Chemical industry

Chemical Industry

The chemical industry is comprised of numerous sectors. A major search engine for the industry, for example, breaks the industry up into no fewer than 47 different categories. What follows are a few of the major sectors within the industry.

Glass manufacturing

Glass manufacturing is a process that is largely dependent on raw material quality control, as in process controls are limited by the fact that the process for manufacturing glass is high temperature, and does not lend itself to any sort of sampling process. That being said, temperature is actually a key control measure, and multivariate process control methods have been developed to maximize finished product quality.

The nature of the raw materials, as well as the particulars of the physical manufacturing vary greatly based on the nature of the glass. However, many of the tests, especially on the raw materials are fairly similar - especially fineness of the powders.

Once the glass itself has been manufactured to appropriate grade for the intended application, the actual glass products are produced. There are several processes used, one being glass blowing (generally machine based, although some specialty glass pieces are still blown by people), the float and rolled methods for producing sheets of glass, and glass fibre processes. Most finished product testing involves physical measurement and observation.

For one particular type of glass, additional tests are required beyond straight physical measurements. In the case of insulated glass, besides physical inspection, measurement of the inert gas content (frequently argon) of representative samples is important. Control of this process is sufficiently important that a standards organization has developed to establish both processes and a certification program for insulated glass manufacturers.

Environmental monitoring and glass manufacturing

Significant attention has been paid to the environmental impact of glass manufacturing. Traditionally, arsenic and particulate matter were monitored in airborne pollutants, with nitrogen oxides and sulfur oxides being added in as significant contributors to smog, and thus lessening air quality.

Petrochemicals

Petrochemicals refer to products made from both petroleum, or crude oil, and natural gas. Crude oil and natural gas are used to produce primary petrochemicals, such as ethylene, methanol, benzene, and the like. These chemicals are then used to produce a variety of intermediate and derivatives which ultimately are used to produce an amazing array of materials of great importance to the modern industrial world, such as plastics, tires, solvents, and the like.

The process for producing most petrochemicals is cracking - the process of converting longer chain hydrocarbons into smaller hydrocarbons. A variety of cracking techniques exist. Thermal cracking, as it’s name implies, uses heat (and generally high pressure) to effect the chemical reactions. Other processes involve catalysts (called fluid cracking) or hydrogen.

Quality control for petrochemical derivatives

The source of primary petrochemicals governs the complexity of the process used to generate them. For instance, the production of Ethylene in Asia and Europe, is done by cracking naptha, gasoil, and condensates, while in North America and the Middle East the raw material is ethane and propane, which makes for a simpler process (with a lower production cost), but also with a smaller variety of products.

Environmental monitoring of petrochemical production processes

The entire chain of petrochemical manufacturing necessitates significant efforts to protect the environment through monitoring. This includes monitoring systems that watch for oil leakage into sea water, to contamination of the soil for land based drilling. Refineries, cracking facilities and subsequent manufacturing have the potential to introduce large quantities of very toxic substances into air, water, and soil, and thus monitoring and control systems are critical for all of these steps.

Inorganic chemicals (sulfur, halogens, photographic chemicals, electronics chemicals)

Inorganic chemicals are manufactured from salts, metal compounds, minerals as well as from the atmosphere (inorganic manufacturing encompasses production of industrial gases). These chemicals are, in turn, used in a variety of end products. Many inorganic chemical products are catalysts that are used in other manufacturing processes, and thus will never be seen in a finished product.

Inorganic chemicals can be used in some of the most sensitive manufacturing applications, for instance the production of silicon wafers and other electronic components. In these applications, extremely high purity is the main focus. Purity of the raw material, low particulate air, and tightly controlled manufacturing processes are fundamental.

Silicon single crystal

Integrated circuits require extremely pure silicon to produce (>99.9999% pure), and are produced in facilities that are able to maintain a class 1 or better air rating (1 .5 micron particle per cubic meter of air). This air rating is 10 times higher than the most stringent environmental requirements for pharmaceutical manufacturing.

Industrial gases are produced using one of two types of processes - cryogenic and non-cryogenic. As the name implies, cryogenic processes involve very low temperatures, in this case using a distillation process. Similar to the more familiar high temperature distillations involving organic chemicals (such as petrochemicals or alcohol), these separations are based on differences in boiling point between different gases. Non-cryogenic processes involve other differentiators, such as molecular weight. Cryogenic processes are used when high purity gases are required or when throughput is of concern.

Ceramics

Ceramics have numerous uses, both industrial and otherwise, many somewhat surprising (for instance, bullet resistant materials, as well as high quality cooking knives). Ceramics can be made from a number of materials, but most frequently are made from aluminum or zirconium oxides. These materials are formed into desired shapes via a number of techniques, such as isostatic pressing, extrusion, injection molding, and mechanical pressing. Following the forming process, parts are machined to get as close as possible to the desired end product before firing, as machining after firing is more complex and generally involves diamond tools. Finally, the material is fired, and finished - which frequently involves glazing with a glass material. In certain cases, such as in the production of ceramic knives, final sharpening has to wait until after the firing process, and thus requires diamond dust coated grinding wheels to create the necessary edge.

The raw materials for producing ceramics, such as aluminum oxide or zirconium oxide, are produced largely from mining activities with some level of chemical purification. In the case of aluminum oxide, a common process is known as the Bayer process, which involves taking bauxite (basically an aluminum oxide ore) and converting the available aluminum oxide to an aluminum hydroxide to facilitate separation, and then converting it back to aluminum oxide via heating.

Dyes and pigments

Dyes and pigments represent two different classes of coloring compounds. Pigments are generally insoluble in water as well as other solvents. They are generally suspended in some other media and that is applied to a surface. Dyes are soluble in either aqueous or organic solvents, and are frequently differentiated based on which solvent class they are soluble in.

Pigments can be either organic or inorganic. An example of an inorganic pigment is ultramarine, which used to be derived from mined lapis lazuli, but is now manufactured synthetically (aluminum silicate with sulfur impurities). Organic pigments, on the other hand are entirely synthetic, such as dinitroaniline orange (C17H13N3O3).

Dyes, on the other hand are almost entirely oganic in nature. Dyes are also almost entirely synthetic, with very limited production of naturally occurring dyes. This is due to both expense as well as the wider range of hues that were achievable with synthetic processes. The development of synthetic organic dyes in England in the 19th century ultimately became the foundation for essentially the entire organic chemistry industry within the Unites States, from pharmaceuticals to plastics.

Fragrances

Most fragrances are “essential oils”, either derived from plant and natural sources, or synthetically produced. Increasingly, due to environmental concerns, as well as expense, fragrances are being synthetically produced. Once the fragrances are manufactured, the perfumer then creates a blend of numerous different fragrances to produce a desired scent (some will have between 50 and 100 ingredients). Once this scent is created, for mass produced perfume, the recipe will be reproduced.

Given the significant number of compounds in a given perfume, analysis of the finished product can be relatively difficult, often involving 2D gas chromatography using heart cuts from the orthogonal separation. Mass spectroscopy is also used in conjuction with the chromatographic separation to further assist in analyzing the relative quantities of the various ingredients in the finished product.

Contract analytical chemistry

Contract analytical chemistry laboratories can provide a very broad range of services to other sectors of the economy. Frequently utilized in support of the chemical industry in general, they also provide critical services for the life sciences industry, agricultural industry, food manufacturers and the like. Even where a given organization has its own laboratories, a contract laboratory may be utilized as either a workforce extension, or to provide capabilities not available in house, and for which little or no justification exists for developing the capability in house. For instance, new pharmaceutical compounds often need detailed characterization prior to filing of chemistry, manufacturing, and controls portions of applications. For smaller companies, certain types of characterization methods, such as x-ray crystallography, circular dichroism, and the like, may not be within their internal capabilities.

Contract laboratories can therefore be placed into challenging situations in a couple of very different ways. One is with the need to provide what is a routine form of analysis (at least for the contract lab), but on a unique compound or class of compound where the laboratory may not have much experience. In these cases, the laboratory may be faced with a decision about the capturing of data. Do they use a generic set of data fields which apply to all samples for the same type of analysis, or do they attempt to be more granular. In the latter case, in order to provide appropriate service levels to the customer, rapid development of the data model must be undertaken so that the analysis can proceed in short order. The opposite problem may be for the laboratory that offers highly customized services, where method development is a key component of the service provided. This would require that any data capture would have to be designed alongside of the method, again in the interest of providing appropriate service levels. An option clearly remains for the utilization of highly generic data models, but it is hard to imagine that such data capture would be of much use.