CaO

Also quicklime, unslaked lime, and calcium oxide. Hydrated lime is calcium hydroxide (Ca(OH)2).  

Properties Commercial grades Uses Manufacture White to grayish-white solid. Reacts with water to form calcium hydroxide. Commercial lime is available in lump, pebble, ground, and pulverized forms. One of the oldest commercial chemicals. Used in hundreds of applications. The most important uses are for making steel and chemicals, water treatment, pollution control, pulp and paper, and construction. Limestone (calcium carbonate, CaCOj) from mines or quarries is heated in a kiln (calcined). 

Suppliers Barium Chemicals, Bruchem, Chemical Lime Co., Coyne Chemical, Kraft Chemical, Austin White Lime Co., Cutler-Magner Co., Mississippi Lime Co., Los Angeles Chemical, others. 

Lime has been manufactured for more than 2000 years and was the product of one of the first chemical processes used in the U.S. by the early settlers (the manufacture of rum being another). The many uses of lime are so varied that limestone and lime production are greater than any other natural substance. It is a low-cost commodity in the U.S. because there are limestone deposits in many parts of the country. Lime plants are always close to the limestone source in order to minimize freight costs. 

Ammonia is a colorless gas with a suffocating, pungent odor. It is readily liquefied under pressure. The gas is very soluble in water to produce ammonium hydroxide, also known as ammonia water or aqua ammonia. 

---

Historically an earth was a non-metallic substance, nearly insoluble in water and unchanged on heating. The alkaline earth oxides, e.g. CaO, have an alkaline reaction in addition to being clearly earths . 

Monitoring and control of the production process will be performed by a combination of instrumentation and control equipment plus manual involvement. The level of sophistication of the systems can vary considerably. For example, monitoring well performance can be done in a simple fashion by sending a man to write down and report the tubing head pressures of producing wells on a daily basis, or at the other extreme by using computer assisted operations (CAO) which uses a remote computer-based system to control production on a well by well basis with no physical presence at the wellhead. 

Computer assisted operations (CAO) involves the use of computer technology to support operations, with functions ranging from collection of data using simple calculators and PCs to integrated computer networks for automatic operation of a field. In the extreme case CAO can be used for totally unmanned offshore production operations with remote... 

By providing more accurate monitoring and control of the production operations, CAO is now proven to provide benefits such as ... 

The cost of implementing CAO depends of course on the system installed, but for a new field development is likely to be in the order of 1 -5% of the project capital expenditure, plus 1-5% of the annual operating expenditure. 

An example of an application of CAO is its use in optimising the distribution of gas in a gas lift system (Fig. 11.3). Each well will have a particular optimum gas-liquid ratio (GLR), which would maximise the oil production from that well. A CAO system may be used to determine the optimum distribution of a fixed amount of compressed gas between the gas lifted wells, with the objective of maximising the overall oil production from the field. Measurement of the production rate of each well and its producing GOR (using the test separator) provides a CAO system with the information to calculate the optimum gas lift gas required by each well, and then distributes the available gas lift gas (a limited resource) between the producing wells. 

Artificial lift techniques are discussed in Section 9.6. During production, the operating conditions of any artificial lift technique will be optimised with the objective of maximising production. For example, the optimum gas-liquid ratio will be applied for gas lifting, possibly using computer assisted operations (CAO) as discussed in Section 11.2. Artificial lift may not be installed from the beginning of a development, but at the point where the natural drive energy of the reservoir has reduced. The implementation of artificial lift will be justified, like any other incremental project, on the basis of a positive net present value (see Section 13.4). 

Brunauer and co-workers [129, 130] found values of of 1310, 1180, and 386 ergs/cm for CaO, Ca(OH)2 and tobermorite (a calcium silicate hydrate). Jura and Garland [131] reported a value of 1040 ergs/cm for magnesium oxide. Patterson and coworkers [132] used fractionated sodium chloride particles prepared by a volatilization method to find that the surface contribution to the low-temperature heat capacity varied approximately in proportion to the area determined by gas adsorption. Questions of equilibrium arise in these and adsorption studies on finely divided surfaces as discussed in Section X-3. 

Cao J and Voth G A 1995 A theory for time correlation functions in liquids J. Chem. Phys. 103 4211... 

Irvin J A and Dagdigian P J 1980 Chemiluminescence from the Ca(4s3d D) + O2 reaction absolute cross sections, photon yield, and CaO dissociation energy J. Chem. Rhys. 73 176-82... 

T. Y Cao, Conceptual Development of 20th Century Field Theory, University Press, Cambridge, UK, 1997. 

Some carbonates are important industrial chemicals. Calcium carbonate occurs naturally in several forms, including limestone, and is used in the production of quicklime, calcium oxide CaO, slaked (or hydrated) lime, calcium hydroxide Ca(OH)2 and cement. 

---