JP2008174583A - Method for hydrothermal cracking of coal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve oil yield when a plurality of kinds of coal are subjected to hydrothermal cracking. <P>SOLUTION: A method for hydrothermal cracking of the coal comprises using a reactor of the upper and the lower two-chambers and two-stages and charging oxygen or the oxygen and steam and the coal and producing a gasification gas by partial oxidation in the lower stage and charging the coal and hydrogen into the produced gasification gas and producing a gas, an oil and char by hydrothermal cracking in the upper stage. The method is characterized in that the coal with a lower coalification degree than that of the coal charged into the lower stage is used as the coal charged into the upper stage. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing gas, oil, and char by rapidly gasifying and hydrothermally decomposing coal in a gas flow layer.

  To date, several coal pyrolysis processes have been proposed in which coal is pyrolyzed at high temperatures to produce fuel gas containing hydrocarbon gas such as methane and oil such as benzene, toluene and xylene (BTX). Has been.

  In Patent Document 1, coal is blown into a high-temperature gas generated by gasification of coal and carbonaceous raw material with oxygen, and rapid heating / pyrolysis reaction of coal is performed in an air flow layer, and in particular, BTX is obtained in a high yield. It is possible to reduce the initial cost of the equipment, and there is shown a high thermal efficiency coal pyrolysis method that does not require heat supply.

  Further, in Patent Document 2, coal and hydrogen are blown into a high-temperature gas generated by gasification of coal and carbonaceous raw material with oxygen, and rapid heating / hydrocracking reaction of coal is performed in an airflow layer, A coal hydrothermal pyrolysis method that can obtain a fuel gas such as methane in a high yield is shown.

JP-A-5-295371 JP 2004-217868 A

  In the processes proposed in Patent Documents 1 and 2, it is possible to change the properties of the product to some extent by changing the raw materials to be pyrolyzed and the operating conditions. However, when actually operating a large-scale plant, from the security point of view of securing diverse raw material suppliers, and the cost of always purchasing and using inexpensive raw materials at that time, Often, different types of coal are used at the same time, and there is no particular mention of how to use the coal in such cases.

  The object of the present invention is to increase the oil yield more efficiently when oil is mainly produced by hydropyrolysis using a plurality of different types of coal.

In order to solve this problem, the gist of the present invention is as follows.
(1) In the lower stage, oxygen or oxygen and water vapor and coal are introduced to generate gasified gas by partial oxidation. In the upper stage, hydrogen and hydrogen are introduced into the generated gasified gas. A method for hydropyrolysis of coal using a two-stage reactor with two upper and lower chambers to generate gas, oil, and char by pyrolysis, wherein the coal to be fed into the upper stage is replaced with the coal to be fed into the lower stage Also, a method for hydrocracking coal, which uses a low degree of coalification.
(2) Coal of a plurality of coal types, respectively, or mixed and stored in at least two types of coal groups, and after measuring the degree of coalification of each of the stored coal groups, each coal group The two types of coal groups are selected from the above, and among the selected coal groups, the one with the higher degree of coalification is introduced into the lower stage, and the lower one is introduced into the upper stage for use. The method for hydrocracking coal as described.

  According to the present invention, it is possible to increase the yield of oil obtained by hydrocracking of coal.

  When coal is gasified using oxygen as a gasifying agent, a gasified gas mainly composed of carbon monoxide, carbon dioxide, hydrogen, and water vapor is generated. The temperature of the gasification furnace is not less than its melting point because it is necessary to melt and discharge ash contained in the coal to be gasified, and is generally about 1300 to 1600 ° C. The temperature of the gas leaving the gasification furnace is also the temperature. By mixing this gasification gas with coal and hydrogen in the reforming furnace, the temperature of the coal is raised and a hydrogenation pyrolysis reaction occurs to obtain a product. This is a hydrocracking method of coal using a stage reactor.

  Moreover, by using two chambers and two stages, it is possible to completely separate the part that performs gasification of coal and the part that performs hydropyrolysis, and it is possible to freely set the operating conditions of each part. Here, the two-chamber reactor is a reactor structure in which the gas flow path is partially throttled to partially increase the flow velocity, so that coal particles or the like thrown into the upper chamber fall into the lower chamber. A reactor that can prevent reaction and set independent reaction conditions in each chamber.

  The present invention will be described in detail below. FIG. 1 is a schematic view of a hydropyrolysis apparatus used in the present invention. This apparatus is mainly composed of a reforming furnace 1, a gasification furnace 2, and a throat 3 that connects the two.

  Since the ash contained in the gasified coal 9 becomes a molten slag 15 due to a high temperature of about 1500 ° C., a slag tap 6 and a water tank 8 for collecting the slag 15 are provided so as to be discharged from the lower part of the gasification furnace 2. It is preferable.

In the gasification furnace 2, one or a plurality of gasification burners 5 for introducing the gasified coal 9 together with the oxygen 12 or the oxygen 12 and the water vapor 13 are installed. In the gasification furnace 2, in order to convert as much carbon and hydrogen contained in the gasification coal 9 as possible into CO and H ₂ , the gasification coal 9, oxygen 12, and water vapor 13 are quickly mixed to form the gasification coal 9. It is necessary to react with oxygen 12 or water vapor 13 before the generated volatile matter is sooted. For this purpose, the gasified coal 9, oxygen 12 and water vapor 13 into the gasification furnace 2 are blown by the gasification burner 5 and mixed rapidly. The gasification gas 14 generated in the gasification furnace 2 is sent to the reforming furnace 1 through the throat 3. In the reforming furnace 1, the reformed coal 10 and the hydrogen 11 are input to cause a hydrogenation pyrolysis reaction. In hydrocracking of coal, it is possible to stabilize the volatile matter generated by hydrogen compared to the case of simply performing pyrolysis, and it is possible to reduce the weight by preventing polymerization of the volatile matter. This hydropyrolysis reaction produces gas, solid char, and oil from coal.

  Gas can be used as fuel or chemical raw material, char can be used as solid fuel, and oil can be used as chemical raw material or fuel. Here, oil refers to oil that has been lightened by hydrogenation compared to tar obtained by thermal decomposition, and its value is high.

  When the oil yield by hydrogenation reaction was investigated in various coals, it was found that the use of coal with a low degree of coalification yielded more oil than that with a high degree of coalification. This is because, in so-called young coal with a lot of oxygen in the coal, oxygen atoms enter the coal structure, and the oxygen bonds are weaker than the bonds between carbons, so the coal structure is easily decomposed and relatively light components are present. It seems to increase.

Since most of the raw material coal uses a plurality of types of coal, it is necessary to operate within the range of purchased coal. Therefore, when several kinds of coal are used in this hydropyrolysis process, those having a low degree of coalification are used as the reformed coal 10, and the remaining coal having a high degree of coalification is used as gasified coal 9. By using it, it becomes possible to increase the oil obtained. In the gasification furnace 2, the gasified coal 9 is converted into a gas containing almost all CO and H ₂ as main components, so that no oil is generated, and the degree of coalization of the gasified coal 9 does not affect the amount of oil generated.

  The degree of coalification refers to the degree of progress of the process of transforming the source plant of coal into coal. Although there are several definitions of the degree of coalification, in this patent, it is expressed by the molar ratio (C / O) of oxygen and carbon contained in coal.

  FIG. 2 shows a general call band. The horizontal axis represents the ratio of oxygen to carbon contained in coal (O / C). Those with a high ratio have a low degree of coalification, and those with a low ratio have a high degree of coalification. The same can be said for H / C, but it is preferable to judge the degree of coalification by O / C where the difference is significant in coal with a low degree of coalification.

  The difference in the degree of coalification is caused by the environment in which the coal is produced, and varies depending on the coal type. The measurement of C / O can be calculated from the elemental analysis results of each coal, and can be obtained by using a sample sampled from a coal hopper after mixing as an analysis sample.

  Coal with low coalification and low C / O is used as coal to be introduced into the reforming furnace 1, but when there is only a small amount of coal with low coalification, Even if it is put into the reforming furnace 1, the production unit of oil, gas, etc. produced from each coal does not change, so that the mixed use of coal is possible.

  As a mixing method, there are a method of simultaneously supplying coal stored in separate hoppers to a coal pulverizer, a method of supplying several types of pulverized coal from one hopper to one hopper, and then transporting them to a reactor. is there. The same effect can be obtained by storing the coal as a hopper for supplying coal in at least two types of coal groups and using the one with the higher degree of coalification in the gasification furnace 2 and the one with the lower degree of coalification in the reforming furnace 1. Can be obtained.

  The pressure inside the reforming furnace 1 and the partial oxidation unit 2 is preferably 1.0 MPaG or more in order to promote the production of oil by lightening the volatile matter produced from coal.

  Moreover, in view of the recent promotion of resource recycling, even if the present invention is carried out by adding a small amount (about 10%) of a carbonaceous raw material obtained by pulverizing biomass, waste plastic, etc. in addition to coal, The rate can be improved and is applicable.

(Example)
An example in which a hydropyrolysis operation is performed using the apparatus shown in FIG. 1 and using the same two types of coal shown in Table 1 is shown below.

  When operating the reforming part temperature at 800 ° C., if the coal gasification amount in the gasification furnace is 500 kg / h, about 300 kg / h coal can be input in the reforming furnace. B coal with a large degree of O / C and low degree of coalification is used in the reforming furnace, and the remaining ratio of B coal and A In the sense of mixing charcoal, two types of coal were mixed and used so that A coal: B charcoal = 4: 1.

As a result, in the gasifier, 500 kg / h of coal, 315 Nm ³ / h of oxygen and 50 kg / h of steam are charged, and the operation is performed at a pressure of 2.5 MPaG and a temperature of 1550 ° C., and the amount of generated gas is about 1140 Nm ³ / h. It was. In the reforming section, a coal amount of 333 kg / h and hydrogen of 190 Nm ³ / h are charged to obtain a reforming furnace temperature of 800 ° C. As a result, gas 1530 Nm ³ / h, char 99 kg / h, and oil 53 kg / h can be obtained. It was.
(Comparative Example 1)
Using the same equipment as in the example, two types of the same amount of coal were thoroughly mixed and charged into a gasification furnace and a reforming furnace.

As a result, in the gasifier, 500 kg / h of coal, 315 Nm ³ / h of oxygen and 50 kg / h of steam are charged, and the operation is performed at a pressure of 2.5 MPaG and a temperature of 1550 ° C., and the gas generation amount is about 1150 Nm ³ / h. It was. In the reforming furnace, hydrogen was charged at 190 Nm ³ / h, and coal was charged at 321 kg / h so that the temperature in the reforming furnace became 800 ° C. As a result, gas 1560 Nm ³ / h, char 111 kg / h, and oil 44 kg / h were obtained.
(Comparative Example 2)
Using the same equipment as in the example, only coal type A was charged into the gasifier and reformer.

As a result, in the gasifier, 500 kg / h of coal, 321 Nm ³ / h of oxygen and 50 kg / h of steam are charged, and operation is performed at a pressure of 2.5 MPaG and a temperature of 1550 ° C., and the amount of gas generated is about 1160 Nm ³ / h. It was. In the reforming furnace, hydrogen was charged at 190 Nm ³ / h, and coal was charged at 317 kg / h so that the temperature in the reforming furnace became 800 ° C. As a result, gas 1580 Nm ³ / h, char 116 kg / h, and oil 38 kg / h were obtained.

  The results of Examples and Comparative Examples are summarized in Table 2. Compared with Comparative Example 1, in the example, the gas generation amount is not significantly changed, and the oil yield is increased by about 19%. Further, in the example, the gas generation amount decreased by about 3% as compared with Comparative Example 2, but the oil yield increased by about 40%.

It is the schematic of the partial hydrogenation pyrolysis apparatus of coal based on this invention. It is the figure which showed the general call band.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reforming furnace 2 Gasification furnace 3 Throat 4 Reforming coal injection nozzle 5 Gasification burner 6 Slag tap 7 Reforming furnace exit 8 Water tank 9 Gasification coal 10 Reforming coal 11 Hydrogen 12 Oxygen 13 Steam 14 Gasification gas 15 Slag 16 Product gas, char, oil

Claims (2)

  In the lower stage, oxygen or oxygen and water vapor and coal are added to produce gasified gas by partial oxidation. In the upper stage, coal and hydrogen are added to the generated gasified gas and hydrogenated pyrolysis is performed. A method for hydropyrolysis of coal using a two-stage two-stage reactor that generates gas, oil, and char, wherein the coal charged into the upper stage is more coal than the coal charged into the lower stage. A method for hydropyrolysis of coal, characterized by using a low degree of conversion.   Coal of a plurality of coal types, respectively, or mixed and stored in at least two types of coal groups, and after measuring the degree of coalification of each of the stored coal groups, two types from each coal group 2. The coal according to claim 1, wherein a coal group having a higher degree of coalification is put into the lower stage and a lower one is put into the upper stage for use. Hydrocracking method of

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