Turn a Hopper Fed Stove to Highest Efficiency ALWAYS

I am chinese in China.
I am reading forum recent weeks.
A stoker stove can always work at highest efficiency for all settings.
a hopper fed stove is designed to work at highest efficiency only at one setting. big or small fire will lower the efficiency.
A second burning may keep the highest efficiency at any setting too as long as the air supply is always favorable.
Morden electronics is so clever, measuring temp. flow speed, content of co/soot, a chip can control air supply to send burning. It must be cheaper and reliable than auger.
Can anyone send me drawings of commercial hopper fed stoves, just add a few sensors, valve, chips,and a short programmer, I can upgrade it to highest efficiency.
highest efficiency means less consumption of coal, and less pulotion of soot, and low risk of fatal co.
I try to keep cost under US$200.

usually those lay's chips are best. you cant just use one tho

I prefer to manually regulate my stove. That way I regulate the efficiency. No expensive electronics needed.

Actually, a pretty sound idea. I think the problem would be a potential market and logistics. Why go for an automatic
nut burning stove when you can buy a rice burner? Where is the advantage to the consumer? Logistically, how many times
would you fill that stove? A larger hopper, what would it look like? As a home project, very cool. But as a commercially viable
product, I believe the current stoker stoves fill that role. I think the attraction of the hand fed is no electricity needed for
operation.
Now a self regulating stove based on mechanical control vs electric, you may have something.

Hello, madeinchina. Thank you for having an interest in making a better coal stove controller. Here's my suggestion. Look at the AHS coalgun boiler. See: http://www.alternateheatingsystems.com/coalboilers.htm It's a gravity feed Anthracite coal only system. It is a "stack" of coal in three states, 1. coal ash, 2. burning coal and 3. feed coal. The amount of feed is controlled by removing ash. New coal then feeds by force of gravity. Forced combustion air controls the fire rate. It's controlled by a boiler water temperature sensor. When to operate the ashing motor is controlled by sensing the air temperature near the ash. The controls are primitive compared to what can be done with modern day electronics.

Coal stoves sell in larger quantity than central heating appliances like coal boilers or coal furnaces. But I believe the central heating appliance market will have more interest in a better controller. For optimum combustion efficiency you will need to sense exhaust flue gases. Analysis this gas for the proper amount of CO2 and O2. Then make adjustments to the combustion blower motor speed. A flue gas sensor would be similar to the lambda sensor in a modern lean burn automotive gasoline engine. It will be quite a challenge to get the control algorithms correct. When to ash and for how long will also be difficult to determine. Whatever you design will need to be configured to the specific characteristics of the coal being burned. Unfortunately coal is not like other heating fuel like, oil, propane or natural gas that have exacting specifications. Good luck. Feel free to send me private e-mail (PM) if you wish.

What kind of coal do they burn in China? Hard coal or soft coal? What kind and brand of stove is most used in China?

chineeze coal is prolly burned in chineeze stove in china I would think..

"

CASE NUMBER: 234
CASE MNEMONIC: CHINCOAL
CASE NAME: China Coal and Pollution

A. IDENTIFICATION

1. THE ISSUE

Coal accounts for about 70% of China's total energy consumption.
The development and production of the coal industry provides
stability in China's economic growth. The coal resources in China
have been exploited since 476 BC, and it is estimated that even
with all the years of coal exploration, China has total coal
deposits of 4, 490 billion tons which are as deep as 2,000 vertical
metres. Eventually China will exploit its coal resources until
they are eliminated. However, this is not the central argument of
this case study. More importantly, the concern is that with the
rapid exploitation and high dependency of coal productivity, China
is damaging not only the physical environment, but China is also
creating health problems for Chinese people, and people in the
surrounding countries.

2. Description

Articles in Worldwatch, Environmental Science Technology, Science,
and World Resources, have demonstrated different types of
environmental degradation due to coal production in China. For
example, in northern China, cities like Beijing and Shenyang have
poor air dispersal and low-level temperature inversions. In fact,
"urban centers in that region record some of the highest readings
in the world for total suspended particulates (TSP) and SO2."

In southern China, areas such as Sichuan, Guangxi, Hunan, Jiangxi,
and Guangdong, have growing acid precipitation problems and overall
emissions of China is increasing. Since coal burning is a major
source of particulates and SO2, this is a main contributor to the
air pollution. To illustrate, in 1992, nationwide emissions of SO2
were estimated at 16.85 million metric tons. This increased 4%
from 1991, and 13% from 1990. Furthermore, soot emissions rose
7.6% in 1992 from 1991.

Another pollutant generated from coal burning is carbon dioxide.
The carbon dioxide emissions from coal burning is larger than any
other energy sources such as, petroleum and liquefied natural gas.
In addition, analysts argue that increases in carbon dioxide will
contribute to global warming. Besides carbon dioxide, sulfur
dioxide, which is believed to cause acid raid, is another pollutant
generated from coal burning. When sulfur dioxide is emitted into
the atmosphere, it takes approximately ten days for it to settle to
the earth. In this period of time, the sulfate particles can
travel several thousand kilometers. China is not the only country
suffering from acid rain problems. Other Asian countries, such as
Japan, Taiwan, S. Korea, and the Philippines have all reported acid
rain problems originating from China's coal burning pollution. The
Central Research Institute of Electric Power and Industry in Japan
has reported that acid rain from the China mainland will soon be a
major problem for Japan. Recent studies in Shimane and Tottori
prefectures claimed, "half of the acidic fallout recorded came from
China, one-third came from Japan, and one-sixth from the Korean
Peninsula".

Toxic substances emitted into the air from coal burning have
dramatically affected human health in China. For example, "chronic
obstructive pulmonary disease (COPD), linked to exposure to fine
particulates, SO2, and cigarette smoke among other factors,
accounted for 26% of all deaths in China in 1988".(1) China's
death rate related to COPD deaths, is five time higher in China
than in the United States. In addition, pulmonary disease and
strokes have increased in Chinese people because of the exposure to
indoor emissions from poor-quality coal used for cooking and
heating. In Xuanwei, for example, scientists have researched the
relationship between lung cancer and particles from indoor coal
combustion.

In sum, coal burning in China is having a significant impact on the
physical environment, as well as the population in China, and the
overall world atmosphere. Scientists have predicted by the year
2025, China will emit more carbon dioxide and sulfur dioxide, two
products from coal burning, than the United States, Japan, and
Canada combined.

China is one of the world's largest coal producers. There is no
known figure on the amount of coal resources in China, but some
estimates have been as high as 1 million tons. China leads as a
coal-rich country with the Soviet Union and the United States in
second and third place respectively. China's coal consists of the
majority being bituminous coal. About 20% is anthracite coal, and
lignite coal makes up the smallest portion.

Since 1949, China has suffered mostly from a shortage of coking
coal. Coking coal is an important part required for the steel
industry. A shortage of coking coal has limited the growth of the
steel industry in China. Another problem with China's coal
resources is its unusual location. Approximately 80% of China's
coal resources are located in mountainous regions far away from the
industrial centers. Therefore, it costs these industries more
money in shipping since they need to transport the coal a good
distance.

Despite these two problems of quality and location, China's coal
industry remains abundant and prosperous. Coal resources in the
pre-war era was more than sufficient to support the industry in
China. The growth in coal production continued more rapidly in the
1950s. By the 1970s, two of the eight mining bureau produced over
10 million tons per year. Today, the coal enterprise is the main
contributor to China's "economic miracle". Coal accounts for 76%
of China's energy supply. With this acceleration however, has also
come significant environmental issues. Two of these problems
include severe air pollutants which is comprised of acid rain and
global warming, and health deterioration in China's population.

The first problem resulting from coal burning is how it pollutes
the air. China has been burning coal since the late 19th and early
20th centuries. The time has come when China is now witnessing the
results of this environmentally unsuitable industry. Even more
astonishing however, is that despite proof of toxic air pollutants
and acid rain, China is making minimal efforts in converting coal
burning plants to more environmentally safe methods. For example,
according to an article dated January 14, 1995 in the South China
Morning Post, a company called Hopewell Holdings is planning to
build a 2,640 mega-watt coal burning plant on the eastern shores of
Mirs Bay. Environmentalists fear that the northeasterly winds
common in this area, will blow the fumes from the plant to Hong
Kong.

When the rain falls in metropolis cities in China, the pollution is
clearly visible. Soot coats the pavement turning it into slippery
muck, and turns the leaves a black-brown color. The Chinese
environmental protection agency has listed five species of
shellfish as newly extinct, and most of the water in rivers fail to
meet fishery standards.(2) Furthermore, the sulfur dioxide
produced from coal burning is drifting to other countries. For
example, ecological problems have been documented in Taiwan, Korea,
Japan, and the Philippines. People in Inner Mongolia have
complained of the water causing skin blisters, and in Beijing the
skies are full of smog. Japan has made the most attempts in
working with China to prevent increased acid rain. The Japanese
government has proposed acid-rain abatement programs which provide
cities in China five-year, low-interest loans to reduce acid rain
degradation. The funding has been capped at $10 billion in loans,
but the plans are still being negotiated. The Chinese government
argues that at least $15 billion should be provided in loans in
order for the project to work. China's officials have been quoted
as saying that if the Japanese are the ones concerned about acid
rain, then they should properly fund what is needed for the
prevention plans to be executed correctly.

The reason why acid rain from China is having such an impact on
Japan, is because China relies heavily on coal as a fuel. Only
about 30% of the country's coal is used for generating electricity.
The rest of the coal is inefficiently used by being burnt directly.
Furthermore, approximately 81% of the coal used in households, is
not washed which causes serious pollution, and health hazards. In
1993, China generated 19 million tons of sulfur dioxide. Recently,
China passed the United States as the world's largest generator of
sulfur dioxide. Since sulfur dioxide is a byproduct of coal
burning, and is also the key component of acid rain, one can
estimate how the acid rain problems will magnify in China in the
near future. Moreover, the equipment required for coal-burning
plants, to reduce the discharge of gases, such as sulfur dioxide,
is in limited supply. Dust-collectors in China have been installed
in the coal-fired plants, but these do not remove the toxins from
the discharged gases. China should model the Japanese by
installing desulfurization and denitrification devices. These
devices remove more than 90% of the virulent gases. So far, China
has made no concrete plans to install these mechanisms.

Air pollutants generated by coal burning relates to another
environmental issue, which is the deteriorating health of the
Chinese population. Scientists have demonstrated that China's
rapid economic growth attributed to the coal industry has led to a
rise in cancer and lung disease. A report from the National
Environmental Protection Agency titled, The Condition of China's
Environment, read, "the death rate due to cancer in urban areas had
increased by 6.2% and that of lung cancer by 18.5% since 1988".(3)
In 1993, China's death rate was 664 per 100,000, and the number one
cause of death was respiratory disease in agricultural areas. In
city areas, the number one cause of death was cancer, and lung
cancer accounted for 37 of every 100,000. In addition, in the
northern urban areas of China, the total suspended particle
readings averaged 407 micrograms per cubic meter per day, and 251
micrograms in southern cities. Some places read as high as 815
micrograms. The World Health Organization safety guidelines are
set between 60 and 90 micrograms for total suspended particles.
China's readings are over two and three times what is considered
healthy.

In Xuan Wei County, Yunnan Province, lung cancer is one of the
highest causes of death particularly in women. Studies have
determined that the lung cancer is associated with the indoor
burning of "smoky" coal, as opposed to smokeless coal or tobacco
smoking. Smoky coal emits high concentrations of sub micron
particles containing mutagenic organics. One study determined an
etiologic link between domestic smoky coal burning and lung cancer
in Xuan Wei. Mumford, Wise, Cao, and Chuang found it unusual that
tobacco smoking is rare in Xuan Wei County females (less than 0.1%)
and more common in males (40% or more), yet the female population
had an abnormally high death rate of lung cancer. The local
industries in this city of one million people, are mostly coal
mining, electric power generation, light manufacturing, and
farming. The mines in Xuan Wei distribute smoky and smokeless
coal. The scientists found that fuel burning in shallow unvented
pits has resulted in high indoor air pollution levels. Moreover,
traditionally the women start the fires and cook, where men spend
most of their time working outside the home. Thus, the lung cancer
in Xuan Wei, "is associated with the domestic use of smoky coal
under unvented conditions".(4) The scientists determined that the
presence of the alkylated three and four-ring PAHs in the smoky
coal which is extracted when the coal is burned, is a significant
factor in the high lung cancer mortality rates in Xuan Wei, China."

"Another pollutant generated from coal burning is carbon dioxide".

I beg to differ on that point! CO2 with O2 are the two most important gasses on earth. Life as we know it would not exist without either.

Just a little off topic!!!

madeinchina wrote:I am chinese in China.
I am reading forum recent weeks.
A stoker stove can always work at highest efficiency for all settings.
a hopper fed stove is designed to work at highest efficiency only at one setting. big or small fire will lower the efficiency.
A second burning may keep the highest efficiency at any setting too as long as the air supply is always favorable.
Morden electronics is so clever, measuring temp. flow speed, content of co/soot, a chip can control air supply to send burning. It must be cheaper and reliable than auger.
Can anyone send me drawings of commercial hopper fed stoves, just add a few sensors, valve, chips,and a short programmer, I can upgrade it to highest efficiency.
highest efficiency means less consumption of coal, and less pulotion of soot, and low risk of fatal co.
I try to keep cost under US$200.

First a few corrections. Any manual stove works best at one setting. Big or small fire is misleading; trying to get low heat output from a large load of coal is the problem, or trying to get high heat output that exceeds the stoves ability to absorb it.

Secondary air also needs enough heat to ignite gases. Hard coal (anthracite) does not make soot, only ash and fly ash.

There is no question that better management of over fire air can lead to higher overall efficiency. Many stoves have no provision at all. Others rely on operator judgment. As Yanche points out even stokers could benefit from better sensing and control.

Lack of over fire air leads not only to increased production of carbon monoxide, as you mention, but also the quality of the ash is different. Ash from completely burned coal is softer and is easier to clear from the grates. Also there will be no puff backs, something that has been more frequently mentioned as members throttle down their stoves with the warmer weather. If your control system could modulate the air (preferably not just on and off but continuously) then I think it would be very worthwhile especially for manufacturers. Wood stoves could also benefit.

I have included several pictures of hopper stoves. Neither one is typical,as most are just an oval shaped tube in the center of the stove and loaded from the top.

The Warm Morning stove has hollow ducts built into the sides of the fire brick to conduct hot gasses to the top of the bed of coal where if the secondary air opening is open they will burn. These stoves have been around for a long time and users all like them. They represent a clever design in a stove that is meant to be inexpensive. The ducts allow the load of coal to act in a way similar to a hopper.

Best Wishes in Your Effort,

Richard

PM me if you wish

Ricard -- really appreciate your post stove is very interesting and your points are accurate.

"stonyloam" Thank-you for your post, as was stated it does drift a bit off the topic but I also
believe members of the forum need to use every opportunity to state the obvious "that
CO2 is not a pollutant" -- there Would be No life Without It. baldeagle

http://greenmindfulness.wordpress.com/2008/03/03/ ... e-methane/

anything when overproduced can become a polluntant. sort of like the crooked politicians that are polluting our lives.

This post sounds like a Chinese manufacturer that wants to get data so they can make a coal stove to sell worldwide. No mo data from this Americanski.

Uglysquirrel wrote:This post sounds like a Chinese manufacturer that wants to get data so they can make a coal stove to sell worldwide. No mo data from this Americanski.

Thanks for your understanding.
I am clear now.
I searched a few patents, I studied a few commercial stoves
I know where the problems are
and I am sure I can upgrade hopper fed stove to more clever, more efficient, less polution of soot/co.
Before next heating season, I will offer 5 sets of upgrading kits to American stove users.
First come first win.
If you sanction China manufacturers, you common American people will spend more during such economic crisis.
If you hate chinese and refuse upgrade your stove, you pollute AMERICAN sky first.
You must be a manufacturer.
If you have time and energy, why do not you upgrade your stove better than made in China.
I dislike some political system and I prefer capitalism too.
But I can not change it, I have to adapt it.
Indeed regardless how loud you shout, you American accept that political system for decades too.
Simply hatred of a common chinese people looks like Germany in world war II.
I love capitalism, I love American, I will do my best to the benifit of American people at cost of hatred by a manufacturer or a competitor.

Well, I think if he wants to copy a stove, it would be a pretty simple matter of buying any one of them he chose to copy.
He would not need us for that. Have to give him credit, his English is way better than our Chinese! He is a coal guy, just
on the other side of the world.