Residual Protective Life of Carbon Beds.
Abstract
Experiments are reported which show that the residual life of charcoal filters can be monitored by measuring the chromatographic retention time of a pulse of a probe gas. The retention times of several probe gases were shown to vary with the level of loading of filter-grade charcoals. Pittsburgh ASC and BPL charcoals were used as sorbents, dimethyl methylphosphonate and water as sorbates, and low-molecular-weight hydrocarbons and CO2 as probe gases. All experiments were carried out on laboratory-scale beds which simulated by using beds of the same depth operated at the same linear gas velocity, large-scale breathing-air filters. The variables investigated included: chemical nature and molecular weight of the probe gas, flow rate, temperature, and geometry of the bed. Results of the retention time measurement for residual life are given for the decrease in residual life with a constant DMMP feed level (0.1-mole % in He) flowing into a new filter and with a clean He feed flowing into a partially used filter. Two basic configurations for measuring the residual life of a filter are suggested, retention time directly on the filter and, second, a simulation mode using a commercial chromatograph. The method depends on the change in retention time per unit weight of charcoal as a function of sorbate loading. The loading-retention time dependence is associated with the change in the isotherm of the probe gas as a function of sorbate loading.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1977
- Accession Number
- ADA057693
Entities
People
- Alvin H. Weiss
- Ehud Biron
- Thomas Freund
Organizations
- Worcester Polytechnic Institute