A single-stage diaphragm compressor failed during boosting of high-pressure hydrogen ground storage banks. The compressor sources hydrogen from a 44 MPa storage bank as suction and discharges it at a stop set point of 85 MPa. The compressor capacity is 0.71 m3/min (25 scfm).

The original notice of failure was through an inter-diaphragm pressure indication and alarm. There should not be any pressure build-up between the layers of the diaphragm. Upon opening, hydraulic oil was found, leading to the assumption that the hydraulic-side diaphragm was leaking. Although spare diaphragms and seals were available for on-site repair, difficulty was encountered in attempting to remove the compressor nut above the diaphragms. Similar difficulties were encountered when the unit was returned view more

Overview

The catalyst in a dehydrogenation reactor, which was usually operated under a hydrogen atmosphere, was changed while the reactor was isolated from the peripheral equipment by closing a 20-inch remotely controlled valve. The hydrogen pressure in the peripheral equipment was set at 20 KPaG, and the reactor was opened to the atmosphere. Anticipating some hydrogen leakage, suction from the piping was accomplished with a vacuum device and, nitrogen sealing was performed. When the piping connections were restored after changing the catalyst, flames spouted from the flange clearance and two workers were burned. One cause of the fire was poor management of the catalyst replacement process.

Incident Synopsis

A catalyst exchange was carried out in a dehydrogenation view more

A rupture occurred in a 24-inch gas line in a reformer. The pipe contained hydrogen and carbon monoxide at a pressure of about 400 psi and a temperature of 930 °C. The ruptured section of pipe had a high-temperature alloy steel outer wall, a refractory liner, and a stainless steel inner liner. The refractory lining had been repaired several times before (including three months prior to the incident) because of localized deterioration and hot spots. The repair procedure consisted of cutting a section of pipe, re-pouring the refractory liner, and patch-welding the outer wall.

The first rupture occurred when the 42-inch-long welded section of the pipe suddenly blew out. On-site employees heard a rumble and observed a flame above the ruptured pipe. Before the torch fire at the view more

An anhydrous hydrogen fluoride (AHF) lecture bottle spontaneously exploded in a laboratory. No one was injured, but the lab was extensively damaged. The lecture bottle had split along its seam. Its cap and valve assembly were located to the immediate left.

Cause
The explosion was caused by hydrogen gas pressure build up in the cylinder. AHF comes in carbon steel cylinders as a liquefied gas under a pressure of 0.9 psi at 70 oF (i.e., the vapor pressure of the liquid). Though cylinders should be passivated with fluorine, which forms a protective coating, over time AHF may slowly react with the iron in a cylinder to form iron fluoride and hydrogen gas. The generation of hydrogen gas may produce cylinder pressures as high as several hundred psi.

A 2000-psia-rated gas cylinder (nominal size 10"x1 1/2") was being filled with hydrogen to a target pressure of 1500 psia. The cylinder suffered a failure at an indicated pressure of 1500 psia during filling. Investigation of the failure subsequently revealed that a faulty digital readout had allowed the cylinder to be over-pressurized. There were no safety consequences due to the failure and no damage to the facility or equipment. The cylinder was being filled in a test vault that was specially designed for the high-pressure burst testing of pressure vessels and components. While no over-pressure cylinders were released from the laboratory for use, this incident is being reported to address the potential and subsequent lessons learned.

Investigations revealed that the view more

A researcher was working with hydrogen storage materials in a laboratory. Several other researchers were working in adjacent laboratories.

The researcher had prepared a sample of aluminum deuteride, AlD3, by reacting lithium aluminum deuteride and aluminum chloride in diethyl ether. The actual composition/phase of the material synthesized was unknown, but the researcher had attempted to produce the gamma phase of aluminum deuteride. The synthesis steps used to produce the material were complete and the researcher attempted to seal the material in a glass ampoule for offsite shipment and analysis. The sample size was approximately 1 gram.

The ampoule with the sample had previously been placed under vacuum and had been isolated from the atmosphere. The process for sealing view more