Purchasing feedstock

Caustic that is added downstream of the crude oil desalter. Caustic is injected downstream of the desalter to control overhead corrosion. Natural chloride salts in crude decompose to HCl at typical unit temperatures. Caustic reacts with these salts to form sodium chloride. Sodium chloride is thermally stable at the temperature found in the crude and vacuum unit heaters. This results in sodium chloride being present in either atmospheric or vacuum resids. Most refiners discontinue caustic injection when they process residue to the FCC unit. It can still be present in purchased feedstocks, however. 

Processing residue or purchased feedstocks. Sometimes, the option of processing supplemental feed or other components, such as atmospheric residue, vacuum residue, and lube oil extract, is a means of increasing the yields of higher-value products and reducing the costs of raw material by purchasing less expensive feedstocks. 

Many companies resist this logic, arguing that they have to remain vertically integrated because they have no other way of purchasing feedstocks or of selling intermediate products. In reality, though, growing merchant markets exist for most products. Even with such a major raw material as ethylene, numerous companies... 

A comparison of overall treatment costs (purchase and refining) for several crude oils enables the refiner to establish his feedstock requirements and to satisfy the market needs under the most economical conditions. 

Key contents of a purchase profile report for a specific chemical are identity, location, and capacity of primary vendors expected additions or deletions of capacity and their timing captive use/merchant supply status of each vendor pricing history pricing induences (feedstock, energy, etc) demand by use and anticipated growth and demand in the purchaser company up to five or ten years ahead. 

The advent of a large international trade in methanol as a chemical feedstock has prompted additional purchase specifications, depending on the end user. Chlorides, which would be potential contaminants from seawater during ocean transport, are common downstream catalyst poisons likely to be excluded. Limitations on iron and sulfur can similarly be expected. Some users are sensitive to specific by-products for a variety of reasons. Eor example, alkaline compounds neutralize MTBE catalysts, and ethanol causes objectionable propionic acid formation in the carbonylation of methanol to acetic acid. Very high purity methanol is available from reagent vendors for small-scale electronic and pharmaceutical appHcations. 

By virtue of the nature of the paraffinic feedstocks readily available, commercial chlorinated paraffins are mixtures rather than single substances. The degree of chlorination is a matter of judgment by the manufacturers on the basis of their perception of market requirements as a result, chlorine contents may vary from one manufacturer to another. However, customers purchasing requirements often demand equivalent products from different suppHers and hence similar products are widely available. 

Feedstocks. A separate breakdown between fuels and feedstocks (qv) for the chemical industry (2) shows that the quantity of hydrocarbons (qv) used direcdy for feedstock is about as great as that used for fuel (see Fuels, synthetic Gasoline and other motor fuels). Much of this feedstock is oxidized accompanied by the release of heat, and in many processes, by-product energy from feedstock oxidation dominates purchased fuel and electricity. A classic example is the manufacture of nitric acid (qv) [7697-37-2] HNO. Ammonia (qv) [7664-41-7] burned in air on a catalyst at a pressure... 

Converting Heat to Work. There has been a historic bias in the chemical industry to think of energy use in terms of fuel and steam (qv) systems. A more fundamental approach is to minimise the input of work potential embedded in the fuel and feedstock, as well as work purchased direcdy as electricity. Steam is really just a medium of exchange, like money in an economy. 

More than 60 percent of natural gas physically consumed in the course of a year is nevertheless attributable to purchases at lower, interruptible prices by industrial boilcr-fucl users and electrical generators that are capable of substituting natural gas in off-peak months, when gas is available at prices competitive with those of black fuels (coal and heavy fuel oil). In addition to these relatively low-value, pricc-scnsitivc industrial gas uses is a wide range of intermediate-value demand categories for natural gas, such as in process and feedstock use. 

Most refineries produce sufficient gas oil to meet the cat crackers demand. However, in those refineries in which the gas oil produced does not meet the cat cracker capacity, it may be economical to supplement feed by purchasing FCC feedstocks or blending some residue. The refinery-produced gas oil and any supplemental FCC feedstocks are generally combined and sent to a surge drum, which provides a steady flow of feed to the charge pumps. This drum can also separate any water or vapor that may be in the feedstocks. 

Feed characterization relates product yields and qualities to feed quality. Knowing the effects of a feedstock on unit yields, a refiner can purchase the feedstock that maximizes profitability. It is not uncommon for refiners to purchase raw crude oils or FCC feedstocks without knowing their impact on unit operations. This lack of knowledge can be expensive. 

The teed to the cat cracker in a typical refinery is a blend of gas oils from such operating units as the crude, vacuum, solvent deasphalting, and coker. Some refiners purchase outside FCC feedstocks to keep the FCC feed rate maximized. Other refiners process atmospheric or vacuum residue in their cat crackers. In recent years, the trend has been toward heavier gas oils and residue. Residue is most commonly defined as the fraction of feed that boils above 1,050°F (565 C). Each FCC feed stream has different distillation characteristics. 

Purchased FCC feedstock can be exposed to salt water as ballast. 

Individual a-olefin feedstocks were purchased from Aldrich Chemical Company. The Ci0-Ci4 paraffin dehydrogenate was obtained from a commercial LAB plant and contained 8.5% Ci0-Ci4 olefins, primarily a mixture of internal olefins. 

Labor time charge entry and reporting Customer account charging and/or billing Inventoried product data for order entry processing QC test data for feedstock purchasing and vendor qualification... 

It determines acceptance or rejection of raw materials and feedstocks and/or assesses their market value for the purchasing department. It... 

Another development is that China National Technical Import Corporation (CNTIC), a unit under Ministry of Foreign Trade, is losing importance to CNCCC, which is under MCI. CNCC is responsible for purchasing and constructing chemical and petrochemical plants with MCI controlling the bulk of funds and the allocation of crude oil, which is used as feedstock. 

While higher-activity catalysts are valuable, future improvements will likely focus more on selectivity improvements. Higher activity means less catalyst needs to be purchased, which is an infrequent, rather than continuous, investment. Selectivity improvements, in contrast, represent a reduction in the feed needed for a given amount of product, so that is a reduction in the feed needed for every day of operation. Since feedstock is often the largest contribution to product cost, selectivity improvements can be quite valuable. Unlike activity improvements, which may shrink the size of the isomerization reactor, better selectivity can reduce the size of all units in the system due to reduced feed and reduced recycle. In an existing unit, the effective throughput would increase. 

Biofuels such as biodiesel and bioethanol are, for now, the main alternatives to fossil fuels for the most polluting activities related to transportation. Presently, feedstocks for biofuels production are all of natural origin and as such are subject to uncontrolled seasonal variations. For economic reasons the purchase of these feedstocks from different parts of the world follows the dynamics of commodities markets. ... 

Since the QA/QC laboratory is concerned with the quality of the firm s products, it can influence product costs and revenues (the cash flow associated with the products). It determines acceptance or rejection of raw materials and feedstocks and assesses their market value for the purchasing department. It frequently initiates the processing of claims against vendors providing raw materials which are below grade specification but are nevertheless used. The lab also may be responsible for process monitoring to determine process parameters which minimize the production of scrap or off-grade product. 

Should MTBE be banned, what would be the logical replacement(s) There are several options available. Several refiners opted to build MTBE capacity and avoid purchasing the ether on the open market. MTBE units were an option to use the facility s isobutylenes. Several licensed processes can be used to convert existing MTBE units. Kvaerner and Lyondell Chemical Co. offer technologies to convert an MTBE unit to produce iso-octane, as shown in Fig. 18.27.12 Snamprogetti SpA and CDTECH also have an iso-octene/iso-octane process. These processes can use various feedstocks such as pure iso-butane, steam-cracked C4 raffinate, 50/50 iso-butane/iso-butene feeds, and FCC butane-butane streams. The process selectively dimerizes C4 olefins to iso-octene and then hydrogenates the iso-octene (di-iso-butene) into iso-octane. The processes were developed to provide an alternative to MTBE. The dimerization reactor uses a catalyst similar to that for MTBE processes thus, the MTBE reactor can easily be converted to... 

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