Converting solid waste into syngas and hydrogen

Abstract

A method and apparatus (1) for converting solid recovered fuel particles (117) made from municipal solid waste (103) allows the municipal solid waste (103) to be converted into high yields of hydrogen, rather than landfilling or incinerating the municipal solid waste (103). The hydrogen-rich product gas stream (601) can be used as a feedstock for chemical reactions or for storing energy in a releasable manner.

Description

[0001] The subject of the present invention is the conversion of solid waste, such as municipal solid waste and / or biomass in the form of solid recovered fuel (SRF) particles, into a hydrogen-rich product stream, preferably into pure hydrogen.

[0002] Municipal solid waste (MSW) is generated all over the world and must be treated. MSW is either landfilled or incinerated. Incineration focuses on maximizing the energy content of MSW rather than recovering or reusing the contents of MSW at a molecular scale as in chemical recycling. Incineration creates issues regarding the emission of pollutants into the atmosphere. In addition, the products generated through incineration, such as fly ash, bottom ash, gypsum and activated coal containing heavy metals and / or dioxins, pose further challenges for their further use and / or processing. In addition, the efficiency of waste-to-power, i.e. the amount of calorific value converted to thermal energy, is low, typically only in the range of 20% to 25%.

[0003] Based on this, the object of the present invention is to overcome the disadvantages known from the prior art.

[0004] This object is solved by the features of the independent claims. The dependent claims relate to further embodiments of the invention. Further embodiments can be derived from the description including the drawings and the corresponding description of the drawings.

[0005] The method of processing solid recovered fuel particles of the present invention comprises the following steps:

[0006] a) calcining the particles at a calcination temperature of 250° C. to 300° C. to produce charred particles and calcination gases, wherein step a) is preferably carried out in a calcination unit as described below;

[0007] b) grinding the charred particles in a first grinding step into coarsely ground charred particles, step b) preferably being carried out in a second mill as described below;

[0008] c) removing metal residues from the coarsely ground charred particles, step c) is preferably performed using a third metal removal unit as described below;

[0009] d) grinding the coarsely ground charred particles into finely ground charred particles, step d) is preferably carried out in a third mill as described below;

[0010] e) gasifying the finely ground charred particles into a raw synthesis gas in an entrained flow gasification process, step e) is preferably carried out in a gasification unit as described below;

[0011] f) performing a CO shift reaction on the crude synthesis gas to produce a shifted synthesis gas, wherein step f) is preferably performed in a CO shift unit as described below;

[0012] g) removing carbon dioxide and hydrogen sulfide from the shifted synthesis gas to produce synthesis gas; and

[0013] h) producing a hydrogen-rich product gas stream by purifying the synthesis gas, steps g) and h) preferably being carried out in a gas cleaning unit as described below.

[0014] According to the invention, steps a) to h) are carried out in the order described above, i.e. first step a), then step b), then step c), then step d), and so on. The term roasting in step a) is understood as a thermochemical treatment of the solid recycled fuel particles at a temperature of 250° C. to 320° C. It is carried out at atmospheric pressure and without the addition of additional oxygen, e.g. without the supply of air. During the roasting process, the water contained in the solid recycled fuel particles evaporates, as do the volatiles contained in the solid recycled fuel particles. The biopolymers contained in the solid recycled fuel particles partially decompose under the release of the volatiles. The products of the roasting process are charred particles and roasting gases.

[0015] The term hydrogen-rich gas stream or hydrogen-enriched gas stream is understood to mean a gas comprising at least 90% by volume of hydrogen, preferably at least 95% by volume of hydrogen, in particular at least 99.5% by volume of hydrogen. The remainder comprises argon (Ar), nitrogen (N2), carbon monoxide (CO) and carbon dioxide (CO2). Preferably, in steps g) and h), carbon dioxide and hydrogen sulfide are first removed by adsorption, after which hydrogen is separated from the remainder secondly by a pressure swing adsorption (PSA) process to form a hydrogen-rich product gas stream, wherein the hydrogen content is preferably at least 99.5% by volume.

[0016] Preferably, the solid recovered fuel pellets are produced from municipal solid waste, possibly with the addition of biomass, preferably as disclosed below in connection with the pelletizing plant, in particular with reference to Figure 1 and Figure 3 In the process described, most of the metal residues are removed from the waste before producing solid recovered fuel particles. However, this may not completely remove the metal residues. Therefore, after step b), the amount of metal residues in the charred particles is further reduced in step c). Due to the application of eddy current technology, both ferrous and non-ferrous metal residues can be removed from the coarsely ground charred particles.

[0017] In step b), a grinding process is performed to produce a first particle distribution having a first maximum particle size of preferably less than 10 mm [millimeters]. In step d), a grinding process is performed to produce a second particle distribution having a second maximum particle size significantly smaller than the first maximum particle size. Preferably, the second maximum particle size is 350 μm [micrometers]. The second maximum particle size is preferably selected to allow efficient entrained flow gasification in step e). This allows efficient removal of metal residues in step c) and efficient entrained flow gasification in step e).

[0018] The entrained-flow gasification in step e) is preferably carried out using an all-water quench of the synthesis gas produced during the entrained-flow gasification. The quench causes any solids included in the synthesis gas to solidify, even in a molten state, and to be collected as slag in the process. The quench water is recycled, i.e. preferably no water is discharged from the system. The waste water of the process is treated and evaporated, ultimately producing sodium chloride (NaCl) as a by-product. The condensate is reused in the process as process feed water.

[0019] The process of the invention allows the chemical recovery of municipal solid waste producing hydrogen which can be used as a feedstock in chemical processes and / or for energy storage.

[0020] According to an embodiment, the torrefaction gas produced in step a) is thermally cracked to produce a torrefaction synthesis gas which is mixed with the raw synthesis gas produced in step e) before step f).

[0021] The thermal cracking of the torrefaction gas is carried out in a torrefaction gas processing unit, which will be described in detail below, in particular with reference to Figure 4 The thermal cracking is preferably carried out using a substoichiometric oxidation process to crack long hydrocarbons that may be present in the torrefaction gas and / or the fuel gas used for the thermal cracking. Preferably, an oxygen-enriched gas stream with 95% by volume of oxygen, preferably pure oxygen, is used in the thermal cracking process. Following the thermal cracking of the torrefaction gas, the torrefaction synthesis gas can also be used for chemical recovery instead of burning it.

[0022] According to an embodiment in step b), the charred particles are ground to a particle size of less than 10 mm. This allows efficient removal of metal residues in step c). Step b) is preferably carried out in a second mill as described below.

[0023] According to an embodiment in step c), eddy current technology is used to remove the metal residues. The eddy current is applied in such a way that both ferrous and non-ferrous metal residues are removed. Step c) is preferably performed using a third metal removal unit as described below.

[0024] According to an embodiment in step d), the coarsely ground char particles are ground to a particle size of less than 500 μm [micrometers]. This allows for efficient entrained-flow gasification of the finely ground char particles. Ground biomass may be added to the finely ground char particles before entrained-flow gasification as described below. Step d) is preferably carried out in a third mill as described below.

[0025] According to an embodiment in step g), carbon dioxide (CO2) and hydrogen sulfide (H2S) are removed from the synthesis gas by adsorption. The corresponding carbon dioxide is purged from the corresponding at least one adsorber and used as a feedstock for a chemical process or purged into the environment. The hydrogen sulfide is converted into elemental sulfur using the Claus process. The corresponding Claus unit offgas is hydrotreated and recycled to the corresponding adsorber.

[0026] According to an embodiment in step g), hydrogen is separated from the synthesis gas using pressure swing adsorption (PSA) to produce a hydrogen-rich product gas stream and a purge gas.

[0027] According to an embodiment, at least a part of the purge gas is provided to the CO shift reaction in step e). This allows to increase the conversion efficiency in the CO shift unit and to increase the overall hydrogen production.

[0028] According to an embodiment, a portion of the purge gas is used as fuel gas.

[0029] The purge gas includes at least one of carbon monoxide (CO), carbon dioxide (CO 2 ), nitrogen (N 2 ), hydrogen (H 2 ), and argon (Ar).

[0030] According to another aspect of the present invention, there is provided an apparatus for processing solid recovered fuel particles into a hydrogen-rich product gas stream, comprising:

[0031] - a calcining unit which calcines the solid recovered fuel particles into charred particles;

[0032] - a second mill, which grinds the charred particles into coarsely ground charred particles;

[0033] - a third metal removal unit, which includes an eddy current for removing metal residues from the coarsely ground charred particles;

[0034] - a third mill, which grinds the coarsely ground charred particles into finely ground charred particles;

[0035] - a gasification unit comprising an entrained flow gasifier for gasifying the finely ground charred particles into a raw synthesis gas;

[0036] A CO shift unit, which performs a CO shift reaction on the raw synthesis gas to produce a shifted synthesis gas;

[0037] - A gas cleaning unit comprising an adsorption unit for removing carbon dioxide and hydrogen sulfide from the shifted synthesis gas and a hydrogen separator for separating hydrogen from the purge gas to produce a hydrogen-rich product gas stream.

[0038] According to an embodiment, the plant further comprises a torrefaction gas processing unit which thermally cracks the torrefaction gas which may be produced in the torrefaction unit.

[0039] According to an embodiment, the hydrogen separator comprises a pressure swing adsorption system.

[0040] It should be noted that the individual features specified in the claims can be combined with each other in any desired technically reasonable way and form other embodiments of the invention. Figure 1 The present invention is further explained and preferred embodiments of the present invention are specifically described. Particularly preferred variations and technical fields of the present invention will now be explained in more detail with reference to the accompanying drawings. It should be noted that the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. The accompanying drawings are schematic and may not be drawn to scale. The accompanying drawings show:

[0041] Figure 1 Examples of apparatus for converting solid waste into a product gas stream comprising hydrogen;

[0042] Figure 2 Visualization of granulation equipment;

[0043] Figure 3 Examples of dryers used in granulation equipment;

[0044] Figure 4 Roasting unit and gasification unit;

[0045] Figure 5 roasting gas processing unit;

[0046] Figure 6 a carbon monoxide (CO) shift unit; and

[0047] Figure 7 Gas cleaning unit.

[0048] Figure 1 A pelletizing plant 100 is schematically shown, wherein solid recovered fuel pellets 117 produced in the pelletizing plant 100 are supplied to a plant 1 for converting solid waste into a gas comprising hydrogen, in particular into a synthesis gas comprising hydrogen. Pellets are produced from solid waste, such as municipal solid waste 103 and / or biomass, in the pelletizing plant 100, and the corresponding pellets 117 are then conveyed to the plant 1 and supplied to a torrefaction unit 200, in which the pellets are subjected to a substoichiometric oxidation at a temperature of 250° C. to 300° C. The torrefaction of the pellets produces charred pellets 201, which are gasified in a gasification unit 300. A further product of the torrefaction is a torrefaction gas 202, which is supplied to a torrefaction gas processing unit 400, which will be described with reference to the following. Figure 5The product of the torrefaction gas processing unit 400 is the torrefaction synthesis gas 401, and the product of the gasification unit 300 is the raw synthesis gas 301. The torrefaction synthesis gas 401 and the raw synthesis gas 301 include water vapor, carbon monoxide and hydrogen. Both the raw synthesis gas 301 and the torrefaction synthesis gas 401 are introduced into the CO shift unit 500, in which the carbon monoxide (CO) reacts with water vapor (H2O) to generate carbon dioxide (CO2) and hydrogen (H2):

[0049]

[0050] A shifted synthesis gas 501 having an increased hydrogen content compared to the synthesis gas 301, 401 is produced in the CO shift unit 500 and is passed to a gas cleaning unit 600, which separates hydrogen from a purge gas 602 to produce a hydrogen-rich product gas stream 601. The hydrogen content of the hydrogen-rich product gas stream 601 is at least 99.5% by volume. In the gas cleaning unit 600, carbon dioxide and hydrogen sulfide are separated from the remaining gas stream to produce a crude hydrogen stream, which is fed to a pressure swing adsorption system that allows hydrogen to pass through and absorbs all other molecules. The pressure is reduced by cycles, multiple absorbers are used simultaneously and purged with hydrogen. A purge gas is produced. At the same time, a hydrogen-rich product stream is produced, wherein the hydrogen content is more than 99.5% by volume. The granulation device 100 is preferably located off-site, i.e., located at a different location from the device 1 for converting solid waste into a gas containing hydrogen. The location of the pelletizing plant 100 off-site is advantageous because it reduces the quality of the municipal solid waste, since typically about 30% to 35% by weight of the water content of the municipal waste is evaporated. This significantly reduces the mass to be transported. In addition, since the pelletizing plant 100 allows for the centralized production of solid recovered fuel pellets and the subsequent transport of these pellets to the chemical plant in need, the footprint of the chemical plant (e.g., plant 1) can be reduced.

[0051] according to Figure 2 , the granulation apparatus 100 includes a pulverizer 102. Solid waste 103, such as municipal solid waste (MSW) to which biomass may be attached, is provided to the pulverizer 102, producing pulverized solid waste 104, which is conveyed by a first metal removal unit 105 including a magnet to remove iron residues 106 from the pulverized solid waste 104. Thereafter, the pulverized solid waste 104 is provided to a dryer 107, in which water 108 is removed from the pulverized solid waste 104. The pulverized solid waste 104 is then conveyed to a second metal removal unit 109 for removing metal residues 110 from the pulverized solid waste 104, the second metal removal unit 109 including a second magnet 139 for further removing ferrous metal and an eddy current for removing non-ferrous metal.

[0052] Thereafter, the minerals and stainless steel are removed as other residues 111 in the density classifier 112. In the density classifier 112, high-density residues such as stainless steel particles that cannot be removed by magnets or eddy currents are removed based on the density difference between the other residues 111 and the remainder of the pulverized solid waste 104. The same is true for minerals such as glass or stone, which are removed from the remainder of the pulverized solid waste 104 due to their density difference. A preferred example of the density classifier 112 is, for example, an air classifier.

[0053] After the removal of the other residues 111, the pulverized solid waste 104 is stripped of ferrous metals (e.g., ferrous residues 106 and metal residues 110), non-ferrous metals, stainless steel and minerals as other residues 111, etc., and moisture in the form of water 108. The remainder of the pulverized solid waste 104 is substantially the same as the solid waste 103 fed to the granulation plant 100. In particular, in the present granulation plant 100, there is no need to sort, for example, fine fractions of the solid waste 103 or chlorine-containing materials, such as polyvinyl chloride (PVC), etc. This means that the mass ratio of the pre-cleaned material stream 113 present downstream of the first metal removal unit 105, the second metal removal unit 109 and the density classifier 112 to the mass of the solid waste 103 fed to the granulation plant 1 is greater than in known methods.

[0054] Thereafter, the pre-cleaned material stream 113 is ground in a first mill 114, in particular to an average particle size of less than 25 mm, to produce a ground material stream 115. Subsequently, the ground material stream 115 is introduced into a pellet press 116 to produce solid recovered fuel particles 117.

[0055] Figure 3 It shows that Figure 1 An example of a dryer 107 used in a granulation apparatus 100 is shown. The dryer 107 for drying the pulverized solid waste 104 includes a kiln 118 for containing the pulverized solid waste 104, a scrubber 119 (also referred to as a scrubber), a heat pump 120, and a radiator 121. Air is drawn into the dryer 107 through a dryer air inlet 122, which is generally fluidly connected to the atmosphere. The drawn air may be passed through a dryer that is not in the Figure 3The vents shown in FIG. 1 are conveyed to a radiator 121. A dryer air inlet 122 is fluidly connected to a radiator air inlet 123 of the radiator 121 by a duct. The air conveyed to the radiator 121 is heated in the radiator 121 and leaves the radiator 121 through a radiator exhaust 124. The heated air is conveyed to a kiln 118, wherein a kiln air inlet 125 is fluidly connected to the radiator exhaust 124 by a duct. The shredded solid waste 104 is arranged inside the kiln 118, and the air conveyed to the kiln 118 flows through the shredded solid waste 104 and leaves the kiln 118 through a kiln exhaust 126. The temperature of the air entering the kiln 118 during the drying process is about 80° C., wherein the air leaving the kiln 118 exhibits a temperature of about 45° C. The relative humidity of the air leaving the kiln 118 is about 100%.

[0056] The kiln 118 is in fluid communication with the scrubber 119, wherein the kiln exhaust port 126 is in fluid communication with the scrubber air inlet port 127. Inside the scrubber 119, the air is in close contact with cold water. As a result, the moist warm air is cooled down, causing the moisture in the air to be condensed out and the latent heat to be converted into sensible heat of the water. This results in the water being heated from about 18°C ​​to about 25°C to 28°C and the air being cooled from about 28°C to 32°C to about 22°C to 24°C. The cooled air leaves the scrubber 119 through the scrubber exhaust port 128, which is in fluid communication with the dryer exhaust port 129.

[0057] Air leaving the scrubber 119 may also be delivered to the dryer air inlet 122 via a recirculation line 130, such that the scrubber exhaust 128 is fluidly connected to the dryer air inlet 122. A corresponding arrangement results in reduced energy consumption of the apparatus 100. The recirculation line 130 is not necessarily included in the apparatus 100 and may be omitted.

[0058] With respect to airflow, the radiator 121 is located downstream of the dryer air inlet 122 , the kiln 118 is located downstream of the radiator 121 , the scrubber 119 is located downstream of the kiln 118 , and the dryer exhaust 129 is located downstream of the scrubber 119 .

[0059] The scrubber 119 also includes a scrubber outlet 131 fluidly connected to the first heat pump inlet 132. The first heat pump outlet 133 is fluidly connected to the scrubber inlet 134. Therefore, water circulates between the scrubber 119 and the heat pump 120. Figure 3 The pump shown in FIG.

[0060] The water is heated in the scrubber 119 by the air entering the scrubber 119 through the scrubber air inlet 127, and the heated water leaves the scrubber 119 through the scrubber water outlet 131 and enters the heat pump 120 through the first heat pump inlet 132. Then, the heat energy of the water entering the heat pump 120 is transferred to another heat cycle implemented between the heat pump 120 and the radiator 121. The water entering the heat pump 120 exhibits a temperature of about 26° C. to 28° C., and the water leaving the heat pump 120 through the first heat pump outlet 133 exhibits a temperature of about 18° C.

[0061] The first heat pump outlet 133 is fluidly connected to the scrubber water inlet 134. Therefore, the water cooled in the heat pump 120 enters the scrubber 119 through the scrubber water inlet 134. Therefore, a heat cycle between the scrubber 119 and the heat pump 120 is achieved, wherein the heat energy of the water leaving the scrubber 119 is transferred to a second heat cycle between the heat pump 120 and the radiator 121 through the heat pump 120.

[0062] The second heat pump outlet 135 is fluidically connected and thus thermally connected to the radiator water inlet 136, and the radiator water outlet 137 is fluidically connected and thus thermally connected to the second heat pump inlet 138. Figure 3 The pump shown in FIG. 1 delivers between the heat pump 120 and the radiator 121. Thus, a second heat cycle is achieved between the heat pump 120 and the radiator 121.

[0063] Thermal energy from the water leaving the scrubber 119 is transferred to the radiator 121 via the heat pump 120 and to the air flowing through the radiator 121 from the radiator air inlet 123 to the radiator exhaust 124 .

[0064] The pelletizing device 100 of the present invention allows the production of solid recovered fuel particles from municipal solid waste without the need to separate parts of the municipal solid waste before starting the pelletizing process. Therefore, more municipal solid waste can actually be used to produce solid recovered fuel particles. The pelletizing device 100 and the method of the present invention can be used in particular for the production of solid recovered fuel particles that can be used to produce synthesis gas rich in hydrogen and / or carbon dioxide by roasting the solid recovered fuel particles and then performing gas treatment.

[0065] Figure 4An example of a roasting unit 200 and a gasification unit 300 is shown. In the roasting unit 200, solid recycled fuel particles 117 are provided to a furnace 203, which in this embodiment is a multi-hearth furnace. In the furnace 203, the solid recycled fuel particles 117 are roasted. The term roasting is understood to be a thermochemical treatment of the solid recycled fuel particles 117 at a temperature of 250° C. to 320° C. It is carried out at atmospheric pressure and without adding additional oxygen, for example without providing air. During the roasting process, the water contained in the solid recycled fuel particles evaporates, as do the volatiles contained in the solid recycled fuel particles 117. The biopolymers contained in the solid recycled fuel particles 117 partially decompose under the release of volatiles. The products of the roasting process are charred particles 201 and roasting gases 202.

[0066] The roasting gas 202 is provided to the roasting gas processing unit 400, which will be referred to below. Figure 5 is described. Because the metal portion of the solid recovered fuel particles 117 is not charred during the roasting process, the charred particles 201 include charred plastic or charred organic portions and possible metal inclusions. The charred particles 201 are provided to the second mill 204 for coarse grinding with a particle size of less than 10 mm. Thereafter, in the third metal removal unit 205 based on the eddy current removal process, the metal residues 206 that were not removed during the production of the solid recovered fuel particles 117 are removed. Both iron and non-iron residues are removed by the third metal removal unit 205. The remaining coarsely ground charred particles 207 are moved to the third mill 208, in which a process of finely grinding the coarsely ground charred particles 207 to finely ground charred particles 209 with a particle size of less than 500 μm [micrometers] is performed.

[0067] The finely ground charred particles 209 are provided as feedstock 303 to a gasification unit 300 including an entrained flow gasifier 302. Biomass 304 (e.g., dried sludge) may be finely ground to a particle size of the same order of magnitude as the particle size of the finely ground charred particles 209 and then added to the finely ground charred particles 209. The biomass 304 is ground in a corresponding fourth mill 305. The finely ground biomass 306 is then added to the feedstock 303 upstream of the entrained flow gasifier 302. Alternatively, but not in Figure 4 , the biomass 304 is ground together with the charred particles 201 and is thus introduced into the second mill 204 together with the charred particles 201 .

[0068] Feedstock 303 is supplied to entrained flow gasifier 302 together with oxygen-rich gas 307 having an oxygen content of at least 95% by volume, preferably at least 98% by volume, and in particular above 99.5% by volume. The gasification reaction occurs in a dense cloud of very fine particles in a co-current flow. The gasification is carried out at a temperature of 2000° C. and a pressure of 40 bar.

[0069] The obtained intermediate product gas 308 is provided to a quenching zone 309, in which the obtained intermediate product gas 308 is quenched with quenching water 310 preferably at a temperature of 180° C. to 220° C. The solid or molten solid solidifies due to the quenching process and forms a slag 311, which can be removed for use in civil construction. The generated raw synthesis gas stream 312 is provided to a water wash cooling tower 313, in which the moisture contained in the raw synthesis gas 312 tends to condense due to contact with water 314 at a temperature of 180° C. to 200° C. (lower than the temperature of about 214° C. of the raw synthesis gas 312). The cooled and washed raw synthesis gas 301 is provided to the CO shift unit 500. The excess exhaust water 315 is provided to a slurry stripper (not shown) for removing gas from the excess exhaust water 315. The make-up water 316 is provided by the low temperature heat recovery unit 524 of the CO shift unit 500 described below.

[0070] Figure 5 A torrefaction gas processing unit 400 is shown. The torrefaction gas 202 produced in the torrefaction unit 200 is introduced into the combustion chamber 402. In addition, a fuel gas 403 and an oxygen-enriched gas stream 404 are introduced into the combustion chamber 402. As the fuel gas 403, natural gas and / or site fuel gas (site fuel gas) are used. The fuel gas includes at least one of methane, ethane, nitrogen and hydrogen. For example, the so-called site fuel gas is produced in a steam cracker. The oxygen-enriched gas stream 404 contains at least 95 volume % [volume %] of oxygen, preferably at least 98 volume %, in particular 99.5 volume % or more. In particular, if the gasification unit 300 uses a parallel fluidized bed gasification, pure oxygen is easily obtained, that is, the oxygen-enriched gas stream 307 used in the gasification unit 300 can be provided by the same source as the oxygen-enriched gas stream 404. The combustion chamber 402 has a first inlet 436 for introducing the oxygen-enriched gas stream 404, a second inlet 437 for introducing the fuel gas, and a third inlet 438 for introducing the torrefaction gas 202. The obtained raw synthesis gas 301 is provided to the CO shift unit 500 .

[0071] Substoichiometric oxidation occurs in the combustion chamber 402, whereby larger hydrocarbon molecules originating from the torrefaction gas 202 and / or the fuel gas 403 are thermally cracked and converted into a synthesis gas 407 comprising carbon monoxide (CO), carbon dioxide (CO2), hydrogen (H2) and water (H2O). Due to the high moisture content of the torrefaction gas 202 (typically at least 50% by volume), the production of elemental carbon is suppressed, thereby suppressing the production of soot.

[0072] The temperature in the combustion chamber 402 is in the range of 1000° C. to 1200° C. After passing through the combustion chamber outlet 405, the synthesis gas 407 is quenched to a temperature of 730° C. to 770° C., preferably 740° C. to 760° C., in particular about 750° C., with the recycled synthesis gas 406 acting as quench gas. The synthesis gas 407 is introduced into a mixing chamber 408, in which the quenching process and the concomitant mixing with the recycled synthesis gas 406 take place, resulting in a quenched synthesis gas 409 cooled in the mixing chamber 408. The quenching is carried out in a quenching zone 439 having an inlet 440 for the recycled synthesis gas 406. The effect of the quenching process, i.e. the sudden reduction in temperature due to the introduction of the cooler recycled synthesis gas 406, is that any solid or molten solid present in the synthesis gas 407 is solidified. These solids can be introduced together with the torrefaction gas 202. Both the combustion chamber 202 and the mixing chamber 408 are internally insulated and unrefrigerated.

[0073] Downstream of the mixing chamber 408, the quenched synthesis gas 409 is introduced into a heat recovery system 410, in which the thermal energy or heat energy of the quenched synthesis gas 409 is transferred to a heat carrier 411, preferably hot oil, in a first heat exchanger 441. Downstream of the energy transfer to the heat carrier 411, further thermal energy is transferred to the boiler feed water 412 in a second heat exchanger 442, producing high-pressure steam 413, at least a portion of which is transferred through a fourth heat exchanger 414 to heat the circulating synthesis gas 406, preferably to a temperature of more than 200° C., in particular about 225° C. In the heat recovery system 410, in a superheater 443 downstream of the second heat exchanger 441 with the boiler feed water 412, further thermal energy from the quenched synthesis gas 409 is transferred to the low-pressure steam 415 to superheat it, thereby producing superheated low-pressure steam 416. The heat carrier is heated, for example, from a temperature of 300° C. to a temperature of 400° C., and can be used, for example, to indirectly heat the roasting unit 200. The high-pressure steam 413 has, for example, a pressure of 140 bar and a temperature of 350° C. when leaving the heat recovery system 410. The superheated low-pressure steam has a temperature of about 275° C. when leaving the heat recovery system 410, and is preferably used for the roasting process in the roasting unit 200. The quenched synthesis gas 409 leaves the heat recovery system 410 at a temperature above about 170° C. to avoid the formation of ammonium chloride (NH4Cl), which causes corrosion and / or scaling. In order to ensure a temperature of not less than about 170° C., boiler feed water 412 is introduced into the heat recovery system 410 above 140° C.

[0074] Downstream of the heat recovery system 410, the quenched syngas 409 is introduced into a wet scrubbing system 417 to remove solids and halogens (mainly chlorides). The wet scrubbing system 417 is a common wet scrubber. Used scrubbing water 418 is discharged from a sump 419 of the wet scrubbing system 417. Used scrubbing water 418 is transferred to a wastewater treatment device (not shown) for circulation. Clean syngas 420 leaves the wet scrubbing system 417 from the top 421 of the wet scrubbing system 417. The first portion of the clean syngas 420 is used as the circulating syngas 406, and is reheated and used for the quenching of the syngas 407 as described above. Using the clean syngas 420 as the circulating syngas 406 reduces the concentration of pollutants (such as solids, halogens, especially chlorides) in the quenched syngas 409, and avoids damage to the heat exchange surfaces in the heat recovery system, especially corrosion, and especially avoids corrosion of the surfaces used to superheat the low-pressure steam 415 into superheated low-pressure steam 416. Meanwhile, the high moisture content of 60 vol% or more increases the heat capacity of the circulating synthesis gas 406 , and thus increases the cooling efficiency during the quenching process. The circulating synthesis gas 406 is compressed by the compressor 423 .

[0075] The second part, i.e. the remaining part 424, of the cleaned syngas 420 is introduced into a two-stage water-wash cooling tower 422. Due to the close contact with the cooler water in the tower 422, the moisture in the syngas 424 is condensed. The corresponding condensation heat heats the wash water in the tower 422. The wash water 426 from the tank 425 is provided to the heat pump 427 for cooling, for example, from a temperature of about 85°C to a temperature of 75°C. In the heat pump 427, low-pressure steam is generated, which is preferably used in the roasting unit 200 for process control. Most of the wash water 426 is introduced into the tower 422 centrally, distributed in the first stage 428 and the second stage 429 of the tower 422. A small part of the wash water 426 is further cooled by the air cooler 430, preferably to a temperature of about 25°C, so that the temperature of the syngas 424 when leaving the tower 422 reaches a temperature of about 30°C. In the cooling of the syngas 422, about 60% of the mass is removed in the form of water. The excess wash water 431 is partially used as make-up water 432 for the wet scrubbing system 417. The excess wash water 431 may be directed as bleed water 433 to a stripper system (not shown) in which gases, in particular ammonia (NH3), carbon dioxide (CO2) and hydrogen sulfide (H2S) are stripped from the bleed water 433.

[0076] The synthesis gas conveying device 434, preferably a fan or a blower, is used to convey the roasted synthesis gas 401 leaving the tower 422 to the CO conversion unit 500 (see Figure 1 ) and / or flare 435. Syngas delivery device 434 generates negative pressure, which pulls quenched syngas 406 through heat recovery system 410.

[0077] The torrefaction gas processing unit 400 allows for chemical recovery of torrefaction gases 202 generated, for example, by torrefaction of solid recovered fuel (SRF) particles 117 without the need to combust the torrefaction gases 202 .

[0078] Figure 6 A carbon monoxide (CO) shift unit 500 included in the apparatus 1 is schematically shown. In the carbon monoxide shift unit 500, a carbon monoxide (CO) shift reaction occurs, wherein carbon monoxide (CO) reacts with water (H2O) to form carbon dioxide (CO2) and hydrogen (H2):

[0079]

[0080] The reaction is in chemical equilibrium, which can be affected in the usual way in the direction of reactants (educts) or products, such as by using the use and concentration of corresponding temperature and specific catalysts. Since the reaction is endothermic, water is usually provided in the form of water vapor. In order to transfer the chemical equilibrium to the product side to increase the generation of hydrogen, it has been found that the molar ratio of steam to carbon monoxide is about 2.3 to 2.7, particularly about 2.5 is advantageous. Steam is preferably provided at a pressure higher than the pressure (preferably about 40 bar) at which the shift reaction occurs. If the molar ratio of steam to carbon monoxide is 2.5, then 1.5 moles of steam will remain for every 1 mole of carbon dioxide remaining in the reactor. This causes the product gas of the CO shift reaction to contain a large amount of water. When this product gas is cooled, this will cause a large amount of condensation, and therefore, when the product gas is cooled to ambient temperature, a large amount of low-level heat is generated in the cooling system. Most of this energy is usually discarded, resulting in low energy efficiency.

[0081] The raw synthesis gas 301 produced by the gasification unit 300 is introduced into the high-pressure washing unit 502. The high-pressure washing unit 502 is a conventional wet washing unit, in which, for example, higher hydrocarbons are removed from the raw synthesis gas 301. The high-pressure washing unit 502 is supplied with feed water 503, which is condensed water 508 from the low-temperature heat recovery to be described later. The water 505 collected in the tank 504 of the high-pressure washing unit 502 is transported to the discharge water conduit 507 by the conveying device 506. Excess condensed water 508 that is not required as feed water 503 is also transported to the discharge water conduit 507. The clean synthesis gas 509 produced in the high-pressure washing unit 502 is provided to the first heat exchanger 518 downstream of the high-pressure washing unit 502. The term conveying device in this article is understood to be a pump and / or a compressor. While the raw synthesis gas 301 is cleaned in the high-pressure washing unit 502, the moisture content of the clean synthesis gas 509 can be controlled.

[0082] The roasting synthesis gas 401 produced in the roasting gas processing unit 400 is transported to the saturation tower 510 through the conveying device 511. The roasting synthesis gas 401 is compressed by the conveying device 511, preferably compressed to a pressure of 40 bar. The conveying device 511 may include several compressors with intercoolers, which provide multi-stage intercooling compression of the roasting synthesis gas 401. Similarly, the purge gas 602 from the gas cleaning unit 600 is also transported to the saturation tower 510 through the conveying device 512. The purge gas 602 is compressed by the conveying device 512, preferably compressed to a pressure of 40 bar. The conveying device 512 may include several compressors with intercoolers, which provide multi-stage intercooling compression of the purge gas 602. The saturation tower 510 is a conventional wet scrubber, which is provided with process water 513 from the low-temperature heat recovery unit 524 described later through the conveying device 514. The water 515 collected in the tank 516 of the saturation tower 510 is used as process water for the low temperature heat recovery unit 524 described below. The roasted synthesis gas 401 and the purge gas 602 are mixed by the saturation tower 510, and moisture is added to the resulting saturation tower product gas 517. The moisture content of the saturation tower product gas 517 can be controlled according to the operating parameters of the saturation tower, that is, in particular, the water flow and water temperature.

[0083] The saturator product gas 517 is supplied to a first heat exchanger 518 together with the clean syngas 509. In the first heat exchanger 518, energy is transferred from the high temperature CO shift reactor off-gas 519 to the clean syngas 509 and the saturator product gas 517, which are combined downstream of the first heat exchanger 519 into a combined syngas stream 520. By heat exchange in the first heat exchanger 518, the respective high temperature CO shift reactor off-gas 519 is cooled, while the clean syngas 509 and the purified gas stream 517 are heated. Preferably, the saturator 510 is driven in such a way that the molar ratio of water vapor to carbon monoxide of the combined syngas stream 520 is from 2.0 to 3.0, preferably from 2.4 to 2.6, in particular about 2.5.

[0084] The combined syngas stream 520 is provided to a high temperature CO shift reactor 521 downstream of the first heat exchanger 518, in which the above-mentioned shift reaction is carried out. The high temperature CO shift reactor exhaust gas 519 has a reduced water / steam and carbon monoxide content, and an increased hydrogen (H2) content compared to the combined syngas stream 520. As described below, the high temperature CO shift reactor exhaust gas 519 is directed through several heat exchangers to reduce its temperature, including the first heat exchanger 518 to a low temperature CO shift reactor 522 where the above-mentioned CO shift reaction occurs. The hydrogen (H2) content of the low temperature CO shift reactor exhaust gas 523 is increased compared to the high temperature CO shift reactor exhaust gas 519 entering the low temperature CO shift reactor 522.

[0085] The low temperature CO shift reactor exhaust gas 523 is directed through a low temperature heat recovery unit 524 downstream of the low temperature CO shift reactor 522. In the low temperature heat recovery unit 524, the heat content of the low temperature CO shift reactor exhaust gas 523 is used to increase the temperature of several water streams. After entering the low temperature heat recovery unit 524, the low temperature CO shift reactor exhaust gas 523 is then directed through a second heat exchanger 525, a third heat exchanger 526, a fourth heat exchanger 527, a fifth heat exchanger 528, and a sixth heat exchanger 529. When passing through these heat exchangers 524, 525, 526, 527, 528, 529, the temperature of the low temperature CO shift reactor exhaust gas 523 is steadily reduced, and then leaves the low temperature heat recovery unit 524 as a synthesis gas stream 530, and optionally passes through an air cooler 531 if necessary. Thereafter, the synthesis gas stream 530 is provided to the gas cleaning unit 600 as described above.

[0086] First, in the second heat exchanger 525, the heat content of the synthesis gas stream 530 is used to heat the feed water 508 to be used in the gasification unit 300. For example, this water 508 can thus be heated from 158°C to 205°C. Second, in the third heat exchanger 526, water is heated, which can be used, for example, to produce high-pressure steam. For example, water is typically heated from 155°C to 200°C. Third, in the fourth heat exchanger 527, process water 513 is typically heated from 135°C to 158°C, which is used in the saturation tower 510. This water can be further used as feed water 508, especially after passing through the second heat exchanger 525. In the fourth heat exchanger 527, the low-temperature CO shift reactor exhaust gas 523 is cooled below its dew point, so that a large amount of condensation heat is released and used for corresponding heat transfer. Fourth, in the fifth heat exchanger 528, the boiler feed water 536 is typically heated from 35°C to 155°C, which is preferably used to prepare high-pressure steam. Fifth, in the sixth heat exchanger 529 , water is heated typically from 25° C. to 135° C. for gasification of the charred particles 201 in the gasification unit 300 .

[0087] The feed water 508 for the gasification unit 300 is at least a portion of the water 515 collected in the tank 519 of the saturation tower 510 as described above. The water 515 collected in the tank 516 of the saturation tower 510 enters the fourth heat exchanger 527. Water 521 from a wastewater treatment unit (not shown) may be mixed with the water 515 after passing through the sixth heat exchanger 529. Downstream of the second heat exchanger 527, the heated fourth heat exchanger water offstream 533 is partly used as process water 513 from low temperature heat recovery in the saturation tower 510, and partly directed through the second heat exchanger 525 to be used as condensed water 508 in the downstream portion of the second heat exchanger 525, partly as feed water 503 in the high pressure washing unit 502, and partly as process water in the roasting unit 200. Another portion of the water downstream of the sixth heat exchanger 529 is used as condensate 534, for example, provided to a water stripper. Other water, for example external high-pressure boiler feed water 535 generated for applications outside the plant 1, is led through the fifth heat exchanger 528 to be used partly as boiler feed water 536, for example in the gasification unit 300 and / or for generating low-pressure steam and / or in the roasting unit 200. Another part of the boiler feed water 535 is led through the second heat exchanger 526 downstream of the fifth heat exchanger 528. Thereafter, it passes through the seventh heat exchanger 537.

[0088] The CO shift unit 500 as part of the plant 1 for converting solid waste into a product gas stream comprising hydrogen allows energy-efficient use of low-temperature thermal energy in the low-temperature heat recovery unit 524 for heating a process water stream used in the plant 1 .

[0089] Figure 7 The gas cleaning unit 600 is shown in more detail. The shifted synthesis gas 501 as the output of the CO shift unit 500 is introduced into the gas cleaning unit 600 and subsequently passes through a hydrogen sulfide adsorption unit 603 and a carbon dioxide adsorption unit 604. Thereafter, it passes through a pressure swing adsorption unit 605, wherein by pressure swing adsorption, a product gas stream 601 rich in hydrogen, preferably pure hydrogen, with a hydrogen content of at least 99.5% by volume is produced. Typically, a single adsorber of the pressure swing adsorption unit 605 is purged with hydrogen, producing a purge gas 602.

[0090] The hydrogen sulfide collected in the hydrogen sulfide adsorption unit 603 is used to produce sulfur 606 by the Claus process. The carbon dioxide 607 adsorbed in the carbon dioxide adsorption unit 603 can be extracted therefrom and used in other processes.

[0091] The method and apparatus 1 for converting solid recovered fuel particles 117 made from municipal solid waste 103 allows the municipal solid waste 103 to be converted into high yield hydrogen instead of landfilling or incinerating the municipal solid waste 103. The hydrogen-rich product gas stream 601 can be used as a feedstock for chemical reactions or for storing energy in a releasable manner.

[0092] Reference numerals

[0093] 1Apparatus for converting solid waste into gas containing hydrogen

[0094] 100 Granulation equipment

[0095] 102 Crusher

[0096] 103 Solid waste

[0097] 104 Crushed solid waste

[0098] 105 First Metal Removal Unit

[0099] 106 Iron residue

[0100] 107 Dryer

[0101] 108 Water

[0102] 109 Second Metal Removal Unit

[0103] 110 Metal Residues

[0104] 111 Other residues

[0105] 112 Density Classifier

[0106] 113 Pre-cleaning material flow

[0107] 114 First Mill

[0108] 115 Grinding Material Flow

[0109] 116 Pellet Press

[0110] 117 Solid recovered fuel pellets

[0111] 118 Kiln

[0112] 119 Scrubber

[0113] 120 Heat Pump

[0114] 121 Radiator

[0115] 122 Dryer air inlet

[0116] 123 Radiator air inlet

[0117] 124 Radiator exhaust port

[0118] 125 Kiln air inlet

[0119] 126 Kiln exhaust port

[0120] 127 Scrubber Air Inlet

[0121] 128 Scrubber Exhaust

[0122] 129 Dryer exhaust port

[0123] 130 Recirculation line

[0124] 131 Scrubber Outlet

[0125] 132 First heat pump inlet

[0126] 133 First heat pump outlet

[0127] 134 Washing tower water inlet

[0128] 135 Second heat pump outlet

[0129] 136 Radiator water inlet

[0130] 137 Radiator outlet

[0131] 138 Second heat pump inlet

[0132] 139 Second Magnet

[0133] 200 Roasting unit

[0134] 201 Burnt Particles

[0135] 202 Roasting gas

[0136] 203 Furnace

[0137] 204 Second Grinding Mill

[0138] 205 Third Metal Removal Unit

[0139] 206 Metal Residues

[0140] 207 Coarsely ground charred particles

[0141] 208 The Third Mill

[0142] 209 Finely ground charred particles

[0143] 300 Gasification Unit

[0144] 301 Crude Synthesis Gas

[0145] 302 Entrained Flow Gasifier

[0146] 303 Raw Materials

[0147] 304 Biomass

[0148] 305 Fourth Mill

[0149] 306 Finely ground biomass

[0150] 307 Oxygen-enriched air flow

[0151] 308 Intermediate Product Gas

[0152] 309 Sudden Cooling Zone

[0153] 310 Quenching Water

[0154] 311 Slag

[0155] 312 Raw synthesis gas

[0156] 313 Water Washing Cooling Tower

[0157] 314 Water

[0158] 315 Excessive drainage water

[0159] 316 Make-up Water

[0160] 400 Roasting Gas Processing Unit

[0161] 401 Syngas

[0162] 402 Combustion Chamber

[0163] 403 Fuel Gas

[0164] 404 Oxygen-enriched air flow

[0165] 405 Combustion chamber outlet

[0166] 406 Recycled Syngas

[0167] 407 Syngas

[0168] 408 Mixing Chamber

[0169] 409 Quenched Syngas

[0170] 410 Heat Recovery System

[0171] 411 Heat carrier

[0172] 412 Boiler feed water

[0173] 413 High Pressure Steam

[0174] 414 Fourth heat exchanger

[0175] 415 Low Pressure Steam

[0176] 416 Superheated Low Pressure Steam

[0177] 417 Wet Scrubber System

[0178] 418 Used washing water

[0179] 419 slots

[0180] 420 Clean Syngas

[0181] 421 Top

[0182] 422 Two-stage water washing cooling tower

[0183] 423 Compressor

[0184] 424 Cleaning the remainder of the synthesis gas

[0185] 425 slots

[0186] 426 Washing water

[0187] 427 Heat Pump

[0188] 428 First Level

[0189] 429 Second Level

[0190] 430 Air Cooler

[0191] 431 Excessive washing water

[0192] 432 Make-up water

[0193] 433 Drain water

[0194] 434 Synthesis Gas Transportation Device

[0195] 435 Torch

[0196] 436 First Entrance

[0197] 437 Second Entrance

[0198] 438 Third Entrance

[0199] 439 Sudden Cooling Zone

[0200] 440 Entrance to the quenching zone

[0201] 441 First heat exchanger

[0202] 442 Second heat exchanger

[0203] 443 Superheater

[0204] 500 CO conversion unit

[0205] 501 Shift Synthesis Gas

[0206] 502 High Pressure Washing Unit

[0207] 503 Feed water

[0208] 504 slots

[0209] 505 Water

[0210] 506 Conveyor

[0211] 507 Discharge water pipe

[0212] 508 Condensation

[0213] 509 Clean Syngas

[0214] 510 Saturation Tower

[0215] 511 Conveyor

[0216] 512 Conveyor

[0217] 513Process water from low temperature heat recovery

[0218] 514 Conveyor

[0219] 515 Water

[0220] 516 slots

[0221] 517 Saturation tower product gas

[0222] 518 First Heat Exchanger

[0223] 519 High temperature CO shift reactor exhaust gas

[0224] 520 Combined high temperature synthesis gas stream

[0225] 521 High Temperature CO Shift Reactor

[0226] 522 Low Temperature CO Shift Reactor

[0227] 523 Low temperature CO shift reactor exhaust gas

[0228] 524 Low temperature heat recovery unit

[0229] 525 Second heat exchanger

[0230] 526 Third heat exchanger

[0231] 527 Fourth heat exchanger

[0232] 528 Fifth heat exchanger

[0233] 529 Sixth heat exchanger

[0234] 530 Synthesis gas flow

[0235] 531 Air Cooler

[0236] 532 Wastewater treatment unit

[0237] 533 Fourth heat exchanger water outflow

[0238] 534 Condensate

[0239] 535 High pressure boiler feed water

[0240] 536 Boiler feed water

[0241] 537 Seventh Heat Exchanger

[0242] 538 Saturated tower product gas

[0243] 600 Gas Cleaning Unit

[0244] 601 Hydrogen-enriched product gas

[0245] 602 Purge gas

[0246] 603 Hydrogen sulfide adsorption device

[0247] 604 Carbon dioxide adsorption device

[0248] 605 Pressure Swing Adsorption Unit

[0249] 606 Sulfur

[0250] 607 Carbon dioxide

Claims

1. A method for processing solid recovered fuel particles (117) made from municipal solid waste (103), comprising the following steps: a) roasting the particles (117) at a roasting temperature of 250° C. to 300° C. to produce charred particles (201) and roasting gas (202); b) grinding the charred particles (201) into coarsely ground charred particles (207) in a first grinding step, wherein the charred particles (201) are ground to a particle size of less than 10 mm; c) removing metal residues (206) from the coarsely ground charred particles (207); d) grinding the coarsely ground charred particles (207) into finely ground charred particles (209), wherein the coarsely ground charred particles (207) are ground to a particle size of less than 500 μm [micrometers]; e) gasifying the finely ground charred particles (209) into a raw synthesis gas (301) in an entrained flow gasification process; f) performing a CO shift reaction on the raw synthesis gas (301) to produce a shifted synthesis gas (501); g) removing carbon dioxide and hydrogen sulfide from the shifted synthesis gas (501) to produce synthesis gas; and h) producing a hydrogen-rich product gas stream (601) by purifying the synthesis gas, In step h), hydrogen is separated from the synthesis gas to produce a hydrogen-rich product gas stream (601) and a purge gas (602), wherein the roasting gas (202) produced in step a) is thermally cracked to produce a roasting synthesis gas (401), and the roasting synthesis gas (401) is mixed with the raw synthesis gas (301) produced in step e) and the purge gas (602) produced in step h) before step f).

2. The method of claim 1, wherein in step c), the metal residues (206) are removed using eddy current technology.

3. The method according to claim 1 or 2, wherein in step h), carbon dioxide (CO2) and hydrogen sulfide (H2S) are removed from the synthesis gas by adsorption.

4. The method of claim 1 or 2, wherein a portion of the purge gas (602) is used as fuel gas.

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