초록 ▼

An apparatus reduces the pressure in a volatile chemical tank ullage including a first conduit for connection to the volatile chemical tank ullage, a vapor extractor, a pressure sensor to detect the pressure in the volatile chemical tank ullage, a separation module having an inlet connected to the f

An apparatus reduces the pressure in a volatile chemical tank ullage including a first conduit for connection to the volatile chemical tank ullage, a vapor extractor, a pressure sensor to detect the pressure in the volatile chemical tank ullage, a separation module having an inlet connected to the first conduit, a separation membrane, a permeate outlet separated from the inlet by the separation membrane, and a retentate outlet, a second conduit connected to the permeate outlet for connection to the volatile chemical tank, a vapor pump associated with the second conduit for creating a low pressure in the separation module near the permeate outlet as to induce selected vapors to pass through the separation membrane, a vent associated with the retentate outlet to vent retentate to atmosphere, a VOC detector to detect VOC concentrations in the vent, and a controller to receive inputs from the pressure sensor and the VOC detector and output control signals to the vapor extractor and the vapor pump to pull vapor from the ullage when the pressure exceeds a pressure threshold and return permeate to the tank and permit relatively VOC-free air to be released through the vent, thereby reducing the pressure in the ullage.

대표청구항 ▼

A method for reducing the pressure in a volatile chemical tank ullage comprising detecting the pressure in the volatile chemical tank ullage, withdrawing vapor from the volatile chemical tank ullage when the detected pressure exceeds a pressure threshold, directing the withdrawn vapor to a first sid

A method for reducing the pressure in a volatile chemical tank ullage comprising detecting the pressure in the volatile chemical tank ullage, withdrawing vapor from the volatile chemical tank ullage when the detected pressure exceeds a pressure threshold, directing the withdrawn vapor to a first side of a separation membrane, creating a lower pressure on the second, downstream side of the separation membrane so as to induce selected vapors to permeate through said separation membrane, returning the permeate to the volatile chemical tank, permitting the escape of retentate from adjacent the first side of the separation membrane to atmosphere, detecting VOC concentrations in the escaping retentate, and controlling the rate of the vapor withdrawing step to control the concentration of VOC\s in the escaping retentate to maintain such concentration at a low level.