JP7089809B2 - Multi-stage hydrogen generation method - Google Patents

Description

The present invention relates to a multi-stage hydrogen generator.

There is integrated coal gasification combined cycle thermal power generation as a highly efficient power generation method for efficiently gasifying coal (see [Non-Patent Document 1]).

The demand for hydrogen is increasing. Fuel for internal combustion engines, raw materials for chemicals, power generation, iron making, etc. However, the manufacturing method is mainly high temperature decomposition of methane gas and electrolysis of water, and the cost is high. Since methane gas is a fossil fuel, it becomes a source of carbon dioxide, and its global warming effect is 25 times that of carbon dioxide (see [Non-Patent Document 4]). That is, methane is a greenhouse gas. Therefore, high-temperature steam decomposition of coal and biomass is also being studied. However, there are many types of gas generated, which requires an additional carbon dioxide conversion process. In addition, even a small amount of sulfur compounds and nitrogen compounds contained in coal and biomass becomes sulfur oxides and nitrogen oxides by gasification, so a device for removing them is required. The separation process is complicated and costly. In the present invention, the amount of processing is significantly reduced.

[Patent Document 1] describes a hydrogen production method and a system.
However, in the method of [Patent Document 1], after steam gasification of low-grade coal or biomass, the gas is cooled and then carbon monoxide is converted into carbon dioxide by steam using a catalyst. Many steps are required to produce hydrogen. In addition, since oxygen obtained by deeply cooling and separating air is used in order to raise the gasification temperature to 1000 ° C. or higher, the cost increases. In addition, a device for removing sulfur and nitrogen oxides contained in coal and biomass is not described. It is expected that the unit price of hydrogen will not decrease even if low-grade coal is used. However, the recent technological status of hydrogen production and carbon dioxide treatment has been thoroughly investigated. It also details how to separate carbon dioxide and hydrogen. Depending on the use of the water gas obtained in the present invention, it may be incorporated into an apparatus when carbon dioxide and hydrogen need to be separated.

[Non-Patent Document 1] describes an integrated coal gasification combined cycle (IGCC).
However, in the method of [Non-Patent Document 1], even if a jet gasification furnace having good performance is used, complicated post-treatment is required for gasification in one stage. However, although the gas leaving the gasifier is supplied to the gas turbine generator through the desulfurization device, the nitrogen oxide removal device that should be contained in the coal is not written. Moreover, since the gas turbine generator burns with air at 1000 ° C or higher, nitrogen oxides should have been generated, but the removal device is not written. I'm wondering if it's omitted.

[Non-Patent Document 2] describes the construction of a non-engine power generation and regional utilization system by generating water gas from charcoal made from thinned wood.
However, in the method of [Non-Patent Document 2], after the thinned wood is charcoalized, it is transferred to another device for heating and water gas generation in one stage, so that CO generation is unavoidable. Therefore, a reaction device for CO2 conversion is also required. Also, when making charcoal, the heat and flammable gas that is normally heated are released into the atmosphere, so tens of percent of the energy possessed by the thinned wood is lost. With the present invention, there is little loss and most of it can be used.

Report of the Power Supply Business Headquarters "Non-Patent Document 3" In the research of hydrogen production technology from unused resources using high temperature steam, biomass etc. are gasified in one stage, so an additional device to convert CO to CO2 is required. It has become. Fuels such as LPG are used to generate high-temperature steam of 1000 ° C or higher, and if hydrogen is produced from wood chips and waste plastic, only startups can be used, and if part of the decomposition gas is used, carbon dioxide can be used. It will suppress the occurrence.

In any of the above cases, since the raw material is gasified in one stage, some devices such as desulfurization and denitration are required by converting CO into CO2 before using the gas.

There is no limit to the use of hydrogen. Fuel for internal combustion engines, raw materials for chemicals, power generation, iron making, etc. The cost of electrolyzing water and decomposing methane gas is high, which is a social problem. If coal or oil is used, carbon dioxide will be emitted, which is a global problem. If you plant trees using biomass (mainly trees), you will not emit carbon dioxide.

Further describes the thermal decomposition of coal, the reaction with steam (that is, the water gasification reaction), and the chemical reaction of the jet gasification method and the in-furnace gasification gasification method.

In (1994), research on catalysts that react carbon dioxide and hydrogen has been reported. The possibility of industrialization in the bench plant was confirmed in 1998. And in 2008, it was confirmed by another company. However, there are no reports of industrialization until 2021.

2017 Natural Gas Chemistry, Petrochemicals, Coal Chemistry A report summarizing recent topics on Japanese petrochemicals, their surrounding natural gas chemistry in the United States and the Middle East, and modern coal chemistry in China.
But in 2018, a survey on chemical manufacturing using CO2 as a raw material However, the cost of hydrogen is high and the price of methanol synthesis cannot be reduced.

Therefore, it is highly possible that methanol synthesis from carbon dioxide is difficult to industrialize.
Also, even if you use cheap coal
As stated in the above, since coal contains nitrogen compounds, a nitrogen oxide removing device is indispensable.

Patent Publication No. 1011007493

https://www.mhi.com/jp/products/energy/integrated_coal_gasfication_combined_cycle.html Integrated Gasification Combined Cycle (IGCC) Mitsubishi Heavy Industries Group oene.co.jp/wpcontent/themes/standard_black_cmspro/img/woodbiomass_reportwww.emssy_03_1.pdf Construction of non-engine power generation and regional utilization system using charcoal water gas made from thinned wood Fuji Electric Engineering & Construction Co., Ltd. https://www.energia.co.jp/eneso/tech/review/no14/pdf/14-p16-19.pdf Research on hydrogen production technology using raw material gas from unused resources using high temperature steam https://denki.k-server.info/methane/ Electricity and environmental information Methane is a greenhouse gas and a compound that is also a natural gas resource. https://www.jstage.jst.go.jp/article/jie1922/58/2/58_2_141/_pdf Coal Chemistry Special Feature Basics of Coal Gasification Reaction ―1978.11.29 Acceptance ― Waseda Daigaku Morita Yoshiro https://www.jstage.jst.go.jp/article/jie1992/74/3/74_3_137/_pdf/-char/en Evaluation of carbon dioxide methanol conversion technology by catalytic hydrogenation reaction (keyword carbon dioxide, catalytic hydrogen) Chemical reaction, methanol synthesis, copper monozinc oxide catalyst, complex catalyst) Seiichi Oyama, Central Research Institute of Electric Power Industry http://www.mhi.co.jp/technology/review/pdf/356/356384.pdf Development of methanol synthesis process from carbon dioxide and hydrogen Mitsubishi Heavy Industries Technical Report 1998 https://www.toray-research.co.jp/technical-info/trcnews/pdf/201806-04.pdf Survey on chemical manufacturing using CO2 as a raw material https://arc.asahi-kasei.co.jp/report/arc_report/pdf/rs-1011.pdf Natural gas chemistry, petrochemicals, coal chemistry Japan's petrochemicals and the surrounding US and Middle East natural gas chemistry , A summary of recent topics on modern coal chemistry in China. It also introduces the attractiveness and challenges of natural gas and natural gas chemistry, which are becoming increasingly important. March 2017 Senior Researcher Isaburo Fukawa https://www.jstage.jst.go.jp/article/jie1992/71/8/71_8_766/_pd Effect of fuel ratio on the release behavior of coal nitrogen content-1992.2.18 Acceptance-Nakoya University Chen Isamu, Hitoshi Matsuda, Masanobu Kamiya

Gasification by steam of biomass and coal has been studied and partly put into practical use, but it is necessary to use a number of devices to produce high-purity hydrogen. Since we are particular about continuous operation and gasify in one stage to generate various kinds of compounds, we need a number of devices for gas purification and high purification of hydrogen. Furthermore, in the conventional continuous gasification method, when an abnormality such as "abnormal reaction, pipe clogging, abnormal heating, etc." occurs in a part of the device, it tends to be difficult to control stable operation. In the worst case, it is forced to stop operations.

In the present invention, in order to facilitate the purification of hydrogen, the water gasification reaction is carried out after carbonization of coal or biomass. Moreover, by using a plurality of palindromic reactors, a certain amount of hydrogen is continuously generated. Therefore, until hydrogen is collected, multiple devices are operated in the same device, so even if an abnormality such as "abnormal reaction, pipe clogging, abnormal heating, etc." occurs, the device that caused the abnormality should be disconnected and repaired. Therefore, it is a device and a system that facilitates stable operation. Furthermore, since the only gas components before hydrogen is purified to high purity are carbon dioxide, excess steam, and hydrogen, purification is easy. Therefore, in the present invention, it is a system in which a part of the purification process of the hydrogen system from the conventional gasification is already incorporated.

That is, the present invention provides a hydrogen generator having a plurality of devices in which a heating furnace and a carbonization / water gas furnace are combined side by side. The biomass and coal in the carbonization / water gasification furnace are heated from the heating furnaces on both sides with heat of 1000 ° C or higher for several hours or longer to separate almost 100% of the volatile matter. Then, since carbide having almost 100% of carbon component remains, high temperature steam is injected as a second step reaction to carry out an aqueous gasification reaction. If excessive steam is added, even if CO is generated, it becomes CO2 and H2 is generated. As a result, carbon dioxide and hydrogen are generated as in the reaction formula of C + 2H2O = CO2 + 2H2, and excess steam remains as H2O gas. Also, a small amount of biomass and coal ash remains.

The present invention further has the above-mentioned apparatus in which the carbonization / water gasification furnace is provided with steam blowing pipes in two or more stages above and below, and tar or the like does not remain in the apparatus even if solid combustibles (coal or biomass) are carbonized. I will provide a. Generally, when combustible solids are heated to evaporate volatile components, tar having a high boiling point often adheres to discharge parts and pipes. Therefore, high-temperature steam is press-fitted to decompose it into a low boiling point substance and gasify it. Then, all the volatile matter from biomass and coal is taken out of the carbonization / water gasification furnace.

The present invention further connects pipes so that air can be sent to a steam blowing pipe or the like. That is, when the temperature of the furnace drops too much due to the endothermic reaction when the aqueous gas is generated, air is blown to burn the charcoal and the temperature inside the furnace is raised. Then, the above-mentioned apparatus which facilitates the progress of the water gas reaction is provided.

That is, in the present invention, biomass and coal are carbonized to be substantially carbonized, and then excess steam is supplied to the same furnace to carry out an aqueous gasification reaction. Then, only CO2, H2, and surplus steam are left, and hydrogen can be easily separated. In order to significantly improve the thermal efficiency, a heating furnace and a carbonization / water gas furnace are combined in a sandwich type. Exhaust gas treatment requires only the gas obtained by burning the carbonization gas. Biomass and coal contain proteins and amino acids even in small amounts, so they contain nitrogen and sulfur chemically structurally.
.. Therefore, when burned, nitrogen oxides and sulfur oxides are always generated. Therefore, in order to prevent air pollution, the exhaust gas must be released into the atmosphere through the removal device.

During operation, the biomass is heated to near 1000 ° C, the flammable gas is separated, and the gas is burned to be the heat source of the heating furnace. It is known that water gas is generated when high temperature steam is excessively injected into fully carbonized coal or biomass.
.. If there is an excess of steam, carbon monoxide will also become carbon dioxide, and a large amount of hydrogen will be obtained. In the past, methanol was synthesized by generating a large amount of highly reactive carbon monoxide. In an era that requires more hydrogen than that, it is less necessary to generate carbon monoxide, and the water gasification reaction temperature can be lowered. That is, it is possible to generate a water gas containing a large amount of hydrogen under lower temperature conditions by only generating carbon dioxide. .. Moreover, if only hydrogen, carbon dioxide and extra steam are used, hydrogen can be easily separated, leading to cost reduction. If the carbonization / hydrogenation gasification furnace and the heating furnace are made into a sandwich type, the thermal efficiency is dramatically improved and mass production can be performed more than gasification in one stage. It can be mass-produced to the extent that it can be used for power generation and steelmaking.

Therefore, it becomes a device in which the heating parts of the toaster are connected in multiple stages. If biomass is used, it is not converted to carbon dioxide generation. A large number of trees that have been cut down in the forest are left in Japan.
Therefore, in the present invention, it is also a measure against carbon dioxide generation.
Hereinafter, examples of the apparatus of the present invention, Hitotsu, will be described with reference to the accompanying drawings.

The conceptual explanatory view of the apparatus for carrying out this invention. The conceptual explanatory drawing for showing the size of a heating furnace 101-150. A conceptual diagram showing a mechanism for pushing out ash. Conceptual diagram of carbonization / water gas furnace when mainly using logs.

Coal, biomass chips, etc. are filled from the upper part of the carbonization / water gasification furnace 201 to 250. Large trees such as logs may be inserted from the side. When the heat from the heating furnace does not generate carbonization gas, excessively press in steam. Carbonization gas is used as fuel for the heating furnace. Since the exhaust gas is hot, it can be used to generate high-temperature steam to generate electricity.

The principle of the method of the present invention will be described with reference to FIG.
Heating furnaces 101 to 150 and carbonization / water gas furnaces 201 to 250 are alternately arranged in a sandwich type. The carbonization gas collected from each carbonization / water gasification furnace is collected in a carbonization gas tank and then supplied to each heating furnace for use as combustion gas. The heating furnace supplies flammable gas from the outside only at the time of start-up, but normally it can be operated only with carbonization gas, and depending on the biomass and coal to be supplied and the operating conditions, the carbonization gas is surplus.

101-151 ~ Heating furnace 201-250 ~ Carbonized / water-based gasifier 1 Pipe for collecting exhaust gas after burning dry-retained gas in each heating furnace 2 Out Pipe for collecting dry-retained gas in each carbonized / water-based gasifier 2 Enter 2 Pipe that sends gas to the heating furnace from the tank that stores the dry distillate gas collected in the output 3 Pipe that collects the water-based gas generated in each carbonization / water-based gasification furnace 4 Combustion / water-based for the water-based gasification reaction Pipe for sending high-temperature steam to be press-fitted into the gasifier 5 Pipe for blowing air into each carbonized / aqueous gasifier ○ Open / close valve 11 Adjust the flow rate of exhaust gas after burning dry gas in each heating furnace. Almost open during operation 12 Close when carbonization gas is no longer emitted from each carbonization / water gas furnace.
13 Open when supplying steam.
14 Adjust the flow rate when supplying dry distillation gas to the heating furnace. 15 Close the carbonization / water gas furnace during dry distillation to prevent the outflow of dry distillation gas, and open it when taking out the aqueous gas after carbonization is completed.
16 Open when steam is supplied to the upper part of the carbonization / water gas furnace during carbonization. Then, high-temperature pressurized steam blows out from the hole in the pipe.
17 Open when steam is supplied to the lower part of the carbonization / water gasification furnace for the water gasification reaction. Then, high-temperature pressurized steam blows out from the hole in the pipe.
18 When the temperature of the carbonization / water gas furnace drops too low, it is opened when air is blown into the furnace to burn and heat the carbonized material.

Refractory bricks are generally used for the heating furnaces 101 to 105, but refractory steel may be used as long as it can be operated at 1000 ° C or lower. Since the carbonization / water gas furnaces 201 to 205 to operate at 1000 ° C or lower, heat-resistant steel is sufficient.

Heating furnaces 101-150-size. If the thickness is too thick from 0.20 m to 0.80 m, the heating efficiency will deteriorate. Larger widths of 3m to 20m can increase production, but it is difficult to make the temperature of the furnace uniform. And maintenance and inspection become difficult. The height is 3m to 10m. It should not be too large for the same reason as the width.

The thickness of the carbonization / water gas furnace 201-250-is 0,20 m-1.0 m, and it may be thicker, but it is better to be thinner for heat conduction during carbonization.

Coalization / water gasification furnaces 201-250-are filled with coal and biomass (mainly trees), and when water gasification is repeated several times, ash accumulates and is extruded.

When using logs for carbonization / water gas furnaces 201 to 250, the bottom of the furnace should be arranged in a grid pattern and dropped down.

Which of the above carbonization / water gas furnaces to use depends on the situation of the installation location.

In the present invention, biomass (mainly trees) can be efficiently used in addition to coal. In the present invention, since most of the carbon content is hydrogen, the amount of heat increases as compared with the combustion of only carbon content such as coke.
According to C + O2 = CO2-94,0Kcal, the heat of combustion of carbon is C + 2H2O = CO2 + 2H2 + 21,6Kcal. The heat of combustion of hydrogen is calculated from the two equations. And the right-hand side of the following equation can be added to add the right-hand side and the left-hand side of the following equation. Therefore, C + O2 + CO2 + 2H2 + 21,6Kcal = CO2-94,0Kcal + C + 2H2O The same thing on the left side and the right side is erased. The hydrogen generated is more than 20% of the heat of combustion.

In the present invention, even if cheap coal is used.
As stated in the above, since coal contains nitrogen compounds, a nitrogen removing device is indispensable. In the present invention, the burden is reduced as compared with the case where the entire amount of coal is gasified or burned, so that the industrial utility value is high. In the present invention, biomass and the like can also be used, so that it can be a trump card for zero carbon dioxide. In addition, the water gas from the carbonization / water gasification furnace is 900 ° C or higher, and the reaction temperature for methanol synthesis may be 300 ° C or lower (see [Non-Patent Document 7]). Even if steam is heated with a heat exchanger and used for power generation, a sufficient reaction temperature can be maintained. Therefore, effective use of heat is possible, and there is a high possibility that the manufacturing cost can be further reduced.

Methanol synthesis Conventionally CO + 2H2 = CH3OH
Use of carbon dioxide CO2 + 3H2 = CH3OH + H2O
Hydrogen prices have a significant impact on methanol prices as they require more hydrogen.

In the present invention, H2O is decomposed by carbon, so the only difference is whether the conditions include CO or all reactions to CO2. Since it is not necessary to separate impurities, it may be sent to the methanol synthesis step during the water gasification reaction depending on the methanol synthesis conditions. In the present invention, the required heat can be used for steam generation to generate electricity, so that methanol synthesis has a high possibility of cost reduction.

Methanol has also been used as a fuel for F1 racing and can be used as an alternative fuel to gasoline if the price goes down.

Claims (2)

The process of filling a carbonized / water gas furnace with solid combustibles, the process of drying by high-temperature heating from an adjacent heating furnace, and the large excess of high-temperature steam that has passed through the upper part of the heating furnace is blown into the obtained carbonized material. In the process of performing an water gasification reaction to convert all carbon dioxide into carbon dioxide, the combustible gas generated by dry distillation of solid combustibles is collected in a tank, and then the gas is supplied and burned to maintain the heating furnace at a high temperature. A hydrogen generation method that includes a step and uses a multi-stage hydrogen generator with high thermal efficiency in which a carbonization / water gasification furnace and a heating furnace are alternately combined in a sandwich type in the step. The multi-stage hydrogen generation method according to claim 1, wherein high-temperature steam is generated by using the heat of high-temperature exhaust gas from a heating furnace and used for power generation, and the heat of the generated high-temperature water gas is also used for power generation.

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