Claus costs

Contractors should also have indicated their completion times for retrofits for minimiun impact on shutdown times. Consider penalty clauses, cost plus clauses, and other relevant expense items. 

Another variation of the Selectox process can be used with the Beavon process in tail gas treating. The hydrogenated Claus tail gas stream is sent to a Selectox reactor. Overall recoveries of up to 98.5% are possible. Use of Beavon/Selectox, however, typically costs more than use of Superclaus. 

If the toller improves the yield, or produces more product than expected from the quantity of raw materials used, it may be appropriate to share in the cost savings on some basis. Performance clauses and bonuses for production can be part of the formal agreement negotiated between the parties. 

Availability and reliability have a very major impact on the plant economy. Reliability is essential in that when the power is needed it must be there. When the power is not available it must be generated or purchased, and can be very costly in the operation of a plant. Planned outages are scheduled for non-peak periods. Peak periods is when the majority of the income is generated as usually there are various tiers of pricing depending on the demand. Many power purchase agreements have clauses, which contain capacity payments, thus making plant availability critical in the economics of the plant. 

The first two statements in clause 4.1.1.4 create an ambiguity when read together. The first calls for improvements in quality, service, cost, and technology (but not productivity) to be provided for in the quality policy but not implemented and the second calls for improvement in quality and productivity to be identified and implemented with no mention of cost, service, or technology. 

There is also a supplementary requirement in clause 4.1.3.2 for the management review to include the monitoring of strategic quality objectives and the regular reporting and evaluation of the cost of poor quality. 

The corrective action requirements fail to stipulate when corrective action should be taken except to say that they shall be to a degree appropriate to the risks encountered. There is no compulsion for the supplier to correct nonconformities before repeat production or shipment of subsequent product. However, immediate correction is not always practical. You should base the timing of your corrective action on the severity of the nonconformities. All nonconformities are costly to the business, but correction also adds to the cost and should be matched to the benefits it will accrue (see later under Risks). Any action taken to eliminate a nonconformity before the customer receives the product or service could be considered a preventive action. By this definition, final inspection is a preventive action because it should prevent the supply of nonconforming product to the customer. However, an error becomes a nonconformity when detected at any acceptance stage in the process, as indicated in clause 4.12 of the standard. Therefore an action taken to eliminate a potential nonconformity prior to an acceptance stage is a preventive action. This rules out any inspection stages as being preventive action measures - they are detection measures only. 

The SCOTT process uses an amine to remove the HjS. The acid gas off the amine still is recycled back to the Claus plant. Other types oi processes oxidize the sulfur compounds to SO2 and then convert ihc SO to a secondary product such as ammonium thiosulfate, a fertilizer. These plants can remove more than 99.5% of the sulfur in the inlet stream to the Claus plant and may eliminate the need for incineration. Costs of achieving this removal are high. 

The contract is usually for a period ranging from 3 to 9 years, but in this case the amount payable to the contractor is the same or similar to the costs prior to contractor take-over. A further clause is added such that a proportion of the savings made by the contractor are returned to the client (perhaps 2-10 per cent of the previous annual costs). It may also be possible for any further large saving to be shared in agreed proportions between the two parties involved. 

Doing it more cheaply (outsourcing contracts can face cost escalation, or painful and expensive break clauses when the real scope of work is discovered)... 

If, besides the quality-related measure, z, one also wishes to include operating costs, in the analysis, because quality loss functions express quality costs on a monetary basis, commensurate with operating costs, the final global performance metric, y, which reflects total manufacturing cost, is simply the sum of both quality and operating costs (Clausing, 1993),... 

In the event of early termination if pa)nnent (whether for salaries or otherwise) has been made by the Sponsor to the NHS Trust in advance for work not completed such monies shall be applied to termination related costs and in the case of termination pursuant to clause 12.4 above towards the compensatory pa)unent payable pursuant to clause 12.6 and the remainder of the monies shall be returned forthwith to the Sponsor. 

Since the Selectox process is capable of well over 90 percent sulfur recovery, the authors recommend a careful cost-benefit study to see if Claus tail gas processing should be required with such plants. It might well be found that—say—95 percent capture of sulfur in the coal conversion plant is acceptable. 

Scaling Up from Laboratory Data Laboratory experimental techniques offer an efficient and cost-effective route to develop commercial absorption designs. For example, Ouwerkerk (Hydrocarbon Process., April 1978, 89-94) revealed that both laboratory and small-scale pilot plant data were employed as the basis for the design of an 8.5-m (28-ft) diameter commercial Shell Claus off-gas treating (SCOT) tray-type absorber. Ouwerkerk claimed that the cost of developing comprehensive design procedures can be minimized, especially in the development of a new process, by the use of these modern techniques. 

There is also no grandfather clause for studies completed or in progress or in the extant literature. Unfortunately, no one considered the costs of repeating everything that did not anticipate their good ideas. An additional unforeseen consequence is that repeated studies will have to compete directly with new initiatives for program space and resources. Delays will result in economic losses to producers and manufacturers, and in increased costs to consumers. Apparently, none of these points are considered important enough to make it into a cost/benefit statement. 

Catalysts help customers comply cost-effectively with clean-air regulations. Hydrocarbons, carbon monoxide, and nitrogen oxides can be removed using supported precious metal catalysts. Organic sulfur compounds are converted to H2S using nickel/molybdenum or cobalt/molyb-denum on alumina catalysts. Sulfur can be recovered in a Claus process unit. The Claus catalytic converter is the heart of a sulfur recovery plant. 

Shell also offers for license a -selective version of the Shell ADIP Process. The ADIP process, which has a flow scheme very similar to Sulfinol, can be used to treat the Sulfinol acid gas to raise the H2S concentration by selectively rejecting the CO2. Some integration of the SCOT process with the ADIP process is often possible thus, reducing overall equipment and operating costs. Costs for the Claus plant are substantially reduced when "selective" ADIP is applied. Two selective ADIP plants are scheduled to come on stream in the first half of 1979. 

A detailed discussion of optimization of sulfur recovery facilities would comprise another paper in itself, and therefore, is outside the scope of this paper. Costs of hydrogen production, which are presented in Figure 5 and Tables III and IV do not include sulfur recovery (Claus, etc.) costs or sulfur... 

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