JPH01318082A - Method for decreasing ammonia concentration of gas from coal gasification - Google Patents

Abstract

PURPOSE:To decrease the NOX concentration of a waste gas by decreasing the NH3 concentration of a gas from coal gasification by providing a specified catalyst layer in a passage for feeding the gas to a burner and injecting a nitrogen oxide and an oxygen-containing gas into the passage on an upstream side of the catalyst layer. CONSTITUTION:A reaction 6 packed with a selective catalytic reduction/ denitrification catalyst in which ammonia is used as a reductant is provided at a position of a gas temperature of 200-500 deg.C of a passage 2 for feeding a gas produced from coal gasification in a coal gasification oven 1 to a gas turbine burner 3; a nitrogen oxide and an oxygen-containing gas are fed from an injector 5 on the upstream side of the reactor 6 to decrease the NH3 concentration of the coal gasification gas and to thereby decrease the NOX concentration of the gas discharged from a gas turbine waste gas pipe 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for reducing ammonia contained in gas generated in a coal gasifier.

[Prior Art] One aspect of a conventional facility that combines a coal gasification furnace and a gas turbine will be explained with reference to FIG.

Since the reaction in the coal gasifier 1 is a reaction in a reducing atmosphere, the gas generated from the coal gasifier in the path 2 to the gas turbine combustor 3 contains a large amount of ammonia <NHI. When gas containing a large amount of laH, is input as gas turbine fuel, the gas turbine combustor 3
, is JIIOX, so the NOX level in the exhaust gas from the gas turbine exhaust gas piping 4 becomes extremely high, which is unfavorable in terms of the Now's forest boundary emission regulations.

[Problem to be solved by the invention]

In view of the above-mentioned technical level, the present invention has been made to solve the problem of Pi in coal gasification gas.
The aim is to provide a purposeful method for reducing n.

[Means for Solving the Problems] The present invention provides a supply route for coal gasification gas generated in a coal gasification furnace to a combustor, in which ammonia is added to a route within a gas temperature range of 200 to 500°C. This is a method for reducing ammonia in coal gasification gas, which is characterized by providing a selective catalytic reduction denitrification catalyst layer as a reducing agent and injecting nitrogen oxide and oxygen-containing gas to the upstream side of the catalyst layer.

The selective catalytic reduction denitrification catalyst using ammonia as a reducing agent used in the present invention is capable of reducing NO in general combustion exhaust gas.
Any denitrification catalyst that can be used to selectively remove K using ammonia as a reducing agent can be used. For example, T10° carrier and active ingredients v, W, MOL.
Those supporting oxides such as Fe and Cu can be used.

Moreover, any shape of the catalyst can be used, but it is preferable to use a honeycomb shape with less pressure loss.

In addition, the installation position of these catalyst layers is such that the gas temperature in the path is 2.
The experimental results of the present inventors have confirmed that the temperature range is preferably 00 to 500°C, and particularly preferably 3σ0 to 450°C.

In the present invention, 1211fL of gas in the path between the coal gasifier and the gas turbine combustor is at a temperature of 200 to 500°C,
The above catalyst layer is installed, and nitrogen oxides (N
O) and oxygen-containing gas (0,) are injected,
This is to cause 0BIB in the gas generated by the coal gasifier to react with an appropriate amount of injected NO and 0, t- to convert it into yHs'+stable N through the reaction of the following formula.

4111i, + 4110 + O, → 41! ffi
+6 O Due to the above reaction, the NO contained in the gas input to the gas turbine combustor is reduced as much as possible and changed to h, so the NOx generated in the gas turbine combustor is low and the amount of NOx in the gas turbine exhaust gas is NOx becomes a low value.

[Implementation row]

Hereinafter, one embodiment of the present invention will be explained with reference to FIG. In FIG. 1, the same reference numerals as in FIG. 5 indicate the same parts as in FIG. 3. 5 is a nitrogen oxide (No) and oxygen-containing gas (O3) injector provided in the coal gasification gas supply route 2;
6 is a reactor filled with a selective catalytic denitrification catalyst using ammonia as a reducing agent.

In the flow shown in Fig. 1, for ME in coal gasification gas, 4NEI, +4NO+O, → 411. FIG. 2 shows the results of injecting NO and O3 corresponding to the +6B,0 reaction and investigating how the above reaction occurred depending on the temperature at the location where the reactor 6 was installed.

Figure 2 is a chart showing the relationship between gas temperature (temperature at which reactor 6 is installed) (℃) and NH removal rate (%). °C, especially 50
It turns out that the temperature within the range of 0 to 450°C is preferable.

Next, at 70- in FIG. 1, the reactor 6 filled with the denitrification catalyst is installed in the path 2 at the optimum temperature point, and (1) 0. When only injecting NO and not injecting NO (comparison method 11), ■N
A case where only O was injected and no injection at 0° was carried out (Comparative Example 2) and a case where both NO and 0° were injected (implementation row) were carried out, and the results shown in the table below were obtained.

〔Effect of the invention〕

NH,′ in the coal gasification gas input to the gas turbine
The degree of a decreases, and 110x (
When the temperature is 14 degrees lower, NOx released into the atmosphere can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the flow of an embodiment of the present invention, and Fig. 2 is a diagram showing the relationship between the installation position of the selective catalytic denitrification catalyst layer using ammonia as the reducing agent and the NH removal rate of the present invention. people,
FIG. 3 is a diagram showing a conventional combination equipment of a coal gasification furnace and a gas turbine.

Claims (1)

[Claims] A selective catalytic reduction denitrification catalyst layer using ammonia as a reducing agent is provided in a route in which the gas temperature is within the range of 200 to 500°C in a supply route of coal gasification gas generated in a coal gasifier to a combustor, and the catalyst layer A method for reducing ammonia in coal gasification gas, characterized by injecting nitrogen oxide and oxygen-containing gas into the upstream side of the coal gasification gas.