GraphitizationFurnace_QnA_20200701.docx

Graphitization Furnace Questions and Answers

June 30, 2020 NASA hosted an information session on June 30, 2020 related to RFQ 80LARC20Q731649 for a graphitization furnace via Microsoft Teams. Questions and answers are summarized here as well as additional ones received via email. For a recording of the call contact Lynnis Roberts at Lynnis.roberts@nasa.gov.

Q: Is the target to get to 2800C in 4 hours?

A: Yes, the goal for the heating portion of the furnace run is to reach 2800°C in four hours. This is the source of the 12 degrees a minute spec. This is an average goal.

Q: The total cycle is 10-12 hours, correct?

A: For our current needs our cycle is a 4 hour heat up to 2800°C with a 2 hour hold, then cooling. We do not have a cooling rate specified yet, but would expect it to take an overnight cool down to reach a safe opening temperature. We have a spec for a 12 hour hold so that in steady state there are no thermal issues. For example, we would not want to have to turn it off after 2 hours of hold because we overheat the power supply. This system is for research so we do not know all the future applications some of which may require longer holds at maximum temperature.

Q: Is the 12 hour spec the soaking at the maximum temperature or the total time for the cycle?

A: The 12 hours hold is so that the system is not designed with thermal soak issues. For our typical cycle for the tubes systems we are assuming we’ll need 3 to 4 hours to purify the atmosphere, vacuum purge cycles with inert gas, followed by 4 hours heating, 2 hours hold, so around 10 hours. If we need a controlled cooling that would extend the cycle time. We’d like to be able to do a heat treatment in one shift.

Q: Could you describe the building the furnace will go in?

A: We have a fairly large space and can rearrange things to accommodate the size of the furnace within reason. The ceiling height is estimated at 14 feet (This has been measured since the call). As far as power requirements, we don’t have the exact power availability but we will make sure the proper utilities in place to meet the needs of the system. There are two cooling towers in place already with cool water plumbed in. As far as gases we anticipate using compressed gasses as well as shop air if needed for valve operations.

Q: Which PLC control system are you looking for?

A: No preference.

Q: Do you already have a cooling system?

A: Yes, there are two cooling towers. We believe they are sufficient won’t know for sure until the furnace system is designed.

Q: Explain why 3 pyrometers are needed for a single control zone?

A: To specifically measure variations in temperature in the hot zone.

Q: The spec says there needs to be a positive pressure but is there any flow requirement?

A: The flows required are going to depend of the furnace design. A 1 cubic meter furnace would need to flow about 33 SLPM to fill the chamber in 30 minutes. During heat up, the expanding gas will have to be vented, and there is a pretty large volume increase from 20° to 2800°C. Assuming a 4 hour heat up it would need to vent about 2500 cubic meters (assuming the average chamber temperature is 1400°C with Ar fill) or about 10 SLPM. During cool down it would need to make up for the shrinking gas volume. For a 4 hour cool down the flow would need to be around 10 SLPM. During the actual run the gas flow is just nominal as the heating will cause an overpressure to whatever level the relief system is set too. The system we run the most now, is 0.1 cubic meter and we run 2 SLPM of Ar in it, no problems on cool down. Up to 50 SLPM for backfilling.

Q: In which temperature range is the 12°C/min required?

A: 12°C per minute refers to the entire controlled range up to 2800°C

Q: Which heating rate is required for temperature > 2000°C?

A: The controlled temperature ramp is only required at temperatures at which the optical pyrometers can provide control, depends on pyrometer chosen (up to bidder) but could be for example from 1600°C and up. Below the control temperature the rate is not specified but we would expect any system capable of 12° per minute above 2000°C should not have an issue below that temperature.

June 25, 2020 Q: When you say you are looking for installation do you mean making all the utility connections like gases, water, and electricity?

A: NASA will prepare the utilities to meet the needs of the selected design. We will base the necessary connections and power requirements on the operating requirements outlined in the selected contractor’s proposal and aim have the connections ready at the time of installation for the contractor to connect the furnace into.

Q: Question about the proposal format, specifically the past performance section. We have not had any direct government contracts in the last three years, but have subcontracted on a few projects. Is that worth listing or should we just say not applicable?

A: It is not necessary that these three past jobs be federal prime contracts. Narratives of relevant subcontract work would be acceptable as well as commercial contracts.

Q: In the specification, item 17 describes "Onsite installation shall be included". Can you define more clearly what you are expecting?

A: If the furnace delivered requires more than just us being able to plug a fully assembled system into the socket, then we would appreciate having the vendor send someone who can properly assemble the system and prove that it operates properly before we accept the system. The visit can also be used to train users on how to operate the system since training is also one of the requirements.

Q: The document "Furnace Instructions to Vendors" page 2 under Evaluation Criteria - Factor 1b "Also, the offeror shall discuss in detail its ability to meet the option A". What is option A? Also under Factor 3 item b "Firm Fixed Price for option item A". What is option A?

A: Option A refers to the last sentence in the specifications, which should be a separate “add-on price” from the main proposal. This means the government may or may not choose to add this feature if the proposal is selected. Option A: “The bid will also include an option to operate the system with three temperature zones to allow for more precise control of the entire hot zone.”

June 16, 2020 Q: We have been reviewing the solicitation and did not notice mention of a mass of the product to be cycled which would help in sizing the power supply.

A: Our estimate is that the part mass will be in the range of 60 kg retort with lots of room around it to about as much as a 130 kg solid part.

June 15, 2020 Q: What is the exact material they will be processing in it? They say a carbon based. We need a composition of the material used material cert.

A: Carbon composites. This is for materials research so we don’t have a specific material cert.

June 11, 2020 Vendor questions generated from market research and answers:

Q: Vendor asks NASA’s preference among a resistance heated furnace design operating at 2600°C or an induction heated furnace design reaching 2900°C.

A: NASA has a preference for the lowest cost design however we do desire the operating temperature to reach 2800°C.

Q: What is NASA’s current furnace set-up?

A: Our current high temperature system has a working hot zone of about 11 wide x 15 deep x 10 tall inches, Max temperature of 3000°C. Not certain on the power but think it is in the ballpark of 70 to 100 KW input.

Q: In what configuration are you looking for horizontal or vertical?

A: Either vertical or horizontal is fine, whatever is lower cost.

Q: Can the materials to be graphitized be loaded vertically?

A: We have no preference for vertical or horizontal load, and prefer the lowest cost option that meets the specifications.

Q: Do you expect to flow gas through the furnace, or just pull a deep vacuum even if it is multiple purge and vacuum cycles, to operate under partial pressure, or positive pressure?

A: We expect to purge the furnace with a continuous flow of inert gas while operational. Mass flow control is required. Typically these types of furnaces operate under a slight positive pressure, past systems have been about ¼ to ½ psig. We have not run this large of volume furnace before but our current systems operate at 1 or 2 liters per minute of purge gas during operation.

Q: I noted the pumping requirements which can certainly be achieved however if the plan is operate the system at the indicated level of vacuum the insulation package and hot zone will deteriorate faster than normal. If the vacuum is meant to be utilized at lower pressures (say below 2000°C) then it’s not an issue.

A: Vacuum is intended only for use in aiding the purging of the furnace of air, i.e. cycles of vacuum <100 torr back fill with inert gas. The furnace will not be operated under vacuum.

Q: For a system with this temperature I would assume a 3 phase system right off the bat.

A: Yes, we expect a three-phase system. 3 phase 460 Volts is typical in our laboratories. Higher voltage lines can be installed if required.

Q: Are there any material considerations that you cannot use?

A: Will be used for heating carbon-based materials; no special considerations for material construction that we are aware of.

Q: I am assuming you would have or would get the power needed for this system A: Yes, once we decide on a system, we will wire the laboratory to meet the power requirements.

Q: Please elaborate on “The final system design shall be approved by NASA Langley Research Center’s Information Technology Acquisition Management (ITAM) prior to contract award.”

A: ITAM may require copies of software from the selected vendor for testing prior to award. Their main concern is the compatibility and safety of IT (if any) that will interface with other NASA systems rather than the physical and functional aspects of the proposed furnace design.