JPS581321B2 - Liquefied gas combustion method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for atomizing and burning liquefied gas while it is in a liquid state.

Liquefied gas is usually vaporized and then combusted by a burner, but on an industrial scale, a vaporizer is generally required for vaporization, and the equipment cost is higher than in the case of normal liquid fuel.

Direct combustion of liquefied gas in liquid form eliminates the need for a vaporizer and reduces equipment costs, but there are the following problems.

(1) The amount of combustion is adjusted by installing a control valve in the burner conduit and changing the nozzle back pressure depending on the opening degree of the valve.If this pressure is lowered below the saturation pressure of the liquid, some of the liquid It evaporates and flows through the conduit as a two-phase gas-liquid flow, which causes the pressure inside the conduit to fluctuate and the gas-liquid to separate and flow out at the nozzle, which causes the flow rate to fluctuate widely, making it difficult to adjust the flow rate. It becomes difficult.

(2) The above problem can be solved by maintaining the pressure inside the conduit above the saturation pressure of the liquid, but in this case, it is necessary to maintain the pressure above the saturation pressure of the liquid even at the minimum flow rate of the liquid.
When the liquid temperature is high, such as in summer, extremely high pressure is required.

For example, butane liquid at 30℃ (saturation pressure 2Kg/cm2G)
The flow rate α to be adjusted in the range of 100 to 20%
√50Kg/cm2G is required due to pressure.

As a result, equipment and operating costs increase, and safety also deteriorates due to leakage accidents.

The present invention solves the above problems, and embodiments thereof will be described below with reference to the drawings.

A conduit line 3 that leads the liquefied gas in liquid form from the tank 1 to the burner 2
A pump 4 that increases the pressure of the liquefied gas and a control valve 5 that adjusts the amount of ejection from the burner 2 are installed in the pump 4 and the burner 5.
A liquid cooler 6 is provided in the conduit 3 between the two.

The liquid cooler 6 has a passage section for the liquid to be cooled and an evaporation section for the cooling medium via a partition wall.

A part of the liquefied gas in the conduit 3 is led to the evaporation section of the liquid cooler 6 via a branch pipe 7 branched off from the conduit 3, and is evaporated within the evaporation section or at the inlet of the evaporation section.

This heat of evaporation cools the liquefied gas in the conduit 3 to lower the liquid temperature to a predetermined temperature, and the flow rate or pressure of the cooled liquefied gas is adjusted by the regulating valve 5 and sprayed from the nozzle of the burner 2.

The gas, which has been depressurized and vaporized in the liquid cooler 6, is guided to a pilot burner 8, where it is atomized and combusted.

With this method, the liquefied gas flowing in the conduit 3 is cooled by the liquid cooling device 6, so that it can be sufficiently cooled even in summer.

Therefore, it is possible to lower the saturation pressure to near atmospheric pressure, thereby preventing evaporation within the conduit 3, and allowing the flow rate adjustment by the control valve 5 to be performed over a wide range at low pressure.

Moreover, for this reason, it is sufficient to use a small control valve 5.

For example, if a butane solution at 30°C is lowered to 5°C, the saturation pressure will be 0.3 kg/cm2G, and the maximum pressure required to adjust the flow rate from 100 to 20% may be 7.5 kg/cm2G.

Therefore, compared to the above-mentioned case where (50 kg/cm2G) is required, the risk of leakage is sufficiently lower and safety is high.

Furthermore, since the liquefied gas is cooled by evaporating a portion of it, no separate cooling medium is required, which reduces equipment costs and operating costs.

Furthermore, if the evaporated gas is used for combustion in the pilot burner 8 as in the embodiment, no energy loss occurs;
Economically advantageous.

FIG. 2 shows another embodiment in which the gas evaporated in the liquid cooler 6 is recirculated to the tank 1 via a pressurizing device 9, such as a compressor or an ejector.

Depending on the properties of the liquefied gas, it may not be completely evaporated in the liquid cooler 6 due to changes in temperature or the like.

In such a case, it is difficult to use the evaporated gas directly as fuel for the pilot burner 8 as in the embodiment shown in FIG. 1, but it is possible to eliminate waste of evaporated gas by recirculating it as in this embodiment can. In addition, although each of the above embodiments has a pump 4 for pressure increase, the pump 4 is not necessarily necessary, and the liquid cooling according to the present invention may be performed using the saturation pressure of the liquefied gas to perform spray combustion. good.

As explained above, according to the present invention, a part of the liquefied gas flowing in the conduit to the burner is evaporated in the liquid cooler, and the liquefied gas in the conduit is cooled by the heat of evaporation. There is no problem of evaporation within the passage, and the amount of ejection from the nozzle can be adjusted accurately and over a wide range.

Moreover, it is highly safe against leakage, and these features allow equipment,
Operation costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a pipeline configuration diagram showing an example of equipment for carrying out the method of the present invention, and FIG. 2 is a pipeline configuration diagram showing another example. 1... Tank, 2... Burner, 3... Conduit, 4
...Pump, 5...Control valve, 6...Liquid cooler, 7
... Turnout.

Claims (1)

[Claims] 1 In a liquefied gas combustion method in which liquefied gas in a tank is led to a burner through a conduit and then sprayed and burned in liquid form from the burner, a liquid cooler is provided in the conduit, and a part of the gas in the conduit is liquefied as described above. A liquefied gas combustion method characterized in that the liquefied gas is guided to a cooling medium evaporation section of a cooler, and evaporated under reduced pressure in this evaporation section, and the gas in the conduit is cooled by the heat of evaporation.