Isothermal Modules for Liquid Carbon Dioxide (MIZU)

MIZhU was widely used in gas fire extinguishing installations for protecting facilities with a volume of over 1000 m3, for which the use of high-pressure gas fire extinguishing modules of the MGP type is becoming too costly.

Today we offer isothermal modules with a capacity of 3, 5, 10, 16, 25 m3 with a working pressure of 2.0 MPa, as well as modules with a capacity of 28 m3 with a working pressure of 3.0 MPa. The increased pressure allows the suppression of carbon dioxide to extinguish over longer distances. The modules are charged with liquid low-temperature carbon dioxide of the highest or first grade in accordance with GOST 8050.

A reversing-type locking-starting device (ZPU) is installed on the tank, designed to release CO2 in automatic or manual mode. The response time of the locking-starting device does not exceed 3 s. A short opening time of the locking and starting device allows to minimize the inertia of the gas fire extinguishing installation as a whole and, as a result, increase the efficiency of fire elimination. The main element of MIZU is an isothermal tank, which stores carbon dioxide in a liquid state. Isothermal fire tanks are equipped with the necessary shut-off and safety valves, alarm and control devices. Maintaining the working pressure in the tank is carried out using two refrigeration units, the evaporators of which are located in the upper part of the tank (in the gas cavity), and two electric heaters located in the lower part of its volume. This arrangement provides the efficiency of maintaining the working pressure at low ambient temperatures, as well as the quick recovery of the installation after refueling with CO2. The mass control of CO2 during storage is carried out using a weighing device consisting of four strain gauge sensors installed symmetrically under the tank supports. The control of the amount of carbon dioxide released from MIZHU is carried out by the loss of mass of the module. This control method allows with great accuracy (in contrast to the time release) to control the flow of carbon dioxide from the MIZHU tank.

To control the parameters MIZHU designed control cabinet. The control cabinet is based on programmable logic controllers. It features advanced functionality and an increased number of controlled parameters, has a 10.2 ”touch screen for easy input and output of information. The use of a voltage stabilizer in the cabinet increases the reliability of the refrigeration equipment during power surges at the facilities. The control cabinet has two RS-485 outputs for transmitting information via the open MODBUS protocol, for integration into control and dispatching systems (SCADA) at the facility. To create an automated workplace at the facility, a monitoring program is provided that provides operational control and visualization of the main parameters and equipment status, display of all events and malfunctions.

The control cabinet provides:

• display on the control panel and displays all the necessary information about the status of the equipment MIZHU, light and sound alarm when the parameters deviate from the norm;
• input up to 10 different values of the quantity of ZhU produced and automatic release of the corresponding mass according to the signal from the fire extinguishing system;
• control of the locking and starting device and monitoring of its condition;
• monitoring and maintaining the pressure in the tank within the specified limits - manual and automatic control of refrigeration units and electric heaters, self-diagnosis and restart after an accident;
• automatic switching of power circuits from the main power supply input 220 V, 50 Hz, to the backup from 24 V batteries in the absence of the main power supply, and vice versa when it is restored;
• SHU operation (and ZPU control) in standby mode and operation mode in the absence of main power supply by power supply from storage batteries for at least 24 hours;
• automatic recharging of batteries and their protection against deep discharge;
• control of the operation of safety devices;
• weight control ZhU and analysis of the readings of each weight sensor;
• automatic control of connecting lines for open circuit and short circuit;
• display and transmission of information about the state of actuators, sensors and technological parameters.

MIZHU can be operated at ambient temperatures up to minus 50 ° С, which allows installing the isothermal tank with the water heater in unheated rooms (a sufficiently light shelter to protect from rain and direct sunlight), thereby significantly reducing the capital cost of the fire protection facility. By special order it is possible to produce MIZHU with operating temperature up to minus 60 ° С.

In April 2015, the MIZhU successfully passed tests for compliance with the requirements of the 1st seismic resistance category according to NP-031-01, safety class 3H according to NP-001-15 with seismic effects of 9 points on the MSK-64 scale with the installation level above the zero mark up to 70 m inclusive, which allows the use of AUGP with MIZHU to protect objects in earthquake-prone zones.

Isothermal modules for liquid carbon dioxide of the MIZhU type are widely used in oil, gas and gas production, transportation and processing facilities (Gazprom, Transneft, Rosneft, NOVATEK, Asian Gas Pipeline, etc.), in the banking sector (“Bank of Russia”, “Sberbank of Russia”), at Rosatom enterprises and in other industries in Russia and abroad. The produced modules of the MIZhU type comply with the requirements of the Technical Regulation on fire safety requirements. The design of MIZHU is protected by eight patents. Isothermal modules for liquid carbon dioxide, such as MIZhU, were awarded the platinum mark “All-Russian Brand (III millennium). Quality mark of the 21st century ”, medals and diplomas of international and regional exhibitions.

With the help of MIZhU, fires were eliminated at several large enterprises, for example, almost immediately after the installation of an isothermal module to protect 4 oil refining furnaces in the city of Jalil (Tatarstan), in one of them, fire was prevented. At the end of 2006, the fire at the Gazturboservis facility (Tyumen) was eliminated.

The ARTSOK development and testing, conducted jointly with the oil industry enterprises and specialized research institutes, aimed at finding and implementing the latest fire protection methods and technologies at especially dangerous facilities, have no foreign and domestic analogues. Based on the results of long research work, from 2007 to 2014, the possibility of using automatic gas fire extinguishing systems based on the MIZhU to protect oil and oil products storage facilities was substantiated. Unique full-scale, including fire, tests were carried out under various climatic conditions on vertical steel tanks of the RVS-2000, RVS-5000 and RVS-20000 types, using domestic equipment. The research results formed the basis of the normative and technical document SP 155.13130.2014 “Warehouses for oil and oil products. Fire Safety Requirements ”, which establishes fire safety requirements for oil and oil products warehouses.