SK36093A3 - Method of cooling of hot, granular, substances in a fluid bed and device for its execution - Google Patents

Abstract

Process for cooling hot, granulated solid materials is realized under the pressure higher than atmospheric pressure up to 5 Mpa in a fluidised bed. The fluidised bed is located in a cooling chamber (1a) with a solids inlet (22) and in the second cooling chamber (1b) with a solids outlet (23), between which there is a separation (7), with an opening (15) interconnecting both cooling chambers (1a, 1b). In cooling beds the solid materials move mostly in vertical direction from the solids inlet (22) to the solids outlet (23). To the bottom area of both fluidised beds the fluidising gas is introduced and the heat is removed indirectly by means of cooling devices (6a, 6b) through which a cooling fluid flows. Both fluidising beds have the height 3 to 20 m and the height ration of fluidising beds to the average width of fluidising beds is 3 : 1 to 10 : 1. In both fluidising beds the pressure 0.5 to 5 Mpa is maintained. The cooling fluid flows in both devices (6a, 6b) occupying at least half of height of the fluidising bed, in co-flow or anti-flow to the vertical movement of solid materials and differences of the temperatures of solid materials between bottom and upper areas of both fluidising beds are maintained on the value at least 200 C.

Description

Qblasl techniques

The invention relates to a method for cooling hot, granular materials under a pressure of 2 to 50 bar in a fluidized bed, which is located in a solid-state cooling chamber and solids outlet, the solids moving predominantly from the solids inlet at one The fluidizing gas is fed to the lower region of the fluidized bed and the heat is dissipated indirectly by a cooling device which does not flow through the cooling fluid with which it occupies at least half the height of the fluidized bed, such as and apparatus for carrying out said method. The cooling device may be in a fluidized bed and / or may surround the fluidized bed.

BACKGROUND OF THE INVENTION

A method and apparatus of this kind, also suitable for work at elevated pressure, is known from ΕΡ-Λ-0 407 730.

It is an object of the present invention to provide a method and apparatus that is substantially reduced in terms of design and operating costs. In particular, intensive cooling of the solids and low consumption of fluidizing gas are required.

SUMMARY OF THE INVENTION

The problem is solved in the above method according to the invention in that the fluidized bed has a bed height of 2 to 20 m and a ratio of bed height to average bed width of 2: 1 to 19: 1 and a cooling flue. the solids flow from the solids inlet in the supercurrent orotherior, and the temperature difference of the solids between the lower and upper regions of the fluidized bed is at least PO ° C. in this case, the fluidized bed operating under pressure is located in a high, slender cooling chamber, which leads to low fluidization gas consumption when space is used well. Forced conduction of solids from the fluidized bed to the effluent creates a noticeable temperature profile in the fluidized bed on the basis of conditions favorable to heat dissipation. The fluid state is the same as the stationary fluidized bed.

Chillers operating under atmospheric conditions or under pressures less than 2 bar can only be operated at low bed height due to disturbing bubble coalescence. According to the process according to the invention, in which the pressure is operated at a pressure of 2 to 5 bar and preferably at least at a pressure of> bar, the bed height is 2 m and preferably at least 3 m. Therefore, the stationary fluidized bed is arranged over the smallest possible base area and the fluidization gas consumption is kept low.

The TJ of the method according to the invention is the ratio of the bed height to the average bed width of 2: 1 to 1r. _; and preferably 1: 1. The average bed width is calculated from the mean value of the largest and smallest bed width, raster on the horizontal plane through the fluidized bed, if the bed cross-section is not circular. If the cross-section of the bed varies above the height of the bed, the average width of the bed is obtained from the mean value of the existing average values of the different bed cross-sections that translate in

- 3 equal distances, for example 50 cm at spit height by fluid bed.

In the fluidized bed, the solids to be cooled, depending on the state of solids flow and solids flow, are forced upwards or downwards. At the same time, intensive mixing of solids in the vertical direction is not expected, so that the temperature profile of the cloths is adjusted above the bed height. Therefore, it is possible to adjust the cooling fluid flowing in the cooling device piping up or down in the fluidized bed of the counter current or even the consecutive co-current between the cooling fluid and the fluids. In particular, this leads to a large heat transfer from the solids to the cooling fluid when being conducted in countercurrent. The co-current is advantageous when the solids have cooled down immediately upon entering the fluidized bed or when the coolant stream which is controlled upstream has the cooling fluid evaporated.

The cooling fluid T1 may be quaaline or even a gaseous fluid or a vapor fluid. known cooling fluids which may be used are, for example, water, oils or salt melts. Further suitable are, for example, water oars or various gases (e.g. nitrogen) for heat dissipation.

Hot solids are fed at a temperature of about 300 to 1200 ° C, and typically are in the range of 400 to 600 ° C. Also, it is possible to produce in the fluidized bed formed according to the invention a temperature difference of solids between the lower and upper regions of the fluidized bed of 150 ° 0 and higher.

TT of the high fluidized bed of the present invention with smaller lead diameters, fluidization gas consumption is relatively low. Per m 3 of fluid bed volume of 5 and per hour, 30 to 7500 Nm · 1 of fluidizing gas is sufficient.

A further embodiment of the invention is that the hot solids are first pre-cooled in the upstream second cooling chamber, in the upstream fluidized bed. Also in the second cooling chamber, the solids move from the solids inlet at one end of the second cooling chamber to a predominantly vertical fluid bed to the solids outlet at the non-opposing end of the second cooling chamber. There is approximately the same pressure in the upstream fluid chamber as in the next fluidized bed. Even in the upstream fluidized bed, heat is removed by a cooling device through which the cooling fluid flows, whereby the cooling device extends over at least half the height of the upstream fluidized bed. For a fluid bed upstream, the bed height is in the range of? up to 20 m, and preferably the bed height is up to 3 m on average. The ratio of the bed height to the average width of the upstream fluidized bed is 2: 1 to 10: 1 and preferably at least 3: 1. Even in the upstream fluidized bed, the cooling fluid is led in a supercurrent or countercurrent movement of solids from the solids inlet to the solids outlet; the temperature difference between the lower and upper regions of the upstream fluidized bed is at least 80 ° C and preferably more than 200 ° 0. The solids pre-cooled in the upstream fluidized bed are passed from the outlet of the non-solids directly to the solids inflow in the next fluidized bed, where salter cooling occurs.

It is preferred that the solids move in the upstream fluidized bed between the solids inlet and the downstream solids outlet ε in the orifice fluidized bed while further cooling up to the solids outlet of the fluidized bed.

The invention includes another device for cooling hot granular solids under a pressure of 2 to 50 bar in a cooling chamber containing a fluidized bed of solids, which has a solids guide and solids outflow, comprises a cooling device for indirect solids cooling and in the lower region has a supply device for fluidizing gas. In this case, the cooling chamber is designed to accommodate a fluidized bed with a bed height? up to PO m and the bed height to average bed width ratio of 2: 1 to 10: 1.

A further development of this cooling device consists in providing, in addition to the cooling chamber (first cooling chamber), a non-downstream type of cooling chamber with a solids inlet and solids outlet, the solids outlet being connected to the solids inlet of the first cooling chamber.

BRIEF DESCRIPTION OF THE DRAWINGS The possibility of making the method and apparatus are explained with reference to the drawing. His fig. show:

Fig. 1 is a schematic representation of a longitudinal section through a first cooling device; FIG. 2 shows a longitudinal section of the second cooling device, FIG. 3 is a diagram of the consumption of Pluidation olyne; FIG. 4 shows a longitudinal section of a fluidized bed cooler.

DETAILED DESCRIPTION OF THE INVENTION

The device according to FIG. 1 shows a high, lean

- a cooling chamber 1 having an inflow? In the cooling chamber 1, a fluidized bed (not shown) of granular solids, which is fed via line 6, is in operation. The fluidized bed extends from the nozzle grate 6 to the outlet 3 ^and surrounds the duct of the cooling device 6 through which the cooling fluid is supplied for heat dissipation. The fluidizing gas is supplied via line 8 and first enters the distribution chamber 6 before it rises through the nozzle grate 5 and fluidizes the fuid bed. to which other work equipment, such as dedusting, may be attached.

The cooling chamber 1 is designed such that the fluidized bed contained therein has a bed height of 2 to 20 m, and preferably at least 3 m. The solid, granular substances to be cooled move from the solid inlet 2 under the action of a fluidizing gas, for example air, in the cooling chamber 1 upwards and leave the fluid bed through the outlet 3. By this determined movement of solids, the cooling fluid can be cooled. flowing in the cooling device 6 has led to solids in a supercurrent or countercurrent. To control the amount of solids entering the fluidized bed, a line 13 for supplying the control gas can be provided in the inlet 2. The cooling chamber 1 and the settling space 10 are closed by a pressure-resistant tank 12.

The cooling device of FIG. 2 shows a first cooling chamber 1a and a second cooling chamber 1b. Between the first cooling chamber 1a and the second cooling chamber 1b, there is a partition 7, with an opening 15 between the nozzle grate 5 and the lower edge of the partition 7. The pressure-resistant body closes the cooling chambers. This has an inlet 22 for the fabric and an outlet 23 for the solid. The leading edge 7 and the partition wall 2 are higher than the inlet 22 and the outlet 23 ♦ Fluidizing gases leave the body 16 through the outlet 11.

the hot solids which are fed through the inlet 22 first reach the second cooling chamber 1b, in which the fluidized bed is located, referred to herein as the upstream fluidized bed. The fluidizing gas for the upstream fluidized bed is supplied via line 19, reaches the distribution chamber 20 and then flows upwardly through the second cooling chamber 1b to the outlet 11. The solids move upstream of the upstream fluid bed 1b and enter through the opening 15 into the fluidized bed. the bed of the first cooling chamber 1a. The area of the opening 12 has its own supply of flue gas through a line 24 and a distribution chamber 25, which is located below the grate 2 θ by nozzles. By varying the amount of gas supplied through line 21, the amount of solids entering the orifice 19 can be affected. In this way, the solids flow can be controlled to the first cooling chamber 1a in the manner of the fluid-flow valve.

The aperture 15 serves as a solids inflow for the fluidized bed in the first cooling chamber 1a, in which the solids move upwardly in the stationary fluidized bed until they leave the cooling device via the outlet 23. ^| The luidization gas is supplied via a duct 16 and enters the fluidized bed through the distribution chamber 27 and the nozzle grate 2. Referring to FIG. 2, the first cooling chamber 1a and the second cooling chamber 1b may also be arranged in a body which is not dimensioned for a higher pressure which is located in a separate pressure body, as shown in FIG. First

for the first cooling chamber 1a and the second cooling chamber 1b, as well as for the fluidized beds therein, what has been said previously for individual beds with respect to bed height, bed height to average bed width and temperature the difference between the lower and upper regions of the fluidized bed. As can be seen, in both the upstream fluid bed and the subsequent fluidized bed, a supercurrent or countercurrent may be provided in the first cooling chamber 1a between the solids and the cooling fluid, wherein the cooling fluid is flowing through the devices 6a and 6b.

In many applications, the fluidizing gas velocities are in the range of 0? up to 0.8 m / s and can be considered approximately independent of pressure.

In the diagram of FIG. 3 is shown for a fluidizing gas velocity of 0.5 m / s and a temperature of 500 ° C, as well as for a particle size of solids in a fluid bed of 100 to 400 µm with a fluidizing gas consumption of V / v Nm- / h and m-3 of fluidized bed. measured pressure dependence p for different bed heights h / h = 1, 2,5,10 and 20 m /. For example, point A shows that a pressure of »p = 10 bar and a height of h = 1 m and v = 6500 must be used, compared with only V = about 1300 at the same pressure and bed height h = 5 m / point B /. «Comparative example

In the below-described, partially calculated comparison, the known fluidized bed cooler of FIG _. 4 is compared with the high fluidized bed cooler of FIG. 1, the fluid bed cooler of FIG. 4 has a body 30 with a solids inlet 31, a solids outlet 32, a fluidized-gas supply system 33 and is divided by three divider bodies 34 in the mode of operation, into four chambers 35, 36, 37 and 38. In all chambers 35, 36, 37 »38 there is a fluidized bed, wherein the solids move through the walls 34 from the inlet 3I through the fluidized bed passage to the outlet 22. All fluidized beds are indirectly cooled by a cooling device 39 supplied with cooling water;

In a comparative example, the horizontal cross-sectional area of each chamber of the apparatus of FIG. 4 0.88 m ² , fluidized bed according to FIG. 1 also has a horizontal cross-sectional area of 0.88 · Further data can be found in the following table:

Fig. 4 fig · 1

height of fluid bed 0.5 m 2,0 m total fluid volume bed 1.76 m ³ 1.76 m ³ surface of the cooling device 36 ; m ² 36 m ² pressure 10 bars 10 bar fixed charge substances 0 500 KRR / h 2 500 kg / h consumption cools acej vody P. 000 kp / h 8 000 kg / h snotreba fluida oly- nu 48 000 kg / h 12 000 kg / h temperature: solids to 700 ° C 700 ° 0 solids from 126 Mp 123 ° C cooling water to 30 ° C Deň: 29 ° C cooling water from 92 C 98 ° C fluidizing gas to 150 0 ° 150 ° o fluidizing gas from 146 C 123 °

The data, which is partly calculated, is based on a substance consisting of ash of coal and having a grain size in the range of 0.1 to 1 mm. The fluidizing gas is air, which is guided in all cases through the fluidized bed at a rate of 0.4 to 10.

0.7 m / sec.

The table shows that with the same fluidized bed volume, same cooling device, same cooling water consumption and the same fluidizing gas velocity for the high fluidized bed of FIG. 1, a quarter of the fluidization or olyne consumption is sufficient compared to FIG. 4, while reducing the cost of construction. In the calculations, it was not necessary to take into account the dead corners which, in experience, advantageously appear in the flat bed fluid coolers according to FIG. 4 and further impair the efficiency.

Claims (11)

PATENT CLAIMS A method for cooling hot, granular flocculants under a pressure of 2 to 50 bar in a fluidized bed, which is located in a cooling chamber and a solids inlet and solids outlet, the solids moving mostly in a vertical direction from the solids inlet at one end of the fluidized bed through the fluidized bed to drain solids at the orotilal end of the fluidized bed, the fluidizing gas being introduced into the lower region of the fluidized bed and the heat removed indirectly by a cooling device through which the cooling fluid flows at least half the height of the fluidized bed; characterized in that the fluidized bed has a bed height of 2 to PO and a bed height to average bed width of 2: 1 to 10: 1, the cooling fluid flows in a supercurrent or countercurrent to the solids movement from the solids inflow solids outflow and solids temperature difference between the lower and upper regions ou fluidised bed is at least 80 ° C. Method according to claim 1, characterized in that the fluidized bed has a bed height of at least 3 m. Λ y _z Method according to claim 1 or 2, characterized in that the ratio of the height of the fluidized bed to its average width is at least 3; 4 · A process according to claims 1 to 3, characterized uj account whether the T _{"m> Some} cooling fluid flows countercurrently to the solids moving from the inlet to the outlet solids solids. Method according to one of Claims 1 to 4, characterized in that the temperature difference of the solids between the lower and upper regions of the fluidized bed is at least 200 ° C. Method according to one of Claims 1 to 5, characterized in that the pressure in the fluidized bed is at least 5 bar. Method according to one of claims 1 to 6, characterized in that m ^; The fluidized bed is fed to 1 m < 3 > of fluidized bed volume and 300 to 7500 fluidizing gas per hour. Method according to one of claims 1 to 7, characterized in that the solids to be cooled are fed into the lower region of the fluidized bed and removed from the upper region of the fluidized bed. Method according to one of Claims 1 to S, characterized in that the hot solids are pre-cooled in the upstream second cooling chamber in a upstream fluidized bed in which the solids move predominantly vertically from the solids feed to one of the solids. at the opposite end of the second cooling chamber and from there pass directly into the fluidized bed of the first cooling chamber, with the second cooling chamber having approximately the same pressure as in the first cooling chamber, and the Cluidant gas is introduced. to the lower region of the upstream fluidized bed and the heat is dissipated indirectly by a cooling device through which the cooling fluid flows, the cooling device being located within 13 of the second cooling chamber and extends over at least half the height of the non-fluidized bed; 2 to 20 n. preferably at least 3 m, and the ratio of bed height to average width of the fluidized bed is 2: 1 to 10: 1 and preferably at least 3: 1, and the cooling fluid flows in the second cooling chamber in a supercurrent or countercurrent to solids movement from the solid inlet The temperature difference between the lower and upper regions of the upstream fluidized bed is at least 80 ° C. Method according to claim n, characterized in that the solids in the upstream fluidized bed move between the solids inlet and the solids outlet downwards and in the connected fluidized bed the solids move between the solids inlet and solids outlet upwards. . 11. The method of claim 10, wherein the amount of solids passing from the upstream fluidised bed to the unconnected fluidized bed is fluidically controlled. 12. Apparatus for cooling hot, granular solids under a pressure of 2 to 50 bar in a fluidized bed of solids arranged in a cooling chamber, which has a solids inlet, solids effluent and a non-direct cooling of solids in the lower region It is provided with fluidizing gas supply means, characterized in that the cooling chamber (1) is designed to accommodate a fluidized bed having a bed height of 2 to 20 m and a ratio of bed height to average bed width of 1 to 10: 1. 14. The tariotium of claim 1, wherein, in addition to the first cooling chamber (1a), a downstream cooling chamber (1b) is provided with a solids inlet and a solids outlet, wherein the solids outlet is connected to the inflow. solids of the first cooling chamber (1a).