JPH0815530B2 - Steam regeneration method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for regenerating steam by waste heat from a solvent recovery apparatus by an activated carbon adsorption method.

[Conventional technology and its problems]

In the steam regeneration equipment of the solvent recovery device by the conventional activated carbon adsorption method, there is no waste heat from the adsorption tank during the preheating time of the adsorption tank at the initial stage of desorption, so it is not possible to regenerate the steam and it is necessary to desorb with the boiler steam. The total amount of steam is replenished.

That is, in a solvent recovery device equipped with a steam regenerating facility (ejecting method), as shown in FIG. 2, a large amount of heat is accumulated in the activated carbon in the adsorption tank 11 or 12 by the steam introduced during desorption. The accumulated heat is released to the atmosphere together with the raw gas 21 when switching from desorption to adsorption.

Then, as described above, the evaporator 16 which is the regeneration equipment is
Then, during the adsorption tank preheating time at the initial stage of desorption, where there is no waste heat from the adsorption tank 11 or 12, since the above regeneration cannot be performed, the boiler steam replenishes all the required steam.

2, 14 and 15 are raw gas inlet valves, 17 is a soft water circulation pump, 18 is a steam ejector, 19 is an exhaust gas outlet valve, and 20 is a steam supply line.

In addition, Fig. 3 shows the details of the steam regeneration facility. In FIG. 3, the same reference numerals as those in FIG. 2 have the same meanings as in FIG. 2, and reference numeral 22 denotes a soft water tank.

[Object of the Invention]

As described above, conventionally, the heat accumulated in the adsorption tank and the activated carbon during desorption was released to the atmosphere at the time of switching to adsorption, but the present invention aims to recover this heat and regenerate it as steam. And

[Means for solving problems]

The present invention has been made in order to achieve the above object, and reduces the amount of desorbed vapor by using waste heat from the adsorption tank of a solvent recovery device that alternately repeats adsorption and desorption using two or more adsorption tanks. In the method of regenerating steam for the purpose, a bypass line is provided in the raw gas line of each adsorption tank, the raw gas is supplied from the above bypass line after desorption of the adsorption tank, and accumulated in the adsorption tank and activated carbon during this desorption. The generated heat is guided to the evaporator along with this raw gas and recovered as a heat source for evaporating the soft water in the evaporator, even during the adsorption tank preheating time when there is no waste heat from the adsorption tank at the initial stage of desorption of the adsorption tank. A steam regeneration method is characterized in that steam is regenerated in order to reduce the amount of desorption steam by the recovery heat source.

[Action]

By installing the bypass line of the original gas duct, the heat accumulated during desorption is recovered by the evaporator. In addition, since the steam is regenerated during the preheating time of the adsorption tank, the regeneration time becomes longer, and the amount of heat recovered becomes larger. By increasing the capacity of the soft water circulation tank of the evaporator, sufficient regenerated steam is required. Soft water is secured.

〔Example〕

 FIG. 1 shows an embodiment of the method of the present invention.

When the desorption of the first adsorption tank 11 is completed, the raw gas 21 is gradually fed from the bypass line 31 of the original gas duct to flow the heat accumulated in the adsorption tank and the activated carbon to the evaporator 16 during the desorption (at this time, the first Adsorption tank raw gas inlet valve 14 is "fully closed", second
The adsorption tank raw gas inlet valve 15 is "fully opened" and the adsorption state continues).

In the evaporator 16, the soft water circulation pump 17 forcibly circulates the soft water and heats it to the evaporation temperature by the recovered heat. The structure of the evaporator 16 is the same as that of the conventional case shown in FIG.

After sufficiently recovering heat, the bypass valve 13 of the first adsorption tank raw gas duct bypass line 31 is “fully closed”, the first adsorption tank raw gas inlet valve 14 is “fully open” (adsorption state), and the second adsorption tank 12
Desorption is started, and the vapor evaporated in the evaporator 16 is supplied to the adsorption tank by the vapor ejector 18 even during the preheating time of the adsorption tank.

The above heat recovery cycle is shown in FIG. 4 (A) and compared with the conventional heat cycle in FIG. 4 (B).

As shown in FIG. 4 (B), conventionally, heat is recovered only by alternately repeating desorption and adsorption in the first and second adsorption tanks, but according to the method of the present invention, it is shown in FIG. 4 (A). As described above, after the desorption of the first adsorption tank, the raw gas is introduced from the bypass valve of the original gas duct (in this case, both the first and second adsorption tanks are adsorbed), and the heat accumulated in the first adsorption tank is evaporated. Collected in a container,
Then, transfer to adsorption and desorption to recover heat.

Further, FIGS. 5 (A) and 5 (B) show a comparison of the amount of boiler steam used in the solvent recovery apparatus of the method of the present invention and the conventional method. FIG. 5 (A) shows the case of the method of the present invention, and FIG. 5 (B) shows the case of the conventional method.

In FIGS. 5 (A) and (B), “a” is the boiler steam used because the raw gas is introduced from the bypass valve of the raw gas duct and the steam can be regenerated by the heat recovery in the evaporator even during the adsorption tank preliminary time. Shows the state in which the amount of steam is reduced, c shows the state in which the steam consumption of the boiler does not decrease because steam regeneration is not possible during the preheating time of the adsorption tank, and b and d show the state in which the steam consumption of the boiler decreases due to steam regeneration. ing.

As is clear from FIGS. 5 (A) and 5 (B), the method of the present invention can reduce the amount of steam by about 1/4 to 1/5 of the conventional amount.

〔The invention's effect〕

As described above, according to the present invention, the steam can be regenerated during the adsorption tank preheating time at the initial stage of desorption without waste heat from the adsorption tank, and the boiler steam consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a flow chart showing an embodiment of the method of the present invention, FIG. 2 is a flow chart showing a conventional steam regeneration, and FIG. 3 is a diagram showing an evaporator which is the steam regeneration equipment of the method of the present invention and the conventional case. The figure which shows a structure, FIG. 4 (A), (B) is a figure which compares the heat recovery cycle of this invention method (A) with the conventional case (B),
FIGS. 5 (A) and 5 (B) are diagrams showing a comparison of the amount of boiler steam used in the method (A) of the present invention and the conventional case (B). 11 …… No.1 adsorption tank, 12 …… No.2 adsorption tank, 13 …… Original gas duct bypass valve, 14 …… No.1 adsorption tank raw gas inlet valve, 15…
… No.2 adsorption tank raw gas inlet valve, 16 …… evaporator, 17 …… soft water circulation pump, 18 …… steam ejector, 19 …… exhaust gas outlet valve, 20 …… boiler steam, 21 …… raw gas, 22 …… Soft water tank, 31 …… Bypass line

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B01D 53/81

Claims (1)

[Claims] 1. A method for regenerating steam for reducing the amount of desorbed steam by utilizing waste heat from an adsorption tank of a solvent recovery apparatus that repeats adsorption and desorption alternately using two or more adsorption tanks,
A bypass line is provided in the raw gas line of each adsorption tank, and after desorption of the adsorption tank, the raw gas is supplied from the bypass line.
The heat accumulated in the adsorption tank and in the activated carbon during this desorption is guided to the evaporator along with this raw gas and recovered as a heat source for evaporating the soft water in the evaporator, from the adsorption tank at the initial stage of desorption of the adsorption tank. The steam regeneration method characterized in that the steam is regenerated in order to reduce the amount of desorption steam by the recovery heat source even during the preheating time of the adsorption tank where there is no waste heat.