、HS-LHC900Experimental device for high-temperature heat pipe fluidized bed coal gasification

1.product overview

This product features a detailed design of a sodium heat pipe device and a fluidized bed pyrolysis system based on sodium heat pipes. Design coal based on high-temperature sodium heat pipe/The biomass bubbling bed gasification system mainly consists of coal powder hopper, heating furnace, fluidized bed pyrolysis furnace, heat pipe group, cyclone separator, coal powder filter, tar washing collector, gas dryer, gas buffer tank, gas circulating fan, and data acquisition and analysis system. It is suitable for a wide range of coal types and has high requirements for coal powder particle size.

2.Structural features and working principle

This system is a circulating system (filled with a large amount of inert gas as circulating gas before operation), mainly composed of three small systems: pyrolysis system, purification system, and drying and gas storage system from left to right.

（1）Thermal decomposition system

The pyrolysis system includes coal pyrolysis process and raw material transportation process.

In academic terms, coal pyrolysis refers to the heating treatment of coal by placing it in an isolated air environment, that is, the dry distillation of coal. The specific steps are sealing and heating. In practical design, it is necessary to consider that the pyrolysis process must be continuously supplied with coal samples and the collection and discharge of pyrolysis gas. Therefore, the traditional process is extended and expanded, and the simple coal dry distillation experiment is designed systematically and concretely, so that the entire experiment can be carried out continuously. In the initial design process, the traditional coal heating method was changed to use heat pipe heat transfer heating, thus dividing the entire pyrolysis device into a heating section and a pyrolysis section.

The heating section adopts the method of furnace wire heating, and the selected power is4.5KW 400×50The furnace cover can quickly complete the heating of the heat pipe, as shown in the figure. The heat pipe is heated in the center of the furnace cover, and the outer part is insulated with insulation cotton to prevent temperature loss. The pyrolysis section is usedφ108×3Stainless steel pipes are used as pyrolysis chambers, and insulation is also applied to the periphery. The coal powder carried in the circulating gas will undergo pyrolysis reaction to generate blue charcoal and pyrolysis gas. There are flange connections at both ends, and the coal powder particle size is required to be fine. The feeding section is transported with carrier gas. In order to control the pyrolysis process, we need to regulate the feeding amount and speed, including the airflow speed. The coal powder feeding amount from the feeding bin is controlled by a stepper motor, while the flow rate of the carrier gas is regulated by selecting the power of the circulating pump. In order to keep track of the temperature control inside the furnace at all times, we are still working onKA thermocouple is inserted into it to adjust the heating condition through temperature display, avoiding the occurrence of other situations caused by high temperature.

However, raw material transportation is relatively simple as a whole. After comparing the advantages and disadvantages of various transportation methods and combining them with the design concept, the fluidized bed transportation process was ultimately chosen. The pressure balance between the coal bunker and the pipeline was maintained through pipeline connections, allowing the coal powder to fall by its own weight, and ultimately being carried into the pyrolysis chamber by gas.

（2）Purification system

The purification system consists of three parts: a cyclone separator, a filter, and a tar washing tower. Its purpose is to remove the solid content in the pyrolysis gas and achieve the goal of purifying the coal gas.

（3）Dry

The drying tower is used for drying gas. After the airflow enters the drying tower, the diameter of the pipe becomes wider, which slows down the flow rate and is conducive to drying it. At the same time, in order to improve the drying ability of the tower body to the airflow itself, a segmented drying tower is designed to dry the gas three times in the tower body as needed. The tower body is layered by the tray, so that desiccants with different drying coefficients are placed on different trays, and the moisture absorption ability increases from low to high. Also, because water vapor condenses during movement, a drainage valve is set at the bottom of the tower to facilitate timely emptying of the deposited liquid.

（4）Fluidized bed pyrolysis chamber

Design of pyrolysis chamber: The main body of the pyrolysis chamber is aφ108*3mm, high550mmThe inner cylinder is sealed and welded with blind plates at both ends.

Feed inlet: located at the bottom of the pyrolysis chamber60mmMake a hole at the location, andφ46*3mmThe steel pipe is sealed and welded as a feeding port.

Discharge port: Open a hole in the center of the blind plate at the top of the pyrolysis chamberφ46*3mmThe steel pipe is sealed and welded as a discharge outlet.

Heating:Make a hole in the center of the blind plate at the bottom of the pyrolysis chamber, insert a sodium heat pipe, and seal and weld the joint between the pyrolysis chamber and the sodium heat pipe.

（5）Powder coal bin

The design of the powder coal bin: The upper end is a standard elliptical head and a cylindrical body that is clamped with clamps, sealed with gaskets, detachable, and can be sealed, making it easy to load coal and exhaust air. The lower end has an inclination of30°The conical funnel is sealed and welded to the cylindrical body. The maximum capacity of the powder coal bin is80L.

Blowing port: on the cylinder, away from the clamp50mmSymmetrical opening, andφ38*3mmThe steel pipe is sealed and welded for blowing and air exhaust.

The design requirements for the powder coal bin are sealing, easy to add coal, easy to exhaust air, and there are no requirements for hardness and heat resistance.

（6）Cyclone separator

The main body of the cyclone separator has a diameter of140mm, Gao Wei160mmThe inner hollow cylinder has a lower end with an inclination of27°The cone.

Feed inlet: on the cylinder, from the top60mmAt this point, there is an opening that is tangent to the cylinder and connected to oneφ46*3mmSealed connection of steel pipes.

standpipe:Make a hole at the center of the upper end of the cylinder and insert itφ46*3mmThe steel pipe is inserted to a depth of60mmThe connecting part is sealed and welded to serve as the riser.

Solid discharge port: At the lower end of the conical funnel, connect oneφ46*3mmThe steel pipe is sealed and welded as a solid discharge outlet.

（7）Flip plate feeder

FlapDesign of the feeder: As the fluidized bed requires steady-state operation, feeding stability is necessary. Therefore, a flip plate feeder is selected for feeding, and the motor rotation speed is controlled by the magnitude of the current to control the feeding amount.

（8）Filter tower

Design of the main body of the filtration tower: The main body of the filtration tower has an inner diameter174The wall thickness is3mmThe inner hollow cylinder and tower height800mmThe upper and lower ends of the tower are sealed with a blind plate clamped with clamps.

Feed inlet: located at the bottom of the tower300mmMake a hole at the location, andφ46*3mmSteel pipes are sealed and welded to serve as the inlet for flue gas.

Discharge outlet: Open a hole in the center of the blind plate at the top of the tower, and connect it with oneφ38*3mmThe steel pipe is sealed and welded as a discharge outlet.

Packing partition: located at the bottom of the tower400mm、760mmPlace packing partitions separately, and perform aerobic spot welding on the connection between the partitions and the tower body.

（9）Jacketed heat exchanger

Design of heat exchanger: A direct contact jacket heat exchanger is used for heat exchange. Due to the small processing capacity and production time, there is no need to consider the flushing of flue gas. The significance of heat exchange is to preheat and dry low-temperature flue gas. Considering the convenience of production, it is selectedφ46*3mmThe steel pipe is used as the pipe process,φ82*3mmThe steel pipe serves as the pipe side, with both ends of the pipe side3mmThick steel plates are sealed, and the joint between the shell and the pipe side is sealed and welded.

Low temperature flue gas inlet: located at the lower end of the shell head41mmMake a hole at the location, andφ38*3mmThe steel pipe is sealed and welded as a low-temperature flue gas inlet.

Low temperature flue gas outlet: located at the top head of the shell41mmOpen a hole at the location, andφ38*3mmThe steel pipe is sealed and welded as an outlet for low-temperature flue gas.

（10）Semi coke collection container

Design of semi coke collection container: The main body of the semi coke collection container isφ350mmwall thickness3mmThe inner cylinder of the container is high640mmThe lower end is welded and sealed with an elliptical head, and the upper end is sealed with an elliptical head clamped with a clamp. The maximum capacity of the semi coke container is60L.

Blowing port: symmetrically open holes at appropriate positions on the upper end head of the container, respectively withφ38*3mmSealing and welding of steel pipes.

Coke discharge port: a hole is opened in the center of the bottom head of the container, connected to aφ38*3mmThe steel pipe is sealed and welded as a coke discharge outlet.

（11）Thermal insulation

Considering that the pyrolysis reaction occurs during500-600The pyrolysis is carried out at ℃, and the temperature of the flue gas produced is also relatively high, so it is necessary to insulate the system, which can effectively reduce heat loss and avoid danger.

Design of insulation layer: Considering that the temperature of the flue gas before the tar washing tower is relatively high, all equipment and pipelines before the tar washing tower need to be insulated. Traditional insulation methods are used to wrap around equipment and pipelines50mmThick insulation cotton, wrapped tightly with white iron sheet.

（15）Piping

All pipelines in the entire system are made of standard galvanized steel pipes, with dimensions includingφ38*3mm、46*3mm、16*3mm、59*3mmThe specific size can be selected according to the needs. Pipe connections include elbow connections, straight connections, tee connections, valve connections, and seal welding. The specific processing conditions are subject to actual conditions.

3.Installation and debugging

be based onhigh temperatureThe heat pipecoal/Biomass bubbling bed gasificationThe system mainly consists of coal powder hopper, heating furnace, fluidized bed pyrolysis furnace, heat pipe group, cyclone separator, coal powder filter, tar washing collector, gas dryer, gas buffer tank, gas circulating fan, and data acquisition and analysis systemAccording to the process requirements, equip one set of each of the above equipment separately. In addition, it is equipped with one semi coke collection container and one solvent pump, two Roots flow meters, and several valves and pipelines. Assemble the equipment according to the process before leaving the factory, and pay attention to ensuring sealing between each component during equipment installation.

4.Usage and operation methods

（1）Before starting the system, the required coal powder and inert circulating gas should be prepared in advance, and the coal powder should be loaded into the coal powder feeding hopper. Close all outlet valves and introduce inert gas to check the airtightness of the system. Pay attention to ventilation in the laboratory to prevent gas poisoning.

（2）Turn on the power supply of the combustion chamber, turn on the gas circulation pump, turn on the stepper feeder, and turn on the solvent circulation pump.

（3）Observe whether the temperature, pressure, and flow rate of the fluidized bed in the combustion chamber are normal.

（4）Check the carbon content of the semi coke in the semi coke storage room and adjust the size of the stepper feeder.

（5）Detect the moisture content and tar content of the produced gas, and adjust the ratio of fillers in the drying tower and tar washing tower.

（6）Observe whether there is dust settling in the gas holder and adjust the amount of filling material in the filtration tower.

（7）Observe the size of the pressure gauge and open the Roots flowmeter to release gas when the pressure is too high.

（8）After completing the pyrolysis of the required coal powder, turn off the power supply to the combustion chamber, turn off the stepper feeder, and turn off the solvent pump.

5.Fault analysis and troubleshooting

outside1 Equipment Failure Analysis Table

6.Safety protection devices and accident handling

（1）Safety protection devices and precautions

① Strictly follow and implement relevant national and chemical industry safety regulations. In the work environment, it should be taken seriously to avoid personal injury or equipment damage.

② Before powering on the device, please carefully read the instructions and refer to them to operate, inspect, and test the device.

③ Do not touch the circuit during operation, as there may be fatal voltage and current.

④ Do not disassemble device components during system operation, and avoid touching circuits or poisoning.

⑤ Both the heating furnace and pyrolysis furnace operate at high temperatures during system operation. To avoid burns during operation, a high-temperature hazard do not touch sign should be posted outside or insulation cotton should be wrapped around the heating furnace and pyrolysis furnace to prevent burns.

⑥ Before operating the system, check for any gas leaks to avoid gas poisoning.

（2）Procedures and methods for handling malfunctions or accidents

①If a gas leak is found, the power should be turned off in a timely manner, ventilation should be carried out, and the leak point should be checked and repaired.

② If the system is found to be operating abnormally, the power should be turned off in a timely manner and checked according to the instructions.

7.Maintenance and repair

Proper maintenance and repair can better utilize the performance of equipment and extend its service life, so it is necessary to regularly maintain and upkeep the equipment.

（1）Gas circulation pumps and solvent pumps should regularly clean the inside and outside of the fan, the air passage of the fan, and remove surface dust. If a large amount of dust accumulates and the heat dissipation effect is poor, it will cause an increase in temperature, a decrease in air volume, and an increase in vibration, leading to malfunctions. The bearings, oil seals, mufflers, blades, etc. of the fan are consumables and therefore have a certain lifespan, requiring regular replacement. The bearings of the turntable rotating device should be regularly inspected, and lubricating oil should be added or replaced to prevent a lack of oil from causing the temperature of the transmission components to rise, resulting in damage to the shaft.

（2）Filter towers, tar washing towers, and drying towers should be regularly cleaned or their internal fillers replaced. If dust, tar, etc. accumulate, it will cause a decrease in ventilation volume, an increase in internal air pressure in the system, and affect the normal operation of fluidization state. It can also cause a decrease in the purity of the produced gas.

（3）The pyrolysis chamber, cyclone separator, and semi coke container should be regularly cleaned of internal ash residue. If a large amount of ash accumulates, it will also cause a decrease in ventilation volume, an increase in internal air pressure in the system, and affect the normal operation of the fluidized state.

（4）Each valve should be checked regularly, and oil must be added before use. The lubricating oil is5#, 7#Mechanical oil, if lacking in oil, can cause malfunctions such as air leakage or damage. When water accumulates in the drying tower, it should be discharged in a timely manner.

（5）When the equipment is frequently used, the system should be checked for air leakage before each start-up. The maintenance cycle during normal operation is once a week. If there is any abnormal operation, it should be inspected before each start-up.

（6）When the device is idle and not in use, it should be started every ten days and run for a considerable amount of time0.5Hour by hour, to prevent the air valve or cylinder from being damaged due to the lubricating oil drying up over time. At the same time, prevent the components of the electronic control device from being damaged by moisture.