Customer | Hydrite Chemical Company
Project | New operator workstations for the process control system
Location | Cottage Grove, Wisconsin, USA
Completion | 2010
Hydrite Chemical Company produces and distributes products for the food and beverage industry, fluoride for water treatment plants, and numerous cleaning and sanitation chemicals for customers in a wide range of industries. Hydrite works with many partners to offer their customers high-quality products.
Hydrite processes many materials in hazardous areas and the processes are therefore subject to stringent safety requirements. In the company's plant in Cottage Grove, Wisconsin, USA, most of the plant is designated as Class I, Division 1. Other areas in the plant are classified as Class I, Division 2. All of the devices in the plant must have the appropriate approval. Hydrite's plants are ISO 9001:2000 certified, which ensures that the products are of a consistently high quality, and all processes are reproducible.
Chemicals are manufactured in batches. The process is controlled part automatically and part manually, as needed. There are typically several raw materials tanks with contents coming from drums, sacks, or bulk containers. The correct proportions must be carefully controlled according to the recipe. The time from the start of the batch process until its completion may last a few hours to several days. Once the process is started, any interruption or failure can spoil the batch. In the production of the product itself, process control must take into account emissions as well as byproducts and waste products.
Paul Anderson is an electrical control and instrumentation engineer at Hydrite Chemical Company, and he had the task of modernizing the plant in Wisconsin. This modernization process involved acquiring new operator workstations. A comprehensive set of specifications was drawn up, the key requirement being an open, nonproprietary system. A future-proof choice would enable future changes to the system topology to be implemented easily. The operator workstations needed to:
Paul Anderson sought a long-term relationship in order to maintain and service his systems on an ongoing basis and to upgrade them in the future.
Paul Anderson chose a control system with intrinsically safe remote I/O modules. These offered Hydrite two distinct advantages:
The segmented system provided reliable system availability. For example, remote I/O modules can be changed without interrupting ongoing operation.
Access to batch and process information in the plant itself saves time and can prevent system failures. To support the employees effectively, the monitors had to be situated in the manual addition area and be designed for the environmental conditions there. They had to be equipped with a hardened touchscreen suitable for constant use by plant personnel.
To meet these requirements, Hydrite chose to use industrial monitors from Pepperl+Fuchs. These monitors have Class I, Division 2 approval and are designed for continuous use over an extended period of time under heavy-duty conditions.
Paul Anderson chose the operator workstations from Pepperl+Fuchs because they were the only ones that met all of his requirements. The operator workstations are particularly reliable, even under difficult environmental conditions, such as significant temperature fluctuations or vibrations, and a corrosive atmosphere. They also have a long mean time between failures (MTBF). Paul Anderson emphasized that the MTBF for these monitors is 500,000 hours—twice that currently offered by other manufacturers of industrial monitors.
The industrial monitors are installed in a NEMA 4X Division 2 stainless steel housing (SUS 316), with a pedestal or wall mount. The housing dimensions are smaller than those of the previous explosion-proof units (less space required, lower costs). With the hardened resistive touchscreens and the industrialized electronics, the monitors in the hazardous area of the plant are able to display the same high-quality picture as the monitors in the control room without requiring any reprogramming. This means that the same functionality is available in the plant as in the control room. Plant personnel no longer have to make several trips each day from the plant to the control room. Paul Anderson says: "The sharpness and brightness of the display are outstanding with the Pepperl+Fuchs solution." It is easier for the operators to make changes and adjustments. By placing powerful and reliable operator workstations in the field, on-site process information is available. This enables quicker responses, where required, while avoiding unnecessary and costly downtime, and lowering maintenance costs. There are also less obvious benefits, such as lower power consumption and less heat dissipation.