Feature Article

Chlor-Alkali Industry Perspective

Process Overview

Chlorine and caustic soda (sodium hydroxide) are produced simultaneously when electricity is used to break apart a standard table salt (sodium chloride) molecule. The process starts with salt being dissolved in a water stream to form brine. The brine is then treated to remove any impurities. The treated brine is then fed to the cell room - the place where the electrolytic cells reside. The cells are like big batteries, with a positive anode and a negative cathode. The electricity is passed through the brine solution. At the anode, chlorine gas is generated. The chlorine is then cooled, dried, compressed, liquefied, and stored. At the cathode, caustic soda and hydrogen gas are generated. The caustic soda is forwarded to an evaporation system where the excess water is removed. The hydrogen is cooled, dried, and compressed. The hydrogen is normally fed to an onsite boiler for steam generation.

Capacity

The current world capacity of chlorine is approximately 125,000 tons/day. Chlorine is the 7th or 8th largest volume chemical manufactured in the world. The North American chlorine producers are currently running 92-95% of capacity. Several new plants have been brought online over the last several years, and additional plants are in the conceptual phase. The world capacity is divided up as per the following:

45% Europe

35% North America

10% Japan

8% Asia and Pacific

1% Middle East

1% Africa

Chlorine markets have been estimated as follows:

40% Plastics (EDC, PVC, VCM)

20% Miscellaneous Inorganic

15% Miscellaneous Organic

10% Pulp and Paper

7% Water Treatment

2% Solvents

1% Pharmaceuticals

Caustic soda markets are estimated to be:

50% Chemical Manufacturing

24% Pulp and Paper

11% Miscellaneous Industrial

7% Cleaning Products

4% Petroleum and Natural Gas

2% Celluloses

2% Cotton Production

Growth Forecast

Historically, the Chlor-Alkali products, chlorine and caustic, have grown at 1-2%/year. In the early 1980's, there was negative growth due to the recession. There was relatively steady growth through the 1980's. In the early 1990's, there was again some flat to negative growth as the industry adjusted to the phasing out of direct chlorine bleaching in the forest products industry (due to the Cluster Rules). During this time, there were a number of plants that closed in the Northwest, Canada, and Northeast, while new plants were coming online in the Texas and Louisiana. The market is fairly balanced right now, but there are several industry surveys that indicated a shortfall in the industry as early as 2001.

Technology

Chlor-Alkali plants are divided into three main technologies: mercury, diaphragm, and membrane. Any new plant is built with membrane technology because of the reduced energy consumption and absence of environmental issues.

The Chlor-Alkali industry has a technical trade organization, The Chlorine Institute. This organization has over 100 published pamphlets on industry best practices, ranging from recommended practices on railcars to emergency response plans for chlorine facilities to atmospheric monitoring equipment for chlorine.

Safety

A Chlor-Alkali plant is regulated by OSHA as a Process Safety Management (PSM) facility. This requires that the facility fully embrace all 14 elements of the federal rule. Sections include employee participation, process safety information, process hazard analysis, operating instructions, training, startup safety reviews, mechanical integrity, management of change, and compliance audits.

Chlor-Alkali facilities are also required to develop and share with near neighbors a Risk Management Plan (RMP). This regulation outlines that a plan be prepared that discusses worst-case scenarios and an accident release history.

The Chlorine Institute initiated and maintains the framework for a national chlorine response network, CHLOREP. The network is made up of a coalition of member companies who respond to transportation or industrial incidents. This network also provides mutual aid to local emergency response organizations (fire, police, etc.)

The industry tracks and reports all industrial accidents and releases. Significant events are reviewed at the twice-yearly Chlorine Institute meetings so that learnings can be shared. Safety awards are given each year to facilities that demonstrate significant achievement and improvement. The chemical industry continues to have one of the lowest injury rates of any industrial sector.

The Bureau of Explosives (BE) collects data from the Department of Transportation (DOT) about problems with hazardous chemical shipments. For the last quarter of 1998 and the first quarter of 1999, the BE reported for chlorine cars: 5 leaks in 52,000 shipments. Although none of these leaks resulted in any injuries or evacuations, one leak is considered unacceptable.

For more information about Universal Dynamics and our work in the Chlor-Alkali industry, Contact Us or go directly to our Chlor-Alkali Industry page.

Back to the Feature Article main page