JP2599357Y2 - Ammonia analyzer - Google Patents

Description

[Detailed description of the invention]

[0001]

Industrial Applicability The present invention is particularly applicable to a sample gas containing N.
The present invention relates to an ammonia (NH ₃ ) analyzer suitable for containing O ₂ .

[0002]

In NH ₃ analysis apparatus of the Related Art Conventionally, a difference amount method, the pretreatment unit, the NO _X line for introducing a sample gas as it is, and NH ₃ line was installed denitration catalyst provided from NO _X line N in collected sample gas
While the O concentration is measured as it is, on the NH ₃ line, as shown by the reaction formula of NO + NH ₃ +1/4 O ₂ → N ₂ +3/2 H ₂ O, NO and NH ₃ are 1: 1. The NO concentration after the equivalent reaction was measured, and the NH ₃ concentration was determined from the difference between the NO concentration measured by the NO _X line and the NO concentration measured by the NH ₃ line.

[0003]

[Problems to be Solved by the Invention] By the way, as shown by the reaction formula of NO ₂ +4/3 NH ₃ → 7/6 N ₂ + 2H ₂ O, NO ₂ gas does not react equivalently with NH ₃ , N
Reacts with more NH ₃ than with O.

Therefore, when NO ₂ is contained in the sample gas, a large error has occurred in the measurement accuracy itself by the difference method. That is, if NO ₂ is present in the NO _X line, drain is generated in the sampling pipe at the subsequent stage, neutralization reaction with coexisting NH ₃ is performed as shown in the above equation, or NH ₃ is drained. to or dissolved in, loss has occurred in the NO _X components to be measured. In particular, since the exhaust gas from the gas turbine for power generation contains a relatively large amount of NO ₂ , a countermeasure has been desired.

The present invention has been made in view of such circumstances.
It is an object of the present invention to provide an NH ₃ analyzer capable of accurately measuring the NH ₃ concentration even when NO ₂ coexists in a sample gas.

[0006]

According to the present invention, the means for solving the above-mentioned problems are constituted as follows. That is, it has a pretreatment device consisting of a first flow passage for directly introducing the sample gas and a second flow passage provided with a denitration catalyst in the middle, and the NO concentration of the sample gas introduced from both the flow passages respectively In the ammonia analyzer that detects and calculates the NH ₃ concentration from the difference ,
Be reduced to NO NO _X contained in the pretreatment device
In order to reduce the NO _X to NO, a NO _X converter for reducing the NO _X into NO is provided for both the flow paths, and a NO _X converter is further provided for the second flow path.
Then, the sample gas reaches the denitration catalyst
The NO _X converter so that NO _X is reduced to NO
It is characterized in that it is provided on the upstream side of the denitration catalyst .

[0007]

[Action] By NO ₂ in the sample gas by NO _X converter provided upstream of the denitration catalyst in the pre-processing apparatus is reduced to NO, NO in the sample gas ₂
Is removed. Therefore, NO and NH ₃ are removed by the denitration catalyst.
Can be reacted in an equivalent amount.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
FIG. 1 shows, for example, NH _{3 in} exhaust gas of a gas turbine for power generation.
1 shows a cross section of a sampling probe (a pretreatment device) 1 of an ammonia analyzer for measuring a concentration with a difference method with high accuracy, and reference numeral 2 denotes a flue through which exhaust gas flows, and reference numeral 3 denotes a flue 2 thereof. The sampling probe 1 is attached through a pipe 3 through the pipe.

[0009] The sampling probe 1 is formed in a double pipe structure, NO _X line (first flow path) 6 between the outer pipe 4 and the inner pipe 5 is also inside of the pipe 5
NH ₃ lines (second flow paths) 7 are formed therein, and a denitration catalyst 8 is provided in the pipe 5.

The denitration catalyst 8 is formed by coating a substrate made of TiO ₂ with tungsten (W), vanadium pentoxide (V ₂ O ₅ ), etc., and converts NH ₃ in the sample gas to N 2.
By performing an equivalent reaction with O, so-called denitration is performed.

[0011] 9 is NO _X converter disposed upstream of the pipes 4 and 5, made of graphite, even low rates of adsorption of NH ₃ is consumed less in the flue 2 which is a high temperature, efficiency NO ₂ can be well converted to NO. Thus, this NO _X converter 9, NO _X
Included in the sample gas in line 6 and NH ₃ line 7.
It is possible to reduce all of the NO ₂ contained to NO and accurately measure the NH ₃ concentration.

[0012] More specifically, in NH ₃ line 7, the sample gas up to the denitration catalyst 8, by the NO ₂ is reduced to NO by NO _X converter 9, the denitration catalyst 8, the NH ₃ NO And only the equivalent can be reacted. On the other hand, NO ₂ is also reduced to NO by the NO _X converter 9 in the NO _X line 6. Therefore, NO ₂ is not drained in the piping to the NH ₃ analyzer main body (not shown) at the subsequent stage of the sampling probe 1, or NO ₂ is not dissolved in the existing drain. NO ₂ is or causing neutralization reaction with NH _3, there is no inconvenience such as loss of NO ₂ component itself is generated, it is become possible to measure accurate NH ₃ concentration.

[0013] Incidentally, in the conventional NH ₃ analyzer due to the difference amount method, measurement error due to the coexistence of NO ₂ as calculated from the stoichiometric formula is the NO ₂ is contained 2% in NO _X 4.5
%, 22% at 10%, and 44% at 20%, and the error increases in proportion to the NO ₂ content. However, in practice, as described above, NH ₄ NO ₃ made of the reaction of the dissolution loss and NH ₃ to the drain of NO ₂ in the pipe
There is a concern that, depending on the conditions, a larger error may occur due to drainage of the water.

In this embodiment, taking such points into consideration,
Coexistence of NO ₂ is large, and as a target exhaust gas from the gas turbine for power generation of a large output in a high temperature, by employing a not easily consumed under severe service conditions graphite as NO _X converter 9, as described above Thus, an ammonia analyzer equipped with the sampling probe 1 having good durability and capable of solving the conventional difficulties could be constituted.

The ammonia analyzer is configured to individually detect the NO concentration in the sample gas introduced from the NO _X line 6 and the NH ₃ line 7 and obtain the difference between the NO concentrations. A method of alternately introducing a sample gas from one of the lines 6 and 7 to one NO analyzer and a method of introducing a sample gas from both lines 6 and 7 to two NO analyzers are adopted.

[0016] Figure 2 shows a different embodiment, the distal end portion 4a of the outer pipe 4 is formed in the small-diameter, is obtained by loading the NO _X converter 9 made of graphite at the tip portion 4a.

[0017] Incidentally, NO _X converter 9 is not limited to graphite, it may of course be used other reducing catalyst depending on use conditions.

[0018]

As described above, according to the ammonia analyzer of the present invention , the amount of N contained in the sample gas is reduced.
A NO _X converter that reduces O ₂ to NO
Te provided, is provided with a denitration catalyst for the second channel, de
NO ₂ is reduced to NO which is contained in <br/> sample gas by NO _X converter provided upstream of the sulfate catalyst
As a result, NO ₂ in the sample gas is removed.
Therefore, only NO can be caused to react with NH ₃ equivalently by the denitration catalyst, and NO ₂ in the sample gas introduced from the first channel is also reduced to NO.
Without loss of the NO _X by drainage, etc. of NO _2, NO ₂
The sample gas in which
_{3 The} concentration can be measured accurately.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a sampling probe of the ammonia analyzer of the present invention.

FIG. 2 is a sectional view showing another embodiment of the sampling probe.

[Explanation of symbols]

1 ... pretreatment device, 6 ... first passage, 7 ... second flow channel, 8 ... denitration catalyst, 9 ... NO _X converter.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G01N 31/00-31/22 G01N 1/22 G01N 21/75-21/83

Claims (1)

(57) [Scope of request for utility model registration] 1. A pretreatment device comprising a first flow passage for directly introducing a sample gas and a second flow passage provided with a denitration catalyst in the middle thereof, wherein the NO of the sample gas introduced from each of the two flow passages is provided. The respective concentrations are detected, and N
In the ammonia analyzer obtaining of H ₃ concentration, sump
NO The NO _X contained in the Rugasu in the pretreatment device
To reduced to, NO _X reducing the NO _X in the NO
A converter is provided for the two flow paths, and the second
The sample gas reaches the denitration catalyst in the flow path.
The NO _X Con to the NO _X is reduced to NO in in
An ammonia analyzer , wherein a barter is provided upstream of the denitration catalyst .