CN210237553U

CN210237553U - Facility system for effectively adjusting heat value of natural gas

Info

Publication number: CN210237553U
Application number: CN201920868447.9U
Authority: CN
Inventors: Jiang Wu; 武江
Original assignee: Wuhan Gas & Heat Planning And Design Institute Co ltd
Current assignee: Wuhan Gas & Heat Planning And Design Institute Co ltd
Priority date: 2019-06-11
Filing date: 2019-06-11
Publication date: 2020-04-03
Anticipated expiration: 2029-06-11

Abstract

The utility model relates to a facility system for effectively adjusting natural gas heat value, which comprises a natural gas main pipe, an air main pipe and a static mixer, wherein the natural gas main pipe is connected with the inlet of the static mixer through a first control valve, a first pressure gauge, a first cylinder type filter, a first pressure stabilizing valve, a first flow meter and a first check valve in sequence; the air main pipe is connected with an inlet of the static mixer sequentially through a second control valve, a second pressure gauge, a safety shut-off valve, a second barrel filter, a second pressure stabilizing valve, a second flow meter, a pneumatic membrane regulating valve, a third pressure gauge, a second check valve and a third control valve. And the outlet of the static mixer is connected with a downstream air supply port through an oxygen content analyzer, a heat value analyzer, a safety relief valve group, a fourth pressure gauge, a pressure transmitter and a fourth control valve in sequence. The utility model discloses application scope is wide, and the regulation performance is good, and safe and reliable can be effective, quick mix volume according to follow-up flow control air, guarantees that the calorific value of gas mixture satisfies gas demand for low reaches.

Description

Facility system for effectively adjusting heat value of natural gas

Technical Field

The utility model relates to an effectively adjust facility system of natural gas calorific value is particularly useful for the occasion that needs adjust in order to accord with low reaches gas demand to upper reaches natural gas calorific value.

Background

The natural gas produced by different gas sources has different heat values and components. With the continuous development of natural gas markets in China, gaps between supply and demand of natural gas become larger and larger. The introduction of natural gas from abroad has been imported shipping LNG (liquefied natural gas) in addition to long-distance pipelines. After the ship-borne LNG is separately transported by the LNG receiving station, the LNG is gasified and supplied in the LNG gasification station. The calorific value of foreign natural gas often exceeds national standards, and in order to stabilize the calorific value and reflect the economy of gas supply, a certain proportion of air (nitrogen) needs to be mixed in the natural gas at a proper time.

In addition, with the development of industry in China, more and more industrial equipment needs more accurate combustion control so as to meet the requirement of increasingly accurate and strict temperature control in industrial production. Slight fluctuations in the upstream natural gas heating value can be a serious detriment to some delicate equipment, and therefore high quality natural gas heating value adjustment systems are required to meet production requirements.

Disclosure of Invention

The utility model aims to solve the problem that a facility system of effective adjustment natural gas calorific value is provided, this system application scope is wide, and the regulation performance is good, and safe and reliable can satisfy the follow-up regulation of natural gas calorific value.

The technical solution of the utility model is that: a facility system for effectively adjusting the heat value of natural gas comprises a natural gas main pipe, an air main pipe and a static mixer, wherein the natural gas main pipe is connected with an inlet of the static mixer through a first control valve, a first pressure gauge, a first cylindrical filter, a first pressure stabilizing valve, a first flow meter and a first check valve in sequence; the air main pipe is connected with an inlet of the static mixer through a second control valve, a second pressure gauge, a safety shut-off valve, a second barrel type filter, a second pressure stabilizing valve, a second flow meter, a pneumatic membrane regulating valve, a third pressure gauge, a second check valve and a third control valve in sequence; the outlet of the static mixer is connected with a downstream air supply port through an oxygen content analyzer, a heat value analyzer, a safety relief valve group, a fourth pressure gauge, a pressure transmitter and a fourth control valve in sequence.

The utility model discloses still include the PLC controller, safety cut-off valve's cut-off signal input part connect respectively from oxygen content analysis appearance, calorific value analysis appearance and muddy gas back pressure transmitter's cut-off signal output part through the PLC controller.

The regulating signal input end of the pneumatic membrane regulating valve is respectively connected with the regulating signal output ends of the oxygen content analyzer and the heat value analyzer through the PLC, and is simultaneously respectively connected with the flow signal output ends of the first flowmeter and the second flowmeter through the PLC.

A flow disturbing net is arranged in the static mixer; the static mixer is divided into a front chamber and a rear chamber by the turbulence net, and a pressure difference meter connected with the front chamber and the rear chamber of the static mixer is arranged on the static mixer.

The utility model discloses application scope is wide, and the regulation performance is good, and safe and reliable can be effective, quick mix volume according to follow-up flow control air (nitrogen gas), guarantees that the calorific value of gas mixture satisfies the follow-up regulation and the low reaches gas demand of using of natural gas calorific value.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Fig. 2 is a schematic diagram of the self-control logic of the present invention.

Detailed Description

Referring to fig. 1, the utility model comprises a natural gas main pipe TG, an air main pipe KG and a static mixer 8, wherein the natural gas main pipe TG is connected with an inlet of the static mixer 8 through a first control valve 1a, a first pressure gauge 14a, a first cylindrical filter 4a, a first pressure stabilizing valve 5a, a first flow meter 6a and a first check valve 12a in sequence; the main pipe KG of air (nitrogen) enters and is connected with the inlet of the static mixer 8 after passing through a second control valve 1b, a second pressure gauge 14b, a safety shut-off valve 3, a second cylinder type filter 4b, a second pressure stabilizing valve 5b, a second flow meter 6b, a pneumatic membrane regulating valve 7, a third pressure gauge 14c, a second check valve 12b and a third control valve 1c in sequence. After the fuel gas and the air (nitrogen gas) in the static mixer 8 are fully mixed, the fuel gas and the air are sequentially connected through the oxygen content analyzer 9, the heat value analyzer 10, the safety relief valve group (1 i, 11, 1j, 2, 13), the fourth pressure gauge 14d, the pressure transmitter 15 and the fourth control valve 1d, and then the mixed gas enters a downstream air supply port.

The cut-off signal input end of the safety cut-off valve 3 is derived from a PLC, and the PLC is respectively connected with the cut-off signal output ends of the oxygen content analyzer 9, the heat value analyzer 10 and the mixed gas rear pressure transmitter 15 aiming at the source of the cut-off signal. And when the oxygen content of the mixed gas exceeds the limit, the heat value cannot meet the requirement and the pressure after the gas mixing exceeds the limit, the safety cut-off is implemented.

A flow disturbing net 8b is arranged in the static mixer 8 and divides the static mixer into a front chamber 8a and a rear chamber 8c, and a pressure difference meter 16 connected with the front chamber 8a and the rear chamber 8c of the static mixer is arranged on the static mixer.

The pneumatic membrane regulating valve 7 has a valve position feedback function, the regulating signal input end of the pneumatic membrane regulating valve comes from a PLC (programmable logic controller), and the PLC is respectively connected with the regulating signal output ends of the oxygen content analyzer 9 and the heat value analyzer 10, the flow signal output ends of the natural gas main pipeline flowmeter 6a and the air (nitrogen) main pipeline flowmeter 6b aiming at the source of the signal, so that the primary regulation and the precise regulation of mixed gas can be realized.

Except for special description, the instruments, meters and equipment related in the utility model are all known products.

See fig. 2. The control flow comprises the following steps:

① the mixing system adopts a gas mixing mode with follow-up flow, firstly, the raw gas enters into a pipeline, namely pure natural gas enters into the pipeline, and a heat value analyzer 10 at an outlet detects the heat value (of the raw gas) (the detection speed of the heat value analyzer is 5-10 s);

② heat value signal and flow signal of the natural gas main path flowmeter 6a are input and transmitted to the PLC, and the gas mixing proportion and the gas mixing flow are calculated according to the set target heat value;

③ the flow signal input of the air (nitrogen) main path flowmeter 6b is also transmitted to the PLC to calculate the adjusting signal, the adjusting signal is transmitted to the pneumatic film adjusting valve 7, the adjusting valve starts to act for coarse adjustment, the opening of the adjusting valve is gradually opened to gradually reach the set value of the heat value;

④ when the pneumatic membrane adjusting valve 7 is adjusted to the appointed opening, the heat value analyzer 10 detects the heat value signal after mixing the gas, the oxygen content analyzer 9 detects the oxygen content signal, if the deviation of the detected heat value, oxygen content and target heat value, oxygen content is in the setting range, the adjusting valve keeps the opening not to act, the adjustment is considered to be completed, if the deviation of the heat value detected by the heat value analyzer 10 and the target heat value exceeds the setting range, but the deviation of the oxygen content detected by the oxygen content analyzer 9 and the target oxygen content is in the setting range, the PLC recalculates a proportion, transmits the proportion to the flowmeter, the flowmeter gives a signal to the adjusting valve, and continues the opening adjustment until the deviation of the heat value detected by the heat value analyzer and the target heat value is in the setting value;

⑤ when the oxygen content analyzer 9 detects that the oxygen content of the mixed gas exceeds the limit value, the heat value analyzer 10 detects that the heat value of the mixed gas can not meet the requirement or the pressure transmitter 15 detects that the pressure of the mixed gas exceeds the limit, the safety cut-off is implemented.

Claims

1. A facility system for effectively adjusting the calorific value of natural gas is characterized in that: the natural gas main pipe is connected with an inlet of the static mixer through a first control valve, a first pressure gauge, a first cylindrical filter, a first pressure stabilizing valve, a first flowmeter and a first check valve in sequence; the air main pipe is connected with an inlet of the static mixer through a second control valve, a second pressure gauge, a safety shut-off valve, a second barrel type filter, a second pressure stabilizing valve, a second flow meter, a pneumatic membrane regulating valve, a third pressure gauge, a second check valve and a third control valve in sequence; the outlet of the static mixer is connected with a downstream air supply port through an oxygen content analyzer, a heat value analyzer, a safety relief valve, a fourth pressure gauge, a pressure transmitter and a fourth control valve in sequence.

2. A facility system for efficiently adjusting the heating value of natural gas according to claim 1, wherein: still include the PLC controller, the shut off signal input part of safety cut off valve connect respectively from oxygen content analysis appearance, calorific value analysis appearance and the shut off signal output part of mixing gas back pressure transmitter through the PLC controller.

3. A facility system for efficiently adjusting the heating value of natural gas according to claim 2, wherein: the regulating signal input end of the pneumatic membrane regulating valve is respectively connected with the regulating signal output ends of the oxygen content analyzer and the heat value analyzer through the PLC, and is simultaneously respectively connected with the flow signal output ends of the first flowmeter and the second flowmeter through the PLC.

4. A facility system for efficiently adjusting the heating value of natural gas according to claim 1, 2 or 3, wherein: a flow disturbing net is arranged in the static mixer; the static mixer is divided into a front chamber and a rear chamber by the turbulence net, and a pressure difference meter connected with the front chamber and the rear chamber of the static mixer is arranged on the static mixer.