Converting Oil Burner to Gas / Dual-Fuel for Boiler and Brand Make & Size Recommendation

[jamestan]

I just started in a small Indonesian rubber compound manufacturing company and one urgent task is to setup an unused oil Burner & boiler to power existing autoclaves.

Basically, owner signed contract for gas power supply line for a new pilot wire production facility within the area, but due to COVID-19, we are stuck with a half-done plant and a monthly fixed fee for unused gas. The autoclave in existing rubber plant runs on steam from coal-powered boiler, but we have an IHI boiler attached with Weishaupt oil burner that have been idle for 15 years.

Owner now wants me to either:
- Convert existing Weishaupt oil burner to either gas burner / dual-fuel burner and start using gas.
- Procure new gas burner and setup with existing boiler.


I'm hoping experts on eng-tips can lend me some wisdom, and would greatly appreciate if anyone can kindly answer these questions:

1a. Is it possible to convert Oil Burner to dual-fuel / Gas Burner? If so, how complex is the process, what items would you need and how long will it take?
- I'm asking because all Indonesian Burner service engineers we've contacted said it's better to buy new as converting is impractical / impossible and potentially risky, since it causes burner to deteriorate faster, creating operational issues. But I found some companies in UK and US claiming on their website that they offer these services reliably. Which one is true?


1b. Is this the exhaustive list of dual-fuel burner's pros and cons, or am I missing some stuff?
**Dual-Fuel**
*Pros:
- Flexibility to switch fuel types, depending on fuel price.

*Cons:
- Higher emissions.
- Needs larger space.
- Possibly lower efficiency.
- Possibly higher maintenance.


2. Based on your personal experience, what Burner & Boiler brands would you recommend, in terms of reliability, ease-of-maintenance and bang-for-buck (e.g like a Toyota or Honda)? I did some research and found that following brands have great reputations, and I would appreciate your opinions on them:
**Burners**:
- Riello
- Beckett
- Carlin
- Weishaupt
- Bntet
- Dunphy

**Boilers**:
- Ishikawajima-Harima Heavy Industries (i.e IHI; this is our boiler brand)
- Miura
- Bosch


3. How do you calculate burner's & boiler's actual efficiency values during operational use?


4. What burner size do you actually need for a 5 ton/hr steam boiler?
- Management wants to make sure that suppliers are not scamming us by selling overly-expensive equipment, and that the burner capacity is just right for the job. In my calculation, under 70% boiler efficiency assumption, seems like existing burner is slightly below capacity for the boiler. Is 70% efficiency value typical for an unmaintained boiler? I've attached my work below, and can provide pictures of the boilers' insides as well.

- Also, owner (who is also a non-engineer) said I shouldn't use 5 ton/hr in my calculations because in reality, we are not actually using the whole 5 ton/hr steam capacity during the rubber curing process. I'm not sure, but how do I check if this is true?

===================================================
Equipment List and Specs:
1. Weishaupt RMS10 Heavy Oil Burner
- Oil flow at 100 - 380 kg/hr.

2. Ishikawajima-Harima Heavy Industries (IHI) Boiler
- 5 ton/hr steam capacity.

3. Weishaupt L10T Light Oil Burner
- Oil flow at 100 - 360 kg/hr.

For both oil burners, the owner said they had been using high-speed diesel, rated at 45.5 MJ/kg.


Here's my calculation:
Since 1 ton/hr steam = 700kW boiler capacity
5 ton/hr steam x 700kW = 3500kW boiler cap.

Assuming 70% Boiler efficiency:
3500kW / 0.7 = 5000kW

Thus, theoretical required oil flow rate:
[5000 kW x 3.6 MJ/kWh] / 45.5 MJ/kg = 395.6 kg/hr


***Source***
1. For my calculation formula:

http://burnerexperts.eu/angielski/images/katalogi/katalogi_7.pdf

2. For theoretical energy density value of high-speed diesel / gasoil:

https://www.acea.be/news/article/di... calorific value of diesel,to 33.7 MJ/litre).

 

[amazing azza]

hi jamestan, so what did you end up going with?

**Boilers**:
- Ishikawajima-Harima Heavy Industries (i.e IHI; this is our boiler brand)
- Miura
- Bosch

Those names sound very familiar

 

[goutam_freelance]

Your calculation for fuel flow rate looks OK assuming 70% efficiency. But efficiency will depend of type of boiler i.e. whether economiser and air heaters are available etc.
Regarding use of oil burner for gas or dual fuel burning, it same is difficult if not impossible as gas has many times more volume than oil. So required fuel flow rate may not happen.

Engineers, think what we have done to the environment !

https://www.linkedin.com/in/goutam-das-59743b30/

 

[FacEngrPE]

I think I would start be asking weishaupt for a quote for boiler conversion as single fuel gas and dual fuel gas / oil. The response will get you a benchmark of the sorts of things you will need to look at.

Converting the existing burner is usually not possible..
The flame safety and air fuel ratio control will need changes or replacement.

Burner changeouts and conversions may result in needing to follow current emissions rules, check your nations rules, this might require using a low nox burner, and may make single fuel gas more attractive.

When firing with gas you need to be careful with the flame shape. Typically gas (CH4) has a larger flame than fuel oil.
The maximum firing rate may be lower for gas.