JP2853210B2 - Soft water production equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a soft water producing apparatus for a soft water feed water boiler using an ion exchange membrane, and more particularly to a soft water producing apparatus using a Donan membrane dialysis apparatus.

[Conventional technology]

2. Description of the Related Art Conventionally, as a soft water producing device for a soft water feed water boiler, a soft water producing device that captures hardness components such as Ca ²⁺ and Mg ^{2+ in} raw water with a Na-type cation exchange resin and softens the water has been used.

Such a soft water producing apparatus ion-exchanges Na ⁺ in the Na type cation exchange resin with Ca ²⁺ or Mg ²⁺ in the raw water to produce soft water, so that the cation exchange resin is Ca ²⁺ or Mg ^When saturated with ^2+, it is necessary to temporarily suspend softening and supply a regenerant such as a NaCl solution to regenerate the cation exchange resin into the Na form.

This regenerating operation is troublesome, requires replenishment of the regenerating agent even when performing automatic regenerating, and there is a possibility that a trouble such as forgetting to insert the regenerating agent may occur. In addition, since the softening process is interrupted by the regeneration operation, soft water cannot be produced continuously.To continuously supply soft water to the boiler, a tank for storing soft water to be supplied during the regeneration operation is required. Required. Further, a special agent is required as a regenerating agent.

[Problems to be solved by the invention]

An object of the present invention is to solve the above-mentioned problems, a soft water can be continuously produced, a special regeneration step performed by interrupting the softening step, and a soft water that can reduce the production cost without requiring a special regeneration agent. An object is to provide a manufacturing apparatus.

[Means for solving the problem]

The present invention provides a liquid chamber to be treated and a regenerating agent chamber partitioned by a cation exchange membrane, a flow path for guiding raw water to the liquid processing chamber, and a flow path for supplying softened water from the liquid processing chamber to the boiler,
A soft water producing apparatus having a flow path for guiding blow water from a boiler to the regenerating agent chamber.

As the raw water used in the present invention, water containing a hardness component generally supplied to a boiler, such as tap water, industrial water, river water, and well water containing a hardness component, can be used.

The regenerant used in the present invention is blow water blown during operation of the boiler to keep the concentration of the boiler water constant. This blow water depends on the blow rate, but usually
It has an alkali metal ion concentration about 20 times that of raw water. In the present invention, blow water having a concentration gradient such that the alkali metal ions of the blow water and the hardness component in the raw water can be dialyzed through a cation exchange membrane using a Donan membrane,
Those satisfying the following expression (1) are preferable.

[Operation] In the soft water producing apparatus of the present invention, raw water containing a hardness component such as Ca ²⁺ or Mg ²⁺ is supplied to the liquid chamber to be treated, and blow water of a boiler containing alkali metal ions at a high concentration is used as a regenerating agent. The solution is supplied to the chamber, and the Donane membrane dialysis is performed through a cation exchange membrane that separates the liquid chamber to be treated and the regenerant chamber. At this time, the hardness component in the raw water is dialyzed toward the regenerating agent chamber, and the alkali metal ions in the blow water are dialyzed toward the liquid chamber to be treated, so that the raw water is softened. Then, the softened water is supplied to the boiler as a supply, and the blown water, which has been concentrated and has an increased alkali metal ion concentration, is led to a regenerating agent of a softening water producing apparatus and used as a regenerating agent.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a system diagram of a soft water producing apparatus according to an embodiment, and FIG. 2 is an exploded perspective view of the soft water producing apparatus.

In the figure, 1 is a soft water production device, and 2 is a boiler.
In the soft water producing apparatus 1, the liquid chamber 3 to be treated and the regenerating agent chamber 4 are separated by a cation exchange membrane 5. The liquid chamber 3 and the regenerating agent chamber 4 are formed by spacers 5a and 5b, and end plates 6a and 6b are arranged at both ends and fastened by bolts 7 and nuts 8. In FIGS. 1 and 2, only one unit of the liquid chamber 3 and the regenerating agent chamber 4 is shown for easy understanding, but in reality, many of these units are stacked side by side.

Each spacer 5a, 5b has an inflow hole 9a, 9b and an outflow hole 10
a and 10b are provided. The inflow hole 9a of the liquid chamber 3 to be treated communicates with the raw water pipe 11, and the outflow hole 10a of the liquid chamber 3 to be treated is connected to the water supply pipe 12.
To boiler 2. The inflow hole 9b of the regenerating agent chamber 4 is connected to the boiler 2 by a blow water pipe 13, and the outflow hole 10b of the regenerating agent chamber 4 is connected to a drain pipe 14. The liquid chamber 3 and the regenerating agent chamber 4 are of a co-current type, but may be of a counter-current type or a cross-current type.

In the boiler 2, soft water is supplied from a water supply pipe 12, and steam is taken out from a steam pipe 15, and a part of the steam is condensed from a load 16,
The water is circulated to the boiler 2 through the condensing pipe 17 together with the soft water of the water supply pipe 12. Also, in order to keep the concentration of water in the boiler 2 constant, a part of the boiler water is taken out as blow water and supplied from the blow water pipe 13 to the regenerant chamber 4 of the soft water producing apparatus 1 as a regenerant. ing.

In such a soft water producing apparatus, raw water containing a hardness component such as Ca ²⁺ and Mg ²⁺ is supplied from the raw water pipe 11 to the liquid chamber 3 to be treated,
The blow water of the boiler 2 containing a large amount of alkali metal ions is supplied from the blow water pipe 13 to the regenerating agent chamber 4 for softening. At this time, since the alkali metal ion concentration of the blow water is high, the cation exchange membrane becomes an alkali metal ion (Na) type,
Since the hardness component in the raw water has higher selectivity, ion exchange is performed. Then, the cation exchange membrane whose hardness components have been exchanged is regenerated with blow water to be of an alkali metal ion type. As a result, Donan membrane dialysis is performed using the concentration gradient of each ion as a driving force. For this reason, the hardness component in the raw water is dialyzed toward the regenerating agent chamber 4 and the alkali metal ions in the blow water are dialyzed toward the liquid chamber 3 to be treated. As a result, the raw water is softened. Then, the soft water is supplied from the water supply pipe 12 to the boiler 2 and becomes steam, and the blow water of the boiler 2 is supplied from the blow water pipe 13 to the regenerating agent chamber 4, used as a regenerant, and discharged from the drain pipe 14.

In such a soft water producing apparatus 1, ion exchange (softening) is performed.
And regeneration are performed in parallel and continuously, so that the blow water of the boiler 2 discharged continuously can be continuously used as a regenerant, and the softening process for regeneration can be interrupted, or the soft water or blow water can be stored. No tank is required. This eliminates the need for a special regeneration step or a special regeneration agent that is performed by interrupting the softening step, and enables continuous production of soft water at low cost.

 Next, test examples will be described.

Test Example Using a soft water production apparatus as shown in FIGS. 1 and 2, a strong acid cation exchange membrane Selemion CMV (trade name) manufactured by Asahi Glass Co., Ltd. was used as the cation exchange membrane, and operated under the following conditions. Soft water was produced.

Raw water: Atsugi city water (water quality is shown in Table 1) Blow water: Na concentration: 0.027N (blow rate: about 5%) Flow rate: Raw water: 1.4 ml / min Softener: 0.07 ml / min ··· Countercurrent membrane area · · 114 cm ^{2 The} concentration of cations (Na, K, Mg, Ca) in the obtained soft water was measured by an atomic absorption method. The sampling of soft water was performed after the total equivalent of Ca ²⁺ and Mg ^{2+ in} the loaded raw water exceeded the exchange capacity of the cation exchange membrane.

The analysis result of soft water is as shown in Table 1. Hardness component 1mg / (as CaCO ₃ ) which is the target of general soft water feed water boiler
Was obtained.

[Effects of the Invention] In the present invention, raw water is subjected to Donan membrane dialysis using boiler blow water as a regenerant, so that soft water can be continuously produced,
Thus, a soft water producing apparatus which does not require a special regeneration step or a special regenerating agent for interrupting softening and can reduce the production cost can be obtained.

[Brief description of the drawings]

FIG. 1 is a system diagram of a soft water producing apparatus according to an embodiment, and FIG. 2 is an exploded perspective view thereof. In each figure, the same reference numerals indicate the same or corresponding parts, 1 is a soft water producing apparatus, 2 is a boiler, 3 is a liquid chamber to be treated, 4 is a regenerant chamber, 5 is a cation exchange membrane, 11 is a raw water pipe, and 12 is a raw water pipe. Water pipe, 13
Is a blow water pipe.

Claims (1)

(57) [Claims] 1. A liquid chamber to be treated and a regenerating agent chamber partitioned by a cation exchange membrane, a flow path for leading raw water to the liquid chamber, and a flow path for supplying softened water from the liquid chamber to the boiler. ,
A soft water producing apparatus having a flow path for guiding blow water from the boiler to the regenerating agent chamber.