JPS58109102A - Evaporator - Google Patents

Abstract

PURPOSE:To decrease the discharging rate of steam, to prevent the decrease in efficiency, and to make the suction rate of a steam bleeder adequate by providing plural gas venting ports of different heights on the heating side of an evaporator, and bleeding steam mainly from the gas venting port which is lowest above the liquid level. CONSTITUTION:In order to set the rate of evaporation (evaporating capacity) of an evaporator 1 at a prescribed value, a water level is set in a control mechanism 8. In the stage of changing the evaporating capacity of the evaporator 1, the level of the condensed liquid is changed to comply with load capacity by the mechanism 8. In this time, gas vent valves 21, 21', 21'' are controlled by the liquid level control mechanism in the mechanism 8. For example, in the case of raising the level of the condensed liquid from the lowermost position, the gas vent valves that submerge the liquid level are closed so that the gas vent valves which are lowest above the liquid level are always opened. Since there is some air that is blown upward in the evaporator 1 and arrives at the upper part, this air is bled through a gas vent port 20.

Description

[Detailed description of the invention] The present invention relates to an evaporator using an evaporator.

If condensate is stored on the heating side of the evaporator,
#[ff'Y The separated air is extracted from the heating side through the gas vent port, but if the liquid level fluctuates, if there is only one gas vent port, it must be provided at the highest position. Air is heavier than steam, so it accumulates at the bottom, and if the liquid gap is low, a considerable amount of the supplied steam will be extracted and exhausted from the gas vent, reducing efficiency and increasing the suction amount of the extraction device. There were drawbacks that caused problems.

The present invention eliminates the above-mentioned drawbacks of the conventional method and reduces the amount of steam discharged by providing a plurality of gas venting ports with different heights and using only the lowest gas venting port above the liquid level as the main gas venting port. It is an object of the present invention to provide an evaporation device that prevents a decrease in efficiency by reducing the amount of oil and gas, and allows the suction amount of the oil and gas device to be appropriate.

The present invention provides an evaporator using an evaporator, in which a plurality of gas vents on the heating side are provided at different heights, and the liquid level of the condensate stored in the heating side changes. This evaporator is characterized in that only the gas venting port above the liquid level and closest to the liquid level is opened as the main gas venting outlet.

The present invention will be described with reference to the drawings, in which 1 is an evaporator, 2 is an inflow of raw liquid, 3 is an outlet for concentrated liquid,
4 is a steam inlet, b is a steam outlet, 6 is a condensate outlet, and 7 is a pump.

Control of the evaporation capacity of the evaporator I will be described.

Condensed liquid is stored on the heating side of the evaporator l. The control mechanism 8 includes a flow rate control mechanism that detects the flow rate of condensate discharged from the pump and operates the regulating valve 9Y to control the flow rate to match the set flow rate, and a flow rate control mechanism that detects the level of condensate stored on the heating side of the evaporator 1. It is equipped with a water level control mechanism that controls the condensate level by changing the set flow rate of the flow rate control mechanism and operating the regulating valve 9 so that the condensate level matches the set water level determined according to the load.

In the structure of this embodiment, when a steady state is reached for the given load, the evaporation amount of the evaporator 1 matches the condensation amount, so the evaporation amount (evaporation capacity) of the evaporator 1 is adjusted to a predetermined value. In order to set the value, the control mechanism 8 may set the condensate discharge flow rate of the pump 7, that is, the opening degree of the regulating valve 9.

On the other hand, by changing the water level of the condensate in the evaporator 1, the heat transfer area changes and the amount of evaporation can be changed. In order to set the water level, the water level is set in the control mechanism 8.

When changing the evaporation capacity of the evaporator 1', the required evaporation amount (=condensate discharge flow rate) in the control mechanism 8 is set, for example, in the central control room. When the discharge flow rate of the pump 7 is detected and a difference from the set flow rate is found, an instruction to change the water level is given to the water level control mechanism, and an instruction is further given to the regulating valve 9 to return the flow rate to the set value, and the current The water level on the molten metal surface will match the load capacity.

For example, if you want to lower the evaporation capacity, lower the flow rate setting,
The flow rate control mechanism issues an instruction to the water level control mechanism to raise the water level, and the water level control mechanism throttles the regulating valve 9, reducing the flow rate flowing through the pump VV*, raising the water level, and reducing the heat transfer area. This reduces the amount of evaporation. To increase the evaporation capacity, the reverse operation is performed.

In the control mechanism 8, by combining a water level control mechanism in addition to a flow rate control mechanism, the water level (i.e., heat transfer area) can be confirmed, and the water level can be detected for performing gas venting control as described below. This enables safe and reliable evaporation capacity control.

If such load control is performed, other evaporators will not be affected, and the load can be easily finely adjusted.

The evaporator 1 has two passes, and the liquid t'lk of the heat exchanger tube 14 is increased to prevent the liquid film from being cut. A partition plate 17 is provided in the liquid supply section 1B and the liquid drain section 16, respectively.
There is an opening 1g in the center of the partition plate 18 of the liquid drawer 1B15 so that the evaporated pH can be separated.

20 is a gas vent, 21. ! 1' and 21' are gas vent valves that serve as main gas vent ports, and are provided at different heights. Reference numeral 22 is a gas venting pipe connected to the oil/air system. The gas vent valves 21° 21', 21'' are controlled by the liquid level control mechanism 8 in the control mechanism 8. For example,
When the condensate level rises from the lowest level, the vent valve below the liquid level is closed, but the lowest vent valve above the liquid level is always open. Therefore, when the liquid level falls, when the mouth of the gas vent valve appears above the liquid level, the gas vent valve is opened. After separating the condensate, the air accumulates at the bottom of the evaporator, so vent the gas from the bottom as much as possible. If the upper gas vent valve is always open, the steam entering from the steam port 4 will escape directly, reducing efficiency and causing the suction amount of the oil/air system to become excessive, which can be prevented. Since some air is blown up in the evaporator 1 and reaches the upper part, a gas vent 10 is provided to extract this air.

As the evaporator 1, it is preferable to use a thin film falling evaporator (FFE).

The present invention provides an evaporator using an evaporator, in which a plurality of gas vent ports on the heating side are provided at different heights, and when the liquid level of the condensate stored in the heating side changes, the liquid By opening only the gas venting port above the surface and closest to the liquid surface as the main gas venting outlet, it is possible to provide an evaporator that prevents a decrease in efficiency and prevents an excessive intake amount of the oil/air system. This has a very large practical effect.

[Brief explanation of drawings]

The drawing is a flow diagram for an embodiment of the invention. 1... Evaporator, 2... Raw solution inlet, 3
...Concentrate outlet, number...Steam inlet, 6
...Steam outlet, 6...Exit, fu...
...Pump, S...Control mechanism, 9...
・Adjusting valve, 14...Heat transfer tube, 15...
Liquid supply section, 16...Liquid extraction section, 17...
・Partition plate, 18...Partition plate, 19...
Opening, 20... Gas venting port, 21, 21'. 21... Gas vent valve, 22... Gas vent pipe. Patent applicant: Ebara Corporation

Claims (1)

[Claims] 1. In an evaporator using an evaporator, when a plurality of gas vents on the heating side are provided at different heights and the liquid level of the condensate stored in the heating side changes, the liquid level An evaporator 0 characterized in that only the gas venting port located above and closest to the liquid surface is opened as the main gas venting port.