Engineering of technical complexes

Analytical review of the existing system

The existing system acted on the following cyclogram:

technical water at the B3 inlet, passing through the pressure increasing pump station, was supplied to the input of process equipment heat exchangers through the pipelines of the B3 system (supply system);

When passing through equipment heat exchangers, heated water under residual pressure was discharged into the pipelines of the B5 system (reverse system). Depending on the type of equipment, the discharge was carried out either directly to the B5 pressure return pipeline (for equipment without fracturing the jet), or to the non-stop return pipeline B5c (for equipment with fracturing the jet) under atmospheric pressure. Non-stop pipeline is located below zero elevation and has slope i = 0.02, towards drain;

from the B5 system, heated service water was discharged into a 15m3 tank located in the basement in the axes of the C5/U8 columns at an elevation of 4.75m below zero;

when filling the tank, the servo system of electrical automation gave a command to start the pumping station located directly in the basement. The pumping station pumped heated service water from the tank through the B4 system pipeline through the unit for discharge of standard clean effluents located in the axes of columns AD1/AE2.

Advantages of the current system:

technical simplicity;

low power consumption by pump stations operating in a re-short-term mode.

Deficiencies of the current system:

unreasonably high consumption of service water and drainage of regulatory clean effluents;

use in a service water system directly from an injection containing a large amount of active oxygen.

* The solubility of oxygen in water is inversely temperature dependent. For this reason, after passing through the equipment heat exchangers, there was an excess of active oxygen unbound with water in the cooling medium. Unbound oxygen aggressively affected pipelines and fittings, leading to premature wear and tear of the systems. The service life of the B5 system pipeline before complete wear was less than 4 years.

strong dependence of system operability on pressure at service water inlet B3;

low security of the system in case of failure of the devices. Severe consequences associated with the failure of electrical automation (complete flooding of pump stations, electrical equipment of pipe welding plants TVC4 and TVC5). The failure of the system led to the shutdown of most of the process chains in production for more than 24 hours with the condition of continuous emergency and recovery operations;

the system could not take into account the high degree of inertia of thermal systems and various heat flows on process equipment, depending only on the current mode of operation.

Analytical overview of the implemented system

The implemented system operates according to the following cyclogram.

Operating mode:

B3 direct input to process equipment is closed. The booster pump station is switched off;

inlet of V6 replenishment pipeline from B3 system is open. The replenishment valve is in automatic mode;

pump station M1 and M2 is switched on and in automatic mode. The supply piping system is filled with a pump station from a 15m3 tank and is under pressure;

After passing through equipment heat exchangers, heated water under residual pressure is discharged into B5 system pipelines (reverse system). Depending on the type of equipment, the discharge is carried out either directly to the B5 pressure return pipeline (for fracturing equipment), or to the B5c non-stop return pipeline (for equipment with fracturing) under atmospheric pressure. Non-stop pipeline is located below zero elevation and has slope i = 0.02, towards drain;

from system B5, heated service water is discharged back to the tank located in the basement room in the axes of the C5/U8 columns at 4.75m below zero;

the electroautomatics unit continuously monitors the temperature in the system. If the specified level is exceeded (adjusted), opens the replenishment valve Y1 in system B6. Cooling water is diluted with cold water from B3 system. When the cooling medium temperature is restored, the replenishment valve is automatically closed;

when the tank is replenished, the level in the system increases. The electroautomatics unit continuously monitors the level in the tank using operating mode level sensors. If the specified level is exceeded (adjusted), it opens the throttling valve of Y2 discharge of normal clean drains. The discharge occurs only within the limits of operating level maintenance in the tank. When the set lower level is reached, the reset is automatically disabled. Structurally, there is a higher flow through the discharge valve compared to the flow through the replenishment valve. The flow rate of the discharge valve is adjusted so that the pressure reduction in the supply system is within the limits of 10... 15% from the current one and does not affect the efficiency of the heat removal on the equipment.

The emergency mode (in case of failure of the devices) will be considered in the section of the technical design of the facility.

Disadvantages of the implemented system:

technical complexity, the need for special training of service personnel;

increased power consumption by pump stations operating in long-term mode.

Advantages of the implemented system:

significant reduction of service water consumption and water disposal of standard clean effluents;

use of water in the system that has undergone preliminary heating to a temperature close to the working one in an open tank (a significant part of oxygen has been removed);

small dependence of system operability on pressure at service water inlet V3. Possibility of starting and operation within 1.. 2 hours in autonomous mode (without replenishment);

special structural measures laid down during the design, aimed at protecting the system in case of failure of any of the main units (to be discussed in detail in the section of the technical design of the facility);

system takes into account a high degree of inertia of thermal systems and various heat flows on process equipment, depending only on the current mode of operation, making a decision on consumption of an additional amount of energy carriers in automatic mode based on the actual state.

Updated Terms of Reference

Design an automated service water supply complex for cooling the process equipment of the PAK GAZ pipe shop with the following characteristics:

pressure at inputs of equipment cooling systems 2.5... 3.5 kgf/cm2 (0.25... 0.35 mPa);

ensure operability and efficiency of the system at pressure at the service water injection unit within the limits of 0.8... 2.5 kgf/cm2 (0.08... 0.25 mPa);

provide the possibility of starting the system and operation in emergency mode at zero pressure at the service water injection unit;

ensure the possibility of maintenance and repair of the complex units without stopping it, since the system is trunk;

structurally ensure restoration of the system operation in case of failure of trunk devices and units in automatic mode with notification of operation and repair personnel about operation of the system in emergency mode. The allowable recovery time is not more than 10s (established in practice).