Inventory minimization

Often, the manager sets up a periodic inspection schedule to aid in inventory control. In this modified visual inspection, the inventory manager routinely inspects designated inventory levels, e.g., on a daily or weekly basis, to determine whether an order should be placed. This routine examination of inventory minimizes the potential for stockouts and can potentially improve inventory control. This is a fixed-time reorder system, in which the quantity ordered might vary but the date of ordering remains the same. This is ideal for small to medium businesses for whom a prime vendor is the main supply source and the true volume of activity can be determined easily. 

Inventory Minimization—The amounts of combustible gases and liquids that may contribute to an incident should be minimized for normal operations and during emergency conditions (limited vessel sizes, isolation provisions, blowdown and depressurization, etc.). The maximum allowable levels for operational and emergency periods should be identified as part of the design process and risk analysis. 

Reactor thermal power High Minimize time to use up cooling water inventory, minimize margins to critical heat flux, etc. 

Safety considerations might dictate that a particularly hazardous component be removed from the process as early as possible to minimize the inventory of that material. 

Distillation. There is a large inventory of boiling liquid, sometimes under pressure, in a distillation column, both in the base and held up in the column. If a sequence of columns is involved, then, as discussed in Chap. 5, the sequence can be chosen to minimize the inventory of hazardous material. If all materials are equally hazardous, then choosing the sequence that tends to minimize the flow rate of nonkey components also will tend to minimize the inventory. Use of the dividing-wall column shown in Fig. 5.17c will reduce considerably the inventory relative to two simple columns. Dividing-wall columns are inherently safer than conventional arrangements because they lower not only the inventory but also the number of items of equipment and hence lower the potential for leaks. 

The overall inventory. In the preceding chapter, the optimization of reactor conversion was considered. As the conversion increased, the size (and cost) of the reactor increased, but that of separation, recycle, and heat exchanger network systems decreased. The same also tends to occur with the inventory of material in these systems. The inventory in the reactor increases with increasing conversion, but the inventory in the other systems decreases. Thus, in some processes, it is possible to optimize for minimum overall inventory. In the same way as reactor conversion can be varied to minimize the overall inventory, the recycle inert concentration also can be varied. 

Choose the distillation sequence to minimize the inventory of hazardous material. 

Minimize inventory to the extent feasible. Expected benefits from minimum inventory may be offset by hazards resulting from more frequent and smaller shipments. The relative hazards should be reviewed (Englund, Design and Operate Plants for Inherent Safety—Part 1, Chem. Eng. Prog., vol. 87, no. 2, March 1991, pp. 85-91). 

Understanding the chemistry of the process also provides the greatest opportunity in applying the principles of inherent safety at the chemical synthesis stage. Process chemistry greatly determines the potential impact of the processing facility on people and the environment. It also determines such important safety variables as inventory, ancillary unit operations, by-product disposal, etc. Creative design and selection of process chemistry can result in the use of inherently safer chemicals, a reduction in the inventories of hazardous chemicals and/or a minimization of waste treatment requirements. 

Has the facility identified, evaluated and implemented controls to reduce risks associated with catastrophic chemical releases (for example, implemented any of the following measures minimization of on-site inventories, installation of early warning systems of chemical releases, proper containment or durable piping) involving toxic or volatile substances If yes, summarize the results. 

Operation includes nonual start-up, normal and emergency shutdown, and most activities performed by die production team. Whilst inlierently safe plant design limits inventories of hazardous substances, inherently safe operation ensures die number of individuals at risk are minimized. Access to die plant for non-essendal operational people such as maintenance engineers, post staff, administrators, quality control samplers, warehouse staff delivering raw material or plant items or collecting finished product, members of security, visitors etc., must be controlled. 

In fluidized-bed adsorbers, the combination of high gas rate and small adsorbent particle size results in suspension of the adsorbent, giving it many of the characteristics of a fluid. Fluidized bed adsorbers, therefore, lend themselves to truly continuous, countercurrent, multistage operation. Adsorbent inventory is minimized. 

M7 Improved Housekeeping, Training, Inventory Control (e.g., alter maintenance frequency institute leak detection program improved inventory control institute training program on waste minimization)... 

When designing a plant, every piece of process equipment should be specified as large enough to do its job, and no larger. We should minimize the size of all raw material and in-process intermediate storage tanks, and question the need for all in-process inventories, particularly of hazardous materials. Minimizing the size of equipment not only enhances inherent process safety, but it can often save money. 

Similarly, hazardous raw material storage should also be minimized, with greater attention being given to just in time supply. Inventory reduction lowers inventory costs, while increasing inherent safety. In determining appropriate raw material inventories, the entire raw material supply chain must be considered. Will the supplying plant have to increase inventories to provide just in time service, and will... 

Some processes have large heat transfer requirements. This may result in large inventories of material within the heat transfer equipment. If the material is thermally unstable it would be inherently safer to reduce the residence time in the heat exchanger. Options to minimize heat exchanger inventory include the use of different types of heat exchangers. Inventories in shell and tube heat exchangers can be reduced by the use of turbulators in the tubes to enhance heat transfer coefficients, and by placing the more hazardous material on the tube side. 

Heat transfer equipment has a great variation in heat transfer area per unit of material volume. Table 4.4 compares the surface compactness of a variety of heat exchanger types. Falling film evaporators and wiped film heat exchangers also reduce the inventory of material on the tube side. Process inventory can be minimized by using heat exchangers with the minimum volume of hazardous process fluid for the heat transfer area required. 

Minimize or eliminate in-process inventory of hazardous material, including inventory in the processing equipment as well as in tanks. Elimination of intermediate storage tanks will likely require improvements in the reliability of the upstream and downstream operations. 

Select a transportation mode to minimize risks to the extent practicable. Drums, ISO tanks, tank trucks, rail tank cars, barges, and pipelines offer tradeoffs in inventory, container integrity, size of potential incidents, distance from supplier or customer, and the frequency of incidents. 

Have all in-process inventories of hazardous materials in storage tanks been minimized ... 

Has all processing equipment handling hazardous materials been designed to minimize inventory ... 

Obviously, the risk of hazardous chemicals is reduced by a minimized inventory using just-in-time procurement. If further inventory reduction is not feasible, additional risk reduction may be achieved by dispersing the inventory to multiple site locations so a release in one location does not allcci other locations of inventory. 

Fire hazards are minimized by minimum inventories of chemicals. Control or miniini/e ignition sources, provide a confining area, reduce the temperature of the material as much iis possible, blanket the material to eliminate air contact. Have available fire protection equipment breathing apparatus, and protective clothing for the fire fighters. Use several hour fire walls to prevent the spread of fire to other process areas. 

The inventory of long-lived fission products is far less than an LWR because of the short exposure of the fuel to minimize Pu-240 production. But the health effects from an accident are comparable because it primarily results from short lived radionuclides. 

To guarantee shipment on time, you either need to maintain an adequate inventory of finished goods for shipment on demand or utilize only predictable processes and obtain sufficient advanced order information from your customer. When you examine some of the requirements in ISO/TS 16949, you may be tempted to question how you can continually improve performance, reduce costs, and minimize space, material travel, equipment downtime, process variation, etc. and meet 100% on-time shipments. You can t, unless you have a partnership with your customer in which there is mutual assistance to meet common objectives. Without sufficient lead time on orders you will be unlikely to meet the target. However, the standard does acknowledge that you may not always be successful. There will be matters outside your control and matters over which you need complete control. It is the latter that you can do something about and take corrective action should the target not be achieved. 

Fuel cannot be completely eliminated, though the inventory of combustible fuels can be kept to a minimum. Oil and gas will be present in any production facility, and either an oil spill or escaping gas can provide the fuel needed. Escaping gas can result from rupture, opening a closed system, or gas that is normally vented. The amount of fuel present can be minimized by preventing oil spills and gas leaks. 

Intermodal service must improve for corporations that adopted just-in-time inventory in the 1980s and 1990s. Many companies feel that the benefits of keeping minimal stock are worth the premium price paid for faster door-to-door deliveiy by truck, which is a major reason why truck freight revenues remain at more than 80 percent of the country s total freight revenues. 

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