Safe Operating Procedure for Steam Explosion Pretreatment

Safe Operating Procedure for Fulton Electric Steam Boiler

Introduction The Fulton FB-075-L electric steam boiler provides high pressure steam for steam explosion pretreatment of biomass. This unit is rated at 7.5 HP and is currently configured for a maximum operating pressure of 600 psi, however, typical temperature requirements for the steam explosion pretreatment range from 30-260 psi (140-210 ºC). The following instructions provide guidance to the operator of the electric steam boiler. Do not attempt to start the boiler until all of this section has been read. Carry out the following procedure on initial start up and on every subsequent restart following a shut down.

SAFETY Potential Hazards  High pressure steam release  Burn hazard on or near boiler due to high temperatures  Electrocution due to high voltage (460 volts)  Boiler, pipe, or vessel failure

Emergency Shutdown A. Press the red push button located on right wall B. Close valve #2

Emergency Contact Phone Numbers  Dial 911  CE-CERT emergency room  Dr. CE Wyman 951-781-5703  John Wright 951-781-5758  Fulton Boiler Systems 315-298-5121

Thermal Burns Any burn that is extensive or severe, or which involves the eyes or face, should be considered serious. A burn involving the respiratory tract could be critical. Call the ambulance. Minor burns should be treated by washing the burned area with cold tap water. Wrapping the burned area lightly with a clean wet cloth or holding it in an ice bath will help reduce the pain. Do not use ointments or salves unless so instructed by a physician.

Training Contacts

Jaclyn DeMartini: Steam boiler/steam chamber Jian Shi: Steam boiler/steam gun Operation Procedure

Precaution

1) Do not operate boiler unless another person is in the area to check on you regularly. 2) Always wear face shield, leather gloves, and laboratory coat when operating the boiler. 3) Keep boiler area free of combustible materials (e.g.; paper) and flammables vapors and liquids (e.g.; gasoline). 4) Do not operate if floor or boiler is wet. Check floor drain under boiler.

Operation

1. Before you start: a. Ensure that the water tank outside the shed has at least 40 gallons b. If there is less than this, fill the white barrel (55 gallon/208.2 L capacity) near the shed with DI water from the lab. Add 20 g/barrel of Na2SO3 (0.1 g/L). Repeat the following steps once: c. Make sure that the following green valves are OPEN: c.i. Valve #1:valve outside leading from the water tank into shed c.ii. Valve #3:inlet valve on back of boiler c.iii. Valves #7 (7A-7D): valves to inspection glasses c.iv. Valve #9: valve to pressure gauge on top c.v. Valve #11: valve between pre-tank and high pressure pump in back c.vi. Turn-knob #13: shut off valve to the inspection glass on the pre-tank c.vii. Turn knob #14: valve to the inspection glass on the pre-tank d. Ensure that the following red valves are CLOSED: d.i. Valve #1: lever arm at top. Should remainin down position, as is. d.ii. Valve #2: main steam outlet valve d.iii. Valve #4: fast valve on left side d.iv. Valve #5: blow down valve on left side d.v. Valve #6: drain valve forfront inspection glass d.vi. Valve #8: air vent from rear boiler inspection glass… d.vii. Valve #15: Inspection glass on pre-tank valve. Turn counter-clockwise to close. 2. Flip Steam ‘General Control’ switch to ON 3. On back wall of the shed, turn the circuit breaker switch lever to ON 4. On the boiler, turn switch to ‘Auto’ for the pump 5. On the boiler, turn the ‘Boiler Heat Demand’to ON (If light on boiler switch does not go on, it means that the low water alarm has been triggered. This is not unusual when starting up the boiler, so push the “low water reset” button and make sure to monitor water level in boiler as it pressurizes (as stated in step #7) 6. Set pressure (in psi) by pushing the up and down arrows until desired pressure is displayed on bottom display, and then press Set. Note that the actual pressure in the boiler will be displayed on top, while the set pressure is below 7. Always examine front boiler inspection glass to make sure that the water level in the boiler is sufficient: as the boiler pressurizes, the water level should always remain above the 4 th bolt (if the water level is low, immediately turn the boiler heat demand to OFF) 8. Also examine pre-tank inspection glass in back to make sure that the water level in the pre-tank is sufficient. Water should remain above halfway point in glass.

To turn off boiler

1. Make sure that you close ALL valves that you may have opened, including valve 2 2. Turn the ‘Boiler Heat Demand’ to OFF, but do not switch anything else off yet 3. Allow the boiler to cool down while the power and pump is on 4. Once the boiler pressure is below 50 psi, turn the pump switch to ‘off,’ flip the ‘General Control’ “light switch” to OFF, and turn the circuit breaker lever to OFF 5. Turn fan off 6. If you used the hose, make sure this is turned off and returned to shed 7. Lock up shed after use Safety Operating Procedure for Steam Heated Pretreatment Using Steam Chamber Note - Max reaction temperature=180°C; safety release valve will open at a temperature of about 184.5°C

Running steam chamber

(Note that valves labeled as C1, C2, etc. are on the chamber itself) 1. Follow directions for starting boiler 2. Remove hoses from shed; the hose attached to the chamber drain should be positioned so that it is facing straight away from the shed; the long hose connected to the water inlet of the chamber should be connected to the water outlet 3. Make sure valve 20 (to the steam chamber) and all valves to the steam gun are closed 4. Prior to running samples, drain condensate from boiler: a. Open valve #2 b. Slowly open ball valve #19 only about ¼ of the way and allow condensate to drain into bucket below until steam is released (about 10-15 seconds) c. Close ball valve # 19 5. Pre-heat chamber before running samples: a. Connect thermocouple so temperature inside chamber can be monitored b. Make sure valves #C2, C3, C4, and C6 are closed c. Valve #C5 to the steam trap should remain open as well as steam inlet valve #C1 d. When ready to flow steam into chamber, open ball valve #20 e. Continue flowing steam until desired heating is achieved (chamber is usually allowed to pre-heat at set temperature for about 5 minutes) f. When done heating, close valve #20 g. After making sure that no one is near the hose’s outlet, open valve #C3 on chamber to release pressure. Release slowly at first, until about 1/3 open, then open remainder quickly h. Open valve #C4 to let any water drain from chamber i. After allowing chamber to reach atmospheric pressure, carefully open up chamber valve #C6. When doing so, stand back and to the side as some residual water may spill out onto the ground. 6. Running samples: a. Load tubular or well plate reactors into steam chamber with metal rod, positioning them as close to the steam inlet as possible (valve #C1) b. Repeat steps 5a-f c. After releasing pressure in chamber, close valve #C1 to prevent water from going up steam hose. Then open valve #C2 to allow water into chamber to quench reaction. At this point, position the hose outlet so that it will drain into large black waste container outside shed. d. After temperature in chamber has cooled down to <30oC, close valve #C2. Open Valve #C4 to drain water. e. If desired, after most of water has drained, valve #C4 can be re-closed, and the chamber can be re-flooded with water for further cooling f. After cooling, ensure valves #C3 and C4 are open and make sure that all water is allowed to drain from chamber. g. Finally, open valve #C6 to remove reactors

Steam chamber pressure vs. desired temperature

For a desired temperature of 180oC in steam chamber: - Set pressure to 125 psi when starting reaction - After temperature begins to stabilize (around 179.4oC), increase set pressure to 126 psi - Increase pressure by 1 psi whenever temperature begins to drop - Eventually level pressure off at 129 psi to achieve 179.8oC or 130 psi to achieve about 180.2oC For a desired temperature of 160oC in steam chamber: - Set pressure to 70 psi when starting reaction - After temperature begins to stabilize (around 69.4oC), increase set pressure to 72 psi and eventually to 73 psi (Steam Table: http://www.spiraxsarco.com/esc/SS_Properties.aspx)Safety Operating Procedure for Steam Explosion Pretreatment Using Steam Gun

Introduction

The steam gun pretreatment reactor is used for investigating biomass pretreatment requiring steam heating, particularly steam explosion pretreatment with or without catalysts. Steam can provide rapid heat up of biomass needed to the control temperature history, and rapid pressure release provides rapid cool down to terminate the reaction. Steam explosion can help disrupt the structure of cellulosic biomass, leading to an improved digestibility of the pretreated fibers because of the depolymerization, disaggregation and decrystallization. The typical operation temperature rage for the steam gun is 140-210 C (corresponding to approximately 30- 260 psi steam). The feedstock should be presoaked / pre-impregrated with just water or with some catalyst solution like dilute sulfuric acid of base prior to loading into the steam gun. The range of biomass loading for this gun is 200-450 g of dry weight.

Potential Hazards 1. High pressure steam 2. High temperature 3. Corrosive chemicals due to dilute acid or alkali 4. Noise from explosion

Biomass Preparation 1. Feedstock pre-weighted in batches of 200-450 g (air dried weight) in plastic containers or bags, and pre-impregnated with water or catalyst solution overnight 2. Use squeeze machine to reduce biomass moisture content if necessary 3. Biomass should have moisture content of ~40-70% for best pretreatment performance

Prerequisites 1. Wear coveralls, goggles, face shield, and leather gloves 2. Ensure that steam boiler is on and set at the pressure demanded for steam explosion 3. Read the schematic diagram (Figure 1) for the steam gun system carefully as posted on the wall 4. Check the labels for all the valves of this system

Operation Procedure for Steam Gun (Pre-cautiuon: wear heat-resistant glove and face shield all the time) Preheating 1. Check/set valve positions; be sure that valves SG-1, SG-2, SG-3, SG-4, #20, SG-8 and SG-RM are closed 2. SG-6 should be always open 3. Open valve #2: main steam outlet valve 4. Open #19 slowly to drain condensate water from the reservoir, and then close #19 5. Open SG-1 to let steam into jacket of the steam gun to reheat the steam gun body for 2-4 minutes, leave SG-1 open during pretreatment 6. With gun empty, install reactor cap (steam gun lid) and ensure that the Teflon gasket is properly seated 7. Tighten retaining clamp nuts to 25 ft. lbs. using torque wrench 8. Close SG-7, open SG-2 and then open SG-3 to pressurize gun body with steam to the target pressure corresponding to the demand temperature 9. Close SG-2, make sure SG-RM and SG7 is closed, open SG-4 10. Stay outside the gate, pull Remote Switch to open SG-RM to release condensate 11. Repeat opening SG-RM at least twice to ensure that the gun is fully depressurized and emptied

Pretreatment 1. Ensure that the sample collecting heavy duty plastic bag is fixed firmly to the circular holder 2. Ensure that the release Nozzle is firmly connected to steam gun outlet 3. Open SG-7 4. Disassemble reactor cap by removing brass nuts and clamp 5. Remove cap and hang on wire to the side 6. Load the pre-impregnated biomass feedstock through reactor top 7. Reinstall reactor cap making sure the Teflon gasket is properly seated 8. Tighten retaining clamp nuts to 25 ft. lbs. using torque wrench 9. Close SG-7, SG-RM, and SG-4 10. Open SG-2 to pressurize gun body with steam to the target pressure corresponding to the demand temperature 11. Slowly open SG-7 to purge air or condensate out of steam gun, close SG-7 12. Hold for desired pretreatment time 13. About 30 seconds before the end of the cooking time, close SG-2 14. Make sure SG-RM and SG-7 is closed, open SG-4 15. At the end of the cooking time, stay outside the gate; pull Remote Switch to open SG- RM to discharge the cooked biomass into the collector 16. Repeat opening SG-RM at least twice to ensure that the digester is fully depressurized and emptied 17. Allow enough time for venting steam, especially for dilute acid pretreatment 18. Close SG-RM, SG-4, to prevent the possibility of steam entering the collector while operators are opening the collector

Repeat the above steps for the next run 19. Collect pretreated biomass, and close bag with cable tie 20. Allow enough time for cool down and washing