EP2310747A2

EP2310747A2 - Method for continuously conditioning gas, preferably natural gas

Info

Publication number: EP2310747A2
Application number: EP09775870A
Authority: EP
Inventors: Andreas Lenk
Original assignee: Rohr- und Maschinenanlagentechnik GmbH; Energieversorgung Weser Ems AG
Current assignee: EWE Gasspeicher GmbH
Priority date: 2008-08-04
Filing date: 2009-05-12
Publication date: 2011-04-20
Anticipated expiration: 2029-05-12
Also published as: PT2310747E; RU2011103900A; EP2310747B1; US8899045B2; CA2734365A1; WO2010015214A3; HUE024525T2; DK2310747T3; WO2010015214A2; DE102008036243A1; PL2310747T3; US20110120011A1; RU2470225C2; ES2531829T3

Abstract

Before being fed into a pipe, particularly a network of pipes for the supply of consumers, gas, preferably natural gas, is continuously conditioned. The pressurized gas is removed from a reservoir, expanded, and heated to a predefined temperature before or after the expansion thereof in that a branched-off partial flow of the fed-out natural gas is mixed with oxygen and the resulting burnable gas is catalytically burned. The fed-out gas is heated with the thermal energy that is produced. For this purpose, a partial exhaust gas flow is branched off from a hot exhaust gas flow released during the catalytic combustion and conducted into a first container together with the cold burnable gas. The burnable gas is mixed with the supplied exhaust gas flow in the first container and is heated, and the mixture composed of the exhaust gas and burnable gas preheated in this way is conducted away from the first container into a second container, where it is subjected to the catalytic combustion, the heat of which is used to heat the fed-out gas to be conditioned to the respectively desired temperature.

Description

Process for the continuous conditioning of gas, preferably natural gas

The invention relates to a method for the continuous conditioning of gas, preferably natural gas, before it is fed into a pipeline, in particular a pipeline network for supplying consumers, in which the pressurized gas removed from a memory, relaxed and before or after its relaxation is heated to a predetermined temperature by a diverted partial flow of the gas stored is mixed with oxygen and the fuel gas thus formed is burned and in which the accumulated heat energy, the stored gas is heated.

Ergas must be heated during its withdrawal from underground storage to compensate for the Joule-Thomson effect before the pressure reduction. One possibility is a procedure of the aforementioned

Genus which is described in EP 0 920 578. The heat required for the heating is provided by catalytic "combustion" of a portion of the Ausspeicherstroms in a reactor In the known method by the catalytic reaction of oxygen with fuel gas, eg., Natural gas L, in the strong substoichiometric mixing area on the catalyst directly in the gas stream reaches temperatures of up to 400 ⁰ C. The heat utilization takes place by the mixing of the hot combustion gases as partial gas stream into the main gas stream behind the reactor The gas discharged from the storage tank has a pressure of 70 - 150 bar at a temperature of 5 - 30 ° C.

The catalytic "combustion" in the reactor requires an activation temperature of at least 180 ⁰ C - 250 ⁰ C. In order to reach the temperature, the diverted partial flow of the gas stored with

Oxygen is mixed and catalytically burned. The released

Heat can then be used to heat the stored gas to a temperature suitable for compensating for the Joule-Thomson effect associated with expansion and concomitant cooling.

In the known method, there is always a risk that the reactor in which the catalytic conversion of the fuel gas proceeds with the release of heat, is cold blown by the low temperatures of the stored natural gas, so that the oxygen remains in the fuel gas, without being reacted. This can be excluded in principle by the fact that the fuel gas-oxygen mixture is heated to the catalyst activation temperature of 180 - 250 ⁰ C prior to relaxation. Without this preheating the known process gets out of balance after a short time, because the activation temperature in the reactor is exceeded. On the other hand, the ignition in a process of metering oxygen into fuel gases, here natural gas, can never be completely excluded. This risk becomes even higher if, when the activation temperature of the reactor falls below the oxygen in the

Fuel gas remains because it was not converted. The oxygen concentration increases and thus the risk of auto-ignition at the high pressures occurring here. A safe execution of the known method is not guaranteed.

The invention has for its object to improve the known method so that a safe operation for conditioning is possible. This object is achieved by the features of claim 1. Further developments and advantageous embodiments will become apparent from the claims 2 to 9.

5

The constructive implementation of the process technology according to the invention, using the cooling of natural gas during expansion, in the design of the inlet of the expansion valves for cooling and mixing the gas streams before and after the second container (reactor), coupled with dew point LO measurements at the inlet and outlet of natural gas in which to carry out the

Provided plant, allow a targeted driving for the separation of water from the natural gas and thus the gas conditioning with respect to the Wasserdampftaupunkt or the drying of natural gas.

15 This method will continue to be coupled with special separator stages with multicyclones and filter elements as well as condensate discharges for optimum and safe driving and reduction and contamination of condensate (water) precipitated from natural gas with higher hydrocarbon chains.

.0

This represents a significant economic advantage over the known technique for gas conditioning or conditioning. The resulting condensates are easily separated by a downstream filter of hydrocarbons and are easy and inexpensive to dispose of> 5.

The user of the method according to the invention also benefits from the compact construction of a plant designed for its implementation in terms of space and plant costs, since all essential parts of a plant consisting of separator, preheating, gas pressure reduction and measurement, gas drying and filtration already in the Ver- integrated drive technology that can be structurally unite in a device.

The absence of moving parts, pumps and similar equipment reduces the operating and maintenance costs of carrying out the process. The combination of the catalytic conversion of oxygen and hydrocarbons to the catalyst of the reactor vessel, with the expansion directly into the mixing space and / or tangential to the cooling at the inlet around the second vessel, the reactor, causes the optimum precipitation of the condensates and condensation the water vapor from the catalytic reaction out, without local generation of exhaust gases, with a calculated efficiency of <1, 1, using the condensation and separation of the water vapor, and the heat of condensation.

The method advantageously takes advantage of the high inlet pressures of the natural gas and the usable cooling caused by the expansion to supply line pressure to separate the condensates from the natural gas. The method according to the invention is supported by the direct preheating in the first container and in the region of the supply lines into the second container, through which immediate dissolution or suppression of the gas hydrate formation can be utilized. If the use of the pressure gradient is not sufficient to achieve complete condensation, an absorption medium for binding the water vapor in the natural gas stream can be injected in support of the entry of the main gas stream into the second container.

The absorbent, z. As triethylene glycol is discharged together with the condensate from the conditioning process and can, like the condensate, collected and then processed, so it is reusable.

In terms of process technology, the control of the conditioning process takes place dew-point-controlled via the inlet and outlet of the natural gas in the am Entry and exit of the natural gas in a device provided for carrying out the method according to the invention installed dew point by selective variation of oxygen addition and variation of the flow control over the control valves of the main gas flow to the tangential inlet via the supply lines and the reactor or

Add directly into the mixing zone or the mixing space between the second container and a downstream separator. Thus, the method is particularly safe, especially since the addition of oxygen in the mixing container can still be assigned a safety device with nitrogen extinguishing.

An embodiment of the method according to the invention, from which further inventive features arise, is shown schematically in the drawing in the form of a flow chart.

The natural gas to be conditioned, before being fed into a pipeline 1 of a pipeline network, not shown, for the supply of consumers, taken from a memory also not shown and flows out of the memory via a main line 2 from. The flow direction is indicated here by arrows.

In the branch point 3 is from the main line 2 from a branch line 4, via which a partial flow of the natural gas stored in a mixing vessel 5 is passed.

Via the line 6 5 gaseous oxygen is passed into the mixing vessel, which mixes in the mixing vessel 5 with the supplied via the branch line 4 natural gas partial stream.

In the mixing vessel 5, a fuel gas is thus formed, which is passed via the fuel gas line 7 into the first container 8 with closed container walls 9. The first container forms the preheating station, which is designed as a jet pump, which has a driver nozzle 10 and a catching nozzle 11 having. About the driver nozzle 10, the supplied from the fuel gas line 7 at relatively high pressure fuel gas is injected into the first container 8, wherein the emerging from the driver nozzle 10 free-jet is collected by the catching nozzle 11 and mixed on his way with befindlichem in the container 8 exhaust gas and heated, which is supplied via the suction line 12 as a partial exhaust stream from a catalytic combustion process.

The heated fuel gas mixture flows via the mixing line 13 into a reactor chamber 14 of a second container 15, which is designed as a housing enclosing the reactor 14, a mixing chamber 17 and a separator 18.

The jet pump located in the first container 8 sucks hot natural gas out of the reactor 14 via the suction line 12 and mixes it with the cold fuel gas which flows in from the mixing container 5.

The entering from the main line 2 under Vorschaltung of expansion valves via the leads 21 and 22 in the housing of the second container 15 cold natural gas flows around the reactor vessel 14, wherein it around the reactor vessel 14 around with guide elements 23 which are arranged helically at the periphery thereof becomes.

The second vessel 14 contains a reactor bed in the form of a bed of catalytic granules vaporized with palladium and / or platinum.

Preheated fuel gas enters the second container 14 via the preheating line 13. The temperature is adjusted by suitable control technology so that an activation temperature of the reactor bed in the second container 14 of about 180 ° C to 250 ⁰ C is reached.

The fuel gas burns catalytically and the heat released in this process is partly transferred to the second container 14 via the outer circumferential surface. flowing, supplied via the leads 21 and 22 supplied cold natural gas.

Device measures are taken to ensure that the natural gas preheated via the outer jacket surface is mixed with the cold natural gas supplied via the supply line 22.

The catalytically burned fuel gases enter from the second container 14 directly into the mixing chamber 17, where they mix with the flowing through the supply line 22 cold natural gas.

By this cooling, on the one hand on the outer circumferential surface of the reactor 14, on the other hand by the passage of the hot fuel gases into the cold natural gas in the mixing chamber 17, immediately hydrate formation with appropriate condensate, which are discharged through the condensate drains 23 and 24.

The separator 18 is flowed through from the mixing chamber 17 derived, now heated natural gas, which precipitated in the separator 18 more condensate and the natural gas is also filtered.

The separator 18 also has a condensate drain 25.

Denoted by 26 is a device for assisting the separation of condensate, by means of which an absorbent, for. B. triethylene glycol for binding the water vapor in the gas stream of the supply lines 21 and 22 is injected.

27 denotes a safety device, by means of which the oxygen feed 6 is also controlled and regulated. Dew point sensors at the entrance and exit of the apparatus for carrying out the method are designated 28 and 29. The links with pressure sensors and temperature sensors are indicated here by dashed lines only.

Claims

claims

1 _{, a} method for the continuous conditioning of gas, preferably natural gas, before it is fed into a pipeline, in particular a pipeline network for supplying consumers, in which the pressurized gas taken from a memory, relaxed and before or after its relaxation to a predetermined temperature is heated by a diverted partial flow of the stored natural gas mixed with oxygen and the fuel gas thus formed is catalytically burned and is heated with the resulting heat energy, the stored gas, characterized in that of a liberated in the catalytic combustion hot exhaust gas flow Diverted exhaust gas stream, and is passed together with the cold fuel gas in a first container (8), that the fuel gas in the first container (8) is mixed with the supplied exhaust gas partial stream and thereby heated, and that the thus preheated mixture of exhaust gas and fuel gas the first container (8) is discharged into a second container (15), in which it is subjected to the catalytic combustion, with the heat of which the stored and to be conditioned gas is heated to the particular desired temperature.

2. The method according to claim 1, characterized in that the stored natural gas is expanded immediately before its introduction into the second container (15).

3. The method according to claim 2, characterized in that the expanded natural gas is divided into partial streams, of which at least one by one

Reactor (14) of the second container (15) and at least one further partial flow is introduced into a mixing chamber (17) of the second container (15), wherein in the mixing chamber (17) at the same time from the reactor (14) outgoing partial flow of heated natural gas is introduced.

4_. Process according to Claim 3, characterized in that the gas stream leaving the mixing chamber (17) is passed through a separator (18).

5. The method according to claim 4, characterized in that in the reactor (14) of the mixing chamber (17) and in the separator (18) resulting condensates are discharged into a condensate trap.

6 ^ A method according to claim 5, characterized in that an absorbent for binding the water vapor is injected into the gas stream to support the condensate separation.

7. The method according to claim 6, characterized in that triethylene glycol is used as the absorbent.

8_, Method according to one of the preceding claims, characterized in that the dew point of the natural gas stored at least before entering the first container (8) and after exiting from the second

Container (15) is measured that, in dependence on measured dew point values, an oxygen addition and a flow control of the guided into the second container (15) natural gas flow is varied.

9. The method according to claim 8, characterized in that the variations of oxygen addition and flow control are performed programmatically.