Sampling tube, sampling unit and ammonia emission monitoring system

Abstract

The utility model relates to a kind of sampling tubes, including first end and second end opposite with first end, first end is inserted into sample source, for collecting sample from sample source, sampling tube is multilayer design and can include: inner tube, inner tube is arranged in the radial inside of sampling tube, for guiding sample;And heating device, heating device is arranged in the radial outside of at least part of inner tube, and the power density of heating device at least partially increases from first end towards second end, so that the difference between the maximum value and the minimum value of the temperature of sample in inner tube is less than 90 degrees Celsius.This arrangement can make the temperature uniformity deviation of sampling tube smaller, can adapt to different types of heat preservation structure of flue, avoid ammonia to produce undesirable chemical reaction and physical adsorption as far as possible, so as to reduce jam, and improve measurement accuracy.The utility model also relates to a kind of sampling unit and a kind of ammonia emission monitoring system.

Claims

1. A sampling tube (100) comprising a first end (101) and a second end (102) opposite to the first end, the first end (101) being inserted into a sample source (110) for collecting a sample from the sample source, characterized in that, The sampling tube (100) is a multi-layer design and includes: Inner tube (10), the inner tube being disposed radially inside the sampling tube (100) for guiding the sample; and A heating device (20) is disposed radially outside at least a portion of the inner tube (10), and the power density of the heating device (20) increases at least partially from the first end (101) toward the second end (102) such that the difference between the maximum and minimum temperatures of the sample in the inner tube (10) is less than 90 degrees Celsius.

2. The sampling tube (100) according to claim 1, characterized in that, The sampling tube (100) is provided with multiple sections along the longitudinal direction of the sampling tube (100), and starting from the first end (101), it includes the following sections in sequence: first section (100A), second section (100B) and third section (100C). The power density of the heating device (20) installed in the third section (100C) is 3.5 to 6 times that of the heating device (20) installed in the second section (100B).

3. The sampling tube (100) according to claim 2, characterized in that, The heating device (20) is not installed in the first section (100A).

4. The sampling tube (100) according to claim 2, characterized in that, The heating device (20) is a heating wire, and the number of turns of the heating wire per unit distance in the third section (100C) is greater than the number of turns per unit distance in the second section (100B).

5. The sampling tube (100) according to claim 1, characterized in that, The sampling tube (100) is provided with multiple sections along the longitudinal direction of the sampling tube (100), and starting from the sample source (110), it sequentially includes: a first section (100A), a second section (100B), and a third section (100C). The heating device (20) is a heating wire. Wherein, the first length (L1) of the first section (100A) is 35 to 45% of the tube length (L) of the sampling tube (100), and no heating wire is provided; Wherein, the second length (L2) of the second section (100B) is 50-60% of the tube length (L) of the sampling tube (100), and the ratio of the power of the heating wire in the second section (100B) to the total power is between 75% and 80%; and Wherein, the third length (L3) of the third section (100C) is 1 to 5% of the tube length (L) of the sampling tube (100), and the ratio of the heating wire power of the third section (100C) to the total power is between 20% and 25%.

6. The sampling tube (100) according to claim 1, characterized in that, It also includes a heat transfer tube (30) disposed between the inner tube (10) and the heating device (20).

7. The sampling tube (100) according to claim 6, characterized in that, Also includes: Thermal insulation layer (40), the thermal insulation layer being disposed radially outside the heating device (20); and The outer tube (50) is disposed on the radial outer side of the insulation layer (40).

8. A sampling unit (1000), characterized in that, The sampling unit includes: The sampling tube (100) according to any one of claims 1-7; A filter device (200) is connected to the second end (102) of the sampling tube (100); and A heating unit (300) that at least partially encloses and heats the second end (102) of the filter device (200) and the sampling tube (100).

9. The sampling unit (1000) according to claim 8, characterized in that, The sampling unit further includes: A jet pump (400) is disposed downstream of the filter device (200), and the sample and standard gas are diluted at the jet pump (400); and A gas splitter (500), located downstream of the jet pump (400), is used to separate nitrogen oxides. The heating unit (300) also encloses and heats the jet pump (400) and the gas distributor (500).

10. The sampling unit (1000) according to claim 8 or 9, characterized in that, The heating unit (300) includes: an insulating aluminum block (301) and a heating rod (302) disposed in the insulating aluminum block.

11. An ammonia emission monitoring system, characterized in that, The ammonia emission monitoring system includes: The sampling tube (100) according to any one of claims 1-7; or The sampling unit (1000) according to any one of claims 8-10.

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