| Replacement of Benzene with N-Butane in the production of Maleic anhydride | Italy | 1992 | Full scale |
MANUFACTURE OF CHEMICALS AND CHEMICAL PRODUCTS # 22
Background
The case study was completed in 1992. The process is called ALMA PROCESS and was commercialised in 1989. The mother company, Alusuisse sold the technology in Japan, India, Austria, South Korea, and Taiwan. The largest industrial plant (35,000 tons/year) using the technology has been successfully in operation since January 1985 in Yokkaichi, Japan.
Cleaner Production Principle
New technology
Cleaner Production Application
Cleaner production is the result of a new process and plant based on catalytic oxidation of n-butane with air on a fluidized bed reactor. Exothermic heat of reaction is removed from the reactor producing high pressure steam in coil bundles located within the fluid bed. The steam is used for internal energy needs requirements.
Environmental and Economic Benefits
From an environmental point of view, the process produces about 1/3 of gaseous products without benzene and benzene derivatives and less CO and CO2; it uses only 10% of process water and, moreover, produces less liquid waste (1.6 m3/ton of maleic anhydride Vs 3.6 m3/ton referred to benzene process). From an economic point of view, maleic anhydride production cost is lower (60%) compared to that of the benzene process. The maleic anhydride grade is 99.9999%, as specifically required in some applications. There is an aqueous effluent reduction and process water reduction due to the use of patented solvent recovery.
The benefits are listed as follows:
| Reduction in gaseous emissions; |
| Reduction in aqueous effluents, (effluents can be treated in a biologically conventional treatment plant and have a hydrocarbon content of about 0.04 kg/kg, before treatment); Reduction of process water, due to the use of patented solvent (diisobutylexahydrophtalate) instead of water for maliec anhydride recovery; |
| Solvent consumption is minimized; |
| water and energy savings because two unit operation is not required; |
| maleic anhydride is recovered; |
| energy savings due to a less complex process and to the recovery of heat to produce steam and energy for internal use; and |
| Reduction of involved risks from the benzene cycle (production, storage, transport, and handling) by using N-butane instead of benzene. |
Constraints
None reported.
Contacts
Review Status
This case study was submitted to UNEP IE in 1994 by ENEA. It was reviewed and edited by UNEP IE in July 1995.
Subsequently the case study has undergone a technical review by Dr Prasad Modak at Environmental Management Centre, Mumbai, India, in September 1998.