Sidebilder
PDF
ePub

1

INDUSTRY'S CHALLENGE: AIR PROTECTION AND PROGRESS
Paper No. 63-AP-6, by J. 0. Julson, Weyerhaeuser Co. at Pacific Northwest

International Section of the Air Pollution Control Association
Mr. Chairman, ladies, and gentlemen, it is indeed a pleasure and an honor
to appear as a speaker during this conference, where so many experts are
giving you the benefit of their findings on this most important subject-Air
Protection. So that you will not be misled, you should know that I am not an
expert in this work. It so happens that my job has been in a plant where
protection of both air and water has always been very important to us.

On October 26, 1961, the Pacific Northwest Pollution Control Association presented to us the first award they had ever given to an industry for effective work in air and water protection. We appreciate that award, very much. The employees in the plant take strong pride in having been given this signal distinction.

Our plant is a kraft pulp and containerboard mill belonging to Weyerhaeuser Co. It is located on the eastern edge of the city of Springfield, Oreg. It is inside the city limits of Springfield.

You are well aware of the fact that a kraft pulp mill, when operating, is characterized by odors peculiar to that process.

There are no harmful health effects from those odors, but they are odors.

Dr. McCarthy of the University of Washington has found with respect to kraft mill odors that one of them is detectable by the human nose in concentrations as low as one part in a billion. The difficulty in trapping a product like that can readily be understood. Other kraft mill odors are not so potent, but nevertheless are also very difficult to contain because of the low concentrations in which they occur in the gaseous efluents from the mill stacks and vents.

When our mill was built in 1948–49 the latest devices then known were incorporated in the plant facilities, but even at that late date these devices were not too effective in preventing detectable odors from escaping to the atmosphere.

The Eugene-Springfield area in Oregon is in a valley whose floor slopes upward to the south, with ranges of mountains along the eastern and western edges. Prevailing winds generally are from the northwest to the southeast, and from the southeast to the northwest. At times shifting winds will interrupt those patterns.

In the late spring, summer, and early fall months the atmosphere is generally clear. During the rest of the year it is not unusual for the area to be covered by a cloud layer, accompanied by rain, mist, and fog. Inversions are not uncommon. It is during these times the odors are most likely to be noticed.

When the mill started production in August of 1949, the community became aware of the odor problem. During the winter months which followed, our personnel received quite numerous unfavorable comments and complaints from the neighbors in the area. My knowledge on that is secondhand since I did not arrive on the west coast until June 1950. But, when I arrived, plant people briefed me quite fully on the situation and showed me communications which had been received registering complaints about the odors. The most effective were valentines received on February 14, 1950, one of which said simply: "You stink.” This was a very effective “billet-doux," to say the least. I am told that our Weyerhaeuser people did not exactly see the humor in those communications, but I do know that the message had been receivedloud and clear.

When I arrived, my new boss told me that he considered the most important tasks I had facing me were corrections of the atmospheric odor problems and to insure that the McKenzie River water would not be harmed. That message also came through--loud and clear. I have never forgotten it, nor have I permitted personnel in the plant to forget it.

I shall mention only briefly that protective steps were taken in preventing harm to the McKenzie. Those steps were not taken overnight—it was a long and arduous job, but it was done and done quite successfully. Through this series of steps, we have done a job that has been to the complete satisfaction of the Oregon State Sanitary Authority, who, it should be added, were very helpful to us. We are very proud of this accomplishment, and we are jealous of the work done to such point that we do not intend to let emphasis slacken in any way on this protective program.

Since the subject today deals with air protection, most of the rest of this discussion will be confined to that alone.

The directive which my boss had given me was not born of the moment, nor really because of the valentines received. Weyerhaeuser had already spent a considerable effort in the attempt to prevent the need for such communications. This effort was by the research people in the company and by the installation of corrective facilities. Obviously, that effort had not been enough. Weyerhaeuser was aware of that just as soon as the plant started operating. As you can imagine, further corrective steps in this protective activity also could not be taken overnight. Other methods would have to be devised and tried out. I shall enumerate only the most important of these.

We shall always feel that the most important protective "gadget” is something that cannot be researched, designed, built, or bought. This "gadget” is a frame of mind and can perhaps be best described by a single word-attitude. The attitude could have been taken that correction was impossible; the attitude taken was that correction was possible. We proceeded on this latter basis.

Research and plant personnel then immediately set to work on projects to try. The first to come to mind was oxidation of the black liquor before burning it in the recovery furnaces. There were two reasons for adopting this as the first effort:

1. This idea had been suggested as a possible correction by other scientists in the industry who had been working on the problem.

2. We were installing a facility for another purpose, but whose design was such that it could be used as a pilot plant to determine the possibility of oxidizing the black liquor and to measure the benefits therefrom, if any.

This facility was converted over. The results were very promising. One feature in our favor was that the black liquor produced in our plant had very little tendency to foam during the oxidation process and the liquor did oxidize readily. Briefly, oxidized black liquor has less tendency to release sulfur during the burning operation, thereby lowering the tendency to form hydrogen sulfide, an odorous gas. Reduction of odor from the furnaces was qui noticeable. We therefore proceeded to a full scale installation of oxidation towers, and are using them today.

The effect was so noticeable to the community that we had numerous comments along this line: "What have you done to eliminate the odor?" Actually, the odors had not been completely eliminated (they aren't even today), but the relative difference apparently was so great that people did make many comments like that mentioned. We were quite happy about this.

We know that odors still escaped-odors which were not pleasant even though they had become less noticeable. We knew that they could be problems during times of inversions and “heavy" atmospheric conditions.

The next step was to see if odor emissions would be lessened if we could carry an excess of air in the recovery furnaces and in the lime kilns. Our research people had developed special techniques which could be used to measure the changes in odors in the presence of excess air. We found that it does help reduce obnoxious odor output if excess air is carried. We now do this at all times in the lime kilns and whenever possible in the recovery furnaces. This step also was beneficial, but not as noticeable to the community.

The next step was very beneficial. This was the burning of blow and relief digester noncondensable gases. These noncondensable gases are very odorous. The trick was to collect and burn them, yet avoid explosions. We had attempted it several times, but the explosions were so severe that we had to abandon the trials. Two events made it possible for us to renew our efforts :

1. Work done by Mead ('orn in their plant at Macon. Ga.

2. Finding some surplus World War II barrage balloons. The two items don't seem to be related, but for us a relationship did develop.

Speaking first of Mead Corp. efforts. they had developed a special furnace and protective devices which enabled them to burn relief ga ses. They sent us their design details and we installed a duplicate arrangement. It worked quite well. We used it for a while. but were not satisfied because of the danger from explosions, which still existed. and the fact that we could not handle digester blou gases.

Again. the Research Department came to our rescue. They dreamed up the idea of installing a gas holder which could receive the gases as generated and yet be able to meter the gases to a fire at a uniform rate. If this could

be done, it would be relatively simple to avoid explosive mixtures in the system. World War II barrage balloons were still available. Three were procured, suspended on end, and connected to the gas collecting piping system. The results were very good-much better than we had anticipated. The total gas rush was much lower than we had thought, and metering the flow to the fire was easy. The trial resulted in the installation of the vaporsphere, a spherical steel tank inside of which an impervious diaphragm rises and falls as the gas enters and leaves. The gases are burned in the kilns.

Once again people asked: “What have you done to eliminate the odor?" The community effects were good. Again, we were pleased with the results obtained.

We have done other work, but these are the major efforts. We do not pretend that our mill operates without the emission of odors. We do know that the intensity of odors released has been reduced so much that we now rarely have complaints about the odors from the plant. This could be due in part to the fact that the community has recognized the fact that progress has been made and that more progress will be made when we know how to make it in a practical manner.

I would like to return to the first step_creation of a proper attitude. I believe this to be the most important nee in any program like this. The employees in the mill are very proud of the progress made in reducing odors and protecting the river. They all are very alert to anything that can be out of control. Steps are taken immediately to correct whatever is wrong at the moment. They know, better than anyone else, that the mill can be run properly, and they want to see it run properly. I firmly believe that without this type of attitude it would be difficult, if not impossible, to do what has been done at Springfield.

It is my opinion that all people have to develop this type of attitude toward air and water. The old clunker spewing oil and unburned gasoline fumes out on the highway, the farmer burning his fields, and the neighbor operating a smoky oil burner, are but examples of how we all will have to take a more responsible attitude to stop these practices. Protection of water from careless actions by all individuals will be necessary to improve water quality-this means individuals as well as industries, business, and governmental units. Everyone is guilty of harming the waters, more or less. As Chet Huntley once said : “The trouble with water is people.” He can also say: "The trouble with air is people.”

I do not believe we need the Federal Government to enforce air and water protection programs. We will be better off-far better off—if we follow this type of a schedule:

1. The Federal Government has a very important role to play in research, survey, and study programs. The information developed would be used by State and local governments to plan their own standards and enforcement thereof.

2. State and local governments should establish proper standards, and then provide regulations for the enforcement of those standards.

3. Governmental units, businesses, industries, and individuals will have to develop more responsible attitudes and take the steps necessary to comply with State and local regulations.

Air and water are too valuable and too necessary to everyone to permit their wanton abuse.

As individuals and entities, we are obliged to cooperate with State and local agencies in developing workable standards and enforcement regulations. I believe this to be much better than sitting idle until the Federal Government has to take over. That is not desirable, nor is it necessary. I do not need to remind any of you that, if you want to control your own affairs in the manner best suited to your needs, you must do this now-in this and in all areas where Government is concerned.

It has been my very great pleasure to be with you today. We in Weverhaeuser hope that the example cited herein will stimulate all of you to take the position that a protective job can be done the only thing required is that we all get busy and do it. Thank you.

The CHAIRMAN. Peter, do any of you three gentlemen want to summarize further? Let me say this, in addition, you have asked this committee for help, so let me tell you exactly what the committee is in a position to do, and what it isn't, because I think that ought to be clear, too. In the first place, the Clean Air Act provides the research money and the program money that can be used for research purposes by the communities or by the State, so in order to take advantage of this part of the Clean Air Act, you would have to do something at the legislative level in May, because this Clean Air Act cannot operate in this respect without implementing legislation on the State level.

Now, so far as the enforcement provisions of the Clean Air Act are concerned, here too, the Federal Government cannot act except upon the request of the State government through the Governor; and since there are no standards up there to be applied to this particular problem, an enforcement action would be difficult at the

very

best. So, I thought I ought to spell out exactly what we are in a position to do, and not to do. I think principally what this committee can do is to be helpful, is to put together a complete record which the company can help us to do; and if we can get the record complete, then we can get some idea where to go from there. Any further comments?

Mr. Briola. I suggest the solutions in Mr. Kenline's report to the U.S. Public Health Service will be helpful. They appear on page 36 of that report.

The CHAIRMAN. We will have printed in the record at this point, that portion of the Berlin, N.H., report which is entitled, “Solving the Problem," on page 36, and that will give us some of the information I asked for here and it can be supplemented by the company at such time as it is in a position to do so.

(The excerpt is as follows:)

SOLVING THE PROBLEM Emissions from other than industrial processes are not of sufficient magnitude to warrant consideration of control measures for these sources. Improvement in air quality can result from solving the problem of industrial emissions. Of immediate concern and obvious notice are emissions of particulates, sulfur dioxide, hydrogen sulfied and organic sulfur gases, and odors. Principal sources are sulfate pulping operations, MGO recovery and sulfite operations, and steamraising operations.

SULFATE PULPING OPERATIONS Solutions to some of the air pollution problems facing the industry do not come easily. Is it possible to build and operate a completely odorless kraft mill? The answer to this question is only partly a technical one. Technically the answer is that compeltely ordorless mill is possible if management is prepared to pay the price. A preliminary consideration of the technical problems suggests that the direct costs of a complete odor control system would not be excessive nor would they all be pure outgo. Particulate emission

Particulate emissions originate largely from the recovery furnace, smelt tank, and lime kiln.

The dust content of the furnace gas is fairly great, in the order of 100 pounds per ton of pulp produced ; it is normally made up of minute particles less than 1 micron in diameter. The installation of an electrostatic precipitator, which is an economic necessity to the operation of a kraft pulpmill, removes about 85 to 95 percent of this material. The balance of the dust escapes to the atmosphere. During its passage through the precipitator, the dust is largely flocculated so that this material that escapes consists largely of fluffy aggregates up to 1 millimeter in diameter and of fine particles comparable to ordinary industrial smoke. It is mainly the large aggregates that settle out within a mile or two of the stack, and there, contribute to the overall dustfall and damage paint and vegetation. To improve recovery of saltcake from this source (and reduce atmospheric emissions), secondary scrubbers, following the precipitator, have been installed in some instances. An added dividend is obtained since these scrubbers also collect some gaseous material. Venturi scrubbers and spray-type washers are popular secondary scrubbers, and weak black liquor or water is used as the scrubbing medium. Some effective demister is required after the scrubber; this may take the form of a tall stack. Secondary scrubbers installed in mills reportedly perform satisfactorily. Present particulate emissions from recovery furnaces in Berlin amount to over a ton per day; use of a secondary scrubber should easily reduce this and also recover perhaps 0.5 ton of saltcake per day.

The smelt dissolving tank stack is equipped with a water spray; emissions from this source amount to 65 pounds per hour at a loading of 0.4 grain per cubic foot. Most of this is undoubtedly mist carryover. Mesh demisters may be effective in reducing this emission. At one installation it was reported that 99 percent of all droplets over 5 microns were recovered.

Emissions to the atmosphere from the lime kiln amount to 100 pounds per hour at a loading of 0.6 grain per cubic foot. This is about par for the source as compared to values reported in the literature. The lime kiln stack in Berlin is equipped with water sprays of unknown operating conditions and efficiencies. The dust from lime kilns has been a major nuisance of sulfate mills, and it is remarkable that the problem of collection of these relatively large particles has not been thoroughly investigated. Collins reports that efficiencies of approximately 99 percent removal of lime dust are achieved at relatively low pressure drops with a modification of a venturi scrubber. Vigilance in maintenance and operation of the present sprays may lead to decreased emissions. It is suggested that the efficiency of the water sprays be checked by sampling upstream and downstream from the washer; efficiencies should run 80 to 85 percent, and if less than this, some maintenance or alteration is called for. Odor emission

As has been stated, major sources of odor are digester gases, evaporator gases, and furnace gases. In addition a number of sources of lesser magnitude exist.

Elimination of odors from digester gases can be accomplished by collection and oxidation of blow gases and relief gases. The most satisfactory means of collection apparently is removal of the condensable fractions followed by storage of the noncondensables in a floating cover or diaphragm gas holder. Oxidation of the collected gases is accomplished by burning in the lime kiln or in special furnaces, or by mixing the gases with effluent from the bleach plant.

Oxidation of black liquor before evaporating and burning prevents the formation of many of the odorous compounds otherwise released. Sulfur losses from the evaporators are reduced by more than 90 percent, and odors are very greatly curtailed. Odors from the recovery furnace also are reduced. Better liquor burning in the furnace may also be achieved.

In most sulfate mills improved design and improved operation of the recovery furnace can pay big dividends. Adequate secondary air and sufficiently high temperatures can result in greater heat recovery, reduction in odor emission, and reduction in sulfur losses. Improved operation of the furnace also reduces the emission of hydrogen sulfide.

MGO RECOVERY

Emission of sulfur dioxide from the MGO stack, as evidenced by measurement, observation, and vegetation damage, is of sufficient magnitude to require investigation into control measures. The flue gas from the boiler contains ( 8 percent sulfur; it is essential to the economic operation of the system that this sulfur be recovered. The present recovery system should be adequate for recovering the sulfur dioxide from the flue gas. Excessive emissions of the gas may be due to improper operation or gross systems failure. Additional control equipment should disclose the reason for the emission, and corrective action should be taken.

BOILER PLANT Particulates

The boiler plant constitutes the major source of particulate emissions. Control of this source would materially reduce dustfall in Berlin. The control of

30-083 064431

« ForrigeFortsett »