JPS6017542B2 - 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, the current situation is that after the disinfection is completed, the waste gas inside the disinfector is directly released 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;
A second exhaust gas that heats the post-disinfectant waste gas containing the neutralization product from the neutralization process above the sublimation temperature (230oo) of the product and then discharges it to the outside air via the platinum catalyst reactor. The reason lies in the fact that the process is carried out.

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.

Further, a duct 6 constituting an exhaust system is installed on the ceiling wall 5 of the disinfector 1, but in the example of the device shown in FIG. A blower 7, a heater 8 whose heating temperature can be adjusted using an electric heater, etc., and a platinum catalyst reactor 9 constructed by forming a platinum catalyst layer on a ceramic carrier are installed. In FIG. 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 waste gas G in the sterilizer 1 is sucked into the duct 6, and the gas G is heated by the heater 8. Gases ○,' are introduced into the platinum catalyst reactor 9. In the platinum catalytic reactor 9, formaldehyde in the initially heated waste gas ○,' is converted into HCHO+0 by using platinum as a catalyst.
2e is also oxidized to carbon dioxide and water like C02 Toka 20, rendered harmless, and discharged into the outside air from the exhaust port 6').

After the first exhaust step is completed, formaldehyde remains in the sterilizer 1 in the form of adhesion or other forms. To remove this, ammonia is injected into the sterilizer 1 from the container 3 and evaporated. By the neutralization reaction of 6N4 and LO, the neutralization product hexamethylenetetramine (
urotropin).

After the neutralization process is completed, the blower 7 and heater 8 are operated again to release the post-waste gas G2 in the sterilizer 1 to the outside air from the exhaust port 6'. In the second exhaust step, as described above, the post-exhaust gas G2 is heated to a temperature of 230 pm or higher by the heater 8, and then passed through the platinum catalyst reactor 9. In other words, the physical property of the urotropin produced by the above neutralization treatment is that it is a white, orthorhombic crystal powder and is water-repellent; This becomes mist or dust and enters the duct 6 while being mixed into the waste gas G2).

This incoming urotropin is turned into dust by drying by the heater 8, and flows into the next stage platinum catalyst reactor 9), where it adheres to the platinum catalyst and gradually accumulates over a long period of time, causing the catalytic The surface of the platinum catalyst is covered, leading to a decrease in the activity of the catalyst, and in extreme cases, the platinum catalyst layer may be blocked.

Therefore, in order to eliminate the above-mentioned defects, a filter is installed on the first stage side of the exhaust system, which can also remove urotropin. Although it is an effective means, the filter becomes clogged with use, so it is not necessary to use it frequently. Must be replaced.

Therefore, in the present invention, by heating the post-exhaust gas G2 at a predetermined temperature using the heater 8, that is, at a temperature of 23,000 or more, preferably around 250:00, urotropin is sublimed and gasified, and then the platinum catalyst It is discharged from the reactor 9 to the outside air, thereby preventing a decrease in the activity of the platinum catalyst.Of course, the residual formaldehyde in the post-exhaust gas G2 is heated and removed from the catalyst in the same way as in the first exhaust step. oxidation treatment).

In the illustrated apparatus, the above-mentioned waste gas treatment may be carried out while introducing warm air into the disinfector 1 by operating the hot air generator 4, and the blower 7 may be installed at a different position. It may be 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, formaldehyde in the waste gas is rendered harmless by catalytic oxidation in the first exhaust process, and residual formaldehyde is converted into a neutralized product by neutralization treatment with ammonia, and then in the second exhaust process, after the fact Because the waste gas is heated to over 230°C, the waste gas containing formaldehyde can be completely aerated using a simple processing device and released in a harmless state. The waste gas is heated to 250°C and treated at 250〆'hom by the method of the present invention, and the formaldehyde concentration is measured by liquid collection method, spectrophotometric analysis (acetylacetone method), and the exhaust gas is exhausted from the exhaust port 6'. ), it was less than 1 willow. Furthermore, as mentioned above, since urotropin, which is a neutralization product from the neutralization treatment, is sublimed, a filter is not necessary, and the activity of the platinum catalyst can be ensured for a long period of time.

Moreover, since the above-mentioned waste gas is heated by a heater etc. and then passed through a platinum catalyst reactor, the distribution processing capacity is also large, and even if the capacity of the formalin sterilizer is large, it is possible to detoxify it in a short time. Since the process only needs to be carried out under relatively low temperature conditions, the exhaust duct can also be constructed from a simple heat-insulating material.

[Brief explanation of the drawing]

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...Hot air generator, 7...
centre. Warmer, 8... Heater, 9... Platinum catalyst reactor, G. ...Initial waste gas, G,'...Initial heated 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 second evacuation step, and a post-exhaust gas in the sterilizer containing a neutralization product from the neutralization treatment, Formalin characterized by being heated above the sublimation temperature of the product urotropin to sublimate the urotropin, and then subjected to a second exhaust step of discharging the product to the outside air via a platinum catalyst reactor. Disinfector waste gas treatment method. 2 The heating of the waste gas in the first exhaust process and the post-heating of the waste gas in the second exhaust process are performed by a heater in the exhaust system and hot air introduced into the sterilizer from a 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.