or a similar energy plant.
    Method according to one of the preceding claims, characterized in that
    Additional air and fuel are supplied to the 20 exhaust gas burners and their supply is controlled by post-catalyst temperature and linear oxygen sensors according to the need for the air / fuel ratio required by each catalyst.
    [9]
    A method for producing thermal energy from a hydrocarbonaceous fuel by combustion in at least two stages according to any one of the preceding claims, characterized in that
    - in the first combustion stage, the first part of the fuel is burned in the combustion plant to produce heat and exhaust gases containing nitrogen and oxygen oxides,
    - the heat from the first combustion stage is recovered separately,
    In the second combustion stage, a second part of the fuel and air are fed to the exhaust gas from the previous combustion stage to form a gas mixture,
    - the gas mixture thus obtained is catalytically combusted to produce heat and to decompose nitrogen and oxygen oxides,
    20185222 prh 09 -03-20118 wherein reducing conditions are maintained in at least one catalyst zone and combustion is performed under these conditions at a temperature above 600 ° C, after which the heat from the second combustion stage is recovered.
    5
    [10]
    Process according to Claim 11, characterized in that at least 10%, preferably 15 to 80 mol%, of the total amount of hydrocarbon-containing fuel is burned in the second combustion stage.
    [11]
    A method according to claim 11 or 12, characterized in that in the second combustion stage 10 up to about 60% more thermal energy is produced for the primary energy source.
    [12]
    Method according to one of the preceding claims, characterized in that the flue gases of the thermal power plant are used inert to maintain the temperature of the catalytic combustion of the heat storage and transfer medium in a preselected temperature range.
    [13]
    Process according to one of the preceding claims, characterized in that the catalysts used in the combustion are coated with stable metal oxides, in particular an oxide having a cation of Al, Ce, Zr, L or Ba, and to which precious metals such as Pd, Pt, Rh or these parent metals are attached. mixed oxide.
    [14]
    Process according to one of the preceding claims, characterized in that the noble metal catalysts are non-toxic and the reactions do not give rise to toxic compounds as in conventional SCR catalysts.
    25
    [15]
    Method according to one of the preceding claims, characterized in that the thermal energy contained in the combustion gases is recovered in at least one heat transfer step, the thermal energy being transferred to water, air or another liquid or gaseous medium.
    30
    [16]
    18. Process for the catalytic cleaning of exhaust gases containing carbon monoxide, hydrocarbons and soot particles from hydrocarbon-fired power plants under reducing and oxidising conditions, characterized in that:
    - fuel and air are fed into the exhaust gases to form a gas mixture
    20185222 prh 09 -03- 2018 sex and
    - the gas mixture is subjected to a single or two-stage catalytic combustion at a temperature of more than 600 ° C for the reduction of nitrogen oxides and the oxidation of fumes, hydrocarbons and soot particles.
    [17]
    Process according to Claim 18, characterized in that the NOx emission level of the gas from the catalytic combustion is 1 ppm or less and the level of CO and VOC emissions is at most 2 ppm.
    Process according to one of Claims 18 or 19, characterized in that the catalytic combustion is carried out in a catalyst in which the temperature is maintained at 850 to 1000 ° C.
    Method according to one of Claims 18 to 20, characterized in that
    The 15 gas mixture is combusted in a three-way catalyst with a stoichiometric oxygen / auxiliary fuel ratio in an incinerator to oxidize unburned CO and VOCs and to reduce NOx emissions and to oxidize soot particles.
    Method according to one of Claims 18 to 21, characterized in that
    [18]
    The gas mixture is first combusted in an oxidation and reduction catalyst with a rich supplemental fuel / oxygen mixture to reduce nitrogen oxides and a lean supplemental fuel / oxygen mixture to oxidize CO and VOCs and soot particles.
    [19]
    Method according to Claim 21 or 22, characterized in that
    [20]
    The three-way catalyst exchange is 50,000-150,000 1 / h preferably 60,000-100,000 1 / h and the reduction and oxidation catalyst exchanges are 60,000-200,000 1 / h preferably 70,000-150,000 1 / h.
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    同族专利:
    公开号 | 公开日
    US20200392884A1|2020-12-17|
    CN111836997A|2020-10-27|
    FI128631B|2020-09-15|
    WO2019170965A1|2019-09-12|
    KR20200130261A|2020-11-18|
    EP3762651A1|2021-01-13|
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    US4118171A|1976-12-22|1978-10-03|Engelhard Minerals & Chemicals Corporation|Method for effecting sustained combustion of carbonaceous fuel|
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    US10544720B2|2016-02-05|2020-01-28|Cummins Inc.|System and method for managing contaminant storage in a storage catalyst|CN112264007B|2020-11-13|2021-07-20|中南大学|Aromatic compound catalytic combustion catalyst and preparation and application thereof|
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