FAQ

Common problems of gasifier

03.20, 2021
Frequently Asked Questions (FAQ)
1. What does DY stand for?
DY stands for the abbreviation of Dianyan, which is the brand name of [Dianyan Biomass Energy] products.
BGPS stands for [Biomass Gasification Power Generation System] Biomass Gasification Power Generation System.
2. How does Dianyan use biomass materials to produce electricity?
The biomass raw materials enter the Denken gasifier system through the conveying equipment. The temperature in the gasifier is about 800-1000°C. The biomass raw materials are pyrolyzed and gasified in a high-temperature and low-oxygen environment to produce [biomass gas]; these After being purified and cooled, biomass gas enters the gas engine unit as fuel (for example, a four-stroke spark plug ignites the gas unit) to generate electricity.
3. Apart from gasification, what other effects does biomass have on us?
In addition to gasification, biomass can also be used as boiler fuel, anaerobic fermentation produces biogas, solid fuel production, ethanol production, building materials and so on.
4. What are the advantages and disadvantages of biomass gasification and other application methods?
a. Direct combustion: low investment, but the overall efficiency is very low;
b. Boiler fuel: technically feasible, but not economically feasible. Biomass can be effectively used for large-scale boilers> 6MW. In addition to the high initial investment, a large amount of biomass raw materials is required to run a >6MW boiler plant, which results in very high transportation costs for biomass materials, so it is not suitable for small and medium-scale applications ;
c. Biogas production: The biogas produced from biomass is relatively clean, and the calorific value of the biogas is also quite high, but the gas production rate is very low, so it is difficult for commercial applications;
d. Production of solid fuels: The production of solid fuels requires a lot of energy and mechanical wear and tear, and it is relatively strict to enter the solid fuel industry;
e. Production of ethanol: There are already technologies for the production of industrial ethanol using biomass, but the initial investment is huge, the operating cost is very high, and a large amount of biomass materials are required; it is only suitable for large-scale production, and it is very difficult to apply to small and medium-sized production;
f. Biomass gasification: The conversion efficiency of biomass gasification is reasonable; biomass gas can be used for power generation, gas fuel for boilers, and other heating applications; however, the gasification system has certain complexity and biomass gas heating value It is not high, and the gas produced is not easy to store.
5. What kind of biomass raw materials does Dianyan use?
General agricultural and forestry wastes and processed scraps, such as straw, rice husk, wood chips, palm husk, rice straw, cotton stalks, fruit husks, etc.;
6. What are the requirements of Dianyan for biomass raw materials?
Dianken uses fluidized bed and fixed bed gasifiers. Different furnace types require specific dimensions and moisture content of biomass raw materials.
7. What is the consumption rate of Dianyan's biomass raw materials?
The consumption rate of biomass raw materials with different calorific value is different, and the water content of biomass raw materials is different, and the consumption rate is also different;
For example, the consumption rate of wood chips is 1.2~1.5 kg/kWh, and the consumption rate of rice husk is 1.3~1.6 kg/kWh.
8. Compared with other biomass gasification systems, what are the advantages of Dianyan?
a. Complete system: Dianyan can provide a complete set of biomass power generation system services.
b. Modular design: the amount of civil engineering is small, the area is small, and the installation speed is quick and convenient.
c. Circulating water: The cooling water can be recycled and there is no secondary pollution.
d. High-voltage electrostatic decoker: low gas tar content, tar content <20mg/Nm3.
e. Service: Dianyan provides comprehensive technical support and perfect after-sales service.
9. What are the main components of biomass gasification for power generation?
a. Biomass feedstock system
b. Biomass gas gasification system
c. Biomass gas purification system
d. Circulating water system
e. Gas engine and generator system
According to customer requirements, we can provide [waste heat] recovery, remote control, etc.
10. What are the important components of biomass gas?
The gas composition changes according to different biomass raw materials, the water content of the raw materials, the load of the gasifier, etc.; the main components of the general biomass gas are as follows:
N2: 54-60%
CO2: 10-16%
CO: 12-18%
H2: 3-7%
CH4: 4-8%
CnHm: 1-1.4%
11. Is biomass gas toxic?
It is toxic because the CO (carbon monoxide) and CH4 (methane) in the fuel gas are harmful to the human body.
12. Why should we cool down the gas?
• In order to meet the requirements of gas engines for gas fuel
• Increase the energy density of gaseous fuels
13. Why do we need to remove dust and tar from biomass gas?
In order to avoid damage to the gas engine cylinder, piston ring, and igniter (spark plug), etc.;
In order to avoid blocking the gas pipeline.
14. Why use a gas-water separator?
The gas-water separator can separate the water droplets and dust in the gas from the airflow, and at the same time provide a buffer for the gas system, which can reduce the impact of gas pressure fluctuations on the engine.
15. Why use a safety water seal?
• The safety water seal is a safety device to avoid excessive gas pressure in the system.
• When the gas pressure is too high or required for operation, it is vented and ignited.
16. What are the dangers of high-voltage electrostatic defocusers? How to avoid it?
When the oxygen content in the fuel gas exceeds the predetermined limit, there is a danger of explosion inside the high-voltage electrostatic decoker; the preventive device is an oxygen content monitor, when the oxygen content in the fuel gas exceeds the predetermined setting, it will automatically shut down The power supply of the high-voltage electrostatic decoking device; at the same time, the safety explosion-proof door in the system, when the gas explodes unexpectedly or the gas pressure rises sharply, it will burst immediately to relieve the pressure.
17. What is the tar content in the gas after passing the ESP (High Voltage Electrostatic Decoker)?
<2 mg/Nm3
18. Why does the gasifier have a furnace knot? How to prevent it?
When the gasification temperature (temperature in the gasifier) ​​fluctuates sharply or rises rapidly, such as the incoming air or the amount of biomass raw materials that enters suddenly changes; the ash in the gasifier is sintered together, and the gas in the gasifier is gradually hindered Circulate and eventually form a crystal mass. The operation of the gasifier should be carefully controlled to keep the temperature in the furnace stable and avoid a sudden rise or drop in the temperature in the gasifier.
19. If the furnace is closed, what shall we do?
Only to shut down the gasifier, remove the agglomerates in the furnace under the condition of ensuring safety, and then restart the furnace.
20. How many workers are needed per shift?
This depends on the operating mode and the operating skills of the workers; for a 1MW, 3-4 people per shift is enough.
 
21. What is the exhaust gas composition of gas-fired units? What's the harm?
The exhaust gas composition of a gas engine depends on the type of biomass raw material, the selection of the gas engine, the load of the gas engine, the load of the gasifier, etc.; the exhaust composition of the general gas engine group is as follows;
CO: 0.15-0.45%
NOX: 100-150 mg/m3
N2: 70-80%
CO2: 15-20%
O2: 0-2%
The exhaust of the engine block is harmful to humans because it contains CO (carbon monoxide) and CO2 (carbon dioxide)
22. What is the exhaust temperature of a gas engine?
This has a certain relationship with the load of the gas engine; at full load operation, the exhaust gas temperature in the main exhaust pipe is about 580℃
23. How do we use the high temperature exhaust gas emitted by the engine?
Dianyan provides engine exhaust waste heat recovery device (optional), which uses high-temperature exhaust gas to produce hot water, steam or thermal oil, etc., which can be used as a heating source. This will significantly improve the thermal efficiency of the entire system.
24. Can we use the high temperature gas from the gasifier?
Yes, it depends on the temperature of the gas produced in different gasification systems and the specific process flow. The gas first passes through the cyclone dust collector for solid separation, which improves the thermal efficiency of the entire system.
25. How much noise does the system have?
The noise of the roots blower is about 80 decibels, and the noise of the gas generator set is about 100 decibels. The above equipment will be installed in the house to minimize the noise impact.
26. How big is the sewage discharge?
Dianyan adopts dry gas purification system
27. What solid waste will be produced? How to deal with it?
After the biomass is reacted in the gasifier, some solid phase products will remain, which we call biomass char. High-quality biomass charcoal can be used as raw materials for machine-made charcoal and activated carbon for sale, and lower-quality biomass charcoal can also be used to produce carbon-based fertilizer or directly returned to the field.
29. Is there secondary pollution?
Dianyan's design is that there is no secondary pollution.
30. How long does it take to start the gasifier?
This depends on the worker's operating proficiency, and it usually takes 20 to 30 minutes.
31. In addition to power generation, are there other uses for gas?
Biomass gas is a kind of combustible gas, which can be used as gas fuel, can be used for centralized gas supply or used as fuel for other thermal energy equipment.
 
32. What is the difference between the electricity generated by BGPS and the electricity generated by other conventional power stations?
There is no difference; the electricity generated from BGPS can be used for self-consumption, or it can be transmitted to the existing grid.
33. What's the model of Dianyan?
The standard unit of Dianyan is 300KW to 2MW; the standard unit can be combined and operated in parallel to become a larger system, or it can be added in stages according to the development stage of the customer;
For example: Two sets of 500KW are connected in parallel to form 1MW, or four sets of 2MW are connected in parallel to form an 8MW system.
34. How long does it take to build a Dianyan BGES? What preparations are needed?
It takes about 3-6 months depending on the size of the project
Design and manufacture (1-3 months)
Simultaneous civil construction (1 month)
 BGPS installation and commissioning (1-2.5 months)
35. Where is a suitable place to build a biomass power plant?
Sufficient biomass raw materials, such as wood chips, rice husks, fruit husks, agricultural crops and forestry wastes, etc.
36. How much investment is needed to build a biomass power plant?
This is based on different regions, scales and specific requirements. Dianyan will provide suggested options and budgets for reference.
As an investment estimate, the investment of BGPS is about 60~75% of the equivalent coal power plant.
37. What is the cost of electricity production?
Mainly based on the cost of biomass raw materials; as an investment budget, when biomass raw materials are almost free, the electricity cost is about RMB 0.1 per kWh; operating costs are based on the plant’s operating mode and local operating conditions, and may vary Quite large; when considering buying BGPS, the local operating cost should be calculated according to local conditions.
 
38. What are the payment terms of Dianyan?
30% advance deposit after signing the contract, 60% delivered before leaving the factory, 5% delivered after commissioning, one-year retention money 5%
 
39. What is the payback period of Dianyan's investment?
The payback period depends on the cost of biomass raw materials, the scale of the project and the operation mode of the plant. Generally speaking, when the scale of BGPS is large, the payback period is shorter; when the biomass raw materials are very cheap, the payback period of a 500~1000 kW power plant is about 3~4 years; however, when purchasing BGPS, the customer needs Conduct economic feasibility review based on local conditions.
 
40. How to pay taxes?
  The contract price signed by the two parties covers taxation in China (including but not limited to tariffs, value-added taxes, direct or indirect social contributions, stamp duties, fees not mentioned here). All other taxes in foreign countries (including but not limited to customs duties, value-added taxes, direct or indirect social contributions, stamp duties, and fees not mentioned here) shall be borne by the buyer and paid directly to the relevant authorities.
 41. Can we use the bank letter of credit L/C?
 Yes, but the opening bank of the letter of credit must be a reputable bank.
42. Why doesn't Dianyan provide cooling towers?
The cooling tower system is a very heavy and bulky equipment, and its transportation cost is very high; it is more cost-effective for customers to buy locally, but the Electric Research Institute provides cooling tower requirements and specifications. Of course, if it is not available locally, Dianyan can also provide cooling towers.
43. Why doesn't Dianyan provide all main power output cables?
Denken can provide large-diameter cables, but at an additional charge. The customer knows the route and cable length of the main output cable clearly. It is more cost-effective for the customer to buy a large cable locally.
44. Can Dianyan provide [power factor improvement equipment]?
Yes, Dianyan can provide power factor capacitor systems; Dianyan has developed a competitive power factor capacitor system in response to BGPS; the power factor capacitor system does not require excessive maintenance, but it can improve the efficiency of the entire power supply system with a return on investment The benefit is very high.
45. Why not use the wind ash delivery system in the new BGPS?
Dianyan has developed a mechanical speed-regulating spiral ash feeding system to replace the previous wind-driven ash feeding system; the new speed-regulating spiral ash feeding system has low cost, high efficiency and environmental protection.
46. ​​Can Dianyan supply all spiral ash conveying systems?
Yes; Dianyan can design and manufacture the corresponding screw ash feeding system.
47. How to apply for various permits, such as construction permit (PTB) and environmental impact assessment (EIA)?
Customers are responsible for applying for and processing all local construction permits, but Dianyan will provide information assistance when needed.
48. Regarding the manpower, tools, hoisting crane, electric welding machine, oxygen and acetylene required for on-site installation?
It is mainly necessary to provide a crane with sufficient lifting weight to load, unload and install large parts. The type and quantity of tools and manpower required for other installations will be provided with a list based on actual project conditions.
49. How to calculate the commissioning engineer's expenses?
In the sales contract, the commissioning cost, construction period and number of commissioning personnel will be clearly stated. Under normal circumstances, the customer provides the commissioning engineer's road expenses, meals and accommodation, local living allowance of 100-150 US dollars/day, and local transportation; Dianyan is responsible for the commissioning engineer's salary and work injury insurance.
50. How much is the self-consumption of the system itself?
10-15% of system output power
51. What is the general technical specification of BGPS?
Biomass material consumption: 1.0 ~ 1.5 kg/kWh
Gas calorific value: ≥1100 ~ 1200 kCal/Nm3
Maximum gas production capacity: 2.5-3Nm3/kg
Gasification efficiency:> 70%
Self-consumption: 10-15%
Continuous power output: 90%
52. What kind of automation does BGPS provide?
Gasification of gas: Provide PLC semi-automatic control cabinet
Gas engine: each engine has a separate monitoring panel
Generator: Each generator set has separate monitoring and synchronization control
53. What kind of operation training is there?
During the commissioning of the equipment, Dianyan will train the operators on the operation of the system equipment.
54. What qualifications are required for technicians?
Dianyan BGPS is not a complicated system; technicians need to have a certain basic knowledge, and they can learn diligently. If the technician has a certain understanding of diesel engines, it is very helpful for the operation and maintenance of gas engines; if electricians have certain basic knowledge of electrical appliances, they can be trained to maintain and overhaul the BGPS control system.
55. Does Dianyan provide BGPS spare parts?
Yes, it is recommended that customers consider purchasing spare parts for 1-3 years when purchasing the complete machine.
56. Does Dianyan provide operation and maintenance manuals?
Yes, when BGPS leaves the factory, we will provide operation and maintenance manuals, as-built drawings, and parts lists.
57. What kind of maintenance does Dianyan provide?
Dianyan will provide a one-year warranty for general mechanical products; the specific warranty provisions will be clearly indicated in the sales contract signed by both parties.
58. Does the Electric Power Research Institute send engineers to install BGPS on site?
Yes, the Electrical Research Institute will send engineers to the site to [Guide Installation]. The specific details of BGPS installation are clearly stipulated in the sales contract signed by the customer and Dianyan; as a general requirement, the customer needs to provide a crane that meets the requirements and the manpower and material resources required for on-site installation.
59. How is BGPS transported?
Basically, all modules are transported in containers, but also in bulk. Basically all containers are exported from Shanghai Port in northern China.
 
60. What kind of installation foundation is needed?
The Electric Power Research Institute provides customers with a reference system layout and basic drawings; basically, it only needs a concrete foundation and a machine room for the gas-fired engine.
61. What should we do if there is not enough water near us?
For places where there is not enough fresh water supply, we do not recommend the use of cooling towers. Instead, we recommend the use of cooling radiators (air cooling).
62. Can we visit Dianyan?
You are very welcome to visit our factory in Zhengzhou, China, please feel free to contact us by email or phone.
63. We don't speak Chinese, how should we communicate with the staff of your electrical research factory?
We have English-speaking colleagues to help both parties communicate, as well as English sales materials and presentations;
Operation and maintenance instructions are also available in English.