RU81958U1 - DEVICE FOR MODELING PROCESSES OF THERMAL PROCESSING OF SOLID FUELS - Google Patents

Abstract

1. A device for simulating the process of semi-coking of solid fuel, including a sealed pyrolyzer placed in an electric heating furnace and equipped with thermocouples and steam and gas products, a fuel hopper equipped with an outlet pipe with a valve, a vertical solid heating chamber equipped with thermocouples mounted on a pyrolyzer, placed in a furnace with electric heating and equipped with a loading nozzle for solid coolant, a funnel with a discharge valve, a loading funnel For fuel, the outlet end of which is located in the funnel of the valve for unloading, and a mixing zone with partitions located under the valve for unloading, the valve of the fuel hopper located in the loading funnel of the heating chamber and installed with a valve for unloading the heating chamber on a common vertical stem equipped with a spring , with the possibility of their simultaneous vertical movement, and the pyrolyzer is equipped with a stirrer and discharge pipe with a locking device, characterized in that, in order to prevent precipitation (condensation ) on the walls of the apparatus of the liquid pyrolysis products, after the experiment is completed and the apparatus is cooled, the heating chamber and the pyrolyzer are equipped with fittings for attaching them to the nitrogen tank in order to purge the apparatus with nitrogen. ! 2. The device according to claim 1, characterized in that, in order to ensure tight shutoff of the valves of the exhaust holes of the fuel hopper and the heating chamber of the solid coolant in the cold and hot state, the valve of the fuel hopper is equipped with an additional spring, which enables the vertical movement of pcs

Description

The thermal processing of solid fuels using new technologies for heating solid fuels with fuel has recently become more widespread in industry.

At the same time, an outdated technology continues to be used for preliminary testing of fuel and modeling the process of thermal decomposition of fuel, in which the test sample of solid fuel is heated not with a solid coolant - as in real technology, but through the wall - by placing the test sample of fuel in a vessel with outside walls .

Therefore, to obtain the initial characteristics of the process of thermal decomposition of fuel with heating with a solid heat carrier, necessary for the calculation and design of a similar technology, especially when involving new types of fuel in the processing, it is not enough to apply the most common traditional tested method for determining the characteristics of the process of thermal decomposition of solid fuel and the yield and composition products obtained using the so-called Fisher retort, in which the fuel is heated through Tenkai from an external heat source - by means of electrically heated coil (GOST 3168-93).

This technique does not take into account the specifics of thermal processing of fuel when it is heated by mixing with a hot solid coolant. It does not take into account such an important factor as a possible chemical

the interaction of solid coolant with fuel and with vapor-gas products of fuel decomposition.

An example of such an interaction is the interaction of calcium and magnesium carbonates contained in a solid heat carrier - shale ash, known from the theory and practice of thermal processing of shale with a solid coolant, with sulfur compounds contained in combined-gas products of shale decomposition, which affects the chemical composition of the shale process resin, significantly reducing its sulfur content, which is a harmful impurity that degrades the quality of the resin.

A well-known laboratory furnace for modeling the process of layer-by-layer coking, containing a coking chamber with heating walls, divided by partitions into sections with thermocouples (see RF patent No. 2105031, publ. 02.20.1998, CL. 1/10, AB 17/02).

The disadvantages of this device is that the heating of the test sample is carried out through the wall and does not take into account the specifics of thermal processing of fuel due to heating with a solid heat carrier. In addition, only the change in the coal mass without the removal of the gas mixture is studied.

In order to obtain the characteristics of the process of thermal decomposition of fuel, reflecting the process features associated with the use of solid coolant, a new methodology for testing the process of pyrolysis of solid fuels with heating of a solid fuel sample under study using a solid coolant is proposed in utility model patent No. 69862 (03.07.2007).

A device for simulating the process of semi-coking of solid fuel proposed in the aforementioned patent has the disadvantage that during cooling of the apparatus of the device after the experiment, deposition (condensation) can occur on the walls of the apparatus

liquid pyrolysis products - resins in the vapor-gas mixture of pyrolysis in the vapor state.

Such condensation will lead to a distortion of the measured yield of liquid pyrolysis products - one of the main measured indicators and to a possible violation of the normal operation of the apparatus of the device, due to the sticking of resin and solid fuel particles on the walls of the apparatus. The use of the device will be significantly more complicated, since after each test it will be necessary to clean the equipment using solvents.

The disadvantages of the prototype are also:

- rigid fastening of valves 3 and 9 to the stem 19, as a result of which, when the valves 3 and 9 are in a tight fit when cold, to the outlet openings (hopper 1 and heating chamber 5) that they overlap after the stem 19 is heated to a high temperature (600-700 ° C) between the valve 9 and the outlet of the chamber 5, a gap may occur that violates the tight shutoff of the outlet of the heating chamber 5; a gap between the valve 3 and the hopper funnel 1 is also possible;

- the lack of constant mixing of the pyrolyzable material in the pyrolyzer and, as a result, the possibility of uneven heating and, in particular, overheating of the wall layers of the fuel;

- the lack of a loading pipe at the fuel hopper 1, which complicates its loading and sealing (since it will be necessary to remove the hopper cover).

To ensure reliable operation of the device and to prevent the possible deposition of resin residues on the walls of the apparatus during their cooling after the experiments, it is necessary to ensure timely removal from the apparatus, before they are cooled, of the remnants of the vapor-gas mixture of pyrolysis containing pairs of resins.

To this end, it is proposed to equip the device with a purge system with hot inert gas, with which the remnants of the vapor-gas mixture are immediately displaced from the device’s apparatus immediately after the experiment.

To carry out such a purge, it is proposed, in accordance with FIG. 1, to improve the design of the prototype device (patent for utility model No. 69862 dated 07/03/2007) to provide a solid heating medium heating chamber 5 with a fitting 23 located in the upper part of the chamber 5, and a pyrolyzer 6 with a fitting 24 located at the bottom of the pyrolyzer 6, with the supply of inert gas through these fittings in the apparatus of the device.

At the same time, the fittings are connected via pipelines to a nitrogen cylinder equipped with a valve regulating the gas supply.

The fitting 23 is located in the upper part of the solid heat carrier heating chamber 5 to provide nitrogen purging of the entire volume of the chamber 5 — due to the nitrogen movement from top to bottom — towards the outlet pipe 15, and the fitting 24 is located in the lower part of the pyrolysis 6 to provide nitrogen purging the total volume of the pyrolyzer 6 ~ due to the movement of nitrogen from the bottom - up - towards the outlet pipe 15.

Reliable purging of apparatus devices, on the walls of which condensation of resins is possible (heater 5 and pyrolyzer 6), requires a small amount of purge gas - only several times the volume of these apparatuses.

Experience with the Fisher retort shows that to determine the yield of pyrolysis products — resin, pyrogenetic water, gas, and semicoke — it is sufficient to pyrolyze 50-100 g of the test fuel.

If you set the task of obtaining a significantly larger amount of resin - for its detailed study, then the amount of pyrolyzable

fuel will be 1 kg, and the amount of solid coolant, respectively, no more than 3-4 kg. Thus, the required volume of each of the apparatuses of the heating chamber and the pyrolyzer will be no more than 3-4 liters (with a bulk weight of fuel and coolant of the order of 1.2-1.5 kg / l), and for their purging with 3-4 times the volume of gas required about 15-20 liters of nitrogen.

Figure 1 shows a sketch of an improved device for modeling the process of semi-coking solid fuel.

The device comprises a fuel hopper 1 with a loading nozzle 21, an outlet nozzle of which closes a valve 3 provided with a spring 22. A vertical heating chamber 5 of a solid heat carrier and a pyrolyzer 6 coaxial with the chamber are placed underneath it in a two-section furnace 4 with electric heating. The heating chamber 5 of the solid coolant is equipped with a loading nozzle 7 for the solid coolant, a funnel 8 with a valve 9 for unloading the heated coolant. A funnel 10 is located under the hopper 1, with a tube 11, the output end of which is located in the funnel 8.

Under the chamber 5 there is provided a mixing zone 12 with partitions 13. located under the valve 9 for unloading. The heating chamber 5 and the pyrolyzer 6 are equipped with thermocouples 14. A pipe is provided for outputting steam and gas products 15, a mixer 16 with a mechanical drive 25 and a discharge pipe 17 with a shut-off device 18. The valve 3 of the hopper 1 is located in the feed funnel 10 for supplying fuel to the heating chamber 5. The valve 9 of the heating chamber 5 and the valve 3 of the hopper 1 are mounted on a common vertical rod 19, equipped with springs 20 and 22 with the possibility of simultaneous vertical movement of both valves.

To eliminate the second drawback of the prototype noted above - the possibility of loosening of the valves 3 and 9 to the holes they overlap due to the formation of a gap between the valves

and outlet openings (due to the temperature extension of the stem 19), it is proposed to install a valve 3, which closes the outlet of the hopper 1, on a spring 22 attached to the stem 19, which allows additional movement of the rod 19 and valve 9 from the bottom up under the influence of the spring 20, due to which selects the gap between the valve 9 and the outlet of the heating chamber 5.

To eliminate the third drawback of the prototype and prevent possible uneven heating of the fuel in the pyrolyzer and, in particular, overheating of the wall layers of fuel due to contact with the walls of the pyrolyzer heated externally, a mechanical stirrer 16 with an electric drive 25 is provided for continuous mixing of the fuel in the pyrolyzer with a small number of revolutions (1-2 rpm).

The device operates as follows.

In the heating chamber 5, when the valve is closed, 9 solid coolant is loaded, in an amount 3-4 times the mass of fuel. Then, sections of the furnace 4 are turned on and the heat carrier is heated in the heating chamber 5 to a predetermined temperature (600-700 ° C) and the pyrolyzer 6 is heated to the calculated process temperature (450-550 ° C). The furnace 4 is equipped with means for controlling and regulating the temperature. After that, the test fuel is loaded into the hopper 1 with the valve 3 closed. Then, using the rod 19, at the same time, valves 3 and 9 are opened for supplying fuel and coolant through the mixing zone 12 to the pyrolyzer 6, which is preheated to a predetermined pyrolysis temperature. The mixture of fuel and coolant is kept in the pyrolyzer 6 for a predetermined time, with constant slow stirring (1-2 rpm), during which the thermal decomposition of the fuel occurs, and the resulting vapor-gas products through the outlet

the pipe 15 is sent to the condensation compartment (not indicated in FIG. 1).

The purge gas supply should be started after completion of the ASG outlet, which can be determined by the readings of the gas flow meter installed at the outlet of the condensation system.

Throughout the entire decomposition of the heated fuel sample and until the gas evolution is practically stopped, the temperature in the pyrolyzer should be maintained at a predetermined level, and heating will be turned off after nitrogen purging is completed.

The purge gas is supplied to the hot equipment, so the supplied gas will be heated from the walls of the apparatus and its preheating is not required.

The flow rate of nitrogen must be adjusted according to the gas meter of the condensation system using a valve on the cylinder.

The temperature in the apparatus will decrease slightly after nitrogen is supplied, as will be seen from the readings of thermocouple temperature measuring instruments 14.

After the process of purging the equipment with nitrogen is completed, the pyrolyzer is unloaded through the discharge pipe 17. If necessary, use a mixer 16.

DEVICE FOR MODELING PROCESSES OF THERMAL PROCESSING OF SOLID FUELS

LIST OF APPARATUS AND NODES

1. Fuel hopper

2. Hopper outlet

3. Hopper valve

4. Two-section electric furnace

5. A chamber for heating a solid heat carrier

6. Pyrolyzer

7. Loading branch pipe

8. Funnel of the heating chamber

9. Valve of the heating chamber

10. Loading funnel

11. The fuel supply pipe for mixing with the coolant

12. The mixing zone

13. Partitions

14. Thermocouples

15. Outlet pipe for combined-cycle pyrolysis products

16. Stirrer

17. The discharge pipe of the pyrolyzer

18. Locking device

19. Valve stem

20. Stem spring

21. The loading port of the fuel hopper

22. Valve spring 3.

23. 24. Nitrogen nozzles

25. Mechanical drive of the mixer

Claims (4)

1. A device for simulating the process of semi-coking of solid fuel, including a sealed pyrolyzer placed in an electric heating furnace and equipped with thermocouples and steam and gas products, a fuel hopper equipped with an outlet pipe with a valve, a vertical solid heating chamber equipped with thermocouples mounted on a pyrolyzer, placed in a furnace with electric heating and equipped with a loading nozzle for solid coolant, a funnel with a discharge valve, a loading funnel For fuel, the outlet end of which is located in the funnel of the valve for unloading, and a mixing zone with partitions located under the valve for unloading, the valve of the fuel hopper located in the loading funnel of the heating chamber and installed with a valve for unloading the heating chamber on a common vertical stem equipped with a spring , with the possibility of their simultaneous vertical movement, and the pyrolyzer is equipped with a stirrer and discharge pipe with a locking device, characterized in that, in order to prevent precipitation (condensation ) on the walls of the apparatus of the liquid pyrolysis products, after the experiment is completed and the apparatus is cooled, the heating chamber and the pyrolyzer are equipped with fittings for attaching them to the nitrogen tank in order to purge the apparatus with nitrogen. 2. The device according to claim 1, characterized in that, in order to ensure tight shutoff of the valves of the exhaust holes of the fuel hopper and the heating chamber of the solid coolant in the cold and hot state, the fuel hopper valve is equipped with an additional spring, which enables vertical movement of the rod 19 and valve 9 from bottom to top with thermal extension of the rod 19. 3. The device according to claims 1 and 2, characterized in that, in order to ensure uniform heating of the entire mass of fuel in the pyrolyzer and to prevent overheating of the fuel layers adjacent to the walls of the pyrolyzer, the agitator located inside the pyrolyzer is provided with a mechanical drive and provide continuous mixing of the fuel for all experience. 4. The device according to claims 1 and 2, characterized in that, in order to ensure the tightness of the device and simplify its operation, the fuel hopper is equipped with a loading nozzle with a sealed cover.