CS242411B1 - The method of partial oxidation of fuels with air-vapor nsbo Oxygen-steam mixtures - Google Patents

Abstract

The invention solves the method of partial oxidation of fuels with air-steam or oxygen-steam mixtures. The essence of the invention lies in the fact that by recognizing oxygen penetrations, the amount of oxygen supplied to the generator and the amount of raw gas produced are measured and the ratio formed from the amount of raw gas per generator unit and oxygen is compared with the required value, depending on the quality of the coal and operating parameters, after which the pressure gasification generator is shut down in case the limit value is exceeded. The invention can be used in all processes of gasification and splitting of fuels, in which a reaction medium containing oxygen is used, e.g. in gasification of coal with an oxygen-steam mixture.

Description

The invention relates to a process for the partial oxidation of fuels with an air-steam or oxygen-steam mixture.

Up to now, in gasification of fuels by partial oxidation of air - steam or oxygen - steam mixtures, the main problem has been the penetration of oxygen into considerably cooler systems of waste heat boilers, coolers and scrubbers connected to a generator or a reactor. In such cases, there is an acute risk of explosion in these facilities where a mixture of oxygen and fuel gases may be formed. Explosions often have devastating effects and should be avoided as much as possible. In general, since oxygen breakthroughs during partial oxidation of fuels cannot be prevented, the destructive effects of the explosion should be avoided by early detection of oxygen breakthroughs and the introduction of safety engineering measures. However, early detection of oxygen ingress is an extremely difficult problem. In partial oxidation processes, such as fixed bed gasification, gas analysis of oxygen in the product gas is used to detect oxygen ingress. The main problems of this method are sampling, treatment and expansion of the gas sample, as well as delays in the overall system. Due to the high dust and tar content, accurate gas sample preparation is only possible at extremely high technical and operating costs. The delay time of this sampling system is in the range of 5 to 10 minutes, even if it works perfectly. However, this delay time is excessive for sudden oxygen breakthroughs. Another way of recognizing is by comparing the flame through the viewing holes. The problem is clogging the observation holes with Etruscan.

These disadvantages are overcome by the object of the invention that, in order to detect oxygen ingress, the amount of oxygen supplied to the generator and the amount of raw gas produced are measured and the ratio produced from the amount of raw gas per generator / oxygen unit is compared to a quality-dependent setpoint. coal and operating parameters, then in the case

- 2 242 411 Exceeding the limit value of the gasification generator shuts down · The possibility of using the ratio of oxygen to raw gas to detect oxygen ingress is that in the event of imperfect oxygen conversion, this ratio is substantially altered. The amount of raw gas produced by the unit generator must also be measured and the ratio of these values must be measured. This makes it particularly problematic to measure the amount of raw gas in unit generators since the raw gas may still contain tar and dust as well as high temperature and water vapor content · Therefore, it is recommended in the solution according to the invention to preferably use a correlation measurement of the quantity of the raw gas. Measurement method · The ratio of oxygen supply to the gas produced is dependent on normal conditions, ie · virtually complete conversion of oxygen, both on coal quality and on the operating parameters of pressure gasification. The limit value of this ratio, at which oxygen penetration is signaled, must therefore be adapted specifically to the existing conditions. · In different pressure gas plants, different limit values should also be expected · Furthermore, in pressure gas plants with higher coal quality fluctuations on coal quality and process parameters.

This adjustment can be done both by manually setting the currently valid limit values and by detecting and entering this limit value via a microcomputer.

An advantage of the present invention is that the operation safety of the pressure generators is greatly increased.

Example

If, in a fixed bed compressed gasification process, the oxygen con- sumption has a specific oxygen demand of 0.14 m ^J in 1 m ^{J of} raw gas in the dry state, the following specific oxygen consumption and oxygen contents - in relation to dry raw gas:

Oxygen Conversion (%) i 100

Měřná spotř. oxygen content (m ^ / np) o, 14 Oxygen content (%) 0

80 0.153 0.169

1.53 3.39

0.189

5.65

Since the lower flammability limit of the mixture of anhydrous raw gas with oxygen is in the range of 5 to 6% oxygen, it

- 3 “242 411 oxygen penetration such a large change in specific oxygen consumption that can be technically measured and identified. The formation in the table of the ratio of the specific oxygen consumption and the amount of dry raw gas requires a conversion of the amount of the mixture of raw gas and oxygen determined by measurement to dry state. The basis for this conversion is the knowledge of the raw gas temperature in the measurement area. Assuming water vapor saturation at this temperature, the amount of raw gas / oxygen mixture to dry state is well possible. The microprocessor can then create a ratio of oxygen consumption to the amount of an anhydrous raw gas / oxygen mixture that is used to detect oxygen ingress.

The invention can be used in all gasification and fuel cracking processes using an oxygen-containing reaction medium, for example, in the gasification of coal with an oxygen-steam mixture.

Claims (2)

OBJECT OF THE INVENTION 1. A method for the partial oxidation of fuels with an air-vapor or oxygen-vapor mixture, characterized in that the amount of oxygen supplied to the generator and the quantity of raw gas produced and the ratio of the raw gas per generator unit and oxygen are compared with a setpoint depending on the quality of the coal and the operating parameters, after which the pressure gasification generator is shut down if the limit value is exceeded. 2. Method according to claim 1, characterized in that the desired value of the coal quality and the operating parameters of the pressure gasification process is set once for a given period of time or adjusted and corrected by a microcomputer.