Go Lean

It's time for the chemical industry to embrace this production strategy.

By Adam Russell, Eastman Chemical Co.

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We're not conditioned to talk to customers' customers or suppliers' suppliers. However, processors in the value stream working together in their mutual interest increase the probability of success for everyone. The automotive industry has many examples of this.

The versatility of our chemical technologies and products leads to very few "straight chains" between our companies and end users. So, it can be tough to identify in a meaningful way with the needs and activities of other processors along the value stream and, finally, the end consumer. But it's essential. We must go beyond merely conforming to product specifications (although that's necessary) and understand fitness for use.

Changing an organization's DNA is very difficult. You must get people to think broadly and seriously about value-stream needs and activities inside and outside your company's fences. This is the third step to becoming Lean.

Mapping is fundamental to understanding the needs and activities throughout the value stream. However, the insights gained won't generate results without a proper Lean framework. At this point, it's important to consider two pillars of a Lean system: flow and pull.

Let's begin with flow, a concept well known to chemical engineers. However, Lean flow is more than a system of unit operations. It requires thinking of the "work" performed by chemical processors through a different lens. Consider the following:

A manufacturer purchases and transports raw materials to its plant. It stores the materials (e.g., in warehouses, tanks or moving equipment) until they are ready for processing. Then the materials go (e.g., through piping or machines) to batch or continuous processing systems. Finally, products are sent to storage equipment or warehouses until they are ready for transport from the site to another facility.

This sequence applies to all manufacturing — details of specific value-stream activities differ depending upon industry. Ideally, the value flows smoothly toward the customer (order to delivery) without interruption in both physical and information processes. However, all manufacturing suffers flow interruptions due to various design, operational and maintenance factors.

Interrupted flow, regardless of the underlying cause, creates more dead time in the system and limits the potential (maximum) throughput of the end-to-end value stream. The dead time associated with raw materials and products usually dominates the total lead time of the end-to-end chemical value stream.

Dead time leads to more inventory. Typically, a chemical processor performs value-adding work only during a very small percent of the total lead time. Other industries commonly report 5–10% of the total lead time is value-adding. You might assume chemical processors do better because of their continuous unit operations. This often is a wrong assumption. Here's why:

Chemical plants are designed to run optimally (i.e., provide highest yield, etc.) at target production rates. Starting up, shutting down and slowing processes can often be costly. So, sites tend to run long campaigns and allow inventory levels to cycle up and down around planned (or unplanned) maintenance activities or product changeovers. Another Chemical Processing article [1] pointed out the benefits of shortening changeover activities and, in general, making them less painful. The advantages of this are clear: lower inventory and more capacity.

There's a lesson in this for chemical plant designers: consider right from the outset of work on any new plant or expansion the need to provide an inherent ability to manage chemical processes for optimum inventory control, proactive maintenance and frequent product changeovers. In other words, design in the ability to pull product through the value stream without overproduction and allow for cost-effective operation over a wide range of output rates. Much of the chemical industry today suffers a strategic disadvantage because it doesn't have these capabilities in a broad way.

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