TW201441146A - Combustor for sulfur containing material - Google Patents

Abstract

The present disclosure relates to a combustor comprising one or more inlets and one outlet both in fluid connection with a combustion chamber, one or more of said inlets configured for receiving a fuel, an oxidant, a particle precursor and optionally a further compound, at least one of which contains a compound comprising sulfur in an oxidation state equal to or below 0, and said combustor configured for combustion of the fuel and the compound comprising sulfur in the presence of the particle precursor in the combustion chamber, providing a stream of hot process gas comprising sulfur dioxide and particles having a diameter between 2 and 500 nm, preferably between 10 and 100 nm with the associated benefit of said particles supporting condensation of sulfuric acid vapor in a downstream condenser.

Description

Sulphur-containing burner

The present invention relates to a burner that receives a fuel and particle precursor containing a sulfur-containing compound and provides a process gas comprising sulfur dioxide and a condensed core, and a method of producing sulfuric acid using the burner.

The effect of adding a condensed nucleus to a process gas containing sulfuric acid vapor is described in the patent US Pat. No. 5,198,206, "Condensing sulfuric acid vapors to producer sulfuric acid". In this patent, different ways of creating a condensed core in an external unit are described, for example by decomposing polyoxyxide oil, by operating a hydrocarbon flame under expected soot formation or by adding welding fumes.

In the patent US 7,361,326 "Process for the production of sulfuric acid", a sulfuric acid process is described and the optimum number of condensed nuclei in the process gas is analyzed.

According to the prior art, a process stream having a high concentration of core is added to a process gas by adding a side stream having a high concentration of sulfur to a process gas volume having sulfuric acid vapor located not upstream of the sulfuric acid condenser or to a process gas containing sulfur dioxide upstream of the sulfur dioxide converter. Add a condensed core. This means that solid particles must be produced in the external unit and the two streams need to be well mixed to achieve the best acid mist control in the sulphuric acid condenser, but the prerequisite for choosing a solution involving the generation of particles in the side stream may be to generate the particles. Interference with the main desulfurization process is minimized.

However, such sidestreams require the introduction of an additional volume of gas into the sulfuric acid condenser, thereby increasing the size required for the sulfuric acid condenser. In addition, the external particle generating unit needs to individually feed the fuel gas containing no sulfur compound and needs to maintain the burner management and rotation to some extent. device.

The present invention overcomes these deficiencies, and according to the present invention, the formation of a solid condensed core directly in the main burner thus naturally ensures perfect mixing of the particles with the process gas.

Furthermore, the thermal decomposition temperature of the polyoxygenated oil is achieved by the combustion of the feed gas with a high concentration of reduced sulfur compounds which must be combusted for the production of sulfuric acid. Therefore, a "pure" hydrocarbon fuel for the external particle generating unit as described in US 5,198,206 is not required.

Hereinafter, the unit Nm ³ should be understood as "standard" m ³ , that is, the amount of gas occupying this volume at 0 ° C and 1 atm.

The term fog control potential is understood herein to mean the sulfuric acid vapor condensation potential of a given set of conditions and the size of the condensing core.

Unless specifically stated otherwise, the term particle or condensed core shall be considered equivalent.

The term particle precursor is understood to mean a compound which, under specified conditions, can react to form particles having a size suitable for use as a condensed core.

Hereinafter, when referring to a fuel containing a sulfur-containing compound, this is understood to mean a combustible sulfur compound in a reduced form or a mixture comprising a sulfur compound and a fuel, both of which can be reacted to form a hot process gas comprising sulfur dioxide.

Hereinafter, when the term oxidation state is understood in accordance with the IUPAC definition and particularly with respect to sulfur, this would mean that the oxidation state of sulfur in CS ₂ , COS and H ₂ S is -2 and is 0 in elemental sulfur, and thus The compound is an example of a compound containing sulfur having an oxidation state equal to or lower than 0, and sulfur has an oxidation state of +4 in SO ₂ and an oxidation state of +6 in SO ₃ .

In general, unless otherwise specified, a chemical reaction may be described by any of the terms conversion, decomposition, reaction, or oxidation, and no particular understanding is to be taken therefrom.

The present invention relates to a combustor comprising one or more inlets and an outlet each connected to a combustion chamber, one or more of which are configured to receive fuel, oxygen a chemical, a particle precursor, and optionally another compound, at least one of which contains a sulfur-containing compound having a sulfur oxidation state equal to or lower than 0, and the burner is configured for presence in a particle precursor in a combustion chamber Burning a fuel and a sulfur-containing compound to provide a hot process gas stream comprising sulfur dioxide and particles having a diameter between 2 and 500 nm, preferably between 10 and 100 nm, with the associated benefit that the particles support sulfuric acid vapor downstream Condensation in the condenser.

In another embodiment, the combustor is configured to combine the particle precursor with the oxidant for at least 0.1 s (such as 0.5 s) upstream of the combustion zone prior to combustion (ie, by oxidation), with associated benefits. The combined oxidant and particle precursor are a mixture of gases that are easy to handle and will mix well as they enter the combustion zone.

In another embodiment, the combustor is configured to combine the particle precursor with the fuel and/or other compounds as the case may be, prior to combustion, at least 0.1 s or 0.5 s upstream of the combustion zone, with the associated benefit being self-contained The combination of the particle precursor and the fuel separates the pure oxidant gas while obtaining a well mixed gas mixture.

In another embodiment, the combustor is configured such that one of the inlets receives a combination of any two, three or four of a fuel, an oxidant, a particle precursor, and optionally another compound, A related benefit is the optimal logistics mix and control based on the available processes.

In another embodiment including a downstream inlet fluidly coupled to the combustion chamber, the downstream inlet is configured to direct the particle precursor, optionally combined with another quantity of fuel and/or oxidant, into the combustion chamber At one location where combustion is at least partially completed, the associated benefit is that the formation of the core by the particle precursor is less dependent on fuel combustion while at the same time benefiting from the high temperatures and mixing of turbulent combustion.

In another embodiment, the particle precursor is selected from the group consisting of a ruthenium-based material (such as a polyoxygenated oil), an organometallic or a group of soot hydrocarbons, with the associated benefit that the particles formed are harmless cerium oxide or other sulphuric acid. Complex low concentration contaminants.

In another embodiment, the process gas comprises 4.10 ¹⁰ to 1.5.10 ¹² particles/Nm ³ (0 ° C, 1 atm), the particles having a distance between 2 and 500 nm, preferably between 10 and 100 nm. The particle size, the associated benefit is that the particles have the highest condensation potential of the sulfuric acid vapor as described in the patent US 7,361,326 and the lowest particle deposition between the processing equipment and the burner outlet and the sulfuric acid condenser inlet catalyst. Good balance.

In another embodiment, at least 50%, 80%, or 90% of the sulfur-containing compound is a compound selected from the group consisting of hydrogen sulfide, carbon disulfide, carbonyl sulfide, and elemental sulfur, with the associated benefit that the sulfur-containing compounds are inexpensive Either or even waste materials make it possible to produce sulfuric acid cost-effectively while providing a desulfurization process gas.

In another embodiment, the temperature during combustion is at least 600 ° C, preferably at least 700 ° C and most preferably at least 1000 ° C, and the residence time is 0.1 s, 0.3 s or 0.5 s to 1.5 s, 2.5 s or 5 s. The related benefit is that the temperature and residence time are very suitable for forming core particles or decomposing particle precursors at 600 ° C or higher, burning hydrogen sulfide at 700 ° C or higher, and burning other sulfur compounds at 1000 ° C or higher.

In another embodiment, the burner includes a particle precursor saturator including a vessel for the liquid particle precursor, the vessel having a controlled temperature for controlling the partial pressure of the particle precursor, and the vessel having a receiver for receiving An inlet for the carrier gas stream and configured to direct a combined flow of the carrier gas and the particle precursor to the outlet of the combustor, and optionally a combined particle precursor stream for diluting the carrier gas and the particle precursor The associated benefit of the component is that the particle precursor flow is completely defined by the flow rate of the carrier gas stream and the temperature of the liquid particle precursor, and dilution has the additional benefit of having a dew point temperature reduction of the diluted stream to avoid particle precursor condensation.

In another embodiment, the carrier gas is nitrogen or air, with the associated benefit that the carrier gases are readily available, inexpensive, and not complicated to handle.

Another aspect of the invention is directed to a method of producing sulfuric acid comprising the steps of: a. providing a reactant comprising a fuel, a particle precursor, an oxidant, and a sulfur compound, such as sulfur in a combustible form, which will constitute at least a portion of the fuel in the form of a flammable form of sulfur, b. causing the particle The precursor, the oxidant, and the fuel react in the combustion zone, wherein the reaction occurs within a residence time of 5 s, 2.5 s, or 1.5 s to form a combustion zone effluent, c. the process effluent from the combustion zone forms a process gas, d. The process gas is contacted with a material having catalytic activity for oxidizing sulfur dioxide to sulfur trioxide, e. reacting sulfur trioxide with water to form sulfuric acid vapor, f. condensing sulfuric acid vapor in the condenser, and g. from the condenser Extracting sulfuric acid and desulfurization process gas, and the method further comprises one or both of the following steps (h) and (i), which respectively produce a process gas comprising sulfur dioxide and particles in the step (c); The compound is sulfur dioxide, which directs at least a portion of the sulfur dioxide to bypass the combustion zone and combine with the effluent of the combustion zone to form the process gas. A related benefit is that sulfuric acid condenses due to the presence of a condensed core. Effective and simple.

In the case where sulfur is not in the form of sulfur dioxide, this aspect corresponds to a method of producing sulfuric acid comprising the steps of: a. providing a reactant comprising a fuel, a particle precursor, an oxidant, and optionally another compound, at least one of which a sulfur-containing compound having a sulfur oxidation state of less than or equal to 0, b. directing the sulfur compound to a combustion zone for combustion, c. reacting the particle precursor, the oxidant, and the fuel in a combustion zone, in the combustion zone The reaction takes place in a residence time of 5 s, 2.5 s or even 1.5 s to form a effluent from the combustion zone, d. a process gas is formed from the effluent from the combustion zone, e. the process gas is directed to catalyze the oxidation of sulphur dioxide to sulphur trioxide. Active Contact with material, f. reacting sulfur trioxide with water to form sulfuric acid vapor, g. condensing sulfuric acid vapor in the condenser, and h. extracting sulfuric acid and desulfurization process gas from the condenser, the related benefit being due to the presence of a condensation core This makes the condensation of sulfuric acid effective and simple.

In another embodiment, the method includes the step of adding water vapor at a location upstream of the condenser, the associated benefit of which is to make sulfuric acid condensation efficient and simple, in the case of conditions involving process gases having substoichiometric amounts of water. in this way.

In another embodiment, the method includes the steps of obtaining a measure of the amount of acid mist and controlling the amount of particle precursor added based on the measured value, the related benefit being that even under varying operating conditions Minimize the amount of acid mist. Controlling the number of particles per volume may involve controlling the flow of the carrier gas to the saturator, temperature, or splitting a certain proportion of the particle precursor gas.

A further aspect of a particular embodiment of the invention relates to an apparatus for producing sulfuric acid comprising a burner as described above, with the associated benefit of making sulfuric acid condensation efficient and simple due to the presence of a condensed core.

More particularly, the present invention describes a burner for producing particles for controlling the combustion of self-reducing sulfur compounds (eg, H ₂ S, CS ₂ , COS, and elemental sulfur) and, where appropriate, auxiliary fuel combustion to produce concentrated sulfuric acid. The acid mist of the processing equipment.

The sulfuric acid vapor condensation and the nucleus required for subsequent growth of the sulfuric acid droplets formed in the sulfuric acid condenser are formed by thermal decomposition or oxidation of a particle precursor such as polyoxyxane vapor in a combustion chamber for oxidizing the reduced sulfur compound. . Alternatively, the particle precursor may also be an organometallic compound or a soot hydrocarbon.

The particle precursor can be added to the combustion air required for the combustion of the reduced sulfur compound by flowing a small amount and a controlled carrier gas such as air or nitrogen through a vessel having, for example, a polyoxygenated oil. The temperature of the polyoxygenated oil is kept constant to ensure a constant vapor pressure.

The carrier gas saturated with the polyoxygenated oil is mixed with another carrier gas stream to lower the dew point temperature to avoid vapor condensation. The polyoxygenated oil vapor is added to the main combustion air stream via a preferred heat traced line, possibly upstream of the combustion chamber to ensure complete mixing of the vapor with the air.

This polyoxygenated oil saturator is virtually maintenance free because there are no flames or moving parts in this unit.

In the combustion chamber, the temperature is much higher than the polyoxysulfide vapor decomposition temperature of about 600 ° C and thus forms very fine (<100 nm) ceria primary particles.

The primary particles will collide and aggregate into larger particles, but because the particle concentration is low, aggregation is minimized, and the aggregated particles will typically have a diameter range of 2 to 500 nm. Another effect of the small particle size is that most of the particles remain in the gas phase even in the presence of a particulate filter as the case may be and continue downstream through the catalyst bed.

The solid condensate core formed in the combustion chamber moves with the gas through the waste heat boiler (if present), the SO ₂ oxidation catalyst bed and the heat exchanger, and then into the sulfuric acid condenser where it will assist in the condensation of the sulfuric acid vapor to The acid mist emission of the sulfuric acid condenser is reduced.

The size of the condensing core should be in the range of 2 to 500 nm, where the diffusion coefficient and impact tendency are low enough so as not to be trapped on the surface of the viscous sulfuric acid catalyst.

The acid mist discharge from the sulphuric acid condenser will typically be monitored by an acid mist analyzer, which can be used as an input to the acid mist controller, for example by controlling the carrier gas flow to a temperature controller in a polyoxyxene vessel or a polyoxyxene vessel. To control particle concentration, the goal is to minimize acid mist emissions.

The condensed core terminates in the sulfuric acid product, which means that the smaller the nucleus, the lower the concentration of cerium oxide found in the sulphuric acid.

Figure 1 shows a burner according to an embodiment of the invention, 2 shows a burner according to another embodiment of the present invention, and FIG. 3 shows a process layout and processing apparatus according to other embodiments of the present invention, wherein the sulfur source is flammable.

According to Figure 1, the side stream 10 is separated from a carrier gas stream 18 such as ambient air or nitrogen. The side stream 10 is directed to a vessel 12 containing a liquid particle precursor, such as a polyoxyxide oil 14. This will result in a particle precursor gas stream 16 having a polysulfonium oil concentration near saturation. To ensure that the polyoxysulfide oil does not condense, the gas stream can preferably be transported via a hot line and it can also be diluted by a primary carrier gas stream 18, optionally selected to avoid condensation. The particle precursor gas stream 16, the oxidant (such as ambient air) 20, and the fuel containing the sulfur-containing compound 22, such as the exhaust stream comprising H ₂ S from the coal gasification process, are directed to the combustion chamber 24 of the combustor 26 where It is ignited at a temperature sufficient to burn H ₂ S to form primarily SO ₂ and H ₂ O and SiO _{2 is} formed for the polyoxyxene oil to form process gas 28 comprising sulfur dioxide and particles which condense downstream The process will act as a condensing core.

In other embodiments, the combination of oxidant 20, fuel containing sulfur-containing compound 22, and particle precursor gas stream 16 can be added to the third component by combining any two of the materials or by at the same location (eg, It is produced by combining all three in the combustion chamber. The combination can also be stepwise, for example, to provide optimal mixing. The burner 26 can also be fed with a single fuel/oxidant stream comprising an oxidant and a sulfur-containing compound 22, such as in the case of a CS ₂ and H ₂ S waste stream, which will be obtained from the production of viscose fibers.

In another embodiment illustrated in FIG. 2, particulate precursor gas 16 may be added to the region of combustion zone 24 or downstream of combustion zone 24 where the temperature is sufficient to produce particles, such as in the formation of polyoxosulfonate. In the case of a ruthenium oxide core, it is higher than 600 °C.

Figure 3 illustrates another embodiment of the invention which is a method of producing sulfuric acid using a burner 26 as described above. Such a method would involve directing a fuel containing sulfur-containing compound 22 (as appropriate with an auxiliary fuel combination), oxidant 20, and particle precursor 14 for combination and combustion in the combustor. The sulfur-containing compound 22 contained in the fuel may be H ₂ S. The oxidant 20 may typically be ambient air preheated in the process as indicated, but it may also be pure oxygen, which has the benefit of requiring a smaller process. volume. Alternatively, combustor 26 can receive a fuel/oxidant mixture comprising the sulfur-containing compound and an oxidant. In combustor 26, this mixture will be combusted to form a hot process gas 28 which is cooled in waste heat boiler 30 and directed to a sulfur dioxide converter 32 in which sulfur dioxide is placed in one or several beds of catalytically active material 34. Converted to sulfur trioxide. In order to recover energy and to ensure high conversion by shifting the balance between SO ₂ and SO ₃ towards SO ₃ , the converter may comprise one or more interlayer coolers 36, ie positioned to position the catalytically active material A product gas cooled heat exchanger between 34. Downstream of the reformer 32, SO ₃ the reaction of process gas in the presence of water to form the H ₂ SO ₄ and is formed to a condenser 38 for condensing the H ₂ SO ₄ and concentrated sulfuric acid 40 for providing a desulfurization process is channeled Gas 42 may be directed to stack 44. The acid mist analyzer 50 can be configured to provide input to the controller 52 that controls the particle precursor concentration by controlling the air flowing through the liquid particle precursor.

In another embodiment, the particle precursor can also be added directly to the oxidant or ambient air stream in liquid or solution form. This would require accurate metering of the pump and has the benefit of avoiding the complexity of the saturator unit.

10‧‧‧lateral flow

12‧‧‧ Container

14‧‧‧Particle precursor

16‧‧‧Particle precursor gas flow/particle precursor gas

18‧‧‧Airstream

20‧‧‧Oxidant

22‧‧‧Sulphur compounds

24‧‧‧Combustion/burning area

26‧‧‧ Burner

28‧‧‧Process Gas

Claims (15)

A combustor comprising one or more inlets and an outlet each connected to a combustion chamber, one or more of which are configured to receive a fuel, an oxidant, a particle precursor, and optionally a compound, at least one of which contains a sulfur-containing compound having a sulfur oxidation state equal to or lower than 0, and the burner is configured to combust the fuel and the sulfur-containing compound in the combustion chamber in the presence of the particle precursor, Thereby a hot process gas stream comprising sulfur dioxide and particles having a diameter between 2 and 500 nm, preferably between 10 and 100 nm, is provided. A burner as claimed in claim 1 is configured to combine the particle precursor with the oxidant prior to combustion at least 0.1 s (such as 0.5 s) upstream of the combustion zone. A burner according to claim 1 of the invention, which is configured to combine the particle precursor with the fuel and/or the additional compound present as appropriate, prior to combustion, at least 0.1 s or 0.5 s upstream of the combustion zone. A burner as claimed in claim 1, item 2, or item 3, configured to cause one of the inlets to receive the fuel, the oxidant, the particle precursor, and the additional condition Any combination of two, three or four of the compounds. A burner according to claim 1 or 4, comprising a downstream inlet fluidly connected to the combustion chamber, the downstream inlet being configured to use the particle precursor, optionally with a certain amount of fuel and The oxidant combination is directed to a location in the combustion chamber where combustion is at least partially completed. A burner according to claim 1, 2, 3, 4 or 5, wherein the particle precursor is selected from the group consisting of a ruthenium-based material (such as a polysiloxane), an organometallic or a soot hydrocarbon. Group. A burner according to claim 1, item 2, item 3, item 4, item 5 or item 6 is characterized in that the process gas comprises 4.10 ¹⁰ to 1.5.10 ¹² particles/ Nm ³ (0 ° C, 1 atm), the particles have a particle size of between 2 and 500 nm, preferably between 10 and 100 nm. A burner according to claim 1, item 2, item 3, item 4, item 5, item 6, or item 7, wherein at least 50%, 80% or 90% of the sulfur-containing compound It is a compound selected from the list comprising hydrogen sulfide, carbon disulfide, carbonyl sulfide, and elemental sulfur. For example, in the burner of claim 1, the second item, the third item, the fourth item, the fifth item, the sixth item, the seventh item or the seventh item, wherein the temperature during the combustion period is at least 600 ° C, Preferably, it is at least 700 ° C and most preferably at least 1000 ° C, and the residence time is 0.1 s, 0.3 s or 0.5 s to 1.5 s, 2.5 s or 5 s. A burner according to claim 1, item 2, item 3, item 4, item 5, item 6, item 7, item 8, or item 9 additionally includes particle precursor saturation And a container for a liquid particle precursor having a controlled temperature for controlling a partial pressure of the particle precursor, the container having an inlet for receiving a carrier gas stream and configured to carry a carrier gas In combination with the particle precursor, the particle precursor stream is directed to the exit of the combustor and, as the case may be, further comprises means for diluting the combined stream of carrier gas and particle precursor. A burner according to claim 10, wherein the carrier gas is nitrogen or air. A method of producing sulfuric acid comprising the steps of: a. providing a reactant comprising a fuel, a particle precursor, an oxidizing agent, and optionally another compound, at least one of which contains a sulfur-containing compound having a sulfur oxidation state of less than or equal to zero, b. directing the sulfur compound to the combustion zone for combustion, c. reacting the particle precursor, the oxidant, and the fuel in a combustion zone, wherein the reaction occurs within a residence time of 5 s, preferably 2.5 s, forming a combustion zone An effluent, d. forming a process gas from the effluent of the combustion zone, e. directing the process gas to have a catalytic activity of oxidizing sulfur dioxide to sulfur trioxide Contact with the material, f. reacting sulfur trioxide with water to form sulfuric acid vapor, g. condensing sulfuric acid vapor in the condenser, and h. extracting sulfuric acid and desulfurization process gas from the condenser. The method of claim 11 or 12, further comprising the step of adding water vapor upstream of the condenser. The method of claim 11, wherein the method further comprises the step of obtaining a measurement of the amount of acid mist and controlling the amount of the particle precursor to be added based on the measurement. An apparatus for producing sulfuric acid, comprising a burner according to any one of the preceding claims.