Waste heat recovery water tank

Abstract

A waste heat recovery water tank is composed of a waste heat recovery pipe, a graphite heat exchange device and a heat storage water tank. A graphite heat-conducting plate is made into a graphite heat exchange device, and water in the heat storage water tank is directly heated through the graphite heat exchange device by recovering flue gas waste heat. No water pump and other heating circulating devices exist, the structure is simple, waste heat is recycled, and energy conservation and consumption reduction are achieved.

Description

Technical Field

[0001] The present invention relates to a waste heat recovery water tank, which utilizes the high-efficiency heat transfer characteristics of a graphite heat conduction plate to recover waste heat. Flue gas passes through heat conduction in a graphite smoke tube and a graphite heat conduction strip, and the waste heat is used to heat the water tank. Background Art

[0002] Most existing waste heat recovery devices introduce waste heat into the waste heat recovery device. Usually, a heat exchanger is used to heat a medium that needs to be heated, such as circulating water. The waste heat is used to heat the heat exchanger and the circulating water. The water pump of the water circulation device transports the circulating water to the water tank to store heat, or transports it to the required location. Taking the waste heat recovery of a public kitchen stove as an example, the heat exchanger installed in the combustion stove is arranged in the rear vertical plate of the stove. The heat exchanger is connected to the circulating water pipe. The flue gas of the combustion stove heats the heat exchanger in the rear vertical plate through the rear vertical plate and is discharged from the stove exhaust pipe. The heat exchanger heats the circulating water and transports it to the water tank to store heat. The waste heat recovery device using water as the heat transfer medium has the following deficiencies. In the metal heat exchanger water pipe, scale will form after being used for a period of time. The thermal resistance of the scale is very large. 1 mm of scale is equivalent to the thermal resistance of 40 mm of iron plate, and the thermal efficiency will be greatly reduced; for the metal heat exchanger, the thermal conductivity of the copper pipe is 384 W / m·k, and the thermal conductivity of the iron pipe is 73.3 W / m·k. The thermal conductivity of water at 60°C is only 0.66 W / m·k; the flue gas of the combustion stove has to first heat the metal heat exchanger to absorb heat energy and then heat the water. The thermal conductivity of metal and water is low, the temperature rise is slow, and the efficiency is low; the heat exchanger heating the circulating water can only absorb 40 - 60% of the heat, and there is still heat and carbon monoxide in the flue gas emitted into the room; when the distance and height of the water pump circulating water are relatively far, the energy consumption is relatively high. To solve the above deficiencies, it is necessary to directly heat the water tank without transporting the circulating water and collecting the flue gas of all stoves. Summary of the Invention

[0003] In order to overcome the deficiencies of existing waste heat recovery devices, the purpose of the present invention is to use a heat exchange device made of heat-conducting graphite material to recover all the generated flue gas and directly heat the water in the hot water storage tank. Without a circulating water device, the waste heat recovery cost can be greatly reduced, the heating efficiency can be improved, and the operation and maintenance costs can be reduced.

[0004] Due to its unique grain orientation, the graphite heat conduction plate has more excellent heat conduction performance. It conducts heat uniformly in two directions of the X - Y axis and the Z axis, can withstand a temperature of 400°C, has a low thermal resistance, is resistant to acid and alkali corrosion, can be soaked in water for a long time, is non-toxic and pollution-free. It has excellent mechanical strength, is light in weight, with a specific gravity of only 1.9 to 2.3 grams per cubic centimeter, 25% lighter than aluminum, and is easy to cut, process and operate. It has an extremely high thermal conductivity: 1500 - 2000 W / m·k. The thermal conductivity of copper is 384 W / m·k, which is 3.9 - 5 times higher than that of copper. The heat conduction efficiency is high, and the heating temperature rise is fast.

[0005] The technical solution adopted by the present invention is as follows: A waste heat recovery water tank uses a high-efficiency graphite heat conduction plate to make a graphite heat exchange device, which recovers the waste heat of the flue gas and directly heats the water in the hot water storage tank. There is no heating circulation device such as a water pump, with a simple structure, reduced cost, no space occupation, high efficiency in recovering the waste heat of the flue gas, and greatly reduced energy consumption and equipment maintenance costs.

[0006] The waste heat recovery water tank consists of a waste heat recovery pipe, a graphite heat exchange device, and a hot water storage tank. Taking multiple combustion stoves in a public kitchen as an example, the structure and operation process of the waste heat recovery water tank are described below. It is applicable to other waste heat equipment.

[0007] The waste heat recovery flue pipe has a sufficient flow cross-section. One end is connected to the smoke outlet of the smoke exhaust pipes of multiple combustion stoves, and the other end is connected to the waste heat recovery inlet of the graphite heat exchange device in the hot water storage tank through pipe fittings such as waste heat recovery pipes and elbows, and enters the Q-shaped graphite smoke pipe. The waste heat recovery pipe and the elbows are insulated with a heat insulation layer to prevent heat dissipation and scalding of personnel.

[0008] The graphite heat exchange device is composed of a rectangular graphite smoke pipe and strip-shaped graphite heat conduction strips made of graphite heat conduction plates. The graphite heat conduction strips are vertically fixed tightly around the graphite smoke pipe. The graphite smoke pipe is also provided with graphite heat conduction strips that vertically penetrate and are fixedly sealed inside the graphite smoke pipe. Each layer of graphite heat conduction strips is vertically and horizontally staggered. A Q-shaped or n-shaped graphite smoke pipe connected by a graphite smoke pipe and a graphite elbow is arranged at the lower part of the hot water storage tank. The graphite smoke pipes are arranged in parallel along the four vertical surfaces inside the hot water storage tank from the waste heat recovery inlet. At the smoke outlet of the graphite smoke pipe, the graphite smoke pipe extends out of the water through an upward elbow and is connected to the smoke exhaust pipe and elbow at the upper part of the hot water storage tank. A smoke exhaust axial flow fan is arranged inside the smoke exhaust pipe. The smoke exhaust axial flow fan generates negative pressure to ensure smooth smoke exhaust of the waste heat recovery pipe, and the flue gas is discharged through the smoke exhaust elbow of the graphite smoke pipe, the smoke exhaust elbow, and the smoke exhaust pipe. The four sides of the Q-shaped graphite smoke pipe and the smoke exhaust pipe of the graphite smoke pipe are parallel to the rectangular water tank plate. The connection direction of the graphite smoke pipes can also be designed according to the size and shape of the hot water storage tank to increase the heat exchange area of the graphite heat exchange device. Ensure the sealed fixation of the graphite smoke pipe and the water tank, and the sealed fixation of the graphite smoke pipe and the graphite heat conduction strip. Its characteristics are that one end of the waste heat recovery pipe is connected to multiple waste heat smoke outlets, and the other end is connected to the graphite smoke pipe of the graphite heat exchange device in the hot water storage tank. The graphite heat conduction strips of the heat exchange device are tightly attached to the graphite smoke pipe and are vertically fixed through the inside of the graphite smoke pipe, and are arranged at the lower part of the water tank.

[0009] At the joints of the rectangular graphite flue pipes made of graphite heat-conducting plates and the graphite heat-conducting bars vertically passing through the graphite flue pipes, both need to be sealed and fixed. The graphite heat-conducting bars of the graphite flue pipes extend into the water of the hot water storage tank, maintaining a distance parallel to the tank board and bottom board of the hot water storage tank, and are fixed by welding with the tank board by metal fixing brackets. The graphite heat-conducting bars are fixed tightly to the graphite flue pipes with fixing screws. The graphite heat-conducting bars are clamped by a fixing frame and screws, and the fixing frame is welded to the tank board. Ensure that during installation and transportation vibrations, internal structure deformation or damage is prevented. The periphery of the hot water storage tank is insulated with a heat-insulating layer, and the water tank is fixed on the load-bearing wall or beam column with a bracket and a heat-insulating pad. Increase the installation height. If the pressure of the high-position water tank meets the requirements, a water pump can be omitted.

[0010] The hot water storage tank should be made of 304 stainless steel. Design the size and shape of the water tank according to the environment and requirements. Connect the water inlet pipe and its supporting valves and float valves above the overflow water level at the upper part of the water tank, and the lower part should be provided with the outlets of the water outlet pipe, drain pipe, and overflow pipe and their supporting valves. The graphite heat-conducting bars maintain a distance parallel to the tank board and bottom board of the hot water storage tank. When cleaning the water tank, close the water inlet pipe, open the drain pipe valve to empty the water tank, which will also wash away the sediments on the bottom board of the tank. Then open the water inlet pipe and wash it again with clean water. It is also possible to open the water tank cover and enter it manually for cleaning, then close the drain pipe valve to store water, and the float valve will automatically close the water inlet pipe when the water tank is full.

[0011] Taking the kitchen burner as an example to illustrate the process of recovering waste heat to heat the water tank. When the cooking stove is turned on and working, turn on the exhaust axial flow fan of the waste heat exhaust air duct, generating negative pressure to suck in the high-temperature flue gas generated by the stove combustion. The flue gas enters the Q-shaped graphite flue pipe in the hot water storage tank through the stove exhaust pipe, waste heat recovery pipe, and the smoke inlet of the graphite flue pipe. The flue gas flows in the Q-shaped graphite flue pipe, passes through the graphite flue pipe and the graphite right-angle elbow, and flows towards the exhaust pipe. It then passes through the upward smoke outlet elbow, exhaust elbow, and exhaust axial flow fan of the graphite flue pipe and is discharged from the exhaust port. Recover the high-temperature flue gas generated by the combustion of multiple stoves, and quickly transfer the heat to the water in the hot water storage tank through the graphite flue pipe and the graphite heat-conducting bars. The heated water generates convection to heat the water in the hot water storage tank. Open the water outlet pipe, the water level drops, the float valve opens the water inlet pipe, and tap water is replenished. The cold water sinks, is heated, and rises for convective circulation.

[0012] The graphite flue pipes and graphite heat-conducting bars of the graphite heat exchange device can be flexibly designed in combination with the flue gas volume recovered from multiple stoves and the size and shape of the selected hot water storage tank. It can be designed in combination with various waste heat heat sources, having a broad application space.

[0013] The present invention has the following advantages compared with the existing technologies: The graphite heat exchange device of the waste heat recovery water tank does not require a circulating water device. The hot gas of the waste heat heat source is directly introduced into the graphite heat exchange device, and the waste heat flue gas is utilized to directly heat the hot water storage tank, reducing the energy consumption of the circulating water.

[0014] The horizontal and vertical graphite heat conduction bars and graphite smoke pipes of the waste heat recovery water tank greatly increase the heat conduction area. There is no need for metal pipes and water flow media for heat transfer and conduction, reducing the heat conduction links. It is directly heated, with rapid heating and temperature rise, greatly improving the heating efficiency.

[0015] The recovery smoke pipe of the waste heat recovery water tank can recover the combustion hot gas generated by multiple stoves, no longer discharging the smoke indoors, reducing the indoor temperature, improving the indoor environment, and saving energy and reducing consumption.

[0016] The graphite heat exchange device of the waste heat recovery water tank uses waste heat smoke to heat the water in the water tank. There is no water circulation device, which simplifies the structure, has a simple manufacturing process, reduces the manufacturing and operation costs, and improves the efficiency. Description of the Drawings

[0017] Figure 1 It is a front view sectional schematic diagram of the waste heat recovery water tank in the embodiment of the present invention.

[0018] Figure 2 is Figure 1 Top view sectional schematic diagram of the waste heat recovery water tank.

[0019] In the figure, F1. Hot water storage tank, F2. Drain pipe and overflow pipe, F3. Liquid level gauge, F4. Outlet pipe, F5. Graphite smoke pipe, F6. Graphite heat conduction bar, F7. Heat conduction bar passing through the graphite smoke pipe, F8. Smoke pipe fixing bracket, F9. Heat conduction bar fixing bracket, F10. Water tank insulation layer, F11. Water inlet float valve, F12. Graphite exhaust pipe, F13. Exhaust pipe, F14. Exhaust axial flow fan, F15. Drain pipe, F16. Graphite smoke pipe elbow, F17. Water tank cover, F18. Water tank fixing bracket R1. Waste heat recovery pipe, R2. Stove, R3. Stove exhaust pipe, R4. Insulation layer, R5. Waste heat inlet, R6. Waste heat recovery pipe.

[0020] The present invention will be further described with reference to the examples shown in the drawings. In the Figure 1 shown waste heat recovery water tank, it is composed of a waste heat recovery pipe R1, a graphite heat exchange device, and a hot water storage tank F1.

[0021] The waste heat recovery water tank uses a high-efficiency graphite heat conduction plate to make a graphite heat exchange device, using the recovered waste heat of the smoke to directly heat the water in the hot water storage tank. There is no heating circulation device such as a water pump, with a simple structure, reduced costs, no space occupation, high efficiency in recovering the waste heat of the smoke, greatly reducing energy consumption and equipment maintenance costs. Taking a combustion stove in a public kitchen as an example, it can be applied to equipment that can introduce waste heat.

[0022] The waste heat recovery pipe R1 has a sufficient flow cross section, one end of which is connected to the smoke outlet of the exhaust pipe R3 of multiple combustion stoves R2, and the other end is connected to the waste heat recovery smoke inlet R5 of the graphite heat exchange device through the waste heat recovery pipe, elbow and other pipe fittings, and enters the Q-shaped graphite smoke pipe. The waste heat recovery pipe and elbow are insulated with an insulation layer R4 to prevent heat loss and scalding of personnel.

[0023] The graphite heat exchange device is a rectangular graphite flue F5 and a strip graphite heat conducting strip F6 made of graphite heat conducting plate. The graphite heat conducting strip is fixed vertically close to the periphery of the graphite flue. The graphite flue is also provided with a graphite heat conducting strip F7 that vertically passes through the graphite flue to fix and seal. Each layer of graphite heat conducting strips is fixed vertically and staggered horizontally and vertically. A Q-shaped or n-shaped graphite flue is formed at the lower part of the hot water storage tank, connected by a graphite flue and a graphite flue elbow F16. The graphite flue is arranged parallel to the four vertical surfaces in the hot water storage tank from the waste heat recovery smoke inlet. At the graphite flue outlet, the graphite flue extends out of the water through an upward elbow and is connected to the exhaust pipe F13 and the elbow at the upper part of the hot water storage tank. An exhaust axial flow fan F14 is arranged in the exhaust pipe. The exhaust axial flow fan generates negative pressure to ensure smooth exhaust of the waste heat recovery pipe, and the flue gas is discharged from the graphite flue exhaust elbow, the exhaust pipe elbow and the exhaust pipe. The four sides of the Q-shaped graphite smoke pipe and the graphite smoke pipe exhaust pipe are parallel to the rectangular water tank plate. The graphite smoke pipe connection direction can also be designed according to the size and shape of the hot water storage tank to increase the heat exchange area of ​​the graphite heat exchange device. Ensure that the graphite smoke pipe is sealed and fixed to the water tank, and the graphite smoke pipe is sealed and fixed to the graphite heat conductive strip. It is characterized in that one end of the waste heat recovery pipe is connected to the waste heat smoke outlet, and the other end is connected to the graphite smoke pipe of the graphite heat exchange device in the hot water storage tank. The graphite heat conductive strip of the heat exchange device is close to the graphite smoke pipe and passes through the graphite smoke pipe to be vertically fixed and set at the bottom of the water tank.

[0024] The joints of the rectangular graphite smoke pipe made of graphite heat conductive plate and the graphite heat conductive strips that vertically pass through the graphite smoke pipe must be sealed and fixed to prevent water from leaking in. The graphite heat conductive strip of the graphite smoke pipe extends into the water of the hot water storage tank, parallel to the tank plate and bottom plate of the hot water storage tank and keeps a distance, and is welded and fixed to the tank plate by the metal smoke pipe fixing bracket F8. The graphite heat conductive strip is fixed to the graphite smoke pipe with a fixing screw, and the graphite heat conductive strip is clamped by the fixing bracket F9 and the screw, and the fixing bracket is welded and fixed to the water tank plate. Ensure that the internal structure is prevented from deformation or damage during installation and transportation vibration. The outer periphery of the hot water storage tank is insulated with an insulation layer F10, and the water tank is fixed to the load-bearing wall or beam column with a hot water storage tank bracket F18 and an insulation pad. Increase the installation height of the hot water storage tank, and the high-level water tank pressure meets the needs, and water can be supplied through the water tank on a daily basis to reduce the energy consumption of the water pump.

[0025] The hot water storage tank shall be made of 304 stainless steel. The size and shape of the tank shall be designed in combination with the environment and requirements. The water inlet pipe and its supporting valves, float valve F11 and liquid level gauge pipe F3 shall be connected above the overflow water level at the upper part of the tank. At the lower part, there shall be outlets for the water outlet pipe F4, drain pipe, overflow pipe F2 and their supporting valves. The graphite heat conduction strips are parallel to the tank board and bottom board of the hot water storage tank with a certain distance reserved. When cleaning the tank, close the water inlet pipe, open the drain pipe valve to empty the tank, which will also wash away the sediments on the bottom board of the tank. Then open the water inlet pipe and clean it again with clean water. It is also possible to manually open the tank cover F17 to enter for cleaning. After cleaning, close the drain pipe valve to store water. When the tank is full of water, the float valve automatically closes the water inlet pipe.

[0026] Taking the kitchen burner as an example, the process of heat recovery for heating the water tank is described as follows. When the burner is turned on and working, turn on the exhaust axial flow fan of the waste heat exhaust air duct to generate negative pressure to suck in the high-temperature flue gas generated by the stove combustion. The flue gas enters the Q-shaped graphite flue pipe in the hot water storage tank through the stove exhaust pipe, waste heat recovery pipe and the smoke inlet of the graphite flue pipe. In the Q-shaped graphite flue pipe, the flue gas flows towards the exhaust pipe through the graphite flue pipe and graphite right-angle elbow pipe, and then passes through the upward smoke outlet elbow of the graphite flue pipe, exhaust pipe elbow and exhaust axial flow fan, and is discharged from the exhaust port. The high-temperature flue gas generated by the combustion of multiple stoves is recovered, and the heat is quickly transferred to the water in the hot water storage tank through the graphite flue pipe and graphite heat conduction strips. The heated water generates convection to heat the water in the hot water storage tank. Open the water outlet pipe, the water level drops, and the float valve of the water inlet pipe opens the water inlet pipe to supplement tap water. The cold water sinks, is heated, and rises for convection circulation.

Claims

1. A graphite heat exchange device made of graphite heat conducting plates for waste heat recovery water tank, characterized in that: One end of the waste heat recovery pipe is connected to the waste heat smoke outlet, and the other end is connected to the graphite smoke pipe of the graphite heat exchange device in the hot water storage tank. The graphite heat conductive strip of the heat exchange device is close to the graphite smoke pipe and passes through the graphite smoke pipe and is vertically fixed, and is arranged at the lower part of the water tank.

2. The waste heat recovery water tank according to claim 1, characterized in that: The graphite smoke pipe and the graphite heat conducting strip are made of the graphite heat conducting plate. The strip graphite heat conducting strip is fixed tightly to and vertically passes through the rectangular graphite smoke pipe, and each layer is fixed in a vertical and horizontal staggered manner.

3. The waste heat recovery water tank according to claim 1, characterized in that: An exhaust axial flow fan is arranged in the waste heat exhaust pipe.

4. The waste heat recovery water tank according to claim 1, characterized in that: The waste heat recovery air duct and the outer periphery of the hot water storage tank are insulated with an insulation layer.

5. The waste heat recovery water tank according to claim 1, characterized in that: The graphite heat-conducting strip of the graphite smoke pipe extends into the water in the heat storage tank and is fixed in parallel with the bottom plate of the water tank at a distance by a metal bracket.

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