Q & A

QUESTION

ANSWER

Are the works specified in the technical and commercial proposal for mini HPP provided on a "turnkey" basis? Or not?

For example, are the following works included:

  • earth-moving and concreting works;
  • use of construction machinery, building framework erection;
  • project with all the sections needed for the expertise and the subsequent authorization, etc. )?

The cost of building and installation works encompasses all works associated with the construction of a facility from the ground, foundation works to equipment commissioning. It covers the installation of the whole set of equipment from fuel supply system to turbine generator, all the buildings and facilities necessary under the project.

The cost of design (stage P and RD ) includes all the operations necessary to obtain a positive expert conclusion on the project on the whole, as required by the RF Government Decree №87 dated February 16, 2008 "On the structure of sections of project documentation and requirements for their content".

Are there additional costs and, if so, what for?

All that is necessary for a normal and safe operation of the boiler house or mini HPP (equipment, buildings and structures, service platforms, stairs, etc.) is included in the scope of supply and the cost is determined in the Section "TOTAL COST OF BOILER EQUIPMENT". The battery limit for delivery is defined as 1 meter from the boiler house building.

The cost of external engineering networks (cable lines from transformer substation to connect the equipment, pipes/steam pipes to the consumers, drain networks, water supply pipeline, etc.), as well as fire extinguishing systems are not included in the basic cost, and according to customer request shall be specified in a separate section.

What portion of the work should be performed by ourselves?

If you choose to hire our company on the EPC contract terms, you do not have to bear any additional costs, except those for external networks mentioned above. However, we may perform these work within the scope of our competence and in accordance with an agreement. In other words, you do not need to enter into agreements with a huge number of different contractors, as you get a complete solution from the hands of WELLONS.RU

What does the 2.5 to 7 MWH power of the turbine generator means?

In 90% of cases, for example, under electricity generation projects implemented at plywood mills, we propose to supply the turbine generator 110 SST. This is a bleeder steam turbine, which meets the needs of low pressure steam consumers. The proposed turbine has a wide power generation range depending on the volume and characteristics of steam provided, as well as on its operating mode (backpressure or condensing mode.)

For example, at maximum load the turbine can produce electricity at a rate of 7 MWH. If operated in intermediate steam bleeding mode, power generation will be lower.

This turbine mode can only be specified in the preliminary budget proposal, in the event that the customer has difficulty in providing base data (e.g., during construction of a new plant). After receiving the base data and developing the design concept, the turbine power rating is indicated precisely.

Does it mean that at the first stage the turbine installed can generate 2.5 MWH, and with the growth capacity of the enterprise, or emergence of new electricity consumers the power output will be increased to 7 MWH?

Unfortunately, this result can only be achieved if there is a surplus in steam production. We cannot say that a growth in the plant 's electricity consumption can be made up by increasing the turbogenerator loading. Without increasing the steam supply to the turbine, it is impossible to raise power output (given a constant or growing number of consumers). Therefore, at the stage of detailed project study a generator capacity has to be determined in accordance with the process steam utilization parameters and of perspective of the plant expansion.

It is important to understand that the plans for further development of primary production should include the possibility of a phased reconstruction of heat and power sector to meet the needs of the plant increasing productivity.

How to ensure stable operation of both the turbine generator and process facilities under different modes of steam consumption, in particular, in summer and winter periods? What can be done with excess steam and power? Can you describe the technological aspect of HPP operation in the context of production (is it possible to schematically, with arrows and heat and energy figures, explain a layman who does not understand this how the energy complex works in general)?  

We offer a comprehensive solution that provides answers to all the questions. The mini HPP complex in question is designed to work in any conditions, no matter what time of year or the number of consumers.

This example shows the flexibility of the system: should a number of technical measures be not provided, judging by the summer operation mode one can say that the steam consumption decreases due to lower heating load if nothing else. It is good, if the power consumption decreases as well because of lowering the lighting load. In fact, these two reasons are not linked proportionally, i.e. there is a conflict between the heat energy production and power generation. What should be done if you want to generate more power, and, at the same time, to cut the amount of heat energy supply to consumers. Or vice versa? What to do with excess steam or surplus electricity?

As a solution to the issue of independent operation of turbo-generator and steam consumers, it is proposed to build a cooling tower system that would compensates for the imbalance between the demand for process steam and the possible generation of power required to operate the plant. This enable a stable production of auxiliary electric power, regardless of the number of consumers, and adjust the turbogenerator to match the plant load (if necessary, if there is no possibility of its supplying electricity to the network).

For a clear understanding of the heat and power complex operation, we are preparing an illustrative block diagram, which will allow you to easily understand the direction of steam and condensate flows, heat energy consumption, etc. The scheme is very simple to understand and practically leaves no questions on the principle of operation of the mini power stations in general.

How is the switchover between the various plant operation modes performed?

For example:

  • decrease of power consumption with simultaneous increase in demand for steam;
  • or vice versa, the process steam consumption falls while a demand for electricity rises;
  • or a minimum power output is required?

 

The power generation and the steam production are regulated as follows:

  • if the electricity consumption falls, the amount of steam at the turbine inlet is reduced by a required volume to lower the power generation. Simultaneously, a larger amount of steam is supplied to a common header to be distributed among consumers.
  • In this case, as much steam is fed to the turbine as is necessary to generate a certain amount of electricity, and the boiler performance is reduced to the desired level of total consumption. Following the extraction from the turbine, surplus steam (if any) goes to the cooling tower and, after condensation, returns to steam production process.
  • As regards the turbine ramping to a minimum load, it is simply achieved by reducing the supply of steam. In doing so, the sufficient amount of steam required for consumption remains in the common steam header.

Which type of turbine generator can be offered (counterpressure, intermediate steam bleeding, etc.)?

 

Any type of turbogenerator can be used. It is specially selected for each project depending on the customer requirements and available financial resources. The most effective solution is sought to allow the maximum project profitability with minimum payback period.

What amount of bark waste (BW) can be disposed of in the mini HPP?

BW consumption depends on the calorific value of the fuel, which is directly dependent on the fuel humidity. Our boilers allow to dispose of biofuels with a moisture content of 65% and above.

If standard fuel is utilized (moisture content – 55%, QНР= 1,700 kcal/kg), it takes ~ 8,000 kg/h to produce 25 MTH of steam (saturated/21 bar).

Fuel consumption is also dependent on the steam parameters, its temperature and pressure. For the production of 40 bar/440°C steam, a slightly larger fuel amount is required.

Is it possible to enter into a direct agreement with a US manufacturer for supply of components and equipment being manufactured in the United States?

For example: if a portion of the funding consists of a dollar loan, it can be spent to purchase the equipment being sold for foreign currency, thus optimizing the VAT, as its compensated immediately after payment at the time of goods arrival, regardless of the delivery of the boiler itself.

Of course, if your wish, you can enter into a direct contract with our head office in the United States, with "Wellons, Inc.". We may divide the total supply contract in two parts – one of them will be in US dollars and the other in rubles. We do not see any problem, the main thing is your convenience.

If yes, what is included in the scope of equipment delivery from the United States?

Complete scope of equipment supplied from the United States is limited to a minimum set of proprietary parts, namely:

  • boiler furnace grate with hydraulic drive;
  • boiler fuel distribution system (fuel auger, metering surge bins with supply augers);
  • ash-handling system.

100% supply of boiler equipment from the USA is possible, however, because of the current exchange-rate value of the ruble, the cost of equipment increases almost twice.