UA144250U - METHOD OF CONTROL OF THE PROCESS OF DRYING OF GRANULAR TECHNICAL CARBON IN DRUM DRYING INSTALLATIONS - Google Patents

Abstract

The method of controlling the drying of granular carbon black in drum dryers includes dosing pulverized carbon black from the equalizing tank through the sluice gate to the granulator, mixing with water-molasses solution and the formation of wet granules entering the drying drum drying under the influence of thermal energy from the furnace burners, removal of the steam-gas mixture by the compressor through the channel in the outlet end of the drum, unloading of dried carbon granules through the sluice gate to the transport and cooling conveyor. Additionally calculate the weight and humidity of the product on individual sections of the drying drum on the basis of indirect measurements and the application of a computational process model, control the burner performance of each zone is carried out using zone regulators based on weighted misalignment the component of the regulator of the end zone is determined by calculating the derivative temperature of the vapor-gas mixture multiplied by the coefficient of the differential link.

Description

The useful model belongs to the automation of chemical-technological processes and can be used during the control of the drying process of granular technical carbon in drying plants in which the drum rotates inside the furnace with gas or liquid fuel burners.

There is a known method of controlling the drying process using feedback on the temperature in the upper part of the furnace to regulate the productivity of the burners in the initial and middle parts of the drum and feedback on the temperature of the steam-gas mixture at the exit of the drum to regulate the productivity of the burners in the final zone.

The disadvantage of this method is the inability to automatically determine the correct temperature settings for the regulators of each zone. This is due to the lack of a direct connection between the temperature of the flue gases and the temperature of the steam-gas mixture and the humidity of the initial product. This method requires the operational staff to make subjective decisions regarding the selection of temperature settings and their changes in the process of forming a stable mode of operation of the technological line. With existing technical means, it is impossible to take into account the following factors that influence the course of the drying process: kinetic properties of moisture evaporation for the current brand of technical carbon; loading each conventional zone of the drum with technical carbon; calorific value of the flame of the burners; the initial average moisture content of the product upon entering each conditional zone of the drying drum.

This method is accepted as the closest analogue.

The basis of the useful model is the task of developing a method of controlling the drying of granulated carbon black in drum dryers and stabilizing the initial moisture content of the product at the level of 0.2-0.9 96 by influencing the performance of furnace burners.

The task is solved by proposing a method of controlling the performance of furnace burners, in which the weight and moisture content of the product in individual sections of the drying drum are additionally calculated on the basis of indirect measurements and the application of a computational model of the process, control of the performance of the burners of each zone with the help of zone regulators on the basis of weighted reconciliation according to three control points between the desired humidity values and the identified model values, additionally the differential component of the final zone regulator is determined by calculating the temperature derivative

From the steam-gas mixture multiplied by the coefficient of the differential link.

The technological line of wet granulation and drying consists of a storage tank, a granulator, a drying drum that rotates inside the furnace, a system for transporting and cooling dry granulated carbon, an aspiration and dust collection system, furnace burners that are distributed along the furnace, and a storage tank for the finished product.

The process begins with the dosing of pulverized technical carbon from the storage tank to the granulator. The formation of wet granules occurs in the granulator by intensive mixing of powdered carbon with a water-molasses solution. After wet granulation, carbon enters the drying drum from the end loading channel. The drying of granular carbon black takes place during its advancement along the drying drum, which is installed at an angle and rotates at a speed of 2-3.5 rpm. Shelves are mounted inside, which ensure mixing of granules and uniform evaporation of moisture from the mass of the product. The main source of thermal energy is the furnace burners, which form flame torches in the lower part of the furnace. Thermal energy is transferred to the walls of the drum through radiation and direct heat transfer. All the moisture that evaporates from the granules, as well as the powdered carbon from the destroyed granules, is removed by the aspiration system through the end channel on the output side of the drum. Dry granules are discharged from the output side of the drum and enter the transport-cooling system.

The initial humidity of the product is 50-52 95, the humidity of the finished product should be within 0.2-0.8 95. As a result of variable granulation modes, variable drum load, work with different brands of technical carbon, changes in air parameters and burner combustion modes, humidity fluctuations are observed of the original product. A significant influence of the initial conditions (such as the temperature of the input technical carbon, the temperature of the water-molasses solution, the initial humidity) on the course of the drying process is observed. The multitude of control channels requires their coordination and dispatch during the formation of control influences.

The implementation of the control method begins with the determination of the desired trajectory (Fig. 1) of the change in the moisture content of the product as a function of the length of the drum and as a function of the time of advancement of a conditional portion of the product along the drying drum. Along its length, the drum is divided into 7 conventional sections: 1.1 and 1.2 - the first third of the drum, which rotates inside the furnace; 2.1 and 2.2 - the middle third of the drum 60 rotating inside the furnace; 3.1 and 3.2 - the last third of the drum; 4.1 - drum unloading area. This allows you to simplify model calculations and structure the process of automatic control.

The main initial phase variable of the process is humidity. Expression (1) defines the transmission link, which describes the dynamics of changes in the moisture content of a conditional portion of the product in time from the time it flows into the bulk burners of one conditional zone: 45057 4600541. (1)

In addition, the overall quality of the process is affected by fuel consumption and the smoothness of moisture evaporation. The classic quality criterion, which can formally describe the proposed conditions for the process, has a superficial appearance. 2 2 on ee still with? dk and y (2) where Io, Iyyk - respectively, the initial and final moments of the passage of a conditional portion of the product through the drying drum; 9, 92 - weighting factors that determine the degree of influence of the relevant components on the final value of the criterion; U. controlled variable (humidity) (953; CH - controlling influence (fuel consumption) (m/s).

The first term in the integral function regulates the minimum absolute humidity deviation, the second - the maximum smoothness of the transition process (minimum derivative humidity), the third - the minimum control influence (fuel consumption). The presence of the second term is justified by the fact that a too rapid drop in humidity is not realized and is undesirable, as the percentage of overdried granules increases, which leads to their destruction or sintering and complicates the management process. Coefficients 9 Che adjust the weights of the first two terms relative to the third, taking into account their importance and the used units of measurement.

Or terium; -

OV VV (92 more for » (3)

Expressions (1) and (3) define the law of optimal change of product humidity as a function of time. It is possible to scale this dependence taking into account the current angular velocity and obtain the law of the optimal change of humidity as a function of the length of the drum. In fig. 1 shows a possible view of the optimized trajectory, which allows you to determine the desired humidity values at individual points.

Next, the initial modes of operation of furnace burners are formed.

The following stages are performed cyclically.

Signals characterizing the operation of the technological flow are read: combustion air pressure, combustion air temperature, combustion air humidity, gas pressure, the degree of opening of the air and gas burner valves, consumption of powdered technical carbon and water-molasses solution in the granulator, temperature in separate zones of the furnace, the temperature of the steam-gas mixture removed from the drum, the temperature of the initial granulated technical carbon.

The amount of evaporated liquid on each section of the drum is calculated based on the proposed model (Fig. 2). The reset signal of the integrator is calculated based on the speed of rotation of the drum and the time of finding a conditional portion of the product on a separate section of the drum.

Next, based on the simulation model (Fig. 3), the advancement of portions of the product along the drum, the weight of the material and the amount of evaporated moisture are calculated.

The discrepancy between the optimal and actual drying phase trajectories is calculated.

The humidity adjustment for each zone is calculated based on three points. The method of regulating fuel and air consumption can be illustrated in fig. 4. For each zone, it is possible to determine C characteristic points - the moisture content of the material at the entrance to the zone, the moisture content of the material in the middle of the zone, the moisture content of the material at the end of the zone.

The following input signals can be selected for the humidity controller of the first zone: - humidity of granulated technical carbon at the entrance to the drying drum; - moisture content of technical coal at the outlet of section 1.1; - moisture content of technical coal at the outlet of section 1.2; - the initial moisture content of technical carbon, which was specified during the search for the optimal trajectory; - desired humidity at the exit of section 1.1;

- the desired humidity at the exit of section 1.2.

The following input signals can be selected for the humidity controller of the second zone: - the humidity of granulated technical carbon at the entrance of section 2.1, which is equal to the humidity at the exit of section 1.2; - moisture content of technical coal at the outlet of section 2.1; - moisture content of technical coal at the exit of section 2.2; - desired humidity at the exit of section 1.2; - desired humidity at the exit of section 2.1; - desired humidity at the exit of section 2.2.

The following input signals can be selected for the humidity controller of the third zone: - the humidity of granulated technical carbon at the entrance of section 3.1, which is equal to the humidity at the exit of section 2.2; - moisture content of technical coal at the exit of section 3.1; - moisture content of technical coal at the outlet of section 3.2; - desired humidity at the exit of section 3.1; - humidity, temperature of the initial product; - desired humidity at the exit of section 3.2; - desired humidity/temperature of the initial product; - rate of temperature change of the steam-gas mixture.

Thus, it is possible for each zone to calculate three values of humidity mismatch (for the entrance to the zone, inside the zone, at the exit of the zone): ato - yo - Yad siya, - o (4) to - 2nd de her ! OR. values of desired and current humidity, respectively.

For each regulator, the final reconciliation can be calculated using the following odds: od ag "ОЙ; az yo (in) de 1, 82, 83 . weighting factors that allow you to calculate a weighted average

Out of disagreement.

The weighting factors are determined by the eupiric method based on model experiments.

The following values are offered: 91 7 9. a2 5 M. az,

The structural diagrams of the regulators are shown in fig. 4. Block 1 sets the desired trajectory of humidity changes in the drum zones, block 2 calculates the actual humidity based on the computational model of the process (Fig. 3). Block C performs the calculation of mismatch according to formulas (4), (5). Block 4 performs the calculation of the control influence according to the PID regulation algorithm. Block 6 corresponds to the control and management system of the furnace burner of each zone, element 7 - the corresponding furnace burner. Block 8 calculates the effective performance of the burner to identify the weight of moisture evaporated in the area of the drying drum.

The outputs of the PID controllers set the consumption of hydrocarbon fuel. The burner control system ensures appropriate fuel supply and fuel-air ratio.

It should be noted that for the third zone there is an additional informational parameter - the temperature of the steam-gas mixture, which is indirectly related to the temperature and humidity of the technical carbon at the exit of the drum. The derivative of the temperature of the mixture directly corresponds to the derivative of the technical carbon temperature, which is related to the moisture content of the finished product. It is proposed to modify the PI controller of the third zone in such a way that the differential component is calculated not on the basis of the derivative of the humidity mismatch signal, but on the basis of the derivative of the temperature of the steam-gas mixture. Block 5 (Fig. 4) multiplies the derivative temperature signal by the coefficient of the differential link.

Alternate regulation of the performance of furnace burners is carried out starting from the third conditional zone of the furnace.

Periodically, the results of model calculations of the state of the product are refined according to the signals of the actual temperature of the initial technical carbon, the rate of change of the temperature of the steam-gas mixture.

After performing a full adjustment cycle for three conditional zones, a cyclical repetition of actions is performed, starting with the reading of signals characterizing the operation of the technological flow and calculation of the amount of evaporated liquid.

List of drawing figures: fig. 1 - An example of an optimized phase trajectory of humidity changes as a function of time. fig. 2 - Scheme for calculating the weight of evaporated moisture on a separate section of the drying drum. fig. 3 - Scheme for calculating the advancement of portions of the product along the drum, the weight of the material and the amount of evaporated moisture. fig. 4 - Block diagram of the calculation of control influences for the implementation of the method of controlling the drying process of granular technical carbon. fig. 5 - Time diagram of the process of stabilization of technical carbon humidity at the exit of section 1.2 of the drying drum.

Transient processes of humidity regulation in separate areas (Fig. 5) confirm the efficiency of the proposed control method in the event of disturbing influences and the stability of transient processes.

As a result, there is a decrease in material and energy costs per unit of production, including due to a decrease in the amount of non-standard granular carbon in the drying process, a decrease in fuel consumption, a decrease in the level of manual labor and subjectivity in the formation of equipment operation modes by determining the actual controlling influences on furnace burners and stabilization of the humidity of the original product.

Claims (2)

USEFUL MODEL FORMULA A method of controlling the drying of granulated carbon black in drum dryers, which includes the dosing of pulverized carbon black from the equalization tank through the sluice gate to the granulator, mixing with the water-molasses solution and forming wet granules that enter the drying drum, advancing the granules along the drum , which rotates, and drying under the influence of thermal energy from furnace burners, removal of the steam-gas mixture by the compressor through a channel at the outlet end of the drum, unloading of dried carbon granules through a sluice gate to a transport-cooling conveyor, which is distinguished by the fact that the weight and moisture content of the product are additionally calculated on in separate sections of the drying drum based on indirect measurements and the application of a computational model of the process, control of the performance of the burners of each zone is carried out with the help of zone regulators on the basis of weighted discord at three control points between the desired values humidity readings and identified model values, additionally the differential component of the final zone regulator is determined by calculating the derivative temperature of the steam-gas mixture multiplied by the coefficient of the differential link. Humidity, 5 nn p cha v- sweat week nn in nn per pound min PO o nn: p nn NI a 25a 5 750 me what zo Time, is Fig. 1 Costs of coal-fired fuel s tt panna Calorific value of coal-fired fuel and fuel that Compressed air costs dH 000000 I Weight of vaporized moisture Air temperature | E Integrator - , . І Block of calculation chn Air humidity speed І evaporation Temperature of technical moisture on a separate: 0 BEJUІ Сумііни пев ці ІІНЖ СУПІІІ ІІІІІІ ІК ІК signal: below | drum Temperature of the corresponding I ! with. chartyans topha Initial temperature on nVOoluktu nin Naga hekhvurletsu | E Weight of moisture " Fig. 2 ! , sawdust cotton wool per section. 1.2 vir Integrator 7 Memory nn you VNU yaki. more technical coal | mice! we HE NOT M mix) and and | The weight of the TV on the same Saignai i inc. in NW reset Signal | The weight is like the weight of the integrator ABVINTYAZENIA! product |. Product details Instant withdrawals. 1.1 | | hope 1.th consumption of water- zntet: BO ee orla M and integrator che Memory Zh U. i zh-U PI melosovogo integrator and momya and nene Five s M (5 solution (kg/s) saanot 000030 Vainelegy narid and Weight of roasted food and moisture per section 1.1. 2 Weight of dusty TV per day. 41 Weight of evaporated moisture per part. 4.1 "OO | 0 Moisture at the outlet of part. 1 Current НА o What the signal generator is speeding up 0 (loading information) current rotation of jar rpm - drum (rpm) Signals for loading data to memory elements and monitoring integrators Fig. WITH E NO Initial humidity set! And Ts | keneoriv shchi | | The specified humidity zh NI nn! juices 1.1 schi SHE | | The specified moisture content of zlptooni 12 no more ii. ' - Zones 2.1 Ше -ю Signals ше | | | of sensors i) 50071 Set humidity si esh and zhizones 5.2 мя и 5 7 и ой Set humidity В ! zones 3.1 and the given humidity of it! | zone 3.1 still shk: shk : ptn " | re Signals and and and shi - | | ! thing Z Set humidity ! -th rent KE OKi zones 3.5 and ! | SHO. ! rya - set | | 6 SH what: ! humidity | е | ші ше ші ше | и шк - 1, -Я Ж product ' Ta Z M ! ШЮ ше) and ш- Temperature of the steam - gas sum of the current parameters of the technological flow Fig. 4 In KO and ! tires of the sknodavvmu: dossier press tires SHY and » peles y szhnizhksk zov e ve SHE S Y: ; Di N Z and I! ; N Z i: Z V kh chuk x i N: N N x y Z Z i i: I i SPE I title via znzi innnn znih signs zny news zny py nnvnn znysh schu yi gi N N N N Yan N | N ! dk Ba 5 1 and ! N E ia : N : and EN SCHE | and Z E N Z i : ve 5 VO re en nn p v p p p p p o 5: D E | | : | ! ! And her ShK ennnki zvv vnih knkninnn now known an an 7 Her 7th MN : : : risnyu N i : in those i ! With H and | E and I, In the village 5 y eh zny zny baths he minya mn We zno nn nn pen nn min sho zho. | : Н Н : и и и : он щи и ни выни Вых вын КВН ВЩ Мы не M в: pchyadnnnt en tnchn chatah annkunschymn ktkntcinnh et phonetic oVkktsn svoy i a i i i : N i zva N A i N i VE. schi To ODNYNY again WE MNN: DYNY, Ts UDOONYMny nie NNninnko Chin v En s o V p ZA es zv, Kn Ko z i 5 ha ; ZOOOo in ooo and Zoo A o ion Zodiac, An o nn years E schi in t Zk Kos, cha what still kyu still ze zak ee Time, s