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You want Control? Burner Control? Here, have some Control!

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Last summer, we offered several asphalt mix producers in an area, a site visit to train their people while auditing the status of their operation and as a bonus, fixing problems we had the resources to fix while we were there.

 

For Flinn Paving, we not only identified problems with their combustion, we fixed them. Whereas, others before us tried to reduce the incomplete combustion, we stuck with fixing it until we did. What made this fix difficult to pin point was the fact that they had two different things contributing to the problem. Material was falling through the flame and the air to fuel arrangement on the burner was set too rich. Both resulted in reading extremely high Carbon Monoxide readings at the stack. Once these two issues were resolved, that burner roared like never before. The combustion intensity at their normal burner position was so great, the burner position was lowered significantly. In so many word, it took less fuel to heat and dry their aggregate.

 

Our analyzer was showing we were burning nearly all the carbon. As a result, the owner was now working on a positive cash flow that was not available to them before. Saving money is somewhat like a revenue stream.

 

Controls have evolved since this combustion system was put in place. Matt, the owner, wanted better mix temperature control. With an Automatic Damper control, we could maintain the best burner efficiency possible. With better safety interlocks, we could protect personnel and the equipment much better. And so, we built him a system specifically for his needs.

Over the years, older equipment gets hard to maintain because they are outdated and parts are not readily available. And as funny as it seems, Burner Controls and Damper Controls are usually not run in Automatic. The typical, justifiable excuse I hear from plant operators are that the controls over shoot the set point excessively or just don’t work.

Plant Manager, Scott Cartmill, was running his plant with controls that were not designed to be a Baghouse High Temperature Limit. The aggregate temperature was not automatically controlled. The exhaust damper would constantly hunt for set point because the damper actuator control was too sensitive and there was no way to desensitize it.

Plant Operators should not be babysitting adjustments that can be easily replaced with Automation. Plant operators should have a clear mind for other important things they do. Babysitting processes adds to their stress and adds distraction.

The trick is to set the control so it will make small adjustments so as not to over shoot the set point yet fast enough to keep up with process changes.

Many plants have a damper control that uses a Duff Norton Actuator controlled by a Dwyer Photo-Helic (sensitive vacuum switch) . The actuator moves too fast for the delayed correction to be measured by the Photo-Helic.  Consequently, the system will hunt. This forces the operator to place his Damper Control Mode to Manual. The draft wanders around when the operator is not babysitting it and fuel is being wasted and this causes material temperature changes. FYI The Draft Set Point is best determined during a burner tune up.  Until that has been determined, the operator should experiment with finding the best draft setting by comparing different settings with the highest material temperature. This is should be in your SOP (Standard Operational Procedure).

Our upgrade included that the Exhaust Damper and Burner Control Valves were provided with valve position indicators. During startup, this is allowing the operator to anticipate where to set these valves at without having to wait for the system to respond.

Many of the older burners had one limit switch to help determine that the mechanical firing rate control on the burner was in a low fire position. Much like making sure your foot is off the gas pedal when you start the car. We do not want High Fire Heat to be roaring down the drum to the baghouse. There are two components necessary that need to be in sync with each other, the gas valve and the burner air damper valve.

 

Our upgrade included that we placed a limit switch on both of those. Plaant Mechanic KevinKesselberg simply took a small sheave with a bore diameter that would fit over each valve shaft  end and then tightened the set screw in a position to make the limit arm actuate the switch when the valves reached the Low Fire Position. We not only electrically tied these two limits in series to the Pilot Solenoid Valve, we wired them to an indicator light (Low Fire Position) on the Panel so we can cross check it’s proper operation every time we light up and shutdown. We used single pole limit switches to energize a double pole relay in order to accomplish this.

.Also, to protect the baghouse, we included a High Temperature Limit, UL Approved as a High Temperature Limit in the inlet. A very important improvement.

The Stack did not have a temperature readout. We added one.  In the morning, it’s nice to know when your baghouse is warm enough to run. As you are running, you are expecting the baghouse to run with appropriate temperature drop. You won’t know that without Baghouse In and Baghouse Stack temperature readings. Too big of a temperature drop tells a story of why you all of a sudden lost some of your production rate. Any guesses what may have caused that?

 

Scott was having problems with his Aggregate Temperature reading low. After eliminating all the problems that we felt it could be, it dawned on us that much of the thermocouple body was exposed to cooler outside air. Although the Thermocouple Tip was exposed to the hot aggregate, the cooler pipe shaft was dragging the aggregate temperature reading down 80 degrees. We mounted the thermocouple so the shaft was being warmed up to temperature in the chute. Since the shaft is of softer steel material, we protected it with an angle iron to keep it from wearing out.

And finally, one of the most important things Flinn Paving benefitted from was that their people understood more about the process and the instrumentation. If you were an airline pilot, you would have to be Instrument Rated in order to fly a plane through the clouds to the airport below with nothing but your instruments. Scott Cartmill and Joe Griffin are now Instrument Rated to land that jumbo jet.

Matt Flinn has always put training for his people at the top of his list. Matt has been one of our best patrons to our training. If you want a sampling of the training they receive, please sample what we have to offer.

http://clarencerichard.adobeconnect.com/electro-mech-demo

http://clarencerichard.adobeconnect.com/workshopdemo

As you can see, I’ve been doing all the talking. If you care to contribute or debate an issue, please register. I look forward to facilitating a forum where new ideas are always forth coming.

Until we meet again, I hope the stars are aligned in your favor.

Clarence

Let’s educate your Safety Director and Fire Department and Rescuers.

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Let’s educate your Safety Director and Fire Department and Rescuers.  

What did I get to do this week? I reflected on the Safety Program we developed and how to use it. I do not think we are using our Safety Programs to their potential. If you look at our history, every time one of our companies have a bad accident or injury or fatality, we look at why the safety interlocks were not working and we look at why our safety program failed. Then we made the correction. It is a little like closing the barn door after the cows got out. It is like buying high and selling low.

I have moderated many a safety meetings for corporations resulting in very little impact. The reason there was such little impact is that the owners and their safety directors were not involved. I find it that Safety Directors do not seek us out. Most Safety Directors know very little about a very complex asphalt mix process. OSHA requires written energy control procedures for lockout and confined space. The Safety Program around the plant needs a be a collaborative effort with all involved and is best moderated by a qualified asphalt mix plant safety consultant.

 

Accidents happen in spite our best efforts to prevent them. We are human. Equipment does fail without warning. We may not eliminate all but we aim for zero defects.

 

So, let’s do a dry run and chat about how all of this should come together. The task at hand is to develop a written program that entails all the necessary procedures to protect maintenance personnel against the hazards of working in and around equipment.

 

The asphalt mix process uses equipment to perform one of the most complex industrial processes. The sheer volume of material processed and the vast amount of energy coupled with increasing customer demand to improved mix quality; all of this makes it a very difficult task to maintain safely. We never achieve perfection. We must not settle for anything short of excellence. And that is why we were all here.

 

Since the process is so complex and achieving the goal so important, our job is difficult. Nearly every piece of equipment at the plant is considered a permitted confined space. The drum mixer alone has nearly a dozen items that need to be locked out. Consider that 4 people may be working the project. That is nearly 50 locks hanging around the motor control cabinets on a dozen locking hasps.

Think about it. Fifty locks! That is unmanageable. The work will never get done without an extreme amount of frustration. Time to think outside the box while staying inside the OSHA Box. And that’s just what we did in one of our meetings.

In order, to keep a disconnect disconnected, it takes one lock on a locking mechanism.  If we put one lock on each of these 12 disconnects and make the keys to these locks inaccessible to anyone without the consent (consent.. permission to unlock by unlocking) of everyone, no disconnected can be reconnected. And if these keys are stored in a tool box equipped with a locking hasp, and if everyone places their lock on the tool box hasp; then we would have satisfied the intent of the OSHA Requirements, wouldn’t you figure?

 

I’m sure the result of our brain storming is not new and novel. But we used our heads for more than a hat rack. We were so intent on providing a solution for all concerned, all concerned came up with the answer until we came up with the answer. There is some power in persistence and collaboration. Don’t underestimate it.

 

Nearly 20 years ago, I began the development of a safety tool that has been in a ‘work in progress’ ever since. At the time, my plant operation training workshop was in it’s infancy. Safety was not much of an issue since I knew little. And little did I know, the industry did not know much more than I did. While facilitating a 3 day plant operation workshop in Cincinnati, I received a call from a lawyer. NAPA, the great leader in this industry, referred him to me. I was flattered by being referred. It was also an indicator that this may mean that nobody in the industry has had the time and tools to see personnel protection issues through. The lawyer was looking for a safety expert. “Sorry, I am not a safety expert”, I let him know.

Scenario, some poor soul put his head in between some pugmill doors and the doors closed on him. “Very unfortunate”, was all the comfort I could send him away with. I reported the incident to the class and asked them what they should lock before putting themselves in harm’s way. I was not impressed on what they knew and what some attitudes were. One fellow thought he could fix the problem by hiring someone with common sense. I asked him what needed to be locked out. After he exhausted all his ideas, the class added many more. It was at that time, I understood these ideas we came up with needed to be documented. Over the span of nearly a hundred workshops, we came up with a near complete list of ideas not only for lockout but making confined space and electrical maintenance an issue. . Just the other day, it was apparent it was important to enter some baghouses with more than just a dust mask. If your material contains silica, a respirator is a better solution. You see, our template is not perfect, but it is excellent. It is perfect in the way we allow you to add things we missed or things specific to your situation.

For every piece of equipment and every task on this equipment, this list of lockouts are married on one electronic, ‘fill in the blank’ form with permitted confined space and the proper electrical safety maintenance practices. This is major. This is huge. This is a break through. I often compliment my workshop participants with acknowledging their knowledge. They complement me by participating in a collaboration. I learn just as much from you as you from me. You are the message. I am the messenger.

By developing the proper template for the  tasks on every piece and cataloging them for future reference, you have met OSHA’s intent.

 

When people get hurt, we need to be prepared. Scenario, how do you get an incapacitated person out of the far end of your mixing drum or baghouse or on top of silo? What safety tools and manpower do you need? Have you ever drilled? At school there are fire drills. In the army, we drilled. Have you ever invited your fire department over and talked about these issues?

When conducting a safety written procedure meeting as a moderator,  we have included PPE safety tools for safely performing the work. What if someone gets hurt and incapacitated? What First Aid do we perform? What recuse operations are we prepared to perform while waiting for First Responders and rescue people? Have you talked to your Fire Department? Does your Fire Department have Rescuers? Not all Fire Departments do have rescuers and you may be summoning the wrong people.

Our role is not only to plan on accident prevention but perform the first aid when it does happen. Rescuing is part of first aid. Time is critical. We are there. We are the first responders. Be prepared to be there. What part of First Aid and Rescuing are you qualified to do?

 

Part of the facilitator’s job is in the safety program development was to keep us from complicating the process. It’s easy for that to happen. I facilitate these programs because I know the process much more than most Safety Directors. There were instances that the too many steps were taken when one step adequately performed the purpose. When we add too much work to the process, we find workers skipping the process altogether. When Safety Directors understand the asphalt mix process, they can work with the plant personnel for a solution that satisfies us all. They can help keep it simple.

We not only need to educate our Safety Directors, we need to educate our fire department. I encourage you to invite your fire department over to visit your plant so you can discuss your process and share ideas about rescue. It will be good practice for them to drill at your facilities. Give them scenarios and listen and then advise them on what they want to do. FYI: Many a baghouse has experienced further damage when a fire department was asked to respond to a baghouse fire.  Hint: Be patient. Keep the lids on it overnight. FYI: I don’t have to tell you not to put water on a grease fire. At least one fire department that I know about did just that at the oil tanks. Whose equipment is this anyhow? Take charge. Communicate before. Be proactive. Make life so much more uneventful. Are you in this for the long run? Cheap insurance. Why is it you have time to fix the problem afterwards but not before? Don’t forget to invite OSHA. FYI OSHA loves effective safety training.

 

For all of those interested in some direction on how to get your Safety Program continuously improving, you may want to check out what we are up to at Safety Director Web-Based Training .

Anyhow, please register and comment about our topic in our Forum.

I am sure you all have seen quite a bit in your times.

 

Clarence

 

 

The Missing Safety Link

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I have been working safety into my training programs for years and years. It is not till now that I am going to be able to take my work out for a test drive. Why is that? As much as we add lip service to our intentions, good intentions and a nickel will not buy us a cup of coffee. In short, the job has not been getting done by industry because industry is not seeing the payback.

How do you see payback when you do make the safety investments? We know how much the damage costs us when an incident happens. How much do we save when an incident does not happen? We don’t take the time to recognize that. We give production awards. We have concrete evidence.

I have the privilege working with a team this coming week about writing procedures for lock out and confined space procedures for every piece of equipment on the plant and the different situations this equipment is being maintained under. Situations like, “Is this inside or outside the equipment?”. Situations like, “Is this maintenance being performed under a planned shutdown or is it a mid production shutdown?”.

I do not believe we can eliminate all accidents. We must do what we can to practically eliminate what we can. We are humans. We don’t have control all the time.

The reason I am there is, there was a recent fatality. They seemed to be covered because they did receive some MSHA type training of sorts. Unfortunately,the training did not cover the details of what happens at an asphalt mix plant. It may have just been the details that got us or we have to chalk it off to we can’t win them all.

OSHA requires a written energy control procedure for lock out and confined space for each piece of equipment and for every situation to be documented for use when personnel need to use it. I am not sure there is a plant anywhere on the planet that can produce that.

That is what we are set out to do this week. To climb and conquer that mountain that know one has claimed to have conquered.

Our Web-Based training includes templates specific to most all the equipment at an HMA Facilities. We are going to use them to keep us organized. We are going to include the plant manager all the way to the maintenance welders. We will collaborate on all the different situations. We will identify where the lock out mechanisms are and discuss and document the procedures of what will be done when and where. We will discuss the issues of what OSHA wants us to do and how we can make that practical. We will discuss when we are going too far and what is logical.  e.g.There is no need to check the air with an air quality monitor before entering a cold feed bin, etc.

We are moving forward with a heavy heart. We lost a comrade. We must respect him and we want to let his legacy know that we are making these adjustments because it is the right thing to do and we miss him.

So what is the missing link? These people had the training and their plant operator had participated in our web training and had access to the procedure templates. If your management is not involved, the chain is broken. The management felt they were involved. Management knows the details about production and the bottom line. I am not picking on this one company. If the industry managements were keeping up, they would see to it that OSHA’s requirement for written procedures were followed through correctly.

I ran across a book a couple years back. I don’t normally read a book twice. I not only read it twice, I underlined the second time as I went along. There is a story in there that shows that putting your people first by training them in safety makes it easier to train them in their other duties. I think that story holds water. It’s a noble effort.  If you are having trouble training people on what is good for the company, switch it up. Train them on things that are for their own good. When you get that change in their life implemented, start implementing changes in their lives that make you money.

 

 

Variable Frequency Drives

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We shall start our blog discussing potential energy savings devices such as VFD drive plant retrofits. Right now, your entire industry is not taking advantage of the benefits and, in some instances, are installing an incomplete system. Come learn and come share.

Variable Frequency Drives have been around for a long time varying the speed of motors. VFDs can save you energy in some instances.

I want to focus on the quick paybacks that are available at the asphalt mix plant in those some instances.

If any of your plants are  running at half the speed most the time and you run about a 1,000 hours a year, you want to read further. At the moment, we are adding three 200 hp vfds and inverter duty motors to replace the two motors at the exhaust fan and the burner fan motor. These loads are centrifugal loads lend themselves to solve a problem the utility companies would like fixed. Most utility companies will chip in a healthy rebate. The utility company is chipping in $60,000 to this project. The customer chips in the balance and finds his Payback is about a year.

The savings projection the utility company is projecting was compared to our calculations and those of other engineers in like applications.

The variable speed fans replace the variable flow dampers and the actuators. The fans begin freewheeling as the damper is being modulated so less air is being pulled through. This lighter load makes the utility company to use more power than normal to get the work done. Consequently, the user gets charged for this.

The VFDs work well with the utility companies and the rest of the equipment on the power grid when properly filtered with reactors.

When you have an application like this, get your utility company and a consulting-contracting company that can work with your utility company to install what is beneficial to both the utility and the customer.

Since you are changing air flows in the combustion process, a consulting-contracting company that can design the electrical retrofit to your application and adjust the air to fuel ratio with a combustion analyzer is important.

So, it was a good idea on commercial power. How good of an idea are VFDs on portable generators? It appears to us, you are probably better off staying with damper control. Contacting your generator service department is a good start when you must add VFDs. They will probably suggest adding a Harmonic Inhibitor besides line and load filter reactors. Now you are loading up a portable plant with a bunch more heavy and big components.  I am not sure you want to go here.

Some people are adding VFDs to adjust the speed of their drum. In most instances, users are just varying the speed 5% to 10% to get the greatest heat recovery from the exhaust gases. This speed reduction is not much, normally does not require changing the motor to an inverter duty motor. The motor shaft does require grounding. A split ring, brush grounding kit must be added to each motor.

Clarence Richard