JPS5815686B2 - High-pressure gas pipe transportation method for pulverized coal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for transporting pulverized coal through a high-pressure gas pipe by filling a pressurized tank with pulverized coal and transporting the pulverized coal through a transport pipe using a transport gas.

In this type of high-pressure transportation method, the material to be transported is combustible pulverized coal, which accumulates in a pressurized tank, so as the pulverized coal oxidizes in the pressurized tank, it generates heat. Conventionally, this method has not been applied to the transportation of pulverized coal due to the risk of ignition and explosion, and because it is pressurized in a pressurized tank, the oxygen partial pressure increases and is dangerous. When inert gas was not supplied to the high-pressure tank, low-pressure, low-density gas transportation methods were mostly used.

Here, the differences between high pressure transportation and low pressure transportation are as shown in the table below.

As a result of various experiments, the present inventor found that the ignition temperature in high-pressure transportation is uniquely related to the partial pressure of oxygen (0□). It was discovered that the oxygen concentration limit at high pressure can be indicated by considering the oxygen concentration at the time as a critical condition for ignition, and this makes it possible to carry out safe transportation, and the present invention is hereby developed. This is what we have come to propose.

The present invention will be described in detail below with reference to the drawings.

In the figure, 1 is a transport line for transporting pulverized coal that has been pulverized and dried by a pulverizer or the like using a carrier gas, 2 is a storage tank that separates the carrier gas from the pulverized coal, 3 is a pack filter, and 4 is an exhaust blower.

The pulverized coal separated by the storage tank 2 is charged into a primary tank 8 via an input valve 6 and an input valve 7, and then intermittently passed through an input valve 9 and an input valve 10 to a pressurized tank 12 having an aerator 11. is supplied to

14 is a transport gas supply source; 15 is a pressurized gas supply control valve; Transport gas such as gas is supplied to the pressurizing tank 12 via the regulating valve 15, and the pressurizing tank 4 is pressurized.

16 is a discharge nozzle extending inside the force meter tank 12;
17 is a transport line connected to a discharge nozzle via a discharge valve 18; 19 is a booster line that supplies transport gas from the transport gas supply source 14 to the transport line 17 via a booster valve 20; and 21 is a combustion line in a blast furnace or the like. Device 22 is a pressure equalization valve that maintains tanks 8 and 12 at equal pressure.

Then, with the pressurized tank 12 filled with pulverized coal, transport gas is supplied into the pressurized tank 12 via the control valve 15 to increase the tank internal pressure, and then the discharge valve 18 and the Puster valve 20 By opening the tank, the pulverized coal in the tank is sent to the transport line 17 together with transport gas at a high solid-air ratio (10 kg/ky or more) and transported to the combustion device 21.

The pulverized coal accumulated in the pressurized tank 12 generates heat as oxidation progresses, and when the temperature reaches the ignition point, ignition, explosion, etc. will occur.

Therefore, in the present invention, a sample of pulverized coal to be transported at the permissible oxygen concentration limit in the pressurized tank 12 is charged into a high-pressure differential thermal balance or a high-pressure differential thermal analyzer, and various oxygen concentrations and actual transport pressures are measured. In addition to measuring the ignition temperature at the bottom, the necessary partial pressure of oxygen (02) is selected from the transportation operating pressure and is set based on that value.

The reason for this is that the high-pressure differential thermal analyzer (TGA) and high-pressure differential thermal analyzer (DTA) have the configurations shown in Figures 2 and 3, respectively, and these include, for example, 46.9% fixed carbon,
Approximately 13 mg of Australian coal sample with volatile content of 35.6%, ash content of 17.5%, and moisture of 1.5% was charged and the pressure was 10kg/cm.
As a result of measurement at a heating rate of 20° C./min in an atmosphere of 2G and 60 g of oxygen, a temperature curve A, a differential temperature curve B, and an excursion temperature curve C shown in FIGS. 5 and 4 were obtained.

As is clear from FIG. 4, the ignition phenomenon a occurred at a pulverized coal temperature of 223°C, and the ignition phenomenon a occurred again at a temperature of 409°C.

On the other hand, the differential thermal temperature indicates the first ignition phenomenon a, as shown in Figure 5.
A weight increase d occurred before and then decreased.

FIG. 6 shows the results of measurements similar to those described above with various changes in pressure and oxygen concentration.

Furthermore, the relationship between pressure, oxygen concentration, and ignition temperature is shown in FIG.

From this figure, oxygen concentration is 15 to 100%, pressure is O to 50 kg.
/cm2G, it can be understood that the ignition temperature falls within the range of 200 to 260°C.

Treating this as a first-order coal oxidation reaction, InC02
=-E/R(1/T)+In(γs/A)-InS, where C02 is the oxygen concentration at the ignition temperature (mol/
Z), T is the ignition temperature (0K), and E is the activation energy (
cot/mot) R is the gas constant (cot/mot'K)
r is the oxygen consumption rate (mol/cm2-8), S is the reaction area (Cm3), and A is the frequency factor (-) in the Av=Us formula.

FIG. 8 shows the relationship between pressure oxygen concentration and deviation temperature, and FIG. 9 shows the relationship between pressure/oxygen concentration and ignition temperature.

From these figures, the relationship between pressure, oxygen concentration, and ignition temperature is
It has been found that this can be treated as a relationship between the oxygen molar concentration at the ignition temperature and the ignition temperature, and based on this it has become possible to perform safety checks under the operating conditions of the transportation device.

However, in this case, it is necessary to consider the amount of transportation and the amount of external energy.

The relationship between the particle size of pulverized coal, the type of coal/coke, and the ignition temperature is shown in Figure 10. This figure shows that the ignition temperature decreases rapidly when the particle size ranges from 60 to 100 mesh. It is understood that there is no significant difference between before and after, and that if there are many volatile components, the ignition temperature decreases, and that Fluid Coke has a high ignition temperature.

Furthermore, the region where no ignition phenomenon occurs with the Mengzhou coal sample is the first region.
As shown in Figure 1.

As described above, according to the method of the present invention, a sample of pulverized coal to be transported is charged into a high-pressure differential thermal balance, and the ignition temperature at each concentration of oxygen is determined under the operating conditions and pressures of the high-pressure gas pipe transport equipment. At the same time, the necessary oxygen partial pressure is selected from the operating pressure, and the permissible oxygen concentration in the pressurized tank is set based on that value, thereby preventing ignition phenomena caused by differences in the type of pulverized coal in the pressurized tank. It has the great feature of being able to reliably prevent this and safely transport high-pressure gas of pulverized coal.

Next, another embodiment of the present invention will be described with reference to FIG.

In this example, in addition to the above-mentioned example, the carbon monoxide concentration, temperature, and temperature rise rate in the pressurized tank 12 are measured and controlled so that these do not exceed the permissible values.

That is, the pulverized coal accumulated in the pressurized tank 12 generates carbon monoxide and heat of oxidation as its oxidation reaction progresses, so by monitoring the carbon monoxide temperature in the pressurized tank, The state of heat generation can be detected indirectly, and the state of heat generation can be directly detected by measuring the temperature and the rate of temperature rise.

Accordingly, in FIG. 12, a thermometer insertion opening 23 is formed in the lower outer wall of the pressurized tank 12, and an electric thermometer 24 is inserted into the pressurized tank 12 through this insertion opening.

An example of the thermometer 24 is a protection tube 25 as shown in FIG.
A resistance temperature detector 26 is disposed inside, and a lead wire 27 of the resistance temperature detector 26 is dedicated to the outside.

In addition, a porous body 28 having air permeability made of a sintered body of ceramic or metal particles (for example, sintered metal) is disposed at the lower part of the protection tube 25 inserted into the tank to form a ventilation hole. The gas inside the tank is introduced into the protective tube 25 through this vent hole.

The lead wire 27 of the thermometer 24 is connected to a measuring circuit 30, and a current value proportional to the temperature inside the tank is obtained from this circuit 30, which is supplied directly and via a differential circuit 31 to a control device 32. be done.

On the other hand, the gas in the tank introduced into the protection tube 25, that is, the carrier gas, and the mixed gas such as carbon monoxide generated from the pulverized coal accumulated in the tank are passed through the conduit 33 communicating with the protection tube 25, for example, by an infrared absorption It is supplied to a carbon monoxide analyzer 34 and, for example, a magnetic detection type oxygen concentration analyzer 35, and electrical outputs corresponding to the carbon monoxide and oxygen concentrations are obtained from these analyzers 34,35, and these are supplied to the control device 32. is supplied to

The control device 32 controls the set upper limit values, that is, the values selected based on known safety conditions, such as a temperature of 60° C. or less, a temperature increase rate of 10° C./h, and a carbon monoxide concentration of 20 inches or less, and a predetermined safety factor. As set in the first embodiment, the acid! The concentration value is compared with the outputs of the temperature measurement circuit 30, differentiation circuit 31, carbon monoxide analyzer 34, and oxygen analyzer 35, and when each detected output exceeds the set value, an alarm circuit 36 such as a lamp or buzzer is activated. At the same time, the control valve 37 is operated to fill the pressurized tank 12 with a fire extinguishing halogenated hydrocarbon (for example, CF).
3Br, CBr2-CIF2. CBrF2CBrF2)
, C02, N2, lime charcoal, carbon powder, and other suppressive/cooling agents.

According to the above configuration, the resistance value of the resistance temperature detector 26 of the thermometer 24 is proportional to the temperature inside the tank, and therefore the measurement circuit 3
An electrical output representing the temperature inside the tank is obtained from 0, an electrical output representing the temperature rise rate is obtained from the differentiating circuit 31, and a carbon monoxide analyzer 34 generates an electrical output representing the temperature in the tank. An electrical output representative of carbon monoxide concentration is obtained.

Since these are respectively supplied to the control device 32, in the normal state where each detection output is below the set upper limit, the alarm drive output SA and valve operation output SO cannot be obtained from the control device 32, and the temperature inside the tank increases. When an abnormal state occurs in which the concentration of carbon monoxide increases, the control device 32 outputs an alarm drive output SA.
is obtained, a visual and/or audible alarm is issued from the alarm circuit 36, and the valve 37 is operated by the valve operation output SO to inject suppressor/coolant into the pressurized tank 12, thereby expanding the abnormal condition. is prevented.

As described above, according to this embodiment, in addition to the effects of the first embodiment, the temperature, temperature increase rate, and carbon monoxide concentration in the pressurized tank are detected and controlled so that these do not exceed the set upper limit values. This allows us to provide a safer and more efficient method of transporting pulverized coal, and in addition, carbon monoxide is detected by forming a vent in the thermometer's protective tube and guiding it outside through the protective tube. This eliminates the need to separately install temperature and carbon monoxide detection ends in the pressurized tank, reducing the number of separate parts, and also allows ventilation holes to be formed on the bottom of the protective tube. Because of this, it has excellent effects such as no clogging caused by pulverized coal.

In the above row, the case where the thermometer 24 is a resistance thermometer has been described, but the thermometer 24 is not limited to this, and may be any other device that can provide an electrical output, such as a thermocouple thermometer.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of the present invention, FIGS. 2 and 3 are cross-sectional views showing a high-pressure differential thermal balance and a high-pressure differential thermal analyzer, and FIGS. 4 to 11 are used to explain the present invention. A diagram showing measured values, FIG. 12 is a system diagram showing another example of the present invention,
FIG. 13 is a sectional view showing one row of thermometers. 12 is a pressurized tank, 14 is a transport gas supply source, 17 is a transport line, 19 is a booster line, 24 is a thermometer, and 34 is a carbon monoxide analyzer.

Claims (1)

[Claims] 1. In a high-pressure gas pipe transport method in which pulverized coal is filled in a pressurized tank and transported through a transport pipe using a transport gas, a sample of the pulverized coal to be transported is transported by a high-pressure thermal analyzer. Measure the ignition temperature relative to the oxygen concentration under the conditioned pressure, and select the necessary oxygen partial pressure from the transportation operating pressure.
A method for transporting pulverized coal through a high-pressure gas pipe, characterized in that an oxygen concentration limit in a pressurized tank is set based on the value. 2. In the high-pressure gas pipe transport method in which pulverized coal is filled in a pressurized tank and transported through the transport pipe using transport gas, a sample of the pulverized coal to be transported is measured using a high-pressure thermal analyzer to determine the oxygen concentration under transport conditions and pressure. In addition to measuring the ignition temperature for the
The oxygen concentration limit in the pressurized tank is set based on the value, and the temperature and/or carbon monoxide gas concentration at the bottom of the pressurized tank is measured, and the upper limit of the temperature rise rate and/or carbon monoxide gas concentration is exceeded. A method for transporting pulverized coal through a high-pressure gas pipe, which is characterized by monitoring and controlling the pulverized coal to prevent it from occurring. 3. A breathable porous body is placed on the bottom surface of the thermometer's protective tube,
3. The method according to claim 2, wherein the carbon monoxide concentration generated from the pulverized coal accumulation surface in the pressurized tank is sampled.