CEH Report
Table of Contents
Abstract
Hydrochloric acid (HCl) is produced in anhydrous form and as a solution containing 65–69% water. Typically, anhydrous HCl is produced as a coproduct of organic chlorination reactions, while muriatic (liquid) HCl can be produced synthetically by burner or as a coproduct. Most anhydrous HCl is generated and consumed captively on site or by pipeline from the manufacture of vinyl chloride monomer from oxychlorination of ethylene dichloride. Other large anhydrous HCl–producing applications include production of chlorinated methanes and ethanes, the isocyanates TDI and MDI, and fluorocarbons. About forty processes generate HCl as a coproduct and about 110 chemical manufacturing processes utilize hydrochloric acid as a raw material.
Hydrochloric acid is an integral part of the worldwide chlorine industry. Most of the HCl produced in the United States, Western Europe and Japan is generated as a by-product in the manufacture of a wide variety of organic chemicals via chlorination reactions. This supply depends largely on demand for the primary products. A significant amount of by-product HCl is generated when ethylene dichloride (EDC) is cracked to make vinyl chloride monomer (VCM). This HCl is usually recycled back to the EDC reactor for additional oxychlorination and for the most part does not enter the commercial market. Similarly, most of the HCl generated in the production of chlorinated C1s (primarily methylene chloride and chloroform) is recycled to produce additional methyl chloride. By-product HCl from isocyanate and fluorocarbon production cannot be as readily recycled because of logistics and/or purity concerns and most is supplied to the merchant market, although this practice is changing.
The following pie chart shows world consumption of hydrochloric acid (100% HCl basis):
International trade in anhydrous HCl is negligible, while trade in muriatic acid is minimal because of transportation costs, the exception being across borders close to production sites. Prices for HCl had been fairly stable, but in recent years have been quite volatile. Production of coproduct HCl has declined, in part because of the economy, leaving shortages of HCl. In the future, increased amounts of burner acid will be produced in some regions to meet demand. Worldwide growth is forecast at slightly over 2% annually during 2008–2013. The Asian market will grow the fastest at 2.6% per year, with China growing at 4.4% annually. In 2008, the largest consuming countries were the United States, Europe (EU 27), and China. These three regions accounted for over 67% of global consumption. Asia (excluding Japan) accounted for nearly 37% of all consumption.