INTERNATIONAL CLEANER PRODUCTION INFORMATION CLEARINGHOUSE

Case Study # 127

1.   Headline:  Recycling and sorption of CCl3F and TDI
     generated during the production of polyurethane (PUR)
     block soft foam.

2.   Background:  see below.

3.   Cleaner Production Principle:  internal recycling, solvent
     recovery

4.   Description of Cleaner Production Application:  The
     technology involves the sorption and recycling of harmful
     materials in process gases generated during the production
     of polyurethane (PUR) block soft foam.  Activated charcoal
     is used for removing CCl3F and TDI which are emitted with
     the exhaust air during the conventional production
     process.  Adsorption of TDI is an irreversible process,
     which eliminates the option of recovering the TDI.  The
     CCl3F, however, is recovered through regeneration of the
     charcoal bed with hot steam.

     Material/Energy Balance and Substitution

     FEEDSTOCKS:  Steam, electric power, cooling water,
     activated charcoal, exhaust stream

     WASTES:  CCl3F in purified exhaust air (<20 mg/m3), CCl3F
     in condensed aqueous phase (<0.01% by weight), TDI
     converted to innocuous polyurea on activated charcoal (no
     longer detectable)

     MEDIUM: Gaseous, water, solid

5.   Economics

     CAPITAL COST: 700,000 DM (1983 for plant capacity of
     30,000 m3 exhaust air per hour)

     OPERATING/MAINTENANCE: 557 DM/t of recovered CCl3F

     MONTHS TO RECOVER: 30

     DISPOSAL & FEEDSTOCK:  The recovery process is an addition
     to the process

6.   Advantages

     FEEDSTOCK REDUCTION:  1443 DM/t of recovered CCl3F

     WASTE PRODUCTION: CCl3F emitted is <20 mg/m3 compared to
     0-50 g/m3 without the recovery process (regulatory level
     is 300 mg/m3), TDI is now captured in the charcoal bed
     compared to emissions of 0-20 mg/m3 without recovery
     (regulatory level is 20 mg/m3)

     IMPACT: This sorption and recovery process achieves
     extremely low CCl3F emissions from the polyurethane foam
     manufacturing process and TDI emissions below the
     detection limit.  Additionally, CCl3F resources are
     recovered with this process.

7.   Constraints:  No information provided.

8.   CITATION/PAGE: Compendium on Low and Non-waste Technology,
     United Nations Economic and Social Counsel,  "Sorption and
     Recycling of Harmful Materials During the Production of
     Polyurethane (PUR) Block Soft Foam", Monograph
     ENV/WP.2/5/Add.117

9.   Keywords:  Germany, chemicals, polyurethane, recycling,
     soft foam, charcoal, ISIC 3513

10.  Reviewers Comments:  This case study was originally
     abstracted for the US EPA Pollution Prevention Information
     Clearinghouse.  It underwent a UNEP IE funded technical
     review in 1994 for quality and completeness. It was edited
     for the ICPIC diskette in July 1995.

( DOCNO: 400-116-A-329 )