Closed-loop manufacturing

Use closed-loop manufacturing processes. Recycle auxiliary and process materials back into the manufacturing process. 

Tomani P and Seisto A. Separation methods for closed-loop manufacture of bleached kraft pulp—overview of an EU project. Desalination 1999 124 217-223. 

In Fig. 9.4 the delicate ecological balance (or lack of) is shown. Improving recycling, adopting closed-loop manufacturing, and extending the lifespan of products, can help balance growth with its environmental impact. 

Nickel sulfate also is made by the reaction of black nickel oxide and hot dilute sulfuric acid, or of dilute sulfuric acid and nickel carbonate. The reaction of nickel oxide and sulfuric acid has been studied and a reaction induction temperature of 49°C deterrnined (39). High purity nickel sulfate is made from the reaction of nickel carbonyl, sulfur dioxide, and oxygen in the gas phase at 100°C (40). Another method for the continuous manufacture of nickel sulfate is the gas-phase reaction of nickel carbonyl and nitric acid, recovering the soHd product in sulfuric acid, and continuously removing the soHd nickel sulfate from the acid mixture (41). In this last method, nickel carbonyl and sulfuric acid are fed into a closed-loop reactor. Nickel sulfate and carbon monoxide are produced the CO is thus recycled to form nickel carbonyl. 

This is an alternative to FOC and can provide a very fast response. The choice of a static drive, whether through a simple V7/control, field-oriented phasor control or direct torque control with open or closed-loop control and feedback schemes, would depend upon the size of the machine, the range of speed control (whether required to operate at very low speeds, 5% and below), the accuracy of speed control and the speed of correction (response time). The manufacturers of such drives will be the best guide for the most appropriate and economical drive for a particular application or process line. 

Process validation is the procedure that allows one to establish the critical operating parameters of a manufacturing process. Hence, the constraints imposed by the FDA as part of process control and validation of an SMB process. The total industrial SMB system, as described, is a continuous closed-loop chromatographic process, from the chromatographic to recycling unit and, with the use of numerical simulation software allows the pharmaceutical manufacturer rapidly to design and develop worst-case studies. 

Create a closed-loop system so that the industry recycles waste. Many copier and laser printer manufacturers have now done this, including the recovery and recycling of used toner cartridges as part of the overall service. 

Water is one of the most widely used raw materials in the manufacture of aqueous paint formulations. But as well as being used in production it can have a number of other uses, e.g. cooling and cleaning. Because of the cost of "new" water and disposal of contaminated water most manufactures have introduced closed loop or recycling systems. 

When the new product to be manufactured is the same as what it started as, for example a new bottle made from bottle scrap, the recycling is referred to as closed-loop. When the new application is different from the starting one, the process is referred to as open-loop recycling, as is the case when the polyethylene terephthalate bottle is used to produce polyester fiber for carpeting. 

The loss of expensive catalyst from the reactor system can be fatal for any process. Physical loss involves the removal of active catalyst from the closed loop of the process. This can include the plating out of metal or oxides on the internal surfaces of the manufacturing plant, failure to recover potentially active catalyst from purge streams and the decomposition of active catalyst by the process of product recovery. The first two can be alleviated to some extent by improvements in catalyst or process design, the last is an intrinsic problem for all manufacturing operations and is the subject of this book. 

Closed-loop recovery of valuable chemicals and water can be performed by wood treating sites or chemical manufacturers. 

Manufacturing process changes to simplify production technologies, reduce water and energy use, or introduce closed-loop recycling and... 

Most DCS were, and still are, being sold to refineries and chemical plants where the distances involved and the environment do not require microwave communication. Responding to the market demand, few manufacturers were interested in developing the technique. Such systems that were available were, quite naturally, configured around the concept of closed loop control at the PCM level. Consequently, none of them could compete with the SCADA system in terms of numbers of data acquisition points. Alternatively, none of the SCADA system manufacturers could provide a sufficiently intelligent remote unit to execute closed loop control. 

Brennan MB. New age paper and textiles Fungi, enzymes and closed-loop catalysis offer environmental, economic gains in manufacturing and recycling. CENEAR March, 1998 23 39-47. 

A newly developed manufacturing process may be implemented in an existing production line if it is not fully booked and an investment is saved. However, if there is no free capacity or if the new product requires new unit operations and processes a new plant needs to be built. The simpler manufacturing process the cheaper investment, but the investment part of today s closed loops due to environmental concerns, often constitute 30% of the total investment. The capacity of a new plant must be decided. A larger capacity is more expensive, although it is not a linear relationship. The investment cost is seen as a capital cost in the cost calculus of a new product, and it is dependent on the capacity utilisation. Therefore, the decision of a planned capacity will be taken in close cooperation with the company s marketing people. 

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