JPS6017541B2 - Waste gas treatment method for formalin sterilizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a waste gas treatment method for purifying a formalin sterilizer in an exhaust system for discharging the waste gas inside the sterilizer to the outside air after use.

As is known, a formalin sterilizer sprays or evaporates formalin (an aqueous solution of 35-37% formaldehyde and 0-15% methanol) onto objects to be sterilized, such as medical equipment, stored in its chamber. However, after the sterilization is completed, the waste gas inside the sterilizer is released directly into the outside air.

However, even if the above waste gas is not released in large quantities, it contains a high concentration of formaldehyde, and due to the toxicity of this substance, the permissible concentration is set to be less than 2 feet. Therefore, discharging it into the atmosphere without treatment is not desirable in terms of environmental health.

The present invention focuses on the above-mentioned pollution problem and attempts to render the waste gas harmless by treating it using a simple and appropriate method. , a first exhaust step of heating the original waste gas in the disinfector to a desired temperature and discharging it to the outside air via a platinum catalytic reactor after disinfection with injection or evaporation formalin;
a step of neutralizing formaldehyde remaining in the sterilizer with ammonia after the first exhaust step;
The waste gas in the sterilizer containing neutralization products from the neutralization process is passed through a filter for removing neutralization products, and then
After heating at a temperature of 90 oo or less, a second exhaust step is performed in which the mixture is discharged to the outside air via a platinum catalyst reactor.

To describe in detail the case where the present invention is carried out using the illustrated waste gas treatment equipment, in the equipment, reference numeral 1 indicates a sterilizer using formalin, and formalin and ammonia are supplied to the equipment from containers 2 and 3 at desired times. In addition, hot air (about 60°C) from the hot air generator 4 can be supplied to the sterilizer 1 when desired.
It is configured so that it can be sent to.

Furthermore, an exhaust system duct 6 is installed on the ceiling wall 1' of the disinfector 1 through a filter 5, but in the example of the device shown in FIG. Exit 6
A blower 7, a heater 8 whose heating temperature can be adjusted using an electric heater, etc., and a platinum catalyst reactor 9, which is constructed by forming a platinum catalyst layer on a ceramic carrier, are interposed toward . On the other hand, in Figure 2, the blower 7
is provided not at the first stage but at the final stage on the exhaust port 6' side.

Therefore, in order to implement the present invention using the above-mentioned device, the sterilizer 1
The objects to be disinfected stored in the container are disinfected by formalin supply from the container 2 in a conventional manner, and once the disinfection is completed,
By operating the blower 7 and heater 8, the initial waste gas G in the sterilizer 1 is sucked into the duct 6, the gas G is heated by the heater 81, and then this initial waste gas ○ is heated. , ' are introduced into the platinum catalyst reactor 9.

In the platinum catalytic reactor 9, the heated waste gas ○,
The formaldehyde in the air is oxidized to carbon dioxide and water using platinum as a catalyst, which is rendered harmless and discharged to the outside air from the exhaust port 6'.

Even after the first evacuation process is completed in this way, formaldehyde still remains in the sterilizer 1 in the form of adhesion or other forms, so in order to remove this, ammonia is injected into the sterilizer 1 from the container 3. It is supplied by means of evaporation, thereby producing the neutralization product hexamethylenetetramine (urotropin) through the neutralization reaction of CHO, 6N, and LO.

After the neutralization process is completed, the blower 7 and heater 8 are operated again to release the post-disinfectant gas G2 in the sterilizer 1 to the outside air from the exhaust port 6'. In the exhaust process, after the above exhaust gas G2
By passing through the filter 5, the hexamethylenetetramine, which is a white, orthorhombic crystal powder, is removed by the same filter 5, and the residual formaldehyde in the waste gas is removed after heating in the same manner as before. It is sent to the platinum catalyst reactor 9, where it is oxidized and then discharged to the outside air. As mentioned above, the heating temperature of the post-exhaust gas G2 by the heater 8 is 190 qo or less, preferably 80°C to 1
This is done in consideration of the case where the amount of ammonia used is added in excess of the amount consumed for neutralization during the formaldehyde neutralization treatment.

In other words, when NH3 is heated to a temperature of around 200°C, it is catalytically oxidized and produces toxic N○×, so in order to avoid secondary pollution caused by this NO mixture, the heating temperature is kept at 190°C or lower. It's about controlling.

In the illustrated apparatus, the above-mentioned waste gas treatment may be carried out while introducing hot air into the sterilizer 1 by operating the hot air generator 4. may be provided other than the illustrated example, and therefore may be provided on the clean air intake side (not shown) of the formalin sterilizer 1 or between the heater 8 and the platinum catalyst reactor 9.

Further, when the blower 7 is installed at the final stage as shown in FIG. 2, the inside of the exhaust system by the duct 6 becomes a negative pressure, so there is an advantage that the waste gas will not leak out from the duct 6 or the like.

As described above, in the present invention, the formaldehyde in the waste gas is initially rendered harmless through catalytic oxidation in the first exhaust step, and the remaining formaldehyde is converted into a neutralized product through neutralization treatment with ammonia, and the product is then filtered through the filter. Since a second evacuation step is also performed to remove the formaldehyde, the waste gas containing formaldehyde can be released in a nearly completely harmless state using a simple treatment device, and the formaldehyde concentration can actually be reduced to 100%. Blood waste gas is heated to 150 qC and heated to 250 qC using the method of the present invention.
The formaldehyde concentration of the exhaust gas from the exhaust port 6' was measured by a liquid collection method and an absorption photometry method (acetylacetone method), and it was found to be less than 1 skin. In addition, since the above waste gas is heated by a heater etc. and then passed through a platinum catalyst reactor, the oxidation treatment capacity is also large, even if the capacity of the formalin sterilizer is large.
It is possible to detoxify the body in a short time, and since the temperature was heated to 19,000 or less in the second exhaust process, there is no generation of N○×, and the process can be done at a relatively low temperature. It can be constructed using a simple heat-insulating material.

Furthermore, in the present invention, since urotropin is removed by a filter before the accident waste gas is sent to the platinum catalyst reactor, neutralization products are deposited on the white metal catalyst and the catalyst activity is reduced. By replacing the filter in a timely manner, you can ensure reliable exhaust gas purification performance over a long period of time.

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory front views showing various examples of processing apparatuses that can be used to carry out the waste gas processing method according to the present invention. 1...Disinfector, 4...Blower, 5.
...Filter, 8...Heater, 9...
・Platinum catalytic reactor, G, ...initial waste gas, G,'...
・Heated initial waste gas, G2...post-heated waste gas. Figure 1 Figure 2

Claims (1)

[Claims] 1. After the object to be disinfected in the disinfector is disinfected by injection or evaporation formalin, the initial waste gas in the disinfector is heated to a desired temperature and discharged to the outside air via a platinum catalyst reactor. 1st
an evacuation step, a step of neutralizing formaldehyde remaining in the sterilizer with ammonia after the first evacuation step, and a post-exhaust gas in the sterilizer containing a neutralization product from the neutralization treatment, The urotropin, which is a neutralization product, is removed through a filter for removing the urotropin,
A method for treating waste gas from a formalin sterilizer, comprising: heating at a temperature of 190° C. or lower, and then performing a second exhaust step of exhausting to the outside air via a platinum catalytic reactor. 2 The heating of the initial waste gas in the first exhaust process and the heating of the accidental waste gas in the second exhaust process are performed by the heater in the exhaust system and the warm air introduced into the sterilizer from the hot air generator. 2. A method for treating waste gas from a formalin sterilizer according to claim 1, wherein 3. The waste gas from a formalin sterilizer according to claim 1, wherein exhaust gas in the first exhaust process and the second exhaust process is performed by a blower provided at the final stage of the exhaust system. Processing method.