JPS60216061A - Fuel gas feeder for gas internal-combustion engine - Google Patents

Abstract

PURPOSE:To feed fuel safely to an engine while self-conditioning the fuel gas temperature by providing a valve for passing the compressed fuel gas prior to starting in a bypass connecting between the vicinity of internal-combustion engine arranged in a compressed fuel gas feed path and the suction side of compressor. CONSTITUTION:The piping A in the downstream of a drain separator 24 is branched into the bypass system piping B returning to the mist separator 20 and the internal-combustion engine system piping C to be coupled through a heatexchanger 22 with the internal-combustion engine 26. The fuel gas returning from the piping B to the gas inlet 29 is heated excessively because of the friction heat of compressor, thereby it is passed through an after-cooler 28. Heat exchanger volume Q will decrease as the flow G of the fluid to be heated decreases to suppress the temperature rise of said fluid while since the delivery fuel gas of compressor is employed as the heating fluid of heatexchanger 22, self-conditioning function for preventing over heat is provided to the heatexchanger 22.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel gas supply device that supplies superheated fuel gas to a gas combustion internal combustion engine, that is, a gas turbine and a gas engine.

ff, the fuel gas in the upper dd gas combustion internal combustion engine is
rms is supplied to the internal combustion engine with increased pressure through compression;
The temperature of the gas compressed by the compressor is usually too high for internal combustion engines, so it is necessary to cool it in the aftercooler.

Also, when cooled by the aftercooler, some components of the fuel gas condense and liquefy due to the temperature drop, creating drain, but even if the drain is removed by the drain separator downstream of the aftercooler, some drain mist remains. . This drain mist can clog the fuel control system of the internal combustion engine and cause trouble, so in order to prevent this, the saturated or supersaturated fuel gas that has been cooled in the aftercooler is heated to turn it into superheated gas. Conventionally, this heating was performed by a heater l provided by an external Am as shown in Figure i/.In Figure 1, 2 is a mist separator, 8 is a compressor, 4 is an aftercooler, and 5
is a drain separator, 6 is a gas combustion type internal combustion tube, 7 is a negative nail connected to this internal combustion a6-, 8 is a pressure control device, 9
is a pressure regulating valve controlled by a pressure control device. The heater l in this example is a heat exchanger whose heat source is a heating fluid sent from the outside. And further temperature control device tlO
The control device 10 controls the flow rate regulating valve 11 while constantly detecting the temperature of the fuel gas sent to the internal combustion engine 6, thereby controlling the heating by the heater 1 and sending it to the internal combustion engine 6. This was done to prevent the fuel gas from heating too much or not enough.

The above-mentioned conventional fuel gas supply device, which uses an external heat source to make the gas superheated, has the following drawbacks. Namely.

(1) A special external heat source is required.

(2) In the case of the heater I using a heat exchanger, if a gap 43 occurs between the fuel gas in the heater I and the heating fluid, it will cause a big trouble.

(3) If the heater is a heating type, the surface temperature of the heater becomes high, so there is a problem that it does not comply with domestic regulations as an explosion-proof product.

This invention was proposed in order to eliminate the above-mentioned conventional drawbacks, and employs a heat exchanger that uses the fuel gas discharged from the compressor as a heating source, eliminating the need for an external heat source and achieving energy savings.
Another object of the present invention is to provide a fuel gas supply device that can self-adjust the fuel gas temperature and safely supply fuel to an internal combustion engine without particularly providing a temperature control device, and that has a simple configuration.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, 20 is a mist separator, 21 is a positive displacement type, turbo type, axial type, etc. compressor, 22 is a heat exchanger, 2
8 is an aftercooler (cooler), 24 is a drain separator, zl) is a filter, S6d is a gas combustion type internal combustion engine such as a gas turbine or gas engine, 27 is a load, and 28 is an auxiliary drain separator for use before starting the internal combustion engine. It is. Then, the fuel gas supplied from the gas inlet 29 as shown by the arrow (A) is compressed by the mist separator zO1 [211,
Heat exchanger 22, aftercooler 28, drain separator z
Furthermore, the piping A downstream of the drain separator z4 is connected to the piping B of the bypass system that returns to the mist separator 20, and to the internal combustion engine z6 via a heat exchanger ``l1i2!'' and a filter 25. The piping C of the internal combustion engine system (of which the piping Cs upstream of the heat exchanger z2 and the piping downstream is the C warehouse) is branched to the piping C of the internal combustion engine system. and the thrust separator 20 are provided with pressure control values rL, respectively, for detecting the gas pressure and outputting a control signal according to the pressure, and the pipe B is provided with a pressure I14 regulating valve 82. This pressure dl
The l valve 82 is normally controlled by the pressure control device 80 of the pipe A, but when the pressure inside the mist separator 20 (that is, the suction pressure of the compressor 21) drops abnormally,
The selection control device 88 selectively operates the pressure control device 81 in the mist separator 20 according to a control signal.

Next, the operation of the above-mentioned fuel gas supply device will be explained.

l) Fuel gas with a gas population of 2 g usually has a temperature of room temperature and a pressure of 10 to 1.0 kI/1iA (absolute pressure).

2) Approximately qθ% of the normal mist by the mist separator 20
is removed.

3) At the suction port of the compression a21, the pressure decreases to the gas population 2 due to pressure loss in the mist separator 20 and piping system.
The pressure at 9 is normally about 02 to tOk/- lower.

Hiroshi) On the discharge side of the compressor 21, the discharge pressure is usually lO~t.
t, h/dAc This is internal combustion! What is the discharge pressure equal to the required gas pressure of θ~/
The temperature is 30°C.

Note that the discharge temperature is determined by the following equation.

However, in the case of reversible adiabatic compression (positive displacement compression a), however, in the case of polytropic compression (turbo compressor), Td: discharge temperature (0K) TS: suction warm temperature (0K) Pd: discharge pressure (b /mA) P8: Suction pressure (ha / dA) K: Gas constant ratio Cp /CV Cp: Constant pressure specific heat Cv; Constant volume specific heat n: Exponent in case of polytropic change , the discharge pressure Pd of the compressor z1 is lowered to t'L#f, and the discharge temperature [Td
It also goes down.

The discharge pressure Pd of the compressor 21 is controlled by the pressure control device 80.
It can be lowered by lowering the set value of.

t) In the heat exchange 'a22', the high-temperature gas discharged from the compressor [21] gives thermal energy to the low-temperature gas flowing through the pipe c' of the internal combustion engine system to heat it. The phenomenon of heat exchange will be described in more detail later.

6) The high temperature gas that has been slightly cooled in the heat exchanger 22 is cooled again to near room temperature in the aftercooler 2z8.

At this time, the components contained in the fuel gas are condensed and liquefied as the temperature decreases. Note that depending on the type of cooler, this condensed liquid may be discharged through the drain outlet of the -0 cooler.

? ) The condensate entrained in the cooled fuel gas is separated and removed by the drain separator 24.

g) Fuel gas corresponding to the capacity of the compressor 21 flows between the gas population 29 and the pipe A downstream of the drain separator 24.

g) The amount of fuel gas required by the internal combustion engine 426 is branched and sent to the piping C of the internal combustion engine system.

The fuel gas, which was in a saturated or supersaturated state before entering the heat exchanger 2z, is heated by the heat exchanger 22 and turned into superheated gas, which is then supplied to the internal combustion engine 26.

The fuel gas sent to the pipe C of the WSa system is the negative ftr2 of the internal combustion engine 26 as described above. Since only the amount corresponding to the amount flows, the surplus fuel gas returns to the gas population 29 via the pressure regulating valve 8B and the pipe B.

Therefore, the pressure is detected by the pressure control device 80, and the pressure regulating valve 82 is opened according to the detected pressure.
- By adjusting, the pressure of the fuel gas sent to the pipe C of the internal combustion engine system can be kept constant.

Note that the fuel gas returning from the bypass system arrangement fB to the gas population 2g must pass through the aftercooler z8. This is because, even if the compressor 21 is a positive displacement type, compression is not achieved through a complete reversible adiabatic change.
In reality, it is heated excessively due to the frictional heat of the compressor, so even if the compressed still-temperature gas is adiabatically expanded by the pressure valve 14 and the valve 82, it will not return to the original supply gas temperature. Not going down,
Therefore, if this bypass gas were to be circulated, it would be synergistically heated by the compressor 21, and as a result, the temperature of the discharged gas at the pressure saw t would rise, causing mechanical problems. Melt.

//) Pressure control value of mist separator 20g@ft81
outputs a control signal in the same way as the pressure control device 80 of the pipe A downstream of the drain separator 24, and normally select control i! Ignored by I device 88. However, when the supply amount of fuel gas at the gas inlet 2g decreases and the suction pressure of compression*21 falls below a certain value, the selection control device 8B switches the pressure regulating valve 82 to the mist separator 20 side. It is controlled only by the pressure control value gjt,81. In this case, the pressure control device BO of the pipe A is ignored, and the pressure regulating valve 82 is controlled to open so as to return the gas from the discharge 14111 of the compressor g21 to the suction side and prevent a pressure drop on the suction side of the compressor 21. I'm sorry. This is pressure ma
If the suction pressure of the ui decreases, it will have a permanent effect on the compressor 21KN and cause it to malfunction.However, if the suction pressure gets close to vacuum, there is a possibility that air will be sucked in, which is extremely dangerous. This is because protection of the compressor 21 is given priority over supply to the internal combustion engine 26. When the amount of fuel supplied to this tank 29 decreases and the pressure in the piping C of the internal combustion engine system drops below a certain value, the fuel system must be switched to another fuel system (usually liquid fuel) not shown, or the internal combustion mirror 26 must be switched to another fuel system (usually liquid fuel). Stop driving.

+2) Also, the auxiliary drain separator z8 is used when starting the internal combustion engine 26. Before starting, close the valve 84 in front of the internal combustion engine 26, and close the valve 84 on the side of the auxiliary drain separator 28.
5 is opened to operate the compressor 4i 221, the fuel gas is circulated to warm the cold pipes, and after each pipe is warmed up, the internal combustion engine 26 is started. This makes it possible to supply preferable superheated gas to the internal combustion a26 from the beginning of startup.

Next, what about the heat exchanger 22 described in the (evening) section above? ! I will describe the phenomenon of single-father replacement.

Generally, the amount of heat exchanged Q in a heat exchanger is determined by the following formula.

Q-UXAX△im ・・・・・・・・・・・・・・・
(,11) U: overall heat transfer coefficient A: heat transfer area (constant) △trrz logarithm mean temperature difference △ts -'l' tube -1+ △tm-'fr is Maro/I'l, heat of two heating fluids Temperature at the inlet of the exchanger T: Temperature of the heated fluid at the outlet of the heat exchanger tI: Temperature of the heated fluid at the inlet of the heat exchanger Snow: Temperature of the heated fluid at the outlet of the heat exchanger , the flow *) in the piping C of the internal combustion engine system decreases and the waste flow rate decreases, the heat transfer coefficient U decreases.゛Also, although the temperature at the outlet of the heated fluid increases, the temperature WL difference between the heated fluid and the heated fluid (in other words, TI-t Boehm) decreases, and the numerical value of the numerator in equation (■) decreases. becomes larger, but the denominator value becomes larger than r, so the logarithmic mean temperature difference Δtm becomes smaller (this means that
+IV) can be easily derived by mathematical operations in the equation. Therefore, as the flow tG of the fluid to be heated becomes smaller, the amount of heat exchange Q also becomes smaller.

By the way, the temperature rise of the fluid to be heated is determined by the following equation as a heat wave moving in a heat exchanger having a fixed heat transfer area.

△t--9- GxΩp G: Flow rate m of the heated fluid Cp: Specific heat of the heated fluid △t; Temperature rise of the heated fluid Here, as mentioned above, the flow rate G of the heated fluid becomes small. However, since the amount of heat exchange Q also becomes small, the temperature rise Δt of the heated fluid does not increase by t'L.

In other words, even if the load on the internal combustion horizontal 26 decreases and the number of gas gutter flowing into the internal combustion engine system piping C decreases (note that the limit is
Generally, the flow rate is about ψO% of the flow rate at rated load), so that the heat exchanger 22 does not overheat. In this way, in the present invention, by using the discharged fuel gas of the pressure me as the heating fluid of the heat exchanger 22, the heat exchanger 22 has a self-adjusting ability that does not overheat. Therefore, it is possible to keep the temperature rise of the fuel gas sent to the internal combustion a26 within an allowable value without providing a temperature control device 10 such as the conventional device shown in FIG.

Furthermore, even if there is a case where the temperature rise exceeds the allowable value, the pressure range required by the internal combustion engine 26 (normal gN
By lowering the discharge pressure by /φ to /dG (gauge pressure)), the discharge temperature of the compressor 21 can be lowered, and the temperature of the fuel gas sent to the internal combustion engine 26 can be kept within an allowable value. If this situation is not explained in detail, the +11 formula mentioned in MIJ,
+1) As is clear from the formula, the discharge pressure P of compressed Mal
If d'fc- is lowered, the discharge temperature Td will also decrease. Then, the discharge pressure Pd of the compressor 21 is reduced to a pressure of 1lJI.
This can be done by lowering the set value of the J control device 80, so the set value of the pressure control
By setting it low within the required pressure range, the discharge temperature of the compressor 21 can be lowered, and as a result, the gas salt tJ of the pipe C of the internal combustion engine system can be lowered.

And changing the pressure control device 800 settings by 1 sai is as follows:
You can also do it manually. Such a change in the set value is preferably performed when there is a significant difference in the temperature of the fuel gas supplied from the gas population z9 between summer and winter. In addition, as shown in Fig. 3, there is a temperature side +fJl that detects the temperature and outputs a control signal according to the detected temperature to the piping C■ of the internal combustion engine system.
jJ, 1 pipe 86 is provided, and the setting value of the pressure control device 80 of the pipe A is changed by this control signal, and the setting value of the pressure control device 80 is automatically changed by such cascade control. You can also do this.

FIG. 9 shows another specific embodiment, in which fuel is supplied to a 40.40 λ group of gas turbines with a rating of 2.00 -. And suction pressure 103Jhtr/rJ
In order to compress the discharge pressure from A to /'1.3hy/cJ, a two-stage dynamic pressure iHd&f, 41 r 42 is provided, and a middle IHj cooing cooling 4,8, and a middle ibl mist sehalator 44 are provided. . Intermediate Cooler Shi8. And the aftercooler 28 is a brass V
It is an air-cooled type in +. The response room for the f^exchange z2 is 2 gas turbines, 2 t 00 hs, and is approximately / d, the father of 0θ0kcal/H? A two-tube type heat exchanger with a heat transfer area lφ- and a heat capacity A is used. It should be noted that the 14 minute period, which is similar to that in FIG. 2, will be marked with the same sign and its explanation will be omitted.The properties of the fuel gas used are as follows.

Ingredients 1st stage compression or 41 Solubility ratio (%) in population Methane lbg2 Ethane 7.2 g tl- Propane 22.26 Isoptane 26 Normal butane /jγ9 Normal pentane 10 Hexane 1AAc 1 Butane 69 Waterfish'AJ ,/Hydrogen sulfide? 74, Cumulative 0g Charcoal Chewing Gas /, 3V- Total 100% The results of the above fuel gas combination are as shown in each stage of Fig. 9, and the gas turbine 40 is heated to We were able to supply fuel gas.

In the above embodiment, the volume of the aftercooler 28 is as shown in FIG.
The amount of fuel gas supplied to the gas turbine 40 side is at its minimum when one gas turbine is operated without a load. The fuel gas is heat exchanger r4W722
The gas temperature at that time was 77℃.
Met. This temperature is within an acceptable range for the fuel gas sent to the gas turbine.

As explained above, in the fuel gas supply device of the present invention, n is the pressure AI? A heat exchanger that uses the discharged fuel gas of Aircraft I as the heating fluid heats the fuel gas sent to the internal combustion engine via the cooler and turns it into superheated gas. (1) A special external heat source is used. Energy savings can be achieved without the need for

(2) The f4'k of the cooler can be smaller than that of the conventional cooler.

(3) In this heat exchanger, when the flow of the fluid to be heated is reduced, the heat source provided is reduced, so to speak, the temperature is increased. ! Since the internal combustion engine has high performance, it is better not to overheat it even if the load is reduced and the fuel gas sent to the internal combustion engine becomes purer.

(φ) In the heat exchanger, the 71II hot gas and the heated gas are essentially the same, so there is no danger even if internal leakage occurs, and moreover, a small filter will adversely affect performance.
41. stomach.

Various excellent effects can be obtained. .

[Brief explanation of the drawing]

Figure j47 is a system diagram of a conventional fuel gas supply device,
Figure 3 is a system diagram showing one embodiment of the present invention, Figure 3 is a system diagram showing another embodiment, and Figure φ is a system diagram showing another practical example. 21... pressure^11 role, 26... naizen, 29... gas population (compression Tsuki sales included), 84.
85... Valve (valve), A, C... Piping (compressed fuel gas supply pipe).

Claims (1)

[Claims] In a fuel gas supply device that compresses fuel gas and sends it to an internal combustion engine, a bypass pipe connects the vicinity of the internal combustion engine of the compression/fuel gas supply pipe and the compressor suction side, and a compressed fuel gas A fuel gas supply device for a gas-burning internal combustion engine, characterized in that the fuel gas supply device is provided with a valve for causing the compressed fuel gas to flow from the compressed fuel gas supply pipe to the bypass pipe.