Carefully evaluate your current situation, determine your goals, understand your budget and know your options. By proceeding cautiously and making sure you have the right information, you can ensure that the changes you make to your kiln have a positive effect on your productivity and your bottom line.
Excessive Operating Costs. Excess fuel consumption is a common problem in the ceramic industry. Causes can include excessive heat loss or cold air leakage, too much dead load in the kiln furniture or kiln insulation, insufficient kiln insulation, inefficient use of heat input to the process, insufficient control of gas use and/or temperature, obsolete hardware, a cycle time that is too long and/or an incorrect setting density. Give your process an energy audit to find out how much energy is being consumed, where it is being consumed and where improvements can be made to reduce energy consumption (see Figure 1). Working closely with a consultant or kiln builder can help you ensure that the audit is thorough and complete.
Another important factor in evaluating your current situation is the cost of labor. In some cases, automation might be needed to reduce the risk of worker injury in loading and/or unloading operations. In other cases, the plant layout may need to be changed to ensure the most efficient use of the space or of workers’ time.
Find out how your plant’s operating costs compare with other plants in the industry, but make sure you’re comparing similar situations. Know the source of any data you obtain, and make sure the data is accurate.
Poor Production Quality. If you are experiencing excessive quality spreads or low yields of premium-quality products, it may be time to reevaluate your firing operation. However, be certain that you know the source of the problem before you invest in a solution. Problems that emerge after firing can sometimes be caused in the drying or forming process or by the body formulation. Map your current product quality, including characteristics such as shrinkage, absorption, strength, color and any other important criteria, so that you can determine whether changes in the firing process can improve these characteristics.
Insufficient Production Quantity. If your kiln requires excessive cycle time to produce the amount of product you need, it could be kiln-related; however, it might also be product-related. For example, a 20% slower cycle time might be required to fire 10% of your total product line. Rather than investing in an upgrade or new equipment, you might be able to gain greater efficiencies by simply making that product in a different location or by not making it at all. Other causes of reduced production can include limited production scheduling or a bottleneck elsewhere in the manufacturing process, such as grinding. Make sure you know the source of the problem before investing in a solution.
Safety Issues. Evaluate the mechanical, electrical and operational safety of your current equipment. Make sure that the appropriate guards are in place, that the mechanical interlocks are functional, that sufficient platforms provide access to maintain the equipment, and that barriers separate personnel from mechanical activity.
Find out whether the equipment follows the appropriate electrical and combustion safety codes. Older equipment should follow the codes that were in place when the equipment was installed, while newer equipment should follow more recent codes. If you’re considering an upgrade, be aware that making major changes to an older system might require the equipment to be modified to meet the current codes.
Determine whether the equipment is operating above defined electrical limits, and make sure accurate electrical schematics are available to permit maintenance efforts. You should also examine the existing combustion safety systems—including flame safety systems, temperature limiters, pressure and flow interlocks, solenoid valves, vents, leak detection systems and alarms—to make sure they are operational.
Make sure that your kiln operators are working in safe conditions, that they have safe access to all kiln controls and functions, and that they are properly trained in safe operating techniques. Determine whether automation might be required in loading, unloading or other kiln-related operations to reduce labor safety concerns.
If your evaluation reveals that the equipment has reached the end of a reasonable “safe” operating life, changes will most likely be needed to ensure the continued safety of your employees.
Environmental Issues. Federal and state environmental agencies will probably tighten permissible effluent levels in the future. Determine whether your existing kiln can or should be adapted to meet more stringent emissions regulations. If your equipment has been “grandfathered” to operate under the current regulations, be aware that upgrading the system to improve its performance may require you to add new pollution abatement equipment.
Asbestos is another common environmental problem. Find out whether you have asbestos in your kiln, and understand your options. If you know your kiln contains asbestos but you can’t afford to remove it, an upgrade isn’t feasible, since disturbing the asbestos can create serious health risks. Instead, you’ll need to either continue operating your kiln in its current condition or build a new kiln in another location. If you decide to leave the asbestos in place, make sure you implement the necessary procedures to prevent human exposure to it. If you decide to have the asbestos removed so you can retrofit or replace your kiln, you’ll need to hire specialists to ensure safe removal.
Obsolete Process Control/Data Acquisition/Production Technology. If you have an insufficient amount of control over your process, insufficient data about your process or obsolete production technology, you might want to consider upgrading your kiln to correct the situation. However, the problem might also be due to incorrectly or inefficiently using existing data and technology. Make sure your employees know how to use the existing equipment to its maximum potential. If you decide to purchase new equipment, make sure your employees receive proper training so your investment is not wasted.
Retrofitting or replacing your kiln might save you money, make you more competitive and provide you with greater peace of mind. It can help you reduce fuel usage and product losses, improve product quality and maintain better control of your firing process. However, make sure you have all of the data in hand—and that the data is accurate—before you make any changes to your firing process.
No one else can make the decision for you. Whether you retrofit or replace your kiln, or any other piece of equipment in your plant, depends entirely on the cost versus the benefit to your facility.