Hilliard Emission Controls, Inc. 3100 Edloe Street Suite 350 Houston, TX 77027 888-621-3132       hank.hilliard@purgit.com

.

Vapor control on 100,050 bbl cap tank. This tank was designed for 15 psi. It had isoprene and was being cleaned for maintenance. When we started vapor control, the tank had approx. 8 psi. We recovered 5,000 gallons of isoprene and put the recovered material back in a pipeline segment. The purgit nitrogen system put nitrogen gas back in the tank to keep pressure in the tank, maintaining slight pressure on the tank at all times. Purgit does not need to pull air into a tank during cleaning because it uses a closed loop, and condensers can process inerted vapors, no oxygen required.

Gasoline tank with floating roof. 2 tanks had approx. 40% concentration gasoline vapors by volume. Condensed vapors and collected the gasoline in drums for recovery at the tank farm. Recovered about 500 gallons of gasoline.

Ammonia pipeline vapor control. Vaporized ammonia liquid from pig traps, sent the gas to the ammonia flare. Connected the knock-out tank to the pipeline so liquid would not carry over to the flare.

Pipeline vapor control. Near Denver, Colorado and Pasadena, TX Purgit set up a mobile flare, knockout tank, vaporizer, blower, hoses and other equipment to safely degas a pipeline with approx. 16,000 pounds of  isobutane liquid. Equipment was moved from one pig trap to another pig trap to control emissions at those sites.

On a LP pipeline we pulled a partial vacuum which caused the LP to volatilize making it easy to flare.

Vaporizer service. Furnished the PURGIT vaporizer to provide approximately 85,000# of CO2 gas for an local chemical facility. Operated the vaporizer for two 24 hour periods and delivered the gas at 100 deg. F.

Emergency vaporizer service.  At a refinery in Lake Charles, PURGIT vaporized ethylene and burned the gas in 2 John Zink vapor combustors. 

Tank vapor control & recovery. PURGIT performed cryogenic vapor control: to clean 5 gasoline tanks in Perth Amboy, NJ. The process recovered over 40 barrels of gasoline. Because of the unique nature of the PURGIT condenser we minimized NOx emissions and had no source of ignition in the tank farm.

For lease - PURGIT has a 1,000 gallon LP rated knockout tank. The tank has 4" ansi 150# flanges and a 2" drain. The safety valve is set at 260#.

Case history: 5,000 bbl MTBE (methyl tertiary butyl ether) fixed roof tank in Port Neches, TX the final LEL reading was 0.05% - even though the tank had 2' of catalyst on the floor.

A spherical tank in Texas City contained aldehyde. PURGIT cleaned the tank without adding any air or moisture. About 35 gallons of aldehydes were condensed into drums.

Barge transfer. In New Orleans, PURGIT has provided vapor control at a tank farm that handles chlorinated solvents during barge loading and tank cleaning.

Railcars. PURGIT conditioned 7 railcars for a Houston area chemical company. The job involved drying the cars with heated nitrogen gas. A device called a LectrodryerR was used to measure the humidity in the railcars to a dew point of -30 deg. F.

Emergency railcar service. At a refinery in Paducah KY, PURGIT burned ethylene to allow cargo to be transfered between 2 railcars. We also furnished the 3" transfer hose and the flare.

Inert gas service. PURGIT maintained an inert atmosphere in a railcar at a Houston rail siding over a 2 day period so that a moisture and static sensitive cargo could be safely loaded.

Equipment maintenance. Expensive machinery needed a small nitrogen flow to keep air and moisture out prior to shipment. Maintained nitrogen flow for 1 month at 2 cubic feet per hour.

Design.
Nitrogen tank pad system for a tank barge. PURGIT designed, built and installed this system for a marine customer. It keeps a very slight pressure (3" of water column) on the barge tanks to keep out oxygen and moisture.

Various jobs from hundreds of completed projects:

Chemical storage tank had layer of hydrocarbon floating causing air emission problems. Set up condenser to remove and condense the hydrocarbons - bringing the tank back into compliance. The vapor control did not disturb the tank operation which continued as normal. Recovered hydrocarbons were recycled.

150,000 bbl internal floating roof storage tank / Chloroform  A low temperature condensation system was perfect for this job. The vapors from the tank were drawn through the condensation coil with a high performance blower. The tank vapors were dropped to -35 or less and the chloroform condensate that collected in the bottom of the storage tank was transferred to drums. Condensation is better than combustion on chlorinated solvents because it does not produce hydrochloric acid as a byproduct, and there is zero NOx! No combustion flame in a the tank farm was a significant benefit of the condensation system.

130' diameter floating roof tank Gasoline storage tanks near a school needed to be cleaned for routine maintenance. PURGIT was called to set up an internal combustion engine vapor control device in advance of the tank cleaners. This device was selected for its compact design, quick setup and safety features. The tank vapor space under the floating roof was turned 4 times to meet the Texas emission control regulations. The volume of vapor moved was measured with a turbine meter.

Water treatment system Benzene in waste water created unacceptable levels of benzene in the working areas of the treatment facility. To overcome this problem, a tent was erected over the DAF and associated tanks. Then PURGIT set up a non sparking blower to suck the benzene out and push it to an enclosed flare. The level of benzene outside of the tents was kept to very low levels and the level of benzene pushed to the flare was over 1,000 ppm.

200,000 bbl external floating roof storage tank / Pygas  Levels of benzene in the pygas made vapor control especially important. Using the full PURGIT system, inert gas was inserted into the tank as the combustor withdrew and burned the VOC. This was done to create the safest and most efficient working environment..

150,000 bbl. internal floating roof storage tank / Gasoline At the largest commercial tank farm in Houston, set up the enclosed flare. There was a high concentration of gasoline vapor in the tank as a result of the heat of the July sun in Texas. A blower capable of handling flammable vapors moved the vapors from the tank to the flare. A detonation arrester and a water trap added levels of safety. The operation was completed in less than 12 hours meeting TNRCC regulations.

55,000 bbl. internal floating roof tank / Vinyl acetate At a La Porte, TX tank farm, set up the enclosed flare to burn VOC emissions from the tank. Once TNRCC regulations were met, the tank was opened and cleaned.

24" pipeline / Crude oil    At a Pasadena, TX pipeline terminal, set up the enclosed flare to burn hydrogen sulfide gas generated when the pipeline was purged with nitrogen. The PURGIT blower drew the H2S gas out of frac. tanks and kept it from escaping to the surrounding neighborhood.

104,500 bbl. internal floating roof tank / Gasoline  At a Pasadena, TX refinery, set up a single internal combustion engine to consume VOC tank vapors to the state minimum prior to opening the tank.

50,000 bbl. internal floating roof storage tank / Tertiary butyl alcohol. Used 3 internal combustion engines to move four volumes of dilution air through the tank to meet Texas Natural Resource Conservation Commission regulations for tank cleaning. Over 104,000 cubic feet of tank vapors were easily and safely controlled.

70,000 bbl. internal floating roof storage tank / Toluene. Used PURGIT engine to draw VOC vapors from tank during tank cleaning. At local tank farm, connected PURGIT vacuum relief and pressure relief valves, detonation arrester and engine to reduce VOC's to meet TNRCC regulations.

3 fixed roof storage tanks in the water treatment unit of a refinery. VOC gases were pushed out of the tanks as they were filled and emptied. A carbon adsorption system was used to control the VOC's, but the cost of the carbon was very high. PURGIT set up an enclosed flare to burn the tank gases as they were generated. Automatic controls monitor the temperature in the combustion chamber, maintaining continuous flare.

200,000 bbl external floating roof storage tank / Gasoline  Refinery personnel wanted to remove the mixer from the side of the tank. They wanted the tank to be safe for cold work during the removal and reinstallation process. Mobilized the PURGIT internal combustion engine device, hoses, detonation arrester, etc. to tank site and degassed tank. Reduced the levels of VOC to low level as directed by the maintenance dept.

14,000 bbl. capacity / 4 tank, double skin chemical tank barge / Perchloroethylene. Displaced the tank vapors with the PURGIT emission control system to the PURGIT vapor recovery unit. Filled the cargo tanks with CO2 through the cargo line, displacing the vapors out of the tank through the vapor line. The vapors were captured as condensate in a refrigerated vapor recovery unit, then transferred to drums for return to the manufacturer. The vapor recovery unit is an Edwards refrigerated unit capable of condensation temperatures as low as -120oF.

30,000 bbl. capacity / 3 tank, double skin tank barge / #6 Bunker oil. Inert three tanks for hot work to under 3% O2. Extensive deck work was required to change out multiple plates on the vessel tank top. No tank cleaning was required, and there was no oily waste to dispose of, saving the customer many thousands of dollars.

30,000 bbl capacity / 8 tank, double skin tank barge / #6 Bunker oil. Inert #2 P for hot work to under 8% O2. Broken frames found during a USCG inspection had to be welded to the tank side. Inerting allowed this work to be completed without cleaning the tank or moving the barge.

20,000 bbl. capacity / 8 tank, double skin tank barge / #6 Bunker oil. Inert all tanks for hot work to under 4% O2. Damaged frames in a void were replaced and welded without cleaning a tank. The job was started in the afternoon so the night crew could continue the work and complete it on schedule.

10,000 bbl. capacity / 3 tank, chemical barge / Hexane. Used the PURGIT system in the #1 cargo tank. Achieved 95% removal of hexane with 1.1 volume of CO2. By displacing the Hexane out of the cargo tank with carbon dioxide and routing the tank vapors to an engine vapor control device, the barge was cleared of the hexane vapors and very little supplemental fuel gas was needed.

25,000 bbl. capacity / 4 tank, double skin tank barge / #6 Bunker oil. Inert two tanks for hot work to under 3% O2. Work in a void next to the cargo tank required safety measures to prevent the chance of fire. Inerting was chosen because it is fast, inexpensive and the work momentum is not lost.

20,000 bbl. capacity / 4 tank, double skin tank barge / #6 Bunker oil. Inert #1 tank for hot work to less than 6% O2. Damaged frames in a void could then be replaced and welded without cleaning a single tank.

20,000 bbl. capacity / 8 tank, single skin tank barge / Marine diesel. Inert 4 tanks for hot work to less than 5% O2. A small fracture in the side shell was welded after the tank was inerted. This job was started and completed during the evening hours so the day crew could start early the next morning without delay.

20,000 bbl. capacity / 2 tank, (LFG) tank barge / Butadiene. Depressured 2 tanks from 60# to under 2# of tank pressure. When changing cargo from one product to another, the tanks must be swept and depressured. PURGIT mobilized a portable flare. The tanks were depressured and swept. Cargo was loaded without having to move the barge back to Houston.

20,000 bbl. capacity / 6 tank, double skin tank barge / Diesel fuel. Inerted four tanks for hot work, reduced the O2 to under 5%. This allowed the shipyard to repair a fracture on a steel plate near the cargo tank.

25,000 bbl capacity / 8 tank, single skin tank barge / #6 Bunker oil. Inert 5 tanks for hot work to under 5% O2. Inerted this barge so that miscellaneous fractures could be welded on the vessel deck.

25,000 bbl. capacity / 3 tank, double skin tank barge / Asphalt. Inert #1 tank for hot work to under 2% O2. Extensive work in the bow void over several days required thorough inerting. The heavy CO2 gas stayed in the tank very well, lasting a week.

20,000 bbl capacity / 4 tank, double skin tank barge / #6 Bunker oil. Inert all tanks for hot work to under 8% O2. Welded electrical support angles on the tank top.

25,000 bbl. capacity / 3 tank, double skin tank barge / Asphalt. Inert #1 tank for hot work to under 2% O2. Extensive work on the vessel bottom required the cargo tanks to be inerted for several days. A thorough sweep with CO2 lasted a week.

10,000 bbl capacity / 3 tank double skin, inland tank barge / Methanol. Used the PURGIT system to displace the methanol to a flare. Displaced the methanol out of the cargo tank with carbon dioxide and routed the vapors through the vapor line to a flare.

30,000 bbl. capacity / 8 tank barge / Py gas. Used the PURGIT system to displace the pygas to a flare. Nitrogen was inserted into the barge through the cargo line pushing the VOC tank vapors to the shipyard flare.

10,000 bbl. capacity / 3 tank barge / Ethylene dichloride  Filled high pressure cylinder on board the barge with 2,200 lbs. of nitrogen gas. The barge uses the nitrogen to keep the tank under slight pressure to keep oxygen out. Before opening the high pressure cylinder, purged the barge with nitrogen to condition the tanks.

30,000 bbl. capacity / 8 tank double skin, inland tank barge / Hexane. Used CO2 to safely pressure test the tanks without cleaning the barge. Filled the tanks with CO2 gas and applied 28" WC pressure for pressure test and issued PURGIT certificate of completion. Tested pipeline to 100# pressure.

15,000 bbl. capacity / 4 tank, (LPG) tank barge / Crude Butadiene. Depressured 4 tanks from 90# to 12# pressure. Nitrogen from a previous discharge remained in the tanks as a non condensable and kept the barge from loading. PURGIT met the barge in Port Lavaca, and safely flared off the nitrogen pressure at the dock without having to move the barge back to Houston.

50,000 bb. capacity / 5 tank, LPG ship / Propylene. Flared 5 tanks to remove nitrogen gas. Nitrogen gas used to inert the tanks, remove moisture and oxygen had to be removed to allow the ship's refrigeration compressors to work properly. Assisted Intership Services to prepare the tanks with propylene and flared the nitrogen and propylene. PURGIT met the barge in Lake Charles, and efficiently removed the pressure at the dock without the ship having to go to sea to vent or leave the dock.

(2) 22,000 bbl. capacity two tank Anhydrous Ammonia barges. Depressured both tanks and purged tanks with nitrogen. Tanks on these barges were due for an inspection. The customer wanted to do tank cleaning at a yard that does not have a flare. PURGIT sent it's mobile flare fully permitted for operation in Louisiana to do the vapor control. PURGIT provided nitrogen services.

22,000 bbl. capacity 2 tank Anhydrous Ammonia barge. Conditioned tanks with nitrogen to remove air, assisted customer to flood tanks with ammonia, flared nitrogen until ammonia is at proper level.

15,733 bbl. capacity 4 tank LPG pressure tank barge containing butane. Assisted in transferring remaining cargo to tank truck. Used the PURGIT method of emission control to displace the butane with carbon dioxide. Burned the butane in the PURGIT open flare. Reduced butane in tanks from saturated to 90% of the LEL with 3.2 volumes of CO2.

22,000 bbl. capacity tank barge with 8 tanks / Bunker oil Inerted all tanks for hot work. Minor deck items needed to be welded. Cleaning the tanks would have been expensive, so the vessel owner called PURGIT to inert, saving thousands of dollars in cost.

Return to the PURGIT web page