Alkylation processes costs

Acid modifiers have been used to a limited extent to reduce acid consumption in the H2SO4 alkylation process (27). Increased catalyst costs will encourage the further development and appHcation of such acid modification techniques in the future. In addition, the development of new technology, such as two-step alkylation, may be accelerated based on the incentive to reduce catalyst consumption and increase product octane (28). 

HP Alkylation Process. The most widely used technology today is based on the HE catalyst system. AH industrial units built in the free world since 1970 employ this process (78). During the mid-1960s, commercial processes were developed to selectively dehydrogenate linear paraffins to linear internal olefins (79—81). Although these linear internal olefins are of lower purity than are a olefins, they are more cost-effective because they cost less to produce. Furthermore, with improvement over the years in dehydrogenation catalysts and processes, such as selective hydrogenation of diolefins to monoolefins (82,83), the quaUty of linear internal olefins has improved. 

Although inclusion in motor gasolines is the most obvious alternative use for alkylate, this process would have to be economically competitive with processes such as polymerization, which also convert gaseous hydrocarbons to gasoline. Since the chief obstacle to the use of alkylate in motor gasolines is its high processing cost, it would appear that future research should be directed toward improvements in the process which will reduce these costs. 

One of the major items contributing to the high processing cost is the cost of the catalyst consumed. This is particularly true for propylene alkylation, where the catalyst cost is about 2.5 to 3.0 cents per gallon of alkylate produced. Several courses that research might follow in order to reduce catalyst consumption would be the development of a more efficient reactor, a more efficient catalyst, or an additive which would retard catalyst degeneration. 

Another factor which contributes most to the high cost of the alkylation process is the necessity of having a large excess of isobutane in the reaction zone. This requirement results in increased capital costs for over-sized reactors, settlers, fractionators, and accessories, as well as in increased operating costs of this equipment. Process developments which would allow satisfactory operations at considerably lower isobutane-to-olefin ratios would help reduce these costs. Such developments might again involve improvements in reactors or in catalysts. 

Over the years H2S04 alkylation capacity has declined relative to HF alkylation.303,304 Reasons for this trend are a significantly lower acid consumption, overall lower operation costs, and less expensive regeneration plant cost and operating expenses of the HF alkylation process. Because of the mentioned environmental hazard associated with anhydrous HF and the need for further improvement of alkylate quality, improved technologies for sulfuric acid alkylation emerged, although it is improbable that there will be a major turnback to sulfuric acid alkylation. 

Alkylation processes with strong acid catalysts are fraught with many difficulties. Problems Involved are the handling of highly corrosive and costly acids and the necessity of pretreatment of alkylates aimed at removal of traces of acids, harmful sulphate esters, and some others. 

Figure 2. Savings in alkylation acid processing costs resulting from operation of ester concentration system...

Considerable reduction in acid requirements and alkylation production cost are obtained by ester concentration, as shown by Figure 2. The operation of the earlier plant demonstrated the process operability of the system, but disclosed mechanical and operational limitations of equipment available that made the process uneconomical at that time. Today energy costs have changed and sulfuric acid is no longer worth 20/ton. This process, installed in an alkylation unit with the equipment available today, can be an Integral part of the alkylation system to substantially reduce alkylate production costs. 

The cost of the acids, the relative hazards of each, the actual alkylate yield and quality all must be considered when selecting the alkylation process to use. The installed cost of the plant and operating costs also must be considered. Oost savings can be realized if octane quality is lowered. 

Alkylation processes using HF require in general larger columns, which also have significantly higher operating costs. First, they operate in general with... 

Linear alkylbenzene enjoys worldwide acceptance as a cost-effective and environmentally friendly intermediate used in the production of household and industrial cleaning formulations. Both HF acid and solid-bed alkylation processes are cost-competitive routes for the manufacture of LAB. Solid-bed alkylation process produces fewer environmentally hazardous by-products and employs a less complex facility when compared to HF route. With the breakthrough development of commercially demonstrated and expected future refinement, the solid-bed alkylation technology is expected to meet the continued growth in LAB. 

Several operating variables in both liquid catalyst alkylation processes impact product yields and quality as well as overall costs ... 

CDAlkyPlus An improved alkylation method that allows operators to alkylate any concentration of isobutylene as much as 100% of the total olefin fraction. The process is said to provide considerable savings in operating and capital costs. It utilizes two commonly used refinery processes that allow inexpensive alkylation of isobutylene as the only olefin source. A simple isobutylene pretreatment process is used upstream of the low-temperature sulfuric acid alkylation process. Developed by CDTECH. 

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