RU2495709C1 - Automatic gas odoriser system - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to natural gas motorisation and can be used for storing gas odorants in underground stores. Proposed system comprises underground tank with odorant, proportioning device, level gage, filter, manifold pipes with shutoff valves and accessories and control unit. Level gage composed of communicating vessel connected with underground store to be filled with odorant to whatever level in said store via bellows, its ends being located in odorant. Bellows top part is located above soil surface, filter and rotary pump being built therein. Level gage incorporate odorant level transducer and pipe connected with service tank incorporated with proportioner and provided with level indicator and temperature gage. Besides, this system includes deodorant, air assy and metering pump. Service tank hydraulic chamber is connected with metering pump while its gas chamber is connected with that of underground store. Deodorant and air assy are connected with underground store gas chamber.

EFFECT: complete automation, comprehensive control over consumption and level, notable decrease in overall dimensions and weight.

2 cl, 1 dwg

Description

The invention relates to means for automatically maintaining a given concentration of odorant in natural gas and can be used to odorize it using underground odorant storage tanks.

Odorization of natural gas is an essential safety factor in its industrial and domestic use. The best odorization plants available, which were developed instead of manual droppers, include injection-type dispensers for introducing portions of odorant into the natural gas stream in proportion to the gas flow rate according to established norms under excess pressure. The odorant is delivered to dispensers from consumable containers, which are periodically replenished by an odorant from underground storage tanks (or replaced by newly filled ones).

A modern block odorization device for gas distribution stations (GDS) of medium and higher gas productivity has very significant dimensions, weight and cost, the latter today, in some cases, exceeds 2 million rubles. This fact is one of the main reasons for the slow replacement of manual droppers with modern odorization devices.

The modern block odorization device is not fully automatic, because without the participation of the GDS operator, the problem of filling consumable containers from an underground storage tank has not been solved to date.

A device for regulating the flow of odorant (p. RF No. 2153189, IPC G05D 7/00, published 2000.07.20), related to the automatic control of fluid flow and used in the odorization process, which requires proportional dilution of gas with an odorant. The device contains a consumable container with an odorant, a sensing element, a metering pump. The metering pump is designed as a piston pneumatic hydraulic booster and provides a discrete metered odorant supply via a feedback signal with an odorized gas flow meter, the discharge line is connected through a cavitation venturi, in front of which a pressure sensor is installed, to flow tanks installed in series, connected to the gas pipeline through the main and reserve droppers, respectively, while the internal volume of the metering pump above the odorant supply piston, limited by a seal along the piston rod nya, communicated with the suction line through the check valve. However, the known device does not provide sufficient accuracy for regulating and supplying the odorant to the gas pipeline and does not provide reliable protection against leakage of the odorant into the atmosphere, in addition, the device is not provided with a device for monitoring the level of the odorant in the supply tank and has a large number of moving parts, which reduces their reliability and can lead to leaks of odorant and gas contamination of technical rooms.

The closest in technical essence to the claimed device is an automated gas odorization system ASOG ICFR. 423314.001 (see http: www.vvgnn.com). ASOG in versions with a working odorant storage unit is a metal cabinet in which are located: a dispensing device with a main unit - a plunger pump with an electromagnetic drive, two consumable containers and one buffer, a visual level indicator to control the filling of consumable containers, a filter, two droppers, ejector, pressure gauge, pressure gauge, piping piping with shut-off and control valves. Shelter adjacent to the cabinet for a container with a neutral gas - nitrogen.

Filling of consumable containers from an underground tank through a filter is carried out by squeezing the odorant with excess nitrogen pressure and pumping the odorant vapor with an ejector, filling control is carried out with a visual level indicator.

From consumable containers, the odorant flows by gravity into the dispensing device and then through the dropper into the gas pipeline. A buffer tank is necessary for the operation of the metering device during filling of consumable containers. During odorization, the gas pressure in all pipelines and tanks is the same and equal to the pressure in the gas pipeline. There is the possibility of odorization by the drip method in manual mode through another dropper. The electronic control unit located in the room for the GDS operator is connected to a gas flow computer and, with a frequency proportional to the gas flow, supplies electric pulses to the plunger pump electromagnet, after which a fixed dose of odorant is introduced into the gas pipeline.

The above device is selected as a prototype.

The disadvantages of the above devices are:

- the absence of an automatic mode of operation during filling of consumable containers from an underground tank, since the opening and closing of shut-off and control valves, the start-shutdown of an ejector, the filling level of consumable containers according to the visual level indicator is carried out by the GDS operator;

- the lack of automatic accounting of the amount of odorant consumed and the possibility of automatic correction of odorization according to the actual consumption of the odorant;

- lack of control of the odorant level in the underground tank;

- the lack of automatic correction of odorization in the case of partial odorization of gas outside the gas distribution system;

- large dimensions and mass of the cabinet with the system equipment, causing difficulties in its transportation and installation.

The technical task to be solved is the creation of an automatic gas odorization system for SAOPD, devoid of the disadvantages of the prototype.

The technical result consists in the complete automation of the work, the possibility of accounting for the amount of odorant consumed and the odorization correction based on the actual odorant consumption, the ability to control the odorant level in an underground tank, the odorization correction in the case of partial odorization of gas outside the gas distribution system, and a significant (multiple) reduction in the size and weight of the system.

To achieve a technical result in an automatic gas odorization system consisting of an underground tank with an odorant, a metering device, a level indicator, a filter, piping piping with shut-off and control valves, a control unit, a level indicator is installed as a communicating vessel with an underground capacity with the possibility of filling with an odorant up to at any level of the odorant in the underground tank, they are connected by a siphon, the ends of which are in the odorant, the upper part of the siphon is above the ground surface and embedded in it a liter and a centrifugal pump, in the level gauge there is an electric odorant level transducer and a pipeline connected to a flow metering tank from the metering device, equipped with a level switch and a temperature sensor, a deodorizer, a pneumatic unit and a metering pump are introduced into the system, while the hydraulic cavity of the tank is expendable -measuring is connected with the metering pump, and its gas cavity is connected with the gas cavity of the underground tank, the deodorizer and pneumatic unit are also connected with the gas cavity of the underground Noah capacity. Instead of a deodorizer, an ejector can be used.

A distinctive feature of SAOPD is that:

- instead of consumable and buffer capacities, a dispensing capacity is installed in the dispensing device, which differs by a factor of ten by a smaller volume and is equipped with a level switch and a temperature sensor;

- instead of the manual technology of filling consumable containers by squeezing the odorant with nitrogen from the underground tank, the direct pumping of the odorant from the underground tank to the metering centrifugal pump device was applied, the pump is built into the siphon above the ground surface, connecting the underground tank with a level indicator, while the centrifugal pump to the odorant of the underground tank is mounted;

- instead of a visual level indicator to control filling of consumable containers with an odorant, a level indicator is installed as a communicating vessel with an underground capacity with the ability to fill an odorant to any level of an odorant in an underground tank, with an electric level converter, which generally allows you to remotely control the odorant level in an underground tank regardless its designs and forms.

The listed differences, as well as a control unit with advanced functionality introduced into the deodorizer and pneumatic unit, allow you to create a fully automated gas odorization system with the ability to account for the amount of odorant consumed and odorization correction based on the actual odorant consumption, with the ability to control the odorant level in an underground tank, automatic correction of odorization in the case of partial odorization of gas outside the gas distribution system, with significantly smaller (several times) dimensions and material consumption system equipment. It should be noted that during the operation of the proposed system, shut-off and control valves are not used, and the internal volumes of the device to the metering pump from the inlet side are under a slight overpressure, which is an order of magnitude less than in the prototype. This increases reliability and safety.

The drawing shows a diagram of an automatic gas odorization system SAOPD, where 1 is an underground tank with an odorant, 2 is a metering device, 3 is a level indicator, 4 is a filter, 5 is a control unit, 6 is a centrifugal pump, 7 is an electric odorant level converter, 8 - flow-measuring capacity, 9 - level indicator, 10 - temperature sensor, 11 - deodorizer, 12 - pneumatic unit, 13 - metering pump, 14 - siphon, 15 - nitrogen tank.

SAOPD consists of an underground tank with an odorant 1, a level indicator 3 with an odorant, a siphon 14, the ends of which are always recessed into the odorant. A filter 4 and a centrifugal pump 6 are integrated in the ground part of the siphon 14. The level indicator 3 is equipped with an electric transducer of the odorant level 7 and is connected by a pipeline to a flow-measuring tank 8, the air cavity of which is connected by a pipeline to the air cavity of the underground tank 1. The pipelines are also connected to the latter, connecting the air cavity with a deodorizer 11 and a pneumatic unit 12, equipped with a cylinder of nitrogen 15. The capacity of the flow measuring 8 is equipped with a temperature sensor 10 and a level switch 9, together with a pump ohm metering 13 forms a metering device 2, connected to the gas pipeline. Monitoring and uninterrupted operation of ASOG is carried out using the control unit 5. The pipelines are equipped with shutoff valves (not shown in the drawing).

The device operates as follows.

Initially, all internal volumes of the device up to the metering pump 13 from the inlet side are at atmospheric pressure. Using a pneumatic unit 12 and a cylinder of nitrogen 15 in an underground tank with an odorant 1, a small maintained excess nitrogen pressure is constantly created with blocked pipelines to the deodorizer 11 and the gas cavity of the flow metering vessel 8. Under the influence of excess pressure, the odorant rises up the siphon 14 and fills the siphon 14 with a filter 4 and a centrifugal pump 6 and further in the level indicator 3 built into it. A prerequisite is to find the ends of the siphon in the odorant 14. After that, the gas pipeline opens Expendable cavity capacitance measuring 8, alignment odorant levels occurs in the underground tank 1 and the odorant level index 3. With electrical drive control unit 7 and the odorant level 5 is performed odorant level control in the underground tank 1.

When the drive of the centrifugal pump 6 is turned on, the odorant is pumped from the underground tank 1 to the level indicator 3 until it is completely filled and then through the pipeline to the expendable-measuring tank 8 to the upper level, after which the drive of the centrifugal pump 6 is automatically turned off and the alignment takes place odorant levels in the underground tank 1 and level indicator 3.

The receipt of the odorant from the flow metering tank 8 to the metering pump 13 of the metering device 2 occurs by gravity. When reducing the level of odorant in the capacity of the flow-measuring 8 to the lower level, the cycle of its filling is repeated again.

During a decrease in the odorant level in the flow-measuring tank 8, which is also a small volume measuring vessel, the time interval between two constant reference marks of the odorant level, which corresponds to the control volume of the odorant, is recorded. This volume is compared with the volume of the odorant, equal to the total number of unit doses when the metering pump is activated (volume unit dose is considered constant) for the same period of time. If the volumes do not coincide with the software of the control unit 5, the response frequency of the metering pump is corrected. A temperature sensor 10 is necessary to take into account changes in the density of the odorant and the volume of the flow-measuring container versus temperature, since the odorization rate is set in grams per unit volume of gas. Correction is done automatically.

When filling the underground tank with an odorant, the overpressure is released through the deodorizer 11, in which the odorant vapor is neutralized. During filling the underground tank, the odorization process does not stop. It is possible to use an ejector instead of a deodorizer.

The control unit and its software make it possible to receive standard unified current signals from stationary gas analyzers for mercaptans (the basis of the odorant) and automatically correct gas odorization in case of detection of an odorant in the gas supplied to the gas distribution station.

Claims (2)

1. Automatic gas odorization system, consisting of an underground tank with an odorant, a metering device, a level indicator, a filter, piping piping with shut-off and control valves, a control unit, characterized in that the level indicator is installed as a communicating vessel with an underground capacity with the possibility of filling with an odorant to any level of odorant in an underground tank, they are connected by a siphon, the ends of which are in an odorant, the upper part of the siphon is above the ground surface and a filter and centrifugal filter are built into it th pump, in the level gauge there is an electric odorant level transducer and a pipeline connected to the dispensing capacity of the dispensing device, equipped with a level indicator and a temperature sensor, a deodorizer, a pneumatic unit and a dispensing pump are introduced into the system, while the hydraulic cavity of the dispensing container connected to the metering pump, and its gas cavity to the gas cavity of the underground tank, the deodorizer and pneumatic unit are also connected to the gas cavity of the underground tank. 2. The system according to claim 1, characterized in that an ejector is used as a deodorizer.