Combustion-supporting air pretreatment system of gas furnace

Abstract

The utility model discloses a combustion-supporting air pretreatment system of a gas furnace, which is used for dehydrating wet saturated air to be used as combustion-supporting air, and at least comprises a dehydration unit, a second evaporator and a third condenser, the first evaporator is used for cooling wet saturated air in the atmosphere to a first temperature by utilizing heat absorption gasification of a liquid refrigerant; the first condenser is used for raising the temperature of the low-temperature flue gas from the second temperature to a third temperature by utilizing heat release liquefaction of a gaseous refrigerant; the gas furnace flue gas recovery unit comprises a second condenser and a second evaporator which construct secondary circulation; the second condenser is used for receiving the dried cold air at the first temperature, heating the cold air at the first temperature to a fourth temperature by utilizing heat release liquefaction of a gaseous refrigerant, and taking the cold air as combustion-supporting air of the gas furnace; the second evaporator is used for cooling the high-temperature flue gas at the fifth temperature from the top of the gas furnace into low-temperature flue gas at the second temperature through heat absorption gasification of the liquid refrigerant. The problem that the furnace efficiency is reduced due to rising of the water inlet amount of the gas heating furnace can be effectively solved, energy consumption is low, and operation is easy.

Description

TECHNICAL FIELD

[0001] The utility model relates to a gas heating furnace technical field especially relates to a gas stove combustion -supporting wind pretreatment system. BACKGROUND

[0002] The working process of a gas heating furnace mainly involves a mixing process, an ignition process, a combustion process, and a heat exchange process. The mixing process refers to the process in which fuel gas (such as natural gas) enters a burner through a gas supply system, while air as combustion-supporting wind is sucked in by a fan and mixed with the fuel gas to form combustible gas. The ignition process refers to the process in which an ignition device ignites the mixed gas to generate an initial flame. The combustion process refers to the process in which the initial flame ignites more premixed gas to form a stable flame, so that the fuel gas is fully combusted in the combustion chamber to generate heat. The heat exchange process refers to the process in which the heat generated in the combustion process is transferred to the medium (such as water or steam) in the boiler through a heat exchanger, so that the medium is heated to a set temperature. The heated water or steam is delivered to the place where heating is needed through a pipeline for heating, hot water supply, or other process requirements.

[0003] A gas heating furnace is one of the important energy supply devices in the production process of a refinery. Stable and efficient operation of the heating furnace is one of the important factors for ensuring the quality and quantity of energy supply. At the same time, a decrease in the efficiency of the heating furnace may have adverse effects on production and energy consumption in many aspects, causing a series of problems such as waste of energy resources, reduction of production efficiency, shortening of equipment life, and pollution of the environment.

[0004] In the southeast coastal areas of China, the air is hot and humid for a long time in summer, and the water content in the air is mostly in a saturated state. According to field data, if the saturated humid air is directly used as combustion-supporting wind for the heating furnace, the furnace efficiency of the heating furnace will decrease by 1-2 percentage points, causing problems such as waste of fuel gas resources. The commonly used dehydration methods in the prior art include cooling dehydration, molecular sieve adsorbent dehydration, and triethylene glycol dehydration, etc. For example, Chinese patent CN222110996U discloses an adsorption removal system. In use, the solvent in the storage tank is pumped into the first adsorption tower through the feed pump. The activated carbon distributed in the first adsorption tower adsorbs the impurities in the solvent. The solvent after the first adsorption is subjected to secondary adsorption dehydration by the molecular sieve distributed in the second adsorption tower. When hot water is introduced into the jacket outside the first and second adsorption towers, the adsorption temperature is increased, and the adsorption rate is accelerated. When the adsorbent reaches the saturation state, steam is introduced into the jacket to desorb the target substances from the adsorbent, so as to realize the regeneration and recycling of the adsorbent. The packing support grid is fixed below the adsorption tower, so that the adsorbent is always kept above the packing support grid, and the adsorbent will not flow out with the solvent. The substances after adsorption and dehydration are separated by the precision filter and then enter the adsorption receiving tank. When the liquid level in the adsorption receiving tank reaches a certain level, the substances are transferred to the finished product metering tank.

[0005] However, the above-mentioned dehydration processes have the problem of high energy consumption. Applying this dehydration process to the dehydration of humid air used for combustion air in heating furnaces will result in the external energy consumption of the dehydration process being basically equal to, or even exceeding, the heat loss of the heating furnace. At the same time, the use of adsorbent dehydration and triethylene glycol dehydration requires corresponding regeneration devices, which increases the difficulty of equipment operation and control.

[0006] Therefore, there is an urgent need for a gas-fired furnace combustion air pretreatment system that can effectively solve the problem of reduced furnace efficiency caused by increased water intake in the gas-fired heating furnace, and has low energy consumption and simple operation.

[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this utility model and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Utility Model Content

[0008] The purpose of this utility model is to provide a pretreatment system for combustion air of a gas furnace. It achieves cooling and dehydration of saturated humid air through a primary circulation and recovers waste heat from the flue gas of the heating furnace through a secondary circulation. It can effectively solve the problem of reduced furnace efficiency caused by the increase of water intake in the gas furnace, and has low energy consumption and simple operation.

[0009] To achieve the above objectives, this utility model provides a gas-fired furnace combustion air pretreatment system for dehydrating saturated air and using it as combustion air. The system includes at least: a dehydration unit comprising a first evaporator and a first condenser forming a primary cycle; the first evaporator cooling saturated air in the atmosphere to a first temperature using the endothermic vaporization of a liquid refrigerant; the first condenser raising the temperature of low-temperature flue gas from a second temperature to a third temperature using the exothermic liquefaction of a gaseous refrigerant; and a gas-fired furnace flue gas recovery unit comprising a second condenser and a second evaporator forming a secondary cycle; the second condenser receiving dried cold air at the first temperature and raising the temperature of the cold air to a fourth temperature using the exothermic liquefaction of a gaseous refrigerant, which is then used as combustion air for the gas-fired furnace; and the second evaporator cooling high-temperature flue gas from the top of the gas-fired furnace at a fifth temperature to low-temperature flue gas at the second temperature using the endothermic vaporization of a liquid refrigerant.

[0010] Furthermore, in the above technical solution, in the first-stage cycle, a first-cycle refrigeration compressor is provided on the pipeline from the first condenser to the first evaporator, and a first-cycle refrigeration valve is provided on the pipeline from the first evaporator to the first condenser.

[0011] Furthermore, in the above technical solution, in the secondary cycle, a second cycle refrigeration compressor is provided on the pipeline from the second evaporator to the second condenser, and a second cycle refrigeration valve is provided on the pipeline from the second condenser to the second evaporator.

[0012] Furthermore, in the above technical solution, a liquid separator is connected to the air pipeline between the first evaporator and the second condenser. The air inlet of the liquid separator is connected to the air outlet of the first evaporator, and the dried air outlet of the liquid separator is connected to the air inlet of the second condenser.

[0013] Furthermore, in the above technical solution, the high-temperature flue gas outlet at the top of the gas furnace is connected to the flue gas inlet of the second evaporator.

[0014] Furthermore, in the above technical solution, the flue gas outlet of the second evaporator is connected to the flue gas inlet of the first condenser.

[0015] Furthermore, in the above technical solution, the first temperature is preferably 5°C. The second temperature is preferably 65°C, the third temperature is preferably 85°C, the fourth temperature is preferably 60°C, and the fifth temperature is preferably 110°C.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1) This utility model adopts a two-stage absorption cycle refrigeration. The first-stage cycle can cool and dehydrate saturated humid air, while the second-stage cycle can recover waste heat from the flue gas of the gas furnace. This utility model utilizes the waste heat of high-temperature flue gas and the cooperation of the evaporator and condenser in the two-stage cycle to cool, dry, and heat the humid saturated air in the atmosphere, so that it meets the better moisture index requirements of the combustion air of the gas furnace.

[0018] 2) This utility model reduces the water content in the combustion air from 5% to 0.7% by dehydrating the combustion air, ensuring that the gas furnace can operate efficiently and stably even in the hot and humid summer, thereby reducing fuel gas consumption and achieving energy saving and emission reduction.

[0019] 3) This utility model adopts an absorption-type circulating refrigeration method to dehydrate the combustion air. Compared with conventional molecular sieve dehydration and triethylene glycol dehydration, this method has obvious energy consumption advantages, ensuring the clean and energy-saving effect of dehydration, and is simple and easy to operate.

[0020] 4) This utility model can recover waste heat from the high-temperature flue gas discharged from the gas furnace, and the temperature of the discharged flue gas can be reduced by more than 20°C. The recovered energy can preheat the combustion air and further improve the furnace efficiency, ensuring the stable and high-level operation of the gas power.

[0021] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of this utility model easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a connection diagram of the combustion air pretreatment system for the gas-fired furnace of this utility model.

[0023] Explanation of key figure labels:

[0024] 1-Dehydration unit, 11-First evaporator, 12-First circulating refrigeration valve, 13-First condenser, 14-First circulating refrigeration compressor, 2-Dispenser, 3-Gas furnace flue gas recovery unit, 31-Second condenser, 32-Second circulating refrigeration valve, 33-Second evaporator, 34-Second circulating refrigeration compressor, 4-Gas furnace. Detailed Implementation

[0025] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. However, it should be understood that the scope of protection of this utility model is not limited to the specific embodiments.

[0026] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0027] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0028] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0029] like Figure 1As shown, this utility model provides a gas-fired furnace combustion air pretreatment system for dehydrating saturated air (e.g., the atmosphere in low-latitude regions during summer, where the atmospheric moisture content is high) and using it as combustion air. It includes at least a dehydration unit 1 and a gas-fired furnace flue gas recovery unit 3. The dehydration unit 1 includes a first evaporator 11 and a first condenser 13 to form a primary cycle. The first evaporator 11 is used to cool the saturated air in the atmosphere to a first temperature (preferably 5°C) using the endothermic vaporization of liquid refrigerant. The first condenser 13 is used to heat the low-temperature flue gas from a second temperature (preferably 65°C) to a third temperature (preferably 85°C) using the exothermic liquefaction of gaseous refrigerant. Further... Figure 1 As shown, the gas furnace flue gas recovery unit 3 includes a second condenser 31 and a second evaporator 33 that form a two-stage cycle; the second condenser 31 is used to receive cold air at a first temperature (i.e., the aforementioned 5°C) after drying (preferably by gas-liquid separation) and to raise the 5°C cold air to a fourth temperature (preferably 60°C) by using the exothermic liquefaction of gaseous refrigerant and to use it as the combustion air for the gas furnace; the second evaporator 33 is used to cool the high-temperature flue gas from the top of the gas furnace 4 at a fifth temperature (preferably 110°C) to the aforementioned second temperature (i.e., 65°C) by using the endothermic vaporization of liquid refrigerant.

[0030] Further as Figure 1 As shown, in the aforementioned primary cycle (i.e., the cycle between the first evaporator 11 and the first condenser 13), a first-cycle refrigeration compressor 14 is installed on the pipeline from the first condenser 13 to the first evaporator 11, and a first-cycle refrigeration valve 12 is installed on the pipeline from the first evaporator 11 to the first condenser 13. In the secondary cycle (i.e., the cycle between the second condenser 31 and the second evaporator 33), a second-cycle refrigeration compressor 34 is installed on the pipeline from the second evaporator 33 to the second condenser 31, and a second-cycle refrigeration valve 32 is installed on the pipeline from the second condenser 31 to the second evaporator 33.

[0031] Further as Figure 1 As shown, a separator 2 is connected to the air pipe between the first evaporator 11 and the second condenser 31. The air inlet of the separator 2 is connected to the air outlet of the first evaporator 11, and the dried air outlet of the separator 2 is connected to the air inlet of the second condenser 31. Further as... Figure 1 As shown, the high-temperature flue gas outlet at the top of the gas furnace 4 is connected to the flue gas inlet of the second evaporator 33. The flue gas outlet of the second evaporator 33 is connected to the flue gas inlet of the first condenser 13.

[0032] The operation process of this utility model system will be described in detail below:

[0033] Moist saturated air enters the first evaporator 11 of the dehydration unit 1, where the liquid refrigerant absorbs heat and vaporizes, then passes through the first circulation refrigeration valve 12 (which may be a throttling valve) into the first condenser 13. There, it is condensed into liquid refrigerant by the low-temperature flue gas at 65°C, and then pressurized by the first circulation refrigeration compressor 14 before re-entering the first evaporator 11 for cyclic operation. In the combustion air dehydration unit 1, the low-temperature flue gas flowing through the first condenser 13 is heated from 65°C to 85°C before being discharged, while the saturated humid air is cooled from ambient temperature (>30°C) to 5°C via the first evaporator 11. After reaching a certain temperature, the gas enters the separating tank 2 for separation. The gas exiting the separating tank 2 enters the second condenser 31 in the gas furnace flue gas recovery unit 3. The gaseous refrigerant in the gas furnace flue gas recovery unit 3 enters the second condenser 31 and is condensed into liquid refrigerant by the cold combustion air (i.e., dry air at 5°C). After passing through the second circulating refrigeration valve 32 (or a throttling valve), the pressure is reduced to the evaporation pressure and then enters the second evaporator 33. The liquid refrigerant absorbs heat from the 110°C high-temperature flue gas from the gas furnace 4, vaporizes, and re-enters the second condenser 31 for cyclic operation. In the gas furnace flue gas recovery unit 3, the high-temperature flue gas flowing through the second evaporator 33 is cooled from 110°C to 65°C and then enters the first condenser 13 of the dehydration unit 1. The low-temperature dry combustion air flowing through the second condenser 31 is heated from 5°C to 60°C. The heated dry combustion air enters the gas furnace 4 and reacts with the fuel gas to participate in the combustion process.

[0034] This invention employs a two-stage absorption cycle refrigeration system. The refrigerant can be selected from medium-temperature and medium-pressure refrigerants such as R22 and R404A. The first-stage cycle can achieve cooling and dehydration of saturated humid air, while the second-stage cycle can achieve waste heat recovery from the flue gas of the gas furnace. This invention utilizes the waste heat from high-temperature flue gas and the combined action of the evaporator and condenser in a two-stage circulation system to cool, dry, and heat saturated air in the atmosphere, ensuring it meets the moisture content requirements of the combustion air for gas-fired furnaces. Through dehydration treatment of the combustion air, the water content can be reduced from 5% to 0.7%, guaranteeing efficient and stable operation of the gas-fired furnace even in hot and humid summers, thereby reducing fuel consumption and achieving energy conservation and emission reduction. This invention employs an absorption-type circulating refrigeration method for dehydration of the combustion air. Compared to conventional molecular sieve dehydration and triethylene glycol dehydration, this method has significant energy consumption advantages, ensuring a net energy-saving effect, while being simple and easy to operate. This invention also recovers waste heat from the high-temperature flue gas discharged from the gas-fired furnace, reducing the exhaust gas temperature by more than 20°C. This recovered energy can preheat the combustion air and further improve furnace efficiency, ensuring stable and high-level operation of the gas-fired power system.

[0035] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the present invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the present invention and its practical applications, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the present invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the protection scope of the present invention.

Claims

1. A combustion air pre-treatment system for a gas-fired furnace, characterized by, For using the dehydrated wet saturated air as combustion air, comprising: a dehydrating unit comprising a first evaporator and a first condenser for building a primary cycle; the first evaporator is used for cooling the wet saturated air in the atmosphere to a first temperature by using the endothermic vaporization of liquid refrigerant; the first condenser is used for warming the low-temperature flue gas from a second temperature to a third temperature by using the exothermic liquefaction of gaseous refrigerant; a flue gas recovery unit of gas stove comprising a second condenser and a second evaporator for building a secondary cycle; the second condenser is used for receiving the dry cold air at the first temperature and warming the cold air at the first temperature to a fourth temperature by using the exothermic liquefaction of gaseous refrigerant and as the combustion air of the gas stove; the second evaporator is used for cooling the high-temperature flue gas from a fifth temperature at the top of the gas stove to the low-temperature flue gas at the second temperature.

2. The gas burner combustion air pretreatment system of claim 1, wherein In the primary cycle, a first cycle refrigeration compressor is arranged on the pipeline from the first condenser to the first evaporator, and a first cycle refrigeration valve is arranged on the pipeline from the first evaporator to the first condenser.

3. The gas furnace combustion air pre-treatment system of claim 1, wherein, In the secondary cycle, a second cycle refrigeration compressor is arranged on the pipeline from the second evaporator to the second condenser, and a second cycle refrigeration valve is arranged on the pipeline from the second condenser to the second evaporator.

4. The gas burner combustion air pretreatment system of claim 1, wherein, An air pipeline between the first evaporator and the second condenser is connected with a distribution tank, the air inlet of the distribution tank is communicated with the air outlet of the first evaporator, and the dry air outlet of the distribution tank is communicated with the air inlet of the second condenser.

5. The gas furnace combustion air pre-treatment system of claim 1, wherein, The high-temperature flue gas outlet at the top of the gas stove is communicated with the flue gas inlet of the second evaporator.

6. The gas burner combustion air pretreatment system of claim 1, wherein, The flue gas outlet of the second evaporator is communicated with the flue gas inlet of the first condenser.

7. The gas burner combustion air pretreatment system of claim 1, wherein The first temperature is 5℃.

8. The gas burner combustion air pretreatment system of claim 1, wherein, The second temperature is 65℃, and the third temperature is 85℃.

9. The gas burner combustion air pretreatment system of claim 1, wherein, The fourth temperature is 60℃.

10. The gas burner combustion air pretreatment system of claim 1, wherein, The fifth temperature is 110℃.

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