JPS59161480A - Dry distillation of oil shale - Google Patents

Abstract

PURPOSE:After oil shales on the moving grates are passed through the dry distillation zone, coal is combined, then they are burnt in the zone contacting with a gas stream containig oxygen to recover the combustion heat as increase in gas sensitive heat to effect high-efficiency dry distillation of the titled substance with no formation of powdery substances. CONSTITUTION:Crushed oil shales F are placed on the moving grates 1 to form an oil shale layer 2 and the layer is sent to the first zone W where dry distillation is effected, as the grate moves and they are exposed to a hot gas stream. Then, the oil shale is moved to the carbon-recovering zone X and crushed coal is feed from the silo SS on the left end of the zone X on the oil shale layer 2 to form a layer of crushed coal 6. These layers are exposed to a gas stream containing oxygen to burn both of the crushed coal and organic carbon remaining in oil shales and the heat of combustion is recovered as increase in the sensitive heat of the gas passing on these layers. Thus, oil shale is dry distilled to give the product gas PG and the oil O.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for carbonizing oil shale, and more specifically, there is a moving grid, fixed wind boxes are provided above and below the moving grid, and a space between the wind box and the moving grid is provided. This invention relates to a method of carbonizing oil shale using a device (hereinafter referred to as a moving grid type device) that is water-sealed and has a structure that prevents the gas inside the wind box from leaking outside.

The carbonization method for oil shale using a moving grating device called circular grate, straight grate, etc. is widely known as the method of burning and cooling VC ore using a carving device. The basic method is to heat or cool the solid particles by flowing a gas at approximately 11 orthogonal angles through a bed of solid particles loaded on the grid and moving almost horizontally with the moving grid. In the oil shale carbonization method using this moving grid type device, the oil shale to be carbonized as described above is loaded on the moving grid,
Since the oil shale itself moves in a fixed layer during the carbonization treatment, it has the characteristic that it is difficult to powder during the treatment process. As is well known, when oil shale is subjected to carbonization treatment, not only do many cracks occur in the oil shale, but it also tends to be brittle and easily fractured by the slightest impact to produce powder. For this purpose, for example, a device (hereinafter referred to as a device) for forming a moving layer of oil shale crushed material in a container in which oil shale crushed material is supplied from near the top and taken out from near the bottom and causing a gas body to flow through the moving layer (hereinafter referred to as "moving layer") When oil shale is carbonized using a dry distillation device (referred to as a type device), not only the oil shoe 11 layer moves, but also a large amount of oil shale particles are generated due to impact and g-rubbing caused by contact between oil shale particles. In this way, when a large amount of oil shale powder is generated, the gas flow resistance within the oil shale layer increases, which not only increases the blowing power but also causes a biased flow of gas within the oil shale layer. Sufficient carbonization becomes impossible, and a large amount of oil shale powder is mixed into the carbonization product oil, resulting in a decrease in the quality of the carbonization product oil.

For this reason, the oil shale carbonization method using a moving grid type device, which generates very little oil shale powder during the oil shale carbonization process, is rated as a superior method.

A conventional method for carbonizing oil shale using a moving grid type device is described in US Pat. No. 3,325,395;
082645, etc., and also in Document-1 [Oil Shale Data Book (Oil 5hale Da
ta Book); -+--J-Sudenok-Tment of Commerce, National Technical Information Booths 1 BP 80-12563
6 (U, S-Department of Comm
erce, National Technical
Information Service+ PH10
-125636) ) to Circular Grate Carbonization Process, (Circular GrateRet
ortingProcess).

Based on the system diagram introduced in this document-1, an overview of the conventional method and its drawbacks will be explained.

The system diagram shown in Figure 1 is the direct heating circular-great carbonization process (C1rc) introduced in Reference-1.
ular Grate Retorting Proc
ess) and 6jl), a heating carbonization section W divided by partition walls a and b.

The oil shale layer 2 loaded on the grid 1 moves through the carbon recovery section X1 divided by the partition walls C and the GL cooling section Y1 separated by the partition walls C and d, and the second cooling section 2 divided by the partition walls d and e. As it moves, it is exposed to the gas flow supplied to each section for carbonization, carbon recovery, and cooling.

That is, in the first ffl, on the left side of the heating carbonization section W, the moving grid l is
Crushed oil shale is loaded on top to form an oil shale layer 2, and as the moving grid 1 moves, the oil shale layer first enters the heating carbonization section W, and the oil shale layer is carbonized by carbonization contained in the circulating gas. After being heated and carbonized by being exposed to a hot gas stream obtained by burning the generated gas, it is moved to the carbon recovery section X.

The oil tank layer moved to the carbon recovery section Carbonization of uncarbonized oil shale is performed. Next, the oil shale layer moves to the idle cooling section Y, where it is exposed to a circulating gas flow and cooled, and then moves to the secondary cooling section Z, where it is exposed to an air flow and cooled, and the shale layer is cooled by exposure to the air flow. After the heat is recovered, it is discharged outside the system.

The gas that has flowed out of the heating carbonization section W and the carbon recovery section A portion is taken out as a product gas, and the other portion is supplied to the first cooling section Y as a circulating gas. The gas preheated in the first cooling section Y is supplied to the heating carbonization section W by the blower 4, is preheated in the second cooling section Z, is mixed with the rush air supplied by the blower 5, and is added to the circulating gas. A portion of the carbonization product gas mixed with the contained air and contained in the circulating gas is combusted to form hot gas, which is then subjected to calothermal carbonization of oil shale.

In Figure 1, F stands for raw oil shale, D stands for waste shale, A stands for air, B stands for tanker, PC stands for compressor and cooler, PG stands for product gas, and DOW stands for carbonized oil and carbonized water. . As mentioned above, the method shown in Figure 1 has the characteristic that air is directly blown into the circulating gas stream to combust a portion of the carbonization product gas, thereby obtaining the hot gas required for carbonization of oil shale without any special equipment. On the other hand, there are disadvantages that the calorific value of the resulting product gas is extremely low and that the recovery rate by combustion of the organic carbon remaining after carbonization is low. In particular, the latter poses problems in the following points.

It is well known that the organic carbon contained in oil shale varies greatly depending on the location where oil shale is produced, even if it is produced in the same region. There were changes like this.

(74'/-?-assay (Fischer As5
ay) Analysis) Organic carbon concentration: 4.4 to 25.9% by weight (based on raw oil shale) After carbonizing these oil shale, the concentration of organic carbon remaining in the fer was measured as follows.

Residual organic carbon concentration: 1.1 to 14.7% by weight (based on raw material oil shale) When the residual ratio of organic carbon in the raw material fer is calculated from this, the residual organic carbon ratio is 25 to 82% by weight. As described above, it has been found that the proportion of organic carbon remaining in Fehr after carbonization varies, but is quite large. Therefore, burning this residual organic carbon and recovering the combustion heat is an important factor determining the thermal efficiency of the carbonization process.

However, in the conventional carbonization method as mentioned above, the oil shale after carbonization is simply exposed to an air flow and combusted. When using a type device, the particle size of sierre is large, ranging from 10 to 100 gourds, so the combustion rate is relatively slow and it is difficult to recover sufficient residual carbon by combustion.Therefore, the present inventors The present invention was achieved as a result of efforts to eliminate the above-mentioned drawbacks without sacrificing the advantages of the carbonization method using a moving grid type device.

, The gist of the process is to supply crushed coal to the top of a layer of crushed oil shale after carbonization, form a layer consisting of the oil shale and crushed coal, and then expose it to an oxygen-containing gas flow to separate the coal and oil shale. This paper proposes a carbonization method using a moving grid device that burns both residual organic carbon and recovers the heat of combustion.

Specifically, the layer of crushed oil shale loaded on the moving grid passes through the first section where it is heated and carbonized by being exposed to a hot gas flow flowing through the oil shale layer. A process for the carbonization of oil shale using a moving grate apparatus, the method comprising passing through a second section exposed to a flowing oxygen-containing gas stream, supplying crushed coal on top of the crushed oil shale that has passed through the first section. death,
After forming a layer consisting of the oil shale and crushed coal, the layer is passed through the second section, and in the second section, both the crushed coal and the organic carbon remaining in the oil shale after carbonization are removed. The present invention proposes a method for carbonizing oil shale, which is characterized by burning the oil shale and recovering the combustion heat as an increase in sensible heat of gas passing through a layer consisting of the oil shale and crushed coal.

Next, in order to clarify the embodiment of the present invention, a description will be given with reference to FIG. 2.

The system diagram shown in Figure 2 is a direct heating circular-grate carbonization process (C1rcular Grate Carbonization process).
When the present invention is applied to the torting process), the partition wall al! : Heating carbonization section W divided by b.

The oil shale layer 2 loaded on the moving grid 1 moves through the carbon recovery section It is exposed to the supplied gas stream for carbonization, carbon recovery and cooling.

That is, in FIG. 2, on the left side of the heating carbonization section W, crushed oil shale is loaded onto a moving grid L using an oil shale supply device R (not shown) to form an oil shale layer 2. 2, as the moving grid l moves, it first enters the heating carbonization section W, and after being exposed to the hot gas flow obtained by burning the carbonization product gas contained in the circulating gas and being heated and carbonized, carbon is recovered. Move to section X.

At the left end of carbon recovery section X is a silo SS for supplying crushed coal.
A layer 6 of crushed coal is formed on the top of the oil shale layer 2 where carbonization has been completed, and then exposed to an air flow to burn both the crushed coal and the organic carbon remaining in the oil shale. In this case, since general trap coal burns more easily, it becomes a ignition source and promotes the combustion of the organic carbon remaining in the oil seal.

Reference 2 [Mathematical Modeling of Modified in Syrah] It is possible to improve the recovery rate of residual organic carbon in oil shale after carbonization, and the combustion of coal itself can be realized without adding a new combustion device.
Anne, Doorbub Grand Oil Cher Retortink; Lawrence Live Emore Nashi Seal Laboratories R.E. 53119 (Math
mechanical modeling of Modi
fied In5itu and Abovegrou
nd O4l 5hale Retorting ;L
awrence Livermore Nationa
l Laboratory UCRL-53119)
According to ,:l, the combustion of organic carbon in oil shale is determined by the rate of diffusion of oxygen that diffuses through the ash layer generated by combustion, and in this case, the effective diffusion coefficient is said to be faster at higher temperatures. . Therefore, raising the temperature of the air flow using coal, which is relatively easy to ignite, increases the effective diffusion coefficient of oxygen, which has the effect of improving the combustion recovery rate of residual organic carbon. Coal distills tar when heated, so it is desirable to add it to the oil shale after passing through the carbonization zone, but coke is the product from which tar has been distilled out, and in this case, it is added to the oil shale after passing through the carbonization zone. It is also possible to add it to oil shale.

The gas that has flown out of the heating carbonization zone W is separated from the carbonization product oil and carbonization product water that flow out together with the gas in a gas-liquid separator S, and then is sucked into the blower 3 and a portion is taken as product gas. The other part is first supplied to the heat exchanger H as a circulating gas. In the heat exchanger H, the circulating gas is heated by exchanging heat with the hot gas that has flowed out of the carbon recovery section X, and is then circulated to the heating carbonization section W again. The gas flowing out of the carbon recovery section is discharged to the outside of the υ system by the blower 4. Heating section W
A part of the circulating gas is combusted in burner B installed at the gas side inlet of the reactor and turned into hot gas, which is then used for carbonization. In addition, air is supplied to the cooling section Y, and after being heated up by the sensible heat of the waste siere, part of it is transferred to lye/g by the blower 5, and the part is sent to the carbon recovery section X, and part of it is sent to the line h. The fuel is supplied to the heating carbonization section W, and is used for combustion of coal and residual carbon, and for combustion of circulating gas, respectively. The remainder will be discharged outside the company.

On the other hand, the produced oil and water separated by the gas-liquid separator S are separated into oil and water by the oil-water separator E, and then the oil and water are each discharged out of the system. In Figure 2, F represents raw oil shale, D represents waste shale, FC represents coal, A represents air,
A) l indicates hot air discharged outside the system, F indicates exhaust gas flowing out of the organic carbon recovery section, PG indicates product gas, 0 indicates carbonized oil, and W indicates carbonized water.

Effectively using the combustion heat of the organic carbon remaining in the coal and oil shale in carbon recovery section X to obtain hot gas for carbonization as in this embodiment example can be said to be an excellent method for improving thermal efficiency. .

Next, the effects of the present invention will be explained using examples.

Embodiment According to the embodiment shown in FIG. 2, heated air at 500° C. is supplied through line H to the oil shale layer loaded on the grid at a superficial velocity I N
The temperature of the gas flowing out of the carbon recovery section X was measured and found to be 745°C. Also, cooling section Y
The organic carbon concentration remaining in the waste shale discharged through was 2.5% by weight.

Comparative Example In the same embodiment as the example, the supply of crushed coal was stopped at the inlet of the carbon recovery section X, and the other conditions were the same as in the example, and the temperature of the gas flowing out of the carbon recovery section
It died at 0℃. Further, the concentration of organic carbon remaining in the waste shale discharged through the cooling section Y was 4.1% by weight.

From the examples and comparative examples, it can be seen that by supplying crushed coal to the carbon recovery section, the effect of burning both the coal and the residual organic carbon in the oil fail can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional oil shale carbonization method using a moving grid type device, and FIG. 2 is an explanatory diagram showing an embodiment of the present invention. engineering

Claims (1)

[Claims] The layer of oil shale debris loaded on the moving grid is
passing through a first section exposed to a hot gas stream flowing through the oil shale layer and subjected to thermal carbonization, and then passing through a second section exposed to an oxygen-containing gas stream flowing through the oil shale layer. In a method for carbonizing oil shale using a moving lattice-type device, a crushed coal is supplied to the upper part of a layer of crushed oil shale that has passed through a first section, and a layer consisting of the crushed oil shale and coal is formed. By passing through the second section, both the crushed coal and the organic carbon remaining in the oil shale after carbonization are combusted in the second section, and the combustion heat is transferred to the oil shale and the crushed coal. A method for carbonizing oil shale, which is characterized by recovering the increased sensible heat of gas passing through the layer.