RU2755647C1 - Method for selecting electricity from linear part of inductive-resistive, inductive and resistive electric heating systems and node for implementing method (options) - Google Patents

Abstract

FIELD: industrial heating.

SUBSTANCE: group of inventions relates to devices for heating sources of additional heat losses of industrial facilities. According to the first option, two connecting elements are installed on the heating conductor of the electric heating system at a certain distance from each other. In each of them, a heating conductor is spliced through a branching connector. An insulated electric wire is connected to the branched end of the connector, by means of which the electric potential is removed and brought into the power supply and control device of the heating element or the actuator drive. The heating element or the actuator drive is also connected to the power supply and control device. According to the second option, at the end of the heating line, a power supply and control device is installed for communication modules with monitoring and/or control devices, and/or control of a heated industrial object, at a certain distance from which a connecting element is installed on the heating conductor. The heating conductor is spliced through a branching connector. An insulated electrical wire is connected to the branched end of the connector, by means of which the electric potential is removed. The other potential is removed directly in the power supply and control device at the connection point of the phase conductor with a grounded heating tube having zero potential, or at the connection point of three-phase conductors at one point.

EFFECT: provision of power to the heating elements of sources of additional heat losses and other equipment without building an accompanying network.

10 cl, 10 dwg

Description

The invention is intended for heating sources of additional heat losses (valves, filters, valves, tees - pipeline branch points) of industrial facilities, such as tanks, tanks, pipelines, for powering actuator drives, as well as controls, monitoring and other equipment without building an accompanying networks.

For heating industrial pipelines of a large length, the use of resistive, resistive-inductive and inductive electric heating systems is well known (for example, the IRSN-15000 system based on the skin effect, the Internet page https://sstprom.ru/products/skin_system/). All of them operate on alternating current and, as a rule, at high voltage (above 1000 V). The main advantage of such systems is that they can heat long pipe sections from a single feed point. However, these systems have a significant drawback - it is the impossibility of heating sources of additional heat losses, such as valves, filters, valves, tees (pipeline branch points), which can occur throughout the entire linear part of the heated object. These elements have a higher metal content than the linear part of the pipeline, therefore, they require a large compensation for heat losses. The specified electrical heating systems are designed to compensate for heat losses of only the linear part.

A known system of electric heating of a pipeline (patent RU2727717, IPC F16L 53/35, publ. 23.07.2020), containing a pipe and thermal insulation around it, includes a supply transformer, supply boxes, end boxes, service boxes located between the supply and end boxes , medium voltage couplings and terminations, control and monitoring system of parameters, three heating resistive cables connected to three phases of a three-phase power system. Each resistive cable is housed inside a separately located guide element, which is fixed directly to the outside of the pipe under its thermal insulation. The shields of each resistive cable have intermediate and terminal grounds, and are also interconnected at the ends of the pipeline.

The known system is not intended for heating sources of additional heat losses (valves, filters, valves, tees - pipe branches).

The technical problem solved by the invention is the heating of sources of additional heat losses of industrial facilities, as well as the supply of power to the controls, monitoring and other equipment, without building an accompanying network.

The technical result is the provision of power supply to the heating elements of sources of additional heat losses of industrial facilities or actuators, controls, monitoring and other equipment, without building an accompanying network.

The problem is solved, and the technical result is achieved by the method of taking electricity from the linear part of the electric heating system of an industrial facility, which is carried out in two versions.

According to the first variant, the method of taking electricity from the linear part of the electric heating system of an industrial facility consists in the fact that two connecting elements are installed on the heating conductor of the electric heating system at a certain distance from each other, in each of which the heating conductor is spliced through a branching connector, and to the branched end of the connector connect an insulated electrical wire of the corresponding voltage class, by means of which the electric potential is removed and introduced into the power supply and control device for the heating element of the heat loss source or the actuator drive through the input corresponding to the installation zone of the heat loss source or the actuator, and the heating element of the heat loss source or drive the actuator is also connected to a power supply and control device.

According to the invention:

- as an electrical heating system, an inductive-resistive or inductive or resistive system is used;

- a junction box is used as a connecting element;

- a branching sleeve is used as a branching connector, which consists of a branching sleeve and an insulating material with an appropriate insulation class and ensuring tightness;

- as a power supply and control device, a box or control cabinet is used, containing a step-up transformer, a power supply, a residual current device, start-up circuit breakers, overvoltage limiters.

According to the second version, the method of taking electricity from the linear part of the electric heating system of an industrial facility consists in the fact that at the end of the heating line, a power supply and control device for communication modules with monitoring and / or control devices and / or control of a heated industrial facility is installed, at a certain distance from which a connecting element is installed on the heating conductor of the electric heating system, in which the heating conductor is spliced through a branching connector, and an insulated electrical wire of the corresponding voltage class is connected to the branched end of the connector, by means of which the electrical potential is removed and introduced into the power and control device through an input corresponding to the zone of its installation , while the other potential is removed directly in the power supply and control device at the point of connection of the phase conductor with a grounded heating tube having a zero potential, in the case of an inductive-resistive with system, or at the point of connection of three-phase conductors at one point in the case of a resistive system.

According to the invention:

- as an electrical heating system, an inductive-resistive or inductive or resistive system is used;

- a junction box is used as a connecting element;

- a branching sleeve is used as a branching connector, which consists of a branching sleeve and an insulating material with an appropriate insulation class and ensuring tightness;

- as a power and control device, a box or control cabinet containing a voltage stabilizer, start-up circuit breakers, a residual current device, surge suppressors, a monitoring and control module, a modem for receiving / transmitting data from monitoring devices, control and management of a heated industrial facility is used.

The technical result is achieved due to the stated set of actions in view of the following.

Since with a change in the length of the heating line, the voltage changes, i.e. there is a voltage drop, then there will be a different voltage drop, i.e. there is a potential difference. Therefore, from the connecting elements (for example, couplings) installed on the heating element of the electric heating system (resistive, resistive-inductive, inductive) at a certain distance from each other, it is possible to remove the potential and bring the heat loss source into the control device of the heating element to power this element. Also, the potential can be removed from a connecting element (junction box with a branching sleeve) located at a certain distance from the power supply and control device, and in the device itself (for example, in the form of a control cabinet), installed at the end of the heating line, in which the potential tends to zero ... There will also be a potential difference between these points.

The essence of the invention is illustrated by illustrations, which show:

Figure 1 is a diagram of the application of the proposed method with the installation of equipment conditionally in the middle of the heating line of the induction-resistive electrical heating system (for powering the heating element of the heat loss source in the form of pipeline fittings, for example, filters, valves, valves, etc., found on a heated pipeline );

Figure 2 is a graph of the voltage drop in the conductor of the inductive-resistive system with the designation of the conditional place of potential removal - in the middle of the electric heating line;

Figure 3 is a schematic diagram of a power supply and control device for a heating element of a heat loss source or an actuator;

FIG. 4 - a typical heating scheme for pipeline fittings (filters, valves, gate valves, etc.) found on branch pipelines;

Figure 5 is a typical heating scheme of branch pipelines from the main heated pipeline;

Figure 6 is a typical control circuit of the actuator - the gate valve drive;

Fig. 7 shows a typical power supply diagram for monitoring, control and management modules of a heated object in the case of using the method and the node at the end of the heating line (second embodiment of the invention);

Fig. 8 shows a power supply and control device for monitoring, control and management modules of a heated industrial facility on an enlarged scale (second embodiment of the invention);

Figure 9 is a graph of the voltage drop in the conductor of the inductive-resistive system with the designation of the conditional place of potential removal - at the end of the electric heating line;

Figure 10 is a schematic diagram of a power supply and control device for monitoring, control and management modules of a heated industrial facility according to the second embodiment of the method.

The figures indicate:

1 - power supply and control device (a heating element of a heat loss source or a drive of actuators, or modules for communication with devices for monitoring, control and management of a heated industrial facility) - control cabinet;

2 - connecting element (box);

3 - branching connector (coupling);

4 - wire for potential removal;

5 - heating conductor of the electric heating system;

6 - heated industrial facility;

7 - source of heat losses;

8 - heating element of the heat loss source (for example, self-regulating heating cables, or constant power cables, self-limiting cables, zone cables, resistive and inductive elements and heating elements based on the skin effect);

9 - electric drive of the valve on the pipeline;

10 - wire used to remove the zero potential (according to the second variant of the method);

11 - wires powered as a result of potential removal (according to the second variant of the method);

12 - power supply unit (PSU);

13 - modem for receiving / transmitting data (for example, monitoring and control);

14 - data input module (MVD) from external devices (for example, monitoring and control);

15 - storage battery (joint stock bank);

OPN - overvoltage limiter;

QF - automatic switch (power circuits);

SF1 and SF2 - automatic switches (control circuits);

T - voltage transformer;

NSHU - control cabinet heater;

A0 - thermostat;

BP - power supply unit;

Joint stock bank - storage battery;

A1 - temperature controller (programmable logic controller);

A2 - data transmission modem;

FD - residual current device (RCD);

KM - power contactor;

KL - intermediate relay.

The essence of the invention is illustrated by examples of specific implementation of the method.

Example 1. Application of the method according to the first option for heating sources of additional heat losses - filters, valves, gate valves and other fittings.

On the section heated by the skin system of the pipeline (for example, in accordance with Fig. 1, 4 and 5), it is necessary to supply the load with a power of 4.5 kVA.

Calculation of heat losses from a heated pipeline is carried out in accordance with GOST 31610.30-2-2017 Appendix E, SP 41-103-2000 with certain conditions.

We assume that the required maintenance temperature is + 5 ° С on the heated pipeline, the pipeline is located in the open air. The calculation does not take into account additional heat losses from pipe fittings (valves, flanges, supports, etc.). Climatic parameters for a specific area are taken in accordance with SP 131.13330.2018.

In the example, a steel elevated pipeline with an outer diameter of 325mm and a wall thickness of 7mm is considered. This pipeline is located in a region with an air temperature of the coldest five-day period, minus 39 ° C, and a provision of 0.92. The thickness of the insulating layer is 75 mm with a thermal conductivity coefficient of 0.045 W / m ° C. The temperature for maintaining the heated pipeline is not less than + 5 ° С.

In accordance with the calculations performed in accordance with GOST 31610.30-2-2017 Appendix E based on the above data, heat losses from the heated pipeline are 32.27 W / m. To these heat losses, a power reserve factor of 10% is added (this reserve is determined by the customer's regulatory documents, or by the internal documents of the organization engaged in calculations). Total heat losses from a heated pipeline with a safety factor is 35.5 W / m. The linear active power allocated by the electric heating system must be at least 35.5 W / m in order to ensure the temperature of the heated pipeline at least + 5 ° С. Considering that the linear part of the inductive-resistive system has a power factor of at least 0.92, we determine the total linear power (Cosφ = Rud / Ssp. → Ssp. = Rud. / Cosφ = 35.5 / 0.92 = 38.6 VA / m). To take additional power to supply additional loads from the existing electric heating system and to maintain the temperature on the pipeline not lower than + 5 ° C, it is necessary to add the power of the additional load to the total power.

Suppose the additional load that needs to be supplied from the existing system is 4500VA. We will take additional power from the existing system at a site of 260 meters (this distance is determined by the design documentation and may vary depending on the power of the system and on the load power). Dividing the power of the additional load by the length of the section, we obtain the value of the linear power, which must be added to the power of the system (S / L = Ssp. 4500/260 = 17.3 VA / m). So, the total power of the system, taking into account the additional load, will be 38.6 + 17.3 = 55.9 VA / m.

Knowing the required linear power of the system 55.9 VA / m, the cross-section of the current-carrying conductor is 15 mm ² , the parameters of the heater pipe 32x3 GOST 8734-75, GOST 8733-74, the main electrical parameters of the system are calculated, such as current and voltage (in accordance with the textbook " Design and operation of electrical heating systems in the oil and gas industry "/ ML Strupinsky, NN Khrenkov, AB Kuvaldin. Chapter 6. Electrical heating systems based on induction-resistive heating (skin systems)). The current will be 113 A. Knowing the current, we determine the voltage drop (V / m):

Ssp. = Usp. I → Usp. = Ssp. / I = 55.9 / 113 = 0.494 V / m

On an area of 260 meters, with a voltage drop in the conductor of 0.494 V / m, the potential difference will be 260 * 0.494 = 128.4 V. This voltage is fed into control cabinet 1, to increase the voltage to the standard value of 220V, a step-up transformer is installed in the control cabinet.

From this control cabinet it is possible to supply an additional 4500VA load without harming the heating of the main pipeline.

Thus, at a distance of 260 meters from each other, junction boxes 2 with branching couplings 3 are installed, with the help of which branching by wires 4 is performed. conductor through the branching connector (sleeve) 3. To the branched end of the connector 3 is connected to the potential removal conductor 4, which exits through a special sealing hole of box 2 and is inserted into the power and control device 1. The branching connector itself is insulated with a dielectric material. Branch sleeve 3 consists of a branch sleeve (crimp or with shear bolts) and insulating material (heat-shrinkable sleeve, or a set of special insulating tapes and heat-shrinkable sleeve) with the appropriate class of insulation and ensuring tightness.

All the necessary electrical equipment is placed in the control cabinet 1 according to the schematic diagram (Fig. 3) for heating the heat loss source 7 with the heating element 8. For conversion to standard voltages of 220 V or 380 V, the control cabinet contains a converting (step-up) transformer.

Example 2. Application of the method for power supply and control of the gate valve drive.

On the heated pipeline there is a gate valve with an electric drive (Fig. 6), which must be powered from an inductive-resistive electric heating system. The power consumption of the valve is, say, 400VA. The calculated heat losses from the prospective heated pipeline are assumed to be 50 VA / m (according to GOST 31610.30-2-2017 Appendix E, SP 41-103-2000 similar to example 1), taking into account 10% of the power reserve at a maintenance temperature of + 30 ° C and taking into account the coefficient power 0.92.

The current is determined in accordance with the textbook "Design and operation of electrical heating systems in the oil and gas industry" // ML. Strupinsky, N.N. Khrenkov, A.B. Kuvaldin. Chapter 6. Electrical heating systems based on induction-resistive heating (skin systems) and will amount to 107 A. Knowing the current, we determine the voltage drop (V / m):

Ssp. = Usp. I → Usp. = Ssp. / I = 50/107 = 0.467 V / m

Given the low power to power the valve, it is possible to use a 10% power reserve, that is, no more than 5 VA / m without damage to the heating of the main pipeline (50 VA / m * 10% = 5VA / m), in the section at least 400/5 = 80 meters (where 400 is the gate valve power, VA; 5 is the power per running meter, which can be used without damage to heating the main pipeline section (between two points of potential removal, VA / m. At 80 meters, with a voltage drop of 0.467 V / m , the potential difference will be 37.36 V (80m * 0.467V / m = 37.36V). This voltage must be brought to the standard 48V by increasing the distance between the junction boxes, (48V / 0.467V / m = 103m). 2 must be placed at a distance of 103 meters, while the potential difference on the conductor will be about 48 V, the maximum connected total power of the load should not exceed 400 VA (the maximum total power in this case, which can be removed from the heating section of the inductive-resistive system without damage (risk of freezing) between the points of potential removal (103 m).

Thus, at a distance of 103 meters from each other, junction boxes 2 with branching couplings 3 are installed, with the help of which branching is performed. All the necessary electrical equipment is located in the control cabinet 1 according to the schematic diagram in Fig. 3.

Example 3. Application of the proposed method for power supply of monitoring devices, control and management of a heated pipeline according to the second variant of the method (Fig. 7).

Take, for example, the length of the heated pipeline 2500 meters, we take the temperature of maintaining the heated pipeline not lower than +5 ° C, heat losses from the heated pipeline, at a given thickness and thermal conductivity coefficient of thermal insulation, are 40 VA / m (according to GOST 31610.30-2-2017 Appendix E , SP 41-103-2000 analogously to example 1). Knowing the running power (VA / m), the main electrical parameters of the system are calculated according to the book "Design and operation of electrical heating systems in the oil and gas industry", M.L. Strupinsky, N.N. Khrenkov, A.B. Kuvaldin. Chapter 6. Electrical heating systems based on induction-resistive heating (skin systems). In this case, to compensate for the calculated heat losses (40 W / m), the current will be 94.7 A. Knowing the current, we determine the voltage drop (Usp = Psp / I, Usp = 40 / 94.7 = 0.422V / m ).

To obtain a potential difference of 12 V (the minimum standard voltage for powering electronic equipment, in order to avoid non-standard equipment if possible), the distance on the conductor will correspond to 12 / 0.42 = 28.6 meters (L = U / Up).

Thus, at a distance of 29 meters from the control cabinet 1, located at the end of the electric heating line, a junction box 2 with a branching sleeve 3 (Fig. 7) is installed on the heating conductor 5 of the electric heating system, with the help of which the conductor 4 is branched to remove the potential. The removal of another potential occurs directly in the cabinet 1 at point N (Figs. 7 and 8).

Point "N" - the presence of zero potential at the end of the heating line:

- this is the place where the phase conductor is connected to a grounded heating pipe, which has zero potential, in the case of an inductive-resistive system;

- this is the junction of three phase conductors at one point (in a "star") in accordance with the first Kirchhoff's law, in the case of a resistive system.

Position 10 shows a wire that is used to remove the zero potential in cabinet 1.

11 - wires powered by potential removal.

Data from monitoring, control and management devices are entered directly into the modem 13, if there is a small number of signals, or through the data input module 14. Monitoring and control devices are installed on controlled objects (temperature, current, pressure sensors, etc.) outside the power and control device 1. Some control devices can be located inside the power and control device 1 (for example, instrument transformers). The power supply 12 is powered by the supply wires 11 (in special cases, a step-up transformer can be installed). The power supply, in turn, powers the modem 13 and the data input module 14. The data input module 14 receives information from external monitoring and control devices. This information is transmitted via modem 13 further, for example, using GSM technology or other. A rechargeable battery 15 can also be installed to ensure autonomous operation in the event of a system shutdown due to temperature conditions or alarms.

All the necessary electrical equipment is placed in cabinet 1 according to the schematic diagram (Fig. 10). Conversion of input signals can occur in special cases using a step-up transformer. Basically, the voltage for powering the devices is calculated. The power supply 12 acts as a stabilizer, but in some cases it can convert the voltage to a standard one, for example, to 220 V.

Thus, the invention provides power to the heating elements of sources of additional heat losses of industrial facilities, branch pipelines from the main heated facility, found on long pipelines heated by electrical heating systems, as well as to supply control and monitoring elements and other equipment for their own needs without building an accompanying network.

Claims (10)

1. A method of taking electricity from the linear part of the electric heating system of an industrial facility, which consists in the fact that two connecting elements are installed on the heating conductor of the electric heating system at a certain distance from each other, in each of which the heating conductor is spliced through a branching connector, and to the branched end of the connector connect an insulated electrical wire of the corresponding voltage class, by means of which the electric potential is removed and introduced into the power supply and control device for the heating element of the heat loss source or the actuator drive through the input corresponding to the installation zone of the heat loss source or the actuator, and the heating element of the heat loss source or drive the actuator is also connected to a power supply and control device. 2. The method according to claim 1, characterized in that an inductive-resistive or inductive or resistive system is used as the electrical heating system. 3. A method according to claim 1, characterized in that a junction box is used as the connecting element. 4. A method according to claim 1, characterized in that a branching sleeve is used as a branching connector, which consists of a branching sleeve and an insulating material with an appropriate class of insulation and ensuring tightness. 5. The method according to claim 1, characterized in that a box or a control cabinet containing a step-up transformer, a power supply, a residual current device, start-up circuit breakers, and overvoltage limiters is used as a power and control device. 6. A method of taking electricity from the linear part of the electric heating system of an industrial facility, which consists in the fact that at the end of the heating line, a power supply and control device for communication modules with monitoring and / or control devices and / or control of a heated industrial facility is installed, at a certain distance from which a connecting element is installed on the heating conductor of the electric heating system, in which the heating conductor is spliced through a branching connector, and an insulated electrical wire of the corresponding voltage class is connected to the branched end of the connector, by means of which the electrical potential is removed and introduced into the power and control device through an input corresponding to the zone of its installation , while the other potential is removed directly in the power supply and control device at the junction point of the phase conductor with a grounded heating tube having a zero potential, in the case of an inductive-resistive system, or in the point of connection of three-phase conductors at one point in the case of a resistive system. 7. The method according to claim 6, characterized in that an inductive-resistive or inductive or resistive system is used as the electrical heating system. 8. A method according to claim 6, characterized in that a junction box is used as the connecting element. 9. The method according to claim 6, characterized in that a branching sleeve is used as a branching connector, which consists of a branching sleeve and an insulating material with an appropriate class of insulation and ensuring tightness. 10. The method according to claim 6, characterized in that a box or a control cabinet containing a voltage stabilizer, starting protection circuit breakers, a residual current device, surge suppressors, a monitoring and control module, a modem for receiving / transmitting data is used as a power and control device from devices for monitoring, control and management of a heated industrial facility.

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