SU1071232A3 - Method for utilizing secondary heat from batch pulp cooking plant - Google Patents

Description

This invention relates to methods for utilizing the waste heat of plants for periodic pulping. There is a known method of utilization of the secondary heat of the installation, periodic pulping, which includes steam trapping in final blows, ott pulp pulp from a vertical digester, from the leveling reservoir under pressure to collect the spent liquor from the boil and using trapped steam in the cooking process, processes in units of heat flj. The known method is characterized by low efficiency of the process. The goal is achieved by the fact that in the method of recycling secondary heat from a plant for periodic pulping, including trapping steam from final blows, from pulp from a vertical cooker, from a pressurized leveling tank to collect spent liquors after cooking and using it steam in the cooking process, in auxiliary processes, in heat recovery aggregates, part of the steam is separated from the leveling tank and directed, under control of the pulp blowing, from digester FIG. 1 shows an installation diagram for implementing the method; in fig. 2 is a diagram of the proposed process. The installation includes cookers 1 (8-12 pieces). The circulating heating 1 is provided by a heat exchanger 2, equipped with a circulating pump 3. The external steam is supplied to the heat exchanger 2 through conduit 4. The circulating cooking liquor is returned to the welding apparatus 1 via conduit 5 with valve 6. By means of pipeline 7 with valve 8 piping. It is leveled by a reservoir 9 connected via pipe 10 to the valve 11 of the cooking appliance 1. The cooking apparatus is connected to the pipe 12 by means of the blow tank (not shown) with the valve 13. The pipe is 10 soy House 14 with a valve 15 for supplying fresh cooking solution, and a pipe wire 16 with a valve 17 through a circulation pipe with heat exchanger 2 and a bottom screen of the cooking apparatus 1. The bottom of the leveling tank 9 is connected by pipe 18, part through pipe 19 with an evaporation cyclone 20 and partially through a pipeline of 21 g from the evaporation cyclone 22. The bottom of the evaporation cyclone 20 through pipe 23 is connected to the evaporation cyclone 22, and its steam outlet through pipe 24 to the steam pipe 25, directed from the top of the cooking device arata 1. Pipelines 24 and 25 are connected to other cooking devices (tie shown). The vapor outlet of the evaporative cyclone 22 is connected via pipe 26 to pipe 27, which is directed from the upper part of the cooking apparatus 1 and is equipped with a valve 28. Pipeline 27 is connected to a heat recovery unit 29, from which evil gases enter the main pipe 30. Liquid evaporative cyclone outlet 22 connected by pipeline 31 to the black liquor tank. The upper part of the equalization tank 9 by pipe 32 with valve 33 is connected to the upper part of the cooking apparatus 1, which through valve 34 is connected to pipe 27. Pipe 35 from valve 36 is connected to pipe 16. Pipe 19 is provided with valve 37, Tiiy6o 23 - valve 38, pipeline 21 - by valve 39, and pipeline 32 - by valve 40. The installation works as follows. Chip loading (line AB in Fig. 2) begins by opening the valve of the cooking apparatus 1 and feeding the chips. Fresh and secondary steam from conduit 24 is fed to the chip filler. When the corresponding chip level is established in the cooker 1, the valves are closed. Steam purging of chips (line C-C) is performed by adding steam, steam from the evaporating cyclone 20 through valve 40. At the same time, air is blown into the cooking apparatus 1 through valve 36 in the pipeline 35. Preheating with vapor from the evaporative cyclone 20 continues until reaching a predetermined temperature or pressure in the cooker 1, after which the valve 40 in the pipeline closes with the cooker and the cyclone. With the help of temperature control means, the exhaust valve 36 is closed when the steam flow reaches the recording point of the control system in the pipeline (range -35. The cooking solution (Pini C-D) enters the cooking apparatus 1 through the lower sieve. To increase the feed rate, it can also supplied through a medium sieve. The supply of the black tree can be increased through conduit 10 by adjusting the flow from the evaporation tank 9 to the brewer, thus saving fresh steam. When the conduits 10 and 14 are supplied The quantity of the solution is sufficient, the valves 11,15 and 17 are closed. Then the circulation pump 3 for the cooking solution (line D-E) is turned on. Indirect heating of the cooking solution; the solution with fresh steam is started using temperature control means that record its temperature at the heat exchanger's outlet. 2 At the same time, valve b is open and 8 is closed. At the same time, fresh steam is supplied to the cooking apparatus from line 24 through valve 40. Supply is stopped automatically when the pressure in the cooking apparatus 1 rises, approximately to the pressure in the evaporator cyclone. The inert gases, which follow the expanded steam from the pipe 24 to the cooking appliance 1, are removed from it through the degassing pipe of the turpentine oil, which, during heating, is opened to some extent. Then, heating (line EF) to the boiling point is performed indirectly in heat exchanger 2 using fresh steam, after which cooking (line P-6) occurs and unloading (line GH) of free cooking solution (part of it is in chips) from the cooker time of the cooking period using the circulation pump 3. The valve b in the circulation pipe for the cooking solution is closed, and the valve in the pipe from the heat exchanger 2c makes the leveling tank 9 for the cooking solution and the valve 17 on the suction side of the pump 3 by opening. The unloading stops automatically when the level inductor, located at the appropriate level in the cooker, closes the valve 8 in the pipe conduit to the leveling tank 9 and turns off the circulation pump ... ... The pressure in the cooker 1, Plini HI) decreases the opening of the valve 40 in the pipe 25 and the cooking apparatus 1 into the pipe The steam valve 40 is controlled by a pressure regulator which closes the valve 37 in the pipe to supply liquid from the leveling tank 9 to the cyclone 20 to compensate for peak load caused by steam from the cooker 1. .... When the pressure in the cooker (line 1-J) drops to a value close to the pressure in the cyclone 20, the valve 40 in the pipe 25 from the cooker 1 automatically overlaps and liquid is again supplied to cyclone 20 from leveling tank 9. Then pressure in cooking appliance 1 is reduced due to degassing through valve 28 to heat recovery unit to produce hot water. Change load-and degassing out. The cooker 1 is measured by a flow meter. the pipe unit 27, while its oscillations are compensated for by regulating the flow of liquid in the evaporation cyclone 22 by means of valve 39. The liquid turns into such a quantity of steam that the sum of its flows in pipelines 26 TL 27 becomes constant. The steam flow in the heat recovery units to produce hot water is measured by a flow meter. If the throttling of the valve 39 is not enough, then the valve 28 is throttled to obtain a constant amount of flows directed to the unit. If there is a shortage of time, degassing can be carried out simultaneously through valves 28 and 40. Then the valve is regulated by pressure in line 24. Valve 28 controls the required amount of flows in lines 26 and 27. During degassing (line 3-K), the flushing liquid (filtrate from washing apparatus) is fed into the cooking appliance 1 through valve 15 (valve 17 is closed) by the pump through the lower sieve and the flow is regulated by a level control set at an appropriate level. Valves 34 and 28 in the degassing pipe to the heat recovery unit are also shut off. The pressure is supplied to the cooker 1 (line K-and by opening valve 33 to the leveling reservoir P of the cooking solution. Contents. Of the cooker is blown into the blow tank (line L-M). When all the contents are blown out, valves 13 and 33 in the purge The pipe and pipe from the leveling tank 9 are automatically closed. The cooker 1 is degassed again (line M -N) Bv - arperaT heat recovery using valve 28. When the pressure is set in the cooker, the lid opens and it is ready for a new one} Hickle The evaporator cyclone 20 is an integral part of the cooking system, which allows the return of degassed vapors and compensates for the immediate degassing and heat demand of the cooking apparatus 1.

The outgoing energy flows from the main system are measured by three flow meters (installed in the pipeline 23,26 and 27. The flow data is fed to the control system

through valve 39 through degassing valves 28 and 34.

Thus, the proposed method provides the efficiency of utilization of secondary heat.

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Claims (1)

^! (5 7) METHOD FOR SECONDARY HEAT DISPOSAL 'INSTALLATION OF PERIODIC CELLULOSE BREWING, including the capture of steam * from the final blow-offs, from cellulose blowing from a vertical digester, from a pressurized leveling tank · to collect spent liquor after cooking and cooking waste process, in auxiliary processes, in heat recovery units, I distinguish *; that is, in order to increase the efficiency of the process, a part of the steam is separated from the leveling tank and directed along control. for blowing pulp from the cooking! boiler.