KR19990085809A - Wet bulb temperature continuous measuring device - Google Patents

Abstract

The amount of evaporation changes according to temperature and humidity, and the wet bulb temperature is measured by attaching an evaporation device such as a wick to the measuring point of the thermometer and measuring the temperature drop due to evaporation heat due to evaporation. It can be measured. If the humidity is high, the amount of evaporation decreases and thus the heat of vaporization is small, so that the difference from the dry bulb temperature is not large. On the other hand, when the humidity is low, the amount of evaporation increases and the heat of vaporization also increases, thereby increasing the difference between the dry bulb temperature and the wet bulb temperature. In order to continuously understand and control the operation status of the process using such a principle, an electrical output is required. Therefore, in the present invention, a stable high-precision thermocouple is introduced to the wet and dry bulb thermometer and for continuous measurement by processing an electrical signal. A multifunctional recorder and computer were introduced. In addition, the introduction of a thermostat to match the same temperature and humidity conditions as the gas to be measured, a sleep control device to maintain a constant evaporation amount in the wet bulb thermometer according to the humidity conditions, and a preheating device of the feed water using a spiral tube in the thermostat. Etc. were introduced.

Description

Wet bulb temperature continuous measuring device

The present invention relates to a continuous measuring device of wet bulb temperature for determining the humidity of the flowing gas or the room.

Humidity measurement in general living environment can be done by various methods such as wet and dry mouth hygrometer which can be easily found around us, but it can be applied to processes that require control such as manufacturing process of industrial products or production and storage of agricultural products. For this purpose, continuous measurement must be made and the measured value can be converted into an electrical signal and output. However, the conventional method can not be used to control the process by manual method or it can output the electric signal by continuous measuring method. In most cases, the installation environment is very limited. Therefore, there is a demand for the development of a humidity measuring method or device that guarantees versatility and is simple in structure and easy to install and handle, but also economically secured to a certain extent without being greatly affected by the installation environment.

The proportion of humidity and water in human living environment is sometimes as absolute as air, so the influence of humidity is negligible in the manufacturing process of various industrial products or in the growth or production of agricultural products that dominate many environment around us or provide convenience of living. There are many cases that cannot be. Humidity measurement in general living environment can be done by various methods such as wet and dry mouth hygrometer which can be easily found around us, but it can be applied to processes that require control such as manufacturing process of industrial products or production and storage of agricultural products. For this purpose, continuous measurement must be made and the measured value can be converted into an electrical signal and output. However, the conventional method can not be used to control the process by manual method or it can output the electric signal by continuous measuring method. In most cases, the installation environment is very limited. Therefore, there is a demand for the development of a humidity measuring method or device that guarantees versatility and is simple in structure and easy to install and handle, but also economically secured to a certain extent without being greatly affected by the installation environment.

Recently, as the interest in the environment is increasing, treatment processes using alkali absorbers are actively introduced or developed as a technique for removing substances causing air pollution. Most of the alkali absorbers used in these absorption processes have hygroscopic properties. In order to identify and control these moisture absorption characteristics, humidity must be continuously measured in the process in order to absorb and absorb moisture. Thus, the gas flowing in the process includes high concentrations of acid gas, dust and absorbent particles, etc. And the temperature condition is close to 100 ℃, so general humidity sensor is very difficult to install. Accordingly, it is an object of the present invention to develop a device that can be applied to such a difficult environment and has general purpose and can be used in various humidity measurement and control fields.

Recently, as the interest in the environment is increasing, treatment processes using alkali absorbers are actively introduced or developed as a technique for removing substances causing air pollution. Most of the alkali absorbers used in these absorption processes have hygroscopic properties. In order to identify and control these moisture absorption characteristics, humidity must be continuously measured in the process in order to absorb and absorb moisture. Thus, the gas flowing in the process includes high concentrations of acid gas, dust and absorbent particles, etc. And the temperature condition is close to 100 ℃, so general humidity sensor is very difficult to install. Accordingly, it is an object of the present invention to develop a device that can be applied to such a difficult environment and has general purpose and can be used in various humidity measurement and control fields.

1 is a wet bulb temperature continuous measuring apparatus of the present invention

Figure 2 is a heat insulation humidity control diagram in the spray absorption desulfurization process

3 is the effect of the type of absorbent and the approach temperature on the desulfurization rate

4 is a temperature change during long time operation of the semi-dry desulfurization apparatus

* Explanation of symbols for main parts of the drawings

(1): Gas flow pipe to be measured.

(2): Thermocouple for measuring the dry bulb temperature of the gas to be measured.

(3): Insulation to the gas suction line to be measured is required.

(4) A blower for suctioning gas to be measured.

(5): A thermostat controlled at the same temperature as the gas to be measured.

(6): Wet thermocouple for wet bulb temperature measurement (with wick).

(7): A container in which water for wicking is supplied.

(8): A coil is installed in the thermostat so that the temperature of the water supplied to the vessel is the same as the temperature of the thermostat (gas to be measured).

(9): Thermocouple for thermostat temperature control.

(10): The thermostat is electrically heated so that the temperature is the same by comparing the temperature of the gas to be measured with the internal temperature of the thermostat.

(11): A pipeline for replenishing water evaporated from the wick by means of an external water supply pipe.

(12): A container for storing a reserve for replenishing water evaporated from the wick. The lower ware is an open container so that the same water surface as the container of item 7 is maintained at all times. The vacuum is as high as it is, so your sleep is always constant.

(13): Apparatus for the control of vessels of paragraphs 7 and 12 at the beginning of operation to maintain the same water surface.

(14): Apparatus for continuously recording the dry bulb temperature of the gas to be measured and the wet bulb temperature measured in the thermostatic chamber.

(15): A computer that receives the data recorded in Clause 14 and calculates all the data related to humidity or humidity.

(16): Discharge pipe of gas to be measured introduced into thermostat.

In the present invention, a device capable of continuously measuring wet bulb temperature for determining or controlling humidity in a flowing gas, a stationary container, or indoor gas, and converting the measured data into various information related to humidity is developed. .

The device developed in the present invention is the same as the collecting unit of the measurement gas, the thermocouple for measuring the temperature of the measurement gas and thermostat temperature control thermocouple, thermocouple with wick for measuring the wet bulb temperature, dry bulb temperature of the measurement target gas It consists of a thermostat controlled by temperature (wet bulb temperature measuring device installed inside), a device for supplying water for evaporating wet bulb temperature measuring device, a recorder capable of recording and computing the thermocouple measurement value and a computer connected to it. .

The collecting part of the gas to be measured is composed of a suction pipe of gas and a blower for supplying it to a thermostat where wet bulb temperature is measured. The suction tube should be insulated (insulated) so that it can be continually ensured and as soon as the gas to be measured reaches the thermostat, it can be adjusted to equal the temperature of the thermostat (dry bulb temperature of the gas to be measured).

Any type of thermocouple for measuring dry bulb temperature can be used as long as it can measure a range of 0 to 300 ° C. However, in the present invention, a resistance thermocouple of Pt-100Ω having excellent linearity and accuracy in such a low temperature region is used. The thermocouple for measuring the wet bulb temperature installed in the thermostat also used the same type as the thermocouple for measuring the dry bulb temperature, but a wick was attached so that water evaporated at the end. The wick attached to the thermocouple for measuring the wet bulb temperature is contained in a container which is supplied with water from the outside. The water in the container is supplied through a supply pipe from the outside of the thermostat, and the upper end of the container has a sufficiently reduced cross section so that water evaporates to the thermocouple. It should be made only through the attached wick. In addition, the evaporation vessel should be made of a transparent material so that the surface of the water inside can be confirmed.

The main function of the water supply system is to keep the water level of the evaporation vessel installed in the thermostat constant at all times. In other words, it is a device to supply only the amount of water evaporated from the wick, which is a combination of a sealed container and an open container, and is applied with a classical method. . Using the equilibrium between the vacuum pressure in the sealed vessel and the atmospheric pressure acting on the surface of the open vessel, the surface of the evaporation vessel can be kept the same as the initial operation state. do.

The water supply pipe in the thermostat is constructed in a spiral shape so that the heat transfer is sufficient to reach the temperature in the thermostat before water is supplied to the evaporation vessel in the thermostat. As such, a water supply device and a spiral supply pipe that maintain a constant water surface in the evaporation container and replenish evaporated water become a key part of the present invention.

The recorder for recording the electrical signal output from the thermocouple for measuring dry and wet bulb temperature is a general-purpose continuous recorder that can be used by connecting any type of resistance thermocouple directly. It is useful to have a connector (eg RS-232C port) attached. A computer can be used as long as it is a personal computer (PC) of 16bit or higher in the market, and the humidity calculation can be used by using dedicated software or by writing a simplified program. In addition, by installing an interface card for data acquisition and dedicated software in a personal computer, the recorder can be omitted and the electrical output signal of the thermocouple can be directly connected to the computer.

The gas to be supplied to the thermostat is discharged through the upper part of the thermostat to the gas flow pipe first sucked in. In the thermostat, sufficient flow is maintained so that water evaporated from the wick of the thermocouple for measuring wet bulb temperature does not affect the humidity in the thermostat. The amount of gas to be collected should be determined.

Example

One embodiment of an apparatus developed in the present invention will be described.

The configuration of the present invention will be described with reference to the accompanying drawings, as follows.

A thermocouple (2) for measuring dry bulb temperature is installed in the gas flow tube (1) to be measured, which is connected to the temperature controller (10) and the recording device (14), and the gas suction tube (3) passes through the blower (4). In the wet-bulb temperature continuous measuring device piped to the inlet, the container (7) to be supplied with water for the wick core is placed in the thermostat (5), which is piped to the container (12) for storing the reserves to the container (7) To the same level as the water, and the pipe 11 is piped from the bottom thereof, the water supply pipe 8 in the form of a coil is piped to the container 7 via the coil type, and the adjusting device 13 is installed in the container 12 so that the container ( 7) and the container 12 to adjust to the same water surface, and connecting the recording device 14 in the computer 15, and connected to the thermocouple of the measurement target thermocouple (2) and the material wick (6) and the temperature controller ( 10 is a configuration in which the thermocouple 9 is inserted into the thermostat 5.

In the figure, reference numeral 16 denotes an exhaust pipe of the gas to be measured introduced into the thermostat.

Wet bulb temperature continuous measurement device developed in the present invention is a spray dryer (Spray Dryer) and one of the air pollutant removal technology applied to the semi-dry spray drying desorber (Spray Drying Absorber) or duct injection type desulfurization device such as desulfurization device The present invention can be applied to the control of a desulfurization process using a control or a hygroscopic alkali absorbent, but this embodiment will describe an embodiment of a semi-dry desulfurization device.

Spray dryer absorbtion process (SDA) is a system that combines the advantages of wet desulfurization process and dry desulfurization process. It sprays alkali absorber in the form of slurry, which is a mixture of liquid and solid, in the absorption tank of 120-200 ℃. It is called semi-dry process because it absorbs sulfuric acid in the drying process and discharges it into dry particles and collects it in the dust collector. The liquid absorbent is supplied and treated as solid waste. This process is simpler and smaller than the conventional wet desulfurization process, and can process various kinds of combustion gases discharged from various plants, and does not discharge waste water or sludge. In addition, it has high application power as an auxiliary device of the existing combustion gas treatment system, low investment cost and operation cost, and there is no stack plume problem because the outlet temperature of the gas exiting the baghouse through the absorption tank is higher than the saturation temperature. Recently, interest in this is rapidly increasing.

In the semi-dry desulfurization process, the hot combustion gas discharged from the combustor flows into the absorption tank through the gas distribution port, and reacts with the slurry of fine particles of the adsorbent (slaked lime slurry: average diameter 50㎛) sprayed through the atomizer. 10 to 15 seconds. The reaction product, calcium sulfite or calcium sulfate, is dried inside the tower, and some of it is collected at the bottom of the reaction tower and the other is collected in the dust collector. At this time, the fine spray particles in the dried state are dried before the reaction product reaches the absorption wall outer wall by adjusting the gas distribution, slurry flow rate, and spray particle size, and a part of the dried reaction product falls to the bottom of the absorption tower and is discharged to the conveyor. The remaining dust in the flue-gas treated in the absorption tower is collected by a dust collector installed after the absorption tower. Some of the reaction products (including unreacted absorbers) collected in the dust collector are recycled back to the absorption tower to improve the absorption rate and the evaporation effect of the slurry.

This semi-dry desulfurization process is characterized by the basic device characteristics such as the characteristics of the spraying device and the characteristics of the absorbent used, as well as the stoichiometric ratio, the approach temperature to the saturation temperature, the inlet gas temperature, the inlet SO2 concentration, and the residence time in the reactor. It depends a lot on variables. The water concentration in the absorption tank, that is, humidity, is one of the most important performance factors that determine the total desulfurization performance by determining the drying time of the absorbent particles in which the desulfurization reaction takes place.

When the combustion gas introduced into the Spray Drying Absorber comes into contact with the sprayed slurry droplets, the combustion gas is humidified under adiabatic conditions and the temperature drops to the outlet temperature in a short time. In addition, as the temperature of the sprayed droplets rises, the moisture in the droplets evaporates. The moisture evaporation rate of the droplets is determined by the inlet gas temperature, relative humidity, reactor pressure, approach temperature, and equilibrium humidity of the solid.

The absolute humidity and temperature of the flue gas at the reactor outlet are given along the adiabatic saturation line from the flue gas inlet conditions in the following psychrometric chart. Where approach temperature to adiabatic saturation, or simply approach temperature, △ T is the outlet temperature (Tout) minus the insulation saturation temperature (T _saturation ) of the gas △ T = T _out- T _saturation , so the approach temperature ΔT determines the temperature and absolute humidity of the exhaust gas at the outlet of the spray absorption reactor.

In general, the exit temperature approaches near the adiabatic saturation temperature, and if the temperature is too close, the slurry in the reactor becomes wet so that the absorption reaction between SO _{2 in the} gas and droplets of the slurry is continued, thereby increasing the SO ₂ removal efficiency. However, the solid reactant, which is not completely dried, is attached to the dust removal system at the rear end of the reactor, thereby increasing the load of the dust collector and causing operational problems. In addition, if too high, the utilization rate of quicklime, which is an absorbent, and the SO ₂ removal efficiency are lowered, so that there is an appropriate temperature range. When operating the spray absorption process, it is necessary to maintain the outlet temperature at a proper temperature for the performance or operation of the device. . However, since the load of the boiler that outflows fluctuates frequently, the insulation saturation temperature also changes and the outlet temperature also changes, making it difficult to access the insulation saturation temperature constantly. In general, the insulation saturation temperature can be known by measuring the wet bulb temperature, but manual measurement makes it difficult to efficiently operate the process because it cannot cope smoothly with such changing operating conditions. Therefore, by using the device developed in the present invention can continuously measure the wet bulb temperature and calculate the approach temperature based on the value can be utilized to check and control the operating state of the process. At this time, the installation position of the device developed in the present invention becomes an exhaust gas pipe which is the outlet side of the spray absorption type desulfurization device, and if the pipe is wide enough and the wet bulb temperature measuring device (evaporation container and spiral water supply pipe part) can be made small enough, the exhaust gas If directly installed in the pipeline can be omitted because the thermostat portion in the device described above can be installed greatly simplified the device developed in the present invention.

In the above-described embodiment, the wet-bulb temperature continuous measuring device developed in the present invention has been shown to be able to utilize the semi-dry desulfurization process to identify and control the operation state of the process, but the spray dryer having the structure and operation characteristics similar to the semi-dry desulfurization device ( It can be applied to the operation of Spray Dryer, and it can be applied to almost all the fields where continuous measurement of humidity is required.

By using the device developed in the present invention, the wet bulb temperature is continuously measured in the semi-dry desulfurization process, and the approach temperature to the adiabatic saturation temperature is calculated by using the device, and the effects of various operating variables on the performance can be determined. It can be effectively used for control. The following figure shows the effect of the type of desorbent and the approach temperature on the desulfurization rate in the semi-dry desulfurization process. The desulfurization effect is different depending on the type of absorbent. As the adiabatic saturation temperature approaches, the deactivation rate increases. Here, the approach temperature is a value measured using the device developed through the present invention. In addition, the following figure shows the result of continuous measurement of the gas temperature and flow rate in the device during the long time continuous operation of the semi-dry desulfurization device. The wet bulb temperature and the outlet temperature are measured continuously and the difference is expressed by the approach temperature. It can be seen that can continuously track the analysis.

The wet bulb temperature continuous measuring device developed in the present invention can be utilized for the semi-dry desulfurization process in which the desulfurization rate depends on the humidity condition, and can be utilized to identify and control the operation state of the process. It can be applied to the operation of (Spray Dryer). It can also be applied to almost any field where continuous measurement of humidity in other gases is required, especially where the installation conditions are difficult.

Although the features and effects of the present invention have been described above through specific embodiments, this is for illustrative purposes only, and the effects of the present invention are not limited thereto.

Claims (1)

A thermocouple (2) for measuring dry bulb temperature is installed in the gas flow tube (1) to be measured, which is connected to the temperature controller (10) and the recording device (14), and the gas suction tube (3) passes through the blower (4). In the wet-bulb temperature continuous measuring device piped to the inlet, the container (7) to be supplied with water for the wick core is placed in the thermostat (5), which is piped to the container (12) for storing the reserves to the container (7) To the same level as the water, and the pipe 11 is piped from the bottom thereof, the water supply pipe 8 in the form of a coil is piped to the container 7 via the coil type, and the adjusting device 13 is installed in the container 12 so that the container ( 7) and the container 12 to adjust to the same water surface, and connecting the recording device 14 in the computer 15, and connected to the thermocouple of the measurement target thermocouple (2) and the material wick (6) and the temperature controller ( 10) is a wet bulb temperature continuous measuring device characterized in that the thermocouple (9) is inserted into the thermostat (5).