CN103791513A - Energy-saving efficient vaporizer for dimethyl ether gas-fired boiler - Google Patents

Abstract

An energy-saving and high-efficiency vaporizer for a dimethyl ether gas-fired boiler, which consists of a vaporizer body (1), a heat exchange coil (2), an electric heating tube (3), a gaseous fuel outlet (4), a liquid fuel inlet (5), and a circulation Water pump (6), serpentine heat exchange tube (7), thermocouple (8), lower louver baffle (9), upper louver baffle (19), middle partition wall (10), tail flue (11) ; During the start-up period of the boiler, the fuel is vaporized in the form of electric heating; during the normal operation of the boiler, the fuel is vaporized in the form of flue gas waste heat heating, and the amount of fuel vaporization is adjusted by adjusting the amount of flue gas flushing. The invention overcomes the problems of poor control performance, low safety and stability of the traditional water-bath vaporizer, and has the advantages of low power consumption, good economy, and high thermal efficiency of the unit; it can safely and stably supply a sufficient amount of gaseous gas to the burner Dimethyl ether, especially suitable for large-capacity dimethyl ether gas-fired industrial boilers.

Description

An energy-saving and high-efficiency vaporizer for a dimethyl ether gas-fired boiler

technical field

The invention belongs to auxiliary equipment and systems of gas boilers, in particular to an energy-saving and high-efficiency vaporizer for dimethyl ether gas boilers.

Background technique

Dimethyl ether is a new type of clean fuel developed in recent years. It can be produced from traditional fuels such as coal and biomass on a large scale. It has the characteristics of cleanness, high efficiency, safety and environmental protection. It is the first to be researched by major advanced countries in the world. Object. Relevant studies have proved that DME has no residual liquid and residue emissions during the combustion process, and the emissions of CO and major air pollutants are very low; the calorific value of DME/air premixed gas per unit volume is larger than that of traditional gas fuels; combustion efficient. As a fuel, dimethyl ether is currently mainly used in automobiles, civilian stoves, etc., to replace part of diesel and liquefied petroleum gas. Promoting the application of dimethyl ether in the field of industrial boilers is of great significance for promoting my country's energy conservation and environmental protection. However, since dimethyl ether is in a gaseous state at normal temperature and pressure, it is usually stored in a liquefied gas cylinder after being compressed, so it needs to be vaporized before use. Advanced gas vaporization technology is a key technology for the promotion and application of DME gas-fired boilers. At the same time, gas vaporization needs to absorb a large amount of latent heat of vaporization. Finding cheap vaporization heat sources and improving the economy of vaporizers are also important aspects of research and development of advanced vaporization technology.

The currently known vaporizer patented technologies are mainly divided into two categories: air temperature type and water bath type.

The principle of air-temperature vaporization technology is to vaporize fuel with air as a heat source. Its advantage is that its heat source is cheap air, which can effectively reduce the power consumption of the unit and improve the economy. The disadvantages are: (1) The air-temperature vaporization device has a small heat transfer temperature difference, low heat transfer coefficient, and a large heating area to be arranged, resulting in a large volume and floor area of a single vaporization device. (2) Increasing the air scour speed to enhance the heat exchange effect will lead to an increase in the power consumption of the fan. (3) With the increase of equipment use time, the frosting phenomenon on the heat exchange surface becomes more and more serious, resulting in a great decrease in its vaporization performance. (4) The air-temperature gasification device is only suitable for supplying gas to small-capacity units.

The principle of water-bath vaporization technology is to vaporize fuel with water as the heat medium, and hot water is generally produced by electric heating, such as: "Application of dimethyl ether in industrial boilers and its gas supply device" (application number: 201010548844.1); " An electrothermal economizer for dimethyl ether liquefied gas" (application number: 201120291873.4). Its advantages are large heat transfer temperature difference and heat transfer coefficient, uniform heat medium temperature, stable vaporization performance, and small volume and floor space of a single unit, which is suitable for supplying gas for large combustion equipment. Its disadvantage is that the heat medium is produced by electric heating, which is not economical. Taking dimethyl ether as an example, to vaporize 1.0 tons of liquid dimethyl ether, the minimum power consumption is 114kW·h. Although some water-bath vaporizers use the waste heat of flue gas as the heat source of vaporization (for example: "a dimethyl ether heating device for boiler chimney waste water tank" (application number: 201120212616.7)), but during the ignition of the boiler, there is no high-temperature flue gas for vaporization Heat source, this type of carburetor cannot guarantee sufficient gas for ignition. At the same time, during the operation of the boiler, it lacks effective control and adjustment of the vaporization amount; when the hot water in the water tank boils, the excess steam is discharged to the atmosphere through the emptying pipe, resulting in a reduction in economy; after years of operation, if the exhaust The empty pipe is blocked by scaling, and the water tank is prone to explosion and other accidents under the action of internal boiling water. Therefore, this type of vaporizer has poor performance in terms of economy, safety, stability, etc., and it is difficult to adapt to the popularization and application of dimethyl ether in large-scale combustion devices.

Contents of the invention

The purpose of the present invention is to overcome the deficiency of the above-mentioned background technology, and propose an energy-saving and high-efficiency vaporizer for a dimethyl ether gas-fired boiler. This vaporizer can effectively avoid the low economy, unstable operation and poor safety performance of the existing water-bath vaporizer. , The problem of low degree of automation can adapt to the large-scale development of dimethyl ether gas-fired boilers, and provide sufficient gaseous fuels for them safely and stably.

The energy-saving and high-efficiency vaporizer for a dimethyl ether gas-fired boiler involved in the present invention consists of a vaporizer body, a heat exchange coil, an electric heating tube, a circulating water pump, a serpentine heat exchange tube, an upper louver baffle, a lower louver baffle, and a thermocouple , the tail flue and a partition wall; the heat exchange coil, electric heating tube, and thermocouple are arranged inside the carburetor body; the flow section of the tail flue is divided into upper and lower channels by the partition wall, and the upper The upper louver baffle is installed at the entrance of the channel, and the lower louver baffle and serpentine heat exchange tube are installed in the lower channel along the flue gas flow direction; the tail flue is connected to the boiler body and the chimney in the form of flange connection; The circulating water pump, the serpentine heat exchange tube and the internal cavity of the carburetor body form a closed circulation loop, and the heat medium water circulates in the order of "carburizer body → circulating water pump → serpentine heat exchange tube → carburetor body". The residual heat of the flue gas is transported into the carburetor body to heat the vaporized fuel.

The energy-saving and high-efficiency vaporizer for dimethyl ether gas-fired boilers of the present invention overcomes the problems of poor control performance, low safety and stability of traditional water-bath vaporizers, and has low power consumption, good economy, and high thermal efficiency of the unit; it can be used without configuration Under the premise of a gas storage tank, it can safely and stably supply a sufficient amount of gaseous dimethyl ether to the burner, especially suitable for large-capacity dimethyl ether gas-fired industrial boilers.

Description of drawings

Fig. 1 is the schematic structural diagram of the carburetor described in the embodiment of the present invention;

Fig. 2 is the installation schematic diagram of vaporizer of the present invention in dimethyl ether gas boiler system;

In the above drawings, 1. carburetor body, 2. heat exchange coil, 3. electric heating pipe, 4. gaseous fuel outlet, 5. liquid fuel inlet, 6. circulating water pump, 7. serpentine heat exchange tube, 8. thermocouple, 9. lower louver baffle , 19 upper louver baffle, 10 middle partition wall, 11 tail flue, 12 dimethyl ether storage tank, 13A pressure gauge, 14 gas pressure reducing valve, 15 filter, 16 burner, 17 boiler body, 18 chimney, 20B pressure gauge.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments of the specification.

Example

This embodiment is an energy-saving and high-efficiency vaporizer for a dimethyl ether gas-fired boiler. Its structure is shown in Figure 1. The vaporizer consists of a vaporizer body 1, a heat exchange coil 2, an electric heating tube 3, a gaseous fuel outlet 4, and a liquid fuel inlet 5 , circulating water pump 6, serpentine heat exchange tube 7, thermocouple 8, lower louver baffle 9, upper louver baffle 19, middle partition wall 10, tail flue 11; among them, heat exchange coil 2, electric heating tube 3 and thermocouple 8 are installed inside the carburetor body 1; the gaseous fuel outlet 4 and the liquid fuel inlet 5 are respectively connected to both ends of the heat exchange coil 2 and installed outside the carburetor body 1; the liquid fuel flows through the heat exchange coil 2. Endothermic vaporization: Circulating water pump 6, serpentine heat exchange tube 7 and the internal cavity of vaporizer body 1 form a closed circulation loop, and the heat medium water is as follows: "vaporizer body 1 → circulating water pump 6 → serpentine heat exchange tube 7 →Carburetor body 1" circulates in order to transport the waste heat of the flue gas at the tail flue 11 to the carburetor body 1 for heating the vaporized fuel; the flow section of the tail flue 11 is divided into upper and lower parts by the middle partition wall 10 Channel, the entrance of the upper channel is equipped with an upper louver baffle 19, and the lower channel is installed with a lower louver baffle 9 and a serpentine heat exchange tube 7 in sequence along the flue gas flow direction; the tail flue 11 is flanged to the boiler The body 17 and the chimney 18 are connected.

The vaporizer of the present invention uses electric heating as a vaporization heat source to supply gas to the burner during boiler ignition; and uses flue gas waste heat heating as a vaporization heat source to supply gas to the burner during normal operation of the boiler. At the same time, the carburetor adjusts the temperature of the heat source medium water and the gas production by adjusting the flue gas flushing volume of the serpentine heat exchange tube, and the whole adjustment process is safe, stable and reliable.

The working process of the vaporizer described in the present embodiment is as follows:

During the ignition of the boiler, the electric heating tube 3 works alone to heat the heat medium water as a heat source for vaporization;

After the boiler is in normal operation, the electric heating tube 3 is disconnected, the circulating water pump 6, the serpentine heat exchange tube 7, the upper louver baffle 19 and the lower louver baffle 9 are put into operation to heat the heat medium water as a vaporization heat source;

At the same time, during the operation of the boiler, when the operating conditions of the boiler change (such as boiler load changes), the exhaust gas temperature and the temperature of the heat medium water will change accordingly. At this time, the upper louver baffle 19 and the lower louver baffle The plates 9 can automatically adjust their respective openings according to the hot water temperature measured by the thermocouple 8, and change the amount of flue gas flushing the serpentine heat exchange tube 7 to adapt to changes in boiler gas demand and avoid excess heat at the same time Potential safety hazards caused by accumulation in the carburetor body 1. Under normal working conditions, the upper louver baffle 19 is fully opened, and when the water temperature measured by the thermocouple 8 decreases, the opening of the lower louver baffle 9 automatically becomes larger to ensure that the hot water temperature is stable; if the lower louver baffle 9 When 9 is fully open, if the hot water temperature still cannot be effectively picked up, the opening of the upper louver baffle 19 becomes smaller, increasing the amount of flue gas flushing the serpentine heat exchange tube 7, and raising the water temperature; if the water temperature still cannot be effectively improved, then open The electric heating pipe 3 adopts the form of "electric heating + flue gas waste heat heating" to increase the water temperature and generate sufficient and stable gas; on the contrary, when the water temperature measured by the thermocouple 8 rises, the system disconnects the electric heating pipe 3 in sequence , Increase the opening of the upper louver baffle 19, reduce the opening of the lower louver baffle 9, and adjust the water temperature.

The installation of the vaporizer of the present invention in the dimethyl ether gas boiler system is shown in Figure 2. The carburetor is arranged at the tail flue. During the operation of the boiler, the liquid dimethyl ether in the dimethyl ether liquid storage tank 12 enters the heat exchange coil 2 in the vaporizer body 1, absorbs heat and vaporizes, and converts into gaseous fuel; after that, the gaseous dimethyl ether passes through the gas pressure reducing valve 14 is depressurized and filtered by the filter 15, and then sent to the burner 16 for combustion. A pressure gauge 13 is used to display the pressure of the gas before decompression, and B pressure gauge 20 is used to display the pressure of the gas after decompression.

Claims (1)

1. An energy-saving and high-efficiency vaporizer for a dimethyl ether gas-fired boiler, characterized in that the vaporizer consists of a vaporizer body (1), a heat exchange coil (2), an electric heating tube (3), a gaseous fuel outlet (4), and a liquid fuel outlet (4). Fuel inlet (5), circulating water pump (6), serpentine heat exchange tube (7), thermocouple (8), lower louver baffle (9), upper louver baffle (19), middle partition wall (10), The tail flue (11) is composed of; among them, the heat exchange coil (2), the electric heating tube (3) and the thermocouple (8) are installed inside the carburetor body (1); the gaseous fuel outlet (4), the liquid fuel inlet ( 5) Connect to both ends of the heat exchange coil (2) respectively, and install on the outside of the carburetor body (1); the circulating water pump (6), serpentine heat exchange tube (7) and the inner air The cavity forms a closed circulation loop, and the heat medium water circulates in the order of "carburizer body (1) → circulating water pump (6) → serpentine heat exchange tube (7) → vaporizer body (1)", and the tail flue The waste heat of the flue gas at (11) is transported to the carburetor body (1) for heating vaporized fuel; the flow section of the tail flue (11) is divided into upper and lower channels by the middle partition wall (10), and the entrance of the upper channel The upper louver baffle (19) is installed at the upper channel, and the lower louver baffle (9) and serpentine heat exchange tube (7) are installed in the lower passage along the flue gas flow direction; the tail flue (11) adopts the form of flange connection Connect with boiler body (17) and chimney (18).

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