JP4744971B2 - Low quality waste heat recovery system - Google Patents

Description

  The present invention relates to a low-quality waste heat recovery system that effectively recovers low-quality waste heat with a low rate of exergy.

Carbon dioxide (CO ₂ ) is known as one of room temperature effect gases that cause global warming, and there is an increasing interest in reducing carbon dioxide emissions, which is one of the recent environmental pollution countermeasures.

  Effective use of unused energy, improvement of energy conversion efficiency, and separation and recovery / sequestration of carbon dioxide are effective in reducing carbon dioxide, and it has not been used as one of the effective uses of unused energy. The chemical recovery of low-quality waste heat with a low energy rate has been studied.

  For example, as described in Patent Document 1, a method of chemically converting energy using methanol has been proposed.

  Methanol can produce high-quality energy hydrogen by steam reforming even with low-quality waste heat of about 250 ° C. using a copper-zinc catalyst.

  Hydrogen theoretically has an exergy efficiency of 83%, which is lower than the methanol exergy efficiency of 92%, and has the characteristic of having essentially less exergy loss when converted to electrical energy. In particular, since hydrogen can be applied to a fuel cell that directly converts electric energy, the energy conversion efficiency, that is, the power generation efficiency can be greatly improved even in a small-scale power generation system.

  The steam reforming reaction of methanol is an endothermic reaction, and the heat energy of waste heat can be taken in as chemical energy of the hydrogen-rich reformed gas.

  Recently, dimethyl ether (hereinafter referred to as DME) has been attracting attention as an alternative fuel for light oil, but this DME can also generate a steam reforming reaction at 300 ° C. or lower and generate hydrogen. Similarly, the heat energy of low-quality waste heat can be recovered chemically.

  In the industry, waste heat at about 300 ° C. is about 4 to 8% of the total waste heat. For this reason, steam reforming of fuel is effective for energy conversion of these waste heats.

  Generally, in a waste incineration facility, it is difficult to generate high-temperature steam due to the generation of dioxins and corrosion in the furnace. Although it is possible to generate low temperature steam at about 300 ° C., the power generation efficiency is low in this temperature range, so in practice it is mostly used as hot water. Super garbage power generation combined with a gas turbine using natural gas as a fuel is a highly efficient power generation method, but it is still in widespread use.

  On the other hand, in fuel cells known as highly efficient energy conversion methods, hydrogen is indispensable as a fuel gas, and generally hydrocarbon fuels cannot be directly used for electrochemical reactions. Hydrogen is generated. The energy used to generate hydrogen in the reformer is a major factor that reduces the power generation efficiency of the fuel cell system. However, if hydrogen generated using external waste heat is used, the energy can be effectively used. Is possible.

  Carbon dioxide separation and ablation technologies are also effective methods for reducing carbon dioxide, but carbon dioxide is often the final emission in energy conversion, and new energy is used to separate and recover carbon dioxide. This will further increase carbon dioxide emissions.

  In addition, carbon dioxide is often present in a state of being diluted to 10% or less in the combustion exhaust, and the amount of gas processing for separation and recovery becomes enormous, making it difficult to separate and recover carbon dioxide. Has become a major factor.

In order to overcome such problems, Non-Patent Document 1 has recently been proposed in which fuel is steam reformed and carbon dioxide is removed from the reformed gas before combustion.
JP-A-5-170401 AIChE Journal (1999), Vol. 45, no. 2, pp. 248-256

  As described above, in industrial equipment and waste incineration facility recovery, which is low-quality waste heat, low-quality waste heat is hardly used except for heat utilization. As one effective utilization method of low-quality waste heat, a system that uses steam reforming and converts it into chemical energy has been proposed.

  However, no effective use of unused energy including carbon dioxide separation and recovery has been proposed yet. Today, where environmental pollution needs to be suppressed, the realization of carbon dioxide separation and recovery technology as soon as possible is desired.

  The present invention has been made on the basis of such a background art, and by using the low-quality waste heat in a cascade manner, the low-quality is designed so that hydrogen production and carbon dioxide separation can be performed simultaneously. The purpose is to provide a waste heat recovery system.

In order to achieve the above object, a low-quality waste heat recovery system according to the present invention uses a waste heat gas as a heat source and reforms dimethyl ether to produce hydrogen gas as described in claim 1. The recovery system includes a low-quality waste heat gas route system that allows waste heat gas to flow, and a hydrogen purification system that purifies hydrogen gas from a reformed gas that is branched from the low-quality waste heat gas route system and reformed from dimethyl ether. The hydrogen purification system includes, in order along the flow of the reformed gas, a carbon monoxide converter, a first pressure temperature swing adsorption device, an off gas system, a carbon dioxide absorber, a second pressure temperature swing adsorption device, and a high It is equipped with a purity hydrogen gas recovery device .

In order to achieve the above-mentioned object, the low-quality waste heat recovery system according to the present invention is configured so that the low-quality waste heat gas route system sequentially changes the reformer, the evaporation from the higher waste heat gas temperature toward the lower one. A regenerator, a regenerator, and a dimethyl ether vaporizer.

In order to achieve the above-mentioned object, the low-quality waste heat recovery system according to the present invention is configured so that the low-quality waste heat gas route system sequentially changes the reformer, the evaporation from the higher waste heat gas temperature toward the lower one. A heater , a heating medium heater, a preheater, and a dimethyl ether vaporizer.

Further, low quality waste heat recovery system according to the present invention, dioxide in order to achieve the above object, the carbon dioxide absorber provided in the hydrogen purification system is provided between the regenerator provided in low quality waste heat gas route system A carbon dioxide absorbent circulation system for circulating the carbon absorbent is provided.

The low-quality waste heat recovery system according to the present invention is a low-quality waste heat recovery system in which waste heat gas is used as a heat source and dimethyl ether is reformed to generate hydrogen gas in order to achieve the above-mentioned object. A low-quality waste heat gas route system for flowing through, and a hydrogen purification system for purifying hydrogen gas from a reformed gas that is branched from the low-quality waste heat gas route system and reformed dimethyl ether, wherein in order along the flow of the reformed gas, carbon monoxide shift converter, the regenerator comprises a carbon dioxide absorber and hydrogen crude recovery equipment, heating medium heater provided in the low-quality waste heat gas route system, the A heat medium circulation system for circulating the heat medium between the regenerator provided in the hydrogen purification system is provided.

In the low-quality waste heat recovery system according to the present invention , the regenerator includes a high-purity carbon dioxide recovery unit in order to achieve the above-described object.

  The low-quality waste heat recovery system according to the present invention includes a low-quality waste heat gas route system for passing a low-quality waste heat gas, a hydrogen gas from a reformed gas that is branched from the low-quality waste heat gas route system and reformed dimethyl ether Since a hydrogen purification system for purifying water is provided, hydrogen production and carbon dioxide separation can be performed simultaneously, and energy can be effectively utilized to save energy.

  Hereinafter, an embodiment of a low-quality waste heat recovery system according to the present invention will be described with reference to the drawings and the reference numerals attached in the drawings.

  FIG. 1 is a schematic system diagram showing a first embodiment of a low-quality waste heat recovery system according to the present invention.

  The low-quality waste heat recovery system according to the present embodiment includes a low-quality waste heat gas route system 1, and the reformer in order from the higher waste heat gas temperature of the low-quality waste heat gas route system 1 toward the lower one. 2, an evaporator 3, a regenerator 4, and a DME (dimethyl ether) vaporizer 5.

  Further, the low-quality waste heat recovery system according to the present embodiment is provided with a hydrogen purification system 2a branched from the reformer 2 of the low-quality waste heat gas route system 1, and the one having the higher reformed gas temperature of the hydrogen purification system 2a. The carbon dioxide transformer 6, the cooler 7, the carbon dioxide absorber 8, the hydrogen crude refining and recovering device 9, and the high purity carbon dioxide recovering device 10 are provided in order from the lowest to the lowest.

  In the low-quality waste heat recovery system having such a configuration, liquid DME having a vapor pressure of about 0.5 MPa at room temperature is pressurized by a pump (not shown) and sent to the DME vaporizer 5.

  The DME vaporizer 5 vaporizes liquid phase DME using the waste heat gas as a heat source, for example, into 40 ° C. DME gas.

  On the other hand, the water supplied to the evaporator 3 is vaporized by using the waste heat gas as a heat source, for example, steam at 200 ° C., and is sent to the reformer 2 together with the DME gas supplied from the DME vaporizer 5.

The reformer 2 steam-reforms the DME gas based on the reaction formula shown by the formula (1) to generate hydrogen-rich reformed gas H ₂ , carbon monoxide CO, carbon dioxide CO _{2 and the} like.

[Chemical 1]
_{C 2 H 6 O + H 2} O → 4H 2 + 2CO-204KJ / mol + DME ...... (1)
Further, the reformer 2 reacts carbon monoxide CO with carbon dioxide CO ₂ based on the formula (2) simultaneously with the reaction based on the reaction formula shown by the above-described formula (1).

[Chemical 2]
CO + H ₂ O → H + CO ₂ +41 KJ / mol (2)
The remaining carbon monoxide CO that has not been sufficiently reacted in the reformer 2 undergoes a shift reaction based on the formula (2) in the carbon monoxide converter 6 to generate hydrogen and carbon dioxide gas. To do.

  The above formula (2) is an exothermic reaction and tends to proceed at a low temperature in terms of chemical equilibrium, but it is desired to react at a temperature of about 250 ° C. from the viewpoint of the reaction rate. For this reason, in this embodiment, the reformed gas is sent to the carbon monoxide converter 6 at a temperature of 250 ° C., for example, and an exothermic reaction is performed here.

After the exothermic reaction of the reformed gas, the generated carbon dioxide CO ₂ has a high temperature of about 280 ° C., so it is cooled by the cooler 7 until the temperature reaches about 90 ° C. and absorbed by the carbon dioxide absorber 8. The

The absorbent used for absorbing the carbon dioxide CO ₂ by the carbon dioxide absorber 8 is selected from amino acid, alkaline carbonate aqueous solution, and the like. The absorbent is circulated using a carbon dioxide absorbent circulation system 13 provided between the carbon dioxide absorber 8 and the regenerator 4.

Among the reformed gases, the carbon dioxide absorber 8 in which carbon dioxide CO ₂ is absorbed by the absorbent produces the remaining 95% or more of crude purified hydrogen gas, and the generated crude purified hydrogen gas is a crude hydrogen refiner / collector. 9 to collect.

  The hydrogen gas recovered by the crude hydrogen refining / recovering device 9 is supplied to, for example, a power plant as it is, or after being purified by increasing the purity using the pressure swing adsorption method, for example, is supplied to the power plant.

  The power plant is applicable to internal combustion engines such as gas turbines and gas engines, and fuel cells. However, considering that the crude hydrogen gas rich in hydrogen concentration is suitable for increasing the output, the fuel cell is preferably selected.

On the other hand, the carbon dioxide CO ₂ absorbed by the absorbent of the carbon dioxide absorber 8 is supplied to the regenerator 4 where high-purity carbon dioxide CO ₂ is generated using waste heat gas as a heat source. Pure carbon dioxide CO ₂ is recovered by the high purity carbon dioxide collector 10.

  Next, the heat and material balance of the low-quality waste heat recovery system according to this embodiment will be described.

  First, in the reaction based on the formula (1) and the formula (2) generated in the reformer 2 and the carbon monoxide converter 6, 3 mol of water is required for 1 mol of DME. In order to prevent disqualification of the catalyst due to carbon deposition in the mass container 2, the amount of water is required to be 3 mol or more.

  On the other hand, in both formulas (1) and (2), the reaction easily proceeds if the amount of water is increased, but the excess water that does not contribute to the reaction lowers the concentration of the aqueous solution in the carbon dioxide absorber 8.

  Moreover, if there is much water, the waste heat gas temperature of the exit of the evaporator 3 will fall, and the regenerator 4 cannot be supplied with the required heat.

  In consideration of such an event, about 3 to 5 mol of water is appropriate for 1 mol of DME.

  Assuming that DME = 1 mol / s is supplied to the DME vaporizer 5 as a standard for evaluating the heat and mass balance, the temperatures in the four waste heat recovery devices of the reformer 2, the evaporator 3, the regenerator 4, and the DME vaporizer 5 are as follows. FIG. 2 and FIG. 3 show the level limit, the heat adjustment chart of the recovered heat quantity, and the design essential points.

  In these figures, the reformer 2 is located on the most upstream side, and only the input temperature level limitation to the evaporator 3 needs to be considered.

  However, since the recovered heat amount of the evaporator 3 and the regenerator 4 is approximately equal to or higher than that of the reformer 2, all of the restrictions in FIG. 3 cannot be satisfied unless the waste heat gas has an appropriate flow rate.

  The waste heat gas is generally considered to be combustion air or water vapor. FIG. 2 shows the temperature drop when the specific heat of air is assumed, the waste heat gas temperature is 320 ° C., and the flow rate is 2.5 kg / s. In this case, all four conditions are satisfied. If the flow rate of the waste heat gas is higher than 2.5 kg / s, it can be maintained at an appropriate temperature using the cooling means, but conversely, if it is low, the system cannot be realized.

  Therefore, the minimum flow rate ratio between DME and waste heat gas is determined by the limitation of FIG.

  In this flow sheet, the pressure is 0.9 MPa. However, if the final form of hydrogen is a gas cylinder, it can be reformed at a higher pressure in order to reduce the compression power. Even in this case, there is no significant difference in the amount of recovered heat as the optimum temperatures of the evaporator 3 and the DME vaporizer 5 become somewhat higher.

  As described above, in this embodiment, the reformer 2, the evaporator 3, the regenerator 4, and the DME vaporizer 5 are arranged in order from the higher temperature of the waste heat gas to the lower temperature, and 1 mol of DME is disposed. Since the water is set to 3 mol or more and the waste heat gas is set to 2.5 kg or more, it is possible to realize a system that generates hydrogen while recovering low-quality waste heat and can simultaneously separate and recover carbon dioxide. it can.

  FIG. 4 is a schematic system diagram showing a second embodiment of the low-quality waste heat recovery system according to the present invention.

  In addition, the same code | symbol is attached | subjected to the component same as the component shown by 1st Embodiment, or the component to react, and duplication description is abbreviate | omitted.

  In the low-quality waste heat recovery system according to the present embodiment, the reformed gas exiting the carbon monoxide converter 6 has a high temperature of about 280 ° C., and when supplied to the carbon dioxide absorber 8, the temperature must be lowered to 90 ° C. Rather, it is intended to effectively recover surplus energy during this period.

  That is, the energy consumption required to lower the temperature from 280 ° C. to 90 ° C. is 44 kW per 1 mol / s DME.

  In this embodiment, paying attention to such points, a preheater 11 is provided between the carbon monoxide converter 6 and the carbon dioxide absorber 8 of the hydrogen purification system 2a, and the carbon monoxide converter is provided in the preheater 11. The reformed gas from 6 is used as a heat source, water is supplied for heat exchange, and hot water after the heat exchange is supplied to the evaporator 3, a hot water tank (not shown), etc., to effectively recover surplus energy. .

  As described above, in this embodiment, the preheater 11 is provided between the carbon monoxide transformer 6 and the carbon dioxide absorber 8, and the warm water generated by the preheater 11 is used. It can be recovered effectively.

  FIG. 5 is a schematic system diagram showing a third embodiment of the low-quality waste heat recovery system according to the present invention.

  In addition, the same code | symbol is attached | subjected to the component same as the component shown by 1st Embodiment and 2nd Embodiment, or a corresponding component, and duplication description is abbreviate | omitted.

  The low-quality waste heat recovery system according to the present embodiment heats the regenerator 4 using a part of the waste heat gas flowing through the low-quality waste heat gas route system 1.

  The heat required for the regenerator 4 requires 300 kW per 1 mol / s DME as shown in FIG.

  In the present embodiment, such technical matters are taken into consideration, and a heating medium heater 12 is provided between the evaporator 2 and the preheater 11 of the low-quality waste heat gas route system 1, and the waste heat gas is supplied to the heat source here. The heat medium is heated as follows, and the heated heat medium is circulated in the regenerator 4 provided between the carbon monoxide converter 6 and the carbon dioxide absorber 8 that branches the reformer 2 from the hydrogen purification system 2a. After supplying through the system 12a and producing high purity carbon dioxide, the heat medium is returned to the heat medium heater 12 and circulated.

  In this case, the regenerator 4 can cover 1/6 of the required amount of heat of 300 kW.

  Note that as the heat medium circulating between the regenerator 4 and the heat medium heater 12 via the heat medium circulation system 12a, for example, alkyl biphenyl, silicon oil, or the like is used.

Further, the hydrogen purification system 2 a is provided with a carbon dioxide absorbent circulation system 13 for circulating, for example, liquid potassium carbonate between the regenerator 4 and the carbon dioxide absorber 8. Is circulated to absorb carbon dioxide CO ₂ contained in the reformed gas.

  Thus, in this embodiment, the heat medium heater 12 is provided between the evaporator 3 and the preheater 11 of the low-quality waste heat gas path system 1, and the heat medium heated here is supplied to the regenerator 4. Since the configuration is made to cover 1/6 of the amount of heat required by the regenerator 4, the energy of the waste heat gas can be effectively recovered.

  FIG. 6 is a schematic system diagram showing a fourth embodiment of the low-quality waste heat recovery system according to the present invention.

  In addition, the same code | symbol is attached | subjected to the component same as the component shown by 1st Embodiment, or a corresponding component, and duplication description is abbreviate | omitted.

In general, in a carbon dioxide absorber used in the carbon dioxide treatment field, only carbon dioxide CO ₂ can be absorbed, and carbon monoxide CO is contained in the crude purified hydrogen gas. Although converted carbon monoxide CO to carbon dioxide (CO _2), only the carbon monoxide shift converter at present can not convert carbon dioxide CO ₂ in only about 2%.

For example, in a fuel cell having a low operating temperature such as a polymer electrolyte fuel cell, the allowable value of the concentration of carbon monoxide contained in the fuel gas is 10 ppm, and the cooler 7 and the carbon dioxide absorber 8 of the hydrogen purification system 2a Is provided with a carbon monoxide selective oxidizer 14, air is added to the carbon monoxide selective oxidizer 14, and carbon monoxide CO supplied from the carbon monoxide converter 6 through the cooler 7 is converted into carbon dioxide CO. _The carbon dioxide CO ₂ thus converted is absorbed by the carbon dioxide absorber 8, and the remaining hydrogen-rich reformed gas is reduced to 10 ppm or less of carbon monoxide and recovered by the hydrogen crude purification and recovery device 15. is there.

Thus, in this embodiment, the carbon monoxide selective oxidizer 14 is provided between the cooler 7 and the carbon dioxide absorber 8 of the hydrogen purification system 2a, and the carbon monoxide selective oxidizer 14 uses the carbon monoxide CO. Is selectively oxidized and converted to carbon dioxide CO ₂ , so that a relatively high-quality hydrogen-rich reformed gas having a concentration of carbon monoxide CO of 10 ppm or less can be purified, and a fuel cell with a low operating temperature. Can also be served directly.

  FIG. 7 is a schematic system diagram showing a fifth embodiment of the low-quality waste heat recovery system according to the present invention.

  In addition, the same code | symbol is attached | subjected to the component same as the component shown by 1st Embodiment, or a corresponding component, and duplication description is abbreviate | omitted.

  The low-quality waste heat recovery system according to this embodiment is provided with a pressure swing adsorption device 16 and a high-purity hydrogen gas recovery device 17 on the downstream side of the carbon dioxide absorber 8 of the hydrogen purification system 2a, and the pressure swing adsorption device 16 An off-gas system 19 is provided in which an impure gas having a combustible component captured in step 1 is supplied to the burner 18 of the reformer 2 to generate combustion gas.

  The pressure swing adsorption device 16 pressurizes the inside of the device to, for example, about 1 atm, passes only hydrogen gas out of the reformed gas supplied from the carbon dioxide absorber 8, and captures the remaining impure gas. When collecting the trapped impure gas, the inside of the apparatus can be depressurized and removed.

  Then, the pressure swing adsorption device 16 causes the high-purity hydrogen gas recovery unit 17 to recover hydrogen gas having a purity of 99.99% or more that passes through the pressure swing adsorption device 16, and the trapped impure gas having combustible components through the off-gas system 19. It is supplied to the burner 18 and combustion gas is given to the reformer 2.

  Thus, in this embodiment, the pressure swing adsorption device 16 is provided on the downstream side of the carbon dioxide absorber 8 of the hydrogen purification system 2a, and the hydrogen gas is passed through the pressure swing adsorption device 16 to increase the purity. Since the impure gas having a combustible component is supplied as fuel gas to the burner 18 of the reformer 2 through the off-gas system 19, the energy is effectively utilized without waste and supplied to the combustion gas of the reformer. Energy consumption can be saved accordingly.

  In this embodiment, the pressure swing adsorption device 16 is provided on the downstream side of the carbon dioxide absorber 8. However, the present invention is not limited to this example. For example, as shown in FIG. The first and second pressure temperature swing adsorption devices 20a and 20b may be provided between the carbon monoxide transformer 6 and the carbon dioxide absorber 8 of the hydrogen purification system 2a.

  These first and second pressure-temperature swing adsorption devices 20a and 20b, like the above-described pressure swing adsorption device 16, allow hydrogen gas to pass through and trap impure gas when the pressure or temperature in the device is increased, When removing the trapped impure gas, it has a function that can be removed by reducing the pressure or reducing the temperature in the apparatus.

  Therefore, this embodiment can also supply impure gas having a combustible component captured by the first pressure temperature swing adsorption device 20a to the burner 18 of the reformer 2 via the off-gas system 19, so that energy can be effectively used without waste. It can be used and energy consumption can be saved.

1 is a schematic system diagram showing a first embodiment of a low-quality waste heat recovery system according to the present invention. The heat adjustment figure which shows the amount of heat recovery of the low-quality waste heat recovery system which concerns on this invention. The figure which shows the design essential point of the low-quality waste heat recovery system which concerns on this invention. The schematic system diagram which shows 2nd Embodiment of the low-quality waste heat recovery system which concerns on this invention. The schematic system diagram which shows 3rd Embodiment of the low-quality waste heat recovery system which concerns on this invention. The schematic system diagram which shows 4th Embodiment of the low-quality waste heat recovery system which concerns on this invention. The schematic system diagram which shows 5th Embodiment of the low-quality waste heat recovery system which concerns on this invention. The schematic system diagram which shows 6th Embodiment of the low-quality waste heat recovery system which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Low quality waste heat gas route system 2 Reformer 2a Hydrogen purification system 3 Evaporator 4 Regenerator 5 DME (dimethyl ether) vaporizer 6 Carbon monoxide converter 7 Cooler 8 Carbon dioxide absorber 9 Hydrogen crude refiner 10 Purity carbon dioxide collector 11 Preheater 12 Heat medium heater 12a Heat medium circulation system 13 Carbon dioxide absorbent circulation system 14 Carbon monoxide selective oxidizer 15 Hydrogen crude purification and recovery device 16 Pressure swing adsorption device 17 High purity hydrogen gas recovery device 18 Burner 19 Off-gas system 20a First pressure temperature swing adsorption device 20b Second pressure temperature swing adsorption device

Claims (7)

In a low-quality waste heat recovery system that uses waste heat gas as a heat source and reforms dimethyl ether to produce hydrogen gas,
A low-quality waste heat gas route system for passing waste heat gas,
A hydrogen purification system that purifies hydrogen gas from the reformed gas that is branched from this low-quality waste heat gas route system and reformed dimethyl ether ,
The hydrogen purification system includes, in order along the flow of the reformed gas, a carbon monoxide converter, a first pressure temperature swing adsorption device, an off-gas system, a carbon dioxide absorber, a second pressure temperature swing adsorption device, and a high purity. A low-quality waste heat recovery system equipped with a hydrogen gas recovery unit . The low-quality waste heat gas route system includes a reformer, an evaporator, a regenerator, and a dimethyl ether vaporizer in order from the highest waste heat gas temperature to the lowest. Low-quality waste heat recovery system. The carbon dioxide absorber provided on the hydrogen purification system, comprising the carbon dioxide absorbent circulation system for circulating a carbon dioxide absorber between the regenerator provided in the low-quality waste heat gas route system The low-quality waste heat recovery system according to claim 2 . The low-quality waste heat recovery system according to claim 2 or 3 , wherein the regenerator includes a high-purity carbon dioxide recovery unit. In a low-quality waste heat recovery system that uses waste heat gas as a heat source and reforms dimethyl ether to produce hydrogen gas,
A low-quality waste heat gas route system for passing waste heat gas,
A hydrogen purification system that purifies hydrogen gas from the reformed gas that is branched from this low-quality waste heat gas route system and reformed dimethyl ether,
The hydrogen purification system includes, in order along the flow of the reformed gas, a carbon monoxide converter, a regenerator, a carbon dioxide absorber, and a hydrogen crude purification and recovery device.
Heating medium heater provided in the low-quality waste heat gas route system, low quality waste heat, comprising the heating medium circulation system that circulates the heating medium between the regenerator provided in the hydrogen purification system Collection system. The low-quality waste heat gas route system includes a reformer, an evaporator, the heating medium heater, a preheater, and a dimethyl ether vaporizer in order from the highest waste heat gas temperature to the lowest. The low-quality waste heat recovery system according to claim 5 . The low-quality waste heat recovery system according to claim 5 or 6 , wherein the regenerator includes a high-purity carbon dioxide recovery unit.

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