DE2749903A1 - DEVICE FOR EVAPORATION OF LIQUID NATURAL GAS WITH IMPROVED ENERGY BALANCE - Google Patents

Description

Registrants » Gutehoffnungshütte Sterkrade 2 7 A 9 9 0 3

Aktiengesellschaft, 4200 Oberhausen-Sterkrade

Device for the evaporation of liquefied natural gas with an improved energy balance

The invention relates to a device for the evaporation of liquefied natural gas (Liquefied Natural Gas = UiT,), with an evaporator connected to the LNG stream, which is connected in the circuit of a gas turbine system intended for electricity generation in a closed process, the circuit being heat energy is supplied via a heater.

In the liquefaction and re-evaporation of the from overseas countries LNG transported to the Federal Republic of Germany beats the energy consumption of the plants for liquefaction and for evaporation strong to book. In order to save energy, therefore, evaporation has been used The principle of combining power generation and LNG evaporation has been known for some time.

It has been shown that with a combination of LNG evaporation and power generation with gas turbines in a closed process, an extensive optimization of the recovery the energy is possible. A characteristic one

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The characteristic is the low compressor inlet temperature of -14O ° C. Because the efficiency of the process on the ratio the upper process temperature is dependent on the lower process temperature, very favorable efficiencies result. The overall degree of utilization of the system, i.e. the ratio of output power = electrical power + Heat output for LNG evaporation divided by the supplied fuel output can even reach over 80% can be increased. From this it can be seen that the use of a process scheme results in a fuel economy which, apart from low friction and radiation losses, largely converts primary energy into Usable energy enables.

Nitrogen is generally used as the working medium for the closed circuit, with 0.5% Oxygen is added to prevent nitrogen from entering the high temperature surfaces of the circulatory components to prevent. For the implementation of such devices it is advantageous that all components can be taken over by corresponding, already built gastubine systems. For the use known gas turbines only the compressor has to be adapted to the low inlet temperature.

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Despite the extraordinarily high degree of efficiency

reduce investment costs,

continue the task of improving the Xaie energy balance, Reduce losses and make it easier for the device to deliver its power to various requirements to make customizable.

This object is achieved with a device of the type mentioned at the outset, in which the heater is a heat exchanger which is connected to the exhaust gas flow of an internal combustion engine with a coupled generator.

The use of an internal combustion engine

preferably a diesel engine, brings significant advantages in terms of the task at hand. When used to generate electricity Serving internal combustion engine accumulate larger amounts of waste heat, in particular in the Combustion gases are included. It should be noted that under "internal combustion engine" there are also groups such machines are to be understood.

A generator is coupled to the output shaft of the internal combustion engine and its power output is relative can be set and changed easily with the help of the control of the prime mover. By taking advantage of the The exhaust of the internal combustion engine is the operation

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another generator in the closed system is possible. The overall degree of utilization of the system in the already defined sense can be increased up to 90% and more. The facility is to be set up economically and operate. The turbine can be taken over without modification. It does not require blade cooling. Recuperators and heat exchangers are also known. There is enough space for the LNG vaporizer Experience from low-temperature technology is available.

If the internal combustion engine, which is preferably a diesel engine, is operated with an exhaust gas turbocharger, then is possible,

a) the heat exchanger into the gas flow emerging from the turbine of the exhaust gas turbocharger or

b) the heat exchanger into the exhaust gas flow entering the turbine of the exhaust gas turbocharger

to switch. Depending on the prevailing operating conditions (temperature, pressure of the exhaust gases upstream and downstream of the exhaust gas turbocharger) optimal operating conditions can be determined. Another improvement in the energy balance in the sense of the task arises when the compression in the gas turbine plant Compressor and / or the expansion in the turbine with several heat transfer steps (waste heat release or /.

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recording) takes place.

Further amounts of heat can be transferred to the LNG, if Heat exchangers are flowed through by the combustion air or if a lubricating oil and / or cooling water cooler of the LNG are flowed through. These amounts of heat can also be transferred to the closed gas turbine circuit.

Although the device for the evaporation of LNG is known, which utilizes the waste heat of a diesel engine with a so-called Cold turbine works. The LNG is pumped through a heat exchanger, in which it evaporates completely will. A hydrocarbon-containing gas is fed to the heat exchanger in countercurrent, which gas in the heat exchanger condensed. The condensate is pumped through several other heat exchangers, which are connected to other heat exchangers are in connection that take the waste heat from the internal combustion engine at various points. In the diesel engine, a heat exchanger is switched into the exhaust gas flow and / or the combustion air flow

However, the use of a diesel engine in the manner already known does not suggest any technique is to be taken in a closed gas turbine circuit. In addition, mastery of technology can a refrigeration turbine lead to difficulties. The turbine

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poses numerous insulation and clogging problems, particularly from condensation products. Against it becomes more advanced in the present invention We have chosen a principle that guarantees largely trouble-free operation.

Examples for the realization of the invention are shown in Figures 1 and _f 2. 3 Show it:

Fig. 1 shows a device for LNG evaporation according to the invention, in which a heat exchanger the exhaust gas energy transmits the diesel engine to a closed gas turbine circuit;

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FIG. 2 shows a device according to FIG. 1, in which additional heat exchangers transfer the energy from combustion air, lubricating oil and cooling water to the LNG;

3 shows a device according to FIG. 2 with the energy transfer to the closed gas turbine circuit.

In Fig. 1 a first embodiment of the device according to the invention is shown. The device is characterized by three essential parts: the diesel engine 1 as a drive for a power-generating generator 2, the gas turbine 13 with the compressor 15 and the generator 16 and the evaporator for the LNG (liquefied natural gas).

The exhaust gas generated by the diesel engine 1 flows at a temperature T- = 42O ° C in a heat exchange with a temperature T ₂ = 125 ° C leaves.

temperature T ₁ «420 ° C. into a heat exchanger 9, which it

The working medium of a circulatory system operating in a closed process is fed to the heat exchanger 9 via a line 10. This has the temperature T_ = 100 ° C when entering the heat exchanger 9 and leaves it at about

T ^ ^β 40O ⁰ C. The working medium flowing out via line 11 - as already explained, it is nitrogen with a low percentage of oxygen - it enters the turbine 13, which via a shaft 14 with both a compressor and a Generator 16 is coupled .

The relaxed and with a temperature T. = 160 ° C from the

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Medium flowing in the turbine reaches the recuperator 18 via a line 17. After it has flowed through it, it reaches the LNG evaporator 3 at a temperature T = 30 ° C. Here, it is cooled down to a temperature T _fi = -140 ° C. At this temperature it reaches the compressor 15, in which it is compressed and brought to a temperature of T_ = -20.degree. After flowing through the recuperator 18, this temperature is _{increased to T Q} = 100 ^° C., via the line 10

Gas then back into the heat exchanger 9. The cycle begins again.

In Fig. 2 is an embodiment in a modified form shown. The exhaust gas generated by the diesel engine 1 first flows through a heat exchanger 9 and then through the turbine 5 of an exhaust gas turbocharger 6, which is also equipped with a compressor 7 for the incoming combustion air is. The combustion air flows from the compressor 7 into the diesel engine 1.

As far as the other elements of the device, in particular the closed turbine circuit, correspond, are the same Reference numbers have been chosen. A detailed description can be dispensed with.

In FIG. 2 it has also been indicated by dashed symbols that further heat exchangers are provided that are connected to the corresponding heat dissipation stations in the LNG pipeline. The following are provided: *

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Reference number 20 (heat exchanger in the circuit of the compressed combustion air) with a corresponding heat dissipation station 20 '; Reference number 21 (oil cooler) with corresponding station 21 ';

Reference number 22 (water cooler) with dispensing station 22 '.

In FIG. 3, the iCtane dispensing stations 20 ″, 21 ″ and 22 ″ are provided in the closed gas turbine circuit.

In the closed process with the gas turbine 13, the expansion of the turbine can advantageously take place in several intermediate steps with respective intermediate heating, as is known per se from the technology of the closed process. The same applies to the possibility of compressing the compressor with several intercoolings. These possibilities are not shown in the figures since they are known per se to the person skilled in the art.

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Claims (7)

Claims 1. Device for the evaporation of liquefied natural gas (LNG), with an evaporator connected to the LNG stream, which is in the circuit of an electricity generation certain gas turbine system is connected in the closed process, with the circuit thermal energy is fed via a heater, characterized in that the heater is a heat exchanger (9) which is inserted into the exhaust gas stream of a preferably internal combustion engine oT / with coupled generator (2) is switched. 2. Device according to claim 1, characterized in that the internal combustion engine is a diesel engine. 3. Device according to claim 1 or 2, with an exhaust gas turbocharger operated internal combustion engine, characterized in that the heat exchanger (9) in the gas flow emerging from the turbine of the exhaust gas turbocharger (6) is switched. 4. Device according to claim 1 or 2, with an exhaust gas turbocharger operated internal combustion engine, 909819/0406 characterized in that the heat exchanger (9) enters the turbine (5) of the exhaust gas turbocharger (6) Exhaust gas flow is switched. 5. Device according to claim 1, characterized in that the compression in the belonging to the gas turbine plant Compressor (15) and / or the expansion in the turbine (13) with several heat transfer steps he follows. 6. Device according to claim 1, characterized in that the waste heat energy from combustion air, lubricating oil and / or cooling water of the internal combustion engine (1) via the heat exchangers (20, 21, 22 or 20 ', 21', 22 ') is used for LNG evaporation. 7. Device according to claim 1, characterized in that the waste heat energy from combustion air, lubricating oil and / or Cooling water of the internal combustion engine (1) via the heat exchanger (20, 21, 22 or 20 ", 21", 22 ") is transmitted to the closed gas turbine circuit. 909819 / OAOS