System for preheating biomass raw materials in heating funnel by utilizing waste heat of boiler flue gas

Abstract

The invention discloses a system for preheating a biomass raw material in a heating funnel by utilizing boiler flue gas waste heat. The system comprises a gasification furnace, a biomass gas boiler, a flue gas heat exchanger and an air heat exchanger, a heating funnel is arranged at the top of the gasifier; the gas inlet end of the biomass gas boiler is communicated with the gas outlet end of the gasification furnace; the gas inlet end of the flue gas heat exchanger is communicated with the gas outlet end of the biomass gas boiler; a circulating water pipeline is connected between the air heat exchanger and the flue gas heat exchanger, and water in the flue gas heat exchanger flows back into the flue gas heat exchanger after passing through the air heat exchanger; and the hot air outlet end of the air heat exchanger is communicated with the heating funnel. The flue gas waste heat recycling device can recycle flue gas waste heat.

Description

Technical Field

[0001] The invention relates to the technical field of flue gas waste heat utilization, and more particularly to a system for preheating biomass raw materials in a heating hopper by utilizing boiler flue gas waste heat. Background Art

[0002] Biomass is a green, zero-carbon, renewable energy source. In the context of global energy transformation and sustainable development, its application is gradually diversifying. Especially in the process of transforming from subsidy-driven to market-driven, non-electric fields such as biomass gasification heating have become an important development direction. Biomass gasification technology is to crack biomass raw materials (such as wood chips, bamboo, rice husks, fruit shells and other agricultural and forestry wastes) at high temperatures to produce combustible gas for heating or power generation.

[0003] At present, the utilization method of biomass gasification is to produce gas through a biomass gasifier, and then supply it to a biomass gas boiler for combustion and heating. The flue gas generated by the combustion of the biomass gas boiler is recovered through equipment such as economizers and energy savers. The recovered heat is mainly used for feed water preheating of the biomass gas boiler or burner air preheating. However, after these treatments, the exhaust temperature of the flue gas is still around 150°C, which means that there is still a large amount of heat energy in the flue gas that is not fully utilized, and there is an obvious problem of energy waste.

[0004] Therefore, it is an urgent problem for technicians in this field to develop a system that can recycle the waste heat of flue gas and use the waste heat of boiler flue gas to preheat the biomass raw materials in the heating funnel. Summary of the invention

[0005] In view of this, the present invention provides a system for preheating biomass raw materials in a heating hopper by using the waste heat of boiler flue gas, which can recycle the waste heat of flue gas.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] The system for preheating the biomass raw materials in the hopper by using the waste heat of boiler flue gas includes:

[0008] A gasifier, wherein a heating funnel is provided on the top of the gasifier;

[0009] A biomass gas boiler, wherein the air inlet of the biomass gas boiler is connected to the air outlet of the gasifier;

[0010] A flue gas heat exchanger, wherein the air inlet end of the flue gas heat exchanger is connected to the air outlet end of the biomass gas boiler;

[0011] An air heat exchanger, wherein a circulating water pipeline is connected between the air heat exchanger and the flue gas heat exchanger, and the water in the flue gas heat exchanger flows through the air heat exchanger and then flows back into the flue gas heat exchanger; the hot air outlet end of the air heat exchanger is connected to the heating funnel.

[0012] The beneficial effect of adopting the above technical solution is that by utilizing the waste heat of the flue gas of the biomass gas boiler to preheat the biomass raw materials, the heat energy in the flue gas can be effectively recovered, energy waste can be reduced, and at the same time the temperature of the biomass raw materials can be increased, the subsequent gasification process can be accelerated, the gas production efficiency of the gasifier can be improved, and efficient energy utilization and energy conservation and emission reduction can be achieved.

[0013] Preferably, the gasification furnace is connected to a blower.

[0014] Preferably, a feeding conveyor belt is arranged outside the heating funnel, and the conveying end of the feeding conveyor belt extends into the interior of the heating funnel. The feeding conveyor belt conveys the biomass raw material into the heating funnel for preliminary heating.

[0015] Preferably, a screw feeder is provided at the bottom of the heating funnel.

[0016] Preferably, a biomass gas pipeline is connected between the gasifier and the biomass gas boiler, and a first induced draft fan is provided on the biomass gas pipeline.

[0017] Preferably, the gas outlet end of the biomass gas boiler is connected to a chimney via a flue gas channel, a second induced draft fan is provided on the flue gas channel, and the chimney is communicated with an air inlet of the flue gas heat exchanger.

[0018] Preferably, a circulating water pump is provided on the circulating water pipeline. Through the connection of the circulating water pump, the flue gas heat exchanger, the air heat exchanger and the fan, the circulating water is used to absorb the flue gas waste heat and transfer the heat to the air, and finally the hot air is sent to the furnace top heating funnel to preheat the biomass raw materials. This process makes full use of the waste heat in the flue gas and improves the energy utilization efficiency.

[0019] Preferably, the air inlet of the air heat exchanger is connected to a fan, the air outlet is connected to an air duct, and the air duct is communicated with the heating funnel.

[0020] Preferably, the side wall of the heating funnel is provided with an exhaust hole, which can discharge the gas in the heating funnel, so that the hot air in the heating funnel performs convection heat exchange with the biomass raw material, thereby achieving preheating of the biomass raw material.

[0021] It can be seen from the above technical solution that, compared with the prior art, the present invention discloses a system for preheating biomass raw materials in a heating hopper using waste heat from boiler flue gas, and its beneficial effects are:

[0022] (1) The present invention utilizes the waste heat of flue gas from the biomass gas boiler to preheat the biomass raw material, thereby achieving effective recovery and reuse of the underutilized heat energy in the flue gas, significantly improving energy utilization efficiency and reducing energy waste;

[0023] (2) At the same time, the increase in the temperature of the preheated biomass raw material can accelerate the subsequent gasification process, thereby improving the gas production efficiency of the gasifier and enhancing the operating performance of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0025] Figure 1 A schematic diagram of the structure of the system provided by the present invention.

[0026] Among them, in the figure,

[0027] 1-gasifier; 2-heating hopper; 3-biomass gas boiler; 4-smoke heat exchanger; 5-air heat exchanger; 6-circulating water pipeline; 7-feeding conveyor belt; 8-biomass gas pipeline; 9-first induced draft fan; 10-smoke channel; 11-chimney; 12-second induced draft fan; 13-circulating water pump; 14-fan; 15-air duct; 16-screw feeder; 17-blower; 18-redirecting roller. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The embodiment of the present invention discloses a system for preheating biomass raw materials in a heating hopper by using waste heat from boiler flue gas, comprising:

[0030] A gasifier 1, a heating funnel 2 is provided on the top of the gasifier 1;

[0031] A biomass gas boiler 3, the gas inlet end of the biomass gas boiler 3 is connected to the gas outlet end of the gasifier 1;

[0032] A flue gas heat exchanger 4, wherein the air inlet end of the flue gas heat exchanger 4 is connected to the air outlet end of the biomass gas boiler 3;

[0033] The air heat exchanger 5 is connected with the flue gas heat exchanger 4 by a circulating water pipeline 6. The water in the flue gas heat exchanger 4 flows through the air heat exchanger 5 and then flows back into the flue gas heat exchanger 4. The hot air outlet end of the air heat exchanger 5 is connected with the heating funnel 2.

[0034] In order to further optimize the above technical solution, the gasifier 1 can be a fixed bed upper suction gasifier; the biomass gas boiler 3 can be a steam boiler, and the external steam supply parameters are determined by the actual needs of the heat user; the biomass gas boiler 3 can be a hot water boiler, and the external hot water supply parameters are determined by the actual needs of the heat user.

[0035] In order to further optimize the above technical solution, the gasifier 1 is connected to a blower 17. The biomass raw material and air are dried, pyrolyzed, oxidized, and reduced in the gasifier 1 to produce biomass gas; the blower 17 provides power to send air into the gasifier 1 to participate in the gasification process.

[0036] In order to further optimize the above technical solution, a feeding conveyor belt 7 is arranged outside the heating funnel 2 , and the conveying end of the feeding conveyor belt 7 extends into the interior of the heating funnel 2 .

[0037] In order to further optimize the above technical solution, a redirecting roller 18 is provided in the heating funnel 2, and the feeding conveyor belt 7 is wound around the outside of the redirecting roller 18. The feeding conveyor belt 7 changes the conveying direction at the redirecting roller 18 to facilitate the biomass material to enter the heating funnel 2.

[0038] In order to further optimize the above technical solution, a screw conveyor 16 is provided at the bottom of the heating hopper 2. The screw conveyor 16 can evenly add biomass into the gasifier 1.

[0039] In order to further optimize the above technical solution, a biomass gas pipeline 8 is connected between the gasifier 1 and the biomass gas boiler 3 , and a first induced draft fan 9 is arranged on the biomass gas pipeline 8 .

[0040] In order to further optimize the above technical solution, the gas outlet of the biomass gas boiler 3 is connected to a chimney 11 through a flue gas channel 10 , a second induced draft fan 12 is provided on the flue gas channel 10 , and the chimney 11 is connected to the air inlet of the flue gas heat exchanger 4 .

[0041] In order to further optimize the above technical solution, an SNCR reactor, an SCR reactor, an economizer and an energy saver are sequentially arranged on the flue gas channel 10 between the gas outlet of the biomass gas boiler 3 and the inlet of the second induced draft fan 12; a desulfurization and dust collector is arranged at the bottom of the chimney 11. The SNCR reactor, the SCR reactor and the desulfurization and dust collector can process the flue gas so that the flue gas at the gas outlet of the flue gas heat exchanger 4 can be directly discharged into the atmosphere.

[0042] In order to further optimize the above technical solution, the flue gas heat exchanger 4 and the air heat exchanger 5 are both shell and tube heat exchangers.

[0043] In order to further optimize the above technical solution, a circulating water pump 13 is provided on the circulating water pipeline 6. The circulating water pump 13 is a centrifugal circulating water pump.

[0044] In order to further optimize the above technical solution, a fan 14 is connected to the air inlet of the air heat exchanger 5 , and an air duct 15 is connected to the air outlet, and the air duct 15 is communicated with the heating funnel 2 .

[0045] In order to further optimize the above technical solution, exhaust holes are provided on the side walls of the heating funnel 2 .

[0046] Working principle:

[0047] The gasifier 1 performs gasification, and the generated biomass gas enters the biomass gas boiler 3 after passing through the biomass gas pipeline 8 and the first induced draft fan 9. The flue gas generated by the biomass gas boiler 3 enters the flue gas heat exchanger 4 through the chimney 11. The flue gas heats the circulating water in the flue gas heat exchanger 4. The heated circulating water is transported to the air heat exchanger 5 through the outlet pipe of the flue gas heat exchanger 4. In the air heat exchanger 5, the heated circulating water transfers heat to the air. The cooled circulating water is powered by the air heat exchanger 5 through the circulating water pump 13 and enters the flue gas heat exchanger 4 to continue circulating.

[0048] The high-temperature heat source of the air heat exchanger 5 is the heated circulating water, and the low-temperature heat source is the heated air. The fan 14 provides power to transport the air to the air heat exchanger 5 through the fan outlet duct. The air absorbs the heat of the circulating water in the air heat exchanger 5 to increase its temperature. The heated air enters the furnace top heating funnel 2 through the duct 15 and is discharged from the ventilation holes set on the inner side of the heating funnel 2, thereby preheating the biomass raw materials in the furnace top heating funnel 2 by convection heat exchange.

[0049] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0050] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A system for preheating biomass raw materials in a heating hopper using waste heat from boiler flue gas, characterized in that: include: A gasifier, wherein a heating funnel is provided on the top of the gasifier; A biomass gas boiler, wherein the air inlet of the biomass gas boiler is connected to the air outlet of the gasifier; A flue gas heat exchanger, wherein the air inlet end of the flue gas heat exchanger is connected to the air outlet end of the biomass gas boiler; An air heat exchanger, wherein a circulating water pipeline is connected between the air heat exchanger and the flue gas heat exchanger, and the water in the flue gas heat exchanger flows through the air heat exchanger and then flows back into the flue gas heat exchanger; the hot air outlet end of the air heat exchanger is connected to the heating funnel.

2. The system for preheating biomass raw materials in a heating hopper using waste heat from boiler flue gas according to claim 1 is characterized in that: The gasifier is connected with a blower.

3. The system for preheating biomass raw materials in a heating hopper using waste heat from boiler flue gas according to claim 1 is characterized in that: A feeding conveyor belt is arranged outside the heating funnel, and a conveying end of the feeding conveyor belt extends into the interior of the heating funnel.

4. The system for preheating biomass raw materials in a heating hopper using waste heat from boiler flue gas according to claim 3 is characterized in that: A screw feeder is arranged at the bottom of the heating funnel.

5. The system for preheating biomass raw materials in a heating hopper using waste heat from boiler flue gas according to claim 1, characterized in that: A biomass gas pipeline is connected between the gasifier and the biomass gas boiler, and a first induced draft fan is arranged on the biomass gas pipeline.

6. The system for preheating biomass raw materials in a heating hopper using waste heat from boiler flue gas according to claim 1, characterized in that: The gas outlet of the biomass gas boiler is connected to a chimney through a flue gas channel, a second induced draft fan is arranged on the flue gas channel, and the chimney is communicated with an air inlet of the flue gas heat exchanger.

7. The system for preheating biomass raw materials in a heating hopper using waste heat from boiler flue gas according to claim 1, characterized in that: A circulating water pump is arranged on the circulating water pipeline.

8. The system for preheating biomass raw materials in a heating hopper using waste heat from boiler flue gas according to claim 1, characterized in that: The air inlet of the air heat exchanger is connected to a fan, and the air outlet is connected to an air duct, and the air duct is communicated with the heating funnel.

9. The system for preheating biomass raw materials in a heating hopper using waste heat from boiler flue gas according to claim 1, characterized in that: An exhaust hole is provided on the side wall of the heating funnel.

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